**4.1 NPC histopathologic classification (final clarification?)**

The histopathologic designation of this kind of tumor is matter of debate since the first description of "Primary Carcinoma of Nasopharynx", performed by Chevalier Jackson (1901) based upon the description of 14 cases(Jackson 1901; Van Hasselt and Gibb 1999). From that time on, several designations have been used to designate this tumor, namely lymphoepithelioma, lymphoepitheliomalike carcinoma, lymphoepithelial carcinoma, Schmincke type lymphoepithelioma, Regaud type lymphoepithelioma, transitional cell carcinoma, intermediate cell carcinoma, anaplastic carcinoma, undifferentiated carcinoma with lymphoid stroma, vesicular nucleus cell carcinoma, and so on.

This controversy seems to be solved with the WHO (2003) classification of NPC into three histologic types: keratinizing squamous carcinoma, nonkeratinizing carcinoma and basaloid carcinoma (IARC 2005).

Nasopharyngeal Cancer – An Expanding Puzzle – Claiming for Answers 235

keratinizing squamous carcinoma in one side and nonkeratinizing carcinoma in the other,

However, IARC "WHO Classification of Head and Neck Tumors" (IARC 2005), also describes 6 cases of basaloid squamous cell carcinoma (BSCC) arising as primary tumors of the nasopharynx. These tumors demonstrated to be morphologically identical to the same tumors more commonly occurring in other head and neck sites (larynx, hypopharynx and oropharynx) (Ereno, Gaafar et al. 2008), strongly associated with traditional risk factors,

BSCC of the upper aerodigestive tract was originally described by Wain *et al* (1986) (Wain, Kier et al. 1986), as a rare variant of squamous cell carcinoma, is characterized by clinically aggressive behavior and worse prognosis, independent of tumor stage. Two major histopathologic features define BSCC. Morphologically, BSCC also possess distinct histological features, presenting basaloid tumor cells (solid, lobular, small, crowded cells with scant cytoplasm, hyperchromatic round nuclei, and small cystic spaces containing PAS-or alcian blue–positive myxoid material) in a festooning growth pattern, interspersed

These histopathologic features are also very similar with those of oropharyngeal human papillomavirus (HPV)–related nonkeratinizing squamous cell carcinoma (NK SCC). This kind of carcinoma occurs predominantly in the tonsillar tissue of the oropharynx, in younger patients and have unique risk factors related to sexual behavior, including multiple partners, early age at first intercourse, and oral sex (Chernock, El-Mofty et al. 2009). The tumor appears to show a lower clinical aggressiveness compared with basaloid squamous

The analogy between viral etiology and histomorphological characteristics of tumor development site (close relationship between epithelium and lymphoid tissue) in HPV– related"basaloid" NK SCC of oropharynx and NPC nonkeratinizing carcinoma EBV-related, seems to be quite obvious, but not completely clarified, and so are their histopathologic

Considering all nasopharyngeal tumors, the probability of being originated in the epithelial lining varies from 75 to 95% in low-risk populations, and all of them are virtually cancers in high-risk population (Parkin DM 2002). NPC is a patchy worldwide malignant disease, characterized by remarkable divergence in incidences among populations of diverse

by tumor cells with squamous differentiation (Chernock, Lewis et al. 2010).

cell carcinoma occurring in other head and neck sites (Begum and Westra 2008).

this later being linked to previous infection by Epstein–Barr virus.

Fig. 5. The undifferentiated subtype of NPC.

such as tobacco and alcohol abuse.

**4.2 NPC commented epidemiologic data**

patterns.

#### Fig. 4. Keratinizing squamous carcinoma.

In keratinizing squamous carcinoma, the polygonal and stratified tumor cells grow in the form of irregular islands, accompanied by an abundant desmoplastic stroma infiltrated by variable numbers of lymphocytes, plasma cells, neutrophils and eosinophils. The cell borders are distinct and separated by intercellular bridges and possess abundant cytoplasm and small hiperchromatic nucleus. Often keratin pearls can be seen (Figure 4).

Oppositely, the undifferentiated subtype of nonkeratinizing carcinoma is characterized by syncytial-appearing large tumor cells with indistinct cell borders, round to oval vesicular nuclei, and large central nucleoli, scanty cytoplasm. Often immunostaining for cytokeratins (eg MNF116) is needed to demonstrate the epithelial nature of the tumor (Figure 5).

WHO (2003) classification recognizes the behavior similarities between diferentiated and undiferentiated subtypes of nonkeratinizing carcinoma (type II and III of the previous WHO classification-1978) (IARC 2005). Accordingly, there is clinical, histopathologic and immunologic evidence that nasopharyngeal carcinomas constitute two distinct diseases, keratinizing squamous carcinoma in one side and nonkeratinizing carcinoma in the other, this later being linked to previous infection by Epstein–Barr virus.

Fig. 5. The undifferentiated subtype of NPC.

234 Carcinogenesis, Diagnosis, and Molecular Targeted Treatment for Nasopharyngeal Carcinoma

These results performed in low-risk, non-endemic areas indicate that these genetic variations may represent risk markers for NPC and contribute to the definition of genetic susceptibility profiles for the development of this disease. Furthermore, the knowledge of the mechanisms involved in NPC carcinogenesis may help to identify targets for the

The histopathologic designation of this kind of tumor is matter of debate since the first description of "Primary Carcinoma of Nasopharynx", performed by Chevalier Jackson (1901) based upon the description of 14 cases(Jackson 1901; Van Hasselt and Gibb 1999). From that time on, several designations have been used to designate this tumor, namely lymphoepithelioma, lymphoepitheliomalike carcinoma, lymphoepithelial carcinoma, Schmincke type lymphoepithelioma, Regaud type lymphoepithelioma, transitional cell carcinoma, intermediate cell carcinoma, anaplastic carcinoma, undifferentiated carcinoma

This controversy seems to be solved with the WHO (2003) classification of NPC into three histologic types: keratinizing squamous carcinoma, nonkeratinizing carcinoma and basaloid

In keratinizing squamous carcinoma, the polygonal and stratified tumor cells grow in the form of irregular islands, accompanied by an abundant desmoplastic stroma infiltrated by variable numbers of lymphocytes, plasma cells, neutrophils and eosinophils. The cell borders are distinct and separated by intercellular bridges and possess abundant cytoplasm

Oppositely, the undifferentiated subtype of nonkeratinizing carcinoma is characterized by syncytial-appearing large tumor cells with indistinct cell borders, round to oval vesicular nuclei, and large central nucleoli, scanty cytoplasm. Often immunostaining for cytokeratins

WHO (2003) classification recognizes the behavior similarities between diferentiated and undiferentiated subtypes of nonkeratinizing carcinoma (type II and III of the previous WHO classification-1978) (IARC 2005). Accordingly, there is clinical, histopathologic and immunologic evidence that nasopharyngeal carcinomas constitute two distinct diseases,

and small hiperchromatic nucleus. Often keratin pearls can be seen (Figure 4).

(eg MNF116) is needed to demonstrate the epithelial nature of the tumor (Figure 5).

development of chemoprevention or therapeutic strategies.

**4.1 NPC histopathologic classification (final clarification?)**

with lymphoid stroma, vesicular nucleus cell carcinoma, and so on.

**4. The Nasopharyngeal Carcinoma (NPC)**

carcinoma (IARC 2005).

Fig. 4. Keratinizing squamous carcinoma.

However, IARC "WHO Classification of Head and Neck Tumors" (IARC 2005), also describes 6 cases of basaloid squamous cell carcinoma (BSCC) arising as primary tumors of the nasopharynx. These tumors demonstrated to be morphologically identical to the same tumors more commonly occurring in other head and neck sites (larynx, hypopharynx and oropharynx) (Ereno, Gaafar et al. 2008), strongly associated with traditional risk factors, such as tobacco and alcohol abuse.

BSCC of the upper aerodigestive tract was originally described by Wain *et al* (1986) (Wain, Kier et al. 1986), as a rare variant of squamous cell carcinoma, is characterized by clinically aggressive behavior and worse prognosis, independent of tumor stage. Two major histopathologic features define BSCC. Morphologically, BSCC also possess distinct histological features, presenting basaloid tumor cells (solid, lobular, small, crowded cells with scant cytoplasm, hyperchromatic round nuclei, and small cystic spaces containing PAS-or alcian blue–positive myxoid material) in a festooning growth pattern, interspersed by tumor cells with squamous differentiation (Chernock, Lewis et al. 2010).

These histopathologic features are also very similar with those of oropharyngeal human papillomavirus (HPV)–related nonkeratinizing squamous cell carcinoma (NK SCC). This kind of carcinoma occurs predominantly in the tonsillar tissue of the oropharynx, in younger patients and have unique risk factors related to sexual behavior, including multiple partners, early age at first intercourse, and oral sex (Chernock, El-Mofty et al. 2009). The tumor appears to show a lower clinical aggressiveness compared with basaloid squamous cell carcinoma occurring in other head and neck sites (Begum and Westra 2008).

The analogy between viral etiology and histomorphological characteristics of tumor development site (close relationship between epithelium and lymphoid tissue) in HPV– related"basaloid" NK SCC of oropharynx and NPC nonkeratinizing carcinoma EBV-related, seems to be quite obvious, but not completely clarified, and so are their histopathologic patterns.

#### **4.2 NPC commented epidemiologic data**

Considering all nasopharyngeal tumors, the probability of being originated in the epithelial lining varies from 75 to 95% in low-risk populations, and all of them are virtually cancers in high-risk population (Parkin DM 2002). NPC is a patchy worldwide malignant disease, characterized by remarkable divergence in incidences among populations of diverse

Nasopharyngeal Cancer – An Expanding Puzzle – Claiming for Answers 237

Wei Tian *et al* (Tian, Zeng et al. 2006) demonstrated a positive association between MICA\*A9 and nasopharyngeal carcinoma, only observed in male subjects, and this finding had statistical significance (P=0.0001). This fact is not well explained, but it should be

Furthermore, a recent study demonstrated the existence of a binding site in the long intron 1 of the MICA gene for NF-kappaB (Molinero, Fuertes et al. 2004). It has been shown that physiologic concentrations of male hormones (androgens) cause prolonged NF-kappaB DNA binding activities, which are diminished by vitamins C and E (Ripple, Henry et al. 1999)and estrogen inhibits NF-kappa B activity (Ghisletti, Meda et al. 2005; Kalaitzidis and Gilmore 2005). These findings are mostly fascinating when we consider that TRAF is

The NPC age distribution is also quite different than usual, and seems to vary according to the incidence. It is accepted that in low-risk countries, the NPC incidence rises monotonically with age, but in high-risk regions the age incidence hit the highest point at 55 years(Chang and Adami 2006), showing bimodal age presentation in Northern Africa and India (Bray, Haugen et al. 2008). These results also need an explanation, namely on the influence of some genetic polymorphisms that may influence the age of onset of disease

The close relationship between nonkeratinizing NPC and EBV is sustained by *"in-situ"* hybridization studies (Wei and Sham 2005) and occurs both in endemic as in non-endemic countries (Niedobitek, Hansmann et al. 1991; Breda, Catarino et al. 2010). However, infection with EBV is a worldwide phenomenon and other endogenous and exogenous factors must be associated with NPC development. The relative weight of these factors is not

Whatever its localization, cancer prognosis will conceptually depend on biological

The tumor, node, metastasis (TNM) staging system, allows clinicians to categorize tumors of the head and neck region in a specific manner, to assist with the assessment of disease status, prognosis and management (Daniel G. Deschler 2008). The introduction of several clinical staging systems (American Joint Committee on Cancer (AJCC) staging, the International Union Against Cancer (UICC) staging, Ho's staging from Hong Kong, Fuzhou staging from Mainland China, Huang's or Hsu's staging from Taiwan), permitted that TNM staging for NPC remained relatively confused during many years and this was undesirable. It is accepted that a good TNM classification should fulfill the following criteria:(1) the subgroups defined by T, N, and M that make up a given group within a grouping scheme must have similar survival rates (hazard consistency); (2) the survival rates must differ among the groups (hazard discrimination); (3) the prediction of cure must be high (outcome prediction); and (4) the distribution of patients among the groups must be balanced (Groome, Schulze et al. 2001). The association between the AJCC and UICC staging systems and their succeeding modifications taking into account the criteria previously enunciated,

aggressiveness of tumor itself, host characteristics and therapeutic options.

remembered that HLA genes are sex-linked and transmitted in bloc.

activated by the LMP1 latent EBV protein.

(Catarino, Pereira et al. 2008; Sousa H 2010).

yet clearly understood, namely in non-endemic regions.

**4.3 NPC stage classification and prognostic evaluation**

geographic regions and races. It is very common in southern Asia (20-30/100 000 inhabitants/year) (Vasef, Ferlito et al. 1997) and quite rare in western countries (<1/100 000 inhabitants/year) (Parkin DM 2002). Intermediate incidence (8-12/100000 inhabitants/year) occurs in certain African and Mediterranean populations (Cvitkovic, Bachouchi et al. 1991) and also in the Inuits from Greenland and Alaska and Malays from Singapore and Malaysia.

The relative percentage of NPC types according to the WHO classification seems to vary accordingly to the geographic distribution with about 95% rates of nonkeratinizing carcinoma in endemic regions (Wenig 1999) and 75% of keratinizing squamous carcinoma in countries with low prevalence of the disease, as in United States of America (Marks, Phillips et al. 1998). As far as we know, there is no European statistics dealing about this point, and online search at the GLOBACAN, doesn't discriminate these histopathologic types. However detailed studies in a non-endemic European country (Portugal), reveal that in this population the relative rate of nonkeratinizing/keratinizing carcinoma is closer to the findings obtained in endemic countries (Breda, Catarino et al. 2007; d'Espiney Amaro, Montalvao et al. 2009) (Table 1). These findings suggest that studies envisaging the possible rearrangement of the relative weight of the different NPC types in European populations are needed.

Table 1. Nasopharyngeal carcinoma in Portugal

It is also known that nonkeratizing NPC has a male preponderance and occurs earlier in life than head and neck carcinomas (Parkin DM 2002). These aspects are quite intriguing, as none of the commonly cited endogenous and exogenous risk factors for NPC seem to be directly linked to gender or age of cancer development.

Familial clustering has also been frequently reported (Zhang and Zhang 1999), and can be explained by the demonstration of correlation between the HLA haplotype and NPC susceptibility. However, these very interesting findings need also to be better understood.

It has been hypothesized that certain HLA polymorphic antigens have lower efficiency in activating the cytotoxic T cell recognition and host immune response to EBV infection (Lu, Day et al. 1990; Lo, To et al. 2004). In this context, potential role of the MHC class I chain– related A (MICA) gene belonging to the nonclassical HLA family and located 46 kb centromeric to the human leukocyte antigen (HLA)–B gene is of particular interest. MICA is highly polymorphic, with more than 60 alleles (defined by nucleotide substitutions within exons encoding the three alfa-domains) described to date. Each of these variants is characterized by the presence of a variable number of short tandem repeats (STRs) within the exon encoding for the transmembrane region of the molecule(Douik, Ben Chaaben et al. 2009).There are multiple evidences that the MICA\*A9 is linked with several of those HLA haplotypes NPC related (HLA-B35, -B38, -B39, -B51, -B58) (Chan, Day et al. 1983; Wu, Hwang et al. 1989; Zhu, Chen et al. 1990; Tian, Boggs et al. 2001).

geographic regions and races. It is very common in southern Asia (20-30/100 000 inhabitants/year) (Vasef, Ferlito et al. 1997) and quite rare in western countries (<1/100 000 inhabitants/year) (Parkin DM 2002). Intermediate incidence (8-12/100000 inhabitants/year) occurs in certain African and Mediterranean populations (Cvitkovic, Bachouchi et al. 1991) and also in the Inuits from Greenland and Alaska and Malays from Singapore and Malaysia. The relative percentage of NPC types according to the WHO classification seems to vary accordingly to the geographic distribution with about 95% rates of nonkeratinizing carcinoma in endemic regions (Wenig 1999) and 75% of keratinizing squamous carcinoma in countries with low prevalence of the disease, as in United States of America (Marks, Phillips et al. 1998). As far as we know, there is no European statistics dealing about this point, and online search at the GLOBACAN, doesn't discriminate these histopathologic types. However detailed studies in a non-endemic European country (Portugal), reveal that in this population the relative rate of nonkeratinizing/keratinizing carcinoma is closer to the findings obtained in endemic countries (Breda, Catarino et al. 2007; d'Espiney Amaro, Montalvao et al. 2009) (Table 1). These findings suggest that studies envisaging the possible rearrangement of the relative weight of the different NPC types in European populations

**Nasopharyngeal Carcinoma in Portugal (age, sex and histopathologic distribution)**

GENDER (%) m/f

WHO TYPE II/III (%)

(years)

**IPO-PORTO** 320 48 67/33 93,75% **IPO-LISBOA** 157 53 65/35 88%

It is also known that nonkeratizing NPC has a male preponderance and occurs earlier in life than head and neck carcinomas (Parkin DM 2002). These aspects are quite intriguing, as none of the commonly cited endogenous and exogenous risk factors for NPC seem to be

Familial clustering has also been frequently reported (Zhang and Zhang 1999), and can be explained by the demonstration of correlation between the HLA haplotype and NPC susceptibility. However, these very interesting findings need also to be better understood.

It has been hypothesized that certain HLA polymorphic antigens have lower efficiency in activating the cytotoxic T cell recognition and host immune response to EBV infection (Lu, Day et al. 1990; Lo, To et al. 2004). In this context, potential role of the MHC class I chain– related A (MICA) gene belonging to the nonclassical HLA family and located 46 kb centromeric to the human leukocyte antigen (HLA)–B gene is of particular interest. MICA is highly polymorphic, with more than 60 alleles (defined by nucleotide substitutions within exons encoding the three alfa-domains) described to date. Each of these variants is characterized by the presence of a variable number of short tandem repeats (STRs) within the exon encoding for the transmembrane region of the molecule(Douik, Ben Chaaben et al. 2009).There are multiple evidences that the MICA\*A9 is linked with several of those HLA haplotypes NPC related (HLA-B35, -B38, -B39, -B51, -B58) (Chan, Day et al. 1983; Wu,

**INSTITUTION** N. PATIENTS AVERAGE AGE

directly linked to gender or age of cancer development.

Hwang et al. 1989; Zhu, Chen et al. 1990; Tian, Boggs et al. 2001).

Table 1. Nasopharyngeal carcinoma in Portugal

are needed.

Wei Tian *et al* (Tian, Zeng et al. 2006) demonstrated a positive association between MICA\*A9 and nasopharyngeal carcinoma, only observed in male subjects, and this finding had statistical significance (P=0.0001). This fact is not well explained, but it should be remembered that HLA genes are sex-linked and transmitted in bloc.

Furthermore, a recent study demonstrated the existence of a binding site in the long intron 1 of the MICA gene for NF-kappaB (Molinero, Fuertes et al. 2004). It has been shown that physiologic concentrations of male hormones (androgens) cause prolonged NF-kappaB DNA binding activities, which are diminished by vitamins C and E (Ripple, Henry et al. 1999)and estrogen inhibits NF-kappa B activity (Ghisletti, Meda et al. 2005; Kalaitzidis and Gilmore 2005). These findings are mostly fascinating when we consider that TRAF is activated by the LMP1 latent EBV protein.

The NPC age distribution is also quite different than usual, and seems to vary according to the incidence. It is accepted that in low-risk countries, the NPC incidence rises monotonically with age, but in high-risk regions the age incidence hit the highest point at 55 years(Chang and Adami 2006), showing bimodal age presentation in Northern Africa and India (Bray, Haugen et al. 2008). These results also need an explanation, namely on the influence of some genetic polymorphisms that may influence the age of onset of disease (Catarino, Pereira et al. 2008; Sousa H 2010).

The close relationship between nonkeratinizing NPC and EBV is sustained by *"in-situ"* hybridization studies (Wei and Sham 2005) and occurs both in endemic as in non-endemic countries (Niedobitek, Hansmann et al. 1991; Breda, Catarino et al. 2010). However, infection with EBV is a worldwide phenomenon and other endogenous and exogenous factors must be associated with NPC development. The relative weight of these factors is not yet clearly understood, namely in non-endemic regions.

#### **4.3 NPC stage classification and prognostic evaluation**

Whatever its localization, cancer prognosis will conceptually depend on biological aggressiveness of tumor itself, host characteristics and therapeutic options.

The tumor, node, metastasis (TNM) staging system, allows clinicians to categorize tumors of the head and neck region in a specific manner, to assist with the assessment of disease status, prognosis and management (Daniel G. Deschler 2008). The introduction of several clinical staging systems (American Joint Committee on Cancer (AJCC) staging, the International Union Against Cancer (UICC) staging, Ho's staging from Hong Kong, Fuzhou staging from Mainland China, Huang's or Hsu's staging from Taiwan), permitted that TNM staging for NPC remained relatively confused during many years and this was undesirable.

It is accepted that a good TNM classification should fulfill the following criteria:(1) the subgroups defined by T, N, and M that make up a given group within a grouping scheme must have similar survival rates (hazard consistency); (2) the survival rates must differ among the groups (hazard discrimination); (3) the prediction of cure must be high (outcome prediction); and (4) the distribution of patients among the groups must be balanced (Groome, Schulze et al. 2001). The association between the AJCC and UICC staging systems and their succeeding modifications taking into account the criteria previously enunciated,

Nasopharyngeal Cancer – An Expanding Puzzle – Claiming for Answers 239

The advantages of adding chemotherapy (Ch) to RT had already been accomplished by the Intergroup 0099 study, the first prospectively randomized study to demonstrate an improvement in OS from the addition of concurrent chemotherapy and adjuvant chemotherapy to radiation therapy (when compared with radiation therapy alone), without

From that time on, several trials confirmed not only that the addition of chemotherapy concurrent with radiation therapy has improved the outcomes of patients with NPC, but also that improvements in radiation treatment technology and the adoption of IMRT (Intensity-Modulated Radiation Therapy) have also improved local control, reducing also

Besides the superior dose conformity delivered to tumor, one of the most important promised advantages of IMRT is the achievement of sufficient sparing of critical normal structures adjacent to treated areas, namely spinal cord, parotid glands, temporomandibular joint, middle and inner ears, skin (in the region of the target volumes), and oral cavity, mandible, glottic larynx, brachial plexus, and esophagus (including postcricoid pharynx)

However, even with IMRT, minor salivary glands and both palatal and masticator muscles (medial pterygoid and lateral pterygoid) are often included in target volumes, either gross tumor volume (GTV), clinical target volume (CTV) or planned target volume (PTV). The impact of such distresses on Quality of life (QoL) seems not to be disentangled enough

Quality of life refers to the perception of the effects of disease and its impact on the patient's daily functioning; QoL is a multi-dimensional issue, incorporating physical, psychological, social and emotional domains, and it must be self-reported according to the patient's own experiences (List and Stracks 2000). These very important mind and corporal approach is not often mentioned in scientific literature; usually, the endpoint of medical care for cancer patients is focused on the survival rate, local control rate, or complication rate. These endpoints were typically assessed from the physician's points of view and lacked knowledge of patients' mental or emotional well-being. According to Fang and co-workers (Fang, Tsai et al. 2010), in addition to socioeconomic levels, advanced RT techniques were observed to play a significant role in improving the QoL outcome of NPC survivors. However, the impact size from conventional 2DRT to 3DCRT or IMRT varied on different QoL scales. The therapeutic benefit of IMRT over 2DRT, especially on the swallowing-

One of the main aims of clinical or translational research in cancer is the search for biological factors that could foresee treatment outcomes, in biologic activity and toxic effects. The increasing amount of information regarding the role of genetics in human diseases has led to putative new biomarkers and the development of new fields, as pharmacogenomics (PGx). Pharmacogenomics is a rapidly developing scientific area, especially in oncology. In the most ideal situation, pharmacogenomics will allow oncologists to individualize therapy based on patients' individual germline genetic test results. This can help to improve efficacy, reduce toxicity and predict non-responders in a way that alternative therapy can be chosen or individual dose adjustments can be made. It has been observed that the interpatient variability in response to medications is associated with a spectrum of outcomes, ranging

unacceptably increasing the toxicity of treatment (Al-Sarraf, LeBlanc et al. 1998).

(Brady, Heilman et al. 2010) and such sparing has obvious advantages.

related QoL scales, is not clear and should be further explored.

(Bhatia, King et al. 2009; Lee, Harris et al. 2009).

the morbidity.

namely with rearrangements on T and N arrays, allowed a better TNM prognostic significance in the most recent classifications (Liu, Tang et al. 2008).

However, NPC TNM classification only takes into account the aggressiveness of the "clinical" tumor; understand all the factors influencing the clinical course of NPC in order to improve the TNM classification (Greene, Page et al. 2002) and anticipate NPC prognosis, is still a challenge, recognized by several authors (Lee, Au et al. 2004; Liu, Tang et al. 2008). Accordingly, other tumor characterystics may confirm relevance on prognosis, suhc as histological types (WHO type II and III versus type I). Furthermore, taking into account the relationship between histological types and EBV, it also seems to be very interesting to know how relevant can be the measurement of EBV related proteins in the patient's serum as a prognostic factor of survival. Plasma EBV-DNA measurement is actually believed to be a more sensitive and specific marker than the serum IgA/VCA titer for the diagnosis and monitoring of patients with NPC (Shao, Li et al. 2004). Even more, plasma EBV-DNA findings provide convincing evidence of their usefulness on the early diagnosis and staging of NPC as well as for monitoring recurrence and metastasis of this tumor. Some studies indicate that high marker level (>500 copies/ml) at 6 weeks after radio(chemo)therapy is a powerful prognosticator of recurrence, whereas pretreatment EBV DNA is a better discriminator of prognosis than conventional TNM classification for stage II NPC (Haddad 2011).

Patient's related prognostic factors are seldom referred in literature. Some authors claim that patients with younger age are associated with improved overall survival. One study involving 2,054 NPC patients from several European countries also showed that overall survival declined with age (Jiong, Berrino et al. 1998), and other series from endemic regions demonstrated similar results (Leung, Tung et al. 2005) (Liu, Tang et al. 2008). However, not always is disentangled age with better performance status and less comorbidity characteristics, more often present in younger patients, which might contribute to better tolerance to radical radio(chemo)therapy, thus resulting in better survival.

The relationship between gender and prognosis is subject to similar doubts (Leung, Tung et al. 2005) (Liu, Tang et al. 2008) with controversial results being described. Again, it is difficult to straighten out gender with lifestyle (including body weight, central adiposity, physical activity, exposure to smoking, fruit and vegetable intake a.s.o. and these aspects still wait for clarification.

#### **4.4 NPC treatment, survival rate and quality of life**

Radiation therapy (RT) is considered the mainstay treatment for NPC. Recent retrospective analysis including more than two thousand patients treated by RT alone (mostly using 2D technique) showed that the 5-year overall survival (OS) was 85% for stages I–II (Lee, Sze et al. 2005), corroborating that NPC is highly sensitive to ionizing radiation. However, the same study demonstrated an OS of only 66% for stages III–IVB, with metastatic rate remaining high (25% at 5-years) for patients who achieved locoregional control, and these findings supported the need of some kind of systemic treatment, namely for advanced disease.

namely with rearrangements on T and N arrays, allowed a better TNM prognostic

However, NPC TNM classification only takes into account the aggressiveness of the "clinical" tumor; understand all the factors influencing the clinical course of NPC in order to improve the TNM classification (Greene, Page et al. 2002) and anticipate NPC prognosis, is still a challenge, recognized by several authors (Lee, Au et al. 2004; Liu, Tang et al. 2008). Accordingly, other tumor characterystics may confirm relevance on prognosis, suhc as histological types (WHO type II and III versus type I). Furthermore, taking into account the relationship between histological types and EBV, it also seems to be very interesting to know how relevant can be the measurement of EBV related proteins in the patient's serum as a prognostic factor of survival. Plasma EBV-DNA measurement is actually believed to be a more sensitive and specific marker than the serum IgA/VCA titer for the diagnosis and monitoring of patients with NPC (Shao, Li et al. 2004). Even more, plasma EBV-DNA findings provide convincing evidence of their usefulness on the early diagnosis and staging of NPC as well as for monitoring recurrence and metastasis of this tumor. Some studies indicate that high marker level (>500 copies/ml) at 6 weeks after radio(chemo)therapy is a powerful prognosticator of recurrence, whereas pretreatment EBV DNA is a better discriminator of prognosis than conventional TNM classification for

Patient's related prognostic factors are seldom referred in literature. Some authors claim that patients with younger age are associated with improved overall survival. One study involving 2,054 NPC patients from several European countries also showed that overall survival declined with age (Jiong, Berrino et al. 1998), and other series from endemic regions demonstrated similar results (Leung, Tung et al. 2005) (Liu, Tang et al. 2008). However, not always is disentangled age with better performance status and less comorbidity characteristics, more often present in younger patients, which might contribute to better tolerance to radical radio(chemo)therapy, thus resulting in better

The relationship between gender and prognosis is subject to similar doubts (Leung, Tung et al. 2005) (Liu, Tang et al. 2008) with controversial results being described. Again, it is difficult to straighten out gender with lifestyle (including body weight, central adiposity, physical activity, exposure to smoking, fruit and vegetable intake a.s.o. and these aspects

Radiation therapy (RT) is considered the mainstay treatment for NPC. Recent retrospective analysis including more than two thousand patients treated by RT alone (mostly using 2D technique) showed that the 5-year overall survival (OS) was 85% for stages I–II (Lee, Sze et al. 2005), corroborating that NPC is highly sensitive to ionizing radiation. However, the same study demonstrated an OS of only 66% for stages III–IVB, with metastatic rate remaining high (25% at 5-years) for patients who achieved locoregional control, and these findings supported the need of some kind of systemic treatment, namely for advanced

significance in the most recent classifications (Liu, Tang et al. 2008).

stage II NPC (Haddad 2011).

still wait for clarification.

**4.4 NPC treatment, survival rate and quality of life**

survival.

disease.

The advantages of adding chemotherapy (Ch) to RT had already been accomplished by the Intergroup 0099 study, the first prospectively randomized study to demonstrate an improvement in OS from the addition of concurrent chemotherapy and adjuvant chemotherapy to radiation therapy (when compared with radiation therapy alone), without unacceptably increasing the toxicity of treatment (Al-Sarraf, LeBlanc et al. 1998).

From that time on, several trials confirmed not only that the addition of chemotherapy concurrent with radiation therapy has improved the outcomes of patients with NPC, but also that improvements in radiation treatment technology and the adoption of IMRT (Intensity-Modulated Radiation Therapy) have also improved local control, reducing also the morbidity.

Besides the superior dose conformity delivered to tumor, one of the most important promised advantages of IMRT is the achievement of sufficient sparing of critical normal structures adjacent to treated areas, namely spinal cord, parotid glands, temporomandibular joint, middle and inner ears, skin (in the region of the target volumes), and oral cavity, mandible, glottic larynx, brachial plexus, and esophagus (including postcricoid pharynx) (Brady, Heilman et al. 2010) and such sparing has obvious advantages.

However, even with IMRT, minor salivary glands and both palatal and masticator muscles (medial pterygoid and lateral pterygoid) are often included in target volumes, either gross tumor volume (GTV), clinical target volume (CTV) or planned target volume (PTV). The impact of such distresses on Quality of life (QoL) seems not to be disentangled enough (Bhatia, King et al. 2009; Lee, Harris et al. 2009).

Quality of life refers to the perception of the effects of disease and its impact on the patient's daily functioning; QoL is a multi-dimensional issue, incorporating physical, psychological, social and emotional domains, and it must be self-reported according to the patient's own experiences (List and Stracks 2000). These very important mind and corporal approach is not often mentioned in scientific literature; usually, the endpoint of medical care for cancer patients is focused on the survival rate, local control rate, or complication rate. These endpoints were typically assessed from the physician's points of view and lacked knowledge of patients' mental or emotional well-being. According to Fang and co-workers (Fang, Tsai et al. 2010), in addition to socioeconomic levels, advanced RT techniques were observed to play a significant role in improving the QoL outcome of NPC survivors. However, the impact size from conventional 2DRT to 3DCRT or IMRT varied on different QoL scales. The therapeutic benefit of IMRT over 2DRT, especially on the swallowingrelated QoL scales, is not clear and should be further explored.

One of the main aims of clinical or translational research in cancer is the search for biological factors that could foresee treatment outcomes, in biologic activity and toxic effects. The increasing amount of information regarding the role of genetics in human diseases has led to putative new biomarkers and the development of new fields, as pharmacogenomics (PGx). Pharmacogenomics is a rapidly developing scientific area, especially in oncology. In the most ideal situation, pharmacogenomics will allow oncologists to individualize therapy based on patients' individual germline genetic test results. This can help to improve efficacy, reduce toxicity and predict non-responders in a way that alternative therapy can be chosen or individual dose adjustments can be made. It has been observed that the interpatient variability in response to medications is associated with a spectrum of outcomes, ranging

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from failure to demonstrate an expected therapeutic effect, to an adverse reaction resulting in significant patient morbidity and mortality, decreasing quality of life, as well as increasing healthcare costs.

The goal of the emerging disciplines of pharmacogenomics is to personalize therapy based on an individual's genotype. To date, the success of PGx has spread across all fields of medicine, although little is known about the genetic profile and its correlation with treatment response and overall survival in nasopharyngeal cancer patients. Genetic information has been used in the identification of disease risk, choice of treatment agents and guiding drug dosing. This is particularly important for chemotherapeutic agents, which in general affect both tumor and non-tumor cells and thus have a narrow therapeutic index, with the potential for life-threatening toxicity. Future work should explore the role of genetic variations in nasopharyngeal cancer patients, in a pharmacogenomics approach.