High-dose preoperative radiation and full-thickness local excision Pathologic Complete Response After Neoadjuvant Treatment for Rectal Cancer Decreases Distant Recurrence and Could Eradicate Local Recurrence Optimal Timing of Surgery After Chemoradiation for Advanced Rectal Cancer: Preliminary Results of a Multicenter, Nonrandomized Phase II Prospective Trial A prospective randomized study with a 5-year minimum follow-up evaluation of transanal endoscopic microsurgery versus laparoscopic total mesorectal excision after neoadjuvant therapy Sequential FDG-PET/CT reliably predicts response of locally advanced rectal cancer to neo-adjuvant chemo-radiation therapy Response prediction by FDG-PET after neoadjuvant radiochemotherapy and combined regional hyperthermia of rectal cancer: correlation with endorectal ultrasound and histopathology PET-based treatment response evaluation in rectal cancer: prediction and validation. Preoperative chemoradiation followed by transanal excision for rectal cancer. Locally advanced rectal carcinoma treated with preoperative chemotherapy and radiation therapy: preliminary analysis of diffusion-weighted MR imaging for early detection of tumor histopathologic downstaging. Restaging after neoadjuvant chemoradiotherapy for rectal adenocarcinoma: role of F18-FDG PET. Locally advanced rectal cancer: MR imaging in prediction of response after preoperative chemotherapy and radiation therapy. Use of molecular imaging to predict clinical outcome in patients with rectal cancer after preoperative chemotherapy and radiation. Assessing the predictive value of clinical complete response to neoadjuvant therapy for rectal cancer: an analysis of 488 patients. Clinical examination following preoperative chemoradiation for rectal cancer is not a reliable surrogate end point. Preoperative radiotherapy and local excision of rectal cancer with immediate radical re-operation for poor responders. The use of FDG-PET/CT and diffusion-weighted magnetic resonance imaging for response prediction before, during and after preoperative chemoradiotherapy for rectal cancer Downstaging After Chemoradiotherapy for Locally Advanced Rectal Cancer: Is There More (Tumor) Than Meets the Eye?
Faced with the responsibility of treating patients with invasive distal rectal cancer who were medically unacceptable for the indicated radical surgery  , a prospect i ve study was initiated in which high dose preoperative radiation and full-thickness local excision were used . High dose preoperative radiation permitted full-thickness local excision of select cancers , which , by conventional st and ards , otherwise would have required radical surgery and permanent colostomy . Feasibility was measured on the basis of safety of the technique , control of the cancer , and the quality of anal sphincter function expected . Patients were selected initially because of their predicted inability to tolerate radical surgery , but indications were broadened to include those whose tumors had completely disappeared after irradiation . From 1984 to 1988 , 20 patients underwent 21 operative procedures for cancers located between 0 and 7 cm from the anorectal ring . This report is concerned with the 14 patients of this group who were observed for a minimum of 24 months .  High-dose preoperative radiation was administered for a total dose of 4500 cGy . Excision and repair were performed 4 to 6 weeks after completion of radiation therapy . Full-thickness disc or hemicircumferential excision was accomplished by transanal , transsphincteric , and transsacral techniques , which included , in several instances , excision of the sphincter mechanism and perineal body , and /or the vaginal wall . Full-thickness local excision after high-dose radiation therapy for rectal cancers has never been reported . Follow-up observation ranged from 24 to 48 months with a median of 31 months . Rectal reservoir function and sphincter control were good in 13 patients .  Local recurrence developed in three patients ( 21 percent ) , two of whom had postradiation therapy B2 mucinous cancers .  Three-year actuarial rate of local recurrence is 23 percent . One ( 7 percent ) patient died of recurrent disease . Actuarial Kaplan-Meier survival at 3 years is 61 percent . Based on the results of this small , select patient group , high-dose radiation therapy followed by full-thickness local excision appears to be a reasonable option for patients who can not tolerate radical surgery . This bimodal approach also may serve as an option for those who aregoodmedical risks , but for whom sphincter preservation is at stake , and to whom radical surgery offers limited benefits Background The aim of this study was to evaluate the clinical implication s of pathologic complete response ( pCR ) ( i.e. , T0N0M0 ) after neoadjuvant chemoradiation and radical surgery in patients with locally advanced rectal cancer . Material s and Methods A single-center , prospect ively maintained colorectal cancer data base was queried for patients with primary cII and cIII rectal cancer staged by CT and ERUS/MRI undergoing long-course neoadjuvant chemoradiation followed by proctectomy with curative intent between 1997 and 2007 . Patients were stratified into pCR and no-pCR groups and compared with respect to demographics , tumor and treatment characteristics , and oncologic outcomes . Outcomes evaluated were 5-year overall survival , disease-free survival , disease-specific mortality , local recurrence , and distant recurrence . Results The query returned 238 patients ( 73 % male ) , with a median age of 57 years and median follow-up of 54 months . Of these , 58 patients achieved pCR . Patients with pCR vs no-pCR were statistically comparable with respect to demographics , chemoradiation regimens , tumor distance from anal verge , clinical stage , surgical procedures performed , and follow-up time . No patient with pCR had local recurrence . Overall survival and distant recurrence were also significantly improved for patients achieving pCR . Conclusions Achievement of pCR after neoadjuvant chemoradiation is associated with greatly improved cancer outcomes in locally advanced rectal cancer . Future studies should evaluate the relationship between increases in pCR rates and improvements in cancer outcomes in this population Objective : To determine whether extending the interval between chemoradiation ( CRT ) and surgery , and administering additional chemotherapy during the waiting period has an impact on tumor response , CRT-related toxicity and surgical complications in patients with advanced rectal cancer . Background : Locally advanced rectal cancer is usually treated with preoperative CRT followed by surgery approximately 6 weeks later . The Timing of Rectal Cancer Response to Chemoradiation Consortium design ed a prospect i ve , multicenter , Phase II clinical trial to investigate extending the interval between CRT and surgery , and administering additional chemotherapy during the waiting period . Here , we present preliminary results of this trial , reporting the tumor response , CRT-related toxicity and surgical complications . Methods : Stage II and III rectal cancer patients were treated concurrently with 5-Fluorouracil ( FU ) and radiation for 5 to 6 weeks . Patients in study group ( SG ) 1 underwent total mesorectal excision ( TME ) 6 weeks later . Patients in SG2 with evidence of a clinical response 4 weeks after CRT received 2 cycles of modified FOLFOX-6 ( mFOLFOX-6 ) followed by TME 3 to 5 weeks later . Tumor response , CRT-related toxicity and surgical complications were recorded . Results : One hundred and forty-four patients were accrued . One hundred and thirty-six ( 66 , SG1 ; 70 , SG2 ) were evaluated for CRT-related toxicity . One hundred and twenty-seven ( 60 , SG1 ; 67 , SG2 ) were assessed for tumor response and surgical complications . A similar proportion of patients completed CRT per protocol in both SGs , but the cumulative dose of sensitizing 5-FU and radiation was higher in SG2 . CRT-related toxicity was comparable between SGs . Average time from CRT-to-surgery was 6 ( SG1 ) and 11 weeks ( SG2 ) . Pathologic complete response ( pCR ) was 18 % ( SG1 ) and 25 % ( SG2 ) . Postoperative complications were similar between SGs . Conclusions : Intense neoadjuvant therapy consisting of CRT followed by additional chemotherapy ( mFOLFOX-6 ) , and delaying surgery may result in a modest increase in pCR rate without increasing complications in patients undergoing TME for locally advanced rectal cancer Background This study aim ed to compare the oncologic results for local excision via transanal endoscopic microsurgery ( TEM ) and those for laparoscopic resection ( LR ) via total mesorectal excision in the treatment of T2 N0 , G1 - 2 rectal cancer after neoadjuvant therapy with both treatments , incorporating a 5-year minimum follow-up period . Methods The study enrolled 70 patients whose malignancy was staged at admission as T2 N0 , G1 - 2 rectal cancer located within 6 cm of the anal verge with a tumor diameter less than 3 cm . Of these patients , 35 were r and omized to TEM and 35 to LR . The patients in both groups previously had undergone high-dose radiotherapy ( 5,040 cGy in 28 fractions over 5 weeks ) combined with continuous infusion of 5-flurouracil ( 200 mg/m2/day ) . Results The median follow-up period was 84 months ( range , 72–96 months ) . Two local recurrences ( 5.7 % ) were observed after TEM and 1 ( 2.8 % ) after  LR . Distant metastases ( 2.8 % ) occurred in one case each after TEM and LR .  The probability of survival for rectal cancer was 94 % for TEM and 94 % for LR . Conclusions The study shows similar results between the two treatments in terms of local recurrences , distant metastases , and probability of survival for rectal cancer Purpose Prediction of rectal cancer response to preoperative , neo-adjuvant chemo-radiation therapy ( CRT ) provides the opportunity to identify patients in whom a major response is expected and who may therefore benefit from alternative surgical approaches . Traditional morphological imaging techniques are effective in defining tumour extension in the initial diagnostic and staging work-up , but perform poorly in distinguishing residual neoplastic tissue from scarring post CRT , when restaging the patient before surgery . Fluorine-18 fluorodeoxyglucose positron emission tomography ( FDG-PET ) is a promising tool for monitoring the effect of anti-tumour therapy . The aim of this study was to prospect ively assess the value of sequential FDG-PET scans in predicting the response of locally advanced rectal cancer to neo-adjuvant CRT . Methods Forty-four consecutive patients with locally advanced ( cT3–4 ) primary rectal cancer and four patients with pelvic recurrence of rectal cancer were enrolled in this prospect i ve study . Treatment consisted of external beam intensified radiotherapy ( 50 Gy to the posterior pelvis , 56 Gy to the tumour ) , chemotherapy ( in most cases PVI 5-FU at 300 mg/m2 per day ) and , 8–10 weeks later , surgery with curative intent . All patients underwent FDG-PET/CT both before CRT and 5–6 weeks after completing CRT . One patient died before surgery because of acute myocardial infa rct ion , and was therefore excluded from further analysis . Semi-quantitative measurements of FDG uptake ( SUVmax ) , absolute difference ( ΔSUVmax ) and percent SUVmax difference ( Response Index , RI ) between pre- and post-CRT PET scans were considered . Results were correlated with pathological response , assessed both by histopathological staging of the surgical specimens ( pTNM ) and by the tumour regression grade ( TRG ) according to M and ard ’s criteria ( patients with TRG1–2 being defined as responders and patients with TRG3–5 as non-responders ) . Results Following neo-adjuvant CRT , of the 45 patients su bmi tted to surgery , 23 ( 51.1 % ) were classified as responders according to M and ard ’s criteria ( 8 TRG1 and 15 TRG2 ) , while the remaining 22 ( 48.9 % ) were non-responders ( 9 TRG3 and 13 TRG4–5 ) . Considering all patients , the mean pre-CRT SUVmax was 15.6 , significantly higher than the mean value of 5.4 post CRT ( p < 0.001 ) . Nevertheless , when stratifying patients according to response to CRT ( using M and ard ’s criteria ) , the mean RI was significantly higher in responders than in non-responders ( 75.9 % versus 46.9%,p = 0.0015 ) . Using a 66.2 % SUVmax decrease as the cut-off value ( identified by ROC analysis ) for defining response to therapy , the following parameters were obtained : 79.2 % specificity , 81.2 % sensitivity , 77 % positive predictive value , 89 % negative predictive value and 80 % overall accuracy . Conclusion The results suggest the potential utility of FDG-PET as a complementary diagnostic and prognostic procedure in the assessment of neo-adjuvant CRT response of locally advanced rectal cancer . ΔSUVmax and RI seem the best predictors of CRT response Accurate response assessment after neoadjuvant therapy is essential in patients with rectal cancer . The aim of this study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography ( FDG-PET ) in predicting response of locally advanced rectal cancer to preoperative multimodal treatment . Twenty-two consecutive patients with locally advanced ( uT3/4 ) primary rectal cancer were entered in this prospect i ve pilot study . FDG-PET was performed before and after neoadjuvant radiochemotherapy ( RCT ) with combined regional hyperthermia ( RHT ) . Treatment consisted of external-beam radiotherapy ( 45 Gy ) , chemotherapy ( folinic acid and 5-fluorouracil ) and regional pelvic hyperthermia followed by curative tumour resection 6–8 weeks later . Semi-quantitative measurements ( SUV ) of tumour FDG uptake were made before and 2–4 weeks after completion of neoadjuvant treatment . Two patients who did not receive post-therapeutic restaging by FDG-PET were excluded from the analysis . Results were correlated with findings on endorectal ultrasound ( EUS , n=17 patients ) and histopathology . Histopathological evaluation of the resected tumour revealed complete response in one patient , partial response in 12 and stable disease in seven . SUV reduction in tumours was significantly greater in responders than in non-responders [ 60 % ( ±15 % ) vs 30 % ( ±18 % ) , P=0.003 , CI=95 % ) . Using a minimum post-therapeutic SUV reduction of 36 % to define response , FDG-PET revealed a sensitivity of 100 % ( EUS : 33 % ) and a specificity of 86 % ( EUS : 80 % ) in response prediction ; the corresponding positive and negative predictive values were 93 % ( EUS : 80 % ) and 100 % ( EUS : 33 % ) , respectively . FDG-PET results were statistically significant ( P<0.001 , CI=95 % ) . FDG-PET has great potential in the assessment of tumour response to neoadjuvant RCT in combination with RHT and is superior to EUS for this purpose PURPOSE To develop a positron emission tomography (PET)-based response prediction model to differentiate pathological responders from nonresponders . The predictive strength of the model was vali date d in a second patient group , treated and imaged identical to the patients on which the predictive model was based . METHODS AND MATERIAL S Fifty-one rectal cancer patients were prospect ively included in this study . All patients underwent fluorodeoxyglucose ( FDG ) PET-computed tomography ( CT ) imaging both before the start of chemoradiotherapy ( CRT ) and after 2 weeks of treatment . Preoperative treatment with CRT was followed by a total mesorectal excision . From the resected specimen , the tumor regression grade ( TRG ) was scored according to the M and ard criteria . From one patient group ( n = 30 ) , the metabolic treatment response was correlated with the pathological treatment response , result ing in a receiver operating characteristic ( ROC ) curve based cutoff value for the reduction of maximum st and ardized uptake value ( SUV(max ) ) within the tumor to differentiate pathological responders ( TRG 1 - 2 ) from nonresponders ( TRG 3 - 5 ) . The applicability of the selected cutoff value for new patients was vali date d in a second patient group ( n = 21 ) . RESULTS When correlating the metabolic and pathological treatment response for the first patient group using ROC curve analysis ( area under the curve = 0.98 ) , a cutoff value of 48 % SUV(max ) reduction was selected to differentiate pathological responders from nonresponders ( specificity of 100 % , sensitivity of 64 % ) . Applying this cutoff value to the second patient group result ed in a specificity and sensitivity of , respectively , 93 % and 83 % , with only one of the pathological nonresponders being false positively predicted as pathological responding . CONCLUSIONS For rectal cancer , an accurate PET-based prediction of the pathological treatment response is feasible already after 2 weeks of CRT . The presented predictive model could be used to select patients to be considered for less invasive surgical interventions or even a " wait and see " policy . Also , based on the predicted response , early modifications of the treatment protocol are possible , which might result in an improved clinical outcome BACKGROUND This study was conducted to assess the efficacy of preoperative chemoradiation followed by transanal excision among patients with locally advanced lower rectal cancer . METHODS Between May 1994 and June 2005 , 73 patients with locally advanced lower rectal cancer were treated with curative intent by preoperative chemoradiation followed by surgical resection . Transanal excision was performed in 9 patients due to either the absolute refusal of a permanent stoma by the patient ( n = 8) or medical comorbidity ( n = 1 ) . Sixty-four patients were treated by radical proctectomy . Preoperative 5-fluorouracil-based chemotherapy and pelvic radiation ( 4500 to 5040 cGy ) were followed by surgery 6 wk after treatment , and all patients except one with transanal excision received postoperative 5-fluorouracil-based chemotherapy during the first year after surgery . RESULTS The mean follow-up period was 91 mo ( range , 50 to 127 mo ) ; median follow-up was 94 mo . One local recurrence occurred at 30 mo after transanal excision ( 11.1 % ) ; 5 in 64 patients who received radical proctectomy ( 7.8 % ) experienced local recurrences . The disease-free survival rate at 10 y was 77.8 % in transanal excision group compared with a rate of 62.7 % among radical proctectomy patients ( P = 0.335 ) . The overall survival rate at 10 y was 88.9 % in transanal excision group compared with 74.2 % among radical proctectomy patients ( P = 0.424 ) . CONCLUSIONS Transanal excision after preoperative chemoradiation in highly-selected patients with locally advanced lower rectal cancer could probably be an acceptable alternative to conventional radical surgery . However , this approach should be prospect ively vali date d , and strict patient selection criteria should be used PURPOSE To determine whether changes in apparent diffusion coefficients ( ADCs ) of rectal carcinoma obtained 1 week after the beginning of chemotherapy and radiation therapy ( CRT ) correlate with tumor histopathologic downstaging after preoperative CRT . MATERIAL S AND METHODS This prospect i ve study was approved by an institutional review board ; informed consent was obtained from all patients . Thirty-seven patients ( mean age , 54.7 years ; 13 women , 24 men ) with primary rectal carcinoma who were undergoing preoperative CRT were recruited for the study . Diffusion-weighted ( DW ) magnetic resonance ( MR ) imaging was performed with a 1.5-T MR imager in all patients before therapy , at the end of the 1st and 2nd week of therapy , and before surgery . Tumor ADCs were calculated . Linear mixed-effects modeling was applied to analyze change in ADCs and volumes following treatment . RESULTS Patients were assigned to the tumor downstaged group ( n = 17 ) or the tumor nondownstaged group ( n = 20 ) on the basis of histopathologic examination results following surgery . Before CRT , the mean tumor ADC in the downstaged group was lower than that in the nondownstaged group ( 1.07 x 10(-3 ) mm(2)/sec + /- 0.13 [ st and ard deviation ] vs 1.19 x 10(-3 ) mm(2)/sec + /- 0.15 , F = 6.91 , P = .013 ) . At the end of the 1st week of CRT , the mean tumor ADC increased significantly from 1.07 x 10(-3 ) mm(2)/sec + /- 0.13 to 1.32 x 10(-3 ) mm(2)/sec + /- 0.16 ( F = 37.63 , P < .001 ) in the downstaged group , but there was no significant ADC increase in the nondownstaged group ( F = 1.18 , P = .291 ) . The mean percentage of tumor ADC change in the downstaged group was significantly higher than that in the nondownstaged group at each time point ( F = 18.39 , P < .001 ) . CONCLUSION Early increase of mean tumor ADC and low pretherapy mean ADC in rectal carcinoma correlate with good response to CRT . DW MR imaging is a promising noninvasive technique for helping predict and monitor early therapeutic response in patients with rectal carcinoma who are undergoing CRT Multimodality treatment of loco-regional advanced rectal cancer has demonstrated to improve local control and overall survival .  Proctoscopy , digital rectal examination ( DRE ) , computer tomography ( CT ) , endorectal ultrasound ( ERUS ) , and magnetic resonance imaging ( MRI ) can not correctly detect downstaging in rectal tumors after chemo radiation therapy ( CRT ) . New imaging techniques , like 18F-FDG PET , may play some role in predicting the pathologic response to CRT before surgical resection . Aim of the present study was to further investigate the accuracy and predictive value of 18F-FDG PET in a large series of patients with rectal cancer treated with preoperative intensified CRT . Between January 2000 and December 2003 , 81 patients with histologically proven adenocarcinoma in clinical stage II-III disease , according to criteria of TNM classification , were included in this study . All patients were su bmi tted to diagnostic staging workup with DRE , proctoscopy with biopsy , ERUS , CT scan of the abdomen and pelvis or pelvic MRI plus liver ultrasonography , coloscopy or barium colonic enema . One month later the end of CRT all patients were su bmi tted to diagnostic restaging work-up ( DRW ) and 18F-FDG PET . Surgery was performed 8 - 9 weeks after the end of CRT and pathologic stage was defined . Moreover a pathologic assessment of tumor regression was made with tumor regression grade score ( TRG ) .  PET correctly identified 22/28 ( 79 % specificity ) patients with complete pathologic response ( pCR ) . However , sensitivity was 45 % ( 24/53 ) while PPV , and NPV were equal to 77 and 43 % , respectively . Total PET accuracy rate was 56 % . PET sensitivity increased from 45 to 56 % if the end-point was pCR , or TRG score , respectively . The best correlation was found between PET findings and pathologic stage ( P < 0.01 ) or TRG score ( P < 0.01 ) . The accurate identification of rectal cancer patients with major pathological response after preoperative CRT further supports the necessity of design ing prospect i ve studies with new and more accurate was imaging technologies with the main object of offering conservative treatment in responder patients PURPOSE To prospect ively differentiate , at magnetic resonance ( MR ) imaging , patients with locally advanced nonmucinous rectal cancer who will respond to long-course chemotherapy and radiation therapy ( CRT ) from those who will not respond , with histopathologic results as the reference st and ard . MATERIAL S AND METHODS Institutional review board approval for this study was obtained , and all patients provided written informed consent . High-spatial-resolution T2-weighted MR images were acquired before and 6 - 8 weeks after CRT in 53 patients ( 33 men , 20 women ; mean age , 63 years ; age range , 42 - 79 years ) . Patients were categorized as responders to CRT ( patients with T3 cancer that converted to T2 or a lower stage , patients with T4 cancer that converted to T3 or a lower stage ) or as nonresponders ( patients with stable or progressive disease ) . At the posttreatment MR imaging examination , a decrease in signal intensity was considered to represent a morphologic response with fibrosis . Before CRT and surgery , tumor volume was calculated at MR imaging by multiplying cross-sectional area by section thickness . Tumor length was measured at MR imaging and in the histopathologic specimen . Nodal downstaging was evaluated . The relationship between pathologic response , morphologic MR imaging response , and percentage volume reduction was evaluated with the Mann-Whitney-Wilcoxon two- sample test . RESULTS Morphologic response assessment with MR imaging achieved a positive predictive value ( PPV ) of 84.2 % ( 32 of 38 ) and a negative predictive value ( NPV ) of 66.7 % ( 10 of 15 ) . Volume reduction extent ( > or = 70 % ) was significantly different between patients in whom disease was downstaged and those in whom it was not downstaged ( P = .000005 ) and showed additional diagnostic value , with an overall accuracy of 86.8 % ( 46 of 53 ) . Presurgical MR imaging and histopathologic tumor length did not show a significant difference . MR imaging accuracy for lymph node ( N ) stage was 86.8 % ( 46 of 53 ) on the basis of morphologic criteria . CONCLUSION After CRT , morphologic and volumetric evaluation at MR imaging had a high PPV and a low NPV for response assessment . The detection of small clusters of residual tumor cells within fibrosis remains a problem . SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/250/3/730/DC1 PURPOSE To correlate changes in 2-deoxy-2-[18F]fluoro-d-glucose ( 18-FDG ) positron emission tomography ( PET ) ( 18-FDG-PET ) uptake with response and disease-free survival with combined modality neoadjuvant therapy in patients with locally advanced rectal cancer . METHODS AND MATERIAL S Charts were review ed for consecutive patients with ultrasound-staged T3x to T4Nx or TxN1 rectal adenocarcinoma who underwent preoperative chemoradiation therapy at Fox Chase Cancer Center ( FCCC ) or Robert H. Lurie Comprehensive Cancer Center of Northwestern University with 18-FDG-PET scanning before and after combined-modality neoadjuvant chemoradiation therapy .  The maximum st and ardized uptake value ( SUV ) was measured from the tumor before and 3 to 4 weeks after completion of chemoradiation therapy preoperatively . Logistic regression was used to analyze the association of pretreatment SUV , posttreatment SUV , and % SUV decrease on pathologic complete response ( pCR ) , and a Cox model was fitted to analyze disease-free survival . RESULTS A total of 53 patients ( FCCC , n = 41 , RLCCC , n = 12 ) underwent pre- and postchemoradiation PET scanning  between September 2000 and June 2006 . The pCR rate was 31 % . Univariate analysis revealed that % SUV decrease showed a marginally trend in predicting pCR ( p = 0.08 ) . In the multivariable analysis , posttreatment SUV was shown a predictor of pCR ( p = 0.07 ) , but the test results did not reach statistical significance . None of the investigated variables were predictive of disease-free survival . CONCLUSIONS A trend was observed for % SUV decrease and posttreatment SUV predicting pCR in patients with rectal cancer treated with preoperative chemoradiation therapy .  Further prospect i ve study with a larger sample size is warranted to better characterize the role of 18-FDG-PET for response prediction in patients with rectal cancer BACKGROUND Patients with transmural or node-positive rectal cancer benefit from the addition of chemoradiation to surgical resection . Administration of the chemoradiation ( combined modality therapy ) preoperatively has gained popularity in recent years . Some patients undergo apparent complete tumor regression after preoperative combined modality therapy , and controversy exists about the proper management of these patients . Some investigators have proposed that such patients should simply be observed and not undergo resection . STUDY DESIGN The purpose of this study was to determine the significance of clinical complete response to preoperative combined modality therapy . Specifically , we have attempted to determine the frequency with which a clinical complete response ( based on the absence of detectable tumor on preoperative digital rectal examination and proctoscopy ) correlates with a pathologic complete response ( based on the absence of cancer cells in the resected specimen ) . A retrospective review of the clinical and pathologic characteristics of 488 patients from the Memorial Sloan-Kettering prospect i ve colorectal data base who received preoperative chemoradiation followed by resection for primary rectal cancer was performed . The indications for preoperative therapy included clinical or ultrasound T3 or T4 tumors or node-positive disease . RESULTS The clinical complete response rate to preoperative therapy was 19 % . All patients underwent resection subsequent to preoperative therapy regardless of response . The pathologic complete response rate among all patients was 10 % . The pathologic complete response rate among clinical complete responders was 25 % . Clinical complete response was a significant predictive factor for pathologic complete response , but the majority ( 75 % ) of clinical complete responders had persistent foci of tumor that were not detectable on preoperative examination or proctoscopy . CONCLUSIONS Clinical complete response to preoperative therapy as determined by preoperative digital rectal examination and proctoscopy or EUA is not an accurate predictor of pathologic complete response . A significant percentage of clinical complete responders have persistent deep tumors or nodal involvement . We do not recommend making treatment decisions based solely on the absence of clinical ly palpable or visible tumor after chemoradiation . Our data suggest that all acceptable-risk patients with a diagnosis of primary rectal cancer should undergo resection , regardless of their response to preoperative therapy PURPOSE Clinical assessment of rectal cancer response to preoperative combined-modality therapy ( CMT ) using digital rectal examination ( DRE ) has been proposed as a means of assessing efficacy of therapy . However , because the accuracy of this approach has not been established , we conducted a prospect i ve analysis to determine the operating surgeon 's ability to assess response using DRE . PATIENTS AND METHODS Ninety-four prospect ively accrued patients with locally advanced rectal cancer ( T3/4 or N1 ) were evaluated with  DRE and sigmoidoscopy  in order to determine the following tumor characteristics : size , location , mobility , morphology , and circumference . Following preoperative CMT ( 50.40 Gy with fluorouracil-based chemotherapy ) and under general anesthesia , the same surgeon estimated tumor response based on changes in these tumor characteristics , assessed via DRE . Percent pathologic tumor response was determined prospect ively by a single pathologist using whole mount sections of the resected cancer . RESULTS Clinical assessment using DRE underestimated pathologic response in 73 cases ( 78 % ) . In addition , DRE was able to identify only 3 of 14 cases ( 21 % ) with a pathologic complete response . There were no clinical overestimates of response . None of the clinicopathologic tumor characteristics examined had a significant impact on DRE estimation of response . CONCLUSION Clinical examination underestimates the extent of rectal cancer response to preoperative CMT . Given the inaccuracy of DRE following preoperative CMT , it should not be used as a sole means of assessing efficacy of therapy nor for selecting patients following CMT for local surgical therapies BACKGROUND AND PURPOSE To report an early analysis of prospect i ve study exploring preoperative radiotherapy and local excision in rectal cancer . MATERIAL S AND METHODS Mucosa at tumour edges was tattooed . Patients with cT1 - 3N0 tumour < 3 - 4 cm were treated with either 5x5Gy+4Gy boost ( N=31 ) or chemoradiation ( 50.4Gy+5.4Gy boost , 1.8Gy per fraction+5-fluorouracyl and leucovorin ; N=13 ) . Thirteen patients from the short-course group were unfit for chemotherapy .  The interval from radiation to full-thickness local excision was 6 weeks . The protocol called for conversion to a transabdominal surgery in case of ypT2 - 3 disease or positive margin . RESULTS The postoperative complications requiring hospitalization were recorded in 9 % of patients . The rate of pathological complete response was 41 % . The rate of patients requiring conversion was 34 % ; however , 18 % actually underwent conversion and the remaining 16 % refused or were unfit . During the 14 months of median follow-up , local recurrence was detected in 7 % of patients and all underwent salvage surgery . Of 19 patients in whom initially anterior resection was likely , 16 % had abdominoperineal resection performed for a conversion or as a rescue procedure . CONCLUSION Our study suggests that the short-course radiation prior to local excision is a treatment option for high-risk patients Abstract Purpose . To investigate the use of FDG-PET/CT before , during and after chemoradiotherapy ( CRT ) and diffusion-weighted magnetic resonance imaging ( DW-MRI ) before CRT for the prediction of pathological response ( pCR ) in rectal cancer patients . Material and methods . Twenty-two rectal cancer patients treated with long course CRT were included . An FDG-PET/CT was performed prior to the start of CRT , after 10 to 12 fractions of CRT and five weeks after the end of CRT . The tumor was delineated using a gradient based delineation method and the maximal st and ardized uptake values ( SUVmax ) were calculated . A DW-MRI was performed before start of CRT . Mean apparent diffusion coefficients ( ADC ) were determined . The ΔSUVmax during and after CRT and the initial ADC values were correlated to the histopathological findings after total mesorectal excision ( TME ) . Results . ΔSUVmax during and after CRT significantly correlated with the pathological response to treatment ( during CRT : ΔSUVmax = 59 % ± 12 % for pCR vs. 25 % ± 27 % if no pCR , p=0.0036 ; post-CRT : 90 % ± 11 for pCR vs. 63 % ± 22 if no pCR p=0.013 ) . ROC curve analysis revealed an optimal threshold for ΔSUVmax of 40 % during CRT and 76 % after CRT . The initial ADC value was also significantly correlated with pCR ( 0.94 ± 0.12 × 10−3 mm2/s for pCR vs. 1.2 ± 0.24 × 10−3 mm2/s , p=0.002 ) and ROC curve analysis revealed an optimal threshold of 1.06 × 10−3 mm2/s . Combining the provided ΔSUVmax thresholds during and after CRT increased specificity of the prediction ( sensitivity 100 % and specificity 94 % ) . The combination of the thresholds for the initial ADC value and the ΔSUVmax during CRT increased specificity of the prediction to a similar level ( sensitivity of 100 % and specificity of 94 % ) . Conclusions . The combination of the different time points and the different imaging modalities increased the specificity of the response assessment both during and after CRT PURPOSE : Preoperative chemoradiotherapy can lead to pathologic complete response of rectal cancer . This study was design ed to determine the relationship between postchemoradiotherapy pathologic T stage ( ypT stage ) and nodal metastases and to evaluate whether pathologic complete response of the primary tumor results in sterilization of mesorectal lymph nodes . METHODS : Clinicopathological data from 1997 to 2007 of a prospect ively maintained colorectal cancer data base were examined . Inclusion criteria were patients with extraperitoneal rectal cancer who underwent preoperative chemoradiotherapy and subsequent radical resection .  Statistical analysis was performed by use of Kruskall-Wallis and Wilcoxon rank-sum tests . RESULTS : Two hundred forty-two patients were identified ( 73.1 % male , median age , 57 y ( range , 36–85 y ) ) . Data regarding preoperative chemoradiotherapy were available for 177 patients ( 73.1 % ) . The median dose of radiotherapy was 5040 cGy ( 3060–6100 cGy ) . The mean preoperative radiotherapy dose and interval between chemoradiotherapy and surgery are similar when stratified by ypT stage ( P = .55 and P = .72 , respectively ) . Low anterior resection was performed in 174 patients ( 71.6 % ) , and the remainder underwent abdominoperineal resection . A mural pathologic complete response was achieved in 62 patients ( 25.6 % ) . In this pathologic complete-response group , positive lymph nodes were found in 2 patients ( 3.2 % ) . The rate of metastatic lymph nodes increased as ypT stage increased ( ypT1 = 11.1 % , ypT2 = 29.2 % , ypT3 = 37.3 % ) . CONCLUSION : Patients with a mural pathologic complete response  have a low rate of positive lymph nodes . These findings may have implication s for the management strategies of these patients , including the use of local resection or a watch- and -wait policy . When the response to chemoradiotherapy is not complete , radical surgery should remain the treatment based on high rates of lymph node involvement
BACKGROUND In this modern era of multi-modality treatment there is increasing interest in the possibility of avoiding radical surgery in complete responders after neo-adjuvant long-course chemoradiotherapy ( LCPRT ) .
In this article , we present a systematic review of such treatments and discuss their therapeutic applicability for the future .