brachytherapy brachytherapy brachytherapy is a form of radiation therapy where a sealed radiation source is placed inside or next to the area requiring treatment. brachy is greek for short. brachytherapy is commonly used as an effective treatment for cervical, prostate, breast, esophageal and skin cancer and can also be used to treat tumours in many other body sites. treatment results have demonstrated that the cancer-cure rates of brachytherapy are either comparable to surgery and external beam radiotherapy (ebrt) or are improved when used in combination with these techniques. brachytherapy can be used alone or in combination with other therapies such as surgery, ebrt and chemotherapy. brachytherapyarrow points to brachytherapy beads used to treat prostate cancer.other namesinternal radiotherapy, sealed source radiotherapy, curietherapy, endocurietherapyicd-10-pcsd?1icd-9-cm92.27meshd001918 brachytherapy contrasts with unsealed source radiotherapy, in which a therapeutic radionuclide (radioisotope) is injected into the body to chemically localize to the tissue requiring destruction. it also contrasts to external beam radiation therapy (ebrt), in which high-energy x-rays (or occasionally gamma-rays from a radioisotope like cobalt-60) are directed at the tumour from outside the body. brachytherapy instead involves the precise placement of short-range radiation-sources (radioisotopes, iodine-125 or cesium-131 for instance) directly at the site of the cancerous tumour. these are enclosed in a protective capsule or wire, which allows the ionizing radiation to escape to treat and kill surrounding tissue but prevents the charge of radioisotope from moving or dissolving in body fluids. the capsule may be removed later, or (with some radioisotopes) it may be allowed to remain in place.: ch. 1 a feature of brachytherapy is that the irradiation affects only a very localized area around the radiation sources. exposure to radiation of healthy tissues farther away from the sources is therefore reduced. in addition, if the patient moves or if there is any movement of the tumour within the body during treatment, the radiation sources retain their correct position in relation to the tumour. these characteristics of brachytherapy provide advantages over ebrt – the tumour can be treated with very high doses of localised radiation whilst reducing the probability of unnecessary damage to surrounding healthy tissues.: ch. 1 a course of brachytherapy can be completed in less time than other radiotherapy techniques. this can help reduce the chance for surviving cancer-cells to divide and grow in the intervals between each radiotherapy dose. patients typically have to make fewer visits to the radiotherapy clinic compared with ebrt, and may receive the treatment as outpatients. this makes treatment accessible and convenient for many patients. these features of brachytherapy mean that most patients are able to tolerate the brachytherapy procedure very well. the global market for brachytherapy reached us$680 million in 2013, of which the high-dose rate (hdr) and ldr segments accounted for 70%. microspheres and electronic brachytherapy comprised the remaining 30%. one analysis predicts that the brachytherapy market may reach over us$2.4 billion in 2030, growing by 8% annually, mainly driven by the microspheres market as well as electronic brachytherapy, which is gaining significant interest worldwide as a user-friendly technology. medical uses body sites in which brachytherapy can be used to treat cancer brachytherapy is commonly used to treat cancers of the cervix, prostate, breast, and skin. brachytherapy can also be used in the treatment of tumours of the brain, eye, head and neck region (lip, floor of mouth, tongue, nasopharynx and oropharynx), respiratory tract (trachea and bronchi), digestive tract (oesophagus, gall bladder, bile-ducts, rectum, anus), urinary tract (bladder, urethra, penis), female reproductive tract (uterus, vagina, vulva), and soft tissues. as the radiation sources can be precisely positioned at the tumour treatment site, brachytherapy enables a high dose of radiation to be applied to a small area. furthermore, because the radiation sources are placed in or next to the target tumour, the sources maintain their position in relation to the tumour when the patient moves or if there is any movement of the tumour within the body. therefore, the radiation sources remain accurately targeted. this enables clinicians to achieve a high level of dose conformity – i.e. ensuring the whole of the tumour receives an optimal level of radiation. it also reduces the risk of damage to healthy tissue, organs or structures around the tumour, thus enhancing the chance of cure and preservation of organ function. the use of hdr brachytherapy enables overall treatment times to be reduced compared with ebrt. patients receiving brachytherapy generally have to make fewer visits for radiotherapy compared with ebrt, and overall radiotherapy treatment plans can be completed in less time. many brachytherapy procedures are performed on an outpatient basis. this convenience may be particularly relevant for patients who have to work, older patients, or patients who live some distance from treatment centres, to ensure that they have access to radiotherapy treatment and adhere to treatment plans. shorter treatment times and outpatient procedures can also help improve the efficiency of radiotherapy clinics. brachytherapy can be used with the aim of curing the cancer in cases of small or locally advanced tumours, provided the cancer has not metastasized (spread to other parts of the body). in appropriately selected cases, brachytherapy for primary tumours often represents a comparable approach to surgery, achieving the same probability of cure and with similar side effects. however, in locally advanced tumours, surgery may not routinely provide the best chance of cure and is often not technically feasible to perform. in these cases radiotherapy, including brachytherapy, offers the only chance of cure. in more advanced disease stages, brachytherapy can be used as palliative treatment for symptom relief from pain and bleeding. in cases where the tumour is not easily accessible or is too large to ensure an optimal distribution of irradiation to the treatment area, brachytherapy can be combined with other treatments, such as ebrt and/or surgery.: ch. 1 combination therapy of brachytherapy exclusively with chemotherapy is rare. cervical cancer brachytherapy is commonly used in the treatment of early or locally confined cervical cancer and is a standard of care in many countries.: ch. 14 cervical cancer can be treated with either ldr, pdr or hdr brachytherapy. used in combination with ebrt, brachytherapy can provide better outcomes than ebrt alone. the precision of brachytherapy enables a high dose of targeted radiation to be delivered to the cervix, while minimising radiation exposure to adjacent tissues and organs. the chances of staying free of disease (disease-free survival) and of staying alive (overall survival) are similar for ldr, pdr and hdr treatments. however, a key advantage of hdr treatment is that each dose can be delivered on an outpatient basis with a short administration time providing greater convenience for many patients. research shows locally advanced carcinoma of the cervix must be treated with a combination of external beam radiotherapy (ebrt) and intracavity brachytherapy (icbt). prostate cancer main article: prostate brachytherapybrachytherapy to treat prostate cancer can be given either as permanent ldr seed implantation or as temporary hdr brachytherapy.: ch. 20 permanent seed implantation is suitable for patients with a localised tumour and good prognosis and has been shown to be a highly effective treatment to prevent the cancer from returning. the survival rate is similar to that found with ebrt or surgery (radical prostatectomy), but with fewer side effects such as impotence and incontinence. the procedure can be completed quickly and patients are usually able to go home on the same day of treatment and return to normal activities after one to two days. permanent seed implantation is often a less invasive treatment option compared to the surgical removal of the prostate. temporary hdr brachytherapy is a newer approach to treating prostate cancer, but is currently less common than seed implantation. it is predominantly used to provide an extra dose in addition to ebrt (known as "boost" therapy) as it offers an alternative method to deliver a high dose of radiation therapy that conforms to the shape of the tumour within the prostate, while sparing radiation exposure to surrounding tissues. hdr brachytherapy as a boost for prostate cancer also means that the ebrt course can be shorter than when ebrt is used alone. breast cancer radiation therapy is standard of care for women who have undergone lumpectomy or mastectomy surgery, and is an integral component of breast-conserving therapy.: ch. 18 brachytherapy can be used after surgery, before chemotherapy or palliatively in the case of advanced disease. brachytherapy to treat breast cancer is usually performed with hdr temporary brachytherapy. post surgery, breast brachytherapy can be used as a "boost" following whole breast irradiation (wbi) using ebrt. more recently, brachytherapy alone is used to deliver apbi (accelerated partial breast irradiation), involving delivery of radiation to only the immediate region surrounding the original tumour. the main benefit of breast brachytherapy compared to whole breast irradiation is that a high dose of radiation can be precisely applied to the tumour while sparing radiation to healthy breast tissues and underlying structures such as the ribs and lungs. apbi can typically be completed over the course of a week. the option of brachytherapy may be particularly important in ensuring that working women, the elderly or women without easy access to a treatment centre, are able to benefit from breast-conserving therapy due to the short treatment course compared with wbi (which often requires more visits over the course of 1–2 months). there are five methods that can be used to deliver breast brachytherapy: interstitial breast brachytherapy, intracavitary breast brachytherapy, intraoperative radiation therapy, permanent breast seed implantation and non-invasive breast brachytherapy using mammography for target localization and an hdr source. interstitial breast brachytherapy interstitial breast brachytherapy involves the temporary placement of several flexible plastic catheters in the breast tissue. these are carefully positioned to allow optimal targeting of radiation to the treatment area while sparing the surrounding breast tissue. the catheters are connected to an afterloader, which delivers the planned radiation dose to the treatment area. interstitial breast brachytherapy can be used as "boost" after ebrt, or as apbi. intraoperative radiation therapy intraoperative radiation therapy (iort) delivers radiation at the same time as the surgery to remove the tumour (lumpectomy). an applicator is placed in the cavity left after tumour removal and a mobile electronic device generates radiation (either x-rays or electrons) and delivers it via the applicator. radiation is delivered all at once and the applicator removed before closing the incision. intracavitary breast brachytherapy intracavitary breast brachytherapy (also known as "balloon brachytherapy") involves the placement of a single catheter into the breast cavity left after the removal of the tumour (lumpectomy). the catheter can be placed at the time of the lumpectomy or postoperatively. via the catheter, a balloon is then inflated in the cavity. the catheter is then connected to an afterloader, which delivers the radiation dose through the catheter and into the balloon. currently, intracavitary breast brachytherapy is only routinely used for apbi. there are also devices that combine the features of interstitial and intracavitary breast brachytherapy (e.g. savi). these devices use multiple catheters but are inserted through a single-entry point in the breast. studies suggest the use of multiple catheters enables physicians to target the radiation more precisely. permanent breast seed implantation permanent breast seed implantation (pbsi) implants many radioactive "seeds" (small pellets) into the breast in the area surrounding the site of the tumour, similar to permanent seed prostate brachytherapy. the seeds are implanted in a single 1–2 hour procedure and deliver radiation over the following months as the radioactive material inside them decays. risk of radiation from the implants to others (e.g. partner/spouse) has been studied and found to be safe. brain tumors surgically targeted radiation therapy (start), branded as gammatile therapy, is a type of brachytherapy implant specifically designed for use inside the brain. gammatile is fda-cleared to treat newly diagnosed, operable malignant intracranial neoplasms (i.e., brain tumors) and operable recurrent intracranial neoplasms, including meningiomas, metastases, high-grade gliomas, and glioblastomas. in a clinical study, gammatile therapy improved local tumor control compared to previous same-site treatments without an increased risk of side effects. esophageal cancer for esophageal cancer radiation treatment, brachytherapy is one option for effective treatment, involves definitive radiotherapy (boost) or palliative treatments. definitive radiotherapy (boost) can deliver the dose precisely and palliative treatments can be given to relieve dysphagia. the large diameter applicators or balloon type catheter are used with the afterloader to expand the esophagus and facilitate the delivery