The term “Brachy” is from the greek derivative meaning “short distance”. Thus, brachytherapy is a treatment where the source of radiation (typically, a radioactive seed) is placed within or adjacent to tissues at risk of harboring cancer cells. The treatment is very targeted and delivers a highly precise radiation dose only in close proximity to the source. When surgically placed within the body or organ, the radiation is delivered from the inside out thereby maximally sparing healthy nearby tissues.
3D HDR Brachytherapy
At the Precision Cancer Specialists, this minimally invasive procedure is often used to treat breast, gynecologic, lung, and skin cancers.
With this technique, a high dose rate (HDR) radioactive seed (Iridium 192) is attached to the end of a wire or cable. The wire is remotely placed inside or next to the tumor via a catheter or applicator that have previously been placed in the patient for a short amount of time, typically a few minutes to deliver the required radiation treatment dose. By electronically varying the seed position and time, the dose can be neatly sculpted to provide a dose geometry conforming to the shape of the target, while also preventing unnecessary radiation to surrounding tissues. A course of therapy can be completed in less time than other radiotherapy techniques, typically 1 to 5 days with minimal recovery time thereby allowing patients to get back to their everyday life sooner.
After a lumpectomy and sentinel node mapping procedure, the breast cancer pathology is carefully evaluated. If patients have favorable risk, in many cases a more focused area of the breast near the surgical site can be treated with accelerated partial breast irradiation or APBI with HDR brachytherapy. A customized catheter is placed into the lumpectomy cavity and a 3D treatment plan is designed to conformally irradiate the breast tissue at risk while maximally sparing the skin, normal breast, ribs, lungs and heart. The more limited volume allows the treatment to be performed in one week. Several studies have shown equivalent local control rates in favorable risk patients as an alternative to conventional six weeks of daily external beam radiation therapy.
HDR brachytherapy is often used after hysterectomy to decrease risk of vaginal recurrence in higher risk uterine cancer. It can be used for endobronchial treatment for lung cancer lesions that narrow the airways via placement of a brachytherapy catheter during bronchoscopy. Radiation therapy has been used as a noninvasive treatment alternative to Mohs surgery for basal cell and squamous cell skin cancer for decades. HDR brachytherapy is a precise method that can accomplish similar results to surgery in just 8-10 short visits.
At the Precision Cancer Specialists, this modality is used for prostate seeds and lung-mesh brachytherapy. In contrast to HDR brachytherapy, LDR or low dose rate is used for clinical scenarios where the radioactive seeds are placed permanently into the body and deliver their radiation dose slowly allowing normal tissues to heal in the process. The seeds become inactive after a few weeks.
Urologists and radiation oncologists perform prostate LDR brachytherapy in a minimally invasive, outpatient surgical procedure in which radioactive seeds typically made of Iodine 125, Palladium 103 or Cesium 131 are inserted into the prostate with ultrasound guidance. Long-term studies have shown equivalent outcomes to surgical removal of the prostate with fewer side effects in carefully selected low risk patients. For patients with higher risk disease, a prostate seed implant is typically combined with a few weeks of IMRT and/or anti-hormone therapy. This allows treatment to be directed at both the prostate gland, the seminal vesicles and lymph nodes where cancer cells may have spread. The simple procedure takes just under one hour from start to finish with most patients returning to normal activities within a few days.
For selected lung cancer patients, a more limited surgery or wedge resection may be able to be done as an alternative to a lobectomy (removal of a whole lobe of the lung). The highest risk area for recurrence is along the surgical staple or suture line. In this innovative technique, a customized radioactive mesh is sutured to the staple line during the surgical procedure. The more targeted treatment limits collateral radiation exposure to healthy parts of the body including the lung and heart. The radiation is delivered over a few weeks and the patient does not need to travel back and forth to the radiation facility. Several reports have demonstrated local control rates above 95% with this modality.