Radiation therapy involves the delivery of high-energy beams that are targeted directly at the tumour of a patient. Radiation from external beams is known as external beam radiation.
The treatment of brachytherapy is different. Small pieces of radioactive material (usually the size of a grain of rice) are placed inside the patient's body as close to the tumour as possible for radiation therapy. It allows doctors to deliver high doses of radiation directly to the tumour while limiting the exposure of healthy tissue to radiation.
Using brachytherapy is a standard treatment for many gynecologic cancers, including cervical, uterine and vaginal cancers. Brachytherapy is a common treatment for cervical cancer patients following external beam radiation. Patients with uterine cancer who cannot undergo surgery may also receive brachytherapy, and some patients with endometrial cancer will receive brachytherapy following surgery.
Gynecologic brachytherapy begins with general anaesthesia when a patient has never had surgery. As close as possible to the tumour, a radiation oncologist places an applicator inside the patient's vagina or uterus (depending on the type of cancer). It is imperative to note that advanced imaging technologies (such as MRIs, ultrasounds, and CT scans) assist in positioning the applicator so that the radiation dose is delivered most effectively and determining the actual dose.
An applicator is attached to a machine containing a radioactive pellet. In the applicator, the pellets are positioned in a predetermined position for a specific time to optimize radiation dose and coverage.
After a hysterectomy, brachytherapy is also used to treat endometrial cancer to eliminate any cancer cells that might remain. In this procedure, a vaginal applicator is placed in the vagina while the patient is awake. A high-dose brachytherapy source is connected to the applicator and radioactive source is advanced unto the applicator in a pre-determined position.
Although doctors take great care not to damage healthy tissue during brachytherapy for gynecologic cancers, there may be short-term side effects, such as soreness where the applicator was placed or minor bleeding. Radiation can cause diarrhoea and blood in the urine or stool over the long term. If these symptoms develop and do not improve with medication, your oncologist may refer you to a gastroenterologist or urologist for diagnosis or treatment.