Radiation Therapy for Ovarian Cancer
Radiotherapy, otherwise known as radiation therapy, is not a common treatment for ovarian cancer in the United States. This is because many women are diagnosed with late-stage cancers that have spread widely within the abdominal cavity.
To be effective, radiotherapy must include all cancer cells within the radiation field, and abdominal organs like the liver, kidneys, and small bowel may not be able to withstand the doses of radiation required to destroy all tumorous tissue. Yet if the ovarian cancer is confined to one or both ovaries without spread to abdominal organs or pelvic lymph nodes, radiotherapy may be an option.
Radiation may be used to kill cancer cells from a cyst that ruptures during surgical removal of an ovary, or it may be used to treat certain patients who appear cancer-free or who have only microscopic evidence of disease at second-look surgery. It is historically the treatment of choice for germ cell tumors known as dysgerminomas. However, recently it has been found that chemotherapy can cure a percentage of such patients.
Radiotherapy uses high-energy, ionizing radiation (e.g., gamma rays) to kill cancer cells. Radiotherapy can be delivered in two ways: (1) by a radiotherapy device, which is used outside of the body in a manner similar to that of an x-ray machine, and (2) by injection of a short-lived radioactive chemical (e.g., radioactive phosphorus) into the peritoneal cavity.
Because cancer cells usually multiply faster than most bodily tissues, they are especially affected by radiation, which prevents cell division and the formation of DNA (human genetic material). Yet the bodily tissues that also divide rapidlysuch as the lining of the digestive tract, hair, and skinare particularly vulnerable to radiotherapy.
The specific side effects of abdominal (injected) radiotherapy include: abdominal pain, nausea, diarrhea, inflammation of the peritoneum (tissue that lines the abdominal cavity), formation of abdominal adhesions (fibrous bands), obstruction of the small bowel, and lowered blood counts. If radiotherapy is applied externally by a radiotherapy device, side effects may include skin irritation, edema (swelling), and skin darkening at the treatment site.