For many forms of cancer, the term radiotherapy actually implies external beam irradiation, in which the radiation is directed at the tumor from an external source. For some cancers, however, brachytherapy is commonly used. In this method, a small radioactive pellet is implanted directly into the area of the cancer. The purpose is to obtain a high level of radiation which is relatively limited to the involved area and which minimizes the exposure of surrounding tissues. Brachytherapy is commonly used on gynecologic cancers, including cervical cancer, endometrial cancer, and cancer of the vagina. Because these cancers often affect elderly patients, it is important to consider not only the effectiveness of the treatment method but also the effects which the treatment itself has on the health and well-being of the patient. In this study, the effects of 462 instances of brachytherapy treatment on 327 patients with gynecologic cancer were reviewed. A total of 21 patients, or 6.4 percent, experienced some sort of potentially life-threatening complication. In 16 patients, these complications took the form of a heart attack, congestive heart failure, abnormal heartbeat patterns, or other complications involving the heart. Four patients developed thromboembolic complications, in which a blood clot formed and then blocked a blood vessel; in one such case, the blood vessel was in the lungs and the embolus resulted in death. In addition to this patient, four other patients died. Three patients died of heart attacks and one of heart failure resulting from pneumonia. Data analysis revealed that the patients who suffered life-threatening complications tended to be older on the average and were also likely to have had preexisting heart problems. The identification of patients who are at an especially high risk for complications of brachytherapy might be possible in advance, so that postoperative complications could be reduced by appropriate intensive care for the patients who need it most. (Consumer Summary produced by Reliance Medical Information, Inc.)