Radiotherapy in early ovarian cancer

Radiation therapy is an effective curative treatment modality in early ovarian cancer. A combination of the independent prognostic factors of grade, stage, and residual disease defines an "intermediate" risk group whose probability of long-term disease-free survival from abdomino-pelvic radiation therapy (APRT) is between 62 and 91%. This group in which abdomino-pelvic radiotherapy is recommended as the sole postoperative treatment is mainly constituted from patients with Stage II disease of all grades with no residuum or less than 2 cm residuum in the pelvis and selected optimal Stage III patients with low grade tumors. No therapy has been shown to benefit patients with Stage I grade 2 or 3 tumors, although relapse risks of 30% justify postoperative treatment in this group. APRT significantly reduced relapse risk in patients with Stages I and II disease, where tumors were densely adherent. The late toxicity of APRT is acceptable. When the abdominal dose is restricted to a total of 25 Gy and the pelvic dose to 45 Gy serious complications occur in less than 4% of patients. 32P, widely utilized in early-stage disease, has not been shown to be beneficial compared to cisplatin in a study of the Norwegian Radium Hospital. Its dosimetry precludes effective dosing of tumor at a depth of more than 1 to 2 mm from the peritoneal surface and of the retroperitoneal nodes. Its use should be abandoned. APRT is an effective anti-tumor modality in ovarian cancer and cannot be discarded. Further studies of this modality are justified. Its future exploitation lies in manipulations to increase the therapeutic ratio by either altered radiotherapy fractionation schemes and/or potential combination with radiation sensitizers.