Postoperative whole abdominal radiotherapy in clear cell adenocarcinoma of the ovary

Abstract Objectives. The aim of this study was to clarify the efficacy of postoperative whole abdominal radiotherapy (WAR) for ovarian clear cell adenocarcinoma (OCCA). Methods. Between 1996 and 2004, 16 patients with OCCA underwent initial debulking surgery and received postoperative WAR. Indications for WAR were as follows: OCCA, International Federation of Gynaecology and Obstetrics (FIGO) stage Ic–III, no macroscopic residual disease in the upper abdomen and residual disease in the pelvic cavity ≤2 cm. The planned WAR comprised external beam radiotherapy (EBRT) to the entire abdominal cavity with 22.0–24.0 Gy/22–24 fractions followed by EBRT to the pelvis with 23.4–21.6 Gy/12–13 fractions. Overall survival (OS) and disease-free survival (DFS) were compared with 12 historical control (HC) patients treated with initial debulking surgery followed by platinum-based chemotherapy. Results. The FIGO stage in the WAR group was stage Ic in 11 patients, stage II in 3, and stage III in 2. Fifteen of the 16 patients (94%) completed the planned WAR. Two patients developed radiation enterocolitis and required bowel surgery. Five-year OS and DFS in the WAR/HC group were 81.8%/33.3% and 81.2%/25.0% ( p =0.031 and p =0.006), respectively. Conclusions. This study suggests that postoperative WAR may be effective in selected patients with OCCA. Prospective randomized trials should be considered to assess postoperative WAR for OCCA.