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 < or = 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.