Improved outcome at 10 years for serous-papillary/clear cell or high-risk endometrial cancer patients treated by adjuvant high-dose whole abdomino-pelvic irradiation.

Purpose: The aim of the study was to evaluate the 10-year treatment outcome of utilizing adjuvant high-dose whole abdominal irradiation (WAPI technique) with a pelvic/vaginal boost in patients with stage I-III endometrial carcinoma at high risk for intra-abdominopelvic recurrence, including serous-papillary and clear cell histologies.

Material And Methods: In a prospective nonrandomized trial, 132 patients were treated with adjuvant WAPI between November 1981 and October 2001. Forty-three patients (32%) were 1998 FIGO stage I-II and 89 (68%) were stage III. Pathological features included the following: 66 (52%) with deep myometrial invasion, 50 (38%) with positive peritoneal cytology, 89 (67%) with high-grade lesions, 25 (19%) with positive pelvic/para-aortic lymph nodes, and 58 (45%) with serous-papillary or clear cell histology.

Results: The mean follow up was 6.4 years (range 0.6-16.1). For the entire group, the 5- and 10-year cause-specific survival (CSS) was 77 and 72%, whereas the disease-free survival (DFS) was 55 and 45%. When stratified by histology the 5- and 10-year CSS for adenocarcinoma was 75 and 70%, while serous-papillary/clear cell was 80 and 74% (P = 0.314). The 5- and 10-year DFS for adenocarcinoma was 59 and 49%, whereas serous-papillary/clear cell was 49 and 38% (P = 0.563). For surgical stages I-II, the 5-year CSS was 83% for adenocarcinoma and 89% for serous-papillary (P = 0.353). For stage III, it was 73 and 62% (P = 0.318), respectively. Forty-six patients (35%) relapsed. The first site of failure was the abdomen/pelvis in 27/46 (59%). When stratified by histologic variant, 34% of patients with adenocarcinoma and 41% with serous-papillary developed recurrent disease. In multivariate regression analysis only advancing age was of prognostic significance for CSS (P = 0.025) and DFS (P = 0.026). Chronic grade 3/4 GI toxicity was seen in 14%, and 2% of patients developed grade 3 renal toxicity.

Conclusion: High-dose adjuvant WAPI is very effective treatment with excellent 10-year results for stage I-III endometrial carcinoma with risk factors for intra-abdominopelvic recurrence, including serous-papillary or clear cell histology. The low long-term complication rate with high CSS makes high-dose WAPI the treatment of choice for these patients with significant comorbidities.