Adjuvant whole abdominal irradiation in clinical stages I and II papillary serous or clear cell carcinoma of the endometrium: a phase II study of the Gynecologic Oncology Group.

Objectives: To evaluate outcome in patients with clinical stage I/II papillary serous (PS) or clear cell (CC) endometrial carcinoma treated with whole abdominal radiotherapy.
Methods: After total abdominal hysterectomy with bilateral salpingo-oophorectomy, pelvic/para-aortic lymph node sampling, and peritoneal washings, eligible patients received radiotherapy (RT) to the abdomen (3000 cGy at 150 cGy/day) with a pelvic boost (1980 cGy at 180 cGy/day).
Results: Among 21 PS patients (median age: 68 years), one refused therapy, and another received a non-protocol vaginal boost. In total, eight patients died of disease (DOD) between 9.6 and 35.2 months. Five others died due to protocol treatment (1), toxicity from subsequent chemotherapy (1), intercurrent disease (1), and unknown cause (2). Five-year progression-free survival (PFS) was 38%. Among treated patients who DOD, sites of recurrence included lung (2), lung/vagina (1), abdomen/pelvis (1), vagina (1), and abdomen (2). Among 13 CC patients (median age: 63 years), one received pelvic RT only and died with intercurrent disease. Five others died due to DOD (3), intercurrent disease (1), and unknown cause (1). Five-year PFS was 54%. Among patients who DOD, sites of recurrence included lung (1), vagina (1), and unknown (1). Grade 3/4 toxicities for both histologic groups included gastrointestinal (three grade 4; three grade 3), hematologic (one grade 4), and cutaneous (one grade 3).
Conclusions: Over half of the treatment failures were within the radiation field. Systemic chemotherapy, radiosensitizing chemotherapy, or sequential radiation and chemotherapy should be considered in future adjuvant trials for these patients.