In light of PORTEC-3 and GOG 249 data, do you use adjuvant radiation therapy alone in stage Ib serous endometrial carcinoma?

PORTEC-3 assigned women with high risk stage I or stage II-III endometrial carcinoma to adjuvant external beam radiation vs adjuvant chemoradiation with cisplatin followed by 4 cycles of carboplatin AUC5 + Taxol. Both groups received brachytherapy if warranted. Failure-free survival was improved in the chemotherapy group, particularly for stage III patients. Overall survival was not significantly different in the two arms, but favored chemoradiation + chemotherapy. The authors concluded that adjuvant chemoradiation followed by chemotherapy is recommended for stage III disease but could not be recommended for patients with stage I-II disease. GOG 249 assigned women with stage I or II endometrial cancer to either external beam radiation therapy +/- brachytherapy vs brachytherapy + 3 cycles of carboplatin AUC6 + Taxol. 35% of patients in the radiation-only arm received brachytherapy. Nodal recurrence rates were higher in the brachy + chemo group. The authors concluded that external beam radiation therapy should remain standard for patients with stage I-II endometrial cancer.