The Use of Adjuvant Radiation Therapy by Members of the Society of Gynecologic Oncologists

Abstract & commentary

Synopsis: Complete surgical staging in endometrial cancer appears to decrease the recommendation for postoperative adjuvant radiation therapy.

Source: Naumann RW, et al. Gynecol Oncol 1999; 75:4-9.

Naumann and colleagues have reported the findings of a survey of the members of the Society of Gynecologic Oncologists to determine their attitudes about the use of adjuvant radiation therapy in women with endometrial cancer. Of the 767 listed members, 325 (42%) responded. Less than 20% of respondents recommended adjuvant radiation therapy in stage IA, grade 1 or 2, and stage IB, grade 1 endometrial cancer. Adjuvant radiation is recommended by 40-50% of respondents for women with stage IA, grade 3, and stage IB, grade 2 tumors. Most recommend adjuvant radiation for all women with greater than 50% myometrial invasion or grade 3 tumors with any myometrial invasion. Except in stage IA, grade 1 tumors, the chance of recommending further therapy in women with all stages and grades was significantly less if a complete staging procedure, including lymph node dissection, had been performed. Naumann et al conclude that complete surgical staging appears to decrease the chance that postoperative therapy will be recommended. They further recommend that future studies in women with endometrial cancer that do not require lymph node sampling should evaluate the frequency of adjuvant therapy in the absence of complete staging.

Comment by David M. Gershenson, MD

For the past several decades, adjuvant radiation therapy has been used extensively in patients with endometrial cancer. Historically, radiation was delivered in a variety of schedules—preoperatively, postoperatively, or both, and with a variety of methods—external-beam, brachytherapy, or combinations thereof. Unfortunately, practice patterns were not evidence-based. With the advent of comprehensive surgical staging and revision of the FIGO staging system in the 1980s, preoperative radiation in any form was deleted quickly from our armamentarium. The overarching principle was individualization of the use of radiation based on surgicopathologic findings. Clinical investigators are now focusing on the use of postoperative radiation, as reflected by the results of this survey report. Although not yet published yet, the results of GOG Protocol #99 have been presented in a national forum. In that study, patients with surgical stages IB-IIB (occult) were randomized to pelvic radiation vs. observation. Although the patients in the radiation arm had a significantly lower rate of vaginal recurrence (1.7% vs 12%), there was no difference in overall survival between the two groups. In addition, there is mounting evidence that patients who have negative retroperitoneal lymph nodes on extended surgical staging do not require any external pelvic radiation, regardless of the presence of unfavorable pathological factors—high-grade, deep myometrial invasion, vascular invasion—in the endometrial tumor. Of course, most experts would still recommend postoperative pelvic radiation for those patients with positive pelvic nodes or extended field radiation for those patients with positive paraaortic nodes (concomitant chemotherapy would also be recommended by several experts). In summary, the story of the implications of surgical staging for endometrial cancer is still unfolding. Future prospective, randomized trials will hopefully address some of these second-generation questions.

The least important prognostic factor in patients with endometrial cancer is:

a. myometrial invasion.

b. uterine size.

c. histologic grade.

d. histologic type.

e. lymph node status.