Patterns of Practice for Adjuvant Treatment of FIGO 1B Grade 3 Endometrial Adenocarcinoma Following Publication of ASTRO 2014 Guidelines for Postoperative Treatment in Women With Early Stage High Risk Endometrial Cancer.

Purpose/Objective(s) In 2014, the American Society for Radiation Oncology (ASTRO) published evidence-based guidelines for the role of postoperative radiation therapy in endometrial cancer. These guidelines were also endorsed by the Society of Gynecologic Oncology (SGO). They strongly recommended that women with grade 3 endometrioid endometrial cancer with deep myometrial invasion) receive pelvic radiation (EBRT) and not vaginal cuff brachytherapy (VCBT) given their increased risk of pelvic recurrence based on high quality evidence. We analyzed patterns of practice before and after this consensus guideline was published. Materials/Methods We queried the National Cancer Database to identify all women with either FIGO 1C grade 3 disease from 2004-2009 and FIGO 1B grade 3 disease from 2009-2017 with endometrioid histology who were treated surgically. Patients were then stratified to treatment between 2004-2014 (prior to ASTRO guideline updates) and 2015-2017. Patients were excluded from final analysis if they were metastatic at diagnosis, received palliative-intent radiation, treatment parameters were unknown, or age Results We identified 6,792 patients with grade 3 endometrioid endometrial carcinoma meeting current FIGO 1B disease classification, diagnosed between 2004 and 2017. Adjuvant radiation was not delivered to 38% of patients identified in the study period, and 26% received both EBRT and VCBT. From 2004-2014, of the patients that received single modality adjuvant radiation, 1168 patients received VCBT only (56%) and 908 received EBRT only (44%). The corresponding numbers for 2015 to 2017 for VCBT and EBRT were 347 (62%) and 217 (38%), respectively. The increase in VCBT utilization in 2015-2017 was statistically significant (P = 0.025). Patients who received VCBT were more likely to receive chemotherapy, be treated at a community cancer center or academic cancer center, or live within 50 miles of the treatment center (all P Conclusion Based on ASTRO 2014 guidelines, EBRT is strongly recommended in patients with FIGO 1B/ grade 3 endometrioid endometrial carcinoma. However, the rate of EBRT paradoxically declined in the period after the publication of the guideline. This may be in part due to conflicting data from ongoing trials during that time such as GOG 249 and PORTEC 3. Further investigation is warranted to investigate reasons for these variations in practice. Author Disclosure C. Weil: None. F. Lew: None. D.K. Gaffney: Research Grant; NCI. Consultant; NCI. run meetings; NCI.G. Suneja: Research Grant; National Institutes of Health. Honoraria; National Comprehensive Cancer Network. Travel Expenses; National Comprehensive Cancer Network, Radiation Oncology Institute, American Board of Radiology; Radiation Oncology Institute, National Comprehensive Cancer Network, ASTRO.V.M. Williams: Involved in planning the mission and activities for the subcommittee; ARRO Equity and Inclusion Subcommittee.