Does sentinel lymph node biopsy in endometrial cancer surgery have an impact on the rate of adjuvant post operative pelvic radiation? An Israeli Gynecologic Oncology Group Study

Objective: To compare the rates of post-operative radiotherapy between two methods of lymph nodes assessment during surgical staging for endometrial cancer (EC). Methods: We conducted a comparative study of all consecutive women with endometrial cancer who underwent sentinel lymph node detection and biopsy using blue dye and isotope scan (SLNB) at Kaplan Medical Center and patients from the IGOG database, who underwent staging lymphadenectomy (PLND). The primary outcome was the rate of adjuvant and therapeutic radiation. The secondary outcome was a comparison of disease-free survival (DFS) and overall survival (OS). Results: There were 138 patients in the SLNB group and 1022 women in the PLND group. The detection rate of SLN was 74% for unilateral detection and 54% for bilateral detection. In the PLND group 57% were high risk patients vs. 47% in SLNB group (p = 0.03). 43% of high-risk patients in the PLND group received adjuvant or therapeutic pelvic radiation vs. 28% of high-risk women in the SLNB arm (p = 0.017). No statistically significant difference in recurrence rates nor in death rates had been observed in the high-risk group patients. The 5-years survival in the high-risk PLND group was 80% and the recurrence rate was 19% vs. 75% 5-year survival and 14% recurrence in high-risk SLNB cohort, log-rank p = 0.82 for survival and long-rank p = 0.25 for recurrence. Conclusion: Endometrial cancer patients undergoing lymph node assessment by sentinel lymph node biopsy, receive less pelvic radiotherapy.