The Role of Adjuvant Therapy in Stage IA Serous and Clear Cell Uterine Cancer: A Pooled Analysis
Qu MX, Velker V, Leung E, Kwon J, Elshaikh MA, Kong I, Logie N, Mendez LC, Van Der Putten L, Donovan E, Munkarah AR, Wiebe EM, Louie AV, and D'Souza DP. The role of adjuvant therapy in stage IA serous and clear cell uterine cancer: A pooled analysis. Radiother Oncol 2017; 123:S292.
Purpose or Objective The optimal adjuvant management of Stage IA endometrial cancer with serous or clear cell histology is controversial. The objective of this study is to explore the role of adjuvant therapy in this population and identify patient characteristics of those suitable for observation. Material and Methods Retrospective chart reviews for consecutive patients who underwent hysterectomy for FIGO Stage IA endometrial cancer with serous or clear cell histology between 2004- 2015 were conducted in 6 academic centres. After excluding patients who were upstaged following surgery, a pooled analysis was performed for relevant endpoints. Results A total of 414 patients with a median age of 67 years(range 41-90) met the inclusion criteria. The most common histology were pure serous (64%,n=266) followed by mixed (27%,n=112) and pure clear cell (9%,n=36). Myometrial invasion was identified in 54%(n=222). Most patients underwent some surgical staging including sampling of pelvic lymph node (LN) (81%,n=335), para-aortic LN (45%,n=146), omentum (58%,n=239) and peritoneal washing (62%,n=219). Only 23% of patients (n=95) were considered to have adequate staging (pre-defined as ≥10 pelvic LN, sampled para-aortic LN and omentum). Thirtyfour percent of patients (n=140) received adjuvant chemotherapy and carboplatin/paclitaxel was most commonly used (77%, n=108). Adjuvant RT was delivered to 47%(n=178) of patients (external beam alone 16%,n=29; brachytherapy alone 56%, n=99; both 28%,n=50). The median follow-up was 2.7 years (range 0-12). Among patients who did not received any adjuvant treatment, 5- year actuarial estimates were as follows: local control(LC) 88%, regional control(RC) 93%, distant failure(DF) 15%, disease free survival(DFS) 74%, cancer specific survival(CSS) 91% and overall survival(OS) 82%. Adequate staging was associated with better CSS in patients who did not have adjuvant treatment (100% vs. 87%, logrank p=0.0035). Adjuvant RT was associated with better LC(5- year 96% vs. 84%, HR 0.32,logrank p=0.014). The 5-year RC was 93%, which was not found to be significantly improved by external beam RT. Adjuvant chemotherapy was associated with better LC(5-year 94% vs. 84%,HR 0.29, logrank p=0.0079), DFS(5-year 79% vs. 71%, HR 0.47, logrank p=0.033), but not for RC, DF or CSS. The delivery of at least 5 cycles of chemotherapy, was associated with a trend towards better LC (4-year 98% vs. 88%, HR 0.18,logrank p=0.090). Myometrial invasion, lymphovascular invasion, histological subtypes and the proportion of type II component were not found to be significant prognostic factors for LC, RR, DF or CSS. Conclusion Adjuvant radiotherapy and chemotherapy were associated with better LC and DFS but not for RC, DF or CSS for stage IA serous and clear cell uterine cancer. Observation may be an acceptable strategy in patients who have had adequate surgical staging.