Extent of pelvic lymphadenectomy and use of adjuvant vaginal brachytherapy for early-stage endometrial cancer

Abstract

Objective: To examine trends of adjuvant radiotherapy choice and to examine associations between pelvic lymphadenectomy and radiotherapy choice for women with early-stage endometrial cancer.

Methods: The Surveillance, Epidemiology, and End Results Program was used to identify surgically treated stage I-II endometrial cancer between 1983 and 2012 (type 1 n=79,474, and type 2 n=25,020). Piecewise linear regression models were used to examine temporal trends of intracavitary brachytherapy (ICBT) and whole pelvic radiotherapy (WPRT) use, pelvic lymphadenectomy rate, and sampled node counts. Multivariable binary logistic regression models were used to identify independent predictors for ICBT use.

Results: There was a significant increase in ICBT use and decrease in WPRT use during the study period. ICBT use exceeded WPRT use in 2003 for type 1 stage IA, and in 2007 for type 1 stage IB and type 2 stage IA diseases. In addition, number of sampled pelvic nodes significantly increased over time in type 1-2 stage I-II diseases (mean, 7.0-12.7 in 1988 to 15.2-17.6 in 2012, all P<0.001). On multivariable analysis, extent of sampled pelvic nodes was significantly associated with ICBT use for type 1 cancer: adjusted-odds ratios for 1-10 and >10 nodes versus no lymphadenectomy in stage IA (1.38/2.40), IB (2.75/6.32), and II (1.36/2.91) diseases. Similar trends were observed for type 2 cancer: adjusted-odds ratios for stage IA (1.69/3.73), IB (2.25/5.65), and II (1.36/2.19) diseases.

Conclusion: Our results suggest that surgeons and radiation oncologists are evaluating the extent of pelvic lymphadenectomy when counseling women with early-stage endometrial cancer for adjuvant radiotherapy.

Keywords: Adjuvant radiotherapy; Early stage; Endometrial cancer; Intracavitary brachytherapy; Whole pelvic radiotherapy.

Fig. 1.

Selection schema. Abbreviations; EMCA, endometrial cancer; NOS, not otherwise specified; and LND, lymphadenectomy.

Fig. 2.

Temporal trends in treatment patterns for stage I-II endometrial cancer. Frequency of pelvic lymphadenectomy (LND, yellow line), intracavitary brachytherapy (ICBT, red line), and whole pelvic radiotherapy (WPRT, blue line) is shown for A) type I stage IA, B) type 1 stage IB, C) type I stage II, D) type II stage IA, E) type II stage IB, and F) type II stage II disease. Dots represent percent proportion with 95% confidence interval.

Fig. 3.

Trends in performance of pelvic lymphadenectomy for stage I-II endometrial cancer. Annual percent changes are: A) 1.7 (95%CI 1.4–1.9, P < 0.001), B) 5.2 between 1988 and 1999 (95%CI 3.3–7.1, P < 0.001) and 1.8 (95%CI 1.3–2.3, P < 0.001), C) 2.1 (95%CI 1.4–2.8, P < 0.001), D) 1.9 (95%CI 1.6–2.2, P < 0.001), E) 2.3 (95%CI 1.9–2.8, P < 0.001), and F) 1.9 (95%CI 1.1–2.7, P < 0.001). Bars represent mean and standard deviation. Abbreviation: CI, confidence interval.

Fig. 4.

Radiotherapy choice bases on extent of pelvic lymphadenectomy. Bars represent proportion and 95% confidence interval. Among women who received adjuvant radiotherapy, proportion of intracavitary brachytherapy (ICBT) and whole pelvic radiotherapy (WPRT) are shown based on sampled nodes for pelvic lymphadenectomy (LND): A) type I stage IA, B) type I stage IB, C) type I stage II, D) type II stage IA, E) type II stage IB, and F) type II stage II.