Adjuvant chemotherapy and radiation in the treatment of stage I leiomyosarcoma

Objectives: Leiomyosarcoma of the uterus (LMS) is an aggressive tumor with a high recurrence rate. For women with stage I disease, NCCN guidelines currently recommend observation after resection of gross intraabdominal disease. However, the role of adjuvant therapy after surgery remains controversial. We analyzed the utilization of adjuvant chemotherapy and radiation therapy for stage I LMS and explored the association between usage of adjuvant therapy and overall survival. Methods: Patients who had pathologically confirmed stage I LMS treated from 2004 - 2016 whose data were recorded in the National Cancer Database (NCDB) were identified. Multivariable regression models were fit to estimate predictors of use of either adjuvant radiation therapy or chemotherapy. To analyze the impact of chemotherapy on all-cause mortality, an inverse probability of treatment weighted (IPTW) propensity score method was used to account for measured confounders and adjust for the receipt of radiation therapy in the outcome model. The process was repeated to analyze the impact of radiation therapy on all-cause mortality by using an IPTW propensity score method to account for measured confounders and adjust for the receipt of adjuvant chemotherapy. Results: A total of 2,426 patients were included in the analysis. Overall the chemotherapy utilization rate was 41.7% and the radiation utilization rate was 9.8%. The usage of chemotherapy remained stable between 39% and 44% between 2010 to 2016 whereas the usage of radiation decreased from 17% in 2010 to 4% in 2016. Adjuvant chemotherapy was more commonly prescribed in younger patients, those with poorly differentiated tumors, and tumors larger than 10cm. Adjuvant radiation was less likely to be utilized for patients living in areas with median socioeconomic status in the highest quartile. Overall 5-year survival for the entire cohort was 57.9% (95% CI 55.1 - 60.6%). After propensity score weighting, patient receiving chemotherapy had a 20% increased risk of all-cause mortality (HR 1.20, 95% CI 1.01 - 1.41, Figure 1A) with a 5-year survival of 53.8% (95% CI 49.4 -58.0%). After propensity score weighting and adjusting for receipt of chemotherapy, radiation therapy was not associated with mortality (HR 0.91, 95% CI 0.68 - 1.21, Figure 1B) with a 5-year survival of 55.0% (95% CI 47.0 - 62.3%). Download : Download high-res image (102KB) Download : Download full-size image Conclusions: In women with stage I LMS, adjuvant chemotherapy is commonly used. There is no association between use of either chemotherapy or radiation and improved survival.