Addition of external beam radiation therapy to adjuvant chemotherapy is associated with a survival benefit for patients with stage IIIC endometrioid carcinoma

Abstract

Objectives: Evaluate whether the addition of external beam radiation therapy (EBRT) to adjuvant chemotherapy with or without vaginal brachytherapy is associated with better survival for patients with lymph node positive (stage IIIC) endometrioid endometrial carcinoma. Methods: Patients diagnosed between 2010 and 2015 with apparent early stage (T1-2/M0) endometrioid endometrial adenocarcinoma, without a history of another tumor, who underwent hysterectomy with lymphadenectomy and had positive lymph nodes were identified in the National Cancer Database. Those who received adjuvant chemotherapy (defined as receipt of treatment within 6 months from surgery) and had at least one month of follow-up were selected for further analysis. Overall survival was compared between patients who did and did not receive EBRT within 6 months from surgery with the log-rank test. A Cox multivariate model was also constructed to control for confounders. Stratified analysis by burden of lymphatic disease was also performed. Results: A total of 3116 patients were identified; 1458 (46.8%) received chemotherapy without EBRT and 1658 (53.2%) received chemotherapy with EBRT. In the present cohort, 911 (29.2%) patients received vaginal brachytherapy; of them 354 (38.9%) patients received chemotherapy and vaginal brachytherapy, while 557 (61.1%) patients received chemotherapy, EBRT and vaginal brachytherapy. Patients who received EBRT were more likely to be <65 years (55% vs 45%, p=0.005). However, tumor grade, size, endocervical invasion, presence of lymph-vascular invasion, patient race and comorbidities were comparable between the two groups. Patients who received EBRT and chemotherapy (with or without brachytherapy) had better survival compared to those who had chemotherapy only (with or without vaginal brachytherapy), p=0.001; 5-year OS rates were 83.1% and 77.9% respectively. After controlling for patient age, race, presence of comorbidities, insurance status, tumor size, grade and endocervical invasion, and presence of lymph-vascular invasion the addition of EBRT was associated with a survival benefit (HR: 0.75, 95% CI: 0.62, 0.91). Following stratification by number of positive lymph nodes, a survival benefit for the EBRT group was seen for those with 1-2 (p=0.045), 3-4 (p=0.07) and ≥5 (p=0.033) positive LNs. Conclusions: For patients with endometrioid endometrial adenocarcinoma metastatic to the lymph nodes, addition of EBRT to adjuvant chemotherapy (with or without brachytherapy) may be associated with a survival benefit. Evaluate whether the addition of external beam radiation therapy (EBRT) to adjuvant chemotherapy with or without vaginal brachytherapy is associated with better survival for patients with lymph node positive (stage IIIC) endometrioid endometrial carcinoma. Patients diagnosed between 2010 and 2015 with apparent early stage (T1-2/M0) endometrioid endometrial adenocarcinoma, without a history of another tumor, who underwent hysterectomy with lymphadenectomy and had positive lymph nodes were identified in the National Cancer Database. Those who received adjuvant chemotherapy (defined as receipt of treatment within 6 months from surgery) and had at least one month of follow-up were selected for further analysis. Overall survival was compared between patients who did and did not receive EBRT within 6 months from surgery with the log-rank test. A Cox multivariate model was also constructed to control for confounders. Stratified analysis by burden of lymphatic disease was also performed. A total of 3116 patients were identified; 1458 (46.8%) received chemotherapy without EBRT and 1658 (53.2%) received chemotherapy with EBRT. In the present cohort, 911 (29.2%) patients received vaginal brachytherapy; of them 354 (38.9%) patients received chemotherapy and vaginal brachytherapy, while 557 (61.1%) patients received chemotherapy, EBRT and vaginal brachytherapy. Patients who received EBRT were more likely to be <65 years (55% vs 45%, p=0.005). However, tumor grade, size, endocervical invasion, presence of lymph-vascular invasion, patient race and comorbidities were comparable between the two groups. Patients who received EBRT and chemotherapy (with or without brachytherapy) had better survival compared to those who had chemotherapy only (with or without vaginal brachytherapy), p=0.001; 5-year OS rates were 83.1% and 77.9% respectively. After controlling for patient age, race, presence of comorbidities, insurance status, tumor size, grade and endocervical invasion, and presence of lymph-vascular invasion the addition of EBRT was associated with a survival benefit (HR: 0.75, 95% CI: 0.62, 0.91). Following stratification by number of positive lymph nodes, a survival benefit for the EBRT group was seen for those with 1-2 (p=0.045), 3-4 (p=0.07) and ≥5 (p=0.033) positive LNs. For patients with endometrioid endometrial adenocarcinoma metastatic to the lymph nodes, addition of EBRT to adjuvant chemotherapy (with or without brachytherapy) may be associated with a survival benefit.