CT-guided Adjuvant Vaginal Brachytherapy for Endometrial Cancer: Efficacy and Sites of Failure with a Low-Dose Regimen

Abstract

The prognostic impact of number of dissected and metastatic lymph nodes, the lymph node metastasis ratio in stage IIIC endometrium cancer is not well-studied. Thus, the purpose of this retrospective multicentric study is to investigate the prognostic value of the number of dissected (LNC) and positive nodes (pN) with the value of the lymph node ratio (LNR) in FIGO stage IIIC endometrial cancer patient who received postoperative radiotherapy with or without chemotherapy. Materials/Methods: From January 2001 to December 2016, a total of 180 stage IIIC endometrial cancer patients who were treated with surgery and adjuvant postoperative radiotherapy (RT) (51 patients, 28%) or radiotherapy and chemotherapy (RT-CT) (129 patients, 72%) were retrospective analyzed. The LNR was defined as the number of positive lymph nodes divided by the total number of lymph nodes dissected. The endpoints were overall survival (OS) and progression-free survival (PFS). Results: The median age and follow up times for entire cohort were 60 years (range 36 e 88 years) and 50.5 months (range 2.8 e 199.2 months), respectively. The median dissected and metastatic lymph node numbers were 36 (range 5 e 34) and 2 (range 1 e 45), respectively. The receiveroperating characteristic (ROC) analysis identified 36 [AUCZ0.390 (% 95CI; 0.304-0.476); pZ002] as cutoff value for LNC, with 53% sensitivity and 53% specificity. For LNR, the cutoff value determined in ROC analysis was 10% [AUCZ0.636 (%95CI; 0.548 e 0.725), pZ0.001] with 60% sensitivity and 60% specificity. In univariate analysis, patients with an LNC 36 and LNR value less than 10% had better 5-year OS (68% vs 54% pZ0.04; %76.0% vs.45.0%, p < 0.001 respectively), 5-year PFS rates (67% vs 48% pZ0.01; 74% vs. 41%, p<0.001 respectively). Multivariate analysis only revealed that LNR was an independent prognostic factor for OS (hazard ratio [HRZ2.06 (95% CI; 1.26-3.36); pZ0.004) and PFS [HRZ1.83 (95%CI; 1.16-2.88; p Z 0.001)]. Additional analyses revealed grade I-II histology, receiving adjuvant chemotherapy showed better OS and PFS than counterpart groups (pZ0.02, p<0.001 and pZ0.04 and p<0.001 respectively). Conclusion: More than 10% LNR and high grade (grade III) histology are an important prognostic factors for OS and PFS in stage IIIC endometrial carcinoma patients. Our findings suggest that addition of chemotherapy to RT should be the preferred adjuvant treatment strategy for patients with stage IIIC endometrial cancer with higher grade disease and high lymph node metastasis ratio.