L. Hou (Nanchong, China)
Affiliated Hospital of North Sichuan Medical CollegeAuthor Of 1 Presentation
76P - The Clinical survival benefit of postmastectomy radiotherapy patients screened form T1-2N1M0 breast cancer according to tumor size and the number of lymph nodes
Abstract
Background
The prognostic value of postmastectomy radiotherapy (PMRT) in T1-2N1 breast cancer patients remains controversial. The aim of this study was to evaluate the benefit of PMRT in overall survival (OS) of T1-2N1 breast cancer patients based on the combination of lymph node numbers and tumor size.
Methods
We used data extracted from the Surveillance, Epidemiology, and End Results program. Women diagnosed as T1-2N1M0 breast cancet betweent 2004 and 2015 was abstracted. The primary outcome was overall survival. Multivariate Cox proportional hazard models were used to estimate the independent prognostic factors and to assess hazard ratios (HR) and their 95% confidence intervals (CI) with OS. Subgroup analysis of patients with different node positive number and tumor size were enrolled in our study.
Results
A total of 29366 patients included the final analysis, 20167 (68.7%) patients in no-PMRT group and 9199 (31.3%) patients in PMRT group. Multivariable Cox model analysis showed that radiotherapy could improve the overall survival (Hazard ratio [HR]0.89;95%CI 0.83-0.96, P=0.001) for T1-2N1 breast cancer patients. Subgroup analysis based on different tumor burden types showed that there was not all survival benefit to every subgroup. Analysis shows the benefits of PMRT are associated with exaltation in breast cancer overall survive rate among the patients with tumor size 4-5 cm and two or three positive lymph nodes respectively (HR 0.69; 95%CI 0.51-0.94; P=0.017or HR0.65; 95%CI 0.44-0.95; P= 0.027,separately). PMRT also has a beneficial effect for the patients with tumor size 2-3 cm and three positive lymph nodes (HR 0.61; 95%CI 0.48-0.78; P<0.001), but not in the others.
Conclusions
The integration of tumor size and the number of positive lymph nodes status seems to be a reliable predictor of overall survival from radiotherapy, which may enable physician to make clinical decision more precisely and effectually about PMRT, especially in the low -risk breast cancer subgroup.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.