Background and objectives: To establish a prognostic stratification nomogram for T1-2 breast cancer with 1-3 positive lymph nodes to determine which patients can benefit from postmastectomy radiotherapy (PMRT).
Methods: A population-based study was conducted utilizing data collected from the Surveillance, Epidemiology, and End Results database. Chi-square test or Fisher exact test was used to compare the distribution of characteristics. Cox analysis identified significant prognostic factors for survival. A prognostic stratification model was constructed by R software. Propensity score matching was applied to balance characteristics between PMRT cohort and control cohort. Kaplan-Meier method was performed to evaluate the performance of stratification and the benefits of PMRT in the total population and three risk groups.
Results: The overall performance of the nomogram was good (3-year, 5-year, 10-year AUC were 0.75, 0.72 and 0.67, respectively). The nomogram was performed to excellently distinguish low-risk, moderate-risk, and high-risk groups with 10-year overall survival (OS) of 86.9%, 73.7%, and 62.7%, respectively (P<0.001). In the high-risk group, PMRT can significantly better OS with 10-year all-cause mortality reduced by 6.7% (P = 0.027). However, there was no significant survival difference between PMRT cohort and control cohort in low-risk (P=0.49) and moderate-risk groups (P = 0.35).
Conclusion: The current study developed the first prognostic stratification nomogram for T1-2 breast cancer with 1-3 positive axillary lymph nodes and found that patients in the high-risk group may be easier to benefit from PMRT.
Keywords: SEER; breast cancer; lymph nodes; nomogram; postmastectomy radiotherapy; prognosis.
Copyright © 2021 Hou, Zhang, Yang, Wu, Wang, Zhang, Yang, Hou, Wu, Wang, Dong, Guo, Shi and Ling.