Prognostic factors for breast cancer squamous cell carcinoma and nomogram development for prediction: population-based research

Background: To investigate the prognostic survival factors of breast squamous cell carcinoma (BSqCC) and develop a comprehensive nomogram for predicting the survival of breast cancer squamous cell carcinoma. Methods: Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database to identify patients diagnosed with BSqCC from 1973 to 2015. The data was obtained using SEER Stat 8.3.4 software, collated, and analyzed by Excel 2016 software and SPSS (v25.0). Kaplan-Meier curves were used for survival analysis. The variables obtained by univariate analysis were introduced into the Cox proportional hazard model for multivariate analysis. The risk factors affecting the prognosis of BSqCC were obtained. P<0.05 was considered statistically significant. The independent prognostic factors of BSqCC were integrated and used to construct nomograms. Results: A total of 739 patients with BSqCC was included. The median age of diagnosis was 66 years. In most cases, the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was negative. One-third of the cases underwent breast-conserving surgery, and more than half of the cases underwent mastectomy (unilateral or bilateral). The 1-year survival rate was 81.2%, the 3-year survival rate was 62.9%, the 5-year survival rate was 54.4%, and the 10-year survival rate was 41.4%. Age (chi(2) =71.050, P<0.001), marital status (chi(2) =37.560, P<0.001), tumor size (chi(2) =27.931, P<0.001), surgical procedure (chi(2) =74.185, P<0.001), the number of positive lymph nodes (chi(2) =38.542, P<0.001), and the primary site (chi(2) =59.217, P<0.001) were significantly correlated with patient survival time. Among them, marital status (HR: 0.502, 95% CI: 0.318-0.794), age (HR: 2.186, 95% CI: 1.234-3.875), surgical procedure (HR: 1.03, 95% CI: 1.01-1.051), tumor size (HR: 1.505, 95% CI: 1.083-2.091) and the number of positive lymph nodes (HR: 1.277, 95% CI: 1.087-1.499) were independent risk factors for the survival of BSqCC. Five independent prognostic factors were then integrated for the construction of nomograms. Conclusions: BSqCC was a malignant tumor with a low survival rate. Age of onset was typically at an older age; mostly middle-aged and seniors. Marital status, age, surgical procedure, tumor size, and several positive lymph nodes were independent predictors of patient survival. At the same time, we developed a prognostic nomogram with excellent discrimination for breast cancer squamous cell carcinoma; therefore, it could help clinicians make decisions on a personal basis.