Predicting the likelihood of recurrence of pregnancy-associated breast cancer: Nomogram based on analysis of the French cancer network: Cancer Associé à La Grossesse

Objective: Pregnancy associated breast cancer (PABC) are defined as breast cancer diagnosed during pregnancy and during the year following delivery. The prediction of poor prognosis events (PPE) such as recurrence is a major medical challenge of management for women with PABC. The aim of this study was to build a nomogram based on selected clinical and histological variables to predict recurrence. Study Design: This retrospective study included 96 patients with PABC from January 2002 to January 2018. A multivariate Cox analysis of selected risk factors was performed and a nomogram to predict recurrence was built. The nomogram was internally validated. Results: The overall recurrence rate was 22% (21/95) and the 3-years recurrence rate was 13% (12/95). Age at diagnosis, histological type, immuno-histological class, tumor stage (TNM), node stage (TNM) were associated with PPE in univariate analysis, and were included in the final Cox model to develop the nomogram. The predictive model had a concordance index of 0.83 (95% Confidence Interval (CI), 0.81-0.85) and 0.78 (95% CI, 0.76-0.80) before and after the 200 repetitions of bootstrap sample corrections, respectively, and showed a good calibration. Conclusion: Our results support the use of the present nomogram based on 5 clinical and pathological characteristics to predict PPE in PABC with a high concordance. External validation is required to recommend this nomogram in routine practice.