Abstract P3-05-37: Influence of Clinical Heterogeneity on Pregnancy Associated Breast Cancer survival: Systematic Review with Metanalysis

Abstract Objective: Pregnancy-associated breast cancer (PABC) is defined as diagnosed during pregnancy or within one year of childbirth, in which current evidence associates with poor prognosis, without showing what clinical characteristics could impact in survival. We aim to explore the impact of heterogeneity in risks on death and disease relapse, suggesting clinical characteristics that might improve PABC clinical outcomes. Methods: Medline, Embase, Cochrane, Lilacs and congress abstracts published since 2000 were used as data sources. Two reviewers independently selected manuscripts and extracted data and a third reviewer solved discrepancies. The primary outcome was overall survival (death), and secondary outcome was disease-free survival (death or relapse). Summarized hazard ratios were recalculated based on reported data. All metaanalyses used a random-effects model and heterogeneity was reported using the I2 method. Results: A total of 7143 studies were identified and 30 studies were included for metaanalyses. PABC is associated with a 96% (HR=1.96, 95%CI 1.58;2.35) higher risk of death and an additional 82% (HR=1.82, 95%CI 1.45;2.20) risk of death or disease relapse in comparison to a population of non-PABC or nulliparous BC. Through sensitivity analyses, we identified that clinical outcomes was impacted, possibly due to Ki-67 levels, poorly differentiated tumors, and triple negative breast cancer (TNBC) frequency in the study. Conclusions: PABC is correlated with poorer prognosis, suggesting that besides early diagnosis, Ki-67 levels, poorly differentiated tumors and TNBC might be relevant sources of inconsistency. So, such clinical sources of heterogeneity should be better investigated regarding the potential to evaluate alternative therapeutic strategies. PABC deaths compared to non-PABC population, represented as hazard ratio PABC deaths or disease relapse compared to non-PABC population, represented as hazard ratio Citation Format: MARCELO ANTONINI, BARROS T. TAIS, JULIANA M. REAL, REGINALDO G. COELHO LOPES, ODAIR FERRARO, ANDRE MATTAR, LUCAS OKUMURA. Influence of Clinical Heterogeneity on Pregnancy Associated Breast Cancer survival: Systematic Review with Metanalysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-37.