Abstract PS11-31: Survival among female breast cancer patients who have survived a previous cancer

Abstract Background A growing number of women newly diagnosed with breast cancer have survived a previous cancer. Although little is known about their prognosis, this population is frequently excluded from clinical trials. Additional evidence about the survival of this population is needed, so that trial sponsors and investigators can create evidence-based trial eligibility criteria. Among women newly diagnosed with breast cancer, we examined the impact of previous cancer on overall and cancer-specific survival. Methods This population-based cohort study included patients age ≥66 years and diagnosed with breast cancer between 2005-2015 in linked SEER-Medicare data. Separately by breast cancer stage, we estimated overall survival using Cox regression and cause-specific survival using competing risk regression for women with and without previous cancer, adjusting for numerous covariates and competing risk of death from previous cancer, other causes, or the incident breast cancer. Results Of 138,576 women diagnosed with incident breast cancer, 10,822 (8%) had a previous cancer of another organ site. Many of these (n=5,014, 46.3%) were diagnosed ≤5 years of breast cancer. For all breast cancer stages except IV in which there was no significant survival difference, women with vs. without previous cancer had worse overall survival. This survival disadvantage was driven by deaths due to the previous cancer and other causes. In contrast, women with previous cancer generally had favorable breast-cancer specific survival; however this varied somewhat by stage and over time. Conclusions Many women newly diagnosed with breast cancer are already cancer survivors. These women had generally worse overall survival, worse survival from other causes, but their disease-specific survival varied depending on their breast cancer stage and over time. Citation Format: Sandi L Pruitt, Hong Zhu, Daniel Heitjan, David E Gerber, Bhumika Maddineni, Danyi Xiong, Ethan Halm, Caitlin Murphy. Survival among female breast cancer patients who have survived a previous cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-31.