Overall survival of patients with second primary breast cancer associated with molecular subtype and epidemiological profile at a cancer center

Abstract

Background The most prevalent cancer diagnosed in women in 2022 was breast cancer, with an estimated 2.26 million new cases worldwide. Among women with breast cancer, second primary breast carcinoma is the most common malignancy. The present study aimed to analyze the overall survival of second primary breast cancer patients at a cancer center. Methods A retrospective cohort study of women with second primary breast cancer, diagnosed between 2000 and 2015, was conducted. The cases were drawn from the Hospital Cancer Registry (HCR) and second primary breast cancer was classified according to the rules for these cancers. Survival curves were estimated using the Kaplan–Meier method. Results A total of 11.922 women with breast cancer were identified between 2000 and 2015. Of these, 3.24% (375) had second primary breast cancer, comprising 60.8% (228) synchronous and 39.2% (147) metachronous tumors. The 5-year survival rate was 86.5% (CI 79.69–91.21%) for women with synchronous breast cancer and 82.1% (CI 73.71–88.10%) for metachronous cancer cases. Both groups had a 10-year survival rate of 69%. Conclusion Overall survival of patients with second primary breast cancer was similar for both synchronous and metachronous tumors. Second primary tumors in this cohort appeared to occur sporadically, as patients were predominantly over 50 years of age with luminal B phenotype in the contralateral breast. Future studies should investigate the presence of associated genetic syndromes in these patients.