Overall survival in patients with second primary breast cancer

Abstract

Objective: The objective of this study was to analyze the overall survival of patients with second primary synchronous and
metachronous breast cancer. Methodology: A retrospective cohort study on women with second primary breast cancer,
diagnosed between 2000 and 2015, was conducted. The cases were drawn from the Cancer Hospital registry and classified
according to the hospital registry rules for second primary cancers. The second primary breast tumor was defined as synchronous or metachronous according to the diagnosis of the second cancer: ≤6 months of the first tumor and >6 months
after the first tumor, respectively (Newman et al. 2001). 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 cases, 3.24% (375) had
second primary breast cancer, comprising 60.8% (228) synchronous and 39.2% (147) metachronous tumors. Regarding age,
patients were predominantly in the ≥60 years age accounting for 39.9% (91) of synchronous and 48.3% (71) of metachronous cases, with a mean patient age of 55 years for synchronous and 59 years for metachronous tumors. Overall, 5-year
survival in women with synchronous breast cancer was 86.5% (95%CI 79.69–91.21) and with metachronous cancer was
82.1% (95%CI 73.71–88.10), while 10-year survival was 69% for both synchronous and metachronous. Conclusion: There
was no difference in overall survival of patients with second primary synchronous and metachronous at 5 and 10 years
after treatment. However, in this cohort, we were not able to investigate the genetics profile to identify the presence of
associated genetic syndromes, a factor that can modify our findings.