A review of additional primary cancers in breast cancer patients from a tumor registry of a large teaching hospital.

Abstract

e12529 Background: While advancements in healthcare access, screening, early detection, and treatment have enhanced survival rates and reduced mortality, breast cancer remains a major global health concern. Additionally, as survival outcomes improve for all cancers, the risk of developing second primary cancers has increased, creating new challenges for patients and healthcare systems. This study aims to quantify the prevalence and types of additional primary cancers in breast cancer patients, analyze differences in patient characteristics, and evaluate their impact on survival outcomes. Methods: This study utilized data from a large teaching hospital cancer registry to evaluate additional primary cancers in breast cancer patients over a 10-year period (2010–2019). Patients with a single primary cancer that also had a clinical or pathological stage IV disease were excluded. Statistical analyses, including chi-square, T-test, Wilcoxon, and Log-Rank tests, were conducted using SAS 9.4. Results: Among 2,721 breast cancer cases, 226 (8.31%) were found to have an additional primary cancer, comprising 154 (5.66%) cases of a second primary breast cancer and 72 (2.65%) cases of a primary cancer at another site. The most common non-breast primary cancers were gynecological (45.00%, n = 32), followed by colorectal (12.51%, n = 9), thyroid (9.72%, n = 7), and 5.51% (n = 4) each for lung, bladder, and kidney cancers. Family history of breast cancer was significantly higher in patients with a second primary (37.56%, p < 0.01) compared to those with a single primary (27.30%). Tobacco use was similar across both groups (30%). Patients with a second primary were older (p < 0.05) than those with a single breast primary [mean ± SD age: second primary breast, 66.5 ± 13 years; other primary sites, 67 ± 11 years; single primary, 61.7 ± 13 years]. Most single primary breast cancer cases (94.86%) were stage IIA or lower, with stage IA being the most common (33.33%). Among those with prior breast cancer, the median time to a second primary was 57.50 months (IQR = 49.00). Patients with a second primary had a significantly shorter mean survival 125 ± 4.1 months (mean ± SE, p < 0.01) compared to those with a single primary 135 ± 4.1 months (mean ± SE). Conclusions: Additional primary cancers are an influential concern in breast cancer patients, with second breast cancers, gynecological, colorectal, and thyroid cancers being the most common. Older age and a family history of breast cancer were key risk factors to developing an additional primary. Moreover, survival was significantly shorter in patients with second primaries compared to those with a single primary. These findings underscore the importance of long-term monitoring and tailored management strategies for breast cancer patients, particularly those at higher risk of developing additional primary cancers, to improve outcomes and survival.