Characteristics and survival of secondary male breast cancer: SEER database analysis.
Journal of Clinical Oncology
Background: Male breast cancer (MBC) is rare accounting for less than 0.5% of all cancer diagnoses in men. We used the term secondary male breast cancer (sMBC) to refer to ipsilateral and contralateral recurrences in addition to new primary MBC. Given its low incidence, data regarding the risk of developing sMBC and its characteristics are scarce. Methods: Multiple Primary Standardized Incidence Ratios (MP-SIR) session was conducted from the SEER*Stat software. We included all patients diagnosed with stage I,II and III MBC between 1990 to 2015 from the Surveillance Epidemiology and End Results (SEER) 18 registry. The standardized incidence ratio (SIR) was calculated as an estimate of the risk of a second primary malignancy based on the incidence in the general population. Descriptive statistics and Kaplan-Meier analysis were performed using SPSS software. Results: Among all 2321 men diagnosed with a first primary MBC during the study period, 28 patients had a subsequent diagnosis of MBC. The risk of sMBC was significantly elevated with SIR of 33.12 (95% CI, 22.18 – 47.56). The median latency period between the initial and subsequent diagnoses was 5.9 years. 82.1% of the patients were White, 14.3% Black and 3.6% Asian/Pacific Islander. Majority of the cases constituting 85.7% of sMBC were diagnosed in the contralateral breast. 67.8% of the sMBC remained hormone receptors status positive similar to the initial status of the primary diagnosis. 42.9% of the sMBC patients were diagnosed with stage I, 17.9% with stage II, 3.6% with stage III, 17.9% with stage IV and 17.9% of unknown stage. The median overall survival for sMBC was 96 months (95% CI, 11.3-180.6). We also found an increased risk of developing liver cancer (SIR: 2.16), prostate cancer (SIR: 1.29), thyroid cancer (SIR: 3.08) and acute myeloid leukemia (SIR: 2.4) in individuals after a diagnosis of MBC. Conclusions: Men diagnosed with breast cancer are at increased risk of sMBC in addition to other malignancies which require careful monitoring after completing initial treatment. Contralateral mammogram screening or prophylactic contralateral mastectomy can be considered based on patient’s preferences and values.
Khoury, J. , Yadav, S. , Rangarajan, T. & Zakalik, D. (2020). Journal of Clinical Oncology, 38 (15), e13690. doi: 10.1200/JCO.2020.38.15_suppl.e13690.