Abstract
e12513 Background: Male breast cancer unlike female breast cancer is rare, representing approximately 1% of cancers that occur in men and approximately 1% of all BCs worldwide. It is managed by extrapolating from breast cancer in women due to it is rarity. We aimed to perform a large retrospective study with a focus on disease characteristics and overall survival. Methods: We performed a retrospective analysis of male breast cancer patients from the National Cancer Database (2004–2020). We obtained demographic, tumor, clinical and therapy data. Kaplan-Meier survival curves were created to estimate overall survival. Cox regression analysis was used to compare the groups within each variable. Results: We identified 31348 patients with primary diagnosis of male breast cancer (median age 66 years). Patients were predominantly white (82.1%) then black (13.4%). Most of patients are located in urban or metropolitan areas (95.9%) within a median of only 8.4 miles from the hospital where they received care. Almost equal patients treated at community hospitals (48.2%) and academic hospitals (50%). Patients were mainly covered by Medicare (49.0%) then Private insurance (40.8%). Most men who diagnosed with MBC had invasive cancer (88.3%). Only 1433 (4.6%) patients presented with metastases at diagnosis. The median tumor size was 3 cm. Most of tumors were moderately differentiated (36.1%) then (24.0%) poorly differentiated. In most patients, the tumor is present in the central portion of the breast. Several treatment modalities were used, of which primary surgical resection was the most common [90.7%). Among systemic therapies, hormonal therapy was the most common (57.1%%) then chemotherapy (34.3%) then radiation therapy (30.6%) and immunotherapy (4.8%). In terms of duration, time from diagnosis to surgery was 26 days (shortest), diagnosis to immunotherapy was 57 days, diagnosis to chemotherapy was 59 days, and time from diagnosis to radiation was 145 days (longest). The overall 30-day mortality was 0.3% (75/26333), the 90-day mortality was 0.9% (224/26333). Median overall survival is 67.1% (95% CI 143.371-150.349). Using cox proportional hazards model; factors influencing survival rate including Age, race, CDS P < 0.001, tumor size, year of diagnosis P < 0.000. All treatment modalities including surgery, chemotherapy and hormonal therapy was associated with increase overall survival with P < 0.001 (95% CI 1.245-1.370). Conclusions: This is the largest study to date on epidemiology and prognostic factors for MBC using NCDB. Old age, white race, greater comorbidity index, and larger tumor size are associated with decreased survival. Surgery and adjuvant therapy are associated with increased overall survival. Further studies warranted to elucidate the causes of improved survival associated with some of these factors will help improve quality of care for patients with MBC.