Abstract PO5-16-08: Breast cancer in men: 15 years of experience in an oncology reference center in northern Mexico

Abstract Background Breast cancer in men accounts for about 1% of all breast cancers. Classic risk factors include increasing age, a family history of cancer, and mutations in predisposing genes. The alteration of the estrogen-androgen ratio has been as involved in the genesis of this cancer due to its increased risk in conditions such as liver dysfunction, obesity, marijuana use, thyroid disease, Klinefelter’s syndrome, hormonal therapies, orchitis, cryptorchidism, and testicular damage. Purpose Hereby we aim to update the analysis of the published demographic, clinical and treatment-related characteristics of this disease in our center including the last 15 years, as well as newly identified relevant variables that will serve as the basis for awareness and screening programmes for our population. Methods We performed a retrospective observational analysis of the medical records of men diagnosed with breast cancer that were treated in “Centro Universitario Contra el Cáncer” between January 2007 and December 2022. A total of seventeen cases of male breast cancer were included in the analysis. The variables included are age at diagnosis, body mass index, comorbidities, cigarette and alcohol use, method of diagnosis, histological type/grade, clinical stage, estrogen, progesterone, and human epidermal growth factor receptor-2 (HER2) receptor status, and treatment received. We also looked at the dates of symptom onset, diagnosis, and treatment to determine the intervals between these events. SPSS v25 software was used for data analysis. The Shapiro-Wilk test was employed to determine the normality of the variables. Variables with a normal distribution were described with median and interquartile range for the 25th and 75th percentiles. Categorical variables were expressed as absolute numbers and percentages. Results Although we found some similarities between the characteristics of our population and those reported in the American and European series, there were many significant differences. Mean age at diagnosis was 62.9 (±11.7) years, 5.5 years earlier than the reported age of 68.4 years. In terms of risk factors, our population was twice as likely to report a family history of cancer as the American series (41% vs. 15-20%). Overweight and obesity together accounted for 76.5% followed by alcohol consumption in 70.6% and cigarette smoking in 47.1% of patients. Diabetes mellitus and systemic arterial hypertension were present in 70% of our population. These entities are known to alter the estrogen-androgen ratio. The initial symptom in 88.2% of patients was a retroareolar tumor. The mean time from symptom onset to cancer diagnosis was 14.4 months. Estrogen and/or progesterone receptor status was positive in 82.3%. HER2 overexpression was not found. 17.6% of the cancers were classified as triple negative in contrast to the 0.3% reported in other series. Regarding treatment, 88.3% underwent upfront surgery, of which 76% were modified radical mastectomies. Axillary node dissection was performed in 86.6% of the cases and sentinel node biopsy in the rest. Seventy-six percent of patients received chemotherapy and radiotherapy in the adjuvant setting. Tamoxifen was the most common drug of choice (87.5%) in the patients considered as candidates for hormonal therapy Conclusions This study updates the results previously reported from our center with additional information that enabled new important conclusions to be drawn about our population. These findings provide the basis for a better understanding of this disease, which is necessary to establish public policies and recommendations to reduce the negative impact of this type of cancer. Table. Demographic and Clinical Characteristics of the Patients Citation Format: Fernando Peña, Javier A. Martínez-Moyano, Francisco Alvarado-Villarreal, Carlos Salazar-Mejía, David Hernández-Barajas, Oscar Vidal-Gutiérrez. Breast cancer in men: 15 years of experience in an oncology reference center in northern Mexico abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-16-08.