Management of Male Patients With Occult Breast Cancer: Analysis of the National Cancer Database

Introduction: Occult breast cancer (OBC) consists of <0.1% of breast cancer cases in the United States. Male occult breast cancer (mOBC) has not been well-studied outside of case reports, and management is largely based on female OBC (fOBC) studies. We aim to examine the prevalence of mOBC among those in the National Cancer Database with breast cancer and describe treatment modalities received by mOBC compared to fOBC. Methods: The National Cancer Database was queried for patients with OBC from 2004 to 2018. Chi-Square test and Fisher's exact tests compared patient, clinical, and facility characteristics by sex. Treatment modalities [systemic therapy, radiation therapy, axillary lymph node dissection, modified radical mastectomy (MRM)] were compared. A subgroup analysis examined pathologic upstaging in patients who underwent MRM. Results: Of 23,374 male patients with breast cancer, 0.13% were identified to have mOBC [versus 0.09% in fOBC]. cN2/N3 disease was significantly more prevalent in the mOBC cohort (61.3%) than in the fOBC cohort (30.7%, P < 0.001). Receipt of axillary lymph node dissection or MRM was not significantly different by sex. Male OBC (mOBC) patients were less likely to receive trimodality treatment than fOBC patients. In patients who underwent MRM, more mOBC patients [75%] were pathologically upstaged as T+ after mastectomy than fOBC patients [30%, P < 0.001], questioning the adequacy of diagnostic workup for mOBC compared to fOBC. Conclusions: This review confirms mOBC as an extremely rare disease. Multimodal treatments have been highly utilized to optimize care in this patient population. Further investigation is warranted to examine the survival benefit of treatment regimens for mOBC.