Prolonged benefit from palbociclib plus letrozole in heavily pretreated advanced male breast cancer: case report

Introduction: Breast cancer in men is less common than in women and treatment recommendations are often derived from clinical trials exclusively involving women. Data on efficacy of CDK 4/6 inhibitors, which are the mainstay of treatment for hormone receptor–positive/HER2-negative advanced breast cancer, are lacking in male patients. Case report: We present a clinical case of prolonged benefit from palbociclib in combination with letrozole and LHRH analogue in a man who had previously been treated with six lines of endocrine therapies and chemotherapy regimens but was still in excellent clinical condition. Conclusions: This clinical case demonstrates that male breast cancer stands out as an endocrine-sensitive disease, which could potentially benefit from CDK 4/6 inhibitors in combination with endocrine agents even in very heavily pretreated settings of disease, underscoring both the importance of an accurate selection of patients for later treatment lines, taking into account disease history and previous treatment responses, and the peculiarity of breast cancer in men, which deserves dedicated clinical trials to tailor future recommendations.