A case of male breast cancer in association with bicalutamide-induced gynaecomastia.

A 70-year-old Type 2 diabetic male patient was referred with a rapidly growing lump in the right breast. He had been on Bicalutamide (Casodex, AstraZeneca) 150mg monotherapy for about 12 months for Gleason 8 (3 þ 5) adenocarcinoma of the prostate gland and had developed breast tenderness and gynaecomastia 3 months after commencing treatment. Pre-treatment bone scan and serum alkaline phosphatase levels were normal. Though he had undergone a radical left nephrectomy 9 years earlier for renal cell carcinoma, his family history did not suggest a genetic predisposition to malignancies. He responded favorably to Bicalutamide as reflected in his serum prostatic specific antigen (PSA) levels, which dropped from 211 to 1.4 ng/ml after 6 months of treatment and remained normal after 18 months. When examined, there was a 2.5 cm hard lump medial to the right nipple and palpable mobile axillary lymph nodes. Cytology of a freehand fine needle aspirate was frankly malignant (C5) and core biopsies confirmed a poorly differentiated adenocarcinoma from both the breast lump and axillary node. Immunohistochemistry indicated a primary breast origin. A chest radiograph was normal. He underwent a modified radical mastectomy and axillary node clearance. Final histology showed a 3 cm poorly differentiated infiltrating ductal carcinoma, which was oestrogen receptor (ER) positive (Quick score 6). Two out of 13 axillary lymph nodes contained metastatic deposits (T2N1M0). Adjacent breast tissue demonstrated gynaecomastoid-type ductal epithelial hyperplasia. Bicalutamide therapy was stopped and he received adjuvant Tamoxifen, external beam radiotherapy to the chest wall and the LHRH analogue, Goserelin. Bicalutamide is a non-steroidal anti-androgen used as standard monotherapy in patients with localized prostate cancer and significantly reduces the risk of disease progression. Breast pain and gynaecomastia are the most common adverse events in about half the patients though this is usually mild to moderate in the majority. Prophylactic low-dose irradiation of the breasts has been reported as effective in reducing the incidence and severity of Bicalutamide induced gynaecomastia and breast pain and though not common practice at the time, has now been introduced in this Urology Unit. To our knowledge this is the second confirmed case of breast cancer in association with Bicalutamide-induced gynaecomastia (correspondence AstraZeneca). Male breast cancer is rare (less than 1% of breast cancers), occurs at a mean age of about 60 years (median 68 years) and the predominant histological type is infiltrating ductal carcinoma in more than 85%. More than 85% are ER-positive and prognosis is comparable to females when matched for age and stage. Management is based on similar principles as for female breast cancer. ARTICLE IN PRESS