Prevention and Management of Drug‑Induced Gynecomastia

Prophylactic Breast Irradiation for Anti‑androgen Therapy

Administer prophylactic breast irradiation (total dose 8–15 Gy delivered in 1–3 fractions) 1–2 weeks before starting anti‑androgen therapy in prostate cancer patients to prevent painful gynecomastia. 1
In men receiving long‑term bicalutamide monotherapy, a single‑fraction breast‑bud irradiation of 8–10 Gy effectively prevents the development of gynecomastia. 1

Switch men who are taking spironolactone to eplerenone to avoid anti‑androgenic side effects that can cause gynecomastia. 3
Gynecomastia occurs in approximately 10 % of men on spironolactone 25 mg/day and in up to 52 % of men on doses ≥150 mg/day. 3
Eplerenone does not possess anti‑androgenic activity and is therefore the preferred mineralocorticoid receptor antagonist for men. 4
If reducing spironolactone to ≤50 mg/day does not resolve gynecomastia, transition to eplerenone or amiloride is recommended. 5

No pharmacologic agent reliably reverses ADT‑related gynecomastia; prophylactic breast irradiation remains the primary preventive strategy. 6
The incidence of gynecomastia varies with the ADT modality, reaching up to 80 % when estrogen therapy is used. 6
Non‑hormonal drugs such as antidepressants or anticonvulsants may alleviate vasomotor symptoms associated with ADT but do not reduce breast tissue enlargement. 6

Tamoxifen should not be used in patients with estrogen‑sensitive conditions without thorough evaluation, because it exhibits mixed agonist/antagonist activity. 7