A 72-year-old man with metastatic prostate cancer (bone metastases, PSA 180 ng/mL) is initiated on androgen deprivation therapy. Which of the following adverse effects is NOT associated with long-term ADT in prostate cancer?

Explanation

## Adverse Effects of Androgen Deprivation Therapy (ADT) ### Overview **Key Point:** ADT (via GnRH agonists, antagonists, or bilateral orchiectomy) is the cornerstone of treatment for metastatic prostate cancer but carries significant metabolic and cardiovascular toxicity [cite:Harrison 21e Ch 182]. ### Adverse Effects Associated with ADT #### 1. Decreased Bone Mineral Density & Fracture Risk — ASSOCIATED **High-Yield:** Androgen deprivation causes rapid loss of bone mineral density (BMD), particularly in the hip and spine, leading to osteoporosis and increased fracture risk (hip, vertebral, wrist). - Mechanism: Androgens are anabolic; their loss triggers osteoclast activation and reduced osteoblast function. - Clinical impact: Fracture risk increases by ~20% per year of ADT. - Mitigation: DEXA scan baseline; calcium + vitamin D supplementation; bisphosphonates (zoledronic acid) or denosumab for high-risk patients [cite:Park 26e Ch 9]. #### 2. Gynecomastia & Breast Tenderness — ASSOCIATED **Clinical Pearl:** Gynecomastia occurs in 10–30% of men on ADT due to relative increase in estrogen/androgen ratio and increased aromatization of androgens to estrogens in peripheral tissues. - Mechanism: Loss of androgens → relative estrogen dominance → proliferation of breast tissue. - Management: Prophylactic tamoxifen (10 mg daily) or radiation therapy to breast tissue before ADT initiation can prevent gynecomastia. #### 3. Increased Cardiovascular Risk (MI, Stroke) — ASSOCIATED **Warning:** Multiple observational studies and meta-analyses demonstrate that ADT increases the risk of myocardial infarction, stroke, and cardiovascular death, particularly in men with pre-existing cardiac risk factors [cite:Robbins 10e Ch 20]. - Proposed mechanisms: Increased insulin resistance, dyslipidemia, weight gain, reduced HDL, increased inflammatory markers. - NCCN guidelines recommend baseline cardiovascular assessment and caution in men with unstable angina or recent MI. - Relative risk increase: ~1.2–1.4 fold over 5 years of ADT. #### 4. Improved Sexual Function & Libido — NOT ASSOCIATED **High-Yield:** This is the **opposite** of what occurs with ADT. ADT causes: - **Erectile dysfunction** in >80% of men. - **Loss of libido** (decreased sexual desire) due to suppression of testosterone. - **Decreased penile rigidity** and difficulty achieving/maintaining erections. - **Reduced ejaculatory volume** and orgasmic sensation. - These sexual side effects are among the most bothersome and contribute significantly to reduced quality of life. - Unlike hot flashes or gynecomastia, sexual dysfunction does **not** improve with time and may persist even after ADT cessation. ### Summary Table: ADT Adverse Effects | Adverse Effect | Incidence | Mechanism | Mitigation | |---|---|---|---| | Bone loss & fracture | ~20% increase/yr | Osteoclast activation | Bisphosphonates, denosumab, exercise | | Gynecomastia | 10–30% | Estrogen/androgen imbalance | Tamoxifen, breast radiation | | Cardiovascular (MI/stroke) | RR 1.2–1.4 | Metabolic syndrome, dyslipidemia | Baseline CV assessment, statins | | **Sexual dysfunction** | >80% | Testosterone suppression | Counselling, PDE-5i (limited benefit) | | Hot flashes | 50–80% | Hypothalamic dysregulation | Megestrol, SSRIs, venlafaxine | | Metabolic syndrome | 30–50% | Insulin resistance, weight gain | Diet, exercise, monitoring | **Answer: Improved sexual function and libido is NOT associated with ADT.**