Comparative study of surgical orchidectomy and medical castration in treatment efficacy, adverse effects and cost based on a large prospective metastatic prostate cancer registry.

INTRODUCTION: Androgen deprivation therapy (ADT) remains the mainstay of treatment for metastatic prostate cancer (mPCa) but is associated with significant morbidities. Comparisons of medical castration (MC) and surgical orchidectomy (SO) have yielded varied results. We aimed to evaluate the oncological outcomes, adverse effect (AE) profiles and costs of MC and SO in patients with mPCa. METHODS AND MATERIALS: We reviewed 523 patients who presented with de novo mPCa from a prospectively maintained prostate cancer database over 15 years (2001-2015). All patients received ADT (either MC or SO) within 3 months of diagnosis. The data were analyzed with chi-square, binary and logistics regression models. RESULTS: One hundred and fifty one (28.9%) patients received SO while 372 (71.1%) patients had MC. The median age of presentation was 73 [67 -79] years old. The median prostate-specific antigen (PSA) was 280ng/ml [82.4-958]. Three hundred and thirty one patients (66.3%) had high volume bone metastasis and 57 patients (10.9%) had visceral metastasis. Clinical demographics and clinicopathological were similar across both groups. Similar oncological outcomes were observed in both groups. The proportion of PSA response (PSA <1ng/ml) was 65.6% for SO and 67.2% for MC (P = 0.212). Both therapies achieve >95% of effective androgen suppression (testosterone <50ng/dL). Time to castrate-resistance was similar (18 vs 16 months, P = 0.097), with comparative overall survival (42 vs. 38.5 months, P = 0.058) and prostate cancer mortality (80.1 vs. 75.9%, P = 0.328). Similarly, no difference was observed for the 4 AE profiles between SO and MC respectively; change in Haemoglobin (-0.75 vs. -1.0g/dL, P = 0.302), newly diagnosed Diabetes mellitus (4.6 vs. 2.9%, P = 0.281), control measured by HbA1c (0.2 vs. 0.25%, P = 0.769), coronary artery disease events (9.9 vs. 12.9%, P = 0.376) and skeletal-related fractures (9.3 vs. 7.3%, P = 0.476). After adjusting for varying governmental subsidies and inflation rates, the median cost of SO was $5275, compared to MC of $9185.80. CONCLUSION: Both SO and MC have similar oncological outcomes and AE profiles. However, SO remains a much more cost-effective form of ADT for the long-term treatment of mPCa patients.