Taxane-based chemotherapy in senior adults with metastatic castration-resistant prostate cancer (mCRPC): A prospective international registry

Background: Docetaxel every 3 weeks is the standard of care in mCRPC. Efficacy and toxicity of taxanes in older men (70+) is poorly documented. Their enrolment in randomized trials is limited by exclusion criteria. This prospective international registry evaluates taxane toxicity and efficacy in such men in real life. Methods: 333 men with mCRPC (median age 76) were evaluated. PS, grade 3-4 comorbidities (Cumulative Illness Scoring Rate-Geriatrics [CISR-G]), dependence (Activity Daily Living [ADL], Instrumental ADL [IADL]), nutritional status, primary therapy received and outcomes (overall survival (OS), progression-free survival (PFS), best clinical benefit [based on pain, analgesic consumption, PS], PSA response, toxicity) were collected. Follow-up under therapy was 6 months. Results: In all, 24.0% had PS 2, 13.5% grade 3-4 comorbidities, 21% were dependent in 1 IADL, 15.6% in 1 ADL and 12.8% had a weight loss 5% within the past 3 months. According to SIOG (International Society of Geriatric Oncology, BJU Int 2010; 106: 462-69) algorithm, 65.2% were fit, 13.5% vulnerable, 16.8% frail and 4.5% had terminal illness. Most patients (62.4%) had pain at enrolment. Primary therapy was a taxane in 58% (3-weekly, 84.4%; median, 5 months) and another therapy in 42%. Clinical characteristics of men treated by taxanes and other therapies were comparable. At 6 months, 91% were still alive with taxanes vs 81% with other therapies (HR [95% CI] 0.53 [0.30-0.93] p=0.027). Taxanes also significantly increased PFS (66% vs 50%, HR 0.55 [0.40-0.76], p<0.001), best clinical benefit (60% vs 36%, HR 2.05 [1.47-2.85], p<0.001) and PSA response 50% (52.5% vs 37.4%, p=0.018). Main grade 3-4 toxicities with taxanes were fatigue (17.1%), nausea/vomiting (14%), diarrhoea (8.8%), anaemia (7.8%), nail change (6.7%) and febrile neutropenia (2.6%). Conclusions: Taxanes appear the most effective first-line therapy in older men with mCRPC and show an acceptable and manageable toxicity. Further analyses will compare health status measured by SIOG algorithm to physician independent evaluation and identify the most pertinent geriatric predictors of health status.