Efficacy and Feasibility of Cabazitaxel for Very Elderly Patients of ≥ 80 Years of Age With Metastatic Castration-Resistant Prostate Cancer: A Real-World Multi-Intuitional Analysis.

Background: Cabazitaxel (CBZ) is a key drug used for metastatic castration-resistant prostate cancer (mCRPC). However, clinical trial data on CBZ in very elderly patients are still lacking. This study aimed to investigate the efficacy and feasibility of CBZ for mCRPC patients of ≥ 80 years of age.

Methods: We retrospectively reviewed 484 patients with mCRPC who started CBZ treatment between September 2019 and March 2024. Therapeutic efficacy (PSA response, progression-free survival, overall survival, and safety profile) was compared between patients of < 80 years of age (< 80 group) and those of ≥ 80 years of age (≥ 80 group). In addition, risk factors associated with grade ≥ 3 neutropenia in the ≥ 80 group were investigated using a logistic regression model.

Results: Seventy-three (15.1%) patients were included in the ≥ 80 group. Although more patients in the ≥ 80 group received a reduced dose relative to the < 80 group, there was no significant difference in therapeutic efficacy between the two groups. The incidence of grade ≥ 3 neutropenia was similar between two groups (< 80: 27.5% vs. ≥ 80: 31.5%). In the ≥ 80 group, BMI < 22 kg/m² and neutrophil count ≤ 5000 cells/µL were significantly associated with grade ≥ 3 neutropenia, with odds ratios of 5.28 (p = 0.005) and 4.00 (p = 0.023), respectively.

Conclusion: In mCRPC patients of ≥ 80 years of age, CBZ showed similar safety and efficacy to younger patients. Our findings suggest that CBZ treatment with appropriate dose modification and prophylactic AE treatments may be still beneficial for elderly mCRPC patients in the current aging population.