Aim: Clinical trials have demonstrated the efficacy of Abiraterone and Enzalutamide (AE) in both chemotherapy naïve (COUAA-302 and PREVAIL) and chemotherapy refractory (COU-AA301 and AFFIRM) hormone resistant prostate cancer (HRPC). We examined the factors influencing their use in relation to chemotherapy in a real world setting.
Methods: We retrospectively examined the treatment data of patients on A/E from the Mosaic cancer database from Jan 2014 to Aug 2016.
Results: Twenty four patients met the search criteria; median age 79 years (range 57-88). All patients had prostate adenocarcinoma, 12 patients had Gleason score of 9 (range 6-10). Bone metastases were present in 14/24 patients (58%); 9/24 patients (38%) had both bone and visceral metastases. Most patients were ECOG 2 (62.5%) before A/E. The median Charlson comorbidity score was 10 (range 7-13). Twelve patients (50%) were treated with A/E after Docetaxel; one patient developed seizures related to E and was changed to A. One patient (4%) received E before chemotherapy, another A followed by E due to intolerance, before chemotherapy. Eight patients (33%) did not receive any chemotherapy, only A/E. Reasons for A/E after Docetaxel were rapid PSA rise and radiological progression. In chemotherapy naïve patients, treatment factors for AE were patients’ anticipated risk of intolerance to Docetaxel, poor performance status, patient preference for A/E or rapid progression. The median duration of A/E use was 8 months and 4.5 months for chemotherapy naïve and chemotherapy resistant HRPC respectively.
Conclusions: Patients were elderly with low performance status and high risk comorbidities. Clinicians have a strong role in deciding the optimal use of A/E in this population.