Metastatic Castration-Resistant Prostate Cancer: Two Case Reports of Dramatic Response with Abiraterone Acetate in Patients Heavily Pretreated with Chemotherapy
In 2000, a 49-year-old man presented with prostate adenocarcinoma with PSA at 6 ng/ml and Gleason score of 7 (3 + 4). He underwent a radical prostatectomy with pelvic lymph node ablation. After radical prostatectomy, the patient was staged pT2N0, but surgical margins were positive and intraprostatic lymphovascular invasion was diagnosed with no invasion of capsule or seminal vesicles. Gleason score was confirmed.\nIn September 2007, PSA monitoring showed an increase at 57 ng/ml. A CT showed enlarged iliac lymph nodes without metastases. Bicalutamide was started and PSA decreased to 1.2 ng/ml. In August 2008, upon increase in PSA, the patient began ADT (leuprolide 45 mg every 6 months). PSA dropped, but 1 year later, in August 2009, PSA was at 122 ng/ml and a CT showed retroperitoneal node enlargement. The patient began chemotherapy with docetaxel (75 mg/m2 every 3 weeks with prednisone 10 mg daily − 10 cycles). Partial node response was obtained and PSA dropped to 15 ng/ml after 10 cycles of docetaxel. In September 2010, progression was evident with bone and lung metastases and PSA at 666 ng/ml. Zoledronic acid was given and a second line of chemotherapy was proposed with cisplatin + VP16 (CDDP 75 mg/m2 and VP16 100 mg/m2 for C1, CDDP 67.5 mg/m2 and VP16 90 mg/m2 from C2/6 cycles). Stabilization was obtained until May 2011 when PSA rose to 1,069 ng/ml together with bone pain. PS was good at 0. A named-patient treatment with abiraterone was started at a dose of 1,000 mg/day together with prednisone 10 mg/day. After 1 month of abiraterone, PSA dropped to 143 ng/ml. Abiraterone was well tolerated. In December 2011, the patient remained in very good shape (PS 0, and PSA 14.8 ng/ml). A CT showed response of lung lesions (fig. ). Then, the disease remained stable until May 2012 with a bone scan indicating progressive bone metastases, while CT lung and node lesions remained stable. In August 2012, PSA was at 2,025 ng/ml and abiraterone was stopped. Chemotherapy was resumed with cabazitaxel (25 mg/m2 − 3 cycles). Tolerance was good and PSA dropped to 1,208 ng/ml after C2.