Objective: Lutetium-177 (177Lu) prostate specific membrane antigen (PSMA) radionuclide therapy (RNT) is an effective and safe treatment option in patients with metastatic castration resistant prostate cancer (mCRPC). The first aim of this study was to determine RNT response rate. The second and main aim of this study is measure overall and progression-free survival (OS and PFS) and to determine the factors have effect on OS and PFS.
Material and methods: Patients with mCRPC had 177Lu PSMA RNT every 6-8 weeks. Therapy response of each cycle determined wit PSA after 6-8 weeks. Overall survival and PFS were measured, then effects of age, Gleason grade, local recurrence, extraabdominopelvic located lymph node metastasis, visceral metastasis, prostate specific antigen (PSA) changing after the first RNT, pretreatment PSA, hemoglobin (Hb), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) values on survivals were determined.
Results: Forty-five patients were treated with total of 164 cycles of RNT. Fifteen patients (33%) had PSA decline of ≥50%, 23 patients (51%) showed any PSA decline and 20 patients (44%) showed PSA increase of ≥25%. Median OS and PFS were 17,1 months and 7,4 months. Patients had any or ≥50% PSA response after the first cycle, lower initial ALP (<120U/L) had longer OS and PFS. Patients had normal Hb showed longer OS and patients had lower initial PSA (<51ng/mL) had longer PFS. Patients had PSA progression of ≥25% had shorter OS and PFS.
Conclusion: Prostate specific antigen response after the first cycle, lower initial ALP is related to longer OS and PFS. Normal pretreatment Hb is a predictor of longer OS and lower initial PSA is related to longer PFS. Prostate specific antigen progression after the first cycle causes shorter OS and PFS.