Predicting hematologic toxicity of lutetium-177 prostate-specific membrane antigen therapy in metastatic castration-resistant prostate cancer using pretreatment gallium-68 prostate-specific membrane antigen positron emission tomography imaging: preliminary data in Asian patients.

BACKGROUND

Lutetium-177 (Lu-177) prostate-specific membrane antigen (PSMA) therapy is an emerging treatment for metastatic castration-resistant prostate cancer (mCRPC), but there is limited evidence on whether imaging can predict treatment-related toxicity. This study investigated whether pretreatment PSMA PET imaging parameters could forecast toxicity and outcomes in Asian patients undergoing Lu-177 PSMA therapy.

PATIENTS AND

METHODS

In this retrospective analysis, men with mCRPC treated with Lu-177 PSMA-617 at Koo Foundation Sun Yat-Sen Cancer Center, Taipei, were reviewed. Baseline Ga-68 PSMA-11 PET imaging metrics - including standardized uptake values (SUV), total lesion PSMA (TLP), and total tumor volume (TTV) - were assessed. Treatment response was measured by prostate-specific antigen (PSA) decline, and adverse effects and survival were evaluated from clinical records.

RESULTS

Eighteen men (median age: 75, range: 55-91) received a median of 2 (range: 1-6) cycles of Lu-177 PSMA therapy, with a mean administered radioactivity of 7.0 GBq (range: 3.0-7.4 GBq) per cycle. Grade 3/4 hematologic toxicities occurred in six (33.3%) patients, with thrombocytopenia (27.8%) and anemia (22.2%) most common. Higher TLP and TTV were linked to increased toxicity and poorer survival, while higher SUV mean was associated with better PSA response.

CONCLUSION

Pretreatment PSMA PET imaging may help predict adverse effects in Asian mCRPC patients undergoing Lu-177 PSMA therapy. Larger, prospective studies are needed for confirmation.