PSA outcome after metastasis directed therapy (MDT) of oligometastatic prostate cancer patients diagnosed by 68Ga-PSMA-PET/CT

Background Metastasis Directed Therapy MDT of oligometastatic prostate cancer OPCa is an emerging treatment option which may delay systemic therapy and its side effects Identifying OPCa patients suitable for local treatment by imaging modalities with a high sensitivity and specificity is crucial Therefore we analyzed PSA outcome after MDT of OPCa patients diagnosed by Ga PSMA PET CT retrospectively nbsp Methods Overall OPCa patients with le metastases in Ga PSMA PET CT treated with radiotherapy RT doses gt Gy EQD alpha beta were identified Biochemical progression free survival bPFS was calculated with Kaplan Meier method After stratifying patients by clinical and pathological parameters differences in bPFS were compared using log rank tests Cox regression analysis was performed to identify predictors of bPFS Toxicity was assessed using CTCAE V nbsp Results A total of metastases were treated Localizations were pelvic lymph nodes n and bones n of which were pelvic bones n ribs and sternal n vertebral body n On patient had a metastasis of the penis n The median follow up was months ndash with an overall survival of A treatment response was detected in patients The median PSA of ng ml ndash prior to MDT decreased significantly to ng ml ndash after treatment p lt For the entire cohort n median bPFS was months ndash Patients with solitary metastases had a significant longer bPFS with mean months ndash compared to months ndash for those with metastases p Furthermore patients without additional ADT and metastases in Ga PSMA PET CT had a significant higher risk for PSA progression after MDT HR CI ndash p Of patients had acute toxicity I deg and patient also experienced acute toxicity II deg Late toxicities I deg occurred in patient No acute or late toxicities gt II deg were observed nbsp Conclusion Using PSMA PET CT guided RT for MDT of OPCa led to a significant decrease in PSA levels with minimal therapy associated toxicity Especially patients with solitary metastases may benefit from this treatment approach However randomized trials with larger patient collectives are necessary