Combined androgen blockade therapy can convert RT-PCR detection of prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) transcripts from positive to negative in the peripheral blood of patients with clinically localized prostate cancer and increase biochemical failure-free survival after curative therapy

BACKGROUND: The clinical relevance of positive molecular staging as defined by reverse transcriptase-polymerase chain reaction (RT-PCR) detections of both prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) transcripts in the peripheral blood (PB) of patients with prostate cancer is still debatable. METHODS: We analyzed the biochemical failure-free survival (bFFS) of prostate cancer patients with positive molecular staging who underwent immediate curative therapy (Group I, n=39) compared to prostate cancer patients who did convert their positive molecular staging by the administration of combined androgen blockade (CAB) for 12 months prior to curative treatment (Group II, n=15). RESULTS: The median bFFS for Group I was 9 months (95% CI 5-13 months) and was significantly lower compared to Group II (>36 months, p<0.001). In Group I, the median time for PSA values of >2.0 ng/mL was 18 months (95% CI 12-21 months, range 12-36 months). Notably, only one patient from Group II reached PSA values>2.0 ng/mL at 36 months post-curative treatment. CONCLUSIONS: In patients with clinically localized prostate cancer and positive RT-PCR detection of PSA and PSMA transcripts in PB, CAB can convert positive molecular staging status to negative and by doing so it modifies the post-curative therapy bFFS of patients with clinically localized prostate cancer.