Diagnosis of local relapse after radical radiotherapy (RRTH) of prostate cancer by biochemical PSA kinetics and transrectal ultrasonography (TRUS) verified by prostate biopsy

14631 Background: Patients (pts) with the cancer of the prostate after radical radiotherapy (RRTH) are followed by clinical examination, periodical measurements of PSA level, bone scan, bone x-ray examinations, CT of abdomen and pelvis. The biochemical progression (according ASTRO Consensus Panel) is not always equal the clinical progression. The next step in all cases of rising PSA is to diagnose or to exclude the local progression, which has to be distinguished from systemic progression. Methods: Prospective evaluation of effectiveness of the biochemical indicators as predictors of local relapse after RRTH and probability of positive tru-cut biopsy outcome in case of positive TRUS result. 51 pts with prostatic adenocarcinoma after RRTH, who experienced biochemical (PSA) progression were included. All of them had a negative bone scan results, negative abdomen-pelvis CT scan or ultrasonography and no clinical evidence of distant metastases. All pts underwent a tru-cut biopsy guided by TRUS. Each of them were eligible to local salvage procedures. The TRUS-guided tru-cut biopsy were performed in all pts. Results: The median observation time (between RRTH and biopsy) was 34 mo (11–78). The median PSA level at the biopsy was 2.46 ng/ml (0,69–11,26). TRUS was positive in 20/51 pts. In 31 pts, there was no evidence of local progression in TRUS. TRUS specificity was 62.02% (95% CI 48.75–75.39%) and sensitivity 40.91% (95% CI 27.42%–54.40). The biopsy outcome was positive in 22/51 pts (43%). The biopsy was positive in 58% (25/26) in subgroup with PSA level lower than 2.46 ng/ml and 27% (7/25) in group with PSA upper to this value. There were no significant associations between positive biopsy outcome and PSA velocity. Conclusions: In pts with suspicion of local relapse we observed the low predictive value of PSA level at biopsy (area under ROC curve = 0.6113). There were no associations between positive biopsy outcome and PSADT (PSA doubling time) which could help in better selection for invasive procedure. No significant financial relationships to disclose.