Magnetic resonance imaging in the detection of local prostate cancer recurrence in patients with various PSA levels: a retrospective study

INTRODUCTION: Prostate cancer (PCa) is one of the most common cancer diseases. Approximately 30% of patients undergoing radical prostatectomy develop biochemical recurrence within the first 2 years after completion of treatment. One of the leading and available methods for diagnosing local recurrence of prostate cancer is multiparametric magnetic resonance imaging (mpMRI). OBJECTIVE : To determine the effectiveness of mpMRI in detecting local recurrence of PCa in patients after radical prostatectomy (RP) with different levels of total prostate-specific antigen (tPSA). MATERIALS AND METHODS : mpMRI of the pelvis was performed in 118 patients with biochemical relapse of PCa. The criteria for inclusion of patients in the retrospective study were the absence of previous radiation and hormonal therapy. Patients with positive surgical margins were excluded from the study. 46 patients were at low risk of PCa progression, 38 patients were at intermediate risk, and 34 patients were at high risk. Median obPSA 1.72 ng/ml (range 0.22 to 22.19 ng/ml). Median biochemical relapse 11 months. Patients were divided into groups depending on the level of obPSA (I group 0.2–0.5 ng/ml; II group 0.5–1.0 ng/ml; III group 1.0–3.0 ng/ml; IV group more than 3.0 ng/ml). Interpretation of the results was carried out according to the unified reporting system for assessing local recurrence of prostate cancer in patients after RP and RT — prostate imaging recurrence reporting (PI-RR). The probability of local recurrence of prostate cancer depending on the level of obPSA was analyzed using a statistical logistic regression model. DISCUSSION : Early diagnosis of PCa recurrence includes the need to identify local or distant recurrence, determine its volume and precise localization. mpMRI is highly effective in patients with BCR after RP with a total PSA level of more than 1 ng/ml. With a lower PSA level, the percentage of local recurrence detection is lower, which may be due to the small size of the recurrent lesion. In patients with biochemical recurrence of PCa, when mpMRI data indicate a low or uncertain probability of recurrence (PI-RR 1, 2 and 3), PET/CT with 68Ga-PSMA is recommended to exclude distant and regional metastases, as well as as an additional diagnostic method for detecting local recurrence of PCa. CONCLUSION : mpMRI is a highly effective diagnostic method for biochemical recurrence of prostate cancer, which allows for a personalized approach to further treatment. A significant relationship was found between the level of total PSA and the probability of detecting local recurrence according to mpMRI data. Local recurrence of prostate cancer is most often detected at a PSA level above 1 ng/ml, with a sensitivity of 91.8% and a specificity of 88.9%. With a lower value of total PSA, sensitivity and specificity decrease. With a recurrence focus value of ≥7.8 mm, local recurrence is confirmed in 90.4% of patients with subsequent histological examination.