Impact of tumor location on biochemical recurrence after laparoscopic radical prostatectomy.
The impact of zonal origin of the tumor on the prognosis after radical prostatectomy has been controversial. We investigated the influence of tumor location (anterior vs. posterior) on biochemical recurrence (BCR) after laparoscopic radical prostatectomy (LRP).
We reviewed 1082 patients undergoing LRP between 2005 and 2015, including 638 patients with pathological data on the index tumor location who did not receive neoadjuvant/adjuvant therapy. If there were several masses, we defined the largest lesion as the index tumor. BCR was defined as PSA >0.2 ng/mL. Between-group differences of the BCR rate were examined by Kaplan-Meier analysis and the Cox proportional hazards model.
The tumor was located anteriorly in 296 patients (43%) and was located posteriorly in 342 patients (57%). The anterior group was more likely to have a high initial PSA (≥10 ng/ml) than the posterior group (24.3% vs. 15.5%, p=0.005) and a larger tumor diameter (median: 1.6 cm vs. 1.3 cm, p=0.001), but had less pT3 disease (26.1% vs. 37.1%, p=0.003) and a lower pathological Gleason’s score (≤3+4 in 51.0% vs. 40.6%, p=0.011). During a median follow-up period of 5.0 years, 79 patients (12.4%) experienced BCR. The anterior group had a significantly lower BCR rate than the posterior group (p=0.008) (Figure 1). By multivariate analysis, posterior group was an independent predictor of BCR (hazard ratio (HR): 1.76, 95% confidential interval (95%CI): 1.09-2.86, p=0.021), as well as high initial PSA (≥10 ng/ml, HR: 2.36, 95%CI: 1.47-3.78, p=0.001), a higher pathological Gleason’s score (≥4+3, HR: 3.01, 95%CI: 1.70-5.36, p=0.001), and a positive surgical margin (HR:2.61, 95%CI: 1.44-4.76, p=0.002). Especially in patients with PSA ≥10ng/ml (n=125), pT3 (n=204), and Gleason’s score ≥4+3 (n= 348), there were larger differences of BCRs between the anterior and posterior groups (p=0.045, p=0.013 and p=0.131, respectively).
These results indicate that anterior index tumors are more likely to have favorable pathological characteristics despite a larger size. Anterior tumor location could be a new pathological factor associated with a lower BCR rate after LRP, especially in high-risk patients.