Vanishing prostate cancer on radical prostatectomy (RP) in the PSA era: incidence and follow-up data from a cohort of 1,060 patients between 1998 and 2010

Evaluation of pT0 prostate cancer in patients undergoing radical prostatectomy

OBJECTIVE

To evaluate the incidence, predictors and oncological outcomes of pT0 prostate cancer (PCa).

METHODS

We conducted a retrospective analysis of 20 222 patients undergoing radical prostatectomy (RP) for PCa at the Mayo Clinic between 1987 and 2012. Disease recurrence was defined as follow-up PSA >0.4 ng/mL or biopsy-proven local recurrence. Systemic progression was defined as development of metastatic disease on imaging. Comparisons of baseline characteristics between pT0 and non-pT0 groups were carried out using chi-squared tests. Recurrence-free survival was estimated using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

A total of 62 patients (0.3%) had pT0 disease according to the RP specimen. In univariable analysis, pT0 disease was significantly associated with older age (P = 0.045), lower prostate-specific antigen (PSA; P = 0.002), lower clinical stage (P < 0.001), lower biopsy Gleason score (P = 0.042), and receipt of preoperative transurethral resection, hormonal and radiation therapies (all P < 0.001). In multivariable analysis, lower PSA levels, lower Gleason score, and receipt of preoperative treatment were independently associated with pT0 (all P < 0.05). Seven patients (11%) with pT0 PCa developed disease recurrence over a median follow-up of 10.9 years. All seven patients had preoperative treatment(s) and three had recurrence with a PSA doubling time of <9 months. Compared with non-pT0 disease, pT0 disease was associated with longer recurrence-free survival (P < 0.05). Only one (1.6%) patient with pT0 disease developed systemic progression.

CONCLUSIONS

pT0 stage PCa is a rare phenomenon and is associated with receipt of preoperative treatment and features of low-risk PCa. Although pT0 has a very favourable prognosis, some men, especially those who received preoperative treatment, experience a small but non-negligible risk of disease recurrence and systemic progression.

Trends in prostatic adenocarcinoma tumor volume by visual estimation in prostatectomy specimens

We retrospectively reviewed 1792 consecutive radical prostatectomies (RP) from 2003 to 2006 at a single institution to establish tumor volume reference values, to determine current trends in visually estimated prostate adenocarcinoma tumor volume, and to characterize cases with no residual cancer on RP. Tumor volumes were recorded and subsequently stratified as very low, 0-1%; low, 1.1-10%; intermediate, 10.1-20%; high, 20.1-50%; and very high, >50%, with incidences of 11.7%, 52.1%, 21.5%, 13.2%, and 1.5%, respectively. The incidence of very low volume tumors increased within the time period (p=0.04). Seminal vesicle involvement was detected in 5.0% of cases and lymph node metastasis occurred in 1.4%. Volume categories statistically correlated with seminal vesicle invasion (p=0) and lymph nodes metastases (p=0). Eleven cases of no residual cancer (0.6%) were identified with a non-statically significant increase during the study (p=0.07). The rising incidence of very low volume tumors should be considered by clinicians when discussing treatment options with patients. A discrete tumor volume should be provided for RP specimens as it may be an important prognostic factor.