Histopathological characteristics of microfocal prostate cancer detected during systematic prostate biopsy

Abstract

Objective: To evaluate the prevalence of adverse pathological features and the percentage of multifocal and/or bilateral disease in a series of patients who underwent radical prostatectomy (RP) for unique, microfocal prostate cancer (miPCa) detected on prostate biopsy in the pre-active surveillance (AS) era.

Patients and methods: In this retrospective, multi-institutional study, we analysed the clinical records of 131 consecutive patients who underwent either retropubic or robot-assisted RP for miPCa at two referral centres from January 2000 to December 2011. miPCa was defined as a neoplastic lesion present in ≤10% of core with biopsy Gleason score not applicable or biopsy Gleason score 6.

Results: There were 17 (13%) pT3-4 prostate cancers and a single case (0.8%) of pN+ tumour. Moreover, 31 (24.1%) patients had a Gleason score of >6 in the RP specimen. Therefore, unfavourable pathological features (pT3-4/N+ and/or Gleason score >6) were present in 40 (30.5%) patients. The median (interquartile range) prostate-specific antigen (PSA) density was 0.11 (0.09-0.17) and 0.16 (0.11-0.24) ng/mL/mL in patients with favourable and unfavourable pathological characteristics, respectively (P = 0.003). The receiver operating characteristic curve had an area under the curve value of 0.67 (95% confidence interval 0.56-0.77) for PSA density to predict the risk of unfavourable pathological features.

Conclusion: Patients with miPCa who are candidates for an AS protocol should be adequately informed that in ≈30% of cases the cancer might be locally advanced and/or with a Gleason score of >6. Those unfavourable pathological characteristics could be predicted by the PSA density value. Further studies should investigate the role of a more extensive biopsy sampling to reduce the risk of under-staging and/or under-grading in patients with an initial diagnosis of miPCa.

Keywords: active surveillance; microfocal prostate cancer; prostate biopsy; prostate cancer.