Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Focality in prostate cancer has been characterized in the literature with regards to its incidence at the time of prostatectomy, but conflicting reports defining the biological significance of unifocal lesions limits its clinical utility. Through the detailed histopathological characterization of 176 unifocal prostate cancers, this study revealed these tumours to demonstrate intermediate or high grade disease in half of patients, with adverse pathological features such as extraprostatic extension, seminal vesicle invasion, lymph node invasion, and large tumour volume in a third. This limits the ability of focality alone to identify patients who might be suitable candidates for lesion-ablative therapies. OBJECTIVE To characterize the anatomical distribution and pathological features of unifocal cancers, which have been reported to occur in 17-33% of men undergoing radical prostatectomy (RP), in whole- mount prostatectomy specimens. PATIENTS AND METHODS Between 1999 and 2008, a retrospective review of 1274 patients undergoing RP for clinically localized prostate cancer with pathological evaluation using whole-mount sectioning techniques and tumour mapping was performed from our prospective database. The study cohort comprised those patients who were found to have unifocal tumours. RESULTS A total of 176 (14%) patients fulfilled our criteria for having unifocal tumours. The median age at time of surgery was 61 years. The mean preoperative PSA level was 8.6 ng/mL. In all, 28% of patients were identified as having extracapsular extension (ECE) and 11% had seminal vesicle invasion (SVI). Of 98 patients undergoing pelvic lymph dissection, six (6%) had positive lymph nodes; 49% of tumours had Gleason score≤ yen;7 and 60% had Gleason pattern 4 or 5 found within the tumour. Mean tumour volume and maximum diameter were 3.3 mL and 1.7 cm, respectively. Overall, 89 (51%) tumours qualified as localized, organ-confined and low-grade cancers, possibly amenable to focal ablative approaches. The limitations of the present study include its descriptive and retrospective nature. CONCLUSIONS While unifocal prostate cancers were most commonly localized to the prostate, half of these patients were associated with intermediate- or high-grade disease. High-risk features including ECE, SVI, lymph node invasion (LNI), and large tumour volume were identified in a third of patients. Further studies assessing predictors beyond focality will be needed to determine whether patients can be identified before surgery who might be suitable candidates for lesion-ablative therapies.
- focal therapy
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