Men with clinically localized prostate cancer are faced with a wide range of treatment options, and only Gleason grading is universally used as a histopathological prognostic factor for this disease. The significance of perineural invasion in diagnostic biopsies is controversial. Opinion about whether or not it should influence treatment decisions is currently almost equally divided. To address this, the authors performed a systematic review of studies that examine the association between perineural invasion and prostate cancer recurrence. MEDLINE, Embase, and the Web of Knowledge were searched from January 1990 to December 2005.Outcomes analyzed were the development of biochemical or clinical recurrence. Twenty-one articles on the association of perineural invasion in biopsies and prostate cancer recurrence after radical prostatectomy (n ¼ 10) or radiotherapy (n ¼ 11) were found but none on its significance in the context of watchful waiting. Structured data extraction was performed to allow comparisons between articlesand to identify sources of heterogeneity to explain discrepancies in results. The considerable variation in study design, execution, and reporting precluded metaanalysis and quantitative risk estimation, but the weight of evidence suggested that perineural invasion in biopsies was a significant prognostic indicator, particularly in specific patient groups defined by presenting serum prostate-specific antigen levels and biopsy Gleason scores. Immediate treatment rather than watchful waiting may be more appropriate for patients with localized prostatic cancer and perineural invasion. However, the data are limited, and well-designed studies that use predefined stringent protocols are required to provide robust estimates of risk to aid in treatment planning.

Clinically localized prostate cancer is associated with a wide variation in biologic behavior, and men with the less aggressive form of the disease may never develop symptoms. There has been a rise in prostate cancer incidence in countries in which the blood test for prostatic-specific antigen (PSA) is common, and concerns have been expressed that this may be because of the increased detection of indolent disease, subjecting these men to unnecessary treatment and associated side effects. For the current review, the authors conducted a systematic evaluation of the literature regarding the outcomes of men who were diagnosed on the basis of a small volume of cancer in prostatic biopsies. The results indicated that, despite differences in study design and reporting, a significant proportion of patients with microfocal cancer, regardless of how it was defined, had adverse pathologic findings and a significant risk of PSA recurrence after undergoing radical prostatectomy. Biochemical and clinical recurrences also were observed after radiotherapy or watchful waiting. The authors concluded that patients with microfocal carcinoma on biopsy should be advised that their disease is not necessarily ''insignificant'' and should be counseled accordingly. Cancer 2008; 112:971-81.