Focal therapy for prostate cancer: possibilities and limitations

Context: A significant proportion of patients diagnosed with prostate cancer have well-differentiated, low-volume tumors at minimal risk of impacting their quality of life or longevity. The selection of a treatment strategy, among the multitude of options, has enormous implications for individuals and health care systems.

Objective: Our aim was to review the rationale, patient selection criteria, diagnostic imaging, biopsy schemes, and treatment modalities available for the focal therapy of localized prostate cancer. We gave particular emphasis to the conceptual possibilities and limitations.

Evidence acquisition: A National Center for Biotechnology Information PubMed search (www.pubmed.gov) was performed from 1995 to 2009 using medical subject headings "focal therapy" or "ablative" and "prostate cancer." Additional articles were extracted based on recommendations from an expert panel of authors.

Evidence synthesis: Focal therapy of the prostate in patients with low-risk cancer characteristics is a proposed treatment approach in development that aims to eradicate all known foci of cancer while minimizing damage to adjacent structures necessary for the preservation of urinary, sexual, and bowel function. Conceptually, focal therapy has the potential to minimize treatment-related toxicity without compromising cancer-specific outcome. Limitations include the inability to stage or grade the cancer(s) accurately, suboptimal imaging capabilities, uncertainty regarding the natural history of untreated cancer foci, challenges with posttreatment monitoring, and the lack of quality-of-life data compared with alternative treatment strategies. Early clinical experiences with modest follow-up evaluating a variety of modalities are encouraging but hampered by study design limitations and small sample sizes.

Conclusions: Prostate focal therapy is a promising and emerging treatment strategy for men with a low risk of cancer progression or metastasis. Evaluation in formal prospective clinical trials is essential before this new strategy is accepted in clinical practice. Adequate trials must include appropriate end points, whether absence of cancer on biopsy or reduction in progression of cancer, along with assessments of safety and longitudinal alterations in quality of life.