The Role Of Biopsy Core Number In Selecting Prostate Cancer Patients For Active Surveillance

Main Category: Prostate / Prostate Cancer
Article Date: 01 Dec 2009 - 5:00 PST

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UroToday.com - Active surveillance (AS) entails a strategy by which selected men are managed expectantly with the intention of applying potentially curative treatment in case of signs of progression.

While AS strategy has changed the treatment and management of low-risk prostate cancers, it must also evolve as a diagnostic tool. Indeed, the proportion of patients treated due to upstaging or to prostate-specific antigen (PSA) rising during follow-up is substantial because of a lack of precise initial staging. In this context, the study of selection strategy for AS candidates is essential.

The criteria for AS varies greatly among different series and centres, with no strong, evidence-based data. These criteria depend on the biopsy-core number. The findings of our study clearly suggest that an extended biopsy strategy using 21 cores provides a better pathologic assessment for men with low-risk prostate cancer than a 12-core biopsy scheme and reduces the risk of misclassification of low-risk prostate cancer patients. The risk of having unfavourable disease defined by Gleason score >7 and/or pT3-4 cancer ranges from 28.6% to 35.9% relative to AS criteria when a 12-core strategy is used compared with 14.0-17.6% if the biopsy scheme is based on 21 cores.

The initial assessment of the misclassification risk is important for patient management and treatment decisions; however, it is surely not the best end point to address conclusion in men eligible for AS. The most important end point is cancer-specific survival rate. Nevertheless, as long as long-term oncologic outcomes are not available from patients managed with AS, the misclassification rate will represent a major study point of AS strategy analysis, and a necessary point of discussion between the urologist and his patient. The counterpart of extensive biopsy schemes is that such aggressive strategies have been hypothesized to increase the potential risk of overtreating patients whose tumours have a low impact on overall survival.

Is this statement (and the term overtreating) still correct in the AS era? Interestingly, the use of a 21-core biopsy scheme did not increase the overall number of men eligible for AS. The newly diagnosed cases in a 21-core strategy are compensated for by the men who are eligible for AS with the use of a 12-core scheme but reclassified among candidates for local therapy with the use of the 21-core protocol.

The use of the biopsy diagnostic tool can be improved. The next studies should better identify the subgroup of men who benefit most from extensive biopsy strategies. The prostate volume has to be considered. Another step will probably be to integrate urine prognostic markers, such as prostate cancer gene 3, to better characterize the potential aggressive behaviour of supposed low-risk prostate cancers. The actual importance of prostate biopsies has evolved from pure cancer detection to investigation of how biopsy results can assist clinical management for patients.

The inclusion of patients in AS protocols emphasizes the necessity of accurate staging strategies. Should all patients submitted to prostate biopsy be subjected to an extensive biopsy strategy? Only prospective studies comparing biopsy inclusion criteria and biopsy-core number for AS protocols and comparing AS with immediate radical treatment would be able to clarify the best candidates for AS according to outcome in terms of rising PSA and specific deaths. Clinicians, however, clearly have to deal with the biopsy-core number for treatment decisions and patient information.

Written by Guillaume Ploussard, MD and Alexandre de la Taille, MD as part of Beyond the Abstract on UroToday.com.

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