Understanding the pathological features of focality, grade and tumour volume of early-stage prostate cancer as a foundation for parenchyma-sparing prostate cancer therapies: active surveillance and focal targeted therapy

OBJECTIVE To better understand the biology and incidence of the cancer foci within the prostate through a comprehensive literature review and a review of our own data, to establish the current level of knowledge regarding the pathological foundation for active surveillance (AS) or focal therapy (FT). PATIENTS AND METHODS A systematic review of the literature was performed, searching PubMed (R) from January 1994 to July 2009. Electronic searches were limited to the English language using the keywords 'prostate cancer', 'histopathology', 'radical prostatectomy', 'pathological stage' and 'focal therapy'. The authors' own data were also analysed and are presented. RESULTS Recent data have shown a significant pathological stage migration towards earlier disease comprising unilateral pT2a/b prostate cancer (PCa). The cancer volume of the clinically significant tumour (index lesion) has been proposed as a driving force of PCa progression and therefore should be identified and treated at an early stage. In general, most satellite lesions do not appear to be life-threatening. Other pathological features, such as Gleason score, extraprostatic extension and the spatial distribution of PCa within the prostate, remain important selective criteria for AS or FT. CONCLUSION The present study reviews the current knowledge of cancer focality, aggression and tumour volume. Further research is needed to better understand the biologic behaviour of each of the tumour foci within a cancerous prostate, and to employ this information to selected patients for no therapy (AS), parenchyma-preserving approaches (FT) or whole gland radical therapy.