The natural history of low risk prostate cancer — how little we yet know
Posted Sep 28 2008 1:49pm
O’Donnell and Parker have reviewed available data regarding the definition, incidence, pathological characteristics, and natural history of low risk, localized prostate cancer. This is a topic of considerable importance to decisions about the management of men with early stage, potentially low risk disease.
Low risk prostate cancer has typically been defined as clinical stage T1/T2a, biopsy Gleason score ≤ 6, PSA < 10 ng/mL. This risk classification has provided a useful system for reporting of outcomes and for the production of clinical guidelines. However, “low risk disease” remains a broad category with a range of pathological characteristics and clinical behaviour.
Some (perhaps many), but certainly not all, low risk prostate cancers are clinically insignificant, destined never to cause any harm. The challenge of managing low risk, localized prostate cancer is to distinguish patients with clinically significant cancers, who may benefit from treatment, from the patients with clinically insignificant cancers who need no intervention beyond careful monitoring.
The natural history of untreated, low-risk, localized prostate cancer has still not been well studied, partly because it is a relatively recently identified form of the disease (clinically almost unknown prior to the availability of the PSA test), and partly because in the 1990s it became standard practice for men with low risk disease to receive immediate treatment.
Data from watchful waiting studies in the pre-PSA era, modelling studies to take account of so-called “lead time bias” and overdiagnosis associated with PSA testing, and the early results of active surveillance all provide insights into the likely natural history of low risk disease. However, as the authors carefully note,
There remains a major unmet need for markers of individual prostate cancer behaviour within the low-risk category. Such markers could be used to distinguish those men with truly indolent disease, suitable for observation, from those with significant prostate cancer that stand to benefit from treatment.
O’Donnell and Parker have reviewed available data regarding the definition, incidence, pathological characteristics, and natural history of low risk, localized prostate cancer. This is a topic of considerable importance to decisions about the management of men with early stage, potentially low risk disease.
Low risk prostate cancer has typically been defined as clinical stage T1/T2a, biopsy Gleason score ≤ 6, PSA < 10 ng/mL. This risk classification has provided a useful system for reporting of outcomes and for the production of clinical guidelines. However, “low risk disease” remains a broad category with a range of pathological characteristics and clinical behaviour.
Some (perhaps many), but certainly not all, low risk prostate cancers are clinically insignificant, destined never to cause any harm. The challenge of managing low risk, localized prostate cancer is to distinguish patients with clinically significant cancers, who may benefit from treatment, from the patients with clinically insignificant cancers who need no intervention beyond careful monitoring.
The natural history of untreated, low-risk, localized prostate cancer has still not been well studied, partly because it is a relatively recently identified form of the disease (clinically almost unknown prior to the availability of the PSA test), and partly because in the 1990s it became standard practice for men with low risk disease to receive immediate treatment.
Data from watchful waiting studies in the pre-PSA era, modelling studies to take account of so-called “lead time bias” and overdiagnosis associated with PSA testing, and the early results of active surveillance all provide insights into the likely natural history of low risk disease. However, as the authors carefully note,
Filed under: Diagnosis, Management, Treatment