Re: Screening for prostate cancer: a review of the evidence for the U.S. Preventive Services Task Force

The effect of the USPSTF PSA screening recommendation on prostate cancer incidence patterns in the USA

Guidelines regarding recommendations for PSA screening for early detection of prostate cancer are conflicting. In 2012, the United States Preventive Services Task Force (USPSTF) assigned a grade of D (recommending against screening) for men aged ≥75 years in 2008 and for men of all ages in 2012. Understanding temporal trends in rates of screening before and after the 2012 recommendation in terms of usage patterns in PSA screening, changes in prostate cancer incidence and biopsy patterns, and how the recommendation has influenced physician's and men's attitudes about PSA screening and subsequent ordering of other screening tests is essential within the scope of prostate cancer screening policy. Since the 2012 recommendation, rates of PSA screening decreased by 3-10% in all age groups and across most geographical regions of the USA. Rates of prostate biopsy and prostate cancer incidence have declined in unison, with a shift towards tumours being of higher grade and stage upon detection. Despite the recommendation, some physicians report ongoing willingness to screen appropriately selected men, and many men report intending to continue to ask for the PSA test from their physician. In the coming years, we expect to have an improved understanding of whether these decreased rates of screening will affect prostate cancer metastasis and mortality.

Management of low risk prostate cancer-active surveillance and focal therapy

Low-risk prostate cancer, defined as Gleason Score 6 or less with PSA <10 ng/ml, is diagnosed in about half of men undergoing screening. Approximately 30% of men diagnosed with low-risk disease harbour high-grade cancer that is unrepresented on the biopsy. Moreover, a small percentage of low-grade cancers have molecular alterations that result in progression to aggressive disease. Favourable-risk prostate cancer should be managed with close follow up. Active surveillance is appropriate for most patients with low-risk disease, and radical treatment should be reserved for cases in which higher-risk disease is identified. In turn, focal therapy aims to preserve tissue and function in men who have been diagnosed with localized disease, and should be offered to men with higher risk disease at baseline, as an alternative to whole-gland radiation or surgery, or when the patient transitions from low-risk to higher-risk disease. The two strategies should be viewed as complementary elements of care that can be applied in a risk-stratified manner. In this Review, we discuss the rationale and current status of active surveillance-which constitutes a standard of care in most evidence-based guidelines-and comment on whether and when focal therapy should complement it in those men wishing to continue a tissue-preserving strategy.

Active surveillance for low-risk prostate cancer

Active surveillance for localized prostate cancer entails initial expectant management rather than immediate therapy, with "curative-intent" treatment deferred until there is evidence that the patient is at increased risk for disease progression. This is a response to the clearly documented risks of over diagnosis and overtreatment of low-risk prostate cancer, which in most cases poses little or no threat to the patient. It is based upon the prolonged natural history of prostate cancer and is an attempt to balance the risks and side effects of overtreatment against the possibility of disease progression and a lost opportunity for cure. Low-risk prostate cancer is more accurately viewed as one of multiple risk factors for the presence of higher grade prostate cancer. Like atypical small acinar proliferation, (ASAP), it may be managed with close follow up but without radical intervention, unless there is clear evidence of more aggressive disease.