Studies reveal drop in PCa treatment, rise in metastatic disease

Findings from two new studies provide insight on how changing recommendations for prostate cancer screening and management have impacted practice patterns.

In what they believe to be the first population-level analysis of treatment rates during the period after the U.S. Preventive Services Task Force (USPSTF) issued recommendations discouraging PSA screening, Tudor Borza, MD, MS, and colleagues conducted a retrospective cohort study using Medicare data (Health Aff [Millwood] 2017; 36:108-15). Their review included 67,023 Medicare beneficiaries aged 66 years and older who were newly diagnosed with prostate cancer in 2007 to 2012.

They analyzed population-based treatment rates as a measure of trends in diagnosis and treatment patterns along with treatment rates among diagnosed men, which would be sensitive only to changes in treatment patterns. A third analysis investigated trends in treatment for the subgroup of men with a high risk of non-cancer mortality within 10 years of diagnosis.

The authors found the population-based treatment rate fell by 42% between 2007 and 2012 (from 4.3 to 2.5 per thousand Medicare beneficiaries) while there was only an 8% drop (from 718 to 659 per thousand Medicare beneficiaries) among diagnosed men.

“The difference between these two rates indicates that decreased screening for prostate cancer led to substantially fewer men being diagnosed and therefore eligible for treatment,” said Dr. Borza, of the University of Michigan, Ann Arbor.

“However, the modest decrease in treatment rate among diagnosed men indicates that use of surveillance strategies has only slightly increased. In our population, nearly three-fourths of men diagnosed with prostate cancer received initial curative treatment as opposed to active surveillance or watchful waiting,” added Dr. Borza, who worked on the study with Brent K. Hollenbeck, MD, MS, and colleagues.

There was no change in treatment rates for men with ≤10-year life expectancy related to comorbidities.

“These findings show that the adoption of less intense screening practices outpaced the adoption of surveillance strategies. Once a diagnosis of prostate cancer is established, it appears that patients and physicians are still cautious about choosing surveillance as the initial treatment. We need better tools to identify which men should be screened and, among those diagnosed, which men should be treated aggressively. It’s that uncertainty that leads to different approaches to treatment based on how different patients and physicians view the risk. If we get better at predicting who is at highest risk, we can more accurately tailor screening and treatment,” Dr. Borza said.

Next: Reversing stage migration

Reversing stage migration

Separately, in a study published online in JAMA Oncology (Dec. 29, 2016), Jim C. Hu, MD, MPH, and colleagues investigated trends in prostate cancer presentation for the years 2004 to 2013 using Surveillance, Epidemiology, and End Results data. They identified 545,399 men ages 40 years and older with a pathologically confirmed diagnosis of prostate cancer and extracted information on PSA, distant metastases, T stage, and Gleason grade.

Also see: How will the ProtecT study affect your care of PCa patients?

Stratifying the men into two groups by age, researchers found that in men <75 years of age, there were significant increases between the first and last years of the study period in the proportion presenting with distant metastasis (2.7% to 4.0%) and with intermediate- and high-grade disease (46.3% to 56.4%). Statistically significant and more dramatic increases were noted for both endpoints among men aged ≥75 years, with the proportion presenting with distant metastasis nearly doubling from 6.6% to 12.0% and the proportion with intermediate- and high-grade prostate cancer rising from 58.1% to 72%. An adjusted analysis found that among the older men, the incidence of distant metastasis decreased from 2004 to 2011 and rose thereafter.

“The introduction of PSA screening in the early 1990s was accompanied by a 70% reduction in the incidence of metastatic prostate cancer. In 2008, the USPSTF recommended against PSA screening in men aged 75 years and older and in 2012, the USPSTF expanded the recommendation to include all men, unconditionally. We demonstrate for the first time that the incidence of metastatic prostate cancer is increasing in men aged 75 years and older, following a nadir in 2011, in a nationally representative tumor registry,” said Dr. Hu, of the LeFrak Center for Robotic Surgery at Weill Cornell Medicine, New York Presbyterian Hospital, New York.

“Considering evidence that PSA screening rates have dropped significantly along with the use of prostate biopsy and radical prostatectomy, the increased incidence in this age group of metastatic prostate cancer, which is incurable, is concerning,” Dr. Hu said.

Dr. Hu said he hopes the findings of the study and earlier work demonstrating the previously unrecognized flaws of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial give the USPSTF cause for reconsidering the grade D recommendation that the harms of PSA screening outweigh the benefits.

“A PSA test requires only a blood draw and knowing the specific numerical result does no harm, in and of itself. The patient may then decide whether a repeat test is necessary based on a borderline value, and new technologies have been introduced in precision medicine and imaging to help risk stratify and aid decision-making for biopsy, and if positive whether active surveillance is appropriate,” he commented.

“Furthermore, the fact that approximately 50% of men diagnosed with prostate cancer are now opting for active surveillance weakens the argument that over-diagnosis of prostate cancer leads to overtreatment. I believe that men should have the right to choose whether to pursue PSA testing and that the unconditional recommendation against PSA testing is too drastic a measure.” Dr. Hu added that he does not believe in annual mass screenings.

“The acceptance of active surveillance for low-risk prostate cancer and for low-intermediate-risk cancers in men with <10-year life expectancy demonstrates that patients understand the generally indolent behavior of these cancers and that physicians are avoiding overtreatment. Similarly, I believe that U.S. men have gained medical knowledge to choose for themselves when and how often to do PSA testing and that they do not need a blanket statement to protect them from ‘overdiagnosis’ and ‘overtreatment,’ ” he said.

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