ASTRO 2022: Association of Prostate-Specific Antigen Screening Rates and Subsequent Metastatic Prostate Cancer Incidence in a National Healthcare System

(UroToday.com) The 2022 American Society for Radiation Oncology (ASTRO) Annual Meeting held in San Antonio, TX between October 23rd and 26th, 2022 was host to a session that addressed studies aimed at improving outcomes for high-risk prostate cancer patients. Dr. Alex Bryant presented results of his team’s work evaluating the association of PSA screening rates and subsequent metastatic prostate cancer incidence rates within the context of the Veterans Affairs Healthcare System.

 

There has been considerable controversy regarding the utility/cost efficacy of screening for prostate cancer with routine PSA testing. Two large studies in this space have evaluated the impact of routine PSA screening on long-term outcomes: ERSPC and PLCO. The ERSPC trial, a multicenter population-based randomized screening trial conducted across eight European countries, demonstrated a decreased hazard of overall mortality in patients undergoing routine screening after 16-year follow up (HR: 0.80, p<0.001).1 Conversely, the PLCO trial demonstrated no reduction in prostate cancer mortality after a median follow-up of almost 15 years, although there are significant limitations to this study, most notably of which is the considerable cross-over rate, with 86% of patients in the control arm having a PSA test done.2

 

In its 2012 iteration, the USPSTF had recommended against PSA-based screening (Grade D) for all men, with these guidelines since modified to a Grade C recommendation in men aged 55 to 69 years and continued as Grade D in those 70 years of age and older. This has had significant implications on screening rates, and thus potentially rates of prostate cancer diagnosis, metastasis, and mortality. As such, the authors posed the following question: Does natural variation in PSA screening predict metastatic prostate cancer incidence?

 

To address this, the author conducted a nationwide study of 128 Veterans Affairs (VA) facilities, which treated over 5 million veterans per year. The authors evaluated the following outcome: facility-level, 5-year lagged metastatic prostate cancer case count (2010 – 2019), with the following two exposures evaluated:

  1. Exposure 1: yearly facility-level PSA screening rate (2005 – 2014)
  2. Exposure 2: yearly facility level-long-term non-screening rate (2005-2014)

 

Looking at pre- versus post-2012 rates, the authors noted a temporal decrease in the rates of non-metastatic prostate cancer diagnoses, whereas the corresponding rates of metastatic prostate cancer increased, most significantly in the age 70+ year group (light blue below):

 

ASTRO 2022 Bryant_0 

 

Notably, facilities with lower PSA screening rates also had higher metastatic prostate cancer incidence as demonstrated below:

 

ASTRO 2022 Bryant_1 

 

 

On multivariable modeling controlling for patient racial composition, calendar year, proportion of patients aged 70 or older, use of MRI/PET, and hospital region, the authors demonstrated that facility-level PSA screening rates were associated with metastatic prostate cancer rates.

 

ASTRO 2022 Bryant_2 

 

In summary, the authors concluded that:

  1. PSA screening rates have declined
  2. Metastatic prostate cancer incidence rates have increased, particularly among patients ages 70 years or older
  3. VA facilities with lower PSA screening rates had higher subsequent metastatic prostate cancer incidence rates
  4. There appears to be sufficient epidemiological evidence supporting the efficacy of PSA screening in reducing the rates of metastatic prostate cancer

 

Presented By: Alex Bryant, MD, MS, Department of Radiation Oncology, University of Michigan, Ann Arbor, MI

Written by: Rashid Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2022 American Society of Radiation Oncology (ASTRO) Annual Hybrid Meeting, San Antonio, TX, Sat, Oct 22 – Wed, Oct 26, 2022.

References:
  1. Hugosson, J et al. A 16-yr Follow-up of the European Randomized study of Screening for Prostate Cancer. Eur Urol. 2019;76(1):43-51.
  2. Pinsky PF, et al. Extended mortality results for prostate cancer screening in the PLCO trial with median follow-up of 15 years. Cancer. 2017;123(4):592-599.

 

 

 

 

 

 

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