Prostate Cancer: Screening

See 2018 AUA Guideline Notes on PSA Screening

See 2017 CUA Guideline Notes on PSA Screening

Screening

• WHO Definition of Screening: identification of unrecognized disease in an apparently healthy, asymptomatic population by means of tests, examinations or other procedures that can be applied rapidly and easily to the target population
  • Screening refers to testing for disease in healthy, asymptomatic populations; whereas diagnosis is the identification of disease among individuals with signs or symptoms. The principal goal of screening is to improve overall health outcomes by identifying and treating disease at an earlier stage
• PSA testing increases detection rates of prostate cancer and leads to the detection of prostate cancers that are more likely to be organ-confined when compared with detection without the use of PSA.
• 7 RCTs to date on prostate cancer screening
  1. Stockholm
  2. Norrkoping
  3. Quebec
  4. PLCO
  5. ERSPC
  6. Goteborg
  7. CAP
• Among other design problems, the Stockholm trial screened with only one test and a high cut-off of PSA for biopsy; the Stockholm, Norrkoping and Quebec trials lacked allocation concealment; and the Quebec trial did not report according to intention to screen. As such, 3 (key as per CUA/AUA) randomized trials on prostate cancer screening:
  • Primary outcome is always cancer-specific mortality
  • PLCO (2008) – NO NET BENEFIT
    • Population: 76,685 US men aged 55-74 from 10 centers
    • Randomized to annual screening (PSA annually x 6 years, DRE annually x 4 years) vs. standard care
      • Biopsy recommended If PSA >4.0 or suspicious DRE
    • Primary outcome: cancer-specific mortality
    • Results:
      • No difference in PC mortality (Rate ratio (RR) 0.93 (95% CI 0.81–1.08) 17-year follow-up)
      • Increased incidence of prostate cancer in screening group (RR 1.05 (95% CI 1.01–1.09) 17-year follow-up)
      • No difference in disease stage
      • No difference in metastasis (RR 0.85 (95% CI 0.67 – 1.06))
      • Higher proportion Gleason 2-6 in screening arm; higher proportion Gleason ≥ 8 in control arm
        • Gleason 2–6: RR 1.17 (95% CI 1.11–1.23)
        • Gleason 7 disease RR 1.00
        • Gleason 8–10 disease RR 0.89 (95% CI 0.80–0.99)
    • Criticisms (4):
      1. High rates of contamination (77% as per 2018 AUA early detection prostate cancer guidelines)
      2. High rates of pre-screening
         • In control group at baseline, 34.3% had PSA test once within past 3 years, 9.8% had PSA tests two or more times within past 3 years; 31.9% had DRE once within past 3 years, 22.0% had DRE two or more times within past 3 years
         • After 1995, trial implemented exclusion criteria of more than one PSA test within last 3 years§
      3. Lack of adherence to diagnostic biopsies among patients with abnormal screening results in the screening arm
      4. Underpowered to detect mortality benefit
    • Andriole, Gerald L., et al. "Mortality results from a randomized prostate-cancer screening trial." New England Journal of Medicine 360.13 (2009): 1310-1319.
    • Pinsky, Paul F., et al. "Extended follow‐up for prostate cancer incidence and mortality among participants in the Prostate, Lung, Colorectal and Ovarian randomized cancer screening trial." BJU international 123.5 (2019): 854-860.
  • ERSPC (2009) (European Randomized Study of Screening for Prostate Cancer) – NET BENEFIT
    • Population: 162,243 men aged 55-69 (almost twice the size of PLCO) from 8 European countries; collection of trials conducted, some differences between individual trials
    • Randomized to screening every 4 years (PSA in most centres; some centres offered DRE) vs. standard care
    • Primary outcome: prostate cancer-specific mortality
    • Results (2019 results):
      • PC mortality: RR 0.80 (0.72–0.89)
        • Number needed to invite (NNI) to screening to prevent one prostate cancer death: 570
        • Number needed to diagnose (NND) to prevent one prostate cancer death: 18
        • Estimated that annual screening of men in the ERSPC aged 55 to 69 years would result in a 28% reduction in prostate cancer deaths (37% in those actually screened). The estimated number needed to screen to prevent one prostate cancer death was 98, and the number of cancers needed to be detected was 5
      • Incidence: RR 1.41 (1.36–1.45)
    • Lower rate (≈20-25%) of contamination
    • Schröder, Fritz H., et al."Screening and prostate-cancer mortality in a randomized European study." New England Journal of Medicine 360.13 (2009): 1320-1328.
    • Hugosson, Jonas, et al."A 16-yr Follow-up of the European Randomized study of Screening for Prostate Cancer." European urology 76.1 (2019): 43-51.
  • Goteburg (2010) – NET BENEFIT
    • Population: 20,000 men aged 50-64 from Sweden
      • Was included in ERSPC but was independently designed, initiated and reported separately from ERSPC. 60% of participants were included in ERSPC.
    • Randomized screening every 2 years (PSA) vs. control
      • Men with PSA at or above threshold (3.4 ng/ml between 1995 and 1998, 2.9 ng/ml between 1999 and 2004, and 2.5 ng/ml after 2004 (lower than others)) were invited for clinical follow-up with DRE, transrectal ultrasound and laterally directed sextant biopsies
      • Only 3% screening of controls; 93% complied with a biopsy recommendation
    • Results:
      • PC mortality: RR 0.65 (95% CI 0.49–0.87) 18-year follow-up
        • NNI: 231
        • NND: 10
      • Incidence: RR 1.51 (1.39–1.64)
      • 41% fewer advanced cases at diagnosis in the screening arm
    • Hugosson, Jonas, et al."Mortality results from the Göteborg randomised population-based prostate-cancer screening trial." The lancet oncology 11.8 (2010): 725-732.
    • Hugosson, Jonas, et al."Eighteen-year follow-up of the Göteborg Randomized Population-based Prostate Cancer Screening Trial: effect of sociodemographic variables on participation, prostate cancer incidence and mortality." Scandinavian journal of urology 52.1 (2018): 27-37.
  • There was contamination in the control arms for both ERSPC and Gotteburg trials but significantly lower than PLCO.
  • CAP (2018) (Cluster Randomized Trial of PSA Testing for Prostate Cancer) – NO NET BENEFIT
    • Population: 419,582 men aged 50-69 years from 573 primary care practices across the United Kingdom
    • Randomized to an invitation to attend a PSA testing clinic and receive a single PSA test vs standard (unscreened) practice
      • Men diagnosed with cancer were then offered inclusion in the ProtecT (Prostate Testing for Cancer and Treatment) trial, in which they were randomized to surveillance, surgery or radiation regardless of risk stratile.
    • Primary outcome: PC mortality
    • Results (median follow-up 10 years):
      • PC mortality: RR 0.93 (0.67 to 1.29)
      • Detection of low-risk prostate cancer cases increased
    • Criticisms:
      • High nonadherence rate with the intervention
      • Modest contamination in the controls
      • Inadequate follow-up to truly assess mortality
    • Martin, Richard M., et al. "Effect of a low-intensity PSA-based screening intervention on prostate cancer mortality: the CAP randomized clinical trial." Jama 319.9 (2018): 883-895.
• NNI for other common cancer screening tests
  • Colorectal cancer
    • FOBT: 900
    • Flexible sigmoidoscopy: 450
  • Breast Cancer
    • Mammography (2016 USPSTF recommendations: grade C age 40-49; grade B age 50-74)
      • Age 39-49: 1904
      • Age 50-59: 1339
      • Age 60-69: 377
• History of USPSTF Recommendations:
  • 1996
    • All men: grade I: current evidence is insufficient to assess the balance of benefits and harms
  • 2002
    • All men: grade I: current evidence is insufficient to assess the balance of benefits and harms
  • 2008
    • Men age <75: grade I:: current evidence is insufficient to assess the balance of benefits and harms
    • Men age ≥75: grade D: recommends against; there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits
  • 2012
    • All men: grade D: recommends against; there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits
  • 2018 (current)
    • Men aged 55-69: grade C: recommends selectively offering or providing the service to individual patients based on professional judgement and patient preferences; here is at least moderate certainty that the net benefit is small.
    • Men aged ≥70: grade D:recommends against; there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits

Questions

1. Describe the 3 key trials in prostate cancer screening?
2. List 3 limitations in interpreting the findings of the PLCO trial

Answers

1. Describe the 3 key trials in prostate cancer screening?
2. List 3 limitations in interpreting the findings of the PLCO trial

References

• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, chap 111