Age dependence of modern clinical risk groups for localized prostate cancer-A population-based study

Abstract

Background: Optimal prostate cancer (PCa) screening strategies will focus on men likely to have potentially lethal disease. Age-specific incidence rates (ASIRs) by modern clinical risk groups could inform risk stratification efforts for screening.

Methods: This cross-sectional population study identified all men diagnosed with PCa in Norway from 2014 to 2017 (n = 20,356). Age, Gleason score (primary plus secondary), and clinical stage were extracted. Patients were assigned to clinical risk groups: low, favorable intermediate, unfavorable intermediate, high, regional, and metastatic. Chi-square tests analyzed the independence of Gleason scores and modern PCa risk groups with age. ASIRs for each risk group were calculated as the product of Norwegian ASIRs for all PCa and the proportions observed for each risk category.

Results: Older age was significantly associated with a higher Gleason score and more advanced disease. The percentages of men with Gleason 8 to 10 disease among men aged 55 to 59, 65 to 69, 75 to 79, and 85 to 89 years were 16.5%, 23.4%, 37.2%, and 59.9%, respectively (P < .001); the percentages of men in the same age groups with at least high-risk disease were 29.3%, 39.1%, 60.4%, and 90.6%, respectively (P < .001). The maximum ASIRs (per 100,000 men) for low-risk, favorable intermediate-risk, unfavorable intermediate-risk, high-risk, regional, and metastatic disease were 157.1 for those aged 65 to 69 years, 183.8 for those aged 65 to 69 years, 194.8 for those aged 70 to 74 years, 408.3 for those aged 75 to 79 years, 159.7 for those aged ≥85 years, and 314.0 for those aged ≥85 years, respectively. At the ages of 75 to 79 years, the ASIR of high-risk disease was approximately 6 times greater than the ASIR at 55 to 59 years.

Conclusions: The risk of clinically significant localized PCa increases with age. Healthy older men may benefit from screening.

Keywords: Gleason score; age; age-specific incidence; diagnosis; prostate cancer; risk stratification.

Conflict of interest statement

Conflicts of Interest: TMS reports grant funding from Varian Medical Systems, unrelated to the present study, and honoraria from WebMD, Inc. and HealthLytix, Inc., unrelated to this work. OAA reports speakers’ honorarium from Lundbeck and is consultant for HealthLytix, Inc.

OAA has a patent application (US 20150356243) pending; AMD also applied for this patent application and assigned it to UC San Diego. AMD has stock options in Human Longevity, Inc, and is a founder and equity holder in CorTechs Labs, Inc., and HealthLytix, Inc. AMD reports research funding from General Electric Healthcare, unrelated to the present study. The other authors have no disclosures to report.

© 2020 American Cancer Society.

Figures

Figure 1.

Stratification of prostate cancer patients in Norway by Gleason scores and age, 2014–2017. Patients with Gleason 7 disease were divided into Gleason 3+4 (grade group 2) and Gleason 4+3 (grade group 3). Total number of patients with Gleason score data available: n=18,665 (91.7% of all prostate cancer cases in Norway).

Figure 2.

Proportion of men with Gleason 6 (Panel A, n=2,947), Gleason 7 (3+4; Panel B, n=3,946), and Gleason 6 or 7 (3+4) prostate cancer (panel C, n=6,893) who meet one or more of the following criteria: PSA ≥10 ng/mL, clinical T3–4 stage, or N1/M1 disease, by age group.

Figure 3.

Clinical risk group stratification of prostate cancer patients in Norway, 2014–2017. Total number of patients with risk stratification data available: n=14,303 (70.3% of all prostate cancer cases in Norway).

Figure 4.

Norway prostate cancer age-specific incidence rates (per 100,000 males) by clinical risk group stratification. Intermediate-risk prostate cancer is subdivided into favorable and unfavorable risk.