Researchers have developed a nomogram that presents tailored estimates of overdiagnosis risk in PSA-detected prostate cancer (PCa). The information conveyed by the nomogram can be used to help clinicians and patients make treatment decisions.
“The chance that a prostate cancer detected by screening is overdiagnosed … can vary widely depending on the patient’s age and tumor characteristics,” Roman Gulati, MS, a statistical research associate for the Division of Public Health Sciences at the Fred Hutchinson Cancer Research Center in Seattle, and colleagues, wrote in Journal of the National Cancer Institute. “The purpose of this study is to use age, Gleason score, and [PSA] level to help inform patients with screen-detected prostate cancers about the chances their cancers were overdiagnosed.”
The team used a computer microsimulation model of prostate cancer natural history to generate virtual life histories in the presence and absence of PSA screening for a representative population of US men, aged 50-84 years from 1975-2005. Existing data on PSA levels, biopsy practices, and cancer diagnosis patterns was applied to learn about cancer progression in patients with and without screening.
Screening and biopsy patterns were then used to create a nomogram to predict individual chances of overdiagnosis based on the man’s age, Gleason score, and PSA level. The nomogram was fit to men who received a diagnosis of nonmetastatic prostate cancer through PSA screening (with PSA levels less than 10 ng/mL).
The prediction model estimated that the chances of overdiagnosis range from 2.9%-88.1%, depending on patient age, Gleason score, and PSA level at diagnosis. In their report, the investigators expressed their hope that the nomogram will provide useful information to patients and clinicians weighing the harms and benefits of various treatment options for screen-detected prostate cancers.