Baseline prostate-specific antigen (PSA) levels among men aged 55 to 60 years was associated with long-term risk of clinically significant prostate cancer, according to a secondary analysis published in JAMA Network Open.
Researchers indicated that these findings suggest that repeated screening can be less frequent among men aged 55 to 60 years with a low baseline PSA level (i.e. <2.00 ng/mL), however men with higher baseline levels could benefit from more intensive strategies for screening.
“Our results support the modification of future screening practices based on baseline PSA level and could help to reduce the need for prostate biopsy and overdetection of clinically indolent [prostate cancer] without significantly compromising oncologic outcomes,” the authors wrote.
A screening group of 10,968 men aged 55 to 60 years from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening trial who had long-term follow-up was analyzed to determine the association of baseline PSA levels with long-term risk of any prostate cancer and of clinically significant prostate cancer.
Actuarial 13-year incidences of clinically significant prostate cancer diagnosis among participants with a baseline PSA of 0.49 ng/mL or less was 0.4% (95% CI, 0%-0.8%); 0.50-0.99 ng/ML, 1.5% (95% CI, 1.1%-1.9%); 1.00-1.99 ng/mL, 5.4% (95% CI, 4.4%-6.4%); 2.00-2.99 ng/mL, 10.6% (95% CI, 8.3%-12.9%); 3.00-3.99 ng/mL, 15.3% (95% CI, 11.4%-19.2%); and 4.00 ng/mL and greater, 29.5% (95% CI, 24.2%-34.8%) (all pairwise log-rank P ≤ 0.004). Only 15 prostate cancer-related deaths occurred during 13 years of follow-up, and 9 (60%) were among men with a baseline PSA level of 2.00 ng/mL or greater.
These data suggest that men younger than 60 years with PSA levels of 1.00 to 1.99 ng/mL can undergo less intensive screening than men with higher baseline PSA levels. Additionally, men with baseline PSA levels less than 1.00 ng/mL may even choose to discontinue screening. Given that 83% of men this study had baseline PSA levels less than 2.00 ng/mL, a significant number of men would be impacted by these changes. Contrastingly, men with baseline PSA levels of 2.00 or greater are likely to benefit from more intensive screening strategies.
“At a time when the concern regarding the overdiagnosis and overtreatment of indolent [prostate cancer] has led to intense scrutiny of the value of PSA levels as an effective screening tool, our data on the increasing risks associated with higher baseline PSA levels can be used to determine the optimal prostate cancer screening strategy for individual patients,” the authors wrote.
Notably, overall and clinically significant prostate cancer diagnosis rates were higher among men with PSA levels of 4.00 ng/mL or greater during the early portion of the study period, and diagnoses were delayed among men with PSA levels less than 2.00 ng/mL. Researchers indicated that this is likely due to immediate biopsy and diagnosis among patients with higher and more suspicious PSA levels at study enrollment, versus delayed biopsy and diagnosis among patients with low PSA levels at study entry whose PSA levels slowly increased to suspicious levels during the study.
According to the study, since the introduction of the widespread PSA screening in the early 1990s, diagnosis and radical treatment of prostate cancer has led to a 50% reduction in prostate cancer-specific mortality since peak rates. However, opinions on the utility screening have changed more recently, and there is now controversy over its use due to overdiagnosis and overtreatment of this cancer type.
Kovac E, Carlsson SV, Lilja H, et al. Association of Baseline Prostate-Specific Antigen Level With Long-term Diagnosis of Clinically Significant Prostate Cancer Among Patients Aged 55 to 60 Years. JAMA Network Open. doi:10.1001/jamanetworkopen.2019.19284.