Importance of PSA variation – an analysis of PLCO trial data
Reviewed by Gokul Vignesh Kanda Swamy

This study looks specifically at the group of patients in the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening trial (PLCO), to investigate variations in prostate specific antigen (PSA) level. They have specifically included only patients who have had two PSA tests performed in a period of < two years and with an initial result of the first test <4ng/mL. 31,286 patients were selected for the study out of 38,340 in the intervention arm. They have excluded patients with initial abnormal PSA (>4ng/ml), when delay between two PSA tests was > two years, and only one or no PSA recording. According to authors the strict criteria was adopted to reduce bias and reduce confounding factors. Any occurrence of prostate cancer in this group was taken into account and patients were grouped into two categories as Gleason <7 and ≥7. The results showed a statistically significant association of initial PSA to age, BMI and tobacco smoking but not to race. Higher PSA is seen with increasing age and lower PSA levels with increasing BMI and tobacco smoking. In comparing the two PSA levels, roughly 50% men had about 20% fluctuation, which is not related to delay between first and second PSA check, age, BMI or race statistically. Another quarter of men did not have any PSA variation. Initial PSA value, especially low values, are strongly associated with PSA variation. Overall, the median variation of PSA levels was 3.4% (interquartile range: 15% to 26%). The authors have adjusted for age and baseline PSA in calculating for prostate cancer risk to PSA variation. There is a linear increase in risk with increasing PSA level at the second test, with an odds ratio of 1.079 (95% CI, 1.058-1.101) for each percent increase in PSA level. The variation in PSA level was not associated with a higher Gleason score. Compared to men with a decrease or no change in PSA, men with variations of ≥50% had a 4.2, 2.0 and 2.5 times greater risk of being diagnosed with a lesion having a Gleason score of ≤5, ≥6 but below 8, and ≥8, respectively. They acknowledge their limitations which are pertaining to the selection criteria, contamination by prior PSA and a homogenous population.

Variation of prostate-specific antigen value in men and risk of high-grade prostate cancer: analysis of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial Study.
Boniol M, Autier P, Perrin P, Boyle P.
UROLOGY
2015;85(5):1117-22.