Rise in prostate-specific antigen in men with untreated low-grade prostate cancer is slower during spring-summer

Am J Ther. Sep-Oct 2006;13(5):394-9. doi: 10.1097/01.mjt.0000174346.36307.02.

Abstract

To test the hypothesis that the rate of rise in prostate-specific antigen (PSA) is slower during the spring-summer than during the rest of the year, we used PSA data from a prospective single-arm cohort study of men who had been followed to characterize a watchful observation protocol with selective delayed intervention for clinically localized, low-to-intermediate grade prostate adenocarcinoma. The rate of PSA increase was calculated as the visit-to-visit slope of log (PSA) against time, from 1 calendar-quarter visit to the next. The nonparametric Friedman test confirmed differences in rate of PSA rise among the calendar quarters (P = 0.041). Post hoc analysis showed the rate of PSA increase during Q2 was significantly slower than in each one of the other calendar quarters (Q1 versus Q2, P = 0.025; Q3 versus Q2, P = 0.002; Q4 versus Q2, P = 0.013), with no differences among quarters Q1, Q3, and Q4. These results are consistent with the vitamin D hypothesis that the higher 25-hydroxyvitamin D levels associated with spring and summer have a desirable effect on prostate biology. The therapeutic implication is that vitamin D supplementation in the range of 2000 IU/d, a dose comparable to the effect of summer, can benefit men monitored for rising PSA.

MeSH terms

  • Adenocarcinoma / blood*
  • Adenocarcinoma / surgery
  • Aged
  • Aged, 80 and over
  • Calcifediol / blood
  • Cohort Studies
  • Disease Progression
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Neoplasm Metastasis
  • Prospective Studies
  • Prostate-Specific Antigen / blood*
  • Prostatic Neoplasms / blood*
  • Prostatic Neoplasms / surgery
  • Seasons
  • Transurethral Resection of Prostate
  • Ultraviolet Rays
  • Ureteral Obstruction / complications
  • Vitamin D / physiology

Substances

  • Vitamin D
  • Prostate-Specific Antigen
  • Calcifediol