Prostate-specific antigen doubling time among Japanese men in an annual health screening program.
BACKGROUND
Prostate-specific antigen doubling time (PSA-DT) has been studied as a parameter reflecting the biological doubling rate of clinically localized prostate cancer treated expectantly. With the use of PSA-DT, we studied the natural history of PSA changes among Japanese men in a health screening program.


METHODS
Between July 1994 and December 2002, a cohort of 1995 men aged 40-79 years underwent a total of 5700 PSA measurements in an annual multiphasic health screening program. Prostate-specific antigen doubling time was calculated using a log-linear regression model for 994 (49.8%) men who had three or more serial PSA measurements with a mean follow-up of 46.2 months.


RESULTS
Of the 994 men, 192 (19.3%) had a PSA-DT of less than 10 years and 12 (1.2%) had a PSA-DT of less than 2 years. Median PSA-DT in 14 men with a subsequent diagnosis of prostate cancer was 41.6 months (range, 12.2 to stable). A log-linear model statistically fitted 65 of 180 non-cancer patients with a PSA-DT of less than 10 years. The percentages of statistically fit cases increased with higher baseline PSA (5.3%, 7.7% and 8.7% among men with <1.0, 1.0-1.99 and 2.0-3.99 ng/mL, respectively) and older baseline age (3.7%, 8.5% and 6.9% among ages 40-49, 50-59 and 60 or older, respectively).


CONCLUSIONS
In a small but significant portion of men, PSA increases exponentially when it is still less than 4.0 ng/mL, with a PSA-DT of less than 10 years. The clinical significance of this finding should be evaluated by a prospective screening including biopsy.
Terai
Akito
A
Department of Urology, Kurashiki Central Hospital, Miwa 1-1-1, Kurashiki 710-8602, Japan. at7899@kchnet.or.jp
Matsui
Yoshiyuki
Y
Ichioka
Kentaro
K
Ohara
Hiroki
H
Terada
Naoki
N
Yoshimura
Koji
K
D000328:Adult; D000368:Aged; D006801:Humans; D007564:Japan; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis; D013997:Time Factors
D017430:Prostate-Specific Antigen