DIHYDROTESTOSTERONE AND TESTOSTERONE LEVELS IN MEN SCREENED FOR PROSTATE-CANCER - A STUDY OF A RANDOMIZED POPULATION

Objective To investigate the possible relationship between serum level s of prostate specific antigen (PSA), dihydrotestosterone (DHT), testo sterone, sexual-hormone binding globulin (SHBG) and tumour stage, grad e and ploidy in 65 cases of prostate cancer diagnosed in a screening s tudy compared to 130 controls from the same population. Patients, subj ects and methods From a population of 26 602 men between the ages of 5 5 and 70 years, 2400 were selected randomly and invited to undergo scr eening for prostate cancer using a digital rectal examination, transre ctal ultrasonography and PSA analysis. Among the 1782 attendees, 65 ca ses of prostate cancer were diagnosed. Each case was matched with two control subjects of similar age and prostate volume from the screening population. Frozen serum samples were analysed for PSA, DHT, testoste rone and SHBG, and compared to the diagnosis and tumour stage, grade a nd ploidy. Comparisons between these variables, and multivariate and r egression analyses were performed. Results There were significant diff erences in PSA level with all variables except tumour ploidy, DHT leve ls were slightly lower in patients with prostate cancer but the differ ence was not statistically significant. There was a trend towards lowe r DHT values in more advanced tumours and the difference for T-stages was close to statistical significance (P=0.059). Testosterone levels w ere lower in patients with cancer than in the control group, but the d ifferences were not significant. There was no correlation between test osterone levels, tumour stage and ploidy, but the differences in testo sterone level in tumours of a low grade of differentiation compared to those with intermediate and high grade was nearly significant (P=0.05 8). The testosterone/DHT ratio tended to be higher in patients with mo re advanced tumours, SHBG levels were lower in patients with cancer th an in controls but the differences were not statistically significant. There were no systematic variations of tumour stage, grade and ploidy , Multivariate analysis showed that if the PSA level was known, then D HT, testosterone or SHBG added no further information concerning diagn osis, stage, grade or ploidy, Regression analysis on T-stage, PSA leve l and DHT showed an inverse linear relationship between PSA and DHT fo r stage T-3 (P=0.035), but there was no relationship between PSA and t estosterone. Conclusion PSA was of value in discriminating between cas es and controls and between various tumour stages and grades, but no s tatistically significant correlation was found for ploidy. If PSA leve l was known, no other variable added information in individual cases, Within a group, DHT levels tended to be lower among cases and in those with more advanced tumours, There was an inverse relationship between tumour volume, as defined by PSA level, and 5 alpha-reductase activit y, as defined by DHT level, and the testosterone/DHT ratio. This trend was most obvious with T-stage, No systematic variation were found in the levels of testosterone or SHBG.