Prostate specific antigen levels in the follow up of localised prostate cancer: how does radiotherapy compare to radical prostatectomy?

This study aimed to evaluate tumor progression as assessed by PSA level of curative treatment for localised prostate cancer by either radiotherapy or prostatectomy. From 1987 to 1993, 180 patients were treated for clinically localised prost ate cancer either by radiotherapy or prostatectomy. One hundred and Eve pat ients with clinical T1T2N0M0 were eligible for this study. Forty five under went external beam radiotherapy and 60 had a radical prostatectomy. After r adiotherapy PSA slowly decreased to reach a nadir 18 months after treatment . Any subsequent increase from this lowest post treatment level is associat ed with tumor progression. After radical prostatectomy PSA becomes undetect able and any increase will be regarded as evidence of tumor progression. The median PSA level before treatment and the median length of follow-up we re comparable for the two groups. There was no statistically significant di fference in overall survival and biological evidence of disease progression at 5y. Analysis of the evolution of median PSA level shows a progressive d ecline during the 4y after radiotherapy. After radical prostatectomy PSA be come undetectable, 4y after treatment PSA levels become comparable in the t wo groups. The biochemical free survival was 60% for the prostatectomy grou p and 62% for the radiotherapy group. PSA is an effective marker of tumour progression after surgery or radiother apy for localised prostate cancer. In our retrospective study recurrence ra tes at 5y were not significant but direct comparisons are limited due to th e Gleason score of the two groups. PSA levels can take up to 4y to reach a nadir after radiotherapy.