Dedifferentiation of prostate cancer grade with time in men followed expectantly for stage T1C disease

Purpose: We assess whether the Gleason grade changes in men followed expect antly with clinical stage T1c prostate cancer. Material and Methods: We studied 70 men with stage T1c prostate cancer who underwent watchful waiting with repeat needle biopsy sampling to assess for progression. After the initial cancer diagnosis all men had at least 1 oth er biopsy demonstrating cancer. Results: Of 70 cases 9 (12.9%) showed a significant change in grade from Gl eason scores 6 or less to 7 or greater. The average followup of those patie nts without a change in grade was 22 months and greater than those with a c hange in grade. There was no difference between the groups with and without changes in grade in regard to initial prostate specific antigen (PSA), per cent-free PSA, or PSA density or velocity. Of 9 cases there were 5 (56%) an d 8 (89%) with grade change that occurred at 12 and 15 months or less after initial biopsy, respectively. In contrast, only 1 of 24 (4%) patients in w hom last re-biopsy was performed 24 months or greater after the initial can cer diagnosis had a change in grade. Of the 21 men who underwent radical pr ostatectomy 5 (24%) had worsening of grade on the radical prostatectomy spe cimen compared to biopsy, with a mean interval of 18 months between the ini tial cancer diagnosis and prostatectomy. This prevalence of grade change is less than in our population that underwent prostatectomy within 1 to 3 mon ths after biopsy. Conclusions: Because most grade changes occurred relatively soon after biop sy, it implies that tumor grade did not evolve but rather the higher grade component was not initially sampled. During a 1 1/2 to 2-year period after biopsy there is no evidence that prostate cancer grade worsens significantl y. Men with prostate cancer need not feel concerned about waiting several m onths before undergoing surgery after biopsy. Furthermore, men undergoing w atchful waiting can be reassured that there is little evidence that prostat e cancer grade worsens during the short term.