In deciding whether to treat prostate cancer or merely observe it, the issue of a worsening of Gleason score over time has loomed large. If the Gleason score worsens, the risk of waiting should be greater. Prior studies had suggested that about a third of prostate tumors untreated will show a worsening of Gleason score. Now a large study from Harvard Medical School at Brigham and Women’s, the Harvard School of Public Health and Dana Farber suggest that for most patients the Gleason score does not change. The authors contend further that the Gleason score is set by the genetics of the cancer, i.e., the key mutations that caused it to begin with. Click here for the abstract; email Dr. Stark for the entire article (copyright laws prevent a direct link). The methodology are complex but relate to changes in tumor stage versus Gleason score when comparing patients diagnosed before and after PSA screening became widespread. Dr. Stark weighs in: For patients this information is important. It lessens the risk of waiting. In the litigation arena it helps clarify the impact of a delay in the diagnosis of prostate cancer. If the results had shown otherwise, plaintiff’s attorneys could claim that a delay in diagnosis worsened the client’s outlook. Now this is more difficult. These are difficult data to collect: most men who choose so-called active surveillance don’t have serial prostate biopsies. Where this has been done as part of a study, there is the risk of sampling error from one year to the next. This paper is an important contribution to this evolving field when it comes to who can afford to wait.