Positive surgical margins — “déja vu all over again”
Posted Feb 10 2010 12:00am
It is educational to compare the data from the Mayo Clinic, published just the other day, with data just reported by the University of Michigan, which show a clear association between the presence of positive surgical margins and disease-free patient survival in prostate cancer patients.At a quick glance it might seem as though the two sets of data are contradictory and that the ongoing issue of what a positive surgical margin actually implies may be unending. In fact, these two sets of data are closely supportive.
Lake et al. reviewed data from 2,468 patients who were treated with radical prostatectomy at the University of Michigan between January 1996 and October 2008. In conducting their data analysis, they classified the patients into three groups: those with negative surgical margins (NSMs); those with focal positive surgical margins (FPSMs) — defined as ≤ 3 mm; and those with extensively positive surgical margins (EPSMs) — defined as > 3 mm. They then compared the probabilities of disease-free survival (DFS) among the patients with differing surgical margin status.
Their results showed the following:
Among the overall group of 2,468 patients, 2,022 (82 percent) had NSMs, 344 (14 percent) had FPSMs, and 99 (4 percent) had EPSMs.
Of the 1,997 patients with pT2 disease, 1,716 (86 percent) had NSMs, 229 (11.5 percent) had FPSMs, and 52 (2.6 percent) had EPSMs.
The 10-year DFS was 84, 64, and 38 percent for all patients with NSMs, FPSMs, and EPSMs, respectively.
The 10-year DFS for organ-confined disease was 90, 76, and 53 percent for patients with NSMs, FPSMs, and EPSMs, respectively.
The authors conclude that (a) the risk of biochemical recurrence for all patients increases with worsening margin status and that (b) margin status affects biochemical recurrence and depends on the Gleason grade on surgical pathology for all patients and for patients with pT2 (organ-confined) disease.
If you go back to look at the data reported by the Mayo Clinic, the authors of that study also clearly state that there was a close correlation between positive surgical margins and biochemical recurrence. The difference is that they report on overall and cancer-specific survival as well as just biochemical recurrence. What we need to know now is whether the data from the University of Michigan — like the data from the Mayo Clinic — suggest that the presence of positive surgical margins is not a significant predictor of systemic cancer progression, prostate cancer-specific death, and overall mortality. It may take a while to do that.
What the University of Michigan data also do is to give us some ideas about how to think about the appropriate management of men with positive surgical margins, based on the size and number of those margins. Clearly those patients with extensively positive surgical margins (EPSMs) tended to relapse with much greater frequency that patients with a focal positive surgical margin (FPSM). Does the presence of EPSMs predict for systemic cancer progression, prostate cancer-specific death, and overall mortality?