April 24, 2018

Clean versus Dirty? When to be concerned about cancer

Dogs14Most surgeons and oncologists think that the Goodman/Enneking system is fading in popularity and any “clean but close” nomenclature is too imprecise for systematic use. So what’s the new system all about? I think of them like this:

R0 (complete resection, as you said, with negative* margin)

*Negative here is really going with the KISS principle.  It means tumor does not touch ink.  If you are 1 mm away from ink, that is negative.

R1 (grossly negative margin, as you said.  You leave the operating room believing your margin to be negative.  But the pathologist sees tumor abutting ink.  So any microscopically positive margin, at any location in the specimen is R1.  There is no wiggle room, no gray area – it is simply a tumor cell abutting ink.)

R2 (Incomplete excision/Grossly positive margin.  R2 is identified in surgery.  You either have tumor spillage, inadvertently enter the tumor, or have a margin that you can tell grossly is positive.)

I like this system because we really don’t know where to draw the line for a “close” margin and a “close” margin for one tumor is an adequate margin for another.  I also find this system simpler to use clinically because it doesn’t leave the client having to figure out what the gray areas mean.  You can be more definitive in your recommendations.

– “The margin is clean.  We shouldn’t need any further treatment but we will need surveillance.”  R0 where you are happy with the magnitude of the margin.

– “Although the margin is clean, I’m afraid this is a nasty tumor.  I’m going to recommend some adjuvant treatment” R0 where you deem it to be too close for comfort.

– “We thought the margin would be clean but the pathologist sees an area under the microscope where the margin is dirty.  We need to do _______.”  R1