Closest Surgical Margin
When attempting conservative breast surgery (CBS) by palpation, ultrasound, dye
localization, or needle (using one or more wire needles) localization, the goal is to attempt
to totally remove the DCIS cancer plus a surrounding border or rim of breast tissue which is
negative for tumor. The "margin status" parameter in the VNPI calculation is the
microscopically measured thickness of the thinnest place in that surrounding rim of
uninvolved [no cancer] breast tissue. Our personal experience over the past ten years is that
this can be an exasperatingly difficult measure to obtain. The pathologist MUST use some
degree "gut feeling" about this parameter as he/she takes into consideration the known
mammographic shape of the lesion, the handling of the lumpectomy through the making of a
specimen X-ray, and the character of the tissue as it is coated with margin-marking dye prior
to slicing with knife or razor blade [some tissue specimens are highly fatty and margins
easily disrupted during surgery, X-raying, or knife slicing]. So, the surgeon and/or the
pathologist may "know" that the margins are clear by a greater thickness than can be "proven"
on the permanent, final pathology slides.
The reason that you don't
see us actually calculate the VNPI in pathology reports is that it is tough for us pathologists to
be independently sure about the exact figures for size and margin parameters. Remember that 10mm.
equals 1.0 cm.
- closest/thinnest
measured margin is equal to or greater than 1.0 cm..........................1
point.
- closest/thinnest
measured margin is between 0.1-0.9 cm................................................2
points.
- closest/thinnest
measured margin is less than 0.1 cm........................................................3
points.
VNPI SCORE= tumor-size pts x 0.749 [_____] plus nuclear pts x 0.869
[_____]
plus margin pts x 0.864 [_____]=_____total VNPI
points
[BACK TO VNPI PAGE] or to
calculation
table
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(posted 17 Dec. 2000)
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