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How do we reconcile what appears to be a more aggressive surgical resection for DCIS than for invasive disease?

NCCN suggests 2 - 4mm margins in DCIS, and no tumor on ink with invasive disease.
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Radiation Oncology · Rutgers Robert Wood Johnson Medical School
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The guidelines panels did an outstanding job in generating both the DCIS and the invasive cancer margins guidelines. It needs to be recognized, however, that despite the sophisticated meta-analysis upon which the recommendations are based, the studies in the meta-analysis had limitations. Appropriat...

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Radiation Oncology · Beth Israel Deaconess Medical Center
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DCIS (or invasive cancers with an extensive DCIS component) appear to spread more widely inside the breast than purely or predominantly invasive cancers. Hence, the residual tumor burden following partial mastectomy is likely larger for the former group than the latter. This likely accounts for the ...

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Radiation Oncology · UNC School of Medicine
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Great discussion and I agree with all of the comments. One item to emphasize is that pathologic assessment of the margin is a “very inexact science.” To the best of my knowledge, there is much variation in how aggressively the margins are assessed (e.g. shaved margins vs. slices taken orthogonal to ...

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Radiation Oncology · Marshfield Clinic - Rice Lake
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There's also a medicolegal angle. If a patient with DCIS recurs and their margins were less than 2 mm, what is your defense when her lawyer asks you why you didn't follow the national guidelines that are based on multiple peer-reviewed trials? That, in your judgement, it wasn't necessary to follow n...

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