What resection margins are required for DCIS with a component of invasive disease?

The SSO-ASTRO-ASCO guidelines of 2016 on margin status for patients with tumors that are pure DCIS or predominantly DCIS requiring a minimum of 2 mm for those receiving RT were based on a meta-analysis of (mostly older) published studies, not individual patient data. Three much more recent studies f...

Based on guidelines.

Once invasive disease there, negative margin is no tumor at ink margin.

For pure DCIS with RT, aim for 2 mm margin but not absolute as need to look at the global picture before planning reexcision. If margin less, would boost for sure.

For no RT even through RTOG aim for 3 mm, i...

For patients with pure DCIS who will be receiving adjuvant RT, our practice is to follow the SSO-ASTRO-ASCO Consensus Guidelines (Morrow et al., PMID 27528719) with the goal of 2 mm or greater margins. Occasionally, patients with <2 mm margins will be discussed in a multidisciplinary manner and re-e...

I follow a similar practice to Dr. @Dr. First Last. I thought that Drs. Pilewskie and Morrow wrote a nice article on this subject with a review - PMID 29338088.

Ultimately --

1. Invasive + DCIS, follow invasive margin guidelines. The biology of the invasive is the primary concern in this patient.
2. DCIS w...

In the RTOG 9804 DCIS study, we had three categories of margin width, 3mm-9mm, 10mm or greater, or “negative on re-excision.” All patients were stratified by those margin categories, and we found no relationship between local recurrence and margin width. So for a patient with pure DCIS, I accept the...