Do you use a tumor-bed boost following whole breast irradiation for patients with DCIS?

We do use a tumor bed boost following whole breast RT, with the rationale and principle being similar to invasive cancer. The benefit is probably higher in younger patients and higher grade disease. The prospective study from Tasmania may help quantify the benefit

Good question as we are lacking prospective data on this topic while awaiting TROG 07.01. In the absence of prospective data, I generally omit a boost in DCIS with the exception of women <50 with high grade DCIS (as per criteria used in RTOG 1005) or women with DCIS who present with a palpable mass.

DCIS is often associated with higher recurrence rates than invasive cancer (see NSABP and consortium results). The French did find that boosts were associated with lower recurrence rates. For this reason, I would err on the side of a boost.

However, survival is unlikely to be impacted by recurrence...

According to the most recent 2018 ASTRO guidelines on whole breast published in PRO A tumor bed boost may be omitted in patients with DCIS who, if age >50 years, meet the following criteria: screen detected, total size ≤2.5 cm, low to intermediate nuclear grade, and widely negative surgical margins ...