For women with multicentric ER+ non high-grade DCIS excised with negative margins, is breast conservation with whole-breast radiation and a boost to each lumpectomy bed reasonable?

It is reasonable, in my view, to irradiate patients with multiple ipsilateral primaries (including DCIS) who have had adequate excision of each lesion, rather than to perform mastectomy. There are many studies supporting this approach. However, there are three issues to consider in these patients to...

Provided negative margins obtained for the 2 lesions and acceptable cosmesis, I would be okay with this approach. Respecting the whole breast dose constraints as outlined in the trial would be important. The majority of patients in that trial had 2 lesions. I would be less comfortable if there were ...

I would treat with whole breast followed by boost based on risk factor as long as pre op imaging is adequate and satisfactory.