Leftovers.

Pathologic complete response (pCR) is an important outcome for trials of neoadjuvant therapy for breast cancer. That’s because it is consistently associated with survival outcomes. So what does it mean when there is residual ductal carcinoma in situ (DCIS) on final path? This retrospective look at specimens from the prospective IPSY-2 trial says no. Of 337 women with pCR, DCIS was present in 21% of specimens overall: 9% of triple-negative, 16% of ER+, and 37% of HER2+ cancers. Unlike the degree of residual invasive disease, residual DCIS had no bearing whatsoever on local control, distant control, or overall disease control, perhaps in part because these cases receive adjuvant radiation per initial clinical staging. | Osdoit, JAMA Surg 2022