PRECISION (Cancer Grand Challenges team on DCIS)

PRECISION took on the challenge of distinguishing lethal cancers that need treating from non-lethal cancers that do not, focusing on ductal carcinoma in situ (DCIS). Led by Jelle Wesseling, a pathologist at the Netherlands Cancer Institute, it was funded in 2017 by Cancer Research UK and the Dutch Cancer Society (KWF) through Cancer Grand Challenges, with eight institutions and over 60 researchers in the Netherlands, the UK and the US. Its aims were to understand what drives or prevents progression of DCIS to invasive breast cancer, how to distinguish harmless from hazardous DCIS, and when active surveillance of low-risk DCIS is safe.

The team pooled data and tissue from 47,000 women with DCIS and reports that standard clinical and pathological factors did not predict well enough who could have less treatment; that DCIS size, growth pattern, HER2 status, and COX-2 levels with adipocyte size could help separate lesions; and that about 20 per cent of invasive cancers after surgery for DCIS were unrelated to the original lesion, making DCIS a risk marker for new primary cancers as well as a precursor. In the parallel LORD trial run by the Netherlands Cancer Institute, 76 per cent of women with low-risk DCIS offered a choice chose active surveillance.