Low-grade screen-detected ductal carcinoma in situ progresses more slowly than high-grade lesions: evidence from an international multi-centre study

Purpose Nuclear grade is an important indicator of the biological behaviour of ductal carcinoma in situ (DCIS). De-escalation of treatment has been suggested for low-grade DCIS. Our aim is to estimate the relative rate of progression of DCIS by nuclear grade by analysing the distribution of nuclear grade by detection at initial or subsequent screening.