We present a new prognostic classification designated the Van Nuys classification for ductal carcinoma-in-situ (DCIS). The classification combines high nuclear grade and comedo-type necrosis to predict clinical recurrence. Three groups of DCIS patients were defined by the presence or absence of high nuclear grade and comedo-type necrosis: 1--non-high-grade DCIS without comedo-type necrosis, 2--non-high-grade DCIS with comedo-type necrosis, 3--high-grade DCIS with or without comedo-type necrosis. There were 31 local recurrences in 238 patients after breast-conservation surgery 3.8% (3/80) in group 1, 11.1% (10/90) in group 2, and 26.5% (18/68) in group 3. The 8-year actuarial disease-free survivals were 93%, 84%, and 61%, respectively (all p < or = 0.05). The Van Nuys classification defines three distinct and easily recognisable groups, each of which has a different likelihood of local recurrence if treated with breast conservation.