Value of the Van Nuys Prognostic Index in prediction of recurrence of ductal carcinoma in situ after breast-conserving surgery

Background: The Van Nuys Prognostic Index (VNPI), an algorithm based on tumour size, tumour grade, presence of necrosis and excision margin width, is claimed to predict local recurrence after breast-conserving surgery for ductal carcinoma in situ (DCIS). The aim of this study was to examine the validity of the VNPI in a UK population. Methods: Clinicopathological data, including VNPI subgroups, for 237 patients who had breast-conserving operations for DCIS were examined. Multivariate data analysis was performed using a Cox regression model to examine the independence and relative importance of different variables in predicting recurrence, and to compare the data with those used in derivation of the VNPI. Results: The median follow-up was 47 months. There were 37 ipsilateral local recurrences. Excision margin width (P<0.001) and tumour grade (by Van Nuys grading (P=0.014) or simple nuclear grading (P=0.004)) were the only independent risk factors for local recurrence. Excision margin width had three times more power than grade in predicting local recurrence. Subgrouping data by VNPI score predicted recurrence-free survival (P<0.001), but stratified 78 per cent of patients into a group with a moderate risk of local recurrence. Conclusion: Excision margin width is the most important predictor of local recurrence after breast-conserving surgery for DCIS. The VNPI lacked discriminatory power for guiding further patient management.