Introduction: Clinicians often use the Van Nuys Prognostic Index (VNPI) to determine management of ductal carcinoma in situ (DCIS). The VNPI uses age, extent of DCIS, pathological grade and resection margins to stratify patients into three groups pertaining to risk of local recurrence: low-risk (where breast-conserving surgery – BCS – alone appears adequate), intermediate-risk (where BCS plus radiotherapy is recommended) and high-risk (where mastectomy may be the safest option). The purpose of this study was to determine patterns of management of DCIS in Australia and New Zealand according to the VNPI.
Methods: Using the National Breast Cancer Audit for the period 2004–2009, 4578 cases of DCIS were identified where complete data were available. Patterns of management according to the VNPI were determined. The chi-squared test was used for statistical analysis.
Results: In VNPI group 1, 77% of patients were treated with BCS compared with 63% in group 2 and 32% in group 3. Of patients in group 1 who underwent BCS, 58% also received adjuvant radiotherapy, compared with 80% in group 2. In group 3, 68% were treated with mastectomy, and of those who underwent BCS, 86% received radiotherapy. Overall, 23% of DCIS cases did not conform to best practice according to individual VNPI prognostic groupings.
Conclusions: Significant differences in the management of DCIS according to VNPI groups were observed. The results suggest the possibility that some patients in the low-risk group were over-treated, while a proportion of patients in the intermediate- and high-risk groups were under-treated.