Introduction, evolution, and application of the Van Nuys prognostic index in DCIS

In general, patients with ductal carcinoma in situ (DCIS) are offered breast-conserving treatment (lumpectomy with radiation) versus mastectomy. Given the varying presentations of DCIS as well as the broad biologic spectrum of disease, many investigators have, over time, sought to identify subgroups of patients who could potentially have surgical resection alone as the definitive means of treatment, thus sparing the patient from radiation and its associated risks. The University of Southern California/Van Nuys Prognostic Index (USC/VNPI) was created in 1996 and subsequently revised as a means of stratifying DCIS cases based on independent predictors of local recurrence. The original model used tumor size, margin width, and pathologic classification (nuclear grade and presence or absence of comedonecrosis) to create a tool to identify patients that could possibly avoid radiation after breast-conserving surgery versus those with high-risk factors for local recurrence for which more aggressive therapy was recommended. The goal of this prognostic index was to provide a reproducible and objective model that could be used to standardize the treatment decision-making process and avoid confusion among patients and clinicians. It has since been modified to include age as independent prognostic predictor. While this initial attempt at using known prognostic factors for DCIS to create a uniform approach to treatment decision making among a very heterogeneous group of lesions seems very feasible, even the authors admitted that this tool should be viewed as an "adjunct" and not a substitute for sound clinical judgment by the clinician and informed patient consent. The development of the VNPI was the first and most widely cited effort to address the local recurrence rates among particular subsets of DCIS patients with similar biologic activity. Although this model gained early success, in recent years it has been criticized based on the fact that it was derived from retrospective analysis and has not been validated in a large prospective randomized trial. Further avenues that warrant exploration include the possibility of adding genomic markers to the tool to strengthen its validity.