Background: There is controversy and confusion regarding therapy for patients with ductal carcinoma in situ (DCIS) of the breast. The Van Nuys Prognostic Index (VNPI) was developed to aid in the complex treatment selection process.
Methods: The VNPI combines three significant predictors of local recurrence: tumor size, margin width, and pathologic classification. Scores of 1 (best) to 3 (worst) were assigned for each of the 3 predictors and then totaled to give an overall VNPI score ranging from 3 to 9. Three hundred thirty-three patients with pure DCIS treated with breast preservation (195 by excision only and 138 by excision plus radiation therapy) were studied with detection of local recurrence as the end point.
Results: There was no statistical difference in the 8 year local recurrence free survival in patients with VNPI scores of 3 or 4, regardless of whether or not radiation therapy was used (100% vs. 97%; P = not significant). Patients with VNPI scores of 5, 6, or 7 received a statistically significant 17% local recurrence free survival benefit when treated with radiation therapy (85% vs. 68%; P = 0.017). Patients with scores of 8 or 9, although showing the greatest relative benefit from radiation therapy, experienced local recurrence rates in excess of 60% at 8 years.
Conclusions: DCIS patients with VNPI scores of 3 or 4 can be considered for treatment with excision only. Patients with intermediate scores (5, 6, or 7) show a 17% decrease in local recurrence rates with radiation therapy. Patients with VNPI scores of 8 or 9 exhibit extremely high local recurrence rates, regardless of irradiation, and should be considered for mastectomy.