Analyzing the Risk of Recurrence after Mastectomy for DCIS: A New Use for the USC/Van Nuys Prognostic Index

Abstract

Patients with ductal carcinoma in situ (DCIS) who are treated with mastectomy seldom recur locally or with metastatic disease. When patients with DCIS recur with invasive cancer, they are upstaged and their lives are threatened. We questioned whether histopathologic data could be used to predict these infrequent events. We reviewed a prospective database of 1,472 patients with pure DCIS. All patients were scored from 4 to 12 using the USC Van Nuys Prognostic Index, an algorithm based on DCIS size, nuclear grade, necrosis, margin width, and patient age. Probabilities of recurrence and death were calculated using the Kaplan-Meier method. A total of 496 patients with pure DCIS were treated with mastectomy. None received any form of postmastectomy adjuvant treatment. Average follow-up was 83months. Eleven patients developed recurrences, all of whom scored 10-12 using the USC/VNPI. No patient who scored 4-9 recurred. All 11 patients who recurred had multifocal disease and comedo-type necrosis. The probability of disease recurrence after mastectomy for patients scoring 10-12 was 9.6% at 12years, compared with 0% for those scoring 4-9. There was no difference in overall survival. There were no recurrences among mastectomy patients who scored 4-9 using the USC/VNPI. Patients scoring 10-12 were significantly more likely to develop recurrence after mastectomy. At risk were young patients with large, high-grade, and multifocal or multicentric tumors. For every 100 patients with USC/VNPI scores of 10-12, 10 patients will recur by 12years and 2-3 will develop metastatic disease.