Ductal carcinoma in situ (DCIS): USC/Van Nuys Prognostic Index (VNPI) and the impact of micropapillary histotype

662 Background: As our knowledge of DCIS has evolved during the past decade, treatment decision making has become much more complex and controversial. We examined the use of VNPI and the effectiveness of micropapillary histotype as a predictor of local recurrence (LR). Methods: We retrospectively collected 408 patients treated from 1988 to 2002 for DCIS or microinvasive DCIS (mi-DCIS), with conservative surgery or mastectomy according to the VNPI. We added to the classic VNPI the micropapillary histotype: with this novel algorithm, score 1 was given to micropapillary DCIS (M-DCIS) G1 and to other histotypes G1–2, while score 3 was given to M-DCIS G2–3, and to other histotypes G3 and/or to mi-DCIS. Finally, we compared sensitivity and specificity of the two prognostic indexes. Results: DCIS was diagnosed in 337 patients and mi-DCIS in 71 women. 267 patients underwent conservative surgery, while 141 underwent mastectomy (96 after a conservative surgery). Adjuvant radiotherapy was given in 58% of conservativ...