Correlation between the DCIS score and traditional clinicopathologic features in the prospectively designed E5194 clinical validation study.

Abstract

1005 Background: We previously reported that in the E5194 clinical trial patients with ductal carcinoma in situ (DCIS) treated with wide local excision (WLE) without radiation (RT), the DCIS Score was significantly associated with 10 year risk of an ipsilateral breast event (IBE - recurrence of in situ or invasive carcinoma), whether evaluated as a continuous or categorical variable (P=0.02 for both). Here we evaluate correlation between DCIS Score and clinicopathologic (CP) features and if DCIS Score provides independent recurrence risk information. Methods: The study population included 327 women with DCIS prospectively selected for treatment with WLE without RT, including low-intermediate grade tumors ≤2.5 cm or high-grade ≤1 cm. CP variables included age, menopausal status, tamoxifen treatment (used in 29%) and expert centrally determined tumor size, grade, comedo necrosis, tumor type, and margin status. The association between DCIS Score and CP variables was examined by spearman rank correlation, and proportional hazards regression models were used to determine variables significantly associated with IBE. Results: Lesion size (p=0.009) and menopausal status (p=0.03) were significantly associated with IBE, while grade (p=0.69) and comedo necrosis (p=0.47) were not. DCIS Score was significantly associated with IBE after adjustment for CP features and tamoxifen use (p=0.02). DCIS Score was moderately correlated with grade (rs=0.46; 95% CI 0.37,0.54), percentage comedo necrosis (rs=0.49; CI 0.41,0.57), and lesion size (rs=0.18; CI 0.08,0.29) but not other features. Exploratory analyses in all CP subgroups, including the multicomponent Van Nuys Prognostic Index, showed a wide range of DCIS Scores in each subgroup. Concordance of the grades among readers was low: local vs parent central, 68%; local vs central nuclear grade, 45%; parent central vs central nuclear grade, 37%. Conclusions: DCIS Score is moderately correlated with grade, comedo necrosis, and tumor size. DCIS Score provides recurrence risk information independent of these features and identifies subjects with DCIS who are at high risk for local invasive and in-situ local recurrence after WLE alone.