Is mammographic spiculation an independent, good prognostic factor in screening-detected invasive breast cancer?

OBJECTIVE. The aim of this study was to review the prognostic significance of pathologic and radiologic factors for screening-detected invasive breast cancers of any size. MATERIALS AND METHODS. The patient group was a consecutive series of 470 screening-detected invasive breast cancers that were diagnosed between 1988 and 1998. Data regarding tumor type, grade, maximum invasive diameter, lymph node status, and the presence or absence of vascular invasion were recorded, as were the mammographic features of the lesion. Survival was ascertained from hospital records and a cancer registry. Differences in survival were assessed using Kaplan-Meier survival curves with a log-rank test for difference. The significance of any correlations was assessed using the chi-square test and the chi-square test for trend. Multivariate analysis used a Cox proportional hazards model. RESULTS. At univariate analysis, large invasive size, the presence of definite vascular invasion, high histologic grade, and nodal involvement were associated with poorer breast-cancer-specific survival. Mammographic spiculation (the presence of either a spiculated mass or distortion) was associated with more prolonged breast-cancer-specific survival. The presence or absence of mammographic comedo calcification did not influence breast-cancer-specific survival. In a Cox multivariate analysis that included those factors significant in univariate analysis, size, grade, nodal stage, and mammographic spiculation maintained their prognostic significance. CONCLUSION. Mammographic spiculation is an independent, good prognostic factor for screening-detected invasive breast cancer. The mechanism of how mammographic spiculation confers a beneficial prognostic effect is not clear.