Is the presence of mammographic comedo calcification really a prognostic factor for small screen-detected invasive breast cancers?

AIM: It has been suggested that the use of traditional prognostic factors such as histological grade and lymph node stage are not reliable predictors of outcome for small (< 15 mm diameter) screen-detected breast cancers. It has also been suggested that the presence of mammographic comedo (casting) microcalcifications may be an important prognostic factor. We have determined prognostic factors for small screen-detected cancers in a univariate and multivariate fashion. MATERIALS AND METHODS: Histological grade, lymph node stage, invasive tumour size and vascular invasion status was obtained on 161 consecutive patients with primary invasive breast cancer < 15 mm diameter, detected by screening. The Nottingham Prognostic Index was calculated for each patient. The mammograms were assessed for the presence of microcalcifications, these being classified as either comedo or non-comedo. Survival data was also obtained. RESULTS: Overall survival in this group of patients was excellent with only 12 patients (7.5%) dying from their breast cancer (mean follow-up 7.5 years). Univariate analysis showed a significant association between lymph stage and outcome (x(2) = 9.68, P = 0.008). No significant association was demonstrated between the presence of comedo calcification and survival. Multivariate analysis confirmed lymph node stage as the only independent prognostic factor for these small screen-detected breast cancers (x(2) = 7.18, P = 0.007). There were significant associations between the presence of comedo calcification on the screening mammogram and high histological grade and small tumour size. CONCLUSION: Although the overall outcome for small screen-detected breast cancers (< 15 mm diameter) is excellent, the presence of lymph node metastases is associated with a significant reduction in long-term survival. The presence of mammographic comedo calcification is not an independent prognostic factor, but is closely related to histological grade. (C) 2003 The Royal College of Radiologists. Published by Elsevier Science Ltd. All rights reserved.