Can Tumor Biology Predict Occult Multifocal Disease in Breast Cancer Patients?

The SHAVE trial is a prospective trial in which 235 women with stage 0 to 3 disease undergoing partial mastectomy were randomized intraoperatively to either have cavity shave`s (CSMs) taken at the time of initial surgery or not. In this study, 9 of the 76 patients (11.8%) with initially negative margins randomized to the "shave" group had occult cancers found in the CSM. Seven of these patients had sufficient primary tumor tissue available for further analysis. These patients were age and stage matched in a 1:2 ratio to other patients in the trial who had no further disease found in their CSM. A tissue microarray was created, stained for E-cadherin, MUC1, and beta-catenin, and evaluated by two independent pathologists (blinded to outcome). There were no significant differences between cases and controls in terms of median invasive tumor size, ductal carcinoma in situ size, volume of initial resection, and volume of CSM. Further, no differences were noted between cases and controls for median (staining intensity × per cent of cells staining) for each marker. Hence, although nearly 12 per cent of breast cancer patients with negative margins will have occult disease, this could not be predicted by primary tumor markers in this study.