The medical legal implications of following mammographic breast masses.

Delay in breast cancer diagnosis continues to account for the highest percentage of medical malpractice cases in the United States. A retrospective, computer-aided study was undertaken to investigate a number of parameters used in making medical-legal decisions in missed breast cancer cases. Over a 5-year period, 435 women with invasive breast cancers were registered at the Comprehensive University Breast Cancer Center. A close correlation between mammographic and final histologic size was verified (R = 0.74). In 5-mm increments, starting with a 1.0-mm tumor, there was an increasing percentage of positive nodes identified with increasing size of the tumor. Major percentage increases in frequency of positive nodes were noted at tumor sizes of 11 and 21 mm. This corresponded to an increasing number of recurrences and a decreasing 5-year disease-free survival (DFS) between consecutive 5-mm increments, although the differences were not significant. A multivariate regression analysis confirmed that the most important predictor of DFS was lymph node status (p = 0.0046) and not tumor size. After adjusting for lymph node status, tumor size was not significant. It is concluded that a period of observation, in which a breast cancer may increase in size is not substandard care since tumor size, after accounting for lymph node status is not significant at predicting DFS.