An improved statistical approach: can it clarify the role of new prognostic factors for breast cancer?

Recently, there has been a proliferation of new biomarkers, some of which may lead to an improved prognostic index or may influence treatment selection. However, there are methodological and statistical issues that require attention in assessing the role and use of these prognostic factors. Between 1977 and 1986, 1097 primary breast cancer patients were accrued for multidisciplinary research at the Henrietta Banting Breast Centre, Women's College Hospital; follow-up to 1990 is complete for 96% of the patients. Data for these patients are used here to illustrate strategies: (1) for the comparison of results from diverse assessments of biomarkers; (2) for the improved comparability of inter-laboratory results; (3) for the examination of the results from monoclonal or polyclonal antibody assays for possible clinically relevant bimodality; (4) for good statistical resolution of overlapping distributions; (5) that involve the use of quantitative values for prognostic factors whenever possible; and (6) for improved multivariate analyses. Good data handling and analyses may enable more accurate and rapid assessment of new prognostic factors, thereby expediting and improving their clinical application.