A MULTIVARIATE-ANALYSIS OF PROGNOSTIC FACTORS INCLUDING TUMOR RESPONSE AFTER ENDOCRINE THERAPY IN ADVANCED BREAST-CANCER PATIENTS

Although clinicians want to know how tumor response affects the surviv al of advanced cancer patients, the direct comparison of response with survival is severely discouraged because of biases essentially involv ed. In 159 patients with advanced breast cancer treated with adreno-oo phorectomy, we analyzed the survival of the patients using the Kaplan and Meier method with the landmark method (landmark time of 3 months a fter treatment). A multivariate analysis with the Cox proportional haz ard model for survival with explanatory variables including response o f patients at the landmark time (3 months after therapy) was performed in order to find probable prognostic factors. By the Kaplan and Meier curves with the landmark method, response category showed a significa nt difference in the survival of the patients (log rank test; p < 0.00 01). In the Cox model in the patients of landmark time of 3 months aft er therapy, we found that response was the most powerful factor for su rvival out of 10 variables (p = 0.0001), and the dominant site of meta stasis significantly and independently modified the survival length (p = 0.001). ER status was indifferent in the analysis; however, when th e response category was not included, ER was shown to be most influent ial. We propose that a combination of the Cox model with the landmark method would be a rational and useful approach to estimate probable pr ognostic factors including treatment outcome variables such as respons e for the survival analysis in advanced cancer patients.