Body mass index, height and cumulative menstrual cycles at the time of diagnosis are not risk factors for poor outcome in breast cancer

Obesity, height and age at menarche have been shown to be risk factors for the development of primary breast cancer. However, their prognostic influence on breast cancer once it has presented is uncertain. The present study analysed 448 patients with primary breast cancer to determine whether or not body mass index (BMI), height and cumulative menstrual cycles at diagnosis are independent prognostic variables. The effects of all three variables on survival time and disease free interval were estimated. Of the 448 patients after a median follow up of 6 years, 190 (42%) developed recurrence and 162 (36%) had died. Body Mass Index and height could be calculated from available data in 403 patients and cumulative menstrual cycles in 388 patients. There was no evidence of an effect of BMI on survival time (P=0.99; hazard ratio=1.000; 95% Confidence Interval 0.968-1.034) or disease free interval (P=0.92; hazard ratio=1.002; 95% Confidence Interval 0.973-1.031). Similarly, height and cumulative menstrual years did not influence outcome in patients with primary breast cancer. However, nodal status and tumour size were both significant prognostic factors (P<0.001). The present study found no association between Body Mass Index, height and cumulative menstrual years and outcome in patients with primary breast cancer.