PREMORBID BODY-MASS-INDEX IN BREAST-CANCER - REVERSED EFFECT ON SURVIVAL IN HORMONE-RECEPTOR NEGATIVE PATIENTS

The present study consists of 1,238 women with unilateral breast cance r treated with modified radical mastectomy living in the geographic ar ea of Haukeland Hospital. Their weight and height had been measured ye ars before presentation of the disease. Age-adjusted Quetelet's index (weight/height(2)) showed that obese women had a 49% higher risk of dy ing from breast cancer than lean ones. The relative risk decreased sli ghtly when adjusted for tumour diameter, lymph node status, and mean n uclear area of the tumour cells. The prognostic effect of Quetelet's i ndex was examined according to the estrogen and/or progesterone recept or status of the tumour. In patients with a hormone receptor positive tumour, obese women had a risk that was more than three times higher t han lean ones. In patients with hormone receptor negative tumour, the effect of obesity was reversed, lean patients having a risk that was m ore than six times higher than obese ones, even after adjustment for l ymph node status, tumour diameter, and mean nuclear area. Quetelet's i ndex, while being a prognostic variable in its own right, thus acts di fferently in patients with hormone receptor positive and negative tumo urs.