Premorbid body weight and its relations to primary tumour diameter in breast cancer patients; its dependence on estrogen and progesteron receptor status

Hormonal mechanisms have been offered as an explanation for the higher freq uency of large tumours, lymph node metastases and poorer prognosis in obese breast cancer patients than in lean ones. If hormonal mechanisms are impor tant for these relations, they should probably act more strongly in patient s with hormonal receptor positive tumours than in those with negative ones. We have examined if the relations between premorbid body weight or Quetele t's index (weight/height(2)) and tumour diameter are modified by estrogen r eceptor alpha (ER) and progesteron receptor (PgR) status. The analyses were based on 1,241 women with unilateral disease treated with modified radical mastectomy living in the geografic area of Haukeland Hospital. Their body weight and height have been measured as a mean 12.5 years before presentati on of the disease. Body weight and Quetelet's index have been adjusted for age. The relations were studied using linear regression analyses adjusting the effect of body weight with height and mean nuclear area of the tumour c ells and adjusting the effect of Quetelet's index for mean nuclear area. Th e main findings showed that patients with high body weight or Quetelet's in dex presented more often with PgR positive tumours than lean ones. Quetelet 's index was also positively related to ER. These relations were present in patients older than 50 years of age (older). Patients with large tumours ( >2.0 cm) had significantly higher body weight and Quetelet's index than tho se with small ones. These differences were significantly present in older p atients and in patients with PgR negative and ER negative - PgR negative tu mours. Linear regression analyses confirmed that tumour diameter increases with body weight and Quetelet's index. These relations were present in both lymph node groups and in older patients. Stratification according to hormo nal receptor status showed these relations to be significant in patients wi th ER negative, with PgR negative and those with ER negative - PgR negative tumours only. Taking age and hormonal receptor status into consideration s imultaneously, both body weight and Quetelet's index were significantly rel ated to tumour diameter in older patients with hormone receptor negative tu mours. In conclusion body size was positively related to hormone receptor s tatus and to diameter of the primary tumour. The relation to tumour diamete r was present in older patients with hormone receptor negative tumours. Alt hough hormonal mechanisms able to act on the tumour can not be excluded, me chanisms acting independent of hormonal receptors must be considered. Diffe rent mechanisms related to body fat cytokines are discussed.