Obesity, estrogen production, and tumor estrogen receptors in women with carcinoma of the breast

The poor prognosis of obese women with carcinoma of the breast has yet to find a satisfactory explanation. It is suspected that the hormonal milieu of these patients may favor tumor growth. This investigation explored the relationship between obesity, urinary estrogen excretion, and tumor estrogen receptors (ER) in women treated with mastectomy for carcinoma of the breast. The ER levels determined from the primary cancers of 129 women treated with mastectomy were compared with the obesity index (O.I.) of these patients, i.e., weight in pounds/height in inches. In addition, 24-hour total urinary estrogen determinations were performed in 30 postmenopausal women and compared with their O.I. and ER. A weak direct correlation was found between ER and O.I. in postmenopausal women. The urinary estrogens of postmenopausal women were correlated directly with obesity index, but no relationship could be established between urinary estrogens and the ER content of breast cancers. It is concluded that the excess estrogen production of obese women may be responsible for their poor prognosis by promoting tumor growth. The high tumor ER concentrations associated with obesity suggest a high frequency of hormonally sensitive tumors.