Endocrine Abstracts

Introduction: The association of thyroid disorders including autoimmune thyroiditis with the risk for breast cancer is controversial (1–4). A recent study found that triidothyronine (T₃) levels are positively associated with breast cancer specific mortality (5). Experimental studies have shown that T₃ mimics the effects of estrogen in human breast cell lines and induces the expression of progesterone receptors (6).

Purpose: The relationship of benign thyroid diseases (BTD) with histopathological alterations of breast tissue diagnosed by biopsy.

Methods: Ninety-three women were followed in an outpatient clinical center for breast diseases (23 premenopausal, 64 postmenopausal and 6 in perimenopausal period). Seventy of them were diagnosed for breast cancer (BC), 20 for benign breast disease (BBD) and 3 for atypia. The history of BTD was determined by medical records and personal interviews. Patients were divided into four groups based on their thyroid functional or morphological status (autoimmune hypothyroidism (10 patients), non autoimmune hypothyroidism (5 patients), hyperthyroidism of any cause (3 patients) and nontoxic goiter (15 patients)). Thyroid hormones functional tests and anti-TPO Ab titres were measured before any surgery or treatment (chemotherapy or radiotherapy).

Results: The overall prevalence of BTD was 22 in 70 (31.4%) women with BC and 8 in 20 women (4%) with BBD (P=0.592). No association to BC or BBD was found when studying each type of BTD separately (P=0.135). These results were independent to thyroid treatment (P=0.594). Mean fT₃, fT₄ and TSH concentrations in women without treatment for BTD, showed no difference between BC and BBD patients (P=0.249, P=0.187, P=0.209 respectively). FT₃ levels were not associated to the concentration of estrogen or progesterone receptors of breast cancer cells (P=0.683). Anti-TPO Ab (>50 U/ml) were not associated to specific histopathological patterns (P=0.641).

Conclusions: Preliminary data show that although overall prevalence of BTD is increased in BC patients compared to patients with BBD the difference was not statistically significant probably due to the small sample.