A DIRECT RELATIONSHIP BETWEEN THYROID ENLARGEMENT AND BREAST-CANCER

Despite extensive study, evidence to support a direct relationship bet ween diseases of the thyroid and breast has not been established. In t his study thyroid volume was assessed by ultrasound in 200 patients wi th breast cancer and 354 with benign breast disease. Results were comp ared to appropriate female control groups. Both mean thyroid volume (2 1.1 +/- 1.4 mL) and the percentage of individual patients with enlarge d (>18.0 mL) thyroid glands (41.5%) were significantly greater in the breast cancer group than equivalent values (13.2 +/- 0.5 mL and 10.5%, respectively) in age-matched controls (P < 0.01 in both cases). The m ean thyroid volume of 14.5 +/- 0.34 mL in patients with benign breast disease was also significantly greater than that of 12.5 +/- 0.38 mL i n younger controls (P < 0.01). The results support a direct associatio n between breast cancer and increased thyroid volume as mean thyroid v olumes and the percentage of individual patients with enlarged thyroid glands were similar in those studied both before (20.8 +/- 1.3 mL and 43.0%) and after (21.4 +/- 1.6 mL and 40.0%) therapies for breast can cer. Although there is no evidence that thyroid enlargement represents a risk factor for breast cancer, the results emphasize the importance of raising the consciousness of the coincidence of both disorders.