Multiple primary thyroid and breast cancer in Israel, 1960-1976.

The occurrence of breast and thyroid multiple primary neoplasms has been evaluated using data from the Israel Cancer Registry. During the 16 years 1960-1976, 3,072 cases of thyroid cancer were registered in Israel. The occurrence of a second primary tumour was reported in 92 of these patients. In this latter group were 25 female patients (27%) with breast cancer, developing synchronously in 7 cases and metachronously in the remaining 18. The average age at the time of appearance of breast cancer was 50 years. Most of the patients (84%) were of European origin. The most common histological types were ductal and intraductal carcinoma and scirrhous adenocarcinoma. The possible aetiological factors common to breast and thyroid cancer are discussed. Efforts aimed at improving the survival of patients with thyroid cancer must incorporate strategies for the early detection and treatment of secondary breast cancer.