Clinical characteristics in sporadic and familial medullary thyroid carcinoma. A nationwide study of 249 patients in Sweden from 1959 through 1981.

All patients with medullary thyroid carcinoma (MTC) diagnosed in Sweden during 1959 through 1981 were recruited for study from the Swedish Cancer Registry. Among a total of 249 patients, 66 were diagnosed in 1959 through 1969 and 183 from 1970 through 1981. Apparently sporadic MTC was present in 186 patients, and familial MTC in 63. Twenty-seven patients with familial MTC were diagnosed from clinical symptoms and 36 by screening. In both the sporadic group and the symptomatic familial group, approximately 80% of the patients had palpable thyroid tumors. Lymph node metastases were present in 44% of the sporadic group and in 37% of the group with symptomatic familial MTC, and distant metastases in approximately 20% of the patients in each of these groups. The patients detected by screening differed significantly from the two groups of symptomatic cases by having a lower frequency of palpable thyroid lesions (50%), smaller tumors, and lower frequencies of cervical lymph node metastases (14%) and distant metastases (0%). Multivariate analyses revealed no significant differences between sporadic cases and symptomatic familial cases regarding tumor size or stage. Large tumors (greater than 3 cm) were more frequently accompanied by palpable cervical lymph nodes and were associated with an approximately four times higher risk of distant metastases than tumors smaller than 1 cm. Women had significantly smaller tumors and a more favorable stage distribution than age-related men.