It is possible to screen for medullary thyroid cancer (MTC) with biochemical tests, imaging and genetic testing in families with multiple endocrine neoplasia type 2. The recommendation is based on a consensus statement made by the Members of the European Community concerted action for MTC. The prognostic characteristics are based on 117 patients with MTC diagnosed in Denmark between 1970-1991. Twenty percent of all MTC patients were members of families with two or more thyroid cancer patients. More than half of all MTC patients had neck lymph node involvement at the time of diagnosis. The frequency of neck lymph node involvement was however only 20% amongst those with familiar MTC.