[Differentiated thyroid cancers. 20 years' results of a protocol based on simple prognostic criteria]

To study the long-term results of an aggressive management protocol based on a new-simple classification and to determine the duration for patient follow-up according to this classification.

For the 509 patients with differentiated thyroid carcinoma, the classification was: group 1: cancer < 1 cm (n = 117), group 2A: cancer without extension in patients of age less than 45 years (n = 100), group 2B: cancer without extension in patients aged more than 45 (n = 94), group 3: cancer with nodal extension alone (n = 102), group 4: high risk cancer in patients having either distant metastases or local tissular extension or in whom after iodine-131 ablation, Tg level was > 3 micrograms/l off hormone therapy (n = 96). Total thyroidectomy was the rule except for group 1 and some patients of group 2A in whom the tumor was solitary, relatively small, well-differentiated, with no capsular or capillary invasion. Iodine 131 ablation was carried out after a total thyroidectomy and repeat treatments with iodine 131 were given whenever necessary.

In group 1, 2A and 3, the 20 years death rate of cancer was 0 p. 100. For group 2B, patients cancer death rate was 8 p. 100 and for group 4 it was 32 p. 100. Distant metastases were the cause of death except for one patient who died from local recurrence. Clinical inspection, Tg measurement, iodine 131 whole-body scan and chest X-ray were all useful in discovering local or distant recurrences.

Our results justify the use of an aggressive initial management for differentiated thyroid carcinoma and an appropriate scoring system. When this protocol is applied, patients of group 1, 2 and 3 should have an excellent prognosis. However patients follow-up should not be shorter than 15 years for patients of group 1 and 2A and than 20 years for all other groups.