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

Objectives: 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.

Material And Methods: 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.

Results: 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.

Conclusion: 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.