Papillary and follicular thyroid cancer: impact of treatment in 1578 patients.

We report the experience from 13 Canadian radiotherapy centres concerning the treatment and outcome for 1074 papillary and 504 follicular thyroid cancer patients followed for 4-24 years. Surgical resection was carried out in almost all patients; there was no correlation between the type of operation and recurrence or survival. Treatment with external irradiation (201 patients) radioiodine (214 patients), or both (107 patients) was used more often in poor prognosis patients than in those with good prognostic factors, and was effective in reducing local recurrences and improving survival, especially in patients with microscopic residual disease postoperatively. Treatment complications were common but rarely fatal. Thyroid cancer was the cause of death in over half of the papillary cancer deaths and in two-thirds of the follicular cancer deaths.