Carcinoma of the thyroid gland in Auckland, New Zealand.

We have reviewed the Auckland experience (1969 to 1987) of 212 instances of carcinoma of the thyroid gland. Females outnumbered males by 4:1, the average age of the patients was 46 years and differentiated cancer was more common (180) than either anaplastic (20) or medullary carcinoma (12). The incidence was higher in the Polynesian patients, most of whom were born outside of New Zealand, than in Maori or European patients, most of whom were born in New Zealand. Patients with papillary carcinoma fared well with greater than 90 per cent of the patients alive at the time of the study, while the corresponding figure for follicular carcinoma was 70 per cent. For both types of differentiated carcinoma of the thyroid gland, the best results, in terms of outcome and morbidity, occurred after total ipsilateral lobectomy and partial contralateral lobectomy (TL + CLPL). In neither type of operation was the use of an adjuvant radioiodine therapy of any obvious benefit. The incidence of permanent complications was twice as high after total thyroidectomy than for TL + CLPL. In contrast with the situation regarding adjuvant radioiodine, patients who presented with systemic follicular carcinomatosis responded well to therapeutic radioiodine, and if thyroidectomy could also be accomplished, the outcome was good. Most patients with anaplastic carcinoma presented with unresectable disease and no regimen used made any impact on the biologic factors of the disease. All but one of the patients with medullary carcinoma had the sporadic variant, and the results were similar after performing either unilateral operation or total thyroidectomy. Carcinoma of the thyroid is more common in Polynesians born in Pacific Islands than in Caucasians or Maoris born in New Zealand. For differentiated carcinoma of the thyroid gland, a satisfactory combination of outcome and morbidity is accomplished with TL + CLPL. Although therapeutic radioiodine is effective in patients with metastatic differentiated carcinoma of the thyroid, we could not show that surgical treatment plus adjuvant radioiodine yielded better results than surgical treatment alone. The major prognostic factors governing the outcome were the histologic type (most patients with papillary carcinoma survive; most patients with anaplastic carcinoma die irrespective of treatment, and patients with follicular and medullary lesions have an in-between outlook) and the presence of systemic disease. The presence of regional disease did not appear to influence the outcome.(ABSTRACT TRUNCATED AT 400 WORDS)