Thyroid malignancy in endemic nodular goitres: prevalence, pattern and treatment.

Aims: The epidemiology of thyroid cancers in goitre endemic zones has not been recently reviewed, and changes being currently reported have been from studies in non-endemic areas. The aims of this study were to present the clinical pattern of thyroid malignancy in a goitre endemic area and identify recent changes, if any.

Methods: The study was conducted at Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria between January 1983 and December 1993. Records of patients with nodular goitres treated with thyroidectomy were reviewed, and the clinical features, laboratory parameters, treatment, outcome and follow-up of histologically-proven malignant cases were studied.

Results: Thirty-six of 279 (12.9%) patients, aged 13-85 years (mean)=43.7+/-14.7 years), carried malignant goitres, and most (80%) were young or middle-aged women. Of the well-differentiated cancers, follicular type was the most prevalent, being six- and 12-fold as frequent as papillary and medullary cancers (69%vs 11% and 5.6%), respectively. Lymphoma accounted for 5.6%, fibrosarcoma, 5.6% and anaplastic, 2.8%. No relationship was demonstrable between cancer type, duration of goitre and age at diagnosis (r=0.06 and 0.17, respectively).

Conclusions: Thyroid cancers afflict comparatively young women in our environment, and follicular cancer remains the predominant type, partly as a result of persisting dietary iodine deficiency.