[Differentiated carcinoma of the thyroid gland in an area of endemic goiter. Clinical study and prognostic correlation].

OBJECTIVE

Differentiated thyroid Carcinoma is a relatively frequent malignant neoplasia with three histologic types: papillary, follicular, and Hürtle cell carcinoma. Although papillary is the most common type, in endemic goitre areas the frequency of follicular type increases. Up to now, the only European studies about clinical aspects of differentiated thyroid carcinoma in endemic goitre areas are those performed in the Bavarian region until 1983. As the province of Orense (assistance zone concerning to the Hospital Virgen del Cristal) is a zone of endemic goitre, we have analyzed clinical presentation features and prognostic correlation factors in patients with differentiated thyroid carcinoma living in this area.

DESIGN

Retrospective study. Variables analyzed: 1) Age. 2) Sex. 3) Histologic type. 4) Tumor size. 5) Stage. 6) Presence of multinodular goitre. 7) Posttherapeutic disease persistence. 8) Recurrence. 9) Distant metastases. 10) Death attributed to thyroid carcinoma.

PATIENTS

61 cases of differentiated thyroid carcinoma, detected from 1983 to 1993. Mean follow-up period: 5 years (minimum 1, maximum 21). All patients were treated with total thyroidectomy followed by radioiodine ablation.

RESULTS

67.2% of papillary, 31.2% of follicular and 1.6% of Hürtle cell carcinoma. Male/female ratio: 1/4. Mean age: 48.8 +/- 2.9 (M +/- ESM) in papillary and 55 +/- 3.2 in follicular. Tumor size was smaller in papillary: 2.2 +/- 0.2 vs 6.2 +/- 0.5 cm (p < 0.001). Papillary type was detected more frequently than follicular in stages I, II and III, whereas follicular prevailed in stage IV (p < 0.03). Positive correlation between age and size in papillary: r = 0.393 (p < 0.01) and similar tendency in follicular: r = 0.423 (p = 0.057). Multinodular goitre was more frequent in follicular: 47% vs 25% (p = 0.02). Free of disease cases after treatment: 81% of papillary (p < 0.05) and 42% of follicular. Stage correlated independently with disease persistence after treatment (p = 0.0006). Age was minor in free of disease group: 50.0 +/- 3.8 vs 65.3 +/- 3.8 (p = 0.01).

CONCLUSIONS

In our area, papillary is the most common type, but follicular proportion is higher than reported from non endemic goitre areas. PC is a small tumor detected in stage I, whereas FC is large and detected in stage IV. Tumor stage is an independent prognostic factor. Frequent presence of multinodular goitre in patients with differentiated thyroid carcinoma suggests that in zones of endemic goitre, clinical attitude in multinodular goitre and solitary nodule must be similar.