[Small thyroid carcinomas: biological characteristics, diagnosis and therapy]

Small thyroid carcinomas (< or = 1.5 cm), including microcarcinomas (< or = 1.0 cm) (n = 39), were found in 53 patients (41%) with a papillary (n = 130) and in 4 cases (4%) with a follicular (n = 110) carcinoma. The tumour was clinically manifested by palpability or by the presence of nodal metastases in 1/3 of patients. Concomitant diagnoses were colloid goitre (n = 24), cellular adenoma (n = 11), Graves' disease (n = 6), and Hashimoto's thyroiditis (n = 4). Nodal involvement, multifocal tumour, and extrathyroidal extent (pT4) were present in 9%, 19%, and 8% of cases respectively. Small follicular carcinomas were minimally invasive in all instances. According to the age-related prognostic TNM-classification, 52 patients (91%) were in the low risk category. 18% of the patients underwent uni- or bilateral partial lobectomy, 35% hemithyroidectomy, and 47% total thyroidectomy, according to the extent and nature of the concomitant benign disease, whereas hemi- or total thyroidectomy was performed in the patients with known cancer. Four of 5 patients with stage pT4 cancer and all patients with nodal involvement underwent total thyroidectomy with radioiodine (n = 8 [14%]). Postoperative morbidity was 0%. During the follow-up period of 1-17 (x = 5.5) years no tumour-related death and no serious recurrence was noted. One node recurrence was removed 1 year following treatment of a stage III pT1aN1b papillary carcinoma; the patient died 4 years later accidentally without residual disease. These results confirm that cases with a potentially favourable course can be defined and treated selectively by less radical measures. Small carcinomas (< or = 1.5 cm) belong to these favourable tumours with a cancer mortality rate of virtually 0%, and the aim of treatment is to prevent curable recurrences: node positivity is an important risk factor, and therefore radioiodine is reserved for carcinomas with nodal involvement and also for the occasional small pT4-tumour.