Predictive factors of thyroid carcinoma in non-toxic multinodular goitre.

The management of nontoxic multinodular goitre (NMNG) remains controversial. The challenge for the clinician is to identify the small proportion of NMNG patients with associated thyroid carcinoma who would thus benefit from surgery. We studied retrospectively the medical records of 80 patients with NMNG and coexisting thyroid carcinoma who underwent total thyroidectomy. Eighty total thyroidectomy patients with NMNG whose histology was benign were then randomnly chosen as controls. In univariate analysis, the following parameters were significantly more frequent in the carcinoma group: rapid growth of the goitre (p = 0.002), presence of microcalcifications (p = 0.01), hypoechogenicity (p = 0.02), firm consistency of a nodule (p = 0.03), and presence of a dominant cold nodule on scintigraphy (p = 0.03). In the multiple regression analysis, the variables significantly associated with carcinoma were rapid growth (Odds ratio (OR) = 4.13, 95% confidence interval(CI): 1.72-9.89), hypo-echogenicity (OR = 3.11, 95% CI: 1.13-8.51) and the presence of a dominant nodule (OR = 2.26, 95% CI: 1.06-4.79)). In the cancer group, tumour size was positively correlated with compression signs (p = 0.01), age (p = 0.02), the presence of a dominant nodule on scintigraphy (p = 0.02), and with rapid growth (p = 0.04). Concerning nodule size estimated on US (ultrasound), the majority (65%) of patients without carcinoma had nodules < 3 cm, whereas 73% of patients with clinical thyroid carcinoma (> or = 1 cm on histology) had nodules with a diameter of > or = 3 cm on US (p = 0.02). In conclusion, our study suggests that surgical treatment of NMNG should be proposed in the presence of rapid nodular growth, compression signs, dominant nodule on scintigraphy, nodule size > or 3 cm and hypo-echogenicity.