Valderrabano P, et al. - Experts ascertained whether or not histologic or clinical outcomes of indeterminate thyroid nodules 4 cm or larger are worse than those for nodules smaller than 4 cm, thus justifying a more aggressive initial surgical approach. Regardless of tumor size, most indeterminate thyroid nodules are benign or low-risk malignant tumors. For most solitary cytologically indeterminate thyroid nodules independent of the tumor size, thyroid lobectomy was seen to be sufficient initial treatment in the absence of other indications for total thyroidectomy.

Methods

• In this retrospective cohort study, researchers consecutively evaluated 652 indeterminate thyroid nodules (546 nodules <4 cm and 106 nodules ≥4 cm) with surgical follow-up at an academic cancer center from October 1, 2008, through April 30, 2016.
• Tumor size was included in the exposure.
• Main outcomes and measures included the differences in cancer rates, rates of invasive features, cancer aggressiveness, and response to therapy between indeterminate thyroid nodules smaller than 4 cm and 4 cm or larger.

Results

• As per data, they studied a total of 652 indeterminate thyroid nodules (546 nodules <4 cm and 106 nodules ≥4 cm) from 589 patients (mean [SD] age, 53.1 [13.8] years; 453 [76.9%] female).
• Results demonstrated no differences in the baseline characteristics of patients or nodules between the 2 size groups.
• Findings did not suggest an association of tumor size with the cancer rate as a categorical (140 of 546 [25.6%] for nodules <4 cm and 33 of 106 [31.1%] for nodules ≥4 cm; effect size, 0.05; 95% CI, 0.002-0.12) or continuous (odds ratio [OR], 1.03; 95% CI, 0.92-1.15) variable.
• Authors did no note a correlation between nodule size and prevalence of extrathyroidal extension, positive margins, lymphovascular invasion, lymph node metastasis, or distant metastasis.
• In both size groups, most malignant tumors were low risk (70% in the nodules <4 cm and 72% in the nodules ≥4 cm), and tumor size was not related to tumor aggressiveness as a categorical (effect size, 0.10; 95% CI, 0.03-0.31) or continuous variable (OR for intermediate-risk cancer, 0.91; 95% CI, 0.72-1.14; OR for high-risk cancer, 1.43; 95% CI, 0.96-2.15).
• Data suggested that at the last follow-up visit in 88 of 105 patients (83.8%) with malignant tumors in the smaller than 4 cm group and 21 of 25 (84.0%) in the 4 cm or greater group no evidence of disease was seen, and tumor size was not associated with response to therapy (effect size, 0.13; 95% CI, 0.07-0.33).