SRS213 - Less-than-total <i>versus</i> total thyroidectomy for differentiated thyroid cancers measuring 4 cm or less: a systematic review and meta-analysis

Abstract Background Differentiated thyroid cancer (DTC) is common. The 2015 American Thyroid Association guidelines allow total thyroidectomy (TT) or less-than-total thyroidectomy (LTT) for low-risk disease ≤4 cm; comparative outcomes are uncertain. This systematic review and meta-analysis compared LTT versus TT. Methods PubMed, Cochrane Library, Scopus, and Web of Science were searched to October 2024 for adult DTC studies comparing LTT and TT. Outcomes: locoregional recurrence, distant metastasis, reoperation, disease-specific mortality, and postoperative complications (hypocalcemia, recurrent laryngeal nerve [RLN] injury, hematoma/seroma). Random-effects models with I² were used (R 4.4.0). Results Thirty-three studies (n = 37 899; LTT 13 162 [35%], TT 24 737 [65%]; mean age 35–70; follow-up 6–144 months) were included. LTT had higher odds of locoregional recurrence (OR 1.806, 95% c.i. 1.401–2.329; P &amp;lt; 0.001; I² = 48.6) and reoperation (OR 7.174, 95% c.i. 1.232–41.763; P = 0.03; I² = 75.0), with no significant difference in distant metastasis (OR 0.561, 95% c.i. 0.227–1.391; P = 0.21; I² = 0) or disease-specific mortality (OR 0.822, 95% c.i. 0.548–1.234; P = 0.34; I² = 0). Transient complications (hypocalcemia, hypoparathyroidism, RLN injury) were less frequent with LTT (OR 0.139, 95% c.i. 0.079–0.243; P &amp;lt; 0.001; I² = 88.6), as were permanent complications (OR 0.169, 95% c.i. 0.073–0.391; P &amp;lt; 0.001; I² = 74.7). Hematoma/seroma did not differ (OR 0.790, 95% c.i. 0.533–1.170; P = 0.24; I² = 0). Conclusions TT reduces locoregional recurrence but increases postoperative complications compared with LTT. For DTC 1–4 cm, surgical choice should balance oncologic control with complication risk and patient preferences.