Nobuyuki Wada

OBJECTIVE: To determine the frequency and pattern of lymph node metastasis (LNM) from papillary thyroid microcarcinoma (PTMC) and the results of node dissection, and to establish the optimal strategy for neck dissection in these patients. SUMMARY BACKGROUND DATA: Most PTMCs carry a favorable prognosis, but a few present with palpable lymphadenopathy. Patients with LNM are at risk for nodal recurrence, although they do not have higher mortality. The frequency and pattern of LNM from PTMC and the results of node dissection are not well established. METHODS: The frequency and pattern of LNM from 259 PTMCs were analyzed according to the size and location of the primary tumor. Of the 259, 24 with palpable nodes underwent therapeutic node dissection and the other 235 patients without palpable nodes underwent prophylactic node dissection. The authors compared the results of node dissection between the therapeutic group and the prophylactic group, and between PTMCs 5 mm or smaller and PTMCs larger than 5 mm. The authors also compared nodal recurrence between the prophylactic group and a no-lymph-node-dissection group (155 PTMCs). RESULTS: Overall, 64.1% (166/259) and 44.5% (93/209) had node involvement of the central and ipsilateral lateral compartment, respectively. Pretracheal (43.2%), ipsilateral central (36.3%), and ipsilateral mid-lower (37.8%) jugular were more commonly involved. LNM was more frequent in the therapeutic group than in the prophylactic group (95.8% vs. 60.9% for central compartment, 83.3% vs. 39.5% for ipsilateral lateral compartment). Nodal recurrence was more common in the therapeutic group than in the prophylactic group (16.7% vs. 0.43%), but did not differ between the prophylactic group and the no-dissection group (0.43% vs. 0.65%). The tumor size did not influence nodal recurrence. Nodal recurrence preferentially occurred in ipsilateral mid-lower jugular nodes. CONCLUSIONS: Patients who have PTMC presenting with palpable lymphadenopathy should have therapeutic node dissection. Prophylactic node dissection is not beneficial in those without palpable lymphadenopathy.

Preoperative sestamibi (MIBI) and ultrasonography (US) are used to localize parathyroid tumors in patients with primary hyperparathyroidism (pHPT). The intraoperative quick PTH assay (qPTH) has been recommended to determine whether all hyperfunctioning parathyroid tissue has been removed. We questioned whether qPTH improves the results of parathyroidectomy in patients with pHPT. We analyzed 115 unselected patients with pHPT without a family history or multiple endocrine neoplasia but who had undergone parathyroidectomy. All 115 patients had successful operations without complications. Of these patients, 88 (77%) had solitary adenomas, 13 had double adenomas, 1 had triple adenomas, 12 had hyperplasia, and 1 had carcinoma. Overall, MIBI was correct in 72% (76/106), US in 49% (49/99), and qPTH in 80% (92/115). For preoperative studies showing a single tumor, MIBI was correct in 83% (73/88), US was correct in 71% (45/63), and combined MIBI and US were correct in 95% (37/39). Adding qPTH in this subgroup did not improve the successful focused approach: 70% for MIBI, 65% for US, and 87% for combined MIBI and US. However, adding qPTH improved the overall success of parathyroidectomy (MIBI 92%, US 86%, combined MIBI and US 97%), but at the cost of unnecessary further exploration (MIBI 13%, US 6%, combined MIBI and US 8%). We conclude that when the same solitary tumor is identified by both MIBI and US, a focused exploration can be done with a 95% success rate. Adding qPTH to MIBI or US can improve the success rate but at a significant cost. General exploration of all parathyroid glands, however, has the highest success rate (100%).