Persistent and recurrent disease in patients with papillary thyroid carcinoma with clinically apparent (cN1), but not extensive, lymph node involvement and without other factors for poor prognosis

Objective Lymph node metastases (LNM) are frequent in patients with papillary thyroid cancer (PTC). The risk of persistent disease (PD) and tumor recurrence (TR) is increased when factors for poor prognosis other than LNM exist, when LNM are numerous, large, detected by preoperative ultrasonography (US), or exhibit extranodal extension. This study evaluated the risk of PD and TR in patients with LNM not exhibiting these characteristics.Subjects and methods Eighty-six patients with 5 or fewer LNM detected during intraoperative inspection, but not by preoperative US, who had no other factors for poor prognosis [tumors > 4 cm, extensive extrathyroid invasion, vascular invasion, aggressive histological subtype, distant metastases, incomplete tumor resection], were studied. All patients underwent total thyroidectomy followed by radioiodine ablation. PD was defined as metastases on initial post-therapy whole-body scans (RxWBS) or detected by imaging methods up to 12 months after ablation. TR was defined as structural disease diagnosed more than one year after ablation in patients without PD.Results PD was diagnosed in 3/86 patients (3.5%). TR was observed in 2/83 patients (2.5%) after 62 months of follow-up. There was no case of death due to the disease. A correlation was observed between pre-ablation Tg and PD or TR [1/48 (2%) with Tg ≤ 2 ng/mL versus 2/22 (9%) with Tg > 2 ≤ 10 ng/mL versus 2/7 (28.5%) with Tg ≥ 10 ng/ml)]. It is noteworthy that 38 patients had up to 3 positive LN and pre-ablation Tg ≤ 2 ng/ml, and none of them had PD or TR.Conclusions The frequency of PD and TR was low in patients with PTC with 5 or fewer LNM and without other factors for poor prognosis. Low postoperative stimulated Tg was predictive of the absence of PD and TR in these patients.

甲状腺乳头状癌（papillary thyroid cancer, PTC）患者中，区域淋巴结转移（lymph node metastases, LNM）较为常见。当存在除LNM外的其他不良预后因素、LNM数量较多、体积偏大、经术前超声（ultrasonography, US）检出或存在结外侵犯时，患者持续性疾病（persistent disease, PD）与肿瘤复发（tumor recurrence, TR）的风险会显著升高。本研究针对不具备上述特征的LNM阳性PTC患者，评估其发生PD与TR的风险。

研究对象与方法：本研究纳入86例患者，这些患者经术中探查发现淋巴结转移数目≤5枚，但术前超声未检出，且无其他不良预后因素[肿瘤直径＞4cm、广泛甲状腺外侵犯、血管侵犯、侵袭性组织学亚型、远处转移、肿瘤切除不完全]。所有患者均接受甲状腺全切术，随后行放射性碘消融治疗。PD定义为消融术后首次治疗后全身扫描（RxWBS）发现转移灶，或消融术后12个月内经影像学检查检出转移灶；TR定义为无PD病史的患者在消融术后1年以上被诊断为结构性病变。

结果：86例患者中3例（3.5%）被诊断为PD。随访62个月后，83例患者中2例（2.5%）出现TR。无患者因该病死亡。消融术前Tg水平与PD或TR存在相关性：Tg≤2ng/mL者中1/48（2%）出现PD或TR，2ng/mL＜Tg≤10ng/mL者中2/22（9%）出现，Tg≥10ng/mL者中2/7（28.5%）出现。值得注意的是，38例患者淋巴结阳性数目≤3枚且消融术前Tg≤2ng/mL，无一例出现PD或TR。

结论：对于存在≤5枚LNM且无其他不良预后因素的PTC患者，其PD与TR的发生率较低。术后低水平的刺激性Tg可预测此类患者不会出现PD与TR。