诊断性131I全身扫描联合术后疗效反应评估助力甲状腺乳头状癌豁免131I治疗的前瞻性队列研究OA

Background and purpose:Radioactive iodine(RAI)therapy is a critical adjuvant therapy for papillary thyroid carcinoma(PTC)following surgery.However,current decision-making regarding RAI therapy primarily relies on static recurrence risk stratification at a single time point.Postoperative response evaluation can compensate for the limitations of static risk stratification by providing an objective and accurate assessment of real-time disease status.This prospective study aimed to investigate the feasibility of omitting RAI therapy in non-low-risk PTC patients without distant metastasis,utilizing diagnostic ¹³¹I whole-body scan(DxWBS)combined with postoperative response evaluation,thereby providing evidence for refined RAI management strategies.Methods:This prospective cohort study was approved by the ethics committee of Peking Union Medical College Hospital(ethical approval number:ZS-2790)and registered in the Medical Research Registration and Filing Information System of the National Health Information Platform(registration No.MR-11-22-013518).This study enrolled postoperative patients with thyroid cancer who attended the outpatient clinic of the Department of Nuclear Medicine,Peking Union Medical College Hospital between January 2018 and April 2023.Inclusion criteria:① Age≥18 years;② All patients underwent total thyroidectomy,regardless of whether concomitant cervical lymph node dissection was performed or the type of neck dissection involved;③Postoperative histopathology confirming PTC;④ Postoperative stimulated thyroglobulin(Tg)≤10 ng/mL[stimulated is defined as a measurement obtained at a thyroid-stimulating hormone(TSH)level≥30 mIU/L];⑤ Postoperative thyroglobulin antibody(TgAb)≤115 IU/mL;⑥ Initial postoperative DxWBS revealing non-specific findings[including no residual thyroid tissue(absence of iodine-avid foci in the neck exceeding the uptake levels of the salivary glands or gastric mucosa),residual thyroid tissue only(presence of an iodine-avid focus in the midline of the neck,reported as residual thyroid tissue or thyroglossal duct remnant)and suspected lymph nodes(presence of an iodine-avid focus in the anterior cervical region,reported as residual thyroid tissue not excluding concurrent metastatic lymph nodes)];⑦ Recurrence risk stratified as low-to-intermediate,intermediate-to-high,or high risk according to the 2025 American Thyroid Association(ATA)guidelines.Exclusion criteria:① Patients undergoing reoperation(non-initial surgery);② Patients with a prior history of RAI therapy;③ Patients presenting with distant metastasis prior to surgery;④Patients with other tumors or other comorbidities that could affect survival.All patients were fully informed of the potential benefits and risks of ¹³¹I therapy at the outpatient clinic,voluntarily chose whether to receive ¹³¹I treatment,and completed follow-up.Fisher's exact test was used for association analysis,and Kaplan-Meier analysis with the log-rank test was used to compare event-free survival between groups.A two-sided significance level of α=0.05 was set,and P<0.05 was considered statistically significant.Results:A total of 92 patients were included(49 in the observation group and 43 in the RAI therapy group).Except for T stage,there were no statistically significant differences in baseline characteristics(including age,gender,N stage,tumor size,extrathyroidal extension,ATA recurrence risk stratification and best response)between the two groups(all P>0.05).The median follow-up durations were 58.6 months for the observation group and 55.5 months for the RAI therapy group,respectively.The incidence of outcome events was 0.0%in the observation group and 4.7%in the RAI therapy group,with no statistically significant difference detected by Fisher's exact test(P=0.216).Kaplan-Meier analysis revealed highly overlapping event-free survival curves;The 1-,3-and 5-year event-free rates were 100.0%vs 100.0%,100.0%vs 100.0%and 100.0%vs 94.4%,respectively(log-rank χ²=2.602,P=0.107).Subgroup analyses stratified by ATA risk and best response consistently showed no significant differences in outcome event rates between the two groups(all P＞0.05).Conclusion:For non-low-risk PTC patients without distant metastasis who had non-specific findings on DxWBS and a postoperative response evaluation of excellent response(ER)or indeterminate response(IDR),omitting RAI therapy was not observed to increase the risk of recurrence in this cohort.Nevertheless,the non-randomized nature of this study may introduce selection bias,limiting causal conclusions.Additionally,the small number of high-risk patients warrants careful interpretation.