Prognostic factors and treatment responses among patients with gross residual disease in differentiated thyroid cancer.

BACKGROUND: Various postoperative staging systems were developed to assess the outcome of differentiated thyroid cancer from initial risk after surgery to dynamic changing prognosis during follow-up. The objective of our retrospective cohort study was to identify risk factors contributing to macroscopic positive surgical margin (R2 resection) and parameters in discriminating the treatment responses and prognosis among R2 patients. METHODS: In total, 242 differentiated thyroid cancer patients with extrathyroidal extension who underwent a thyroidectomy at Kaohsiung Chang Gung Memorial Hospital between January 2013 and July 2018, were included. The patients were grouped according to the presence or absence of gross residual disease (R2). The R2 patients were further classified into two categories according to their treatment response into excellent and nonexcellent groups. The parameters and treatment outcomes were compared between these groups. RESULTS: The mean follow-up time was 45.3 months. Two hundred seven (85.5%) patients had either surgery-free or microscopic margins (R0/R1), while 35 (14.5%) had R2 resection. In the R2 group (n = 35), 15 (42.9%) patients achieved an excellent response, while 20 (57.1%) achieved a nonexcellent response. Statistically significant differences were observed in the extent of neck dissection, TSH-Tg level, post-RAI Tg level, nodal status, and recurrence between the two groups. The Kaplan-Meier curves for 5-year local and distant recurrence-free survival of R0/R1 versus R2 patients were 90.0% versus 66.3%, and 98.4% versus 90.7%, respectively ( p < 0.001). Among the R2 patients, the excellent responders had a higher local recurrence-free survival than nonexcellent responders (93.3% vs. 45.1%, p = 0.008). CONCLUSION: There are significant disparities in recurrence-free survival among R2 patients with different treatment responses. The nodal status of papillary thyroid cancer and thyroglobulin level after thyroidectomy and RAI were factors contributing to difference in their treatment responses.

Recombinant human thyrotropin versus thyroid hormone withdrawal preparation for radioiodine ablation in differentiated thyroid cancer: Experience in a South Taiwanese medical center.

This retrospective study was designed to compare the treatment response of patients with differentiated thyroid cancer (DTC) prepared for radioiodine ablation (RIA) with thyroid hormone withdrawal (THW) or recombinant human thyrotropin (rhTSH) stimulation. Patients with DTC were followed-up retrospectively between 2013 and 2018 in Kaohsiung Chang Gung Memorial Hospital, Taiwan. We compared the excellent response ratios between THW (49.9%) and rhTSH (50.1%) stimulation. Patients were then divided into subgroups, on the basis of age, sex, extrathyroidal extension, lymph node metastasis, and tumor-node-metastasis stage, for analysis. In all, 647 patients were followed-up after RIA. The ratios of THW or rhTSH use in the different subgroups were not statistically significant. In all the patients, the excellent response rate with THW and rhTSH was 80% and 76.5%, respectively, which was not statistically significant. The subgroup analysis, including age, sex, extrathyroidal extension, lymph node metastasis, and tumor-node-metastasis stage (low and high risk), showed similar results. Furthermore, the logistic regression analysis revealed no statistically significant differences among the subgroups. The multivariate analysis showed extrathyroidal extension, lymph node metastasis, and high I131 dose were the prognostic factors affecting the excellent response rate. In conclusion, the THW and rhTSH preparations for RIA were similar in terms of the excellent response rates and subgroup clinical outcomes.