The prognostic value of serum thyroid-stimulating hormone level post-lobectomy in low- and intermediate-risk papillary thyroid carcinoma.

BACKGROUND: This study was undertaken to determine the optimal thyroid-stimulating hormone (TSH) value associated with structural recurrence in patients with low-risk or intermediate-risk papillary thyroid carcinoma (PTC) who underwent thyroid lobectomy. METHODS: Patients with PTC (n = 1047) who received thyroid lobectomy and central compartment node dissection were included in the study. RESULTS: Structural recurrence occurred in 42 of the patients (4.0%), and no patient died of PTC. Multivariate analysis showed a primary tumor size (with a cut-off of 0.85 cm) and serum TSH level measured 1 year after the initial surgery (cut-off 1.85 mU/L) independently predicted structural recurrence. CONCLUSIONS: TSH levels during the early postoperative period need to be monitored and maintained in the lower normal range even in patients with low- or intermediate-risk PTC undergoing thyroid lobectomy.

Dynamic risk stratification system in post-lobectomy low-risk and intermediate-risk papillary thyroid carcinoma patients.

OBJECTIVE: The dynamic risk stratification (DRS) and its current definition of each response-to-therapy category in post-lobectomy papillary thyroid carcinoma (PTC) patients have not been well studied. This study aimed to validate the DRS system and to investigate useful thyroglobulin (Tg) or anti-Tg antibody (Ab)-related parameters in defining each response-to-therapy category. DESIGN: Retrospective observational study. PATIENTS: This historical cohort study included 619 patients with PTC treated by thyroid lobectomy. MEASUREMENTS: All enrolled participants were stratified according to the American Thyroid Association (ATA) initial risk stratification system and DRS system, respectively. The association between these stratifications and structural recurrence was evaluated. RESULTS: The median follow-up period was 103 months. Structural recurrence occurred in 1.6% of the patients with excellent response, 3.8% of those with indeterminate response, 2.9% of those with biochemical incomplete response, and all patients with structural incomplete response. Five (1.5%) of the low-risk patients and 14 (5.0%) of the intermediate-risk patients had structural recurrence. The disease-free survival curves showed significant differences according to the DRS (P < .001) and ATA initial risk stratification (P = .012), respectively. The proportion of variance explained the DRS system and ATA risk stratification system for structural recurrence was 32.4% and 29.4%, respectively. A thyroid-stimulating hormone (TSH) level >2.75 µU/mL at 1 year after the initial operation (P < .001) was the only valuable risk factor for structural recurrence identified in this study. CONCLUSION: The long-term postoperative management of PTC patients treated with thyroid lobectomy could be guided based on the DRS.

Dynamic Risk Stratification in Stage I Papillary Thyroid Cancer Patients Younger Than 45 Years of Age.

BACKGROUND: This study validated the dynamic risk stratification (DRS) system with regard to its association with structural recurrence and risk factors associated with non-excellent responses in patients <45 years with stage I classical papillary thyroid cancer (PTC). METHODS: This historical cohort study included 598 patients with stage I classical PTC <45 years of age treated with total thyroidectomy followed by radioactive iodine remnant ablation (n = 440), total thyroidectomy without radioactive iodine remnant ablation (n = 23), and thyroid lobectomy alone (n = 135). RESULTS: The median follow-up period was 123 months. Structural recurrence occurred in 4.2% (n = 18/432) of the patients with an excellent response, 17.1% (18/105) of patients with an indeterminate response, 44.7% (17/38) of patients with a biochemically incomplete response, and 82.6% (19/23) of patients with a structurally incomplete response (p < 0.001) during the follow-up. The disease-free survival curves of each response showed significant differences (p < 0.001). Extensive extrathyroidal extension and extranodal extension were the independent risk factors associated with non-excellent response (p < 0.05). CONCLUSIONS: DRS may reduce unnecessary additional treatments by reclassifying initial risk estimates of structural recurrence. Furthermore, applying the risk factors associated with non-excellent response to initial therapy may be a more useful and viable surrogate of the risk for structural recurrence in stage I PTC patients <45 years of age.

Is Male Gender a Prognostic Factor for Papillary Thyroid Microcarcinoma?

BACKGROUND: Male gender is a prognostic factor of poor outcome in papillary thyroid carcinoma (PTC). We investigated the prognostic role of male gender in papillary thyroid microcarcinoma (PTMC). METHODS: We included 2930 patients who underwent surgery at Asan Medical Center for PTC. Clinicopathologic characteristics from the patients' medical records were compared for male and female PTC patients. Independent prognostic factors for recurrence in PTC and PTMC were evaluated after propensity score matching analysis. The median follow-up period was 82 months. RESULTS: Recurrence and death were more common in male patients with PTC than in female patients with PTC (12.6 vs. 9.6%, p = 0.03 and 2.2 vs. 0.6%, p < 0.001, respectively). However, there was no difference in disease-free survival between male and female PTMC patients (p = 0.57). Multivariate analysis after propensity score matching revealed that male gender is not an independent prognostic factor of recurrence in PTMC (hazard ratio [HR] 1.5, 95% confidence interval 0.75-5.33, p = 0.17), but that it is an independent prognostic factor in PTC >1 cm (HR = 3.06, 95% confidence interval 1.34-6.98, p = 0.008). CONCLUSIONS: Male gender is an independent prognostic factor for recurrence in PTC >1 cm, but it is not a prognostic factor in PTMC.

Prognostic Impact of Further Treatments on Distant Metastasis in Patients With Minimally Invasive Follicular Thyroid Carcinoma: Verification Using Inverse Probability of Treatment Weighting.

BACKGROUND: The aim of this study was to evaluate the prognostic impact of further treatments in minimally invasive follicular thyroid carcinoma (MIFTC) patients. METHODS: The risk factors for distant metastases were analyzed, and the impact of surgical extent on distant metastasis was verified by using weighted logistic regression models with inverse-probability of treatment weighting (IPTW). RESULTS: 166 patients including 31 males (18.7 %) and 135 females (81.3 %), with the mean age of 41.5 ± 13.5 years, were enrolled for this study. The median follow-up period was 103.5 months (range, 13-244 months). Seven patients (4.2 %) had distant metastases during follow-up period. The presence of vascular invasion (Hazard ratio [HR] = 29.06; 95 % Confidence Interval [CI] = 3.06-209.08; p = 0.015) and extensive vascular invasion ≥4 foci (HR = 40.57; 95 % CI = 2.09-789.13; p = 0.014) were the independent risk factors for distant metastasis by multivariate analysis. Surgical extent did not influence distant metastasis. Logistic regression with IPTW also demonstrated that there were no statistically significant differences in the development of distant metastasis based on surgical extent (HR = 1.28; 95 % CI = 0.15-10.87; p = 0.823). CONCLUSIONS: The presence of extensive vascular invasion is the most powerful predictor of distant metastasis. However, it is noteworthy that further treatments do not demonstrate an advantageous effect on preventing distant metastasis during the follow-up period.

Initial and Dynamic Risk Stratification of Pediatric Patients With Differentiated Thyroid Cancer.

Background: The objective of this study was to evaluate the usefulness of American Thyroid Association (ATA) risk classification and dynamic risk stratification (DRS) based on the response to initial therapy in pediatric patients with differentiated thyroid cancer (DTC). Methods: This historical cohort study included 77 pediatric patients with DTC who underwent thyroid surgery. Clinical outcomes during median 5.3 years of follow up were assessed according to 3 ATA risk groups and 4 DRS groups. Results: In ATA risk classification, 22%, 48%, and 30% of patients were in the low-, intermediate-, and high-risk groups, respectively. There was no significant difference in disease-free survival (DFS) between the indeterminate and the low-risk group. The risk of recurrent/persistent disease was significantly higher only in the high risk group [hazard ratio (HR), 18.4; P = 0.005]. In DRS, 49%, 13%, 6%, and 31% of patients were classified in the excellent, indeterminate, biochemical incomplete, and structural incomplete response groups, respectively. The risk of recurrent/persistent disease was significantly higher in the indeterminate group (HR, 10.2; P = 0.045) and in the structural incomplete group (HR, 98.7; P = 0.005) compared with the excellent response group. Conclusions: DRS based on the response to initial therapy could be useful in addition to initial ATA pediatric risk classification to predict recurrent/persistent disease in pediatric patients with DTC.

Oncologic Safety of Robot Thyroid Surgery for Papillary Thyroid Carcinoma: A Comparative Study of Robot versus Open Thyroid Surgery Using Inverse Probability of Treatment Weighting.

The aim of this study was to evaluate the oncologic safety of robot thyroid surgery compared to open thyroid surgery for papillary thyroid carcinoma (PTC). We enrolled 722 patients with PTC who underwent a total thyroidectomy with central compartment node dissection (CCND) from January 2009 to December 2010. These patients were classified into open thyroid surgery (n = 610) or robot thyroid surgery (n = 112) groups. We verified the impact of robot thyroid surgery on clinical recurrence and ablation/control-stimulated thyroglobulin (sTg) levels predictive of non-recurrence using weighted logistic regression models with inverse probability of treatment weighting (IPTW). Age, sex, thyroid weight, extent of CCND, and TNM were significantly different between the two groups (p < 0.05); however, there was no significant difference in recurrence between the open and robot groups (1.5% vs. 2.7%; p = 0.608). The proportion of patients with ablation sTg < 10.0 ng/mL and control sTg < 1.0 ng/mL was comparable between the two groups (p > 0.05). Logistic regression with IPTW using the propensity scores estimated by adjusting all of the parameters demonstrated that robot thyroid surgery did not influence the clinical recurrence (OR; 0.784, 95% CI; 0.150-3.403, p = 0.750), ablation sTg (OR; 0.950, 95% CI; 0.361-2.399, p = 0.914), and control sTg levels (OR; 0.498, 95% CI; 0.190-1.189, p = 0.130). Robot thyroid surgery is comparable to open thyroid surgery with regard to oncologic safety in PTC patients.