Microscopic Positive Tumor Margin Increases Risk for Disease Persistence but Not Recurrence in Patients with Stage T1-T2 Differentiated Thyroid Cancer

Using a CT-based scale to evaluate disease extension and the resectability of locally advanced thyroid cancer

OBJECTIVES

To establish a computed tomography (CT)-based scale to evaluate the resectability of locally advanced thyroid cancer.

METHODS

This twin-centre retrospective study included 95 locally advanced thyroid cancer patients from the 1st centre as the training cohort and 31 patients from the 2nd centre as the testing cohort, who were categorised into the resectable and unresectable groups. Three radiologists scored the CT scans of each patient by evaluating the extension to the recurrent laryngeal nerve (RLN), trachea, oesophagus, artery, vein, soft tissue, and larynx. A 14-score scale (including all comprised structures) and a 12-score scale (excluding larynx) were developed. Receiver-operating characteristic (ROC) analysis was used to evaluate the performance of the scales. Stratified fivefold cross-validation and external verification were used to validate the scale.

RESULTS

In the training cohort, compromised RLN (p < 0.001), trachea (p = 0.001), oesophagus (p = 0.002), artery (p < 0.001), vein (p = 0.005), and soft tissue (p < 0.001) were predictors for unresectability, while compromised larynx (p = 0.283) was not. The 12-score scale (AUC = 0.882, 95%CI: 0.812-0.952) was not inferior to the 14-score scale (AUC = 0.891, 95%CI: 0.823-0.960). In subgroup analysis, the AUCs of the 12-score scale were 0.826 for treatment-naïve patients and 0.976 for patients with prior surgery. The 12-score scale was further validated with a fivefold cross-validation analysis, with an overall accuracy of 78.9-89.4%. Finally, external validation using the testing cohort showed an AUC of 0.875.

CONCLUSIONS

The researchers built a CT-based 12-score scale to evaluate the resectability of locally advanced thyroid cancer. Validation with a larger sample size is required to confirm the efficacy of the scale.

CLINICAL RELEVANCE STATEMENT

This 12-score CT scale would help clinicians evaluate the resectability of locally advanced thyroid cancer.

KEY POINTS

• The researchers built a 12-score CT scale (including recurrent laryngeal nerve, trachea, oesophagus, artery, vein, and soft tissue) to evaluate the resectability of locally advanced thyroid cancer. • This scale has the potential to help clinicians make treatment plans for locally advanced thyroid cancer.

A comparative analysis of treatment efficacy in intermediate-risk thyroid cancer

PURPOSE

This study aimed to evaluate the efficacy of different treatment combinations on patient survival in intermediate-risk differentiated thyroid cancer (DTC).

METHODS

The 2004-2017 National Cancer Database was queried for intermediate-risk papillary (PTC), follicular (FTC), or Hurthle cell (HTC) thyroid cancer patients. Four treatments were analyzed using Kaplan Meier and multivariable Cox regression: surgery, surgery with adjuvant radioiodine ablation (S + RAI), surgery with adjuvant thyroid-stimulating hormone suppression therapy (S + THST), and S + RAI + THST. Kaplan-Meier and multivariable Cox proportional-hazards analyses evaluated treatment-associated overall survival (OS).

RESULTS

Of 65,736 patients, 72.2% were female and the average age was 45.4 ± 15.4 years. The 10-year OS rates for PTC, FTC, and HTC were 93.2%, 85.2%, and 78.5%, respectively. S + RAI + THST exhibited higher OS than surgery alone and S + RAI (all p < 0.05). Compared to surgery alone, S + RAI + THST demonstrated reduced mortality in PTC (Hazard Ratio [HR]: 0.628, p < 0.001), FTC (HR: 0.490, p < 0.001), and HTC (HR: 0.520, p = 0.006). Similarly, adjuvant RAI + THST reduced mortality regardless of lymphovascular invasion (HR: 0.490, p < 0.001), N1a (HR: 0.570, p < 0.001) or N1b metastasis (HR: 0.621, p < 0.001), or positive margin status (HR: 0.572, p < 0.001).

CONCLUSIONS

Treatment combinations demonstrated varying efficacies in intermediate-risk DTC depending on histology and tumor characteristics, with S + RAI + THST exhibiting the greatest treatment response.

Predictors of persistent disease following initial thyroid cancer management

OBJECTIVES

To study which factors increase the risk of persistent disease in differentiated and poorly differentiated thyroid carcinoma. Methods: A retrospective chart review of all consecutive differentiated and poorly differentiated thyroid cancer patients from King Abdulaziz University Hospital, Jeddah, Kingdom of  Saudi Arabia, a tertiary care center, between 2004 and 2018. Logistic regression analysis was performed to predict factors associated with less than excellent response to treatment. Results: We included 186 patients with complete data records; 81.1% were females. Papillary thyroid carcinoma comprised 88.1% of the neoplasms. In total, 55.9% of patients attained an excellent response to treatment by the end of the first year following treatment. All patients with distant metastasis had persistent disease. On univariate analysis, female gender was associated with excellent response (p=0.002). Lymph node metastasis, extrathyroidal extension, vascular invasion, and cancer multifocality were all found to be inversely related to excellent response (p less than 0.05 for all). On multivariate analysis only lymph node metastasis was associated with a decreased adjusted odds of an excellent response (p=0.007). Conclusion: Patients with lymph node metastasis are at high risk for persistent disease following initial thyroid cancer management. Careful monitoring of these patients is warranted.