Skip to main content
SSO 2024 Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Presentation Icons
Recorded for On-Demand Viewing
Recorded for On-Demand Viewing
Back

Endocrine

Endocrine/Head & Neck Parallel Session

35: Re-Evaluation of the Importance of Tumor Size in Surgical Decision-Making for Well-Differentiated Thyroid Cancer

Thursday, March 21, 2024
10:47am – 10:57am ET
Location: C102
Disclosure(s):
Jesse E. Passman, MD MPH: No financial relationships to disclose
Introduction: Well-differentiated thyroid cancer (WDTC) is a common yet indolent malignancy. Given high disease-specific survival, recent trends in management have emphasized de-escalation of care, including more limited resection for low-risk tumors. In this study, we evaluate the role of tumor size >4 cm as a prognostic feature in WDTC in order to further guide surgical decision-making.


Methods: Patients who underwent surgery for WDTC were identified from the Surveillance, Epidemiology and End Results database (2008 – 2013). Patients were categorized by tumor size and presence of high-risk features (HRF; e.g., extrathyroidal extension, regional metastases). Propensity score matching and multivariable Cox proportional hazards models were used to assess the relationship between tumor size and survival. Effect modification between tumor size and HRF was analyzed across the total cohort via multivariable Cox modeling with interaction terms. Cutpoint analysis using Harrell’s C-index was performed to determine the size cutoff associated with the greatest increase in risk.


Results:

12,164 patients were included. The median age was 64 years (IQR 58 – 70). 82.8% were White, and 71.3% were female. 10.5% had tumors >4 cm (median tumor size 1.2 cm), and 32.4% had at least one HRF. Disease-specific 5-year survival was 98.3% (95% CI 98.1% – 98.5%). Patients with tumors >4 cm had worse 5-year survival than those with tumors < 4 cm (93.0% vs. 98.9%, p< 0.001).

Across all patients, increasing tumor size (HR 4.16, 95% CI 3.12 – 5.53, p< 0.001), age >55 years (HR 2.79, 95% CI 1.47 – 5.30, p=0.020), male sex (HR 1.49, 95% CI 1.11 – 1.95, p=0.007), and Medicare insurance (compared to Medicaid: HR 3.32, 95% CI 1.22 – 9.07, p=0.019) were associated with worse survival. After matching on other covariates, tumor size >4 cm was associated with increased mortality compared to size < 4 cm (HR 3.21, 95% CI 2.00 – 5.60, p< 0.001). Tumor size >4 cm with concomitant HRF demonstrated worse survival than tumor size >4 cm alone (MMD 0.17, p< 0.001) and other HRF alone (MMD 0.19, p< 0.001), however these effects were not further modified by an interaction between tumor size and HRF (p=0.222). Cutpoint analysis demonstrated the largest increase in hazard of death at tumor size ≥2 cm.


Conclusions: Tumor size was directly related to risk of mortality in WDTC, with the greatest increase in risk at >2 cm. Concomitant HRF were associated with worsened survival but did not synergistically interact with tumor size. Further investigation should be performed regarding the interaction between size, HRF, and mortality.

Learning Objectives:

  • describe the influence of tumor size on survival in well-differentiated thyroid cancer.
  • discuss the interaction of high-risk features and tumor size on prognosis in well-differentiated thyroid cancer.
  • integrate new evidence regarding tumor size and high-risk features into their clinical decision-making regarding extent of resection in well-differentiated thyroid cancer.