Thyroid

Surgery dominates surveillance of small differentiated thyroid cancer

Surgery dominates surveillance of small differentiated thyroid cancer

The researchers published the study covered in this summary on Research Square as a preprint and it has not yet been peer-reviewed.

Key points to remember

  • Patients with small, differentiated thyroid cancer (DTC) who underwent surgical resection of their tumor had significantly better overall survival (OS) compared to patients who did not undergo surgery but were instead actively monitored.

  • The analyses, which relied on observational data, used propensity score matching and, separately, multivariate adjustment to account for differences between patients who received these two different management strategies.

  • The survival benefit of surgery encompassed all histological types of DTC and was consistent in patients with tumors smaller than 1 cm as well as in those with tumors measuring 1-2 cm.

why it matters

  • The last few decades have seen a rapid increase in the incidence of thyroid cancer in the United States and around the world, most of which are DTCs.

  • The authors said their report is the largest real-world observational study to compare survival outcomes of patients with small DTP between those who underwent surgical resection and those who did not.

  • Most previous studies that have evaluated an active surveillance approach for patients with DTP have focused on patients with papillary thyroid cancer. In the present study, the authors evaluated the survival benefit of surgical resection in patients with any histological type of DTC.

  • The findings underscore the importance of further studies that compare outcomes in patients with small DTP between those managed with active surveillance and those undergoing surgical resection. Additional data from large-scale studies assessing disease-specific survival are needed to assess the benefits and risks of these alternative strategies.

study design

  • The study included adults diagnosed with histologically proven, non-metastatic, small (no larger than 2 cm) DTC in 2004-2016 in the United States. National Cancer Database.

  • The primary endpoint was OS, defined as the time in months between diagnosis and death for any reason.

  • The researchers used Kaplan–Meier survival curves to analyze the OS. They used a log-rank test to assess differences in survival between groups and Cox regression analysis to perform multivariate analyzes to assess factors associated with improved OS. Multivariate analyzes adjusted for facility type, age, gender, race, median household income, education level, insurance status, area, Charlson Comorbidity Indexthe type of histology, the size of the tumor and the state of the surgery.

Principle results

  • The study included 98,501 patients with small, non-metastatic DTP who met enrollment criteria, including having known surgical status; 96,612 (98%) patients were operated and 1,889 (2%) were not operated.

  • The percentage of patients who did not undergo surgery increased over the 13-year period studied, which may reflect increased patient choice for active surveillance.

  • In the unadjusted analysis, patients treated with surgery had significantly better OS, on average 171 months, compared to non-operated patients, on average 134 months.

  • Propensity score matching identified 1889 matched pairs of patients from the subgroups with and without surgery. In this analysis, OS among those who underwent surgery averaged 166 months, significantly better than the average of 134 months in matched patients without surgery.

  • Multivariate analysis showed that surgery significantly reduced the relative risk of death from any cause by 78% compared with no surgery.

  • Several subgroup analyzes showed that the significant benefit of SG associated with surgery persisted regardless of tumor size (< 1 cm or 1-2 cm), histological subtype, or patient age. patient (< 55 years old or ≥ 55 years old).

Limits

  • The database used for the study lacked details about whether patients who did not undergo surgical resection were actively monitored.

  • Other than OS, the National Cancer Database does not contain details of other cancer endpoints such as disease-free survival and cancer-specific survival. It is therefore possible that the higher mortality in patients under surveillance was caused by non-thyroid cancer deaths rather than thyroid cancer deaths, especially given the imbalance in baseline characteristics between the two sub-groups. groups, with older age and more comorbidities in non-surgical patients. It is possible that factors such as age and comorbidity partly explain why some of these patients did not have surgery. To mitigate this limitation, the authors performed multivariate analyzes adjusted for age, comorbidity, and other nonthyroid cancer factors. They performed propensity score matching analysis and also performed several subgroup analyses.

  • The database did not provide details of all high-risk features, such as aggressive histologic subtypes or history of previous neck irradiation.

  • The retrospective nature of the study The National Cancer Database’s data collection methods introduced various types of bias that could affect the precision of the analyzes and the interpretation of the results.

Disclosures

  • The study received no commercial funding.

  • One author, Omar Abdel-Rahman, has served as an advisor to Bayer, Eisai, Ipsen, Lilly and Roche. The other author did not divulge anything.

This is a summary of pre-publication research study, “The role of surgery in small differentiated thyroid cancer,” written by a Cleveland Clinic researcher and a University of Alberta researcher on Research Square, made available to you by Medscape. This study has not yet been peer reviewed. The full text of the study is available at researchsquare.com.