Related Experiment Video
Updated: Jul 13, 2026
Computer-Aided Three-Dimensional Visualization in the Treatment of Locally Advanced Thyroid Cancer
Published on: June 9, 2023
Extrathyroidal extension in well-differentiated thyroid cancer: macroscopic vs microscopic as a predictor of outcome
Amanda Hu1, Jonathan Clark, Richard J Payne
1Department of Otolaryngology, University of Western Ontario, London, Canada, and Royal Prince Alfred Hospital, Sydney, Australia.
Objective:
To examine the prognostic difference in well-differentiated thyroid cancer between macroscopic extrathyroidal extension (ETE), which is appreciated in the operating room, vs microscopic ETE, which is only appreciated under the microscope by the pathologist.
Design:
Retrospective medical record review.
Setting:
Tertiary care academic hospital.
Patients:
Among 582 patients, those who were surgically treated for stage III well-differentiated thyroid cancer with a minimum 5-year follow-up were included. Fifty-five patients (10%) (17 males and 38 females [mean age, 53.1 years]) met the selection criteria.
Main Outcome Measures:
Disease-specific survival and overall survival.
Results:
Thirty-two patients (58%) had macroscopic ETE, while 23 patients (42%) had microscopic ETE. Twenty-year disease-specific survival in the macroscopic group was 47% (8 of 17) and 45% (5 of 11) in the microscopic group (P=.45). Twenty-year overall survival in the macroscopic group was 27% (3 of 11) and 24% (4 of 17) in the microscopic group (P=.59). The only confounding factor was external beam radiation therapy (EBRT). More patients with macroscopic ETE were treated with EBRT (P=.007). When survival was stratified according to EBRT, patients with macroscopic ETE who did not receive EBRT had diminished disease-specific survival (P=.07) and overall survival (P=.12). On multivariate analysis, EBRT was the only predictor of improved disease-specific survival (P=.02) and overall survival (P=.06).
Conclusions:
In selected patients with macroscopic ETE, we recommend postoperative EBRT. Further investigation is required to determine whether macroscopic ETE vs microscopic ETE is an independent predictor of outcome.
