Clinical differences and surgery in follicular vs oncocytic thyroid carcinomas

Area of Science:

• Endocrinology
• Oncology
• Surgical Pathology

Background:

• Follicular thyroid carcinoma (FTC) and oncocytic thyroid carcinoma (OTC) are distinct thyroid cancers with debated optimal management.
• Understanding their differing biological behaviors is crucial for effective treatment strategies.

Purpose of the Study:

• To compare clinicopathological features and treatment outcomes between FTC and OTC based on tumor size.
• To evaluate the impact of total thyroidectomy (TT) and radioactive iodine (RAI) therapy on cancer-specific survival (CSS).

Main Methods:

• Analysis of demographic, clinicopathological, and treatment data from 13,653 patients in the SEER database.
• Kaplan-Meier method, log-rank test, and Cox regression models were used to assess survival and predictors.

Main Results:

• OTC patients were older with higher rates of extrathyroidal extension (ETE) and lymph node metastases (LNM); FTC had higher distant metastasis (DM) rates.
• TT showed no CSS benefit for FTC ≤2 cm or any OTC size. TT was paradoxically linked to worse CSS for FTC >2 cm.
• RAI therapy did not improve CSS for patients with ETE (FTC/OTC) or DM (OTC).

Conclusions:

• FTC and OTC exhibit distinct clinical behaviors influencing treatment response.
• Individualized treatment is recommended, avoiding routine aggressive surgery (TT) or RAI, especially for smaller FTC and all OTC sizes.
• RAI therapy offers limited benefit in OTC, particularly with DM, while TT may be detrimental for larger FTC.