Lymph node metastases in differentiated thyroid cancer under 2 cm.

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Differentiated thyroid cancer (DTC) is a common endocrine malignancy.
• T1 stage DTC involves tumors less than or equal to 2 cm.
• The prognostic significance of lymph node metastasis in T1 DTC requires further evaluation.

Purpose of the Study:

• To assess the prevalence of lymph node metastasis in T1 DTC.
• To determine the correlation between tumor characteristics and lymph node metastasis.
• To evaluate the prognostic impact of lymph node metastasis on tumor recurrence and cancer-related death.

Main Methods:

• Prospective review of 551 T1 DTC patients from a tumor registry.
• Patients underwent thyroidectomy and standard radioactive iodine ablation.
• Analysis included logistic regression and actuarial estimates for recurrence and death.

Main Results:

• 45% of T1 DTC patients had lymph node metastasis.
• Tumor size (0-2 cm) did not predict lymph node metastasis.
• Vascular invasion, soft tissue invasion, and multifocal disease correlated with positive lymph nodes.
• Positive lymph nodes were associated with a higher recurrence rate (56% vs. 71% disease-free at 20 years) but not cancer-related death.

Conclusions:

• Lymph node metastasis in T1 DTC is associated with vascular/soft tissue invasion, not tumor size.
• Positive lymph nodes indicate a higher risk of recurrence in T1 DTC patients.
• Lymph node metastasis does not significantly impact cancer-specific mortality in T1 DTC.