Endocrine Abstracts

Introduction: Papillary thyroid microcarcinoma (PTMC) is defined as a papillary thyroid cancer measuring 10 mm or less in greatest dimension. Diagnosis of PTMC could be established during the surgery for benign thyroid lesions and after fine needle aspiration biopsy. Despite the small size, PTMC could be highly aggressive tumor showing metastases and elevated invasiveness. However, correlation between tumor size and risk of lymph-node metastases remains unclear.

The aim of the study was to investigate and correlate local lymph-node metastases and multifocality as factors of tumor aggressiveness in patients with different sizes of PTMC.

Materials and methods: 1408 patients operated on for PTMC during 1986-2009 in Kyiv City Teaching Endocrinological Center were identified for study. Three groups were established according to size of primary tumor. There were patients with size of PTMC less than 3 mm in maximum diameter in group 1 (n=197), 3–5 mm in group 2 (n=297), and 5–10 mm in group 3 (n=914) respectively. Such clinico-pathological features as local lymph-node metastases and multifocality were compared between groups.

Results: The statistically significant frequency of local lymph-node metastases was higher in group 3 (9.0%) compared to group 2 (3.0%) and group 1 (0%), P<0.01. Multifocality was higher in group 3 (24.5%) and group 2 (21.5%) compared to group 1 (10.7%), P<0.01. There was no statistical significant difference for multifocality in group 3 compared to group 2.

Conclusions: Our finding suggest that patients with size of PTMC between 5 to 10 mm (group 3) may have a higher risk of lymph-node metastases compared to those who have smaller sizes of PTMC. Long-time follow-up study is ongoing in order to determine consequences for patients’ outcome.