Indolent behavior of malignant Bethesda III nodules compared to Bethesda V/VI nodules.

BACKGROUND

The Bethesda System classifies all fine needle aspiration specimens into one of six categories. We speculated that cancers within each Bethesda category would have distinct clinical behavior.

METHODS

This is a retrospective analysis of patients from a single academic medical center with a histologic diagnosis of thyroid cancer who had an initial diagnosis of Bethesda III, IV, V, or VI cytology.

RESULTS

A total of 556 cases were included, with 87 cases of Bethesda III, 109 cases of IV, 120 cases of V, and 240 cases of VI. Bethesda III showed similarities with V/VI compared to IV with predominance of papillary thyroid cancer. The interval from diagnosis to surgery was longer in Bethesda III compared to Bethesda V/VI (median 78 vs. 41 days, p<0.001) (Figure 1). Yet, patients with Bethesda III had a higher probability of achieving remission (62 vs.46 %, p<0.03), a lower possibility of recurrence (8 vs. 24%, p<0.001) and a shorter interval to achieve remission (median 1218 vs.1682 days p = 0.02) compared to Bethesda V/VI which did not change after adjusting for age, gender, radioactive iodine therapy, mode of surgery and tumor size. More than 70% of Bethesda III that later presented with recurrence had T3/T4 disease or distant metastasis.

CONCLUSIONS

Cancers with Bethesda III cytology had a less aggressive clinical phenotype with better prognosis compared to V/VI despite histological similarities. The time to remission was shorter in Bethesda III despite a longer interval between diagnosis and surgery. The initial cytological diagnosis may guide management.

Informations de copyright

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