Should small papillary thyroid cancer be observed? A population-based study.

BACKGROUND

Some centers have advocated selecting patients with small papillary thyroid cancer (PTC) to undergo active surveillance without surgical treatment. The objectives of the current study were to analyze thyroid cancer (TC)-related mortality in a population-based cohort and to determine the impact of small PTCs (defined as tumors ≤ 2 cm in greatest dimension) on TC-related mortality.

METHODS

Data on patients with TC of follicular cell origin from the National Cancer Institute's Surveillance, Epidemiology, and End Results 17 Registries database (1988-2007) were used to analyze the characteristics of PTCs ≤ 2 cm in patients who died from TC-related causes. The effects of clinical features on disease-specific survival were analyzed.

RESULTS

Over the 20-year study period, the rate of TC-related mortality was 2.8% (n = 1753 of 61,523 patients). Of the patients who died from TC-related causes, 38% had PTC, 10% had follicular TC, and 31.3% had anaplastic TC. PTCs ≤ 2 cm accounted for 12.3% of TC-related mortalities. Compared with patients who did not experience TC-related mortality from PTCs ≤ 2 cm, there were significantly higher rates of men (30% vs 17%; P < .01), patients aged ≥ 45 years (92% vs 52%; P < .01), tumors measuring >1 cm (59% vs 46%; P < .01), extrathyroid extension (41% vs 11%; P < .01), lymph node metastases (77% vs 28%; P < .01), and distant metastases (31% vs 1%; P < .01) among the patients who died from PTCs ≤ 2 cm. Independent risk factors for death from PTCs ≤ 2 cm included age ≥ 45 years, lymph node and distant metastases, extrathyroid extension, and undergoing less than thyroid lobectomy.

CONCLUSIONS

Because 12.3% of patients who experienced TC-related deaths had PTCs ≤ 2 cm despite undergoing thyroidectomy, the current results indicate that nonoperative management for patients who have PTCs ≤ 2 cm should be used with caution. Patients aged ≥ 45 years with PTCs ≤ 2 cm should undergo thyroidectomy.