LAKE BUENA VISTA, FLA. – Obesity was strongly associated with more aggressive papillary thyroid carcinoma features, but not with a greater likelihood of disease recurrence in a review of nearly 7,300 patients.
Of the 7,284 consecutive surgery patients included in the study, 5,283 had normal weight (body mass index less than 25 kg/m2), 1,731 were overweight (BMI of 25 to less than 30 kg/m2), and 270 were obese (BMI of 30 kg/m2 or greater). The obese patients were significantly more likely than the normal-weight and overweight patients to have a number of features associated with more aggressive disease, Dr. Eun Jeong Ban of Yonsei University Health System in Seoul, South Korea, reported at the International Thyroid Congress.
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For example, tumors of 1 cm or greater were present in 43% of obese patients, compared with 31% of normal-weight patients and 34% of overweight patients. Multiple tumors were present in 15% of obese patients, compared with 11% of normal-weight patients and 10% of overweight patients, and bilateral tumors were present in 31% of obese patients, compared with 20% of normal-weight patients and 25% of overweight patients, Dr. Ban said.
Further, stage T3 disease was present in 62%, 51%, and 55% of obese, normal-weight and overweight patients, respectively; stage T4a disease was present in 4.4%, 1.7%, and 2.5% of the patients in the groups, respectively; stage T4b disease was present in 0.4%, 0%, and 0.1% of patients; and TNM stage IVa disease was present in 10%, 4.5%, and 7.3% of patients.
The groups did not differ with respect to regional lymph node stage or distant metastases.
They also did not differ with respect to recurrence rates, which were 1.5% in the obese patients and 1.6% and 1.7% in the normal-weight and overweight patients, respectively.
BMI was not found on multivariate analysis to predict risk for recurrence (odds ratios, 0.908 and 0.677 for BMI of 25-29 kg/m2 and BMI of 30 or greater, respectively). Only tumor multiplicity (OR, 2.463) and stage N1a (OR, 3.421) and N1b disease (OR, 4.246) were found to predict recurrence.
Although epidemiologic studies have suggested that obesity increases the risk of thyroid cancer, the association between BMI and the aggressiveness of papillary thyroid carcinoma remained unclear. These findings suggest that obesity also may increase the likelihood of a more aggressive disease course, Dr. Ban said at the meeting held by the American Thyroid Association, Asia-Oceania Thyroid Association, European Thyroid Association, and Latin American Thyroid Society.
Dr. Ban reported having no disclosures.