NEW YORK (Reuters Health) – Obese patients are more likely than others to present with advanced stage and more aggressive forms of papillary thyroid cancer.
“We are suggesting that obese patients over the age of 45 be screened sonographically for thyroid cancer,” Dr. Avital Harari from the UCLA David Geffen School of Medicine in Los Angeles told Reuters Health by email. “If their cancers can be caught earlier, the assumption is that mortality can be decreased.”
Although increased body mass index (BMI) has been linked to a more severe presentation and a higher risk of death from other types of cancer, such an association has never before been shown with papillary thyroid cancer.
Dr. Harari and colleagues conducted a retrospective study of 443 patients who underwent total thyroidectomy between 2004 and 2011. They reported online May 21st in Archives of Surgery that greater BMI was significantly associated with more advanced stage at presentation, with obese and morbidly obese patients presenting more often with stage III or IV disease.
Obese and morbidly obese patients were also significantly more likely than normal and overweight patients to present with the more aggressive tall cell variant subtype of papillary thyroid cancer, and increasing BMI tended to be associated with greater tumor size.
Total surgical complication rates did not differ with BMI group, but obese patients had significantly more postoperative recurrent laryngeal nerve dysfunction.
In addition, increasing BMI was associated with increased length of hospital stay and a trend toward longer total surgical times.
In subgroup analyses, morbid obesity remained significantly associated with later-stage disease among patients older than 45 years (who by American Joint Committee on Cancer stage definition already have a higher risk of stage III or IV disease).
Dr. Harari suggests two reasons why obese patients have higher rates of late stage and more aggressive thyroid cancer.
“One reason is that obese patients typically have a delay to diagnosis in relation to most illnesses,” he said. “In this case, it’s likely that their cancers and nodules are not felt on physical exam due to larger neck sizes. However, I also believe that the state of obesity itself, biologically, contributes to an increase in aggressive cancers.”
To investigate these hypotheses further, his group will be conducting additional studies, he said.
“It is important to be aware of the increased risk for these individuals not only for thyroid cancers but for all other types as well,” Dr. Harari advises. “The difference with thyroid cancer is that there is no current recommendation for screening as there is with breast and colon cancers. I suggest that there should be for those at higher risk for thyroid cancer, such as obese patients.”
Arch Surg 2012.