Obese Patients at Higher Risk of Aggressive Thyroid Tumors

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Obese patients present with more advanced and more aggressive forms of papillary thyroid cancer and should be screened for thyroid cancer with sonography, which is more sensitive in detecting thyroid cancer than physical examination alone, according to a study published online in the Archives of Surgery.

“Patients more likely to benefit from screening are those who are overweight, obese, or morbidly obese and those older than 45 years, who, by AJCC stage definition, have a higher risk of stage III or IV disease,” the researchers concluded. “Our recommendation mirrors a similar proposal for breast cancer screening, where studies have suggested that a more vigilant mammogram screening regimen should be instituted for obese patients,” they noted.

Researchers at the UCLA David Geffen School of Medicine reviewed the medical records of all patients older than 18 years who underwent total thyroidectomy as an initial procedure for papillary thyroid cancer or its variants from January 1, 2004, through March 31, 2011. A total of 443 patients were included in the final analysis. Patients were grouped according to body mass index: normal (18.5–24.9 kg/m2), overweight (25–29.9 kg/m2), obese (30–39.9 kg/m2), and morbidly obese (≥ 40 kg/m2).

The study showed that patients with increasing body mass index have a progressively increasing risk in initially presenting with late-stage papillary thyroid cancer. “This finding is especially seen in the obese and morbidly obese populations,” the researchers noted.

Specific Findings

Obese and morbidly obese patients presented more often with stage III or IV disease. The obese and morbidly obese groups also had higher prevalences of papillary thyroid cancer tall cell variant, a more aggressive tumor type. The researchers also found that increasing body mass index significantly predicted increased length of hospital stay and anesthesia induction times.

Other studies have shown an increased incidence of thyroid cancer among obese populations, the authors noted, adding that their study “is novel in that it assesses the risk of presenting with both aggressive and disseminated disease. In addition, this study was performed in a multiethnic population with a large sample size,” they pointed out.

“This parallel increase in the rates of obesity and thyroid cancer is intriguing, but without a much larger population study, we cannot determine whether obesity causes thyroid cancer,” according to an invited critique by Quan-Yang Duh, MD, of the University of California, San Francisco. “What is somewhat surprising is the lack of increase in surgical complications in obese patients,” he stated.

“For obese patients with papillary thyroid cancer, the bad news is that the cancer is likely to be more advanced. The good news is that thyroid operation remains safe even in obese patients with advanced disease,” Dr. Duh concluded.

Harari A, et al: Arch Surg. May 21, 2012 (early release online).

Duh Q-Y: Arch Surg. May 21, 2012 (early release online)