Thyroid cancer cases in the U.S. are on the increase, with the higher incident rates due to PTC. However, the researchers state that although obesity is a recognized risk factor for various cancers, it remains unclear whether the higher risk of cancer is responsible for the increase or improved detection rates.
They say: "Our study shows that those patients with increasing BMI have a progressively increasing risk in presenting with late-stage PTC. This finding is especially seen in the obese and morbidly obese populations."
Avital Harari, M.D., and her team at LA's UCLA David Geffen School of Medicine reviewed 443 patients' medical records from an academic tertiary care center, with an average age of 48.2 years, who had a total thyroidectomy, i.e. surgery to remove most of the thyroid gland at an initial procedure for PTC or other forms of cancer from January 2004 through March 2011.
The team divided the participants into four categories based on the patients' body mass index (BMI), i.e. normal (18.5-24.9), overweight (25-29.9), obese (30-39.9) and morbidly obese (≥40).
The researchers state: "Greater BMI was associated with more advanced disease stage at presentation. Specifically, the obese and morbidly obese categories presented more as stage III or IV disease," noting that both the obese and morbidly obese groups also had a higher occurrence of PTC tall cell variant, "suggesting that these groups have a higher risk of more aggressive tumor types."
They conclude writing: "Given our findings, we believe that obese patients are at a higher risk of developing aggressive thyroid cancers and thus should be screened for thyroid cancer by sonography, which has been shown to be more sensitive in detecting thyroid cancer than physical examination alone."
Invited Critique: Thyroid Cancer Operations for Obese PatientsQuan-Yang Duh, M.D., from San Francisco's University of California writes in an invited comment:
"Harari and colleagues from UCLA (University of California, Los Angeles) showed us one more reason to be concerned about the current obesity epidemic - obese patients have more advanced thyroid cancer. 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. However, the authors found that higher body mass index is associated with a later stage of thyroid cancer."
He concludes saying:
"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."
Written By Petra Rattue