Patients whose thyroid cancer is incidentally discovered on imaging performed for reasons other than evaluation of the thyroid gland tend to be older, male and have a higher stage of the disease at diagnosis, but there did not appear to be differences in tumor characteristics such as size and metastases compared with patients whose cancer was found after targeted thyroid evaluation, according to a study published Online First by JAMA Otolaryngology–Head & Neck Surgery.
The incidence of thyroid cancer has increased over the past 30 years, but the reason behind the increase remains unclear. Some researchers have suggested the increase is due to improvements in imaging and diagnostic techniques, while others have argued the increase represents a true rise in incidence, according to the study background.
Frederick Yoo, M.D., and colleagues at Penn State College of Medicine/Penn State Milton S. Hershey Medical Center, Hershey, Pa., sought to compare the clinical and pathologic characteristics of incidentally (ID) and nonincidentally discovered (NID) thyroid cancer to assess whether the rise in incidence is related to disease detection or actually reflects an increased disease.
The study included 31 patients with ID thyroid cancer (average age 56 years at diagnosis) and 207 patients (average age nearly 42 years at diagnosis) with NID thyroid cancer. The ID group was 54.8 percent male compared with 13.5 percent male in the NID group.
Study findings indicate that the ID group had higher stage of the disease at diagnosis but no difference between the two groups was found for tumor size, local invasion, lymph node involvement or distant metastases.
“These findings imply that improved detection may not represent the only cause of the increased incidence of thyroid cancer,” the study concludes.
(JAMA Otolaryngol Head Neck Surg. Published online October 10, 2013. doi:10.1001/jamaoto.2013.5050.