OVERUSE OF RAI IN THYROID CANCER

The use of radioactive iodine (RAI) for the treatment of thyroid cancer has decreased in recent years, but up to one-quarter of patients might still receive it unnecessarily, according to a study published online February 16 in JAMA Internal Medicine.

"Given that thyroid cancer incidence has increased more than 250% over the last 2 decades, with the greatest proportion of new cases identified as papillary thyroid microcarcinomas [PTMCs], our study highlights the fact that a significant proportion of this patient population may be receiving inappropriate RAI," said Sanziana Roman, MD, FACS, professor of surgery at the Duke University School of Medicine in Durham, North Carolina.

The use of RAI in thyroid cancer is controversial. Adjuvant RAI is commonly used in the treatment of differentiated thyroid cancer, according to Dr Roman, to ablate remaining thyroid tissue, decrease the risk for recurrence, and treat residual disease.

However, some experts have questioned whether RAI is always necessary after surgery. Some have even suggested that RAI is overtreatment, with no evidence of benefit in low-risk thyroid cancer.

Current guidelines do not recommend adjuvant RAI for patients with medullary thyroid cancer, anaplastic thyroid cancer, or PTMC, Dr Roman explained.

RAI therapy can be expensive and is associated with many complications, including radiation-induced malignancies. Because thyroid cancer affects young adults, these effects can persist throughout life.

Dr Roman and colleagues used the National Cancer Data Base to identify patients with anaplastic thyroid cancer, medullary thyroid cancer, and PTMC diagnosed from 1998 to 2011. They used the Surveillance, Epidemiology, and End Results (SEER) database for crossvalidation, and estimated the cost of PTMC from Medicare reimbursement data.

Patients with PTMC were included if their tumors were 1 cm or smaller, their histology was nonaggressive, they had no regional or distant metastases, and they had clear margins. In addition, the tumor could not extend beyond the thyroid.

RAI was inappropriately used in 1.6% of the 3095 patients with anaplastic thyroid cancer, 3.4% of the 6375 patients with medullary thyroid cancer, and 23.3% of the 60,586 patients with PTMC.

Average cost per patient ranged from $5429 to $9105.

Factors associated with inappropriate RAI treatment, on adjusted analyses, were Hispanic origin, low income, nonacademic treatment settings, tumor multifocality, and larger tumor size.

Patients with PTMC who received RAI were more likely to be younger, receive treatment at a nonacademic medical center, and have multifocal and larger tumors (P < .001 for all).

In fact, PTMC patients "treated at nonacademic centers were nearly twice as likely to receive inappropriate RAI as those treated at academic centers," Dr Roman reported.

A time-trend analysis showed that the rate of inappropriate RAI administration did not change over time in community programs, but decreased in academic programs, she noted.

"This finding suggests that practice patterns in nonacademic or community centers are slower to change, even in the face of emerging data and updated national guidelines," she said.

"Our findings suggest that patients from certain subsets of vulnerable populations may have less access to healthcare providers or facilities that are more likely to practice updated care," Dr Roman explained.

"This study highlights the importance of better dissemination of national practice guidelines among all healthcare providers and centers, especially in areas that serve vulnerable populations," she emphasized.

"This study is important because it identifies subgroups at risk for unnecessary radioactive iodine treatment. This study and others have demonstrated variation in thyroid cancer care, with a pattern of more intensive care than what the current clinical guidelines recommend," said Megan Haymart, MD, assistant professor of medicine at the University of Michigan in Ann Arbor.

In a previous study, Dr Haymart and her colleagues found a significant increase in the use of RAI, as well as a wide variation in its use, suggesting the need for clearer guidelines.

Certain high-risk patients with well-differentiated thyroid cancer could have a survival benefit with RAI, Dr Haymart told Medscape Medical News.

"Although RAI should never be given to a patient with medullary thyroid cancer, there is a continuum in regard to benefit in well-differentiated thyroid cancer patients," she explained. "Our most recent literature and clinical guidelines do not support the use of radioactive iodine in patients with low-risk PTMC."

"Patient and physician education is needed to improve the tailored treatment of thyroid cancer. This includes less radioactive iodine treatment for our patients with low-risk PTMC and no radioactive iodine treatment for our patients with medullary and anaplastic thyroid cancer," she said.

Dr Roman has disclosed no relevant financial relationships. Dr Haymart reports receiving grant funding from the National Institutes of Health.

JAMA Intern Med. Published online February 16, 2015. Abstract