When it comes to papillary thyroid cancer (PTC), many patients are treated with radioactive iodine (RAI) ablation following removal of the thyroid gland (thyroidectomy) to kill any remaining thyroid cells. In a recent study, a team of researchers found that it can now identify lower-risk thyroid cancer patients who may not need that RAI treatment.

Paul Walfish, MD, and a team of researchers used stimulated thyroglobulin in combination with a neck ultrasound to assess each patient’s risk of cancer recurrence. From this study, they were able to identify lower risk patients who were not treated with RAI ablation. All of the patients tested showed no residual or recurrent disease at a mean prospective follow-up of 6.2 years.

Radiology Business spoke with Walfish to discuss his findings that were published in Endocrine—and the impact the data could have on the treatment of thyroid cancer for radiologists. 

Radiology Business: What prompted you to do research on this study? 
Paul Walfish, MD: Each year, an estimated 62,000 people are diagnosed with thyroid cancer. Many of them with primary papillary thyroid cancer (PTC) lesions greater than 1 cm are treated with a total or near total thyroidectomy. Following the procedure, clinicians take steps to identify and remove remaining normal or cancer cells—often using a treatment known as RAI therapy. The guidelines on the use of RAI have been somewhat broad, indicating that most post total thyroidectomy low and intermediate risk patients with lesions greater than 1 cm should receive a routine dose of RAI (32-100 mCi). Subsequent to this one dose of RAI, risk stratification classification for future residual or recurrent thyroid cancer have been devised on the basis of a follow up 131-i thyroid scan and serum thyroglobulin studies. However, it has not been well established whether most of these patients require even one dose of RAI.

The goal of our research was to determine whether the use of a prospective risk-assessment strategy prior to RAI could help to identify which low and intermediate risk PTC patients may not require RAI.

What were some of the findings when using stimulated thyroglobulin in combination with neck ultrasound on patients with cancer? 
In our study, we used serial post-operative stimulated thyroglobulin levels and results from neck ultrasound as a personalized risk stratification strategy for helping to identify which PTC patients at low- or intermediate risk have evidence of residual PTC. These low and intermediate risk patients were followed from 2006 to 20013. Among the 129 PTC patients who were classified as low/intermediate risk, results showed that 116 were able to avoid treatment with RAI with virtually no risk of recurrent disease at 6.2 years mean follow up. A subsequent 2 year follow up since publication to a mean of 8.2 years (personal observations) has identified no new PTC patients in this cohort with clinically significant residual thyroid cancer.

What are some of the impacts these findings could have on the treatment of thyroid cancer for radiologists? 
Based on these findings, clinicians may be better able to identify among low- and intermediate risk PTC patients those who can avoid treatment with RAI with little or no risk of recurrence. This may help to reduce the risk to patients of immediate RAI as well as avoid patient inconvenience, emotional stress and healthcare costs. In addition, the proposed new strategy could help more clinicians use more objective and reliable parameters to risk classify such PTC patients without the routine administration of RAI and avoid such treatment in the vast majority.  

Are you looking to do any future studies to follow up with the data you found? 
It is our hope that such a patient care strategy will continue to provide long-term data that will validate our current findings that a pre-RAI prospective risk assessment strategy after a total thyroidectomy in low- and intermediate-risk PTC could provide more objective and reliable guidelines for the improved selection of RAI administration to PTC patients. It is also our hope that in this way many such RAI therapies will be unnecessary.