SPECT/CT Helps Staging and Risk Stratification of Thyroid Cancer

May 8, 2012

SPECT/CT, commonly used for imaging thyroid cancer after radioiodine therapy, was used before therapy to better identify and characterize the cancer.

Single positron emission computed tomography (SPECT/CT) improves staging and risk stratification of thyroid cancer and has an impact on long-term follow-up treatment strategies, according to results from a study published in the May issue of The Journal of Nuclear Medicine.

SPECT/CT has been commonly used for imaging thyroid cancer after radioiodine therapy. More recently, however, it has been used before initiation of radioiodine therapy to better identify and characterize focal activity seen on planar scans for differentiating between metastatic lesions and benign uptake in residual thyroid tissue or normal organs.

Anca M. Avram, MD, the study’s author, assessed SPECT/CT use in staging and decisions regarding if I-131 therapy should be initiated. “The new technology of SPECT/CT has substantially improved the interpretation of planar studies and can be implemented in the post-operative management protocols of thyroid cancer patients,” she said.

The author wrote that SPECT/CT changed post-surgical staging in 21 percent of patients who were assessed and modified the treatment approach in 36 percent of the study patients who had thyroid cancer. Findings also showed that the testing led to avoidance of unnecessary I-131 therapy in 20 percent of patients who did not have the disease. In addition, findings of the the pre-ablation scans caused treating physicians to change the recommended I-131 therapy in 58 percent if the patients, as compared to therapy based on histopathologic risk stratification alone. 

SPECT/CT is also very useful for evaluating unusual radioactivity distributions in thyroid cancer patients; accurate anatomic localization of radioactivity foci permits rapid exclusion of physiologic mimics of disease, or confirmation of metastatic lesions to unexpected sites.

“Diagnostic radioiodine scintigraphy with SPECT/CT provides a clear advantage for the management of patients with thyroid cancer,” said Avram. “By integrating clinical, pathology and imaging information, the nuclear medicine physicians are able to offer an individualized treatment plan, bringing the nuclear medicine community a step closer to the goal of personalized medicine.”