Breast-specific gamma imaging could help predict pathologic response to chemotherapy

Breast-specific gamma imaging (BSGI) performed with comparable sensitives in detecting residual tumor compared to breast MRI, and may be a more useful tool for predicting a complete pathologic response to neoadjuvant chemotherapy (NAC) in those with breast cancer, according to research published online Jan. 8 in the American Journal of Roentgenology.  

BGSI is a relatively new nuclear medicine imaging tool that can be used as a complementary modality for initial breast cancer diagnosis, according to Shannon Kim, MD, radiologist at Eastern Virginia Medical School, and colleagues. The authors noted, however, that few studies have compared the accuracy of BSGI and breast MRI for such clinical situations.  

To assess the diagnostic performance of BSGI and breast MRI in assessing for residual tumor after NAC in patients with breast cancer, a total of 114 patients (average age 52 years) underwent BSGI and breast MRI after undergoing NAC.  

Of these patients, 112 then underwent breast surgery. Additionally, thirty of the 114 patients had a had a complete pathologic response to NAC.   

The researchers found BSGI and breast MRI had comparable sensitivities in accurately detecting residual tumors after NAC (70 percent vs. 83 percent). However, BSGI had a higher specificity than MRI in accurately determining complete response after NAC (90 percent vs. 60 percent).    

“These results suggest that BSGI may be a useful adjunct imaging modality for the pre- diction of a complete treatment response after undergoing NAC treatment,” Kim et al. wrote. “In clinical practice, the lower specificity of MRI would lead to more biopsies, which can increase cost to patients in time, money and anxiety.”