Comparison of the diagnostic performance of response evaluation criteria in solid tumor 1.0 with response evaluation criteria in solid tumor 1.1 on MRI in advanced breast cancer response evaluation to neoadjuvant chemotherapy.

Objective: To compare the diagnostic performance in evaluating the response of neoadjuvant chemotherapy (NAC), between the response evaluation criteria in solid tumor (RECIST) 1.0 and RECIST 1.1, on magnetic resonance imaging (MRI) for advance breast cancer patients. Materials and Methods: Breast cancer patients, who underwent NAC between 2005 and 2010, were included. Both pre-chemotherapy and post-chemotherapy MRIs were performed within 1-4 weeks before and after NAC. Only the patients with subsequent surgery were included. The response to NAC was assessed by using RECIST 1.0 and RECIST 1.1. Patients with a complete or partial response on MRI were considered as responders, and those with stable or progressive disease were considered as non-responders. Tumor necrosis > 50% on pathology was defined as responders and necrosis <50% was defined as non-responders. The diagnostic accuracy of both RECIST 1.0 and RECIST 1.1 was analyzed and compared by receiver operating characteristic curve analysis. Results: Seventy-nine females (mean age 51.0 +/- 9.3 years) were included. Pathology showed 45 responders and 34 non-responders. There were 49 responders and 30 non-responders on RECIST 1.0, and in 55 patients, RECIST 1.0 results agreed with pathologic results (69.6%). RECIST 1.1 showed 52 responders and 27 non-responders. In 60 patients, RECIST 1.1 results were in accordance with pathology results (75.9%). The area under the ROC curve was 0.809 for RECIST 1.0 and 0.853 for RECIST 1.1. Conclusion: RECIST 1.1 showed better diagnostic performance than RECIST 1.0, although there was no statistically significant difference between the two.