Diagnostic evaluation of clinical and radiological findingsafter neoadjuvant chemotherapy in breast cancer

Aim: The aim of this study is to compare the efficacy of PET/CT and contrast- enhanced breast MRI in the evaluation of neoadjuvant chemotherapy response in patients with malignant masses diagnosed by breast biopsy. Material and Method: As of February 2017, patients diagnosed with breast cancer using tru-cut needle or automated cuttingbiopsy gunin the General Surgery Department of the Zonguldak Bülent Ecevit University Medical Faculty Hospital were retrospectively screened. The study included 48 patients who underwent axillary lymph node dissection, mastectomy and received neoadjuvant chemotherapy. Weperformed breast MRI, diffusion-weighted MRI and whole-body PET/CT images after chemotherapy. We noted all demographic and histopathological parameters. The presence of tumor and lymph node metastasis in the histopathological reports of the patients was accepted as the gold standard, whereas thepresence of tumor and lymph node in imaging methods (MRI and PET/CT) was accepted as positive.The latter was compared with the pathological results. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of imaging methods in predicting neoadjuvant chemotherapy response were calculated. Results: The mean age of the patients was 51.08±12.21 years. Residual tumor was found in pathological specimens in 85.4% of the patients whereas lymph node involvement was in 50.0%. In 35.4% of the patients, lymph node involvement was detected on MRI. The number of patients whose tumors were seenon MRI (intermediate, rapid arterial phase enhancement and type 2/3 enhancement curve) was 31 (64.6%). The number of patients whose lymph node involvements were seen on MRI was 17 (35.4%), whereas the number of patients whose lymph node involvements on PET/CT was 22 (45.8%). In predicting the presence of tumor, the sensitivity, specificity, positive and negative predictive value and accuracy of MRI, vi evaluated according to early arterial phase enhancement (intermediate, rapid arterial) and late arterial (type 2/3 enhancement curve) was calculated as 65.8%, 42.8%, 87,1%, 17,6%, and 62,5%, respectively. On PET/CT, these were 46.3%, 57.1%, 86.3%, 15.3%, and 47.9%, respectively. The sensitivity, specificity, positive and negative predictive value and accuracy of MRI in predicting lymph node involvement were 54.1%, 83.3%, 76.4%, 64.5%, and 68.7%, respectively, whereas these were 29.1%, 95.8%, 87.5%, 57.5%, and 62.5%, respectively on PET/CT. Conclusion: In the evaluation of neoadjuvant chemotherapy response, MRI was found to have a higher sensitivity and PET/CT a higher specificity in tumor.Likewise, MRI was found to have a higher sensitivity and PET/CT a higher specificityin lymph node involvement. Only taken after neoadjuvant chemotherapy, we recommend use together of both MRI and PET/CT for this evaluation. Key Words: Breast cancer, neoadjuvant chemotherapy, MRI, PET/CT, residual tumor, lymph node involvement