Monitoring response to neo-adjuvant chemotherapy with F-18 FDG PET/CT.

摘要

In recent issue of the Journal of Surgical Oncology, Choi et al. [1] evaluated the role of PET/CT to neo-adjuvant chemotherapy in advanced breast cancer compared with ultranosography (US) and magnetic resonance imaging (MRI). The authors concluded that MRI is better than PET/CT in monitoring the effect of neo-adjuvant chemotherapy in advanced breast cancer. For assessment of clinical response of US and MRI during neo-adjuvant chemotherapy, authors used Response Evaluation Criteria in Solid Tumors (RECIST) [2], which is one of the most widely applied criteria for tumor size measurement. Since PET/CT provides metabolic and functional information, which is not applicable to RECIST criteria, authors used EORTC (European Organization of Research and Treatment of Cancer) guidelines [3]. The authors wrote that they kept with the EORTC guidelines and denned >50% decline of peak standardized uptake value (pSUV) on FDG metabolism as complete response. However, according to the EORTC recommendations, complete metabolic response would be complete resolution of F-18 FDG uptake within the tumor volume so that it was indistinguishable from surrounding normal tissue [3]. There is no mentioning about 50% decline of pSUV in EORTC recommendations. Also, partial metabolic response is classified in EORTC recommendations as 15-25% reduction in SUV after one cycle of chemotherapy or more than 25% reduction after one treatment cycle, which was not used in this manuscript. For US and MRI, authors assessed of clinical response as complete response, partial response, and stable disease. On the other hand, for the PET/CT, authors assessed of clinical response only as responder and non-responder, which is discriminating against other modalities.