title: The Role of Plasma Chromogranin A as Assessment of Treatment Response in Non-functioning Gastroenteropancreatic Neuroendocrine Tumors.
abstract: OBJECTIVE
  Chromogranin A (CgA) has been considered to be valuable not only in the diagnosis but also in monitoring the disease response to treatment. However, only a few studies have been published on this issue. We purposed to evaluate whether biochemical response using plasma CgA level is reliable in concordance with the clinical response of grade 1-3 nonfunctiong gastroenteropancreatic neuroendocrine tumors (GEP-NETs).
  
  
  METHODS
  Between March 2011 and September 2013, a total of 27 cases in 18 patients were analysed, clinically and radiologically while serial CgA tests were also conducted during treatment. Tumor responses were defined by both Response Evaluation Criteria in Solid Tumors (RECIST) criteria ver. 1.1 and biochemical criteria based on the CgA level.
  
  
  RESULTS
  Among the 27 cases analysed, no difference in the basal CgA level was observed with regard to gender, primary tumor site, tumor grade (World Health Organization classification), liver metastasis, number of metastatic site, and line of chemotherapy. The overall response rate (RR) by RECIST criteria ver. 1.1 was six out of the 27 cases (22.2%) and eight out of the 27 cases (29.6%) for biochemical RR. The overall concordance rates of the response based on RECIST and biochemical criteria were 74%. In grades 1 and 2 GEP-NETs (n=17), the concordance rate of the disease control was 94.1%. There was a significant difference for progression-free survival (PFS) between responders and non-responder in accordance to biochemical criteria (35.73 months vs. 5.93 months, p=0.05).
  
  
  CONCLUSIONS
  This study revealed that changes of the plasma CgA levels were associated with tumour response. Additionally, biochemical response based on serial CgA may be a predictive marker for PFS in GEP-NETs.
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Moonjin
authors.initials: M
authors.lastname: Kim
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Gastrointestinal Cancer Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sujin
authors.initials: S
authors.lastname: Lee
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Gastrointestinal Cancer Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jeeyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Gastrointestinal Cancer Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Park
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Gastrointestinal Cancer Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Joon Oh
authors.initials: JO
authors.lastname: Park
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Gastrointestinal Cancer Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Park
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Gastrointestinal Cancer Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Won Ki
authors.initials: WK
authors.lastname: Kang
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea ; Gastrointestinal Cancer Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Seung Tae
authors.initials: ST
authors.lastname: Kim
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood; D053379:Chromogranin A / Q000097:blood*; D005770:Gastrointestinal Neoplasms / Q000097:blood / Q000628:therapy; D006801:Humans; D018358:Neuroendocrine Tumors / Q000097:blood / Q000628:therapy; D010190:Pancreatic Neoplasms / Q000097:blood / Q000628:therapy
chemical_list: D014408:Biomarkers, Tumor; D053379:Chromogranin A
keywords: Chromogranin A; Gastro-enteropancreatic neuroendocrine tumor; Predictive