title: Immune-related response assessment during PD-1 inhibitor therapy in advanced non-small-cell lung cancer patients.
abstract: BACKGROUND
  Tumor response characteristics using immune-related RECIST1.1 (irRECIST1.1) in advanced non-small-cell lung cancer (NSCLC) patients treated with nivolumab monotherapy in the clinical setting have not been previously described with a direct comparison with the assessments according to the conventional RECIST1.1.
  
  
  METHODS
  Fifty-six advanced NSCLC patients treated with nivolumab monotherapy after its Food and Drug Administration (FDA) approval were retrospectively studied. Tumor burden was quantified on serial CT scans during therapy using irRECIST1.1, which uses unidimensional measurements and includes new lesion measurements in total tumor burden. Response assessments by irRECIST1.1 were compared with assessments by RECIST1.1. Responses of individual lesions in different organs were also compared.
  
  
  RESULTS
  Tumor burden change at best overall response ranged from -66.8 to +278.1% (median: +3.9%). Response rate was 14% (8/56; 8 partial responses, 0 complete responses) by irRECIST1.1 and by RECIST1.1. Time-to-progression (TTP) by irRECIST1.1 was longer than TTP by RECIST1.1 (median TTP: not reached vs. 1.9 months, respectively). No patients experienced pseudoprogression during the study. Among 128 target lesions, the lesion-based size change at best response differed significantly across different organs, with adrenal lesions and lymph nodes having greater size decrease, followed by lung, while liver and other miscellaneous lesions had lesser degree of size decrease (p= 0.002).
  
  
  CONCLUSIONS
  Immune-related response evaluations using irRECIST1.1 in advanced NSCLC patients treated with nivolumab resulted in the identical response rate and longer TTP compared to RECIST1.1. No pseudoprogression cases were observed during the study. Adrenal lesions and lymph nodes were more responsive and liver lesions were less responsive to nivolumab.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Nishino
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: Nikhil H
authors.initials: NH
authors.lastname: Ramaiya
authors.affiliation: Department of Medical Oncology and Department of Medicine Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: Emily S
authors.initials: ES
authors.lastname: Chambers
authors.affiliation: Department of Medical Oncology and Department of Medicine Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: Anika E
authors.initials: AE
authors.lastname: Adeni
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatabu
authors.affiliation: Department of Medical Oncology and Department of Medicine Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: Pasi A
authors.initials: PA
authors.lastname: Jänne
authors.affiliation: Department of Medical Oncology and Department of Medicine Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: F Stephen
authors.initials: FS
authors.lastname: Hodi
authors.affiliation: Department of Medical Oncology and Department of Medicine Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215 USA.
authors.forename: Mark M
authors.initials: MM
authors.lastname: Awad
keywords: Computed tomography; Immunotherapy; Non-small-cell lung cancer; PD-1 inhibitor; Tumor response evaluation