Ai Kameyama1, Juanjuan Ye1, Ayaka Shimomura2, Masanao Yokohira1, Yuko Nakano-Narusawa1, Keiko Yamakawa1, Yuri Mukai1, Takayuki Sanomura3, Hiroyuki Okuyama4, Nobuyuki Miyatake5, Mutsuo Furihata6, Chiharu Tanaka6, Riko Kitazawa7, Yoshimi Bando8, Yamato Suemitsu9, Motohiro Kojima10, Mari Mino-Kenudson11, Yasuyuki Suzuki2, Keiichi Okano2, Yoko Matsuda12. 1. Oncology Pathology, Faculty of Medicine, Kagawa University, Japan. 2. Department of Gastroenterological Surgery, Faculty of Medicine, Kagawa University, Japan. 3. Department of Radiology, Faculty of Medicine, Kagawa University, Japan. 4. Department of Clinical Oncology, Faculty of Medicine, Kagawa University, Japan. 5. Department of Hygiene, Faculty of Medicine, Kagawa University, Japan. 6. Department of Pathology II, Kochi University, Japan. 7. Division of Diagnostic Pathology, Ehime University Hospital, Japan. 8. Division of Pathology, Tokushima University Hospital, Japan. 9. Department of Pathology, Japanese Red Cross Medical Center, Japan. 10. Division of Pathology, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Japan. 11. Department of Pathology, Massachusetts General Hospital and Harvard Medical School, USA. 12. Oncology Pathology, Faculty of Medicine, Kagawa University, Japan. Electronic address: matsuda.yoko@kagawa-u.ac.jp.
Abstract
BACKGROUND: The pathologic assessments of tumor response after neoadjuvant chemoradiotherapy (NACRT) are critical to improving the prognostic stratification for patients with pancreatic ductal adenocarcinoma (PDAC). Here we clarified the utility of our new grading system based on the area of residual tumor (ART) as compared to existing systems, such as the College of American Pathologists (CAP) and MD Anderson (MDA) score. METHODS: Eight reviewers individually evaluated the tumor regression grade of 30 patients with PDAC based on three types of grading systems. The interobserver concordance and clinicopathological characteristics were compared between the three systems. RESULTS: The interobserver concordance (kappa value) of the ART, CAP, and MDA score were 0.61, 0.48, and 0.53, respectively. Discrepant cases, which were 27% of the cases, exhibited smaller tumor and tumor bed sizes than concordant cases. The reduction in tumor size evaluated by microscopy showed a correlation with the rate of change in carcinoembryonic antigen (CEA) level, CA19-9 level, and tumor size on computed tomography (CT). The ART score was correlated with the tumor size on CT before and after NACRT and disease-free survival. The CAP and MDA scores were not associated with prognosis. CONCLUSION: The ART grading system may be the most practical system to assess the tumor response in post-NACRT resections of PDAC.
BACKGROUND: The pathologic assessments of tumor response after neoadjuvant chemoradiotherapy (NACRT) are critical to improving the prognostic stratification for patients with pancreatic ductal adenocarcinoma (PDAC). Here we clarified the utility of our new grading system based on the area of residual tumor (ART) as compared to existing systems, such as the College of American Pathologists (CAP) and MD Anderson (MDA) score. METHODS: Eight reviewers individually evaluated the tumor regression grade of 30 patients with PDAC based on three types of grading systems. The interobserver concordance and clinicopathological characteristics were compared between the three systems. RESULTS: The interobserver concordance (kappa value) of the ART, CAP, and MDA score were 0.61, 0.48, and 0.53, respectively. Discrepant cases, which were 27% of the cases, exhibited smaller tumor and tumor bed sizes than concordant cases. The reduction in tumor size evaluated by microscopy showed a correlation with the rate of change in carcinoembryonic antigen (CEA) level, CA19-9 level, and tumor size on computed tomography (CT). The ART score was correlated with the tumor size on CT before and after NACRT and disease-free survival. The CAP and MDA scores were not associated with prognosis. CONCLUSION: The ART grading system may be the most practical system to assess the tumor response in post-NACRT resections of PDAC.