Cancer Res Treat.  2019 Jan;51(1):12-23. 10.4143/crt.2017.273.

The Effect of Hospital Case Volume on Clinical Outcomes in Patients with Nasopharyngeal Carcinoma: A Multi-institutional Retrospective Analysis (KROG-1106)

  • 1Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
  • 2Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea.
  • 3Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
  • 4Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
  • 5Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
  • 6Department of Radiation Oncology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
  • 7Department of Radiation Oncology, Pusan National University Hospital, Busan, Korea.
  • 8Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea.
  • 9Department of Radiation Oncology, School of Medicine, Kyungpook National University, Daegu, Korea.
  • 10Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
  • 11Department of Radiation Oncology, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
  • 12Department of Radiation Oncology, Chungnam National University School of Medicine, Daejeon, Korea.
  • 13Department of Radiation Oncology, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea.
  • 14Department of Radiation Oncology, Chung-Ang University Hospital, Seoul, Korea.


The purpose of this study was to investigate the effect of hospital case volume on clinical outcomes in patients with nasopharyngeal carcinoma (NPC).
Data on 1,073 patients with cT1-4N0-3M0 NPC were collected from a multi-institutional retrospective database (KROG 11-06). All patients received definitive radiotherapy (RT) either with three-dimensional-conformal RT (3D-CRT) (n=576) or intensity-modulated RT (IMRT) (n=497). The patients were divided into two groups treated at high volume institution (HVI) (n=750) and low volume institution (LVI) (n=323), defined as patient volume ≥ 10 (median, 13; range, 10 to 18) and < 10 patients per year (median, 3; range, 2 to 6), respectively. Endpoints were overall survival (OS) and loco-regional progression-free survival (LRPFS).
At a median follow-up of 56.7 months, the outcomes were significantly better in those treated at HVI than at LVI. For the 614 patients of propensity score-matched cohort, 5-year OS and LRPFS were consistently higher in the HVI group than in the LVI group (OS: 78.4% vs. 62.7%, p < 0.001; LRPFS: 86.2% vs. 65.8%, p < 0.001, respectively). According to RT modality, significant difference in 5-year OS was observed in patients receiving 3D-CRT (78.7% for HVI vs. 58.9% for LVI, p < 0.001) and not in those receiving IMRT (77.3% for HVI vs. 75.5% for LVI, p=0.170).
A significant relationship was observed between HVI and LVI for the clinical outcomes of patients with NPC. However, the difference in outcome becomes insignificant in the IMRT era, probably due to the standardization of practice by education.


Nasopharyngeal neoplasms; Hospital; Low- or high-volume; Treatment outcome; Three-dimensional conformal radiotherapy; Intensity-modulated radiotherapy

MeSH Terms

Cohort Studies
Disease-Free Survival
Follow-Up Studies
Nasopharyngeal Neoplasms
Radiotherapy, Intensity-Modulated
Retrospective Studies*
Treatment Outcome
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