title: Global Pattern of Nasopharyngeal Cancer: Correlation of Outcome With Access to Radiation Therapy.
abstract: OBJECTIVE
  This study aimed to estimate the treatment outcome of nasopharyngeal cancer (NPC) across the world and its correlation with access to radiation therapy (RT).
  
  
  METHODS
  The age-standardized mortality (ASM) and age-standardized incidence (ASI) rates of NPC from GLOBOCAN (2012) were summarized, and [1-(ASM/ASI)] was computed to give the proxy relative survival (RS). Data from the International Atomic Energy Agency (IAEA) and the World Bank were used to assess the availability of RT in surrogate terms: the number of RT equipment units and radiation oncologists per million population.
  
  
  RESULTS
  A total of 112 countries with complete valid data were analyzed, and the proxy RS varied widely from 0% to 83% (median, 50%). Countries were categorized into Good, Median, and Poor outcome groups on the basis of their proxy RS (<45%, 45%-55%, and >55%). Eighty percent of new cases occurred in the Poor outcome group. Univariable linear regression showed a significant correlation between outcome and the availability of RT: proxy RS increased at 3.4% (P<.001) and 1.5% (P=.001) per unit increase in RT equipment and oncologist per million population, respectively. The median number of RT equipment units per million population increased significantly from 0.5 in the Poor, to 1.5 in the Median, to 4.6 in the Good outcome groups, and the corresponding number of oncologists increased from 1.1 to 3.3 to 7.1 (P<.001).
  
  
  CONCLUSIONS
  Nasopharyngeal cancer is a highly treatable disease, but the outcome varies widely across the world. The current study shows a significant correlation between survival and access to RT based on available surrogate indicators. However, the possible reasons for poor outcome are likely to be multifactorial and complex. Concerted international efforts are needed not only to address the fundamental requirement for adequate RT access but also to obtain more comprehensive and accurate data for research to improve cancer outcome.
authors.affiliation: Clinical Oncology Center, University of Hong Kong-Shenzhen Hospital, Shenzhen, China.
authors.forename: Ka-On
authors.initials: KO
authors.lastname: Lam
authors.affiliation: Clinical Oncology Center, University of Hong Kong-Shenzhen Hospital, Shenzhen, China. Electronic address: annelee@hku-szh.org.
authors.forename: Anne W M
authors.initials: AW
authors.lastname: Lee
authors.affiliation: Department of Systems Engineering and Engineering Management, City University of Hong Kong, Hong Kong, China.
authors.forename: Cheuk-Wai
authors.initials: CW
authors.lastname: Choi
authors.affiliation: Clinical Oncology Center, University of Hong Kong-Shenzhen Hospital, Shenzhen, China.
authors.forename: Henry C K
authors.initials: HC
authors.lastname: Sze
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Zietman
authors.affiliation: International Atomic Energy Agency, Vienna, Austria.
authors.forename: Kirsten I
authors.initials: KI
authors.lastname: Hopkins
authors.affiliation: International Atomic Energy Agency, Vienna, Austria.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Rosenblatt
mesh_terms: D000367:Age Factors; D002173:Cancer Care Facilities / Q000600:supply & distribution*; D019049:Developed Countries / Q000706:statistics & numerical data; D003906:Developing Countries / Q000706:statistics & numerical data; D014943:Global Health / Q000706:statistics & numerical data*; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D006801:Humans; D007390:International Agencies / Q000706:statistics & numerical data; D016014:Linear Models; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000532:radiotherapy*; D018787:Radiation Oncology; D016896:Treatment Outcome; D000078329:Workforce