A preliminary outcome analysis of the patterns of care study in Japan for esophageal cancer patients with special reference to age: non surgery group

Abstract

Background: The Patterns of Care Study (PCS) was imported to Japan from the United States in July 1996. A preliminary outcome analysis of the PCS for esophageal cancer patients in Japan was made with special reference to age, because the elderly population is rapidly increasing in Japan. Patients and Methods: From July 1996 to February 1998, external PCS audits were performed for 37 institutions nationwide and detailed information of 561 esophageal cancer patients treated during the period 1992–1994 was collected by using the fifth PCS data format developed in the United States. This format was provided courtesy of the American College of Radiology. For this study, patients who had not undergone surgery ( n = 336) were selected. The patients were classified into three age groups: < 65 years old ( n = 119), between 65 and 74 years ( n = 93), and 75 years or older ( n =123). Cox’s proportional hazards model was used for the statistical analysis, with survival, acute/subacute complication and late complication of grade 3 or more based on RTOG criteria, as the endpoints. Results: Significant prognostic factors for the entire non-surgery group were Karnofsky Performance Status (KPS) ( p = 0.0007), stage ( p = 0.0001), and external irradiation dose ( p = 0.0001). For the younger group, KPS ( p = 0.0004), stage ( p = 0.0197), and utilization of brachytherapy ( p = 0.0010) were significant, while for the intermediate age group it was KPS ( p = 0.0027), history of pulmonary disease ( p = 0.0339), stage ( p = 0.0001), and external dose ( p = 0.0001), and for the elderly group, stage ( p = 0.0001) and external irradiation dose ( p = 0.0224) were significant. Significant risk factors for complications for the entire group were stage ( p = 0.0411), external dose ( p = 0.0163), and stratification of institution (academic vs. nonacademic) ( p = 0.0114). Significant risk factors for the younger group were history of pulmonary disease ( p = 0.0495) and external dose ( p = 0.0037), and the other age groups showed no significant risk factors. Conclusion: Age was not a significant prognostic or risk factor for esophageal cancer patients in the non-surgery group treated with radiation therapy. Therefore, radiation therapy represented an important treatment modality for the elderly as well as for the younger esophageal cancer patients. External dose was a treatment-related prognostic factor for the elderly as well as for the intermediate age group.