Aged Aged, 80 and over Cancer Care Facilities--standards Colectomy--mortality Colonic Neoplasms--mortality Confidence Intervals Cross-Sectional Studies Esophageal Neoplasms--mortality Esophagectomy--mortality Female Health Care Surveys--statistics & numerical data Health Services Research--statistics & numerical data Hospital Mortality Humans Internet--statistics & numerical data Male Middle Aged Odds Ratio Outcome Assessment, Health Care--statistics & numerical data Pancreatectomy--mortality Pancreatic Neoplasms--mortality Quality Indicators, Health Care--statistics & numerical data Quality of Health Care--statistics & numerical data Retrospective Studies Risk Adjustment--statistics & numerical data United States