Comparison of 30-day, 90-day and in-hospital postoperative mortality for eight different cancer types.

Background: Various definitions are used to calculate postoperative mortality. As variation hampers comparability between reports, a study was performed to evaluate the impact of using different definitions for several types of cancer surgery.

Methods: Population-based data for the period 1997-2008 were retrieved from the Rotterdam Cancer Registry for resectional surgery of oesophageal, gastric, colonic, rectal, breast, lung, renal and bladder cancer. Postoperative deaths were tabulated as 30-day, in-hospital or 90-day mortality. Postdischarge deaths were defined as those occurring after discharge from hospital but within 30 days.

Results: This study included 40,474 patients. Thirty-day mortality rates were highest after gastric (8·8 per cent) and colonic (6·0 per cent) surgery, and lowest after breast (0·2 per cent) and renal (2·0 per cent) procedures. For most tumour types, the difference between 30-day and in-hospital rates was less than 1 per cent. For bladder and oesophageal cancer, however, the in-hospital mortality rate was considerably higher at 5·1 per cent (+1·3 per cent) and 7·3 per cent (+2·8 per cent) respectively. For gastric, colonic and lung cancer, 1·0 per cent of patients died after discharge. For gastric, lung and bladder cancer, more than 3 per cent of patients died between discharge and 90 days.

Conclusion: The 30-day definition is recommended as an international standard because it includes the great majority of surgery-related deaths and is not subject to discharge procedures. The 90-day definition, however, captures mortality from multiple causes; although this may be of less interest to surgeons, the data may be valuable when providing information to patients before surgery.