Postoperative mortality is traditionally defined as death within 30 days of surgery. We hypothesised that the declining 30-day mortality after oesophageal cancer resection is, at least partly, explained by a shift towards increased 90-day mortality.
This population-based cohort study included 95 % of all patients who underwent surgical resection for oesophageal cancer in Sweden in 1987–2010. Cox proportional-hazards regression models were used to calculate hazard ratios (HRs) with 95 % confidence intervals (CIs) of 30-day and 31–90 days postoperative mortality in three calendar periods (1987–1994, 1995–2002, and 2003–2010). Adjustments were made for age, sex, comorbidity, tumour stage, tumour histology, surgical radicality, neoadjuvant therapy, and hospital volume of oesophagectomy.
Among 1,822 patients, the 30-day postoperative mortality decreased from 9.3 % in 1987–1994 to 3.0 % in 2003–2010, while the corresponding 31–90 days mortality decreased from 8.4 to 4.6 %. The adjusted HR of 30-day mortality in the earliest period was markedly increased compared to the latest period (HR 3.26; 95 % CI 1.96–5.45), whereas the corresponding HR of 31–90 days mortality was weaker (HR 2.16; 95 % CI 1.34–3.46). Among patients who died within 90 days of surgery, the proportion of 31–90 days mortality increased from 47 to 61 % during the study period.
This population-based study indicates a shift of postoperative mortality following surgery for oesophageal cancer from 30 days to 31–90 days with more recent calendar periods. Reporting of 90-day mortality rates might replace 30-day mortality rates in assessing early postoperative mortality in oesophageal cancer patients.
2015. Vol. 22, no 9, 3144-3149 p.