Post-operative outcomes and predictors of mortality after colorectal cancer surgery in the very elderly patients

Background: The frailty of the very elderly patients who undergo surgery for colorectal cancer negatively influences postoperative mortality. This study aimed to identify risk factors for postoperative mortality in octogenarian and nonagenarian patients who underwent surgical treatment for colorectal cancer. Methods: This is a single institution retrospective study. The primary outcomes were risk factors for postoperative mortality. The variables of the octogenarians and nonagenarians were compared by using t-test, chi-square test, and Fisher exact test. A multivariate logistic regression analysis was carried out on the combined cohorts. Results: we identified 319 octogenarians and 43 nonagenarians (N = 362) who underwent surgery for colorectal cancer at the Sant'Orsola-Malpighi university hospital in Bologna between 2011 and 2015. The 30-day post-operative mortality was 6% (N = 18) among octogenarians and 21% (N = 9) for the nonagenarians. The groups significantly differed in the type of surgery (elective vs. urgent surgery, p < 0.0001), ASA score (p = 0.0003) and rates of 30-day postoperative mortality (6% vs. 21%, p = 0.0003). In the multivariate analysis ASA > III (OR 2.37, 95% CI [1.43\u20133.93], p < 0,001), and urgent surgery (OR 2.17, 95% CI [1.17\u20134.04], p = 0.014) were associated to post-operative mortality. On the contrary, pre-operative albumin 653.4 g/dL (OR 0.14, 95% CI [0.05\u20130.52], p = 0.001) was associated with a protective effect on postoperative mortality. Conclusions: In the very elderly affected by colorectal cancer, preoperative nutritional status and pre-existing comorbidities, rather than age itself, should be considered as selection criteria for surgery. Preoperative improvement of nutritional status and ASA risk assessment may be beneficial for stratification of patients and ultimately for optimizing outcomes