Association of Preoperative Physical Activity with Short- and Long-Term Outcomes in Patients Undergoing Palliative Resection for Metastatic Colorectal Cancer: An Inverse Probability of Treatment Weighting Analysis

SIMPLE SUMMARY: Physical activity is linked to the risk and the prognosis of colorectal cancer. However, the impact of preoperative physical activity on postoperative short-term and long-term outcomes is limited. The aim of our study was to elucidate the relationship of preoperative physical activity and postoperative outcomes in metastatic colorectal cancer patients who underwent palliative resection. After the inverse probability of the treatment weighting process, the metabolic equivalent of task < 12 group had a higher postoperative morbidity rate and mortality rate. No significant difference was found in overall survival. In patients undergoing palliative resection for metastatic colorectal cancer, preoperative leisure-time physical activity with the metabolic equivalent of task ≥ 12 was associated with reduced short-term postoperative morbidity and mortality; however, no difference was detected in long-term survival. ABSTRACT: A lack of physical activity is a generally accepted risk factor for colorectal cancer. However, research on the effect of preoperative physical activity on postoperative and long-term outcomes is limited, especially in patients with stage IV colorectal cancer who underwent palliative surgery. Patients who underwent bowel resection for stage IV primary colorectal cancer between January 1995 and December 2016 were retrospectively enrolled. A total of 2185 patients were divided into two groups according to preoperative leisure-time weekly physical activity as assessed by metabolic equivalent of task (MET) values: MET < 12 (n = 1845) and MET ≥ 12 (n = 340). Inverse probability of treatment weighting (IPTW) was used to reduce imbalance and selection biases between the two groups. After the IPTW process, the MET < 12 group showed a higher postoperative morbidity rate (18.7% vs. 10.6%; p < 0.001) and mortality rate (2.4% vs. 0.6%; p < 0.001) than the MET ≥ 12 group. No significant difference was found in overall survival. Weekly preoperative leisure-time physical activity with MET ≥ 12 was associated with reduced short-term postoperative morbidity and mortality in patients undergoing palliative resection for metastatic colorectal cancer. However, no difference was detected in long-term survival.