[Analysis of risk factors for adverse outcomes in 10,135 patients with gastrointestinal malignancies aged 65 years and over who underwent elective surgery].

Objective: To explore the risk factors for postoperative adverse events in older persons with gastrointestinal malignancies and thus provide reference for selection of surgery and evaluation of such patients. Methods: An observational study design was employed, the study cohort comprising patients aged 65 years and over with gastrointestinal malignancies who underwent elective surgery in Peking University Cancer Hospital from 2008 to 2022. In this study, we compared the clinical characteristics (disease type, tumor stage), surgical safety (combined organ resection, operation duration, comorbidities), and treatment outcomes (postoperative complications, unplanned reoperation, and perioperative mortality) of these patients. Multivariate logistic regression analysis was conducted to identify risk factors associated with adverse outcomes. Results: The study cohort comprised 10,135 patients, of whom 74.7% (7,568) were 65-75 years old (excluding 75 years old), 23.6% (2,391) 75-85 years old (excluding 85 years old), and 1.7% (176) ≥85 years old. The type of cancer was colorectal in 63.4% (6,427 patients) and gastric in 36.6% (3,708); 62.0% (6,284/10,135)of the patients had stage II or III disease. The proportion of stage III and stage IV tumors was higher in patients aged over 85 years (47.4% [73/154) and 11.0% [17/154]), respectively, than in those aged 75-85 years (41.6% [854/2 051) and 8.2% [168/2 051]), respectively, and those aged 65-75 years (40.1% [2,576/6,431) and 10.9% [700/6,431]); these differences are statistically significant (χ²=27.95, P<0.01). Comorbidity was present in 50.6% (5,128/10,135) of the whole study cohort, comprising 58.0% (102/176) of those aged over 85 years, this being significantly higher than the 56.3% (1,346/2,391) in those aged 75-85 years and 48.6% (3,678/7,568) of those aged 65-75 years. The main comorbidities were hypertension (37.3%), diabetes (16.4%), and cardiovascular and cerebrovascular diseases (14.0%). Minimally invasive surgery was performed on 36.9% (3,740/10,135) of the whole study cohort, the 38.4% in 65-75 years old patients being significantly higher than the 32.5% in those aged 75-85 years and the 29.0% in those aged over 85 years; these differences are statistically significant (χ²=31.97, P<0.01). Preoperative neoadjuvant therapy was administered to 9.1% (924/10,135) of the whole study cohort, the proportion of patients receiving preoperative neoadjuvant therapy being significantly higher in those aged 65-75 years (11.1%) than in those aged 75-85 years (3.4%) and over 85 years (0.6%); these differences are statistically significant (χ²=148.98, P<0.01). Combined organ resection was performed in 4.9% (496/10,135) of the whole study cohort, the proportion undergoing combined organ resection being significantly lower in those aged over 85 years (2.3%) than in those aged 65-75 years (5.3%) and 75-85 years (3.8%); these differences are statistically significant (χ²=11.20, P<0.01). The mean operating time was (182.2±76.8) minutes, being significantly higher in those aged 65-75 years (186.6±78.3 minutes) than in those aged 75-85 years (169.4±71.3 minutes) and over 85 years (153.2±53.7 minutes); these differences are statistically significant (F=46.85, P<0.01). The overall incidence of postoperative complications was 10.9% (802/7,384); the incidence did not differ significantly between the three groups (P>0.05). The incidence of unplanned reoperation was 1.9% (193/10,135) and of death during hospitalization 0.3% (32/10,135). The perioperative mortality in the three groups was 1.1%, 0.5% and 0.2% in those aged over 85, 75-85, and 65-75 years, respectively. These differences are statistically significant (χ²=9.71, P<0.01). Among the patients with postoperative complications, 15.0% (120/802) underwent unplanned reoperation, which had a perioperative mortality of 1.0% (8/802), these rates being significantly higher than those for unplanned reoperation (1.1%, 73/6,582) and perioperative mortality (0.4%, 24/6,582) in patients without complications (all P<0.01). The median length of hospital stay was 11 days in patients aged over 85 years; this is significantly longer than the 9 days in those aged 65-75 years and 10 days in those aged 75-85 years (H=37.00, P<0.01). Multivariate logistic regression analysis showed that tumor stage IV (OR=1.56, 95%CI: 1.24-1.96, P<0.01), comorbidities (OR=1.26, 95%CI: 1.08-1.47, P<0.01), open surgery (OR=1.33, 95%CI: 1.13-1.56, P<0.01), and operation time >180 minutes (OR=1.82, 95%CI:1.53-2.15, P<0.01) were risk factors for adverse outcomes. Conclusion: Older patients with gastrointestinal tumors who have comorbidities and stage IV disease and undergo open surgery with a longer operation time are at higher risk of adverse outcomes than patients without these characteristics.