Oncologic outcomes of colorectal cancer in octogenarians
Authors: Oh Soo Young , Park Jung Yun , Yang Kwan Mo , Jung Seong-A , Kwon Yong Jae , Jung Yun Tae , Ma Chung Hyeun , Yun Keong Won , Yoon Kwang Hyun , Kwak Jae Young , Yu Chang Sik 
Published: September 2023

Introduction
Octogenarians constitute a growing number of diagnoses for colorectal cancer. However, the optimal treatment for these increasingly vulnerable octogenarians with colorectal cancer remains a challenging issue. The aim of this study was to evaluate the oncologic outcomes of colorectal cancer, comparing octogenarians (>80 years) and younger age (60-79 years).
Methods
A total of 657 patients underwent surgery for colorectal cancer between January 2015 and December 2019 at Gangneung asan hospital. Among them, 491 patients over the age of 60 were enrolled. The exclusion criteria were as follows: only local resection, R1 and R2 resection, absence of data in follow-up, concurrent inflammatory bowel disease, concurrent malignancy, and prior history of malignancy. The patients were divided into two groups according to their age: Octogenarian group (OG, aged > 80 years, n=93), and younger group (YG, aged 60 to 79 years, n=398).
Results
The mean follow-up was 41.8 months (range 1 to 89.4 months). OG showed higher rate of emergency surgery (25.8% vs. 13.6% p=0.004), higher mortality rates (47.3% vs. 25.9%, p<0.001) and received less adjuvant therapy (17.2% vs. 59.5%, p<0.001). Indeed, anastomosis rates in rectal cancer were significantly lower in OG (65.2% vs. 81.1%, p=0.043). Location of tumor, TNM stage, differentiation, retrieved lymph nodes, presence of lymphovascular invasion or perineural invasion, and tumor size were not difference in two groups.
OG had poorer 3-year overall survival (61.2% vs. 81.3%, P<0.001), however, 3-year disease-free survival was comparable between YG (81.2% vs. 87.2%, p=0.177). In multivariate analysis, emergency operation (hazard ratio [HR] = 2.137, 95% confidence interval [CI]: 1.465-3.116, p=0.001), severe complications (HR=1.788, 95% CI: 1.133-2.823, p=0.013), poorly differentiation (HR=2.806, 95% CI: 1.377-5.718, p=0.004), higher TNM stage (HR=6.257, 95% CI: 2.434-16.082, p=0.001), presence of perineural invasion (HR=1.572, 95% CI: 1.092-2.264, p=0.015), and less receiving adjuvant chemotherapy (HR=2.599, 95% CI: 1.735-3.894, p=0.001) were independent factor for worse overall survival. Similarly, Independent associations for recurrence were higher TNM stage (HR=6.887, 95% CI: 2.515-18.864, p=0.001), emergency surgery (HR=2.377, 95% CI: 1.380-4.097, p=0.002), the presence of perineural invasion (HR=1.861, 95% CI: 1.142-3.032, p=0.013), poor differentiation (HR=2.813, 95% CI: 1.221-6.478, p=0.015), and less receiving adjuvant chemotherapy (HR=2.314, 95% CI: 1.315-3.462, p=0.002). Age was not independent factor for recurrence. In OG, patients with no or mild complication (Clavien-Dindo 1-2) had significantly higher 3-year OS (72.8% vs. 38.8%, p<0.001) than patients with severe complications (Clavien-Dindo 3-5).
Conclusion
Try to reduce postoperative complication, screening to avoid emergency setting, and receiving adjuvant treatment would have potential to improve oncologic outcomes of octogenarians with colorectal cancer.