1. Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, Shandong Province, China;
2. Shandong Provincial Engineering and Technological Research Center for Liver Diseases Prevention and Control, Jinan 250021, Shandong Province, China;
3. Department of Cardiology, Central Hospital of Zibo, Zibo 255036, Shandong Province, China;
4. Department of Gastroenterology, The Fifth People's Hospital of Jinan, Jinan 250022, Shandong Province, China;
5. Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, Shandong Province, China;
6. Health Commission of Shandong Province, Jinan 250014, Shandong Province, China.
Objective: To investigate the prognostic value of the tumor size in colorectal cancer (CRC) patients with different primary tumor locations.
Patients and methods: We retrospectively recruited 3971 stage I-III CRC patients with curative resection. The propensity score matching technique was conducted to reduce the selection bias, producing a propensity score matched cohort of 1347 pairs of patients based on the tumor size (≤4 cm and >4 cm groups). Kaplan-Meier survival analyses and univariate and multivariate analyses were used to compare the overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS) between the two groups. Subgroup analyses which were stratified by primary tumor locations and several other baseline variables were also performed for conformation.
Results: In the propensity score matched cohort, the Kaplan-Meier survival curves revealed that patients with a tumor size less than 4 cm had similar OS, CSS and DFS, compared to patients with a tumor size greater than 4 cm. While in multivariate analyses, the smaller tumor size was an independent risk factor for CSS (HR, 1.275; 95% CI, 1.006-1.616; P=0.045). Subgroup analyses based on primary tumor locations further suggested that the smaller tumor size was significantly associated with worse OS (HR, 2.455; 95% CI, 1.297-4.649; P=0.006) and CSS (HR, 2.493; 95% CI, 1.202-5.174; P=0.014) in patients with right-side colon cancers (RCC).
Conclusions: Our propensity matching score study indicated that the smaller tumor size was an independent risk factor for CSS in patients with stage I-III CRC, and for OS and CSS in patients with RCC.
Keywords: tumor size, primary tumor location, colorectal cancer, prognosis, propensity score matching