Comparative overall survival in T4N0 and T2-3N1 non-metastatic colon cancer: a retrospective cohort study

BACKGROUND:
The prognostic significance of pathological T stage relative to nodal involvement in colon cancer remains controversial. Emerging evidence suggests that patients with T4N0 disease may experience outcomes comparable to or worse than those with node-positive disease.


OBJECTIVES:
This study aimed to compare long-term oncologic outcomes between patients with non-metastatic T4N0 colon cancer and those with T2–3N1 disease.


DESIGN:
Retrospective


SETTINGS:
Single-center


PATIENTS AND METHODS:
Retrospective analysis of patients with histologically confirmed, non-metastatic colon adenocarcinoma who underwent curative-intent surgery between 1999 and 2020. Patients were categorized into T4N0 and T2–3N1 groups.


MAIN OUTCOME MEASURES:
Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan–Meier method and compared with log-rank tests. Prognostic factors were assessed using univariate and multivariate Cox proportional hazards models.


SAMPLE SIZE:
A total of 273 patients were included, of whom 78 (28.6%) were staged as T4N0 and 195 (71.4%) as T2–3N1.


RESULTS:

After a median follow-up of 72 months, patients with T4N0 disease showed significantly worse OS than those with T2–3N1 disease (HR=1.72, 95% CI 1.06–2.75;
P
=.02). Five-year OS rates were 66.6% and 79.8% in the T4N0 and T2–3N1 groups, respectively. On multivariate analysis, pathological T4N0 stage (HR=1.74, 95% CI 1.03–2.93;
P
=.03), age ≥65 years, vascular invasion, and omission of oxaliplatin-based adjuvant chemotherapy independently predicted poorer OS. Stage T4N0 was also associated with higher locoregional and distant recurrence rates, with increased peritoneal involvement.



CONCLUSIONS:
Non-metastatic T4N0 colon cancer is associated with less favorable long-term survival and higher recurrence rates compared with T2–3N1 disease, supporting its classification as a biologically aggressive subgroup that may benefit from treatment strategies similar to selected stage III colon cancers.


LIMITATIONS:
The retrospective, single-center design may introduce selection bias, and limited molecular data precluded detailed sub-group analyses.