Adjuvant chemotherapy is associated with improved overall survival in select patients with Stage II colon cancer: A National Cancer Database analysis

Abstract

Background and objectives: Guidelines for Stage II colon cancer recommend adjuvant chemotherapy (AC) only for tumors with high-risk features, but long-term outcomes data are mixed. We aimed to determine if AC was associated with a survival benefit in this population.

Methods: Patients were identified from the National Cancer Database and included if they met the following criteria: diagnosis of Stage II colon cancer, surgery, survival data, and complete data on six high-risk features. The cohort of 57 335 patients was stratified by receipt of AC. Subgroup analysis was performed on patients under the age of 65 years with no comorbidities. Overall survival (OS) was the primary endpoint.

Results: An increasing number of high-risk features was associated with significantly decreased median OS. AC was associated with significantly increased OS for patients with 0, 1, 2, and ≥3 high-risk features. On subgroup analysis, receipt of AC was associated with a reduced risk of death (hazard ratio: 0.66; confidence interval: 0.59-0.74). For patients in the subgroup who had a T4 tumor, AC was associated with increased OS (92.7 vs. 83.6 months).

Conclusions: AC should be considered for all younger, healthy patients with Stage II colon cancer and may be associated with a survival benefit for patients with T4 disease.

Keywords: NCDB; Stage II; adjuvant chemotherapy; colon cancer; high risk.

Figure 1.

Inclusion and exclusion criteria for the cohort of patients with Stage II colon cancer.

Figure 2.

Survival curves by number of high-risk features stratified by receipt of AC. A: OS for patients with 0 (87.6 months), 1 (82.8 months, p<0.001), 2 (77.2 months, p<0.001), or 3 or more high-risk features (64.8, p<0.001). B: OS of patients with 0 high-risk features by receipt of AC, 86.2 vs 99.9 months, p<0.001. C: OS of patients with 1 high-risk feature by receipt of AC, 79.3 vs 94.4 months, p<0.001. D: OS of patients with 2 high-risk features by receipt of AC, 70.7 vs 90.6 months, p<0.001. E: OS of patients with 3 or more high-risk features by receipt of AC, 56.2 vs 77.0 months, p<0.001.

Figure 3.

Survival curves of patients with T4 cancers among patients under 65 years old with no comorbidities by receipt of AC. A: Patients with any T4 lesion by receipt of AC, 83.6 vs 92.7 months, p<0.001. B: Patients with T4A lesions by receipt of AC, 85.4 vs 93.6 months, p<0.001. C: Patients with T4B lesions by receipt of AC, 80.4 vs 90.8 months, p<0.001.