Patients with stage 2 or 3 CDX2-negative colon cancer might benefit from adjuvant chemotherapy and adjuvant chemotherapy may be a treatment option for patients with CDX2-negative stage 2 disease who typically receive surgery alone, according to a study published in The New England Journal of Medicine.1
Because it is important to identify patients with high-risk stage 2 colon cancer who may benefit from adjuvant treatment after surgery, researchers sought to search for biomarkers of colon epithelial differentiation to better identify these patients.
In their screening test for biomarkers, researchers found that 87 of 2115 tumor samples lacked expression of the transcription factor CDX2. Results showed that 5-year disease-free survival was lower among the 32 of 466 discovery data set patients with CDX2-negative colon cancers than among the 434 patients with CDX2-positive colon cancer (HR, 3.44; 95% CI, 1.60 – 7.38; P = .002).
Then in the validation set of 314 patients, results showed that the rate of 5-year disease-free survival was lower among the 38 patients with CDX2 protein-negative colon cancers compared with the 276 with CDX2 protein-positive tumors (HR, 2.42; 95% CI, 1.36 – 4.29; P = .003). Results in both sets were independent of patient’s age, sex, and tumor stage and grade.
Subgroup analyses of the discovery data set and the validation set further demonstrated that among patients with stage 2 colon cancer, 5-year disease-free survival was significantly lower in patients with CDX2-negative tumors than those with CDX2-positive tumors (P = .003 and P = .004, respectively).
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In addition, when researchers analyzed a pooled database of all patient cohorts, they found that the 5-year disease-free survival rate was 91% in the 23 patients with stage 2 CDX2-negative tumors who were treated with adjuvant chemotherapy compared with 56% among the 25 patients not treated with adjuvant chemotherapy (P = .006).
- Dalerba P, Sahoo D, Paik S, et al. CDX2 as a prognostic biomarker in stage II and stage III colon cancer. NEJM. 2016; 374(3):211-222.