Eligibility of Real-World Patients With Stage II and III Colon Cancer for Adjuvant Chemotherapy Trials.

INTRODUCTION

The results of adjuvant chemotherapy trials in stage II and III colon cancer are often extrapolated to real-world patients. This study was conducted to determine the proportion of real-world patients with stage II/III colon cancer who would be eligible for adjuvant chemotherapy trials and to compare the outcomes among eligible versus ineligible patients.

PATIENTS AND METHODS

We identified all patients diagnosed with stage II/III colon cancer between 2004 and 2015 from a large province in Canada. Patients meeting any one of the following criteria were considered ineligible: age > 75 years, anemia, comorbid conditions (heart disease, uncontrolled diabetes, kidney disease, liver disease), and a history of malignancy or immunosuppression. Cox regression models were constructed to determine the factors predicting overall and cancer-specific survival.

RESULTS

A total of 7841 patients with stage II/III colon cancer were identified, of whom 52.0% were men and median age at diagnosis was 71 years. Approximately 58.6% of patients were deemed trial ineligible; the most common reasons for ineligibility included advanced age (36.2%), renal dysfunction (26.9%), and cardiac disease (17.4%). In the real-world setting, 54.0% of eligible patients received adjuvant chemotherapy compared to 23.2% of ineligible patients (odds ratio, 3.89; 95% confidence interval, 3.53-4.28; P < .0001). The 5-year overall and cancer-specific survival of trial-ineligible patients who received adjuvant chemotherapy was significantly better than those treated with surgery alone.

CONCLUSION

The eligibility criteria of adjuvant chemotherapy trials in colon cancer should be broadened to be more representative of real-world patients.