Population-Based Patterns and Factors Associated With Underuse of Palliative Systemic Therapy in Elderly Patients With Metastatic Colon Cancer

Elderly (>= 70 years) and young (< 70 years) patients with metastatic colon cancer were identified and their treatments and outcomes compared. The rates of adverse events, frequency of treatment interruptions, and magnitude of survival benefit from systemic therapy were similar between carefully selected elderly and young patients. Background: We compared the patterns and factors associated with chemotherapy and bevacizumab use in elderly versus young patients with metastatic colon cancer (mCC) and determined the effect of systemic therapy on overall survival (OS) according to age. Materials and Methods: Patients diagnosed with mCC from 2009 to 2010 in British Columbia, Canada were reviewed and categorized as elderly patients (age >= 70 years) and young patients (age < 70 years). Cox regression models adjusted for age and confounders were used to determine the effect of systemic therapy on OS. Results: We identified 1013 patients with a median age of 67 years. Of the 1013 patients, 42% were elderly and 58% were young; 57% were men; and 66% had an Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 or 1. Fewer elderly patients were offered systemic therapy compared with young patients (48% vs. 77%; P < .001). Among those treated, elderly patients were less likely than young patients to receive combination chemotherapy (47% vs. 81%; P < .0001) and bevacizumab (19% vs. 47%; P < .0001). The most common reasons for no treatment were similar for the elderly and young patients: patient choice, poor ECOG PS, and significant comorbidities. Advanced age alone was also cited as a reason for elderly but not for young patients (7% vs. 0%). When treated, the risk of adverse events and treatment interruptions was comparable between age groups. The receipt of systemic therapy was associated with improved OS in both elderly (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.37-0.56; P < .0001) and young (HR, 0.43; 95% CI, 0.35-0.53; P < .0001) patients, regardless of age (interaction P > .05). Conclusion: In carefully selected elderly patients, the outcomes from systemic therapy were comparable to those for young patients. Thus, age alone should not be a barrier to treatment of mCC.