Efficacy and Safety of Single Agent or Combination Adjuvant Chemotherapy in Elderly Patients With Colon Cancer: A Canadian Cancer Institute Experience

The pattern of adjuvant chemotherapy (AC) use, toxicity profile, and survival benefit in elderly patients with colon cancer is unclear. Therefore, we evaluated the treatment patterns, toxicity profile, and survival of elderly patients with stage Ill colon cancer at our institution. Single-agent chemotherapy was used more frequently than combination chemotherapy in elderly patients. Those who were treated with combination chemotherapy experienced increased toxicity and did not receive a survival benefit. Background: The pattern of adjuvant chemotherapy (AC) use, toxicity profile, and survival benefit in elderly patients with colon cancer (CC) is unclear. We sought to (1) determine whether patients >= 65 years with stage Ill CC were offered single-agent or combination AC, (2) evaluate the reason for selecting single-agent versus combination AC, (3) evaluate the toxicity profile of single-agent and combination AC in the elderly, and (4) determine whether a survival benefit exists for elderly patients receiving combination AC. Patients and Methods: A retrospective analysis of records of patients >= 65 years diagnosed with stage III CC from 2004 to 2010 was performed to identify baseline characteristics, AC protocols, toxicity, dose intensity, and survival. Results: Two hundred sixty-eight patients >= 65 years were diagnosed and treated with AC from 2004 to 2010. Of these patients, 178 were treated with single-agent AC and 90 were treated with combination AC. The most common reasons for choosing single-agent AC were patient preference, comorbidities, and lack of drug coverage. For each year over 65 years, the odds of receiving combination over single-agent AC decreased by 22%. There were more dose delays, dose reductions, and early chemotherapy discontinuation in the combination AC group because of hematologic toxicity. The 5-year overall survival (OS) was 73% in patients who received single-agent AC compared with 84% in those who received combination AC. There was no difference in cancer-related deaths between the groups. Conclusion: In elderly patients treated with AC for stage III CC, single-agent AC is used more frequently than combination AC, based on age, comorbidities, and patient choice. Toxicity with combination AC in elderly patients is high. No survival benefit was seen with combination AC over single-agent AC. (C) 2014 Elsevier Inc. All rights reserved.