Use of Capecitabine Monotherapy and in Combination with Oxaliplatin as Adjuvant Chemotherapy for Locally Advanced Colorectal Cancer in Elderly Patients: A Clinical Trial Protocol

Abstract

Introduction. Adjuvant chemotherapy radical surgical resection of colorectal cancer (CRC) is well established in clinical practice. However, its role in the elderly population remains a subject of debate.

Materials and Methods. This is a planned single-center, open-label, randomized phase II trial. Groups of elderly patients (aged ≥ 70 years) with locally advanced CRC who underwent radical surgery as the first phase of treatment will be analyzed. Patients in the first group will receive adjuvant fluoropyrimidine monotherapy (capecitabine), while those in the second group will receive a standard platinum-based polychemotherapy regimen (XELOX). In both groups, a comprehensive geriatric assessment and polymerase chain reaction (PCR)-based determination of dihydropyrimidine dehydrogenase (DPD) deficiency in blood are planned prior to randomization. The primary endpoint is 3-year recurrence-free survival; the secondary endpoint is 5-year overall survival. To detect a 10 % difference in 3-year recurrence-free survival at a significance level of p ≤ 0.05 and a power of 0.8, approximately 70 patients per group are required. Accounting for a projected dropout rate of 20 %, the required sample size is 80 patients per group, yielding a total of 160 patients.

Conclusion. We hypothesize that oxaliplatin-based chemotherapy has a manageable toxicity profile and is effective in reducing CRC recurrence rates in elderly patients. Therefore, every effort should be made to administer full-course adjuvant therapy in this patient population, with the active integration of comprehensive geriatric assessment into routine clinical practice.