DOSAGE Study: Upfront Dose-Reduced Chemotherapy in Older Patients with Metastatic Colorectal Cancer

Candidates for Palliative Chemotherapy, Colorectal Cancer, Metastatic Cancer, Older Patients

Dose-reduced Chemotherapy, Upfront Reduction, Palliative Chemotherapy, Non-inferiority

The goal of this phase III, open-label, non-inferiority randomized controlled clinical trial is compare upfront dose-reduced chemotherapy with the standard dose chemotherapy in older patients ( ≥70 years) with metastasized colorectal cancer, with regard to progression-free survival (PFS). The choice between monotherapy (a fluoropyrimidine) and doublet chemotherapy (a fluoropyrimidine with oxaliplatin) will be made for each individual patient based on expected risk of chemotherapy toxicity (according to the G8 screening). Patients classified as low risk of toxicity will be randomized between doublet chemotherapy in either full-dose, or with an upfront dose-reduction of 25%. Patients classified as high risk will be randomized between monotherapy in either full-dose or upfront dose-reduction. Primary outcome is PFS. Secondary endpoints include grade ≥3 toxicity, QoL, physical functioning, overall survival, number of treatment cycles, dose reductions, hospital admissions, cumulative received dosage and cost-effectiveness.

Treating older adults with chemotherapy remains a challenge, as they are strongly underrepresented in clinical trials and no robust guidelines for treating older patients exist. Moreover, older adults are at increased risk of chemotherapy-related toxicity, resulting in decreased quality of life (QoL), increased hospital admissions and high health care costs. Therefore, the aim of the DOSAGE study is to demonstrate that upfront dose-reduced chemotherapy in patients with metastasized colorectal cancer is non-inferior to full-dose treatment with regard to progression-free survival (PFS). Treatment plans (monotherapy or doublet chemotherapy) will be based on expected risk of treatment toxicity for the individual patient (according to the Geriatric 8 (G8) questionnaire). The investigators expect that this treatment strategy will lead to less grade ≥3 toxicity, less early treatment continuation and hospitalizations and a better QoL and physical functioning. The DOSAGE study is a phase III, open-label, non-inferiority, randomized controlled clinical trial in patients aged ≥70 years with metastasized colorectal cancer eligible for palliative chemotherapy. All participating patients will undergo geriatric screening by the G8 questionnaire and will be classified as low risk of toxicity (G8-score of 15 or higher) or high risk of toxicity (G8-score of 14 or lower or judged as high toxicity risk by their treating oncologist). Patients classified as low risk will be randomized between a fluoropyrimidine and oxaliplatin in either full-dose, or with an upfront dose-reduction of 25%. Patients classified as high risk will be randomized between fluoropyrimidine monotherapy in either full-dose or upfront dose-reduction. Addition of targeted treatment (bevacizumab or epidermal growth factor receptor (EGFR) inhibition) is allowed. Patients with a moderate renal impairment (GFR 30- 50 mL/min) will be treated with 25% reduced starting dose of capecitabine when randomized for full dose treatment and treated with 40% reduced starting dose when randomized for upfront dose reduction. Primary outcome is PFS. Secondary endpoints include grade ≥3 toxicity, QoL, physical functioning, overall survival, number of treatment cycles, dose reductions, hospital admissions, cumulative received dosage and cost-effectiveness. Given a non-inferiority margin of 8 weeks, 587 patients will be included (293/292 patients per arm).

Netherlands