DOSAGE study: protocol for a phase III non-inferiority randomised trial investigating dose-reduced chemotherapy for advanced colorectal cancer in older patients.

INTRODUCTION: Treating older adults with chemotherapy remains a challenge, given their under-representation in clinical trials and the lack of robust treatment guidelines for this population. Moreover, older patients, especially those with frailty, have an increased risk of developing chemotherapy-related toxicity, resulting in a decreased quality of life (QoL), increased hospitalisations and high healthcare costs. Phase II trials have suggested that upfront dose reduction of chemotherapy can reduce toxicity rates while maintaining efficacy, leading to fewer treatment discontinuations and an improved QoL. The DOSAGE aims to show that upfront dose-reduced chemotherapy in older patients with metastatic colorectal cancer is non-inferior to full-dose treatment in terms of progression-free survival (PFS), with adaption of the treatment plan (monotherapy or doublet chemotherapy) based on expected risk of treatment toxicity. METHODS AND ANALYSIS: The DOSAGE study is an investigator-initiated phase III, open-label, non-inferiority, randomised controlled trial in patients aged≥70 years with metastatic colorectal cancer eligible for palliative chemotherapy. Based on toxicity risk, assessed using the Geriatric 8 (G8) tool, patients will be stratified to either doublet chemotherapy (fluoropyrimidine with oxaliplatin) or fluoropyrimidine monotherapy. Patients classified as low risk will be randomised between a fluoropyrimidine plus oxaliplatin in either full-dose or with an upfront dose reduction of 25%. Patients classified as high risk will be randomised between fluoropyrimidine monotherapy in either full-dose or with an upfront dose reduction. In the dose-reduced arm, dose escalation after two cycles is allowed. The primary outcome is PFS. Secondary endpoints include grade≥3 toxicity, QoL, physical functioning, number of treatment cycles, dose reductions, hospital admissions, overall survival, cumulative received dosage and cost-effectiveness. Considering a median PFS of 8 months and non-inferiority margin of 8 weeks, we shall include 587 patients. The study will be enrolled in 36 Dutch Hospitals, with enrolment scheduled to start in July 2024. This study will provide new evidence regarding the effect of dose-reduced chemotherapy on survival and treatment outcomes, as well as the use of the G8 to choose between doublet chemotherapy or monotherapy. Results will contribute to a more individualised approach in older patients with metastatic colorectal cancer, potentially leading to improved QoL while maintaining survival benefits. ETHICS AND DISSEMINATION: This trial has received ethical approval by the ethical committee Leiden Den Haag Delft (P24.018) and will be approved by the Institutional Ethical Committee of the participating institutions. The results will be disseminated in peer-reviewed scientific journals. TRIAL REGISTRATION NUMBER: NCT06275958.

Tolerability and effectiveness of palbociclib in older women with metastatic breast cancer.

PURPOSE: Palbociclib has become the standard of care for estrogen receptor-positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer, but real-world evidence in older women remains scarce. Therefore, we investigated tolerability of palbociclib in older women with metastatic breast cancer. METHODS: Consecutive women aged ≥ 70 with ER+/HER2- metastatic breast cancer, treated with palbociclib in any treatment line in six hospitals, were included. Primary endpoint was grade ≥ 3 palbociclib-related toxicity. Predictors of toxicity were identified using logistic regression models. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan Meier. RESULTS: We included 144 women with a median age of 74 years. Grade 3-4 toxicity occurred in 54% of patients, of which neutropenia (37%) was most common. No neutropenic fever or grade 5 toxicity occurred. Dose reduction during treatment occurred in 50% of patients, 8% discontinued treatment due to toxicity and 3% were hospitalized due to toxicity. Polypharmacy (odds ratio (OR) 2.50; 95% confidence interval (CI) 1.12-5.58) and pretreatment low leukocytes (OR 4.81; 95% CI 1.27-18.21) were associated with grade 3-4 toxicity, while comorbidities were not. In first-line systemic therapy, median PFS was 12 months and median OS 32 months. In second-line, median PFS was 12 months and median OS 31 months. CONCLUSION: Although grade 3-4 toxicity and dose reductions occurred frequently, most were expected and managed by dose reductions, showing that palbociclib is generally well tolerated and thus represents a valuable treatment option in the older population.

Time trends in treatment patterns and survival of older patients with synchronous metastatic colorectal cancer in the Netherlands: A population-based study.

New treatment strategies have improved survival of metastatic colorectal cancer in trials. However, it is not clear whether older patients benefit from these novel therapies, as they are often not included in pivotal trials. Therefore, we investigated treatment patterns and overall survival over time in older patients with metastatic colorectal cancer in a population-based study. We identified 22.192 Dutch patients aged ≥70 years diagnosed with synchronous metastatic colorectal cancer between 2005 and 2020 from the Netherlands Cancer Registry. Changes in treatment over time were assessed with logistic regression models. Survival was assessed by Cox proportional hazard ratios (HR). Results showed that chemotherapy use increased between 2005 and 2015, but declined from 2015 onwards, while more patients received best supportive care. Over time, fewer patients underwent primary tumor resection alone. Although survival of both metastatic colon and rectal cancer improved until 2014, survival of colon cancer decreased from 2014 onwards (HR 1.04, 95% confidence interval [CI] 1.01-1.05), which was seen in all age groups. Survival of metastatic rectal cancer patients remained unchanged from 2014 onwards (HR 1.00, 95% CI 0.98-1.03) in all age groups. In conclusion, treatment patterns of Dutch older patients with synchronous metastatic colorectal cancer rapidly changed from 2005 to 2020, with increasing percentages of patients receiving best supportive care. Survival of metastatic colon cancer decreased from 2014 onwards. The implementation of a colorectal cancer screening program and patient selection might explain why only a subset of older patients seem to benefit from the availability of novel treatment options.