External Validity of Two Scores for Predicting the Risk of Chemotherapy Toxicity Among Older Patients With Solid Tumors: Results From the ELCAPA Prospective Cohort

Background: Severe chemotherapy-related toxicities are frequent among older patients. The Chemotherapy Risk Assessment Scale for High-Age Patients (CRASH) and the Cancer and Aging Research Group Study (CARG) score were both developed to predict these events. Patients and Methods: The objective of this study was to evaluate the scores' predictive performance in a prospective cohort, which included patients aged 70 years and older referred for a geriatric assessment prior to chemotherapy for a solid tumor. The main endpoints were grades 3/4/5 toxicities for the CARG score and grades 4/5 hematologic toxicities and grades 3/4/5 non-hematologic toxicities for the CRASH score. Results: A total of 248 patients were included, of which 150 (61%) and 126 (51%) experienced at least one severe adverse event as defined respectively in CARG and CRASH studies. The incidence of adverse events was not significantly greater in the intermediate and high-risk CARG groups than in the low-risk group (odds ratio (OR) [95% CI] = 0.3 [0.1-1.4] (P =. 1) and 0.4 [0.1-1.7], respectively). The area under curve (AUC) was 0.55. Similarly, the incidence of severe toxicities was no greater in the intermediate-low, intermediate-high, and high-risk CRASH groups than in the low-risk CRASH group (OR [95%CI] = 1 [0.3-3.6], 1 [0.3-3.4], and 1.5 [0.3-8.1], respectively). The AUC was 0.52. The type of cancer, performance status, comorbidities, body mass index, and MAX2 index were independently associated with grades 3/4/5 toxicities. Conclusion: In an external cohort of older patients referred for a pretherapeutic GA, the CARG and CRASH scores were poor predictors of the risk of chemotherapy severe toxicities.