To explore the change trajectory of dietary quality during chemotherapy in elderly patients with colorectal cancer by using group-based trajectory modeling,and to analyze the influencing factors of different trajectories.

A total of 204 elderly patients with colorectal cancer who underwent their first chemotherapy in three tertiary hospitals from July 2024 to January 2025 were selected from Tangshan city.On the day before the first course of the FOLFOX regimen/the day before the first course of the XELOX regimen(T0),General Information Questionnaire,Chinese Healthy Eating Index,Elderly Nutrition Literacy Scale,Perceived Social Support Scale,Brief Illness Perception Questionnaire were used to baseline survey.Chinese Healthy Diet Index was used to conduct dietary quality tracking survey on the day before the first course of the FOLFOX regimen/the day before the first course of the XELOX regimen(T1),the day before the first course of the FOLFOX regimen/the day before the second course of the XELOX regimen(T2),and the day before the first course of the FOLFOX regimen/the day before the fourth course of the XELOX regimen(T3).The group-based trajectory modeling was used to identify the potential categories of the trajectory changes in dietary quality.Univariate analysis and multiple Logistic regression analysis were used to analyze the influencing factors.

The dietary quality of elderly colorectal cancer patients during chemotherapy were divided into four trajectory changes:low-level continuous group(8.33%),low-level increasing group(35.29%),high-level continuous group(25.49%),and medium-level increasing group(30.88%).Logistic regression analysis results showed that disease perception,main types of work before retirement,medical payment methods,and nutritional literacy were the influencing factors of different trajectories of dietary quality in elderly colorectal cancer patients during chemotherapy(P<0.05).

There is group heterogeneity in the trajectory of dietary quality changes during chemotherapy in elderly patients with colorectal cancer.Attention should be paid to the dynamic assessment of dietary quality for patients who engage in physical labor before retirement and those who are covered by employee medical insurance.At the same time,the predictive role of nutritional literacy and disease perception in the trajectory of dietary quality changes should be emphasized.A dynamic intervention plan should be constructed with the core of improving the nutritional literacy and establishing correct disease perception of elderly patients with colorectal cancer during chemotherapy to improve their dietary quality and nutritional level throughout the chemotherapy process.