A historic cohort study of nutritional status related side effects and weight loss of cancer patients treated with immunotherapy

Background and aims: Recently, there has been an increase in the number of patients treated with immunotherapy. However, the number of studies investigating combination immunotherapies is still limited, resulting in a gap of knowledge regarding the incidence of nutritional side effects, differences in the durations of these side effects, and differences in weight loss between patients undergoing single and combination immunotherapies. Methods: In this historical cohort study, which was performed from 2017 to 2019, a total of 50 patients who received one type and 50 patients who received two types of immunotherapy were randomly selected, resulting in a sample of 100 patients. The primary objectives were to assess (a) the incidence of nutritional side effects, (b) the differences in the durations of these side effects, and (c) the differences in weight loss between the two groups. The secondary objectives were to assess the time to the first side effect, the time to the first unplanned hospital admission, unplanned hospital admissions, consultations from a dietitian, and nutritional interventions. Data were collected from the electronic patient record. Differences between groups were explored using the two-sample t-test, Mann–Whitney U test, Fisher exact test, or Wilcoxon rank sum test, depending on the type of data and the test assumptions. The time to the first side effect and the time to the first unplanned hospital admission are presented as Kaplan–Meier curves, and differences were calculated using a Cox proportional hazards model. Results: Patients undergoing a combination of two types of immunotherapy were found to have side effects for statistically significantly longer durations than patients receiving one type of immunotherapy (20 days versus 10 days, p = 0.045). Moreover, patients undergoing a combination of two types of immunotherapy were found to lose more weight (6.2 kg versus 1.2 kg, p < 0.001). At least one side effect was reported in 86% of the patients in the one-therapy group and in 90% of the patients in the combination-therapy group. Furthermore, a high incidence of decreased appetite (70% and 86%), nausea (52% and 68%), vomiting (22% and 46%), and diarrhea/colitis (56% and 54%) was found in both groups. However, the time to the first side effect and the time to the first hospital admission were not statistically significantly different between the one-therapy and combination-therapy groups. Of the total cohort, 26% were admitted unexpectedly during the immunotherapy because they developed immunotherapy-related side effects, whereas 38% of the patients in our sample consulted a dietitian. Conclusions: Nutritional side effects are common in patients treated with immunotherapy. Generally, treatment with a combination of two types of immunotherapy is associated with an increased incidence of nutritional side effects. These side effects last longer and patients lose more weight compared to those receiving one type of immunotherapy.