Serotonin Levels and Chemotherapy-Induced Nausea and Vomiting in Cancer Patients: A Cross-Sectional Study.

Introduction: Nausea and vomiting are distressing symptoms experienced by cancer patients undergoing treatment, impacting their physical well-being and quality of life. Serotonin, a neurotransmitter known for its role in regulating mood and gastrointestinal function, has been implicated in chemotherapy-induced nausea and vomiting (CINV). This study aimed to investigate serotonin level differences between CINV and non-CINV groups among cancer patients undergoing chemotherapy.

Methods: An analytical observational investigation utilizing a cross-sectional design was conducted at Dr. Kariadi General Hospital from 2021-2022. Non-random consecutive sampling was employed to select participants meeting inclusion criteria, including age between 18 and 65 years, undergoing chemotherapy, non-smoking, and no recent antibiotic use. Platelet-poor plasma samples were analyzed for serotonin levels using a radioimmunoassay kit (Microplate reader ELx800).

Results: This study included 61 subjects compared serotonin levels in two groups to investigate their potential association with chemotherapy-induced nausea and vomiting (CINV). The non-CINV group (n=31) had a median serotonin level of 70 (IQR: 20) ng/mL, while the CINV group (n=30) had a significantly higher median of 170 ng/mL (IQR: 50) ng/mL. Age was associated with a 1.2 ng/mL increase in serotonin per year (95% CI: 0.5-1.9, p = 0.002), adjusted for sex. Being male correlated with a 40 ng/mL increase (95% CI: 10-70, p = 0.010), adjusted for age.

Conclusion: This study underscores the importance of understanding serotonin's role in CINV and highlights the need for tailored treatment approaches based on chemotherapy emetogenicity.