Urinary Metabolites as Biomarkers of Early Radiation Cystitis in Patients With Prostate Cancer Undergoing Radiotherapy.

Background/aim: Treatment-related bladder toxicities are a primary concern in the management of prostate cancer radiotherapy. This study aimed to identify urinary metabolites that can predict early radiation cystitis-related toxicities in patients undergoing radiotherapy for prostate cancer.

Patients and methods: Patients' clinical characteristics and urine samples were collected before, two weeks after, at the end, and three months after the initiation of radiotherapy and subsequently analyzed. Capillary electrophoresis-mass spectrometry and liquid chromatography-mass spectrometry were used for comprehensive quantification of urinary metabolites. Multivariate analysis was conducted to identify potential protective factors against the early toxicities of radiation cystitis.

Results: A total of 176 samples were obtained from 44 patients. Betaine, tartrate, N,N-dimethylglycine, and homocarnosine were identified as independent protective factors against early toxicities of radiation cystitis among various potential confounding metabolic factors. Comorbid diabetes mellitus was also identified as a protective factor.

Conclusion: Betaine, tartrate, N,N-dimethylglycine, and homocarnosine were identified as protective urinary metabolites against early radiation cystitis. Urinary metabolomic profiling may be a useful tool for investigating disease metabolism in metabolic disorders and cancers. Its ease of use and repeatability make it an optimal method for patient follow-up.