JMIR Publications

ABSTRACT

Background:

Despite advances in radiation techniques, radiation cystitis (RC) remains a significant cause of morbidity from pelvic radiotherapy, which may affect patients' quality of life (QoL). The pathophysiology of RC is not well understood, which limits the development of effective treatments.

Objective:

The RABBIO study aims to investigate the correlation between blood and urinary biomarkers and the intensity of acute RC symptoms and QoL in patients undergoing localized prostate cancer radiotherapy.

Methods:

The study included patients with low or intermediate-risk localized prostate cancer who were eligible for localized radiotherapy. Blood and urinary biomarkers were analyzed before radiotherapy was initiated and at weeks 4 and 12 of radiation therapy. Patients completed questionnaires related to radiation cystitis symptoms and QoL using a digital remote monitoring platform. The information was processed by means of an algorithm which classified patients according to the severity of symptoms and adverse events reported. Levels of blood and urinary biomarkers were correlated with the severity of acute RC symptoms and patient-reported QoL.

Results:

401 adverse events’ questionnaires were collected over the duration of the study. The most frequently reported adverse events at week 4 were pollakiuria, constipation, and diarrhea. In comparison with baseline, the mean Functional Assessment of Cancer Therapy-Prostate (FACT-P) score decreased at week 4. A significant polarization of M2-phenotype macrophages and increase in serum and urine levels of M-CSF, HGF, and MIP-1α over baseline were observed at week 12. Baseline serum and urine M-CSF concentrations showed a significant negative correlation with FACT–P scores at weeks 4 and 12.

Conclusions:

The RABBIO study is the first to explore the overexpression of inflammatory proteins in fluid biopsies from patients with symptoms of acute RC. These preliminary findings suggest that serum and urine HGF, M-CSF, MIP-1α, as well as macrophage polarization are potential biomarkers of cystitis after prostate radiotherapy. The elevated M-CSF levels in serum and urine at baseline were associated with the deterioration of QoL during radiotherapy. The results of this study may help to develop mitigation strategies to limit radiation damage to the bladder. Clinical Trial: NCT05246774