Hyperbaric Oxygen Therapy in the treatment of chronic radiation-induced proctitis-is it effective?

Abstract

Background Radiation proctitis (RP) is a relatively frequent (5-20%) type of late secondary lesion following radiotherapy and the most severe cases can have a mortality rate up to almost 10%. Hyperbaric oxygen therapy (HBOT) is a safe and low-risk treatment that not only reduces symptomatology, but also directly affects the pathophysiology of this disease, promoting tissue oxygenation, neovascularization, re-epithelialization, and reversal of the fibroatrophic process induced by ionizing radiation. Currently, the European Committee for Hyperbaric Medicine (ECHM) recommends hyperbaric oxygen therapy for the treatment of RP, with a grade of recommendation I but with a level of evidence B, stating that further studies are needed to verify the level of evidence. The aim of our study was to analyze the effectiveness of HBOT as a complementary treatment for RP. Methods We performed a retrospective cohort study at the single HBOT Unit of the North of Portugal. All patients admitted to HBOT for radiation proctitis between October 2014 and September 2022 were included in the study. Upon attendance and after providing written consent, all patients were interviewed face-to-face, before and after treatment with HBOT, by a trained physician who completed the LENT/SOMA scale (Late Effects Normal Tissues-Subjective, Objective, Management, Analytical scale) regarding the severity of RP symptoms, most specifically the subjective element of this scale. Other radiation-related symptoms and diagnoses were also noted. Patient demographics, referral characteristics, tumor and radiation characteristics, number of sessions of HBOT and repetition of HBOT due to relapse were reviewed. The obtained data was then analyzed using multiple statistical tests. The significance-level considered was 5%. Results After HBOT treatment, 26 patients had a significant reduction (WT p<0.001; median reduction of -3, interquartile range -2 to -5 for overall cohort) in the score of the subjective element (S) of the LENT-SOMA scale, three of them had an increase and one patient remained with the same score as prior to the HBOT treatment. It is also worth noting that five patients had complete resolution of symptomatology, with an S score of 0 after HBOT treatment completion. Older people and females had higher baseline LENT-SOMA scores (rs = -0.493, p=0.007; MWU p=0.005, respectively). The LENT-SOMA difference was related to baseline LENT-SOMA (a greater decrease was found in patients with higher baseline LENT-SOMA, rs= -0.493, p=0.007; p=0.016 after adjustment for age and sex). None of the other demographic, referral, tumor or HBOT characteristics (number of sessions and time from symptom onset to HBOT) affected LENT-SOMA difference. Conclusion With this, it was possible to assess that the majority of the included patients had a significant reduction of the subjective element of the LENT-SOMA scale after completing HBOT treatment, which confirms the significant improvement of their radiation proctitis related symptoms after treatment completion. This reinforces hyperbaric oxygen therapy as an effective complementary therapy in the treatment of refractory radiation lesions.