Randomised single centre double-blind placebo controlled phase II trial of Tocovid SupraBio in combination with pentoxifylline in patients suffering long-term gastrointestinal adverse effects of radiotherapy for pelvic cancer: the PPALM study

Interventions for Managing Late Gastrointestinal Symptoms Following Pelvic Radiotherapy: a Systematic Review and Meta-analysis

AIMS

Pelvic radiotherapy can induce gastrointestinal injury and symptoms, which can affect quality of life. We assessed interventions for managing these symptoms.

MATERIALS AND METHODS

A review of randomised controlled trials published between January 1990 and June 2023 from databases including MEDLINE, EMBASE, CENTRAL, CINAHL, clinicaltrials.gov, ISRCTN and grey literature sources was conducted. Meta-analyses were carried out using the DerSimonian and Laird random effects model to produce overall treatment differences with 95% confidence intervals.

RESULTS

Twenty-eight studies (2392 participants) of varying methodological quality were included. 4% formalin was superior to sucralfate for improving gastrointestinal symptom score (standardised mean difference [SMD] -1.07, 95% confidence interval -1.48 to -0.65). Argon plasma coagulation (APC) was inferior to sucralfate (SMD 1.22, 95% confidence interval 0.84 to 1.59). Counselling positively influenced symptom score (SMD -0.53, 95% confidence interval -0.76 to -0.29), whereas hyperbaric oxygen therapy showed conflicting results. Sucralfate combined with APC increased endoscopic markers of moderate-severe bleeding versus APC alone (risk ratio 2.26, 95% confidence interval 1.12 to 4.55). No definite conclusions on pain, incontinence, diarrhoea, tenesmus or quality of life interventions were confirmed.

CONCLUSIONS

Small study sizes, methodological quality and heterogeneity limit support of any individual intervention. APC and 4% formalin seem to be promising interventions, with further larger randomised controlled trials now warranted.

Parsimonious Effect of Pentoxifylline on Angiogenesis: A Novel Pentoxifylline-Biased Adenosine G Protein-Coupled Receptor Signaling Platform

Angiogenesis is the physiological process of developing new blood vessels to facilitate the delivery of oxygen and nutrients to meet the functional demands of growing tissues. It also plays a vital role in the development of neoplastic disorders. Pentoxifylline (PTX) is a vasoactive synthetic methyl xanthine derivative used for decades to manage chronic occlusive vascular disorders. Recently, it has been proposed that PTX might have an inhibitory effect on the angiogenesis process. Here, we reviewed the modulatory effects of PTX on angiogenesis and its potential benefits in the clinical setting. Twenty-two studies met the inclusion and exclusion criteria. While sixteen studies demonstrated that pentoxifylline had an antiangiogenic effect, four suggested it had a proangiogenic effect, and two other studies showed it did not affect angiogenesis. All studies were either in vivo animal studies or in vitro animal and human cell models. Our findings suggest that pentoxifylline may affect the angiogenic process in experimental models. However, there is insufficient evidence to establish its role as an anti-angiogenesis agent in the clinical setting. These gaps in our knowledge regarding how pentoxifylline is implicated in host-biased metabolically taxing angiogenic switch may be via its adenosine A2BAR G protein-coupled receptor (GPCR) mechanism. GPCR receptors reinforce the importance of research to understand the mechanistic action of these drugs on the body as promising metabolic candidates. The specific mechanisms and details of the effects of pentoxifylline on host metabolism and energy homeostasis remain to be elucidated.

Radioprotective countermeasures for radiation injury (Review)

A series of physiological and pathological changes occur after radiotherapy and accidental exposure to ionizing radiation (IR). These changes cause serious damage to human tissues and can lead to death. Radioprotective countermeasures are radioprotective agents that prevent and reduce IR injury or have therapeutic effects. Based on a good understanding of radiobiology, a number of protective agents have achieved positive results in early clinical trials. The present review grouped known radioprotective agents according to biochemical categories and potential clinical use, and reviewed radiation countermeasures, i.e., radioprotectors, radiation mitigators and radiotherapeutic agents, with an emphasis on their current status and research progress. The aim of the present review is to facilitate the selection and application of suitable radioprotectors for clinicians and researchers, to prevent or reduce IR injury.

The Self-Administered Use of Complementary and Alternative Medicine (CAM) Supplements and Antioxidants in Cancer Therapy and the Critical Role of Nrf-2-A Systematic Review

Complementary and alternative medicine (CAM) supplements are widely used by cancer patients. Dietary supplements, vitamins and minerals, herbal remedies, and antioxidants are especially popular. In a systematic literature review, 37 studies, each including more than 1000 participants, on CAM, dietary supplement, and vitamin use among cancer patients were identified. Accordingly, cancer patients use antioxidants such as vitamin C (from 2.6% (United Kingdom) to 41.6% (United States)) and vitamin E (from 2.9% (China) to 48% (United States)). Dietary supplements and vitamins are taken for different reasons, but often during conventional cancer treatment involving chemotherapy or radiotherapy and in a self-decided manner without seeking medical advice from healthcare professionals. Drug-drug interactions with dietary supplements or vitamins involving multiple signaling pathways are well described. Since most of the anticancer drugs generate reactive oxygen species (ROS), an adaptive stress response of healthy and malignant cells, mainly driven by the Nrf-2-Keap I network, can be observed. On the one hand, healthy cells should be protected from ROS-overproducing chemotherapy and radiotherapy; on the other hand, ROS production in cancer cells is a "desirable side effect" during anticancer drug treatment. We here describe the paradoxical use of antioxidants and supplements during cancer therapy, possible interactions with anticancer drugs, and the involvement of the Nrf-2 transcription factor.

Vitamin E in Cancer Treatment: A Review of Clinical Applications in Randomized Control Trials

Vitamin E, along with other vitamins and micronutrients play a range of physiologic roles in the homeostasis of the body. Moreover, they also have postulated therapeutic roles that are often incompletely studied and understood. In this scoping review, we explored the recent randomized control trials (RCTs) of Vitamin E in the context of cancer, to investigate whether Vitamin E has a therapeutic role. We searched major bibliographic electronic databases to identify sixteen RCTs studying the role of Vitamin E in cancer management that have been published in the last ten years. These studies had different methodological qualities, including some that used Vitamin E in combination with other treatments. Furthermore, due to the heterogenous results, it is difficult to make a consensus statement on the effectiveness of Vitamin E in cancer therapeutics. In some cases, there were even suggestion of detriment with Vitamin E supplementation. Therefore, well designed, large, prospective RCTs are needed studying pure isoforms of Vitamin E to establish the safety and efficacy of this dietary supplement.

Impact of radiation therapy on healthy tissues

Radiation therapy has a fundamental role in the management of cancers. However, despite a constant improvement in radiotherapy techniques, the issue of radiation-induced side effects remains clinically relevant. Mechanisms of acute toxicity and late fibrosis are therefore important topics for translational research to improve the quality of life of patients treated with ionizing radiations. Tissue changes observed after radiotherapy are consequences of complex pathophysiology, involving macrophage activation, cytokine cascade, fibrotic changes, vascularization disorders, hypoxia, tissue destruction and subsequent chronic wound healing. Moreover, numerous data show the impact of these changes in the irradiated stroma on the oncogenic process, with interplays between tumor radiation response and pathways involved in the fibrotic process. The mechanisms of radiation-induced normal tissue inflammation are reviewed, with a focus on the impact of the inflammatory process on the onset of treatment-related toxicities and the oncogenic process. Possible targets for pharmacomodulation are also discussed.