Toll-like receptor 4 signaling: a common biological mechanism of regimen-related toxicities: an emerging hypothesis for neuropathy and gastrointestinal toxicity.
BACKGROUND The percentage of people living with a diagnosis of cancer is rising globally. Between 20% and 25% of people treated for cancer experience a consequence of cancer which has an adverse impact on the quality of their life. Gastrointestinal (GI) symptoms are the most common of all consequences of cancer treatment and have the greatest impact on daily activity. PATHOPHYSIOLOGY OF LONG-TERM BOWEL DAMAGE AFTER PELVIC RADIOTHERAPY: Long-term damage to the bowel after radiotherapy is mediated by ischaemic changes and fibrosis. Each fraction of radiotherapy causes a series of repetitive injuries to the intestinal tissue resulting in an altered healing process, which affects the integrity of the repair and changes the architecture of the bowel wall. THE NATURE OF GI SYMPTOMS THAT DEVELOP: Patient-reported outcome measures show that diarrhoea, urgency, increased bowel frequency, tenesmus and flatulence are the five most prevalent GI symptoms with a moderate or severe impact on patients' daily lives after treatment with pelvic radiotherapy. Many patients also experience fatigue, urinary problems and have sexual concerns. SYSTEMATIC ASSESSMENT AND MANAGEMENT: The complex nature of those symptoms warrants systematic assessment and management. The use of a tested algorithm can assist in achieving this. The most common contributing factors to ongoing bowel problems after pelvic radiotherapy are small intestinal bacterial overgrowth, bile acid malabsorption, pancreatic insufficiency, rectal bleeding and its impact on bone health. THE WIDER CONTEXT Symptom burden, socio-psychosocial impact, memory and cognitive function, fatigue, urinary problems and sexual concerns need to be taken into account when thinking about consequences of cancer treatment. CONCLUSION As our understanding of consequences of cancer treatments continues to emerge and encompass a wide variety of specialties, a holistic, multifaceted and multidisciplinary approach is required to manage those consequences long-term.