Radiation-induced damage of the upper gastrointestinal (GI) tract results from radiation of GI tumors or structures adjacent to the GI tract. Radiation-induced damages of the upper GI tract may be acute or delayed, and ranges from lack of appetite, mucosal inflammation (i.e. esophagitis, gastritis, duodenitis) to ulcers, which may be complicated by perforation, penetration, bleeding and stenosis. Radiation-related factors as well as individual patient predisposing factors may increase susceptibility to post-radiation damage. High quality evidence for the treatment of radiation-induced GI damage is scarce and the management is often extrapolated from studies on GI lesions of different etiology. Treatment depends on severity and localization of the radiation-induced damage, and ranges from supportive and dietary measures to endoscopic interventions or surgery. Modern radiation techniques may decrease the incidence and severity of the radiation-induced upper gastrointestinal disease.Treatment-related acute gastrointestinal toxicities are a common and often debilitating hurdle encountered in the treatment of cancer patients. While the introduction of targeted therapies such as tyrosine kinase inhibitors has led to improvements in survival outcomes, their use has also been complicated by a high frequency of clinically important adverse effects. Selleckchem EGFR inhibitor Gastrointestinal toxicities such as nausea, vomiting, diarrhoea and hepatotoxicity represent potentially serious adverse events that may necessitate dose reductions, treatment interruptions and cessation of treatment. An improved knowledge of the incidence, pathophysiology, management and prophylaxis of these toxicities is crucial in order to reduce patient morbidity and mortality. In this review, we discuss the main gastrointestinal toxicities associated with chemotherapy and targeted therapies in oncology, outlining their incidence, pathophysiology and expert management guidelines.Gastrointestinal microbiota is vastly deregulated in cancer patients due to different factors, but the exact mechanisms of interaction between cancer and microbiome are still poorly understood. Current evidence suggests that alterations in the composition of the microbiota may affect efficacy and toxicity of anti-cancer therapies. Recent preclinical and clinical studies demonstrate different mechanisms and outcomes of deregulation of gut microbiome, and investigate effects of modulating gastrointestinal microbiota in cancer patients. This paper reviews effects of altered microbiome on anti-cancer management, including antibiotics, chemotherapy and immunotherapy, as well as possible outcomes of modulating altered microbiome by probiotics or faecal microbiome transplantation in cancer patients.Malnutrition and the broad spectrum of cancer cachexia frequently occur in patients with malignant disease of all tumour stages and impact on survival and quality of life of patients. Structured screening for the risk of malnutrition with validated tools and nutritional assessment are the prerequisite for adequate nutritional support in cancer patients. In patients receiving tumour directed therapy, the patients diet should meet the requirements to give optimal support, while later on comfort feeding is part of symptom focused palliation. The basis of nutritional support in a malnourished patient is nutritional counselling, and nutritional support can be offered within a step-up approach meeting the patient’s needs. A combination of nutritional support with interventions targeting metabolic changes and physical exercise is suggested to treat cancer cachexia.In this chapter, we describe the gastrointestinal side effects of oesophagectomy, gastrectomy and pancreaticoduodenectomy for cancer, with a focus on long-term functional impairments and their management. Improvements in upper gastrointestinal cancer surgery have led to a growing group of long-term survivors. The invasive nature of these surgeries profoundly alters the upper gastrointestinal anatomy, with lasting implications for long-term function, and how these impairments may be treated. Successfully maintaining a high quality of survivorship requires multidisciplinary approach, with survivorship care plans focused on function as much as the detection of recurrence.Cancer survival is improving rapidly due to advances in treatments that will often involve radiotherapy, chemotherapy and novel biological agents in addition to surgery. This comes at the price of living with chronic symptoms, of which diarrhoea is particularly common. There is good evidence that for many patients these symptoms become part of everyday life, their “normality” is adjusted and symptoms are tolerated even when limiting activities severely. Clinicians often fail to appreciate the impact of these problems, as the focus of follow up tends to be on cancer recurrence. However, the rapid identification of patients in significant trouble can lead to earlier diagnosis of treatable pathologies and improvement of patients’ symptoms. The aim of this review is to highlight the mechanisms which cause oncology patients to develop diarrhoea and highlight useful investigational and treatment strategies.Hepatic tumors include hepatocellular cancer (HCC) and cholangiocarcinoma (CC), a small subgroup of tumors (approx. 1%) are classified as combined hepatocellularcholangiocellular carcinomas. Different stage-dependent therapeutic approaches comprise resection, local ablative techniques, locoregional therapies, systemic treatment, liver transplantation in selected cases and possible combination of these treatment modalities. This review summarizes current knowledge on multi-modal treatment strategies for liver cancer focusing on gastrointestinal side effects.Radiation therapy is an important ally when treating malignant lesions in the pelvic area, but it is not exempt of adverse events. There are some measures that can be taken to reduce the possibility of these effects, but some are non-modifiable factors related to previous treatments, location of the lesions or comorbidities. There is a wide variety of clinical presentations that can be of an acute or chronic onset that go from mild to severe forms or that can have a great impact in the quality of life. Medical available therapies as metronidazole, sucralfate, mesalizine or probiotics, can be of aid although some lack of solid evidence of efficacy. Endoscopic treatment can be performed with argon plasma coagulation, bipolar cautery, radiofrequency, laser therapy or dilation. Hyperbaric therapy can be applied in refractory cases and surgery must be reserved to selected patients due to its high morbidity and mortality.