Radiation in Gastroenterology

Abstract

The benefit of radiation is immense in the field of gastroenterology. Radiation is used daily in different gastrointestinal imaging and diagnostic and therapeutic interventional procedures. Radiotherapy is one of the primary modalities of treatment of gastrointestinal malignancies. There are various modalities of radiotherapy. Radiotherapy can injure malignant cells by directly damaging DNA, RNA, proteins, and lipids and indirectly by forming free radicals. External beam radiation, internal beam radiation and radio-isotope therapy are the major ways of delivering radiation to the malignant tissue. Radiation can also cause inflammation, fibrosis, organ dysfunction, and malignancy. Patients with repeated exposure to radiation for diagnostic imaging and therapeutic procedures are at slightly increased risk of malignancy. Gastrointestinal endoscopists performing fluoroscopy-guided procedures are also at increased risk of malignancy and cataract formation. The radiological protection society recommends certain preventive and protective measures to avoid side effects of radiation. Gastrointestinal complications related to radiation therapy for oncologic processes, and exposure risks for patients and health care providers involved in diagnostic or therapeutic imaging will be discussed in this review.

The gut microbiota as a booster for radiotherapy: novel insights into radio-protection and radiation injury

“…Compared to cross-sectional studies, repeated sampling in a longitudinal design has higher statistical power, and some studies associate the microbial dynamics throughout radiotherapy with radio-dosimetry [ 18 – 22 ] and radiation injury [ 17 , 23 – 25 ]. Reportedly, abdominal dose of > 1.5 Gy is a risk factor of RE and the dose threshold for gastrointestinal lining loss is 6 Gy [ 26 ]. The threshold for hematopoietic dysfunction is 0.5 Gy and the exquisitely radio-sensitive lymphocytes are maximally depressed when exposed to radiation of ~ 2 Gy, which is the standard fractionated regimen adopted in the clinic [ 27 ].…”

“…The threshold for hematopoietic dysfunction is 0.5 Gy and the exquisitely radio-sensitive lymphocytes are maximally depressed when exposed to radiation of ~ 2 Gy, which is the standard fractionated regimen adopted in the clinic [ 27 ]. According to historic reports and our clinical experience, patients typically present gastrointestinal symptoms since the first or second week of radiotherapy [ 26 ] and may develop progressive myelosuppression almost immediately within the first week of radiotherapy [ 27 ]. Therefore, timely identification of high-risk population (> 2 Gy absorbed dose) in need of medical intervention is critical both for ensuring safety of radiotherapy in clinical settings and for appropriate allocation of medical resources after accidental nuclear exposure.…”

Concurrent rectal perforation and obstruction following neoadjuvant chemoradiation for locally advanced rectal cancer: A case report

“…Colonic obstruction is another uncommon acute complication of RT injury [ 4 ]. In this case presentation, we detailed the experience a 77-year-old male facing LARC, encountering simultaneous complete bowel obstruction and rectal perforation two months after neoCRT.…”

An in situ self‐assembled peptide derivative for inhibition of glutathione synthesis and selective enhancement of tumor radiotherapy

“…Radiotherapy is one of the most common treatments for killing cancer cells. Ionizing radiation can cause direct breakage of DNA strands and indirect oxidative stress, synergistically imposing damage to DNA, proteins, and lipid [1][2][3]. Approximately two-thirds of cellular injury within radiotherapy is attributed to the oxidative stress caused by excess reactive oxygen species (ROS) [4].…”