Effects of Different Radiation Dosimetry for Anorectal Function of Patients With Pelvic Cancer

Inclusion criteria 18-75 years of age. Anal cancer and rectal cancer with pathological diagnosis. Patient will undergo sphincter-preserving therapies. Eastern Cooperative Oncology Group (ECOG) score for performance status is 0-2. Written informed consent. Exclusion criteria Patients who have undergone pelvic surgery, such as rectal cancer surgery and gynaecological procedures. Patients who have received pelvic radiotherapy. Patients with other active malignant tumors. Patients with a history of prior peri-anal abscess, anorectal trauma, and inflammatory bowel disease (IBD). Recently (less than 4 weeks) received surgery or patients with recent severe trauma. Significant cardiac disease: congestive heart failure of New York Heart Association class ≥2; patients with recent (less than 12 months) active coronary artery disease (unstable angina or myocardial infarction). Recent (less than 6 months) thrombosis or embolism events, such as cerebrovascular accident (including transient ischemic attack), pulmonary embolism and deep vein thrombosis. Patients with toxicity (Common Terminology Criteria for Adverse Events (CTCAE) Grade ≥ 2) caused by previous treatment that has not subsided. Women who suffered anal sphincter tear after vaginal delivery. Pregnant or lactating women.