Post-loading radiotherapy is one of the very important means for cavity tumors such as cervical cancer, esophageal cancer, etc. The clinical effect is certain, but there may be hazards such as radiation cystitis, radiation proctitis, cervical or uterine perforation and so on. 1. Radioactive cystitis: the bladder is located in front of the cervix, and the rear-loaded radiotherapy is internal radiotherapy, and the local radiotherapy dose to the cervix is high, so the bladder located in front of the cervix will inevitably be affected by radiotherapy, and there may be the side-effects and hazards of radioactive cystitis such as frequent urination, urinary urgency, dysuria, hematuria, and so on. 2. Radioactive proctitis: the rectum is located at the back of the cervix, and will inevitably be affected by the rear mounted radiotherapy, which can lead to blood in the stool, urgency and heaviness, and other side effects and hazards of radioactive proctitis. 3. Perforation of the cervix or uterus: Post-loading radiotherapy is to place the applicator near the cervical lesion for irradiation, and the vagina, cervix and part of the uterus are exposed to a higher dose of irradiation, which may lead to perforation of the cervix or uterus when the dose is too high, resulting in abdominal pain, vaginal bleeding, and other side effects and hazards. Rear-loaded radiotherapy may also lead to other discomforts such as drop in white blood cells and fatigue. It is recommended to consult a radiotherapy specialist in a regular hospital to standardize treatment and reduce the incidence of related harm.