Anal Canal-Sparing Technique During Postoperative Pelvic Radiation Therapy for Cervical Cancer Patients to Reduce Hemorrhoids-related Symptoms: A Multicenter Randomized Clinical Trial

Radiation therapy (RT) is a main treatment method to improves local control and overall survival for cervical cancer patients with high-risk factors. External beam radiation therapy (EBRT) is particularly important, which plays a crucial role for patients either after surgery or for those ineligible for surgery. In intensity-modulated radiation therapy (IMRT) era, 90-95% of patients with pelvic malignancies, including gynecological tumors, still develop varying degrees of radiation-induced intestinal injury. Radiation-induced rectal injury (RRI) is still one of the most common complications of radiation to the pelvis, but which is also the most difficult to treat.

However, whether from the symptoms or the pelvic radiation therapy plans, current studies on RRI generally combine the rectum and anal canal. Therefore, the so-called "Radiation-induced rectal injury" is not purely "rectal injury," but includes "radiation-induced rectal and anal canal injury." In addition, the radiation of perianal muscles can also lead to symptoms related to the rectum during pelvic radiation therapy. According to current contouring guidelines, whether for gynecologic tumors or other pelvic malignancies, the anal canal is regarded together with the rectum as the same organ at risk (OAR) when formulating pelvic EBRT plans, and a unified dose constraint standard is applied. The anal canal and its surrounding muscles are not assessed separately.

The tolerance dose of the rectum is generally considered to be around 50 Gy, however, anal canal-related symptoms may occur at lower doses, particularly in patients with a history of hemorrhoids. During the early phase of radiotherapy, hemorrhoids-associated symptoms such as perianal pain, hemorrhoidal prolapse, rectal bleeding, and perianal skin breakdown may occur. These symptoms are more likely attributable to the aggravation of pre-existing hemorrhoids rather than radiation-induced rectal injury. Hemorrhoidal disease (HD) is one of the most common gastrointestinal disorder managed in outpatient clinics. Although it is not a life-threatening condition, it can persistently and severely impact quality of life and increase the healthcare burden on society.

Anal canal toxicity should not be a neglected side-effect of pelvic radiation therapy, and greater attention need to be paid to the occurrence of acute hemorrhoid-related symptoms, particularly for cervical cancer patients with hemorrhoids. The investigators tried to develop anal canal-sparing technique to reduce the irradiated dose to anal canal for cervical cancer patients with hemorrhoids who needed postoperative pelvic radiation therapy.

Minimizing acute toxic effects is of considerable importance to improve quality of life because it has been correlated with late toxic effects in patients with pelvic radiation therapy. Herein, the investigators design a multicenter, double-blind randomized controlled trial in which cervical cancer patients with hemorrhoids were randomly assigned to receive anal canal-sparing or standard postoperative pelvic radiation therapy, in either combined with brachytherapy or not.