Intensity-modulated radiation therapy improves tumor response in anal cancer

This study investigated tumor response and safety of intensity-modulated radiation therapy (IMRT) in anal cancer. Researchers reported an excellent response result and low short-term side effects for IMRT in these patients.

Colorectal cancer is one of the most common cancers worldwide. Anal cancer is a rare form of CRC and affects 8590 adults every year in the US. The anus is the opening at the end of the digestive system, where stool leaves the body.

The primary treatment used to be surgery. Chemotherapy and radiation therapy have replaced the need for surgery as first-line treatment. However, this comes with a higher rate of side effects. This is true, especially if high doses of radiation are applied.

IMRT is a type of radiotherapy where the intensity is controlled in a way that it only affects the tumor. This way healthy tissues/organs are preserved. IMRT also allows boost treatments that involve the application of different radiation doses to different targets. Based on this, it has been suggested that IMRT should be the primary option to treat anal cancer. However, too little is known about the early and late side effects associated with IMRT in patients with anal cancer.

This study included information about 84 patients with anal cancer. All patients were treated with IMRT. Patients were followed-up at the end of therapy, every 4 months for the first 2 years and every 6 months up to 5 years.

All 84 patients experienced immediate side effects (from the end of IMRT to 6 months). Severe gastrointestinal side effects were seen in 4 patients (5%) and skin side effects in 19 (23%).

Early-late side effects (from 6 months after IMRT to 1 year) were seen in 73 patients (87%). Severe gastrointestinal side effects (3%) and vaginal side effects (3%) were observed in this group. 65 patients (77%) stopped treatment.

Colostomy-free survival was 96% at 6 months and 92% at 12 months. A colostomy is a surgical procedure that brings the end of the bowel to the abdomen into a special bag that collects waste. This can be permanent or temporary.

At 6 months complete response was observed in 70 patients (83%) and partial response in 3 (4%). Disease progression was observed in 7 patients (8%). At 12 months complete response was observed in 60 patients (81%) and 11 patients (15%) experienced disease progression.

This study concluded that IMRT is a good and safe treatment option for patients with anal cancer.

This study was based on medical records. Some information might have been incomplete. This might affect the results. Also, this study only reported the outcomes up to 12 months. Long-term results will be reported in a subsequent study.