The incidence of anal cancer continues to rise. People are still reluctant to discuss this important cancer. The majority of patients with this cancer are cured by a combination of treatment of radiation and chemotherapy.

The purpose of this study was to determine whether outcomes are improved with the addition of chemotherapy versus radiation alone for stage I squamous cell carcinoma of the anus.

This was a cohort analysis using Surveillance, Epidemiology and End Results registry linked to Medicare from 1996 to 2011. Propensity-score methods were used to control for potential confounding.

Medicare-eligible patients (age >65 y or with an eligible disability) with stage I squamous cell carcinoma of the anus treated with either definitive radiation alone or chemoradiation were included. Radiation or chemoradiation was the intervention.

However, this treatment can have significant side effects, particularly in the elderly or those in poor general health. In a study featured in the July 2018 issue of the Diseases of the Colon and Rectum, researchers from the Icahn School of Medicine at Mount Sinai in New York City used the Surveillance, Epidemiology and End Results (SEER) Registry.

Chemoradiation versus radiation

It has been linked to Medicare and studied 99 patients with stage I anal cancer who were treated only with radiation therapy and compared these to 200 patients who were treated with the standard combination of chemotherapy and radiation.

After adjusting for patient comorbidities, HIV status, use of home health services, sociodemographic characteristics and other factors, they found that there was no difference in overall-, cause-specific, colostomy-free or disease-free survival. In contrast, chemoradiation was associated with more early and late side effects due to treatment.

The authors concluded that radiation therapy alone might provide for adequate cancer treatment when used to treat older, sicker patients with early-stage anal cancers.

A quote from the first author Michael Buckstein: "This study uses SEER-Medicare to generate the largest series, to our knowledge, of Stage I patients to explore outcomes of chemoradiation versus radiation alone."

Although the benefit of chemoradiation over radiation therapy alone has been shown in randomized trials for stage II to III squamous cell of the anus, this benefit is not clear for patients with stage I cancer.

Nevertheless, most societal recommendations endorse chemoradiation for patients with stage I squamous cell carcinoma of the anus despite the lack of proven benefit and a potential increase in toxicity. Overall survival, disease-free survival, cause-specific survival, colostomy-free survival, and acute or late toxicities were measured.

Lone radiation might be associated with adequate oncologic outcomes when used to treat older and sicker patients with stage I anal cancer. Physicians should discuss the potential benefits and harms of adding chemotherapy for the treatment of these patients.