Prognostic factors for squamous cell cancer of the anal canal.

Radiotherapy with concurrent chemotherapy is the standard of care for patients with nonmetastatic squamous cell anal cancer. Most patients treated with chemoradiotherapy have an excellent prognosis. However, some heterogeneity exists among anal cancer patients in their outcomes. This article reviews some of the clinical factors, treatment-related factors, and biologic factors that affect outcomes in patients with squamous cell anal cancer. The most important prognostic factors are the T and N stages. Some studies have suggested that women have better prognosis than men. Histologic subtypes and grade do not have a clear prognostic role. Response to treatment and duration of radiotherapy are likely to be important prognostic factors. Some molecular markers such as p53, p21, and cyclin A expression may have prognostic significance, but their role needs to be studied further. A better knowledge of prognostic factors could help us develop individualized therapies for patients and select high-risk patients for more aggressive and innovative treatments. A better understanding of molecular biology is required to characterize the inherent heterogeneity of anal cancer and thereby develop optimal therapies.