The Role of Radiation Therapy With 5-Fluorouracil in Anal Cancer.
The most commonly used initial treatment of primary epidermoid cancer of the anal canal is radiation combined with concurrent 5-fluorouracil (5-FU) and mitomycin. Randomized trials have shown that these drugs, when combined with split-course or moderate-dose radiation, are superior to the same doses of radiation delivered without drugs. In another trial, the addition of mitomycin to 5-FU resulted in a better outcome thand when 5-FU alone was combined with radiation. Studies are in progress to evaluate treatment with radiation plus 5-FU and cisplatin; this combination has also produced high rates of tumor response in preliminary studies. The optimal schedules and doses of 5-FU to combine with radiation are not known-common usage favors 96- or 120-hour infustions of 5-FU at a dose of 750 to 1,000 mg/m(2)/24 hours, generally administered as one or two courses concurrently with conventional once-daily fractionated radiation. It is unclear whether 5-FU in these combinations is acting as a cytotoxic agent, a radiosensitizer, or both. Despite these uncertainties, empiric clinical studies have led to the development of effective treatment regimens that allow conservation of anorectal function in the majority of patients with anal cancer.
Cummings
BJ
Department of Radiation Oncology, Princess Margaret Hospital, Toronto, ON, Canada