Gastrointestinal cancer

Abstract

Many cancers of the gastrointestinal tract are treated with chemotherapy, radiation, and surgery. Chemotherapy is often used as a radiation sensitizer amplifying both the therapeutic effect and the toxicity of radiation. Since anal and rectal cancer treatment may require radiation to the perianal skin, this chapter focuses on these two disease entities and the management of associated skin toxicity. Nonetheless, these methods can be extended to other sites in the management of gastrointestinal malignancies where skin reactions may occur. Chemoradiation for anal cancer may involve the use of 5-fluorouracil (5-FU) and mitomycin C (MMC), a regimen, when used in combination with radiation therapy, is known to cause skin toxicity. In addition, HIV-positive patients with anal cancer require special attention. Those with low CD4 counts have an increased risk of skin toxicity, infection, and poor healing. Radiation therapy alone, or with weekly chemotherapy, can be considered for these patients, depending on their comorbidities. Rectal cancer patients also undergo chemoradiation, but several factors contribute to lower toxicity in these patients compared to anal cancer patients: (1) chemotherapy is single-agent 5-FU, (2) the radiation dose is lower since patients will be getting surgery after to remove the tumor, and (3) due to the location within the deep pelvis, radiation fields do not typically extend to the skin. Nonetheless, these patients can also exhibit skin toxicities, and management of these toxicities is similar. For the management of skin toxicity in anal and rectal cancer patients undergoing radiation, planning for skin toxicity must be incorporated into treatment. We recommend examining the skin dose closely and placing film dosimeters at first treatment, managing gastrointestinal toxicity as diarrhea can cause irritation of skin, and providing patients with a nutrition consult prior to therapy.