Gastrointestinal Stromal Tumor (GIST)
Anal cancer accounts for 1.6% of all GI malignancies in the US. Its incidence increases with age; the peak is in the sixth and seventh decades. HPV has been liked to this disease, as has renal transplant, smokers, and patients with HIV infection. Symptoms include pain, mass, constipation, diarrhea, and itching, however 25% of cases are asymptomatic. Procedures for diagnosis include physical exam, anoscopy, proctoscopy, and transrectal ultrasound. A biopsy is required. Staging includes imaging. Women should have a gynecologic exam screening for HPV. Both men and women should be checked for HIV.
Treatment can include surgery, combined chemotherapy and radiation or chemotherapy alone. Chemotherapy agents used include 5-FU, mitomycin, and cisplatin.