Topical chemotherapy. Chemotherapy refers to the treatment of conditions with drugs, and often is applied to the use of anti-cancer agents (but may also be applied to others). Topical means that it is applied directly to the lesion in question and is not taken systemically (by mouth or injection) and meant to get the lesion through the blood stream. Hope this is clear. Good luck.
5-FU for skin cancer. The most common cancers are skin cancers which are best prevented by topical treatment of precursor lesions (actinic keratoses) using 5-fluorouracil (5-fu). Early stage squamous cell cancers are also treated the same way. Anal papillomas are managed topically with podophyllin, trichloroacetic acid, or 5-fu. Rx when anal warts become malignant may be surgical or topical with these same agents.