This invention concerns treating apparently normal tissue surrounding sitesof cancerous tumors so as to reduce both the probability of a recurrence of cancerat and near the site of a cancerous tissue, and to reduce the amount of apparentlyhealthy tissue that is usually excised along with the tumor, thereby providinga substantial benefit to the cancer patient by eliminating or delaying tumorrecurrence and sparing normal tissue for its functionality and for avoidingunnecessary disfigurement.