A treatment regimen for a patient undergoing fractionated radiation therapy for a solid tumor type cancer to attain an improvement in one or more of and an optimized balancing of cancer cell radiation sensitization, normal cell radioprotection, selective post-exposure inhibition of cancer cell recovery relative to normal cell recovery, and stabilization of body weight during radiation treatment. The regimen comprises administration of a therapeutic amount of genistein to a patient diagnosed with a solid tumor type cancer throughout an administration period that commences at least five days prior to commencement of fractionated cancer radiation therapy and extends until at least the conclusion of fractionated cancer radiation therapy.
