Source:http://linkedlifedata.com/resource/umls/id/C0376495
MSH: The therapy of the same disease in a patient, with the same agent or procedure repeated after initial treatment, or with an additional or alternate measure or follow-up. It does not include therapy which requires more than one administration of a therapeutic agent or regimen. Retreatment is often used with reference to a different modality when the original one was inadequate, harmful, or unsuccessful.,NCI: The repeated act of the dispensing, applying, or tendering of something to another after an initial treatment.