Light-Emitting Diode Therapy in Preventing Mucositis in Children Receiving Chemotherapy With or Without Radiation Therapy Before Bone Marrow Transplantation

DISEASE CHARACTERISTICS: * Patients undergoing a myeloablative conditioning regimen comprising chemotherapy with or without radiotherapy prior to a first allogeneic bone marrow transplantation PATIENT CHARACTERISTICS: Age: * 2 to 18 Performance status: * Not specified Life expectancy: * Not specified Hematopoietic: * Not specified Hepatic: * Not specified Renal: * Not specified Pulmonary: * No pulmonary dysfunction that would increase significantly the risk of requiring intubation during the first 21 days after transplantation Other: * Not pregnant * Negative pregnancy test * Fertile patients must use effective contraception * No photophobia * Must have emotional, cognitive, and mental maturity sufficient to tolerate light-emitting diode therapy application and oral examination without combativeness PRIOR CONCURRENT THERAPY: Biologic therapy: * See Disease Characteristics Chemotherapy: * See Disease Characteristics Endocrine therapy: * Not specified Radiotherapy: * See Disease Characteristics Surgery: * Not specified Other: * No concurrent medication that may cause epidermal or ocular photosensitivity