Supersaturated Calcium Phosphate Rinse in Preventing Oral Mucositis in Young Patients Undergoing Autologous or Donor Stem Cell Transplant

PRIMARY OBJECTIVES: I. To determine if topically administered supersaturated calcium phosphate (Caphosol), rinsed orally four times daily at the initiation of conditioning for hematopoietic stem cell transplantation (HSCT), reduces oral mucositis as demonstrated by a decrease in duration of severe oral mucositis (World Health Organization \[WHO\] grade 3 or 4), compared to placebo. SECONDARY OBJECTIVES: I. To determine whether Caphosol administration, when compared to placebo, reduces oral mucositis as demonstrated by a decrease in incidence of severe oral mucositis (WHO grade 3 or 4); severity of mucositis according to mouth pain categorical rating scale and Oral Mucositis Daily Questionnaire (OMDQ); incidence, total dose, and duration of parenteral opioid analgesic use (morphine equivalents); and incidence and duration of total parenteral nutrition (TPN) administration. II. To determine whether Caphosol administration, when compared to placebo, reduces the incidence of febrile neutropenia and invasive bacterial infections. III. To validate a new pediatric measure of oral mucositis termed the Children's International Mucositis Evaluation Scale (ChIMES). OUTLINE: This is a multicenter study. Patients are stratified according to conditioning regimen (total-body irradiation (TBI) or melphalan vs neither TBI nor melphalan) and hematopoietic stem cell transplantation (HSCT) (autologous vs allogeneic). Patients are randomized to 1 of 2 treatment arms. ARM I: Patients rinse and gargle with supersaturated calcium phosphate rinse over 1 minute four\* times daily (QID) beginning on the first day (about day -7) of the conditioning regimen. ARM II: Patients rinse and gargle with placebo over 1 minute QID\* beginning the first day (about day -7) of the conditioning regimen. NOTE: \* Patients who reach WHO grade 3 or 4 mucositis have the option to request a total of 6 rinses daily. In both arms, treatment continues until day 20 post-transplantation OR until mucositis resolves to WHO grade =\< 2 for two consecutive days OR on day 12 in patients who do not experience oral mucositis of at least WHO grade \>= 1. Patients are assessed daily by trained healthcare professionals using the Oral Mucositis Daily Questionnaire (OMDQ), the Pain Rating Scale, the WHO Mucositis Scale, and the Children's International Mucositis Evaluation Scale (ChIMES) from day -1 and continuing until day 20. Patients are also observed for the incidence of total dose and duration of parenteral opioid analgesic use, duration of total parenteral nutrition (TPN) administration, febrile neutropenia, and invasive bacterial infections. After completion of study therapy, patients are followed up for 30 days.