History of calcium oxalate stones No more than grade abnormalities of potassium, calcium (confirmed by ionized calcium), magnesium, and phosphorus (supplementation allowed) Calcium >= LLN Serum calcium within normal institutional limits Calcium within normal range (supplementation is allowed) Patients with contraindication to use leucovorin calcium (calcium folinate), -fluorouracil, and oxaliplatin (FOLFOX) chemotherapy and pelvic radiation. Total serum calcium (corrected for serum albumin) or ionized calcium >= lower limit of normal (LLN) Calcium WNL Demonstrate adequate organ function as defined in protocol, AND normal (WNL of local lab range) serum correct calcium, and phosphorus levels. Serum calcium, magnesium, and phosphorous with institutional normal limits (supplementation is permissible) Serum calcium & phosphorus within normal institutional limits Total calcium (corrected for serum albumin) >= LLN or correctable with supplements prior to first dose of study medication Use of medications that increase serum levels of phosphorus and/or calcium Total and ionized serum calcium outside of normal limits Use of medications that increase serum levels of phosphorus and/or calcium (e.g., calcium, phosphate, vitamin D, parathyroid hormone) Serum calcium >= LLN Serum calcium >= LLN Normal ionized calcium (can be on oral supplementation) Within days prior to registration: Total serum calcium (corrected for serum albumin as needed) or ionized calcium within institutions normal range Normal ionized calcium, magnesium and phosphorus (can be on oral supplementation) Serum calcium or magnesium outside the institutional range of normal Serum calcium within normal limits Calcium >= LLN Current treatment with intravenous bisphosphonate or denosumab with elevated serum calcium corrected for albumin or ionized calcium levels outside institutional normal limits at screening Serum calcium levels outside the laboratorys reference range Adjusted (or ionized) calcium >= the institutional lower limit of normal (supplementation of electrolytes prior to screening is allowed) Currently on bisphosphonate or denosumab with elevated serum calcium levels corrected for albumin/ionized calcium levels outside of institutional normal limits History of a calcium/phosphate homeostasis disorder Patient has serum potassium and magnesium levels WNL for the institution and total serum calcium or ionized calcium levels ? the lower limit of normal (LLN). Patients with low potassium, calcium, and/or magnesium levels may receive supplementation to meet the protocol entry criteria. (Calcium supplementation is prohibited after starting PBI-; see Appendix .) Electrolytes (including potassium, sodium, and serum calcium corrected for albumin or ionized calcium) must be within normal limits Electrolytes (including potassium, sodium, and serum calcium corrected for albumin or ionized calcium) must be within normal limits Subjects with a history of calcium oxalate nephrolithiasis are excluded Participants with a serum potassium less than . mmol/L or a serum ionized calcium or magnesium below the lower limits of normal (or above CTCAE grade upper limit); correction of these electrolyte abnormalities with supplements is allowed (serum calcium above the CTCAE grade upper limit; in cases where the serum calcium is below the normal range, the calcium adjusted for albumin is to be obtained and substituted for the measured serum value; exclusion is to then be based on the calcium adjusted for albumin values falling below the normal limit) Calcium (after correction for albumin level) > LLN or correctable with supplements Plasma calcium > . and < . Total serum calcium [corrected for serum albumin] or ionized calcium >= LLN Calcium >= LLN Patients with normal level of serum ionized calcium and phosphate. Total serum calcium (corrected for serum albumin) or ionized calcium >= LLN Total serum calcium (corrected for serum albumin) or ionized calcium >= LLN Total serum calcium (corrected for serum albumin) or ionized calcium below ULN Normal serum calcium (or normal corrected serum calcium) Total serum calcium or ionized calcium level >= institutional lower limit of normal Current treatment with intravenous bisphosphonate or denosumab with elevated serum calcium corrected for albumin or ionized calcium levels outside institutional normal limits at screening Serum potassium and magnesium levels within institutional normal limits. Total serum calcium or ionized calcium level must be greater than or equal to the lower limit of normal. Serum calcium (ionized or corrected for albumin) ? . mmol/L (. mg/dL or . mmol/L ionized calcium) to ? . x ULN. RECURRENT/ PROGRESSIVE DIPG (STRATUM ): Serum total calcium (correct for serum albumin) or ionized calcium >= LLN NON-PROGRESSED DIPG (STRATUM ): Serum total calcium (correct for serum albumin) or ionized calcium >= LLN Total serum calcium (corrected for serum albumin) or ionized calcium >= LLN Calcium: not above normal institutional limit Unwillingness to stop calcium supplementation Serum calcium > .; electrolyte repletion is allowed to reach these values Use of medications that increase serum levels of phosphorus and/or calcium Total and ionized serum calcium outside of normal limits Total serum calcium [corrected for serum albumin] or ionized calcium >= LLN Serum calcium >=Grade (per CTCAE v.) at time of enrolment, unless ionized calcium is within normal range Serum total calcium (corrected for serum albumin) or serum ionized calcium >= LLN Corrected serum calcium concentration within normal range per local clinical laboratory standard Calcium phosphorus product less than .mmol/L. Ionized calcium =< ULN Preoperative parathyroid hormone (PTH) elevated beyond normal range or inappropriately high for associated calcium level Subjects with any pathology associated with altered serum calcium levels If taking more than mg/day of elemental calcium, must be willing and able to discontinue or reduce their calcium use and/or use non-calcium based therapies for the duration of the study Has history of calcium oxalate stones History of known abnormalities in calcium metabolism Serum calcium =< institutional ULN Acute liver disease, unexplained transaminase elevations, or elevated serum calcium Serum calcium above the CTCAE grade upper limit; in cases where the serum calcium is below the normal range, options would be available: ) the calcium adjusted for albumin is to be obtained and substituted for the measured serum value; exclusion is to then be based on the adjusted for albumin values falling below the normal limit; ) determine the ionized calcium levels; if these ionized calcium levels are out of normal range despite supplementation, then the patient must be excluded History of known abnormalities in calcium metabolism Has serum calcium less than or equal to ULN (for patients with an albumin lower than ., a corrected calcium serum calcium = serum calcium +[.][.-serum albumin]) within hours prior to registration Patients receiving calcium-lowering therapy or drugs that may affect calcium levels (e.g., calcitonin, mithramycin, phosphate, denosumab) within weeks of initiation of topical calcitriol. Patients who have been managed with bisphosphonates or calcium-lowering therapy for months or greater prior to the start of the trial and have demonstrated evidence for stability of calcium metabolism would be considered eligible for participation in the trial. Patients treated with medications that are known to affect calcium levels within weeks of initiation of topical therapy (> IU vitamin A, calcium supplements, fluoride, antiepileptics).with the exception of subjects on stable therapy for more than six months Participants must have an ionized serum calcium within normal limits Patients with hypercalcemia (using ionized calcium) Serum magnesium and corrected serum calcium within the institutions normal reference range