RESULTS

Patient characteristics

Patient characteristics including age, gender, weight, height, body surface area (BSA), and length of hospital stay are summarized in Table 1. The patients’ age in this study was consistent with common age groups at the diagnosis of each cancer type, such as younger patients diagnosed with ALL and older patients diagnosed with osteosarcoma. The median weight, height, and BSA were appropriate for the patient’s age in all disease types. Males were more prominent than females at a ratio of 2:1. Of the 165 HD-MTX-containing chemotherapy regimens during the study period at our institution, the most common cancer-specific HD-MTX regimen was the osteosarcoma regimen followed by ALL and NHL regimens.

Intravenous hydration was given during each cancer-specific HD-MTX course, as shown in Table 2. The intravenous hydration administrations were grouped as <3,000 and ≥3,000 mL/m2/day. Although the number of intravenous hydrations ≥3,000 mL/m2/day given was less than hydrations <3,000 mL/m2/day, none of the patients in both groups developed clinical signs or symptoms of volume overload from aggressive hydration.

The correlation between plasma methotrexate level at 72 hours and associated factors in cancer-specific HD-MTX regimens

The correlation between 72-hour plasma methotrexate levels and associated factors in disease-specific HD-MTX regimens was analyzed and is shown in Table 3. Of 56 courses of HD-MTX regimen for ALL, elevated 72-hour plasma methotrexate level of ≥0.1 μmol/L was noted in one course of treatment. However, this abnormally elevated methotrexate level was not significantly associated with any factors including patients’ gender, intravenous hydration, HCO3, urine specific gravity, and duration of methotrexate infusion. Adverse complications including mucositis, bone marrow suppression, and liver toxicity were found in 5, 5, and 1 course of HD-MTX treatment, respectively.

(To view a larger version of Table 3, click here.)

Of 34 courses of HD-MTX regimen for NHL, 14 courses were given with intravenous hydrations <3,000 mL/m2/day and the 20 remaining courses were given with intravenous hydrations ≥3,000 mL/m2/day. Four of 14 courses were given at <3,000 mL/m2/day hydration, and seven of 20 courses were given at ≥3,000 mL/m2/day hydration and were associated with an elevated 72-hour plasma methotrexate level of ≥0.1 μmol/L; however, the above association between different intravenous hydrations and 72-hour plasma methotrexate levels was not statistically significant. In addition, the correlation between 72-hour plasma methotrexate levels and other associated factors including patients’ gender, HCO3, urine specific gravity, and duration of methotrexate infusion was analyzed and revealed no statistical significance. Of note, adverse complications were found more in courses having elevated 72-hour plasma methotrexate levels ≥0.1 μmol/L (mucositis [45.5%], bone marrow suppression [27.3%], renal toxicity [9.1%], and liver toxicity [9.1%]) than courses having 72-hour plasma methotrexate levels <0.1 μmol/L (mucositis [13.0%], bone marrow suppression [13.0%], renal toxicity [0%], and liver toxicity [4.3%]).