Quantitative measures of physical functioning after autologous hematopoietic stem cell transplantation in multiple myeloma: a feasibility study.

BACKGROUND: The safety and feasibility of the symptom-limited cardiopulmonary exercise test (CPET) and the 6-minute walk test (6MWT) has not been rigorously tested in patients with multiple myeloma (MM) after high-dose chemotherapy with autologous stem cell transplantation (ASCT), nor have correlations with patient-reported outcomes (PROs) been explored. PATIENTS AND METHODS: We undertook CPET, 6MWT, and PRO assessments using standardized measurements and questionnaires in patients with MM in remission after ASCT.
RESULTS: A total of 22 patients who were a median of 17 months after ASCT underwent assessment. No severe adverse events were observed. Exercise capacity, measured during CPET as the peak oxygen consumption, was 17.5 ± 5.9 mL/kg/min, the equivalent of 38% ± 18% less than that for age- and sex-predicted sedentary normative values. During the 6MWT, the mean 6-minute walk distance was 500 m, or 25% ± 13% less than the predicted values. Additional analysis using Pearson's correlation revealed no significant univariate associations between exercise or functional capacity and any PROs.
CONCLUSION: Patients with MM have marked and significant reductions in quantitative measures of physical function for years after the initial therapy, although that did not correlate with PROs in the present pilot study. Larger prospective studies are required to determine the clinical ramifications of these findings and to mechanistically dissect them, as well to test interventions aimed at mitigating them.