Measured Versus Self Reported Physical Function In Adult Survivors Of Childhood Cancer

Abstract

Background: There are over 320,000 survivors of childhood cancer in the United States. Many of these survivors have chronic disease (69%) that may impact physical performance. PURPOSE: The purpose of this study was to evaluate how well self reported physical performance among childhood cancer survivors compares to physical performance measured with objective testing. METHODS: This investigation included members of the St. Jude Children's Research Hospital Lifetime Cohort, a study designed to evaluate health status among adult survivors of childhood cancer treated between 1962 and 1999 when younger than 21 years of age. Participants reported performance using the physical function subscale of the Medical Outcomes Survey Short Form 36 (SF-36). Physical performance was measured by having participants complete the physical performance test (PPT), and the six minute walk (6MW). RESULTS: 496 cancer survivors (276 women, 220 men, and median age 35 years) completed the questionnaire and the physical assessment. Primary cancer diagnoses included 275 leukemias, 104 lymphomas, 59 bone cancers, 21 neuroblastomas, 15 Wilms' tumors, 6 rhabdomyosarcomas, and 13 other malignancies. Most participants (87%) were twenty or more year survivors. Mean scores on the physical performance subscale of the SF-36 among participants were lower than the population mean of 50 (Mean T-score of 47.27, 95% CI 46.4-48.2, P<0.001). Self reported physical function corresponded to measured performance on the PPT only 64.8% of the time for males and 73.6% of the time for females, and on the 6MW 75.9% of the time for females and 78.2% of the time for males. CONCLUSION: Survivors of childhood cancer report reduced physical function. Self reported physical function does not completely correspond to measured physical performance using standardized field tests.