Thoracic growth deficiency in childhood cancer survivors may cause overestimation of lung disease

Abstract

Introduction Survivors of childhood cancers undergo routine pulmonary function testing as they are at an increased lifetime risk for significant lung disease. However, this population also demonstrates growth abnormalities that could influence the interpretation of these tests, as reference equations are based on standing height. We aim to determine the impact of the relative thoracic growth deficiency in childhood cancer survivors on the interpretation of pulmonary function testing. Methods Standing height and upper segment length (USL) in childhood cancer survivors undergoing pulmonary function testing at a single academic center were compared to age‐matched historical standards. Additionally, pulmonary function tests were compared to reference values generated from standing height and doubled USL. Results Data were obtained from 107 cancer survivors. While the subjects demonstrated an overall 6.8% lower standing height vs historical standards, they also demonstrated relative thoracic growth abnormality with a further 9.9% decrement in the ratio USL to standing height. The use of doubled upper segment length as a surrogate measure for standing height in pulmonary function reference equations decreased the number of patients with restrictive lung disease as indicated by spirometry. Conclusions Childhood cancer survivors have disproportionately worse thoracic growth deficiency vs appendicular growth deficiency. As a result, their USL is disproportionately short for their standing height, which is most commonly used in pulmonary function testing reference equations. This leads to an increased likelihood in these patients meeting pulmonary function test criteria for restrictive lung disease.

Late effects in survivors of high‐risk neuroblastoma following stem cell transplant with and without total body irradiation

“…There was significant difficulty in finding suitable organs, given that the chest wall was the size of a 4-year-old when the patient was 17 years of age. 21 In this cohort, 10/39 (25%) of the patients were symptomatic; symptoms were consistent with either obstructive lung disease or restrictive/interstitial lung disease. Not all of these symptoms correlated with abnormal PFTs.…”

Pediatric pulmonology year in review 2019: Physiology

“…Childhood cancer survivors (CCS) have thoracic growth deficiency, which disproportionately affects their upper segment length (USL) compared with children without cancer. Dean et al 13 hypothesized that CCS have a disparity in the ratio of USL to standing height that leads to overestimation of PFT abnormalities. To test this hypothesis, they compared PFT results in CCS to age‐matched historical standards and also used double the USL as an alternative for standing height in calculation of predicted PFT values.…”

Pediatric pulmonology 2019 year in review: rare and diffuse lung disease

“…Impaired pulmonary function in childhood cancer survivors (CCS) is associated with decreased physical function; restrictive defects and D L CO are the most commonly observed pattern 47–49 . Growth abnormalities also may occur among CCS, 50,51 leading Dean et al 52 to hypothesize that impaired thoracic growth may play a role in PFT abnormalities observed among this population. They found that 107 CCS were shorter on average than historical controls, with disproportionate shortening of the upper body segment—the distance from the top of the head to the end of the coccyx.…”