Respiratory Factors Contributing to Exercise Intolerance in Breast Cancer Survivors: A Case-Control Study

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• 作者：Denis E. O'Donnell ; MD ; FRCPC^a ; ^{odonnell@queensu.ca" class="auth_mail" title="E-mail the corresponding author} ; Katherine A. Webb ; MSc^a ; Daniel Langer ; PhD^a ; ^c ; Amany F. Elbehairy ; MD ; PhD^a ; ^d ; J. Alberto Neder ; MD^a ; Deborah J. Dudgeon ; MD^b
• 关键词：Breast cancer ; dyspnea ; muscle weakness ; exercise ; cardiopulmonary exercise test
• 刊名：Journal of Pain and Symptom Management
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：52
• 期：1
• 页码：54-63
• 全文大小：321 K

文摘

Breast cancer survivors often experience activity-related dyspnea and exercise intolerance, but the underlying mechanisms remain unknown.

Objectives

We evaluated physiological contributors to reduced peak oxygen uptake (VO₂), with particular attention to the role of respiratory impairment.

Methods

We compared symptom assessments, respiratory and peripheral muscle strength, pulmonary function, and ventilatory responses to symptom-limited incremental treadmill exercise in 29 women who had survived breast cancer and 29 age-matched healthy controls.

Results

Peak VO₂ was reduced more than 20%, on average, in the cancer group compared with controls (P < 0.001). Slopes of dyspnea intensity ratings over ventilation or VO₂ were >50% greater in the cancer group compared to controls (P < 0.05). Women with breast cancer had lower lung diffusing capacity for carbon monoxide (D_LCO), respiratory and limb muscle strength, and ventilatory thresholds during exercise compared with controls (all P < 0.05). During exercise, indices of ventilatory efficiency were similar to controls, but inspiratory capacity (IC) was lower and breathing pattern was more rapid and shallow in the cancer group (P < 0.05). The lower peak VO₂ in the cancer group was associated with greater dyspnea intensity, and lower D_LCO, IC and ventilatory threshold (all P < 0.05).

Conclusion

Breast cancer survivors had greater peripheral and respiratory muscle weakness, greater reduction of IC, impaired lung diffusion, and evidence of deconditioning compared with controls. Exercise intolerance was multifactorial and correlated well with the combination of these factors as well as with exertional dyspnea. Individualized physiological testing in breast cancer survivors can identify important contributors to exercise intolerance which can be targeted for treatment.