Persistent Impairment in Cardiopulmonary Fitness following Breast Cancer Chemotherapy.

Foulkes S; Howden EJ; Bigaran A; Janssens K; Antill Y; Loi S; Claus P; Haykowsky MJ; Daly RM; Fraser SF;
La Gerche A;

Medicine And Science In Sports And Exercise [Med Sci Sports Exerc] 2019 Mar 01. Date of Electronic Publication: 2019 Mar 01.

Purpose: Anthracycline chemotherapy (AC) is associated with acute reductions in cardiopulmonary fitness (VO2peak). We sought to determine whether changes in VO2peak and cardiac function persisted at 12-months post-AC completion, and whether changes in cardiac function explain the heightened long-term heart failure risk.
Methods: Women with breast cancer scheduled for AC (n=28) who participated in a non-randomized trial of exercise training (ET; n=14) or usual care (UC; n=14) during AC completed a follow-up evaluation 12-months post-AC completion (16-months from baseline). At baseline, 4-months, and 16-months, participants underwent a resting echocardiogram (left ventricular ejection fraction, LVEF; global longitudinal strain, GLS), a blood sample (troponin; b-type natriuretic peptide), a cardiopulmonary exercise test, and cardiac MRI measures of stroke volume (SV), heart rate (HR) and cardiac output (Qc) at rest, and during intense exercise.
Results: Seventeen women (UC: n=8; ET: n=9) completed evaluation at baseline, 4-months and 16-months. At 4-months, AC was associated with 18% and 6% reductions in VO2peak in the UC and ET groups respectively, that persisted at 16-months (UC: -16%; ET: -7%), and was not attenuated by ET (interaction, P=0.10). Exercise Qc was lower at 16-months compared to baseline and 4-months (P<0.001), which was due to a blunted augmentation of SV during exercise (P=0.032; a 14% reduction in peak SV), with no changes in HR response. There was a small reduction in resting LVEF (baseline to 4-months) and GLS (between 4-months and 16-months), and an increase in troponin (baseline to 4-months), but only exercise Qc was associated with VO2peak (R=0.47, P<0.01).
Conclusion: Marked reductions in VO2peak persisted 12-months following anthracycline-based chemotherapy, which was associated with impaired exercise cardiac function.