Best of the Best Oral Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2020

Cardiac outcomes in left-sided breast cancer patients treated with radiotherapy: a pilot study comparison of deep inspiration breath hold (DIBH) and free breathing (#76)

Harish Sharma 1 , Xin Dong 2 , Anne Barnard 3 , Elizabeth Brown 1 , Nakia-Rae Beaton 1 , Patricia Browne 1 , Catriona Hargrave 4 , Sharon Watson 1 , Tao Mai 1 , Jennifer Harvey 1 , Arnold Ng 5 , Margot Lehman 1
  1. Radiation Oncology, Cancer Services, Princess Alexandra Hospital, Brisbane, Queensland, Australia
  2. School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
  3. Institute for Molecular Bioscience, University of Queensland, QFAB Bioinformatics, Brisbane, Queensland, Australia
  4. School of Clinical Sciences, Queensland University of Technology, Brisbane , Queensland , Australia
  5. Department of Cardiology, Princess Alexandra Hospital, Brisbane, Queensland, Australia

Aim

Cardiac toxicity is a potential side effect following radiotherapy (RT) to the chest.¹,² For left-sided breast cancer RT, Deep Inspiration Breath Hold (DIBH) has proved to be a very advantageous means of reducing RT doses to the heart as measured by planning dosimetry. This is especially pronounced when compared with free-breathing (FB).2,3 Our study aimed to investigate whether the dosimetric improvements as seen on RT treatment planning system Dose Volume Histograms, translated into improvements in clinical outcomes as measured by Echocardiography strain imaging.

Methods

Forty patients treated with curative intent adjuvant RT for left-sided breast cancer were prospectively recruited into the study.  Echocardiography strain imaging was conducted at baseline, and at six months post RT completion. Ten patients were treated in FB, while 30 patients were treated in DIBH.

Standard echo and strain parameters were measured, with Left Ventricular Global Longitudinal Strain (LVGLS) analysed to investigate any cardiac dysfunction between the FB and DIBH groups.

Results

Baseline comparisons showed no significant differences between the two groups in terms of Left Ventricular (LV) volume, ejection fraction, and GLS (p >0.2). LVGLS was impaired in both patient cohorts. There was a significant difference in LVGLS over time between the two groups (p <0.05). LVGLS worsened as FB RT progressed, with the trend continuing six months after RT completion.

Conclusion

This study demonstrated the changes that occur in myocardial tissue as measured by Echocardiography strain imaging in patients undergoing RT for left sided breast cancer.  As an entire group, LVGLS worsened compared to baseline. However, DIBH significantly reduced LVGLS measurements as compared with patients treated in FB, confirming the protective benefit of DIBH.

  1. 1. Darby SC, Ewertz M, McGale P, Bennet AM, Blom-Goldman U, Bronnum D et al. Risk of ischemic heart disease in women after radiotherapy for breast cancer. N Engl J Med [Internet]. 2013 Mar 14[cited 2019 Aug 29];368(11):987-998. Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa1209825.
  2. 2. Nissen HD, Appelt AL. Improved heart, lung and target dose with deep inspiration breath hold in a large clinical series of breast cancer patients. Radiother Oncol [Internet]. 2013 Jan[cited 2019 Aug 29];106(1):28-32. doi: 10.1016/j.radonc.2012.10.016. Epub 2012 Nov 28.
  3. 3. Latty D, Stuart KE, Wang W, Ahern V. Review of deep inspiration breath-hold techniques for the treatment of breast cancer. J Med Radiat Sci. 2015 Mar[cited 2019 Aug 29];62(1):74-81. doi: 10.1002/jmrs.96. Epub 2015 Feb 16.