Uncertainties in estimating heart doses from 2D-tangential breast cancer radiotherapy

Background and purpose We evaluated the accuracy of three methods of estimating radiation dose to the heart from two-dimensional tangential radiotherapy for breast cancer, as used in Denmark during 1982–2002. Material and methods Three tangential radiotherapy regimens were reconstructed using CT-based planning scans for 40 patients with left-sided and 10 with right-sided breast cancer. Setup errors and organ motion were simulated using estimated uncertainties. For left-sided patients, mean heart dose was related to maximum heart distance in the medial field. Results For left-sided breast cancer, mean heart dose estimated from individual CT-scans varied from <1 Gy to >8 Gy, and maximum dose from 5 to 50 Gy for all three regimens, so that estimates based only on regimen had substantial uncertainty. When maximum heart distance was taken into account, the uncertainty was reduced and was comparable to the uncertainty of estimates based on individual CT-scans. For right-sided breast cancer patients, mean heart dose based on individual CT-scans was always <1 Gy and maximum dose always <5 Gy for all three regimens. Conclusions The use of stored individual simulator films provides a method for estimating heart doses in left-tangential radiotherapy for breast cancer that is almost as accurate as estimates based on individual CT-scans.

[1]  J. Cuzick,et al.  Increased cardiovascular mortality more than fifteen years after radiotherapy for breast cancer: a population-based study , 2007, BMC Cancer.

[2]  Per Hall,et al.  Cardiac dose estimates from Danish and Swedish breast cancer radiotherapy during 1977–2001 , 2011, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[3]  Carsten Brink,et al.  Automatic segmentation of the heart in radiotherapy for breast cancer , 2014, Acta oncologica.

[4]  Joseph O Deasy,et al.  CERR: a computational environment for radiotherapy research. , 2003, Medical physics.

[5]  J. Sonke,et al.  Image-guided radiotherapy for left-sided breast cancer patients: geometrical uncertainty of the heart. , 2012, International journal of radiation oncology, biology, physics.

[6]  R. Collins,et al.  Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials , 2005, The Lancet.

[7]  Aamer Chughtai,et al.  Development and validation of a heart atlas to study cardiac exposure to radiation following treatment for breast cancer. , 2011, International journal of radiation oncology, biology, physics.

[8]  Andrew Nisbet,et al.  Cardiac exposures in breast cancer radiotherapy: 1950s-1990s. , 2007, International journal of radiation oncology, biology, physics.

[9]  S. Korreman,et al.  IMPACT OF AN OFF-LINE CORRECTION PROTOCOL ON SETUP UNCERTAINTY IN MODERN BREAST CANCER RADIATION THERAPY , 2009 .

[10]  M. S. Thomsen,et al.  Delineation of target volumes and organs at risk in adjuvant radiotherapy of early breast cancer: National guidelines and contouring atlas by the Danish Breast Cancer Cooperative Group , 2013, Acta oncologica.

[11]  J. Bradley,et al.  The impact of central lung distance, maximal heart distance, and radiation technique on the volumetric dose of the lung and heart for intact breast radiation. , 2002, International journal of radiation oncology, biology, physics.

[12]  P. Hall,et al.  Risk of ischemic heart disease in women after radiotherapy for breast cancer. , 2013, The New England journal of medicine.

[13]  L. Boersma,et al.  Cardiotoxic effects of tangential breast irradiation in early breast cancer patients: the role of irradiated heart volume. , 2007, International journal of radiation oncology, biology, physics.

[14]  R. Peto,et al.  Long-term mortality from heart disease and lung cancer after radiotherapy for early breast cancer: prospective cohort study of about 300,000 women in US SEER cancer registries. , 2005, The Lancet. Oncology.

[15]  L. Holmberg,et al.  Radiation to supraclavicular and internal mammary lymph nodes in breast cancer increases the risk of stroke , 2009, British Journal of Cancer.

[16]  S. Darby,et al.  Estimating cardiac exposure from breast cancer radiotherapy in clinical practice. , 2009, International journal of radiation oncology, biology, physics.

[17]  M. Overgaard,et al.  Postoperative radiotherapy in DBCG during 30 years. Techniques, indications and clinical radiobiological experience , 2008, Acta oncologica.

[18]  P. Hall,et al.  Mortality from cardiovascular disease more than 10 years after radiotherapy for breast cancer: nationwide cohort study of 90 000 Swedish women , 2003, BMJ : British Medical Journal.

[19]  M. S. Thomsen,et al.  Quality assurance of conventional non-CT-based internal mammary lymph node irradiation in a prospective Danish Breast Cancer Cooperative Group trial: The DBCG-IMN study , 2013, Acta oncologica.

[20]  V. Ferrari,et al.  Association between tangential beam treatment parameters and cardiac abnormalities after definitive radiation treatment for left-sided breast cancer. , 2008, International journal of radiation oncology, biology, physics.

[21]  R Peto,et al.  Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10 801 women in 17 randomised trials , 2011, The Lancet.