Postmastectomy chest wall radiation of left-sided carcinoma breast - a dosimetric comparison between electrons and photons

V. L. Anusha Konakalla, Naga C. S. Darisi, Kesavan Chandrasekharan, D. S. Raju Naidu


Background: For carcinoma breast patients requiring post mastectomy radiation therapy (PMRT), tangential photon beam (PB) is commonly used technique. The physical nature of electrons results in sharp dose fall off and reduces organs at risk (OAR) doses. Aim of the present study is to compare the coverage of chest wall and doses received by OARs – heart and lung between electron and photon beam plans in left sided breast cancer patients requiring PMRT.

Methods: This study was done in 22 left sided carcinoma breast patients treated at GSL Medical College between May to December 2017. Both tangential PB plans and electron beam (EB) plans were generated on simulation computed tomography (CT) for each patient and both plans were compared. A dose of 50 Gy was prescribed to planning target volume (PTV) in 25 fractions.

Results: The PB plans provided superior homogeneity index (HI) and conformity index CI compared to the EB plans (p<0.05). There was significant difference in favour of electron-beam plans for mean heart dose (p=0.0312), V25 Gy (p=0.029), V45 Gy (p=0.001) and V20 Gy of left lung (p=0.042). There was no significant difference in mean lung dose.

Conclusions: Dosimetric data from this study suggests that PMRT with the electron beam can reduce doses to the heart and left lung with acceptable target coverage. It needs further research in the clinical setting.


Electron beam, Photon beam, Post mastectomy radiation therapy, Locally advanced breast carcinoma

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Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2021;71 209-49.

EBCTCG (Early Breast Cancer Trialists' Collaborative Group). McGale P, Taylor C, Correa C, Cutter D, Duane F, Ewertz M, et al. Effect of radiotherapy after mastectomy and axillary surgery on 10-year recurrence and 20-year breast cancer mortality: meta-analysis of individual patient data for 8135 women in 22 randomised trials. Lancet. 2014;383:2127-35.

Wang H, Wei J, Zheng Q, Meng L, Xin Y, Yin X, et al. Radiation-induced heart disease: a review of classification, mechanism and prevention. Int J Biol Sci. 2019;15:2128-38.

Hooning MJ, Botma A, Aleman BM, Baaijens MH, Bartelink H, Klijn JG, et al. Long-term risk of cardiovascular disease in 10-year survivors of breast cancer. J Natl Cancer Inst. 2007;99:365-75.

Darby SC, Ewertz M, McGale P, Bennet AM, Blom-Goldman U, Brønnum D, et al. Risk of ischemic heart disease in women after radiotherapy for breast cancer. N Engl J Med. 2013;368:987-98.

McGale P, Darby SC, Hall P, Adolfsson J, Bengtsson NO, Bennet AM, et al. Incidence of heart disease in 35,000 women treated with radiotherapy for breast cancer in Denmark and Sweden. Radiother Oncol. 2011;100:167-75.

Jeba J, Isiah R, Subhashini J, Backianathan S, Thangakunam B, Christopher DJ. Radiation Pneumonitis After Conventional Radiotherapy For Breast Cancer: A Prospective Study. J Clin Diagn Res. 2015;9:1-5.

Gokula K, Earnest A, Wong LC. Meta-analysis of incidence of early lung toxicity in 3-dimensional conformal irradiation of breast carcinomas. Radiat Oncol. 2013;8:268.

Pierce LJ, Butler JB, Martel MK, Normolle DP, Koelling T, Marsh RB, et al. Postmastectomy radiotherapy of the chest wall: Dosimetric comparison of common techniques. Int J Radiat Biol Phys. 2002;52:1220-30.

Breast cancer atlas for radiation therapy planning: consensus definitions. Available at: BreastCancerAtlas.aspx. Accessed on 24 October 24 2021.

Chavaudra J, Bridier A. Definition of volumes in external radiotherapy: ICRU reports 50 and 62. Cancer Radiother. 2001;5(5):472-8.

Opp D, Forster K, Li W, Zhang G, Harris EE. Evaluation of bolus electron conformal therapy compared with conventional techniques for the treatment of left chest wall postmastectomy in patients with breast cancer. Med Dosim. 2013;38:448-53.

Gez E, Ashaf N, Barderoma R,Rosenblatt E, Kuten A. Postmastectomy electron-beam chest-wall irradiation in Women with breast cancer. Int J Radiat Oncol Biol Phys. 2004;60:1190-4.

Seppenwoolde Y, Lebesque JV, de Jaeger K, Belderbos JS, Boersma LJ, Schilstra C, Henning GT,et al.Compar-ing different NTCP models that predict the incidence of radi-ation pneumonitis. Normal tissue complication probability. Int J Radiat Oncol Biol Phys. 2003;55:724-35.

Graham MV, Purdy JA, Emami B, Harms W, Bosch W, Lockett MA, et al. Clinical dose–volume histogram analysis for pneumonitis after 3D treatment for non–small cell lung cancer (NSCLC). Int J Radiat Oncol Biol Phys. 1999;45:323-9.

Chung E, Corbett JR, Moran JM, Griffith KA, Marsh RB, Feng M, et al. Is there a dose-response relationship for heart disease with low-dose radiation therapy? Int J Radiat Oncol Biol Phys. 2013;85:959-64.

Hong L, Ballangrud A, Mc Cormick B, Mechalakos J. Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm. Med Dosim. 2018;43:230-6.

Spierer MM, Hong LX, Wagman RT, Katz MS,Spierer RL,McCornickB.Postmastectomy CT-based electron beam radiotherapy: Dosimetry, efficacy, and toxicity in 118 patients. Int J Radiat Oncol Biol Phys. 2004;60:1182-9.

Vaiduriam M, Parameswaran S, Arjunan A, Jayaprakash PG, Ratheesan K, Saju B, et al. Dosimetric Comparison Between Electrons and Tangential Photons in Postmastectomy Chest Wall Irradiation. Int J Radiat Oncol Biol Phys. 2013;87(2):6-7.

Kesava Ramgopal A, Mahendran H, Deepa T, Uma Rajeswari S, Anbalagan D, Kumar Reddy J.Postmastectomy Chest Wall Radiation of Left-Sided Breast Cancer Patients With Single Energy Electron Beam Versus 3-Dimensional Conformal Radiation Therapy With Photons: Analysis of Dosimetric Parameters. Int J Radiat Oncol Biol. 2014;268.

Ma J, Li J, Xie J, Chen J, Zhu C, Cai G, et al. Post mastectomy linac IMRT irradiation of chest wall and regional nodes: Dosimetry data and acute toxicities. Radiat Oncol. 2013;8:81.

Korreman SS, Pedersen AN, Nøttrup TJ, Specht L, Nyström H. Breathing adapted radiotherapy for breast cancer: comparison of free breathing gating with the breath‐hold technique. Radiother Oncol. 2005;76:311-8.

Rudat V, Alaradi AA, Mohamed A, Ai-Yahya K, Altuwaijri S. Tangential beam IMRT versus tangential beam 3D-CRT of the chest wall in postmastectomy breast cancer patients: a dosimetric comparison. Radiat Oncol. 2011;6:26.

Fagundes M, Hug E, Pankuch M. Proton therapy for local regionally advanced breast cancer maximizes cardiac sparing. Int J Part Ther. 2015;1:827-44.

Stovall M, Smith SA, Langholz BM, Boice JD, Shore RE, Andersson M, et al. Dose to the contralateral breast from radiotherapy and risk of second primary breast cancer in the WECARE study. Int J Radiat Oncol Biol Phys. 2008;72:1021-30.