Impact of patient and treatment characteristics on heart and lung dose in adjuvant radiotherapy for left-sided breast cancer

Tobias Finazzi,Van-Trinh Nguyen,Alexandros Papachristofilou,Frank Zimmermann

doi:10.1186/s13014-019-1364-3

Tobias Finazzi, Van-Trinh Nguyen + Show 2 more

Open Access

https://doi.org/10.1186/s13014-019-1364-3

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Abstract

PurposeThe heart and lungs are routinely exposed to incidental irradiation during adjuvant radiotherapy (RT) of breast cancer. We analyzed the impact of patient and treatment characteristics on heart and lung dose in left-sided breast RT.MethodsWe analyzed 332 female patients treated with left-sided breast RT between 2013 and 2018. Mean heart dose (MHD), left mean lung dose (MLD) and heart / lung V20Gy were collected from treatment plans. Patients were stratified by RT technique (3D-conformal RT, 3DCRT; intensity-modulated RT, IMRT; volumetric modulated arc therapy, VMAT) and target volumes, including lymph node RT (LN-RT). Patient characteristics (body mass index (BMI), heart and lung volume) were assessed using correlation analyses.ResultsLN-RT was performed in 111 patients with increased MHD (median 4.6 vs. 3.3 Gy; p < .01), left MLD (14.8 vs. 7.7 Gy; p < .01) and left lung V20Gy (30.0% vs. 14.4%; p < .01) compared to treatment without LN-RT. Internal mammary LN-RT further increased organ doses compared to RT involving only supraclavicular +/− axillary LN (p < .01 for all values; MHD 6.9 vs. 4.2 Gy). In 221 patients treated without LN-RT, IMRT/VMAT was associated with higher left lung doses (MLD 9.1 vs. 7.4 Gy, p < .01; V20Gy 18.8% vs. 14.0%, p < .01) compared to 3DCRT. A negative correlation between total lung volume and both MHD (r = − 0.38; p < .01) and heart V20Gy (r = − 0.37; p < .01), as well as a weak positive correlation of BMI and MHD (r = 0.27; p < .01) were observed.ConclusionsIn adjuvant RT for left-sided breast cancer, LN-RT is associated with a marked increase in heart and lung doses, particularly with internal mammary LN-RT. Potential advantages of IMRT/VMAT for breast or chest wall RT need to be weighed against a moderately increased lung dose.

Highlights

Adjuvant radiotherapy (RT) is a standard procedure after surgery for breast cancer, reducing the risk of locoregional recurrence and breast cancer death after breast conserving surgery, as well as after mastectomy in highrisk patients [1, 2]
Treatment characteristics A total of 332 female patients treated with left-sided breast RT were eligible for analysis
We report on the impact of patient and treatment characteristics on heart and lung dose in a contemporary cohort of patients treated with left-sided breast RT

Summary

Introduction

Adjuvant radiotherapy (RT) is a standard procedure after surgery for breast cancer, reducing the risk of locoregional recurrence and breast cancer death after breast conserving surgery, as well as after mastectomy in highrisk patients [1, 2]. Since most breast cancer patients are cured of their disease, potential long term hazards of RT. Improved RT techniques can potentially better spare organs at risk (OAR), heart and lung dose remain important dosimetric surrogates for long term effects and influence clinical decision making in adjuvant RT for (left-sided) breast cancer. Finazzi et al Radiation Oncology (2019) 14:153 the impact of patient and treatment characteristics on heart and lung dose in a contemporary cohort of patients treated with left-sided breast RT, aiming to better quantify potential relationships and allow for a more refined consideration of these factors in clinical practice

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