A Longitudinal Study of Clinical Benefits with Implementation of the Deep Inspiration Breath-Hold Technique in Post-Operative Radiotherapy for Left-Sided Breast Cancer

Chunhui Han,Jeffrey Y C Wong,Nayana Vora,Sean Zhang,An Liu

doi:10.4236/ijmpcero.2019.83014

Abstract

Purpose/Objectives: We aimed to report clinical effects on critical organ dose and cardiac toxicity from implementation of the deep inspiration breath-hold (DIBH) technique in post-operative extern-beam radiotherapy of patients with left-sided breast cancer, using longitudinal clinical data. Materials/Methods: We retrieved three groups of patients who received post-operative radiotherapy of left-sided breast cancer in our institution in recent years: Groups A and B consist of patients whose treatment did not include internal mammary nodes (IMN) and who were treated with the free breathing technique and with the DIBH technique, respectively, and Group C consists of patients whose radiotherapy included internal mammary nodes with the DIBH technique. Dose parameters for the heart and left lung were retrieved from the treatment plans. Radiation-induced cardiac risks were estimated using existing risk models. Results: The average heart dose was 2.65 ± 0.98 Gy, 1.10 ± 0.29 Gy, and 1.26 ± 0.25 Gy in Groups A, B, and C, respectively. The average heart volumes receiving at least 25 Gy were 7.10 ± 9.79 cc in Group A, 0.07 ± 0.22 cc in Group B, and 0.03 ± 0.08 cc in Group C. On average, the excessive risk of having ischemic heart disease was estimated to be 19.6%, 8.1%, and 9.3% in Groups A, B, and C, respectively. The mean left lung doses were 5.73 ± 1.86 Gy, 5.93 ± 1.55 Gy, and 9.13 ± 1.57 Gy in Groups A, B, and C, respectively. Conclusion: Implementation of the DIBH technique significantly lowered heart dose and decreased the ischemic heart disease risk in patients receiving post-operative radiotherapy for left-sided breast cancer, without significant increase in left lung dose.

Highlights

Breast cancer is the most commonly diagnosed cancer in women in the United States with 268,600 newly diagnosed breast cancer cases expected in 2019 [1]
Materials/Methods: We retrieved three groups of patients who received post-operative radiotherapy of left-sided breast cancer in our institution in recent years: Groups A and B consist of patients whose treatment did not include internal mammary nodes (IMN) and who were treated with the free breathing technique and with the deep inspiration breath-hold (DIBH) technique, respectively, and Group C consists of patients whose radiotherapy included internal mammary nodes with the DIBH technique
The goals of this study are: 1) to evaluate clinically achievable reduction of heart dose with the implementation of the DIBH technique for post-operative left-sided breast cancer patients; 2) to estimate the reduction of ischemic heart disease risks with the DIBH technique; and 3) to evaluate dosimetric effect on the inflated left lung volume with the DIBH technique

Summary

Introduction

Breast cancer is the most commonly diagnosed cancer in women in the United States with 268,600 newly diagnosed breast cancer cases expected in 2019 [1]. Post-operative radiation therapy (RT) is an important adjuvant treatment modality for lowering cancer recurrence rate [2] [3]. In post-operative external beam irradiation of the left-sided breast cancer patients, potential side effects include acute and chronic toxicities to the lung, ribs, heart, skin, as well as increased risks of radiation-induced secondary cancer occurrence in the thoracic region [6] [7] [8] [9] [10]. Heart and lung toxicities could lead to sever long-term morbidity and mortality [6]. Given good survival expectations for breast cancer patients, special attention should be paid to the heart and lung dose during post-operative irradiation to minimize long-term cardiovascular and pulmonary morbidity and mortality rates

Objectives

Methods

Results