Feng Zhao1*, Guorong Yao1 , Jiayan Shen1 , Yongbiao Luo2 , Luyi Bu1 , Qibao Zhu2 , Zhongjie Lu1 , Senxiang Yan1 , 1.Department of Radiation Oncology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, PR China.2.Department of Radiation Oncology, Yiwu Central Hospital, Yiwu, Zhejiang 322000, PR China.

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  F Zhao

(Sunday, 7/29/2018) 3:00 PM - 6:00 PM

Room: Exhibit Hall

Purpose: It is well known that deep inspiration breath hold (DIBH) is an effective technique for reducing the cardiac dose during adjuvant radiotherapy (RT) for patients after breast-conserving surgery, which is a standard surgical procedure. However, in developing countries, the mastectomy is the most popular surgical procedure for patients with breast cancer. The purpose of this study is to quantify the benefit of DIBH on reducing doses to normal tissues and organs at risk, compared with free breathing (FB), during RT for the left-sided breast cancer patients after mastectomy.

Methods: A total of twelve post-mastectomy patients were enrolled in this study. Two simulation scans with FB and DIBH were performed for each patient. Dosimetric differences were compared between plans generated on both CT image sets. The two-tailed Wilcoxon signed-rank test was conducted to evaluate the dose metrics for the heart, left anterior descending coronary artery (LADCA), the ipsilateral lung and the breast PTV.

Results: There was no significant difference in the volume, mean dose, and homogeneity of planning target volume (PTV) between plans generated form FB and DIBH CT image sets (p>0.05). Compared with FB, the mean heart dose, LADCA dose and ipsilateral lung dose for DIBH plans were reduced from 3.48±1.32 Gy to 2.47±1.06 Gy (p<0.05), from 23.77±5.10 Gy to 15.7±7.22 Gy (p<0.05), and from 8.96±1.48 Gy to 7.81±0.80 Gy (p<0.05),respectively.

Conclusion: In this study, we focused on the dose benefits for patients with post-mastectomy. Compared with FB plans, DIBH plans achieved lower heart, LADCA and left lung doses. DIBH should be incorporated into the daily routine for post-mastectomy patient with left-sided breast cancer during adjuvant RT.

Funding Support, Disclosures, and Conflict of Interest: This study was supported by grant from the Health and Family Planning Commission of Zhejiang Province [grant number: 2018KY063] and by grant from Chinese Medicine Research Program of Zhejiang Province [grant number: 2018ZZ014].

Keywords

Breast, Dosimetry

Taxonomy

IM- Radiation dose and risk: General (Most Aspects)

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