Clinical Research Papers:
Dose coverage of axillary level IIII areas during whole breast irradiation with simplified intensity modulated radiation therapy in early stage breast cancer patients
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Li Zhang1,*, Zhao-zhi Yang1,*, Xing-xing Chen1,*, Jeffrey Tuan3, Jin-li Ma1, Xin Mei1, Xiao-li Yu1, Zhi-rui Zhou1, Zhi-min Shao2, Guang-yu Liu2 and Xiao-mao Guo1
1 Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
2 Department of Breast Surgery, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
3 Department of Radiation Oncology, National Cancer Centre Singapore, Singapore
* These authors have contributed equally to this work
Correspondence to:
Guang-yu Liu, email:
Xiao-mao Guo, email:
Keywords: breast cancer; positive sentinel lymph nodes, radiotherapy, intensity modulated radiation therapy, axillary level
Received: March 27, 2015 Accepted: May 18, 2015 Published: May 27, 2015
Abstract
Purpose: This study was designed to evaluate the dose coverage of axillary areas during whole breast irradiation with simplified intensity modulated radiation therapy (s-IMRT) and field-in-field IMRT (for-IMRT) in early stage breast cancer patients.
Methods: Sixty-one consecutive patients with breast-conserving surgery and sentinel lymph node biopsy were collected. Two plans were created for each patient: the s-IMRT and for-IMRT plan. Dosimetric parameters of axillary areas were compared.
Results: The average of mean doses delivered to the axillary level I areas in s-IMRT and for-IMRT plan were 27.7Gy and 29.1Gy (p = 0.011), respectively. The average of V47.5Gy, V45Gy and V40Gy (percent volume receiving≥ 47.5Gy, 45Gy and 40Gy) of the axillary level I in s-IMRT plan was significantly lower than that in for-IMRT plan (p < 0.001). For for-IMRT plans, patients with upper tangential border to humeral head ≤2cm, breast separation >19.3cm and body width >31.9cm had significantly higher mean dose in axillary level I area (p = 0.002, 0.007, 0.001, respectively).
Conclusion: Compared with for-IMRT plan, the s-IMRT plan delivered lower dose to axillary level I area. For centers using s-IMRT technique, caution should be exercised when selecting to omit axillary lymph node dissection for patients with breast conserving surgery and limited positive SLNs.