Comparing different techniques of Post Axillary field in Breast Cancer Treatment

Document Type: Conference Proceedings

Authors

1 Medical Physics department, Reza Radiation Oncology Center, Mashhad, Iran. E-mail:sekhoshkharam@yahoo.com telephone: 09153224195

2 Medical Physics department, Reza Radiation Oncology Center, Mashhad, Iran. Medical Physics Department, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

3 Medical Physics department, Reza Radiation Oncology Center, Mashhad, Iran.

Abstract

As we know breast cancer is the second death reason in Iran. One step of treatment process
is radiotherapy, which needs careful consideration of contouring and therapeutic techniques
Lung, thyroid, spinal cord, trachea and humerus are sensitive organs in breast cancer
radiation therapy.  The most clinical studies recommended two ways for delivering 95
percent of dose to supraclavicular and axillary nodes, one of them is an anterior field with a
posterior axillary boost (AP-PAB) technique for the axillary lymph nodes and supraclavicular treatment and another one is an anterior to posterior parallel pair (AP-PA) technique, at
Reza Radiotherapy and  Oncology  Center in Mashhad  an anterior  to posterior parallel pair
(AP-PA) technique was used. The aim of this study is comparing and evaluating delivered
dose for all organs in these techniques.
The study population comprised breast cancer patient in Reza Radiation and Oncology
Center (2016). Prowess panther version 5.2 was used as a treatment planning software.
Plans for 20 breast cancer cases were done with (AP-PAB) technique and (AP-PA) technique.
In each techniques delivered dose was investigated for lung, spinal cord, humerus, thyroid,
trachea, supraclavicular lymph node, axillary lymph node and the hot spot. Organ at risk and
nodes delivered dose were compared.
By comparing two technique dose volume histogram for each breast cancer case, based on
the analysis of data collected by software SPSS (p value=0.7 for average dose at 30% of lung
volume, p value=0.2 for average dose at 95% of axillary lymph nodes volume, p value=0.8
for average dose at thyroid, p value=0.8 for average dose at humerus, p value=0.6 for average
dose at trachea, p value=0.5 for average of maximum dose at spinal cord and p value=0.08
for average dose at 95% of supraclavicular lymph nodes volume. According to the results
there is not significant difference between these techniques because p value is higher than
0.05 for all organs in the other hand average dose at 30% of lung volume is 2% lower in (AP-
PAB) technique, average dose at thyroid is 1% lower in (AP-PAB) technique, average dose at
trachea is 4% lower and average of maximum dose at spinal cord is 4% lower in (AP-PAB)
technique. Average dose at 95% of axillary lymph nodes volume is 0.9% higher in (AP-PAB)
technique also average dose at 95% of supraclavicular lymph nodes volume is 1.2% higher
and average dose at humerus is 1.7% lower in (AP-PA) technique. This study shows (AP-
PAB) technique is acceptable for patients with critical conditions (cases with high dose
constrain of organ at risk.

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