Is there an advantage to delivering breast boost in the lateral decubitus position?

Abstract

Abstract Background The purpose of this study was to compare the change in depth of target volume and dosimetric parameters between the supine and lateral decubitus positions for breast boost treatment with electron beam therapy. Methods We analyzed 45 patients who were treated, between 2009–2010, with whole breast radiation (WBRT) followed by a tumor bed boost in the lateral decubitius position. Tumor bed volume, distance from skin to the maximal depth of the tumor bed, D90 (dose covering 90% of the tumor bed volume), maximal dose, electron energy and doses to heart and lungs were compared. Additional variables of body mass index (BMI) and tumor bed location were also analyzed to see if there was a benefit limited to any subgroup. Results Median BMI for the 45 patients treated was 30.6 (20.6-42.4). When comparing the supine scan to the lateral decubitus scan, there was no significant difference in the tumor bed volume (p = 0.116). There was a significant difference between depth to the tumor bed in the supine scan and lateral decubitus scan (p Conclusions Delivering a tumor bed boost in the lateral decubitus position reduces the distance to the tumor bed allowing for a lower energy treatment to be used to treat breast cancer. It improves coverage and decreases maximal dose to the target volume, all of which would help reduce skin morbidities and should be considered for patients with upper outer quadrant disease, irrespective of BMI status.

Keywords

• Breast cancer
• Body mass index
• Electron beam therapy