Prog Med Phys.  2015 Dec;26(4):234-240. 10.14316/pmp.2015.26.4.234.

Comparison of Dosimetric Parameters of Patient with Large and Pendulous Breast Receiving Breast Radiotherapy in the Prone versus Supine Position

• Moon SY
• Yoon M
• Chung WK
• Chung M
• Shin DO
• Kim DW

• KMID: 2151757
• DOI: http://doi.org/10.14316/pmp.2015.26.4.234

Abstract

The purpose of this study is to analyze dosimetric parameters of patient with large and pendulous breast receiving breast radiotherapy in the prone versus supine position. The patient underwent computed tomography simulation in both prone and supine position. The homogeneity index (HI), conformity index (CI), coverage index (CVI) to the left breast as planning target volume (PTV) and the doses to the lung, heart, and right breast as organ at risk (OAR) were compared by using dose-volume histogram. The lifetime attributable risk (LAR) according to the prone and supine position was measured for the lung and right breast. The HI, CI of the PTV decreased 21.7%, 6.49%, respectively and the CVI increased 10.8% with the prone position. The mean and maximum dose to the left lung decreased 91.6%, 87.0%, respectively and the volume parameters also decreased over 99% with the prone position. The parameters to the right lung were same regardless of the position. The mean and maximum dose to the heart decreased 51.6%, 14.2% with the prone position. But the mean and maximum dose to the right breast increased unlike the other OARs. The LARs to the lung decreased 80.3% (left), 24.2% (right) but the LAR to the right breast doubled with the prone position. The prone position is a favorable alternative for irradiation of breast in patients with large and pendulous breasts.

Keyword

Large breast; Breast cancer; Prone position; Radiotherapy

MeSH Terms

Breast Neoplasms
Breast*
Heart
Humans
Lung
Prone Position
Radiotherapy*
Supine Position*

Figure

• 

  Fig. 1. Dose-volume histogram of the patient; (a) Prone (b) Supine. PTV: red, right lung: blue, left lung: bluish green, right breast: green, heart: plum.

• 

  Fig. 2. CT image of the patient; (a) Prone (b) Supine.

Reference

References

1. Annamaria Ferrari, Giovanni Ivaldi, Maria Cristina Leonardi, Elena Rondi, Roberto Orecchia: Prone breast radiotherapy in a patient with early stage breast cancer and a large pendulous breast. Tumori. 95:394–397. 2009.

2. Sung Kyu Kim, Sei One Shin, Myung Se Kim: Radiotherapy Treatment Planning using Computed Tomography in Breast Cancer. Korean Journal of Medical Physics. 3(2):59–65. 1992.

3. Grann A, McCormick B, Chabner ES, et al. Prone breast radiotherapy in early-stage breast cancer: a preliminary analysis. International Journal of Radiation Oncology∗ Biology∗ Physics. 47:319–325. 2000.

4. Suzy Kim, Yunseok Choi: Dosimetric Advantages of the Field-in-field Plan Compared with the Tangential Wedged Beams Plan for Whole-breast Irradiation. Korean Journal of Medical Physics. 25(4):199–204. 2014.

5. Loïc Feuvret, Georges Noël, Jean-Jacques Mazeron, Pierre Bey: Conformity index: A review. International Journal of Radiation Oncology∗ Biology∗ Physics. 64:333–342. 2006.

6. Myonggeun Yoon, Sung Yong Park, Dongho Shin, et al. A Simple Scoring Method to Calculate the Homogeneity and Coverage Indices of Dose Volume Histogram. Korean Journal of Medical Physics. 17(1):6–16. 2006.

7. Dong Wook Kim, Weon Kuu Chung, Sung Hwan Ahn, Myonggeun Yoon. Estimate of the Secondary Cancer Risk from Megavoltage CT in Tomotherapy, Journal of the Korean Physical Society. 62:1199–1203. 2013.

8. Dong Wook Kim, Weon Kuu Chung, Dongoh Shin, et al. Risk of second cancer from scattered radiation of intensitymodulated radiotherapies with lung cancer. Radiation Oncology 47 (. 2013.

9. Uwe Schneider, Linda Walsh: Cancer risk estimates from the combined Japanese A-bomb and Hodgkin cohorts for doses relevant to radiotherapy. Radiation Environment Biophysics. 47:253–263. 2008.

10. E. M. Donovan, H. James, M. Bonora, J. R. Yarnold, P. M. Evans: Second cancer incidence risk estimates using BEIR VII models for standard and complex external beam radiotherapy for early breast cancer. Medical Physics 39 (. 2012.

11. Anna M. Kirbya, Philip M. Evansb, Sarah J. Helyera, Ellen M. Donovana, Helen M. Converya, John R. Yarnoldb: A randomised trial of Supine versus Prone breast radiotherapy (SuPr study): Comparing setup errors and respiratory motion. Radiotherapy and Oncology. 100:221–226. 2011.

12. Lauren D. Stegman, Katherine P. Beal, Margie A. Hunt, Monica N. Fornier, Beryl McCormick: Long-term Clinical Outcomes of Whole-Breast Irradiation Delivered in the Prone Position. International Journal of Radiation Oncology∗ Biology∗ Physics. 68:73–81. 2007.