Radiotherapy to an intact breast was previously determined to have a positive correlation between breast separation measurement and hot spot dose. As breast separation measurement increased, hot spot dose increased. The purpose of this retrospective study was to determine if this correlation persisted despite current techniques including field-in-field (FiF) blocking and mixed photon energies. Radiation treatment plans on unilateral intact breasts from 90 female, early stage breast cancer patients treated with lumpectomy were analyzed. Plans were created using 3-dimensional conformal radiation therapy (3D-CRT) nondivergent opposing tangent beams, FiF technique, and 6 MV with or without higher energy photons. Data collected included breast separation measurement, hot spot point dose and location, number of beams, photon energy, clinical target volume (CTV) coverage and breast volume coverage. Correlations between breast separation measurement and each of these values were determined. The positive correlation between breast separation measurement and hot spot dose persisted despite incorporating FiF and mixed photon energies. Correlations were also found between breast separation and the number of beams as well as breast separation and photon energy. Larger breast separations tended to be treated with additional beams of higher photon energy. There were no correlations found between breast separation and CTV or breast volume coverage. The data in this study suggested the medical dosimetrist should expect hot spots above prescription dose of 106%, 107%, and 108% for small, medium and large breast separation sizes respectively. Additionally, adding a high energy photon bean may be indicated with medium and large breast separations.
To read this article in full you will need to make a payment
Purchase one-time access:Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
One-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:Subscribe to Medical Dosimetry
Already a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
- Survival comparisons for breast conserving surgery and mastectomy revisited: Community experience and the role of radiation therapy.Clin. Med. Res. 2015; 13: 65-73
- The effects of radiation therapy on quality of life of women with breast carcinoma.Cancer. 2000; 88: 2260-2266
- Radiotherapy using hard wedges is no longer appropriate and should be discontinued.Med. Phys. 2016; 43: 1031-1034
- Second cancer risk after 3D-CRT, IMRT and VMAT for breast cancer.Radiother. Oncol. 2014; 110: 471-476
- Comparison of different radiotherapy planning techniques for breast cancer after breast conserving surgery.Asian Pac. J. Cancer Prev. 2018; 19: 2929-2934
- Dosimetric analysis of intact breast irradiation in off-axis planes.Int. J. Radiat. Oncol. Biol. Phys. 1997; 39: 261-267
- Three-dimensional dose distribution of tangential breast irradiation: results of a multicentre phantom dosimetry study.Radiother. Oncol. 2000; 57: 61-68
- Isoseparation curves: A mechanism for optimizing off-axis dose homogeneity of intact breast irradiation.Radiat. Oncol. Investig. 1998; 6: 191-198
- Irregular surface compensation for radiotherapy of the breast: Correlating depth of the compensation surface with breast size and resultant dose distribution.Br. J. Radiol. 2010; 83: 159-165
- Forward-planned, multiple-segment, tangential fields with concomitant boost in the treatment of breast cancer.Med. Dosim. 2004; 29: 265-270
- Risks and benefits of reducing target volume margins in breast tangent radiotherapy.Australas. Phys. Eng. Sci. Med. 2017; 40: 305-315
- The impact of dose-specification policies upon nominal radiation dose received by breast tissue in the conservation treatment of breast cancer.Int. J. Radiat. Oncol. Biol. Phys. 2000; 47: 841-848
- Choosing wisely? Patterns and correlates of the use of hypofractionated whole-breast radiation therapy in the state of Michigan. Radiation Oncology Quality Consortium.Int. J. Radiat. Oncol. Biol. Phys. 2014; 90: 1010-1016
- Patterns of dose variability in radiation prescription of breast cancer.Radiother. Oncol. 1997; 44: 83-89
- Correlation of breast dose heterogeneity with breast size using 3D CT planning and dose-volume histograms.Radiother. Oncol. 1995; 34: 210-218
White, J.; Tai, A.; Arthur, D.; et al. Breast cancer atlas for radiation therapy planning: Consensus definitions. Radiation Therapy Oncology Group (RTOG) Web site. https://www.rtog.org/LinkClick.aspx?fileticket=SQhssxHu7Jg%3d&tabid=227. Accessed June 28, 2018.
- Evaluation of dose calculation algorithms using different density materials for in-field and out-of-field conditions.Exp. Oncol. 2019; 41: 46-52
Published online: September 11, 2019
Accepted: August 18, 2019
Received in revised form: July 2, 2019
Received: January 8, 2019
© 2019 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.