Hypofractionated whole-breast radiation therapy: Does breast size matter?

Raquibul Hannan, Reid F. Thompson, Yu Chen, Karen Bernstein, Rafi Kabarriti, William Skinner, Chin C. Chen, Evan Landau, Ekeni Miller, Marnee Spierer, Linda Hong, Shalom Kalnicki

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Purpose: To evaluate the effects of breast size on dose-volume histogram parameters and clinical toxicity in whole-breast hypofractionated radiation therapy using intensity modulated radiation therapy (IMRT). Materials and Methods: In this retrospective study, all patients undergoing breast-conserving therapy between 2005 and 2009 were screened, and qualifying consecutive patients were included in 1 of 2 cohorts: Large-breasted patients (chest wall separation >25 cm or planning target volume [PTV] >1500 cm3) (nZ97) and small-breasted patients (chest wall separation <25 cm and PTV <1500 cm3) (nZ32). All patients were treated prone or supine with hypofractionated IMRT to the whole breast (42.4 Gy in 16 fractions) followed by a boost dose (9.6 Gy in 4 fractions). Dosimetric and clinical toxicity data were collected and analyzed using the R statistical package (version 2.12). Results: The mean PTV V95 (percentage of volume receiving >Z 95% of prescribed dose) was 90.18% and the mean V105 percentage of volume receiving >Z 105% of prescribed dose was 3.55% with no dose greater than 107%. PTV dose was independent of breast size, whereas heart dose and maximum point dose to skin correlated with increasing breast size. Lung dose was markedly decreased in prone compared with supine treatments. Radiation Therapy Oncology Group grade 0, 1, and 2 skin toxicities were noted acutely in 6%, 69%, and 25% of patients, respectively, and at later follow-up (>3 months) in 43%, 57%, and 0% of patients, respectively. Large breast size contributed to increased acute grade 2 toxicity (28% vs 12%, PZ.008). Conclusions: Adequate PTV coverage with acceptable hot spots and excellent sparing of organs at risk was achieved by use of IMRT regardless of treatment position and breast size. Although increasing breast size leads to increased heart dose and maximum skin dose, heart dose remained within our institutional constraints and the incidence of overall skin toxicity was comparable to that reported in the literature. Taken together, these data suggest that hypofractionated radiation therapy using IMRT is a viable and appropriate therapeutic modality in large-breasted patients.

Original languageEnglish (US)
Pages (from-to)894-901
Number of pages8
JournalInternational Journal of Radiation Oncology Biology Physics
Volume84
Issue number4
DOIs
StatePublished - Nov 15 2012

Keywords

  • Breast-conserving therapy
  • Hypofractionated radiation therapy
  • IMRT inverse planning
  • Large breast size
  • Prone treatment position

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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    Hannan, R., Thompson, R. F., Chen, Y., Bernstein, K., Kabarriti, R., Skinner, W., Chen, C. C., Landau, E., Miller, E., Spierer, M., Hong, L., & Kalnicki, S. (2012). Hypofractionated whole-breast radiation therapy: Does breast size matter? International Journal of Radiation Oncology Biology Physics, 84(4), 894-901. https://doi.org/10.1016/j.ijrobp.2012.01.093