title: Estimation of the risk of secondary malignancy arising from whole-breast irradiation: comparison of five radiotherapy modalities, including TomoHDA.
abstract: The risk of secondary cancer from radiation treatment remains a concern for long-term breast cancer survivors, especially those treated with radiation at the age younger than 45 years. Treatment modalities optimally maximize the dose delivery to the tumor while minimizing radiation doses to neighboring organs, which can lead to secondary cancers. A new TomoTherapy treatment machine, TomoHDATM, can treat an entire breast with two static but intensity-modulated beams in a slice-by-slice fashion. This feature could reduce scattered and leakage radiation doses. We compared the plan quality and lifetime attributable risk (LAR) of a second malignancy among five treatment modalities: three-dimensional conformal radiation therapy, field-in-field forward-planned intensity-modulated radiation therapy, inverse-planned intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy, and TomoDirect mode on the TomoHDA system. Ten breast cancer patients were selected for retrospective analysis. Organ equivalent doses, plan characteristics, and LARs were compared. Out-of-field organ doses were measured with radio-photoluminescence glass dosimeters. Although the IMRT plan provided overall better plan quality, including the lowest probability of pneumonitis, it caused the second highest LAR. The TomoTherapy plan provided plan quality comparable to the IMRT plan and posed the lowest total LAR to neighboring organs. Therefore, it can be a better treatment modality for younger patients who have a longer life expectancy.
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Han
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Nava
authors.initials: N
authors.lastname: Paudel
authors.affiliation: Department of Bio-Convergence Engineering, Korea University, Seoul, Korea.
authors.forename: Jiwon
authors.initials: J
authors.lastname: Sung
authors.affiliation: Department of Bio-Convergence Engineering, Korea University, Seoul, Korea.
authors.forename: Myonggeun
authors.initials: M
authors.lastname: Yoon
authors.affiliation: Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
authors.forename: Weon Kuu
authors.initials: WK
authors.lastname: Chung
authors.affiliation: Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Kim
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D011878:Radiotherapy / Q000009:adverse effects* / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors
keywords: IMRT; TomoHDA; VMAT; breast; secondary malignancy