Hypofractionation of partial breast irradiation using radiobiological models

Michele Avanzo, Marco Trovo, Joseph Stancanello, Rajesh Jena, Mario Roncadin, Giulia Toffoli, Chiara Zuiani, Elvira Capra

Research output: Contribution to journalArticle

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Abstract

Purpose: To reduce the fraction number in Partial Breast Irradiation (PBI) with initial prescription of 40 Gy in 10 fractions using radiobiological models with specific focus on risk of moderate/severe radiation-induced fibrosis (RIF) and report clinical results. Methods and materials: 68 patients (patient group A) were treated with 40 Gy in 10 fractions delivered by field-in-field, forward-planned IMRT. Isotoxic regimens with decreasing number of fractions were calculated using Biological Effective Dose (BED) to the breast. Risk for RIF in hypofractionated treatment was predicted by calculating NTCP from DVHs of group A rescaled to fractions and dose of novel regimens. Moderate/severe RIF was prospectively scored during follow-up. Various NTCP models, with and without incomplete repair correction, were assessed from difference to observed incidence of RIF. In order to verify the value for α/β of 3 Gy assumed for breast, we fitted α/β to observed incidences of moderate/severe RIF. Results: Treatments with 35 Gy/7f and 28 Gy/4f were selected for the fraction reduction protocol. 75 patients (group B) were treated in 35 Gy/7f. Incidence of moderate/severe RIF was 5.9% in group A, 5.3% in group B. The NTCP model with correction for incomplete repair had lowest difference from observed RIF. The α/β obtained from fitting was 2.8 (95%CIs 1.1-10.7) Gy. Conclusions: The hypofractionated regimen was well tolerated. The model for NTCP corrected for incomplete repair was the most accurate and an assumed α/β value of 3 Gy is consistent with our patient data. The hypofractionation protocol is continuing with patients treated with 28 Gy/4f.

Original languageEnglish
Pages (from-to)1022-1028
Number of pages7
JournalPhysica Medica
Volume31
Issue number8
DOIs
Publication statusPublished - Dec 1 2015

Fingerprint

Radiation Pneumonitis
fibrosis
breast
Breast
irradiation
radiation
incidence
Incidence
dosage
Prescriptions
Therapeutics

Keywords

  • Breast
  • Fibrosis
  • Hypofractionation
  • NTCP
  • Partial breast irradiation
  • TCP

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging
  • Physics and Astronomy(all)

Cite this

Avanzo, M., Trovo, M., Stancanello, J., Jena, R., Roncadin, M., Toffoli, G., ... Capra, E. (2015). Hypofractionation of partial breast irradiation using radiobiological models. Physica Medica, 31(8), 1022-1028. https://doi.org/10.1016/j.ejmp.2015.08.016

Hypofractionation of partial breast irradiation using radiobiological models. / Avanzo, Michele; Trovo, Marco; Stancanello, Joseph; Jena, Rajesh; Roncadin, Mario; Toffoli, Giulia; Zuiani, Chiara; Capra, Elvira.

In: Physica Medica, Vol. 31, No. 8, 01.12.2015, p. 1022-1028.

Research output: Contribution to journalArticle

Avanzo, M, Trovo, M, Stancanello, J, Jena, R, Roncadin, M, Toffoli, G, Zuiani, C & Capra, E 2015, 'Hypofractionation of partial breast irradiation using radiobiological models', Physica Medica, vol. 31, no. 8, pp. 1022-1028. https://doi.org/10.1016/j.ejmp.2015.08.016
Avanzo M, Trovo M, Stancanello J, Jena R, Roncadin M, Toffoli G et al. Hypofractionation of partial breast irradiation using radiobiological models. Physica Medica. 2015 Dec 1;31(8):1022-1028. https://doi.org/10.1016/j.ejmp.2015.08.016
Avanzo, Michele ; Trovo, Marco ; Stancanello, Joseph ; Jena, Rajesh ; Roncadin, Mario ; Toffoli, Giulia ; Zuiani, Chiara ; Capra, Elvira. / Hypofractionation of partial breast irradiation using radiobiological models. In: Physica Medica. 2015 ; Vol. 31, No. 8. pp. 1022-1028.
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abstract = "Purpose: To reduce the fraction number in Partial Breast Irradiation (PBI) with initial prescription of 40 Gy in 10 fractions using radiobiological models with specific focus on risk of moderate/severe radiation-induced fibrosis (RIF) and report clinical results. Methods and materials: 68 patients (patient group A) were treated with 40 Gy in 10 fractions delivered by field-in-field, forward-planned IMRT. Isotoxic regimens with decreasing number of fractions were calculated using Biological Effective Dose (BED) to the breast. Risk for RIF in hypofractionated treatment was predicted by calculating NTCP from DVHs of group A rescaled to fractions and dose of novel regimens. Moderate/severe RIF was prospectively scored during follow-up. Various NTCP models, with and without incomplete repair correction, were assessed from difference to observed incidence of RIF. In order to verify the value for α/β of 3 Gy assumed for breast, we fitted α/β to observed incidences of moderate/severe RIF. Results: Treatments with 35 Gy/7f and 28 Gy/4f were selected for the fraction reduction protocol. 75 patients (group B) were treated in 35 Gy/7f. Incidence of moderate/severe RIF was 5.9{\%} in group A, 5.3{\%} in group B. The NTCP model with correction for incomplete repair had lowest difference from observed RIF. The α/β obtained from fitting was 2.8 (95{\%}CIs 1.1-10.7) Gy. Conclusions: The hypofractionated regimen was well tolerated. The model for NTCP corrected for incomplete repair was the most accurate and an assumed α/β value of 3 Gy is consistent with our patient data. The hypofractionation protocol is continuing with patients treated with 28 Gy/4f.",
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