RBE-weighted dose in carbon ion therapy for ACC patients

Impact of the RBE model translation on treatment outcomes

Silvia Molinelli, Maria Bonora, Giuseppe Magro, Silvia Casale, Jon Espen Dale, Piero Fossati, Azusa Hasegawa, Alfredo Mirandola, Sara Ronchi, Stefania Russo, Lorenzo Preda, Francesca Valvo, Roberto Orecchia, Mario Ciocca, Barbara Vischioni

Research output: Contribution to journalArticle

Abstract

Purpose/objective: The purpose of this study is to assess the impact of the conversion scheme for relative biological effectiveness (RBE)-weighted dose (DRBE), implemented at our center, on treatment outcomes of adenoid cystic carcinoma (ACC) patients. Material/methods: Treatment plans of 78 ACC patients, optimized with the Local Effect Model (LEM), were recalculated with the modified Microdosimetric Kinetic Model (mMKM). DRBE to 95%, 50% and 2% (DV%) of the clinical target volume (CTV), were selected as relevant parameters to compare LEM and mMKM DRBE. The pattern of failure of ACC treatments was analyzed in relation to uncertainties involved in the DRBE translation methodology. Results: mMKM recalculations of LEM plans, optimized to a prescription dose of 68.8 Gy(RBE), showed a D50% 8% higher, on average, than the expected value (60.8 Gy(RBE)), closer to the most frequently used mMKM prescription DRBE (64 Gy(RBE)). D95% and D2% deviations, with respect to the optimization goals in the two RBE systems, increased of 0.5% and 14.2%, respectively, due to the steeper mMKM RBE variation along the beam path. Local recurrences were mainly (63%) reported in areas where CTV coverage was not satisfactory in the original LEM plan and the mMKM analysis showed that OARs constraints were too conservative. Conclusion: No case of local recurrence could be explained by inadequate mMKM target coverage that was not already present in the LEM plan. New constraints have been defined for optic pathways and brainstem to improve target coverage with no expected increase in tissue complications.

Original languageEnglish
JournalRadiotherapy and Oncology
DOIs
Publication statusAccepted/In press - Jan 1 2019

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Heavy Ion Radiotherapy
Relative Biological Effectiveness
Adenoid Cystic Carcinoma
Biological Models
Prescriptions
Recurrence
Brain Stem
Uncertainty

Keywords

  • Adenoid cystic carcinoma
  • Carbon ion therapy
  • Relative biological effectiveness modeling

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Radiology Nuclear Medicine and imaging

Cite this

RBE-weighted dose in carbon ion therapy for ACC patients : Impact of the RBE model translation on treatment outcomes. / Molinelli, Silvia; Bonora, Maria; Magro, Giuseppe; Casale, Silvia; Dale, Jon Espen; Fossati, Piero; Hasegawa, Azusa; Mirandola, Alfredo; Ronchi, Sara; Russo, Stefania; Preda, Lorenzo; Valvo, Francesca; Orecchia, Roberto; Ciocca, Mario; Vischioni, Barbara.

In: Radiotherapy and Oncology, 01.01.2019.

Research output: Contribution to journalArticle

Molinelli, S, Bonora, M, Magro, G, Casale, S, Dale, JE, Fossati, P, Hasegawa, A, Mirandola, A, Ronchi, S, Russo, S, Preda, L, Valvo, F, Orecchia, R, Ciocca, M & Vischioni, B 2019, 'RBE-weighted dose in carbon ion therapy for ACC patients: Impact of the RBE model translation on treatment outcomes', Radiotherapy and Oncology. https://doi.org/10.1016/j.radonc.2019.08.022
Molinelli, Silvia ; Bonora, Maria ; Magro, Giuseppe ; Casale, Silvia ; Dale, Jon Espen ; Fossati, Piero ; Hasegawa, Azusa ; Mirandola, Alfredo ; Ronchi, Sara ; Russo, Stefania ; Preda, Lorenzo ; Valvo, Francesca ; Orecchia, Roberto ; Ciocca, Mario ; Vischioni, Barbara. / RBE-weighted dose in carbon ion therapy for ACC patients : Impact of the RBE model translation on treatment outcomes. In: Radiotherapy and Oncology. 2019.
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abstract = "Purpose/objective: The purpose of this study is to assess the impact of the conversion scheme for relative biological effectiveness (RBE)-weighted dose (DRBE), implemented at our center, on treatment outcomes of adenoid cystic carcinoma (ACC) patients. Material/methods: Treatment plans of 78 ACC patients, optimized with the Local Effect Model (LEM), were recalculated with the modified Microdosimetric Kinetic Model (mMKM). DRBE to 95{\%}, 50{\%} and 2{\%} (DV{\%}) of the clinical target volume (CTV), were selected as relevant parameters to compare LEM and mMKM DRBE. The pattern of failure of ACC treatments was analyzed in relation to uncertainties involved in the DRBE translation methodology. Results: mMKM recalculations of LEM plans, optimized to a prescription dose of 68.8 Gy(RBE), showed a D50{\%} 8{\%} higher, on average, than the expected value (60.8 Gy(RBE)), closer to the most frequently used mMKM prescription DRBE (64 Gy(RBE)). D95{\%} and D2{\%} deviations, with respect to the optimization goals in the two RBE systems, increased of 0.5{\%} and 14.2{\%}, respectively, due to the steeper mMKM RBE variation along the beam path. Local recurrences were mainly (63{\%}) reported in areas where CTV coverage was not satisfactory in the original LEM plan and the mMKM analysis showed that OARs constraints were too conservative. Conclusion: No case of local recurrence could be explained by inadequate mMKM target coverage that was not already present in the LEM plan. New constraints have been defined for optic pathways and brainstem to improve target coverage with no expected increase in tissue complications.",
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T1 - RBE-weighted dose in carbon ion therapy for ACC patients

T2 - Impact of the RBE model translation on treatment outcomes

AU - Molinelli, Silvia

AU - Bonora, Maria

AU - Magro, Giuseppe

AU - Casale, Silvia

AU - Dale, Jon Espen

AU - Fossati, Piero

AU - Hasegawa, Azusa

AU - Mirandola, Alfredo

AU - Ronchi, Sara

AU - Russo, Stefania

AU - Preda, Lorenzo

AU - Valvo, Francesca

AU - Orecchia, Roberto

AU - Ciocca, Mario

AU - Vischioni, Barbara

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Purpose/objective: The purpose of this study is to assess the impact of the conversion scheme for relative biological effectiveness (RBE)-weighted dose (DRBE), implemented at our center, on treatment outcomes of adenoid cystic carcinoma (ACC) patients. Material/methods: Treatment plans of 78 ACC patients, optimized with the Local Effect Model (LEM), were recalculated with the modified Microdosimetric Kinetic Model (mMKM). DRBE to 95%, 50% and 2% (DV%) of the clinical target volume (CTV), were selected as relevant parameters to compare LEM and mMKM DRBE. The pattern of failure of ACC treatments was analyzed in relation to uncertainties involved in the DRBE translation methodology. Results: mMKM recalculations of LEM plans, optimized to a prescription dose of 68.8 Gy(RBE), showed a D50% 8% higher, on average, than the expected value (60.8 Gy(RBE)), closer to the most frequently used mMKM prescription DRBE (64 Gy(RBE)). D95% and D2% deviations, with respect to the optimization goals in the two RBE systems, increased of 0.5% and 14.2%, respectively, due to the steeper mMKM RBE variation along the beam path. Local recurrences were mainly (63%) reported in areas where CTV coverage was not satisfactory in the original LEM plan and the mMKM analysis showed that OARs constraints were too conservative. Conclusion: No case of local recurrence could be explained by inadequate mMKM target coverage that was not already present in the LEM plan. New constraints have been defined for optic pathways and brainstem to improve target coverage with no expected increase in tissue complications.

AB - Purpose/objective: The purpose of this study is to assess the impact of the conversion scheme for relative biological effectiveness (RBE)-weighted dose (DRBE), implemented at our center, on treatment outcomes of adenoid cystic carcinoma (ACC) patients. Material/methods: Treatment plans of 78 ACC patients, optimized with the Local Effect Model (LEM), were recalculated with the modified Microdosimetric Kinetic Model (mMKM). DRBE to 95%, 50% and 2% (DV%) of the clinical target volume (CTV), were selected as relevant parameters to compare LEM and mMKM DRBE. The pattern of failure of ACC treatments was analyzed in relation to uncertainties involved in the DRBE translation methodology. Results: mMKM recalculations of LEM plans, optimized to a prescription dose of 68.8 Gy(RBE), showed a D50% 8% higher, on average, than the expected value (60.8 Gy(RBE)), closer to the most frequently used mMKM prescription DRBE (64 Gy(RBE)). D95% and D2% deviations, with respect to the optimization goals in the two RBE systems, increased of 0.5% and 14.2%, respectively, due to the steeper mMKM RBE variation along the beam path. Local recurrences were mainly (63%) reported in areas where CTV coverage was not satisfactory in the original LEM plan and the mMKM analysis showed that OARs constraints were too conservative. Conclusion: No case of local recurrence could be explained by inadequate mMKM target coverage that was not already present in the LEM plan. New constraints have been defined for optic pathways and brainstem to improve target coverage with no expected increase in tissue complications.

KW - Adenoid cystic carcinoma

KW - Carbon ion therapy

KW - Relative biological effectiveness modeling

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