PMID- 36535431
OWN - NLM
STAT- MEDLINE
DCOM- 20230320
LR  - 20230511
IS  - 1879-355X (Electronic)
IS  - 0360-3016 (Linking)
VI  - 115
IP  - 5
DP  - 2023 Apr 1
TI  - Predicted Inferior Outcomes for Lung SBRT With Treatment Planning Systems That 
      Fail Independent Phantom-Based Audits.
PG  - 1301-1308
LID - S0360-3016(22)03626-4 [pii]
LID - 10.1016/j.ijrobp.2022.12.003 [doi]
AB  - PURPOSE: More than 15% of radiation therapy clinics fail external audits with 
      anthropomorphic phantoms conducted by Imaging and Radiation Oncology Core-Houston 
      (IROC-H) while passing other industry-standard quality assurance (QA) tests. We 
      seek to evaluate the predicted effect of such failed plans on outcomes for 
      patients treated with stereotactic body radiation therapy (SBRT) for lung tumors. 
      METHODS AND MATERIALS: We conducted a retrospective study of 55 patients treated 
      with SBRT for lung tumors with a prescription biologically equivalent dose 
      (BED)(10) >/=100 Gy using a treatment planning system (TPS) that passed IROC-H 
      phantom audits. Sample linear accelerator beam models with introduced errors were 
      commissioned by varying the multileaf collimator leaf-tip offset parameter (ie, 
      dosimetric leaf gap) over the range +/-1.0 mm relative to the validated model. 
      These models mimic TPS that pass internal QA measures but fail IROC-H tests. 
      Patient plans were recalculated on sample beam models. The predicted tumor 
      control probability (TCP) and normal tissue complication probability (NTCP) were 
      calculated based on published dose-response models. RESULTS: A leaf-tip offset 
      value of -1.0 mm decreased the fraction of plans receiving a planning treatment 
      volume of BED(10) >/=100 Gy from 95% to 27%. This translated to a significant 
      decrease in 2-year TCP of 4.8% (95% CI: 2.0%-5.5%) with a decrease in TCP up to 
      21%. Conversely, a leaf-tip offset of +1.0 mm resulted in 36% of patients 
      exceeding previously met organs at risk (OAR) constraints, including 2 instances 
      of spinal cord and brachial plexus overdoses and a small increase in chest wall 
      NTCP of 0.7%, (95% CI: 0.5%-0.8%). CONCLUSIONS: Simulated treatment plans with 
      modest MLC leaf offsets result in lung SBRT plans that significantly underdose 
      tumor or exceed OAR constraints. These dosimetric endpoints translate to 
      significant detriments in TCP. These simulated plans mimic planning systems that 
      pass internal QA measures but fail independent phantom-based tests, underscoring 
      the need for enhanced quality assurance including external audits of TPS.
CI  - Copyright (c) 2022 Elsevier Inc. All rights reserved.
FAU - Greer, Matthew D
AU  - Greer MD
AD  - University of Washington Department of Radiation Oncology, Seattle, Washington; 
      The University of Arizona Cancer Center, Tucson, Arizona. Electronic address: 
      mdgreer@arizona.edu.
FAU - Koger, Brandon
AU  - Koger B
AD  - University of Pennsylvania Department of Radiation Oncology, Philadelphia, 
      Pennsylvania.
FAU - Glenn, Mallory
AU  - Glenn M
AD  - University of Washington Department of Radiation Oncology, Seattle, Washington.
FAU - Kang, John
AU  - Kang J
AD  - University of Washington Department of Radiation Oncology, Seattle, Washington.
FAU - Rengan, Ramesh
AU  - Rengan R
AD  - University of Washington Department of Radiation Oncology, Seattle, Washington.
FAU - Zeng, Jing
AU  - Zeng J
AD  - University of Washington Department of Radiation Oncology, Seattle, Washington.
FAU - Ford, Eric
AU  - Ford E
AD  - University of Washington Department of Radiation Oncology, Seattle, Washington.
LA  - eng
PT  - Journal Article
DEP - 20221216
PL  - United States
TA  - Int J Radiat Oncol Biol Phys
JT  - International journal of radiation oncology, biology, physics
JID - 7603616
SB  - IM
MH  - Humans
MH  - *Radiosurgery/methods
MH  - Radiotherapy Dosage
MH  - Retrospective Studies
MH  - Radiotherapy Planning, Computer-Assisted/methods
MH  - *Radiotherapy, Intensity-Modulated/methods
MH  - *Lung Neoplasms/diagnostic imaging/radiotherapy/surgery
MH  - Lung/diagnostic imaging
EDAT- 2022/12/20 06:00
MHDA- 2023/03/21 06:00
CRDT- 2022/12/19 19:24
PHST- 2022/03/31 00:00 [received]
PHST- 2022/10/07 00:00 [revised]
PHST- 2022/12/05 00:00 [accepted]
PHST- 2022/12/20 06:00 [pubmed]
PHST- 2023/03/21 06:00 [medline]
PHST- 2022/12/19 19:24 [entrez]
AID - S0360-3016(22)03626-4 [pii]
AID - 10.1016/j.ijrobp.2022.12.003 [doi]
PST - ppublish
SO  - Int J Radiat Oncol Biol Phys. 2023 Apr 1;115(5):1301-1308. doi: 
      10.1016/j.ijrobp.2022.12.003. Epub 2022 Dec 16.