Large anatomical changes in head-and-neck cancers – A dosimetric comparison of online and offline adaptive proton therapy

Bobić, Mislav; Lalonde, Arthur; Nesteruk, Konrad Pawel; Lee, Hoyeon; Nenoff, Lena; Gorissen, Bram L.; Bertolet, Alejandro; Busse, Paul M.; Chan, Annie W.; Winey, B.; Sharp, G; Verburg, J; Lomax, Anthony; Paganetti, Harald

doi:10.1016/j.ctro.2023.100625

Cited by 12 publications

(16 citation statements)

References 43 publications

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“…Furthermore, our choice of a 1.5 mm setup margin for online adaptation aligns with a very recent dosimetry study on HN proton therapy by Bobić et al. 36 in which they used a 4 mm setup margin for offline replanning and a 1 mm setup margin for online replanning. Using a smaller setup margin for online adaptation was also suggested in multiple other studies on adaptive radiotherapy 37 , 38 A recent review paper by Huiskes et al.…”

Section: Discussionmentioning

confidence: 56%

A retrospective study on the investigation of potential dosimetric benefits of online adaptive proton therapy for head and neck cancer

Chang,

Bohannon,

Tian

et al. 2024

J Applied Clin Med Phys

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PurposeProton therapy is sensitive to anatomical changes, often occurring in head‐and‐neck (HN) cancer patients. Although multiple studies have proposed online adaptive proton therapy (APT), there is still a concern in the radiotherapy community about the necessity of online APT. We have performed a retrospective study to investigate the potential dosimetric benefits of online APT for HN patients relative to the current offline APT.MethodsOur retrospective study has a patient cohort of 10 cases. To mimic online APT, we re‐evaluated the dose of the in‐use treatment plan on patients’ actual treatment anatomy captured by cone‐beam CT (CBCT) for each fraction and performed a templated‐based automatic replanning if needed, assuming that these were performed online before treatment delivery. Cumulative dose of the simulated online APT course was calculated and compared with that of the actual offline APT course and the designed plan dose of the initial treatment plan (referred to as nominal plan). The ProKnow scoring system was employed and adapted for our study to quantify the actual quality of both courses against our planning goals.ResultsThe average score of the nominal plans over the 10 cases is 41.0, while those of the actual offline APT course and our simulated online course is 25.8 and 37.5, respectively. Compared to the offline APT course, our online course improved dose quality for all cases, with the score improvement ranging from 0.4 to 26.9 and an average improvement of 11.7.ConclusionThe results of our retrospective study have demonstrated that online APT can better address anatomical changes for HN cancer patients than the current offline replanning practice. The advanced artificial intelligence based automatic replanning technology presents a promising avenue for extending potential benefits of online APT.

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Section: Discussionmentioning

confidence: 56%

A retrospective study on the investigation of potential dosimetric benefits of online adaptive proton therapy for head and neck cancer

Chang,

Bohannon,

Tian

et al. 2024

J Applied Clin Med Phys

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“…The selected setup robustness setting of 3 mm for offline TB re-planning is the same as currently used in our clinic. The 1 mm setup robustness setting for online re-optimization was based on literature (Nenoff et al 2021, Bobić et al 2023. Both for CTV 7000 and for CTV 5425 , generated treatment plans had to meet a coverage constraint: V 95% > 98% in the voxelwise minimum dose distribution (Korevaar et al 2019).…”

Section: Full Multi-criterial Optimization Of Treatment Plansmentioning

confidence: 99%

“…This has not yet been employed to evaluate plan adaptation strategies, (2) no comparison with current state-of-the-art clinical treatment planning strategy, such as robust optimization with trigger-based offline adaptive re-planning. Bobić et al (2023) compared their online re-optimization strategy to their clinical offline adaptation strategy. However, robustness evaluation was not performed and they exclusively included patients that needed an offline adaptation, not providing a representative sample of the patient population.…”

Section: Introductionmentioning

confidence: 99%

A fast and robust constraint-based online re-optimization approach for automated online adaptive intensity modulated proton therapy in head and neck cancer

Oud,

Breedveld,

Rojo-Santiago

et al. 2024

Phys. Med. Biol.

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Objective – In head-and-neck cancer intensity modulated proton therapy (IMPT), adaptive radiotherapy is currently restricted to offline re-planning, mitigating the effect of slow changes in patient anatomies. Daily online adaptations can potentially improve dosimetry. Here, a new, fully automated online re-optimization strategy is presented. In a retrospective study, this online re-optimization approach was compared to our trigger-based offline re-planning (offlineTB re-planning) schedule, including extensive robustness analyses.Approach – The online re-optimization method employs automated multi-criterial re-optimization, using robust optimization with 1 mm setup-robustness settings (in contrast to 3 mm for offlineTB re-planning). Hard planning constraints and spot addition are used to enforce adequate target coverage, avoid prohibitively large maximum doses and minimize organ-at-risk doses. For 67 repeat-CTs from 15 patients, fraction doses of the two strategies were compared for the CTVs and organs-at-risk. Per repeat-CT, 10.000 fractions with different setup and range robustness settings were simulated using Polynomial Chaos Expansion for fast and accurate dose calculations. Main results – For 14/67 repeat-CTs, offlineTB re-planning resulted in <50% probability of D98%≥95% of the prescribed dose (Dpres) in one or both CTVs, which never happened with online re-optimization. With offlineTB re-planning, eight repeat-CTs had zero probability of obtaining D98%≥95%Dpres for CTV7000, while the minimum probability with online re-optimization was 81%. Risks of xerostomia and dysphagia grade ≥ II were reduced by 3.5 ± 1.7 and 3.9 ± 2.8 percentage point [mean ± SD] (p<10-5 for both). In online re-optimization, adjustment of spot configuration followed by spot-intensity re-optimization took 3.4 minutes on average. Significance – The fast online re-optimization strategy always prevented substantial losses of target coverage caused by day-to-day anatomical variations, as opposed to the clinical trigger-based offline re-planning schedule. On top of this, online re-optimization could be performed with smaller setup robustness settings, contributing to improved organs-at-risk sparing.

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“…As detailed in the following section, patient-specific results associated with each scenario were intercompared rather than analyzed individually, this to assess the specific impact on NTCP of SUR alone, AGC alone as well as SUR and AGC combined. For scenario C, OA of the treatment plans was done using a constrained spot-intensity re-optimization approach developed within our group and detailed in previous publications (Lalonde et al 2021, 2023. This method restores the plan quality by only re-optimizing the weights of a subset of highly weighted proton beamlets, without modifying their position or energy.…”

Section: Dose Accumulation and Oamentioning

confidence: 99%

“…However, gains in plan robustness are often achieved at the cost of an increase in NTCP (Van De Water et al 2016 ), potentially compromising the benefits of IMPT. As an alternative, online adaptive proton therapy workflows have been proposed by different groups (Da Silva et al 2015 , Jagt et al 2017 , Botas et al 2018 , Matter et al 2019 , Lalonde et al 2021 , Paganetti et al 2021 , Bobić et al 2021 , 2023 ). Online adaptation (OA) corrects for anatomical changes and setup variations by adapting the treatment plan just before delivering each fraction, using either a fast re-optimization (Botas et al 2018 , Matter et al 2019 , Lalonde et al 2021 , Paganetti et al 2021 , Bobić et al 2021 , 2023 ) or dose restoration (Da Silva et al 2015 , Jagt et al 2017 , Bernatowicz et al 2018 ) technique.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the effect of setup uncertainty reduction and adaptation to geometric changes on normal tissue complication probability using online adaptive head and neck intensity modulated proton therapy

et al. 2023

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Objective: To evaluate the impact of setup uncertainty reduction (SUR) and adaptation to geometrical changes (AGC) on normal tissue complication probability (NTCP) when using online adaptive head and neck intensity modulated proton therapy (IMPT).Approach: A cohort of ten retrospective head and neck cancer patients with daily scatter corrected cone-beam CT (CBCT) was studied. For each patient, two IMPT treatment plans were created: one with a 3-mm setup uncertainty robustness setting and one with no explicit setup robustness. Both plans were recalculated on the daily CBCT considering three scenarios: the robust plan without adaptation, the non-robust plan without adaptation and the non-robust plan with daily online adaptation. Online-adaptation was simulated using an in-house developed workflow based on GPU-accelerated Monte Carlo dose calculation and partial spot-intensity re-optimization. Dose distributions associated with each scenario were accumulated on the planning CT, where NTCP models for six toxicities were applied. NTCP values from each scenario were intercompared to quantify the reduction in toxicity risk induced by SUR alone, AGC alone and SUR and AGC combined. Finally, a decision tree was implemented to assess the clinical significance of the toxicity reduction associated with each mechanism.Main results: For most patients, clinically meaningful NTCP reductions were only achieved when SUR and AGC were performed together. In these conditions, total reductions in NTCP of up to 30.48 pp were obtained, with noticeable NTCP reductions for aspiration, dysphagia and xerostomia (mean reductions of 8.25, 5.42 and 5.12 pp respectively). While SUR had a generally larger impact than AGC on NTCP reductions, SUR alone did not induce clinically meaningful toxicity reductions in any patient, compared to only one for AGC alone.Significance: Online adaptive head and neck proton therapy can only yield clinically significant reductions in the risk of long-term side effects when combining the benefits of SUR and AGC.

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Large anatomical changes in head-and-neck cancers – A dosimetric comparison of online and offline adaptive proton therapy

Cited by 12 publications

References 43 publications

A retrospective study on the investigation of potential dosimetric benefits of online adaptive proton therapy for head and neck cancer

A retrospective study on the investigation of potential dosimetric benefits of online adaptive proton therapy for head and neck cancer

A fast and robust constraint-based online re-optimization approach for automated online adaptive intensity modulated proton therapy in head and neck cancer

Evaluating the effect of setup uncertainty reduction and adaptation to geometric changes on normal tissue complication probability using online adaptive head and neck intensity modulated proton therapy

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