Adaptive Image-Guided Radiotherapy (IGRT) Eliminates the Risk of Biochemical Failure Caused by the Bias of Rectal Distension in Prostate Cancer Treatment Planning: Clinical Evidence

Park, Sean S.; Yan, Di; McGrath, Samuel; Dilworth, J.T.; Liang, Jian; Ye, Hong; Krauss, Daniel; Martínez, Álvaro; Kestin, Larry L.

doi:10.1016/j.ijrobp.2011.08.025

Cited by 57 publications

(44 citation statements)

References 18 publications

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“…ART had been used clinically for prostate cancer since 1997, with a total of 1269 patients reported as treated at six different institutions [11,12,[13][14][15][16][17][18][19][20][21]. For the reviewed studies reporting CTV extension, the volume included prostate only in 405 patients, prostate and parts of the seminal vesicles in 649 patients and prostate, seminal vesicles and pelvic lymph nodes in one patient.…”

Section: Prostate Cancermentioning

confidence: 99%

“…The adaptation strategy and timing applied to the majority (1186) of the prostate patients was offline re-plan/re-optimization after the initial 1-2 weeks of treatment to adjust to patient-specific prostate motion relative to bony anatomy ( Table 2, Figures 2 and 3) [11][12][13][14][15][16][17][18]. This ART strategy was used in three single institutional studies.…”

Section: Prostate Cancermentioning

confidence: 99%

“…This ART strategy was used in three single institutional studies. The earliest implementations, and the pioneers of ART for prostate cancer, were conducted at Beaumont Hospital, US, where 962 patients were treated between the years 1997-2006 [9][10][11][12][13][14][15][16]22]. The target treated was prostate only for 42% of the patients with the remaining 58% receiving irradiation of both prostate and seminal vesicles.…”

Section: Prostate Cancermentioning

confidence: 99%

“…Their initial implementation, applied to 10 patients, was based on field adjustments for adaptation to the patient-specific set-up errors detected by mega-voltage (MV) radiographs [13]. Subsequently, the workflow was expanded to adaptation of target shape changes through construction of a patient-specific planning target volume (PTV) and finally -for the majority of the patients -this PTV was used for individualized dose escalations until reaching the pre-set criteria for rectum and bladder constraints (Table 2) [11][12][13][14][15][16]22]. The patient-specific PTV, adapted target motion in regard to bony anatomy and was composed of a union formed from four delineated target volumes in the initial CTs to account for shape -and positional changes.…”

Section: Prostate Cancermentioning

confidence: 99%

“…Outcome and/or toxicity data has only been reported by the Beaumont group, with 96% bio-chemical control after five years for the low-risk (prostate only) and 83% for the higher risk groups [16]. Acute rectal toxicity Grade 2 [Common Terminology Criteria (CTC) 2.0] was 34%, presented for a subgroup of 331 patients [15].…”

Section: Prostate Cancermentioning

confidence: 99%

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Adaptive radiotherapy strategies for pelvic tumors – a systematic review of clinical implementations

et al. 2016

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Section: Prostate Cancermentioning

confidence: 99%

Section: Prostate Cancermentioning

confidence: 99%

Section: Prostate Cancermentioning

confidence: 99%

Section: Prostate Cancermentioning

confidence: 99%

Section: Prostate Cancermentioning

confidence: 99%

See 3 more Smart Citations

Adaptive radiotherapy strategies for pelvic tumors – a systematic review of clinical implementations

et al. 2016

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Prospects for daily online adaptive radiotherapy via ethos for prostate cancer patients without nodal involvement using unedited CBCT auto‐segmentation

Moazzezi

Rose

Kisling

et al. 2021

J Applied Clin Med Phys

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Implementing new online adaptive radiation therapy technologies is challenging because extra clinical resources are required particularly expert contour review. Here, we provide the first assessment of Varian's Ethos™ adaptive platform for prostate cancer using no manual edits after auto-segmentation to minimize this impact on clinical efficiency. Methods: Twenty-five prostate patients previously treated at our clinic were re-planned using an Ethos™ emulator. Clinical target volumes (CTV) included intact prostate and proximal seminal vesicles. The following clinical margins were used: 3 mm posterior, 5 mm left/right/anterior, and 7 mm superior/inferior. Adapted plans were calculated for 10 fractions per patient using Ethos's autosegmentation and auto-planning workflow without manual contouring edits. Doses and auto-segmented structures were exported to our clinical treatment planning system where contours were modified as needed for all 250 CTVs and organs-at-risk. Dose metrics from adapted plans were compared to unadapted plans to evaluate CTV and OAR dose changes. Results: Overall 96% of fractions required auto-segmentation edits, although corrections were generally minor (<10% of the volume for 70% of CTVs, 88% of bladders, and 90% of rectums). However, for one patient the autosegmented CTV failed to include the superior portion of prostate that extended into the bladder at all 10 fractions resulting in under-contouring of the CTV by 31.3% ± 6.7%. For the 24 patients with minor auto-segmentation corrections, adaptation improved CTV D98% by 2.9% ± 5.3%. For non-adapted fractions where bladder or rectum V90% exceeded clinical thresholds, adaptation reduced them by 13.1% ± 1.0% and 6.5% ± 7.3%, respectively. Conclusion: For most patients, Ethos's online adaptive radiation therapy workflow improved CTV D98% and reduced normal tissue dose when structures would otherwise exceed clinical thresholds, even without time-consuming manual edits. However, for one in 25 patients, large contour edits were required and thus scrutiny of the daily auto-segmentation is necessary and not all patients will be good candidates for adaptation.

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Clinical commissioning of an adaptive radiotherapy platform: Results and recommendations

Kisling

Keiper

Branco

et al. 2022

J Applied Clin Med Phys

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Online adaptive radiotherapy platforms present a unique challenge for commissioning as guidance is lacking and specialized adaptive equipment, such as deformable phantoms, are rare. We designed a novel adaptive commissioning process consisting of end‐to‐end tests using standard clinical resources. These tests were designed to simulate anatomical changes regularly observed at patient treatments. The test results will inform users of the magnitude of uncertainty from on‐treatment changes during the adaptive workflow and the limitations of their systems. We implemented these tests for the cone‐beam computed tomography (CT)‐based Varian Ethos online adaptive platform. Many adaptive platforms perform online dose calculation on a synthetic CT (synCT). To assess the impact of the synCT generation and online dose calculation on dosimetric accuracy, we conducted end‐to‐end tests using commonly available equipment: a CIRS IMRT Thorax phantom, PinPoint ionization chamber, Gafchromic film, and bolus. Four clinical scenarios were evaluated: weight gain and weight loss were simulated by adding and removing bolus, internal target shifts were simulated by editing the CTV during the adaptive workflow to displace it, and changes in gas were simulated by removing and reinserting rods in varying phantom locations. The effect of overriding gas pockets during planning was also assessed. All point dose measurements agreed within 2.7% of the calculated dose, with one exception: a scenario simulating gas present in the planning CT, not overridden during planning, and dissipating at treatment. Relative film measurements passed gamma analysis (3%/3 mm criteria) for all scenarios. Our process validated the Ethos dose calculation for online adapted treatment plans. Based on our results, we made several recommendations for our clinical adaptive workflow. This commissioning process used commonly available equipment and, therefore, can be applied in other clinics for their respective online adaptive platforms.

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Adaptive Image-Guided Radiotherapy (IGRT) Eliminates the Risk of Biochemical Failure Caused by the Bias of Rectal Distension in Prostate Cancer Treatment Planning: Clinical Evidence

Cited by 57 publications

References 18 publications

Adaptive radiotherapy strategies for pelvic tumors – a systematic review of clinical implementations

Adaptive radiotherapy strategies for pelvic tumors – a systematic review of clinical implementations

Prospects for daily online adaptive radiotherapy via ethos for prostate cancer patients without nodal involvement using unedited CBCT auto‐segmentation

Clinical commissioning of an adaptive radiotherapy platform: Results and recommendations

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