Comparison of organ‐at‐risk sparing and plan robustness for spot‐scanning proton therapy and volumetric modulated arc photon therapy in head‐and‐neck cancer

Over the last few decades, significant improvements have been made in the radiotherapy (RT) treatment of head and neck malignancies. The progressive introduction of intensity-modulated RT and the use of multimodality imaging for target volume and organs at risk delineation, together with the use of altered fractionation regimens and concomitant administration of chemotherapy or targeted agents, have accompanied efficacy improvements in RT. Altogether, such improvements have translated into improvement in locoregional control and overall survival probability, with a decrease in the long-term adverse effects of RT and an improvement in quality of life. Further progress in the treatment of head and neck malignancies may come from a better integration of molecular imaging to identify tumor subvolumes that may require additional radiation doses (ie, dose painting) and from treatment adaptation tracing changes in patient anatomy during treatment. Proton therapy generates even more exquisite dose distribution in some patients, thus potentially further improving patient outcomes. However, the clinical benefit of these approaches, although promising, for patients with head and neck cancer need to be demonstrated in prospective randomized studies. In this context, our article will review some of these advances, with special emphasis on target volume and organ-at-risk delineation, use of molecular imaging for tumor delineation, dose painting for dose escalation, dose adaptation throughout treatment, and potential benefit of proton therapy.

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PD-0052: Interobserver variability in organ at risk delineation in head and neck cancer

Radiotherapy and Oncology ◽

10.1016/s0167-8140(21)00078-5 ◽

2020 ◽

Vol 152 ◽

pp. S19-S20

Author(s):

J. Van der Veen ◽

A. Gulyban ◽

S. Willems ◽

F. Maes ◽

S. Nuyts

Keyword(s):

At Risk ◽

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Interobserver Variability ◽

Organ At Risk

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Interobserver variability in organ at risk delineation in head and neck cancer.

10.21203/rs.3.rs-39575/v2 ◽

2020 ◽

Author(s):

Julie van der Veen ◽

Akos Gulyban ◽

Siri Willems ◽

Frederik Maes ◽

Sandra Nuyts

Keyword(s):

Artificial Intelligence ◽

At Risk ◽

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Interobserver Variability ◽

Treatment Plan ◽

Consensus Guidelines ◽

International Consensus ◽

Organ At Risk

Abstract Background: In radiotherapy inaccuracy in organ at risk (OAR) delineation can impact treatment plan optimisation and treatment plan evaluation. Brouwer et al. showed significant interobserver variability (IOV) in OAR delineation in head and neck cancer (HNC) and published international consensus guidelines (ICG) for OAR delineation in 2015. The aim of our study was to evaluate IOV in the presence of these guidelines. Methods: HNC radiation oncologists (RO) from each Belgian radiotherapy centre were invited to complete a survey and submit contours for 5 HNC cases. Reference contours (OARref) were obtained by a clinically validated artificial intelligence-tool trained using ICG. Dice similarity coefficients (DSC), mean surface distance (MSD) and 95% Hausdorff distances (HD95) were used for comparison.Results: Fourteen of twenty-two RO (64%) completed the survey and submitted delineations. Thirteen (93%) confirmed the use of delineation guidelines, of which six (43%) used the ICG. The OARs whose delineations agreed best with the OARref were mandible (median DSC 0.9, range [0.8-0.9]; median MSD 1.1mm, range [0.8-8.3], median HD95 3.4mm, range [1.5-38.7]), brainstem (median DSC 0.9 [0.6-0.9]; median MSD 1.5mm [1.1-4.0], median HD95 4.0mm [2.3-15.0]), submandibular glands (median DSC 0.8 [0.5-0.9]; median MSD 1.2mm [0.9-2.5], median HD95 3.1mm [1.8-12.2]) and parotids (median DSC 0.9 [0.6-0.9]; median MSD 1.9mm [1.2-4.2], median HD95 5.1mm [3.1-19.2]). Oral cavity, cochleas, PCMs, supraglottic larynx and glottic area showed more variation. RO who used the consensus guidelines showed significantly less IOV (p=0.008).Conclusion: Although ICG for delineation of OARs in HNC exist, they are only implemented by about half of RO participating in this study, which partly explains the delineation variability. However, this study highlights that guidelines alone do not suffice to eliminate IOV and that more effort needs to be done to accomplish further treatment standardisation, for example with artificial intelligence.

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Prospective randomized double-blind study of atlas-based organ-at-risk autosegmentation-assisted radiation planning in head and neck cancer

Radiotherapy and Oncology ◽

10.1016/j.radonc.2014.08.028 ◽

2014 ◽

Vol 112 (3) ◽

pp. 321-325 ◽

Cited By ~ 43

Author(s):

Gary V. Walker ◽

Musaddiq Awan ◽

Randa Tao ◽

Eugene J. Koay ◽

Nicholas S. Boehling ◽

...

Keyword(s):

At Risk ◽

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Blind Study ◽

Double Blind Study ◽

Double Blind ◽

Organ At Risk ◽

Radiation Planning

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Interobserver Variability in Organ at Risk Delineation in Head and Neck Cancer.

10.21203/rs.3.rs-39575/v1 ◽

2020 ◽

Author(s):

Julie van der Veen ◽

Akos Gulyban ◽

Siri Willems ◽

Frederik Maes ◽

Sandra Nuyts

Keyword(s):

Artificial Intelligence ◽

At Risk ◽

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Interobserver Variability ◽

Treatment Plan ◽

Consensus Guidelines ◽

International Consensus ◽

Organ At Risk

Abstract Background: In radiotherapy inaccuracy in organ at risk (OAR) delineation can impact treatment plan optimisation and treatment plan evaluation. Brouwer et al. showed significant interobserver variability (IOV) in OAR delineation in head and neck cancer (HNC) and published international consensus guidelines (ICG) for OAR delineation in 2015. The aim of our study was to evaluate IOV in the presence of these guidelines. Methods: HNC radiation oncologists (RO) from each Belgian radiotherapy centre were invited to complete a survey and submit contours for 5 HNC cases. Reference contours (OARref) were obtained by a clinically validated artificial intelligence-tool trained using ICG. Dice similarity coefficients (DSC), mean surface distance (MSD) and 95% Hausdorff distances (HD95) were used for comparison.Results: Fourteen of twenty-two RO (64%) completed the survey and submitted delineations. Thirteen (93%) confirmed the use of delineation guidelines, of which six (43%) used the ICG. The OARs whose delineations agreed best with the OARref were mandible (median DSC 0.9, range [0.8-0.9]; median MSD 1.1mm, range [0.8-8.3], median HD95 3.4mm, range [1.5-38.7]), brainstem (median DSC 0.9 [0.6-0.9]; median MSD 1.5mm [1.1-4.0], median HD95 4.0mm [2.3-15.0]), submandibular glands (median DSC 0.8 [0.5-0.9]; median MSD 1.2mm [0.9-2.5], median HD95 3.1mm [1.8-12.2]) and parotids (median DSC 0.9 [0.6-0.9]; median MSD 1.9mm [1.2-4.2], median HD95 5.1mm [3.1-19.2]). Oral cavity, cochleas, PCMs, supraglottic larynx and glottic area showed more variation. RO who used the consensus guidelines showed significantly less IOV (p=0.008).Conclusion: Although ICG for delineation of OARs in HNC exist, they are only implemented by about half of RO participating in this study, which partly explains the delineation variability. However, this study highlights that guidelines alone do not suffice to eliminate IOV and that more effort needs to be done to accomplish further treatment standardisation, for example with artificial intelligence.

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