Modeling Dose Response for Late Dysphagia in Patients With Head and Neck Cancer in the Modern Era of Definitive Chemoradiation

Radiation Therapy for HPV-Positive Oropharyngeal Squamous Cell Carcinoma: An ASTRO Clinical Practice Guideline

PURPOSE

Human Papilloma Virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is a distinct disease from other head and neck tumors. This guideline provides evidence-based recommendations on the critical decisions in its curative treatment, including both definitive and postoperative radiation therapy (RT) management.

METHODS

ASTRO convened a task force to address 5 key questions on the use of RT for management of HPV-associated OPSCC. These questions included indications for definitive and postoperative RT and chemoradiation; dose-fractionation regimens and treatment volumes; preferred RT techniques and normal tissue considerations; and posttreatment management decisions. The task force did not address indications for primary surgery versus RT. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Concurrent cisplatin is recommended for patients receiving definitive RT with T3-4 disease and/or 1 node >3 cm, or multiple nodes. For similar patients who are ineligible for cisplatin, concurrent cetuximab, carboplatin/5-fluorouracil, or taxane-based systemic therapy are conditionally recommended. In the postoperative setting, RT with concurrent cisplatin (either schedule) is recommended for positive surgical margins or extranodal extension. Postoperative RT alone is recommended for pT3-4 disease, >2 nodes, or a single node >3 cm. Observation is conditionally recommended for pT1-2 disease and a single node ≤3 cm without other risk factors. For patients treated with definitive RT with concurrent systemic therapy, 7000 cGy in 33 to 35 fractions is recommended, and for patients receiving postoperative RT without positive surgical margins and extranodal extension, 5600 to 6000 cGy is recommended. For all patients receiving RT, intensity modulated RT over 3-dimensional techniques with reduction in dose to critical organs at risk (including salivary and swallowing structures) is recommended. Reassessment with positron emission tomography-computed tomography is recommended approximately 3 months after definitive RT/chemoradiation, and neck dissection is recommended for convincing evidence of residual disease; for equivocal positron emission tomography-computed tomography findings, either neck dissection or repeat imaging is recommended.

CONCLUSIONS

The role and practice of RT continues to evolve for HPV-associated OPSCC, and these guidelines inform best clinical practice based on the available evidence.

Pharyngeal Constrictor Dose-Volume Histogram Metrics and Patient-Reported Dysphagia in Head and Neck Radiotherapy

AIMS

Head and neck radiotherapy long-term survival continues to improve and the management of long-term side-effects is moving to the forefront of patient care. Dysphagia is associated with dose to the pharyngeal constrictors and can be measured using patient-reported outcomes to evaluate its effect on quality of life. The aim of the present study was to relate pharyngeal constrictor dose-volume parameters with patient-reported outcomes to identify prognostic dose constraints.

MATERIALS AND METHODS

A 64-patient training cohort and a 24-patient testing cohort of oropharynx and nasopharynx cancer patients treated with curative-intent chemoradiotherapy were retrospectively examined. These patients completed the MD Anderson Dysphagia Inventory outcome survey at 12 months post-radiotherapy to evaluate late dysphagia: a composite score lower than 60 indicated dysphagia. The pharyngeal constrictor muscles were subdivided into four substructures: superior, middle, inferior and cricopharyngeal. Dose-volume histogram (DVH) metrics for each of the structure combinations were extracted. A decision tree classifier was run for each DVH metric to identify dose constraints optimising the accuracy and sensitivity of the cohort. A 60% accuracy threshold and feature selection method were used to ensure statistically significant DVH metrics were identified. These dose constraints were then validated on the 24-patient testing cohort.

RESULTS

Existing literature dose constraints only had two dose constraints performing above 60% accuracy and sensitivity when evaluated on our training cohort. We identified two well-performing dose constraints: the pharyngeal constrictor muscle D63% < 55 Gy and the superior-middle pharyngeal constrictor combination structure V31Gy < 100%. Both dose constraints resulted in ≥73% mean accuracy and ≥80% mean sensitivity on the training and testing patient cohorts. In addition, a pharyngeal constrictor muscle mean dose <57 Gy resulted in a mean accuracy ≥74% and mean sensitivity ≥60%.

CONCLUSION

Mid-dose pharyngeal constrictor muscle and substructure combination dose constraints should be used in the treatment planning process to reduce late patient-reported dysphagia.

Prospectively-validated deep learning model for segmenting swallowing and chewing structures in CT

Objective.Delineating swallowing and chewing structures aids in radiotherapy (RT) treatment planning to limit dysphagia, trismus, and speech dysfunction. We aim to develop an accurate and efficient method to automate this process.Approach.CT scans of 242 head and neck (H&N) cancer patients acquired from 2004 to 2009 at our institution were used to develop auto-segmentation models for the masseters, medial pterygoids, larynx, and pharyngeal constrictor muscle using DeepLabV3+. A cascaded framework was used, wherein models were trained sequentially to spatially constrain each structure group based on prior segmentations. Additionally, an ensemble of models, combining contextual information from axial, coronal, and sagittal views was used to improve segmentation accuracy. Prospective evaluation was conducted by measuring the amount of manual editing required in 91 H&N CT scans acquired February-May 2021.Main results. Medians and inter-quartile ranges of Dice similarity coefficients (DSC) computed on the retrospective testing set (N = 24) were 0.87 (0.85-0.89) for the masseters, 0.80 (0.79-0.81) for the medial pterygoids, 0.81 (0.79-0.84) for the larynx, and 0.69 (0.67-0.71) for the constrictor. Auto-segmentations, when compared to two sets of manual segmentations in 10 randomly selected scans, showed better agreement (DSC) with each observer than inter-observer DSC. Prospective analysis showed most manual modifications needed for clinical use were minor, suggesting auto-contouring could increase clinical efficiency. Trained segmentation models are available for research use upon request viahttps://github.com/cerr/CERR/wiki/Auto-Segmentation-models.Significance.We developed deep learning-based auto-segmentation models for swallowing and chewing structures in CT and demonstrated its potential for use in treatment planning to limit complications post-RT. To the best of our knowledge, this is the only prospectively-validated deep learning-based model for segmenting chewing and swallowing structures in CT. Segmentation models have been made open-source to facilitate reproducibility and multi-institutional research.

Can the Risk of Dysphagia in Head and Neck Radiation Therapy Be Predicted by an Automated Transit Fluence Monitoring Process During Treatment? A First Comparative Study of Patient Reported Quality of Life and the Fluence-Based Decision Support Metric

PURPOSE/OBJECTIVE(S)

The additional personnel and imaging procedures required for Adaptive Radiation Therapy (ART) pose a challenge for a broad implementation. We hypothesize that a change in transit fluence during the treatment course is correlated with the change of quality of life and thus can be used as a replanning trigger.

MATERIALS/METHODS

Twenty-one head and neck cancer (HNC) patients filled out an MD Anderson Dysphagia Inventory (MDADI) questionnaire, before-and-after the radiotherapy treatment course. The transit fluence was measured by the Watchdog (WD) in-vivo portal dosimetry system. The patients were monitored with daily WD and weekly CBCTs. The region of interest (ROI) of each patient was defined as the outer contour of the patient between approximate spine levels C1 to C4, essentially the neck and mandible inside the beam's eye view. The nth day integrated transit fluence change, Δϕ_n, and the volume change, ΔV_ROI, of the ROI of each patient was calculated from the corresponding WD and CBCT measurements. The correlation between MDADI scores and age, gender, planning mean dose to salivary glands <D_sg>, weight change ΔW, ΔV_ROI, and Δϕ_n, were analyzed using the ranked-Pearson correlation.

RESULTS

No statistically significant correlation was found for age, gender and ΔW. <D_sg> was found to have clinically important correlation with functional MDADI (ρ = -0.39, P = 0.081). ΔV_ROI was found to have statistically significant correlation of 0.44, 0.47 and 0.44 with global, physical and functional MDADI (P-value < 0.05). Δϕ_n was found to have statistically significant ranked-correlation (-0.46, -0.46 and -0.45) with physical, functional and total MDADI (P-value < 0.05).

CONCLUSION

A transit fluence based decision support metric (DSM) is statistically correlated with the dysphagia risk. It can not only be used as an early signal in assisting clinicians in the ART patient selection for replanning, but also lowers the resource barrier of ART implementation.

Clinical and Dosimetric Predictors of Radiation Pneumonitis in Patients With Non-Small Cell Lung Cancer Undergoing Postoperative Radiation Therapy

PURPOSE

Radiation pneumonitis (RP) is a common and potentially life-threatening toxicity from lung cancer radiation therapy. Data sets reporting RP rates after postoperative radiation therapy (PORT) have historically been small and with predominantly outdated field designs and radiation techniques. We examined a large cohort of patients in this context to assess the incidence and causes of RP in the modern era.

METHODS AND MATERIALS

We reviewed 285 patients with non-small cell lung cancer treated with PORT at our institution from May 2004 to January 2017. Complete dosimetric data and clinical records were reviewed and analyzed with grade 2 or higher RP as the endpoint (RP2+) (Common Terminology Criteria for Adverse Events v4.0). Patients were a median of 67 years old (range, 28-87), and most had pathologic stage III non-small cell lung cancer (91%) and received trimodality therapy (90%). Systematic dosimetric analyses using Dx increments of 5% and Vx increments of 2 Gy were performed to robustly evaluate dosimetric variables. Lung V₅ was also evaluated.

RESULTS

The incidence of RP2+ after PORT was 12.6%. Dosimetric factors most associated with RP2+ were total lungV₄ (hazard ratio [HR] 1.04, P < .001) and heart V₁₆ (HR 1.03, P = .001). On univariate analysis, the clinical factors of age (HR 1.05, P = .006) and carboplatin chemotherapy (HR 2.32, P = .012) were correlated with RP2+. On step-up multivariate analysis, only bivariate models remained significant, including lungV₅ (HR 1.037, P < .001) and age (HR 1.052, P = .011).

CONCLUSIONS

The incidence of RP after PORT is consistent with the literature. Factors correlated with RP include lung and heart doses, age, and carboplatin chemotherapy. These data also suggest that elderly patients may be more susceptible to lower doses of radiation to the lung. Based on these data, dose constraints to limit the risk of RP2+ to <5% in the setting of PORT include lungV₅ ≤65% in patients <65 years old and lungV₅ ≤36% in patients 65 years or older.

Quality of Life Implications After Transoral Robotic Surgery for Oropharyngeal Cancers

Oropharyngeal cancers and their treatment can exquisitely affect a patient's quality of life and functional outcome. Transoral robotic surgery offers a minimally invasive surgical approach that mitigates injury from traditional open surgical approaches and offers a treatment more likely to have short-term side effects compared with nonsurgical treatment. Feeding tube dependence, oral intake, and swallowing questionnaires, in addition to swallowing evaluations provide a snapshot of a patient's current swallowing function. Investigation of patient-reported quality-of-life outcomes allows for understanding of their symptomatology and the comparison of different treatment strategies.

Radiotherapy dose-volume parameters predict videofluoroscopy-detected dysphagia per DIGEST after IMRT for oropharyngeal cancer: Results of a prospective registry

PURPOSE

Our primary aim was to prospectively validate retrospective dose-response models of chronic radiation-associated dysphagia (RAD) after intensity modulated radiotherapy (IMRT) for oropharyngeal cancer (OPC). The secondary aim was to validate a grade ≥2 cut-point of the published videofluoroscopic dysphagia severity (Dynamic Imaging Grade for Swallowing Toxicity, DIGEST) as radiation dose-dependent.

MATERIAL AND METHODS

Ninety-seven patients enrolled on an IRB-approved prospective registry protocol with stage I-IV OPC underwent pre- and 3-6 month post-RT videofluoroscopy. Dose-volume histograms (DVH) for swallowing regions of interest (ROI) were calculated. Dysphagia severity was graded per DIGEST criteria (dichotomized with grade ≥2 as moderate/severe RAD). Recursive partitioning analysis (RPA) and Bayesian Information Criteria (BIC) were used to identify dose-volume effects associated with moderate/severe RAD.

RESULTS

31% developed moderate/severe RAD (i.e. DIGEST grade ≥2) at 3-6 months after RT. RPA found DVH-derived dosimetric parameters of geniohyoid/mylohyoid (GHM), superior pharyngeal constrictor (SPC), and supraglottic region were associated with DIGEST grade ≥2 RAD. V61 ≥ 18.57% of GHM demonstrated optimal model performance for prediction of DIGEST grade ≥2.

CONCLUSION

The findings from this prospective longitudinal registry validate prior observations that dose to submental musculature predicts for increased burden of dysphagia after oropharyngeal IMRT. Findings also support dichotomization of DIGEST grade ≥2 as a dose-dependent split for use as an endpoint in trials or predictive dose-response analysis of videofluoroscopy results.