MR-guided stereotactic radiation therapy for head and neck cancers

Purpose

MR-guided radiotherapy (MRgRT) has the advantage of utilizing high soft tissue contrast imaging to track daily changes in target and critical organs throughout the entire radiation treatment course. Head and neck (HN) stereotactic body radiation therapy (SBRT) has been increasingly used to treat localized lesions within a shorter timeframe. The purpose of this study is to examine the dosimetric difference between the step-and-shot intensity modulated radiation therapy (IMRT) plans on Elekta Unity and our clinical volumetric modulated arc therapy (VMAT) plans on Varian TrueBeam for HN SBRT.

Method

Fourteen patients treated on TrueBeam sTx with VMAT treatment plans were re-planned in the Monaco treatment planning system for Elekta Unity MR-Linac (MRL). The plan qualities, including target coverage, conformity, homogeneity, nearby critical organ doses, gradient index and low dose bath volume, were compared between VMAT and Monaco IMRT plans. Additionally, we evaluated the Unity adaptive plans of adapt-to-position (ATP) and adapt-to-shape (ATS) workflows using simulated setup errors for five patients and assessed the outcomes of our treated patients.

Results

Monaco IMRT plans achieved comparable results to VMAT plans in terms of target coverage, uniformity and homogeneity, with slightly higher target maximum and mean doses. The critical organ doses in Monaco IMRT plans all met clinical goals; however, the mean doses and low dose bath volumes were higher than in VMAT plans. The adaptive plans demonstrated that the ATP workflow may result in degraded target coverage and OAR doses for HN SBRT, while the ATS workflow can maintain the plan quality.

Conclusion

The use of Monaco treatment planning and online adaptation can achieve dosimetric results comparable to VMAT plans, with the additional benefits of real-time tracking of target volume and nearby critical structures. This offers the potential to treat aggressive and variable tumors in HN SBRT and improve local control and treatment toxicity.

Development and Standardization of an Osteoradionecrosis Classification System in Head and Neck Cancer: Implementation of a Risk-Based Model

PURPOSE

Osteoradionecrosis of the jaw (ORN) can manifest in varying severity. The aim of this study is to identify ORN risk factors and develop a novel classification to depict the severity of ORN.

METHODS

Consecutive patients with head and neck cancer (HNC) treated with curative-intent intensity-modulated radiation therapy (IMRT) (≥45 Gy) from 2011 to 2017 were included. Occurrence of ORN was identified from in-house prospective dental and clinical databases and charts. Multivariable logistic regression model was used to identify risk factors and stratify patients into high-risk and low-risk groups. A novel ORN classification system was developed to depict ORN severity by modifying existing systems and incorporating expert opinion. The performance of the novel system was compared with 15 existing systems for their ability to identify and predict serious ORN event (jaw fracture or requiring jaw resection).

RESULTS

ORN was identified in 219 of 2,732 (8%) consecutive patients with HNC. Factors associated with high risk of ORN were oral cavity or oropharyngeal primaries, received IMRT dose ≥60 Gy, current/ex-smokers, and/or stage III to IV periodontal condition. The ORN rate for high-risk versus low-risk patients was 12.7% versus 3.1% (P < .001) with an AUC of 0.71. Existing ORN systems overclassified serious ORN events and failed to recognize maxillary ORN. A novel ORN classification system, ClinRad, was proposed on the basis of vertical extent of bone necrosis and presence/absence of exposed bone/fistula. This system detected serious ORN events in 5.7% of patients and statistically outperformed existing systems.

CONCLUSION

We identified risk factors for ORN and proposed a novel ORN classification system on the basis of vertical extent of bone necrosis and presence/absence of exposed bone/fistula. It outperformed existing systems in depicting the seriousness of ORN and may facilitate clinical care and clinical trials.

Optimizing Outpatient Radiation Oncology Consult Workflow by Using Time-Driven Activity-Based Costing: Efficiency and Financial Impacts

PURPOSE

Clinical efficiency is a key component of value-based health care. Our objective here was to identify workflow inefficiencies by using time-driven activity-based costing (TDABC) and evaluate the implementation of a new clinical workflow in high-volume outpatient radiation oncology clinics.

METHODS

Our quality improvement study was conducted with the Departments of GI, Genitourinary (GU), and Thoracic Radiation Oncology at a large academic cancer center and four community network sites. TDABC was used to create process maps and optimize workflow for outpatient consults. Patient encounter metrics were captured with a real-time status function in the electronic medical record. Time metrics were compared using Mann-Whitney U tests.

RESULTS

Individual patient encounter data for 1,328 consults before the intervention and 1,234 afterward across all sections were included. The median overall cycle time was reduced by 21% in GI (19 minutes), 18% in GU (16 minutes), and 12% at the community sites (9 minutes). The median financial savings per consult were $52 in US dollars (USD) for the GI, $33 USD for GU, $30 USD for thoracic, and $42 USD for the community sites. Patient satisfaction surveys (from 127 of 228 patients) showed that 99% of patients reported that their providers spent adequate time with them and 91% reported being seen by a care provider in a timely manner.

CONCLUSION

TDABC can effectively identify opportunities to improve clinical efficiency. Implementing workflow changes on the basis of our findings led to substantial reductions in overall encounter cycle times across several departments, as well as high patient satisfaction and significant financial savings.

Clinical and prognostic differences in oropharyngeal squamous cell carcinoma in USA and Denmark, two HPV high-prevalence areas

BACKGROUND

Uncertainty persists regarding clinical and treatment variations crucial to consider when comparing high human papillomavirus (HPV)-prevalence oropharyngeal squamous cell carcinoma (OPSCC) cohorts for accurate patient stratification and replicability of clinical trials across different geographical areas.

METHODS

OPSCC patients were included from The University of Texas MD Anderson Cancer Center (UTMDACC), USA and from The University Hospital of Copenhagen, Denmark from 2015-2020, (n = 2484). Outcomes were 3-year overall survival (OS) and recurrence-free interval (RFI). Subgroup analyses were made for low-risk OPSCC patients (T1-2N0M0) and high-risk patients (UICC8 III-IV).

RESULTS

There were significantly more HPV-positive (88.2 % vs. 63.1 %), males (89.4 % vs. 74.1 %), never-smokers (52.1 % vs. 23.7 %), lower UICC8-stage (I/II: 79.3 % vs. 68 %), and fewer patients treated with radiotherapy (RT) alone (14.8 % vs. 30.3 %) in the UTMDACC cohort. No difference in the adjusted OS was observed (hazard ratio [HR] 1.21, p = 0.23), but a significantly increased RFI HR was observed for the Copenhagen cohort (HR: 1.74, p = 0.003). Subgroup analyses of low- and high-risk patients revealed significant clinical and treatment differences. No difference in prognosis was observed for low-risk patients, but the prognosis for high-risk patients in the Copenhagen cohort was worse (OS HR 2.20, p = 0.004, RFI HR 2.80, p = 0.002).

CONCLUSIONS

We identified significant differences in clinical characteristics, treatment modalities, and prognosis between a Northern European and Northern American OPSCC population. These differences are important to consider when comparing outcomes and for patient stratification in clinical trials, as reproducibility might be challenging.

Revisiting Feeding Tube Utilization in Oropharynx Cancer: 6-Year Prospective Registry Analysis

OBJECTIVE

Patients treated for oropharyngeal cancer (OPC) have historically demonstrated high feeding tube rates for decreased oral intake and malnutrition. We re-examined feeding tube practices in these patients.

STUDY DESIGN

Retrospective analysis of prospective cohort from 2015 to 2021.

SETTING

Single-institution NCI-Designated Comprehensive Cancer Center.

METHODS

With IRB approval, patients with new oropharyngeal squamous cell cancer or (unknown primary with neck metastasis) were enrolled. Baseline swallowing was assessed via videofluoroscopy and Performance Status Scale for Head and Neck Cancer (PSSHN). G-tubes or nasogastric tubes (NGT) were placed for weight loss before, during, or after treatment. Prophylactic NGT were placed during transoral robotic surgery (TORS). Tube duration was censored at last disease-free follow-up. Multivariate regression was performed for G-tube placement (odds ratio [OR] [95% confidence interval [CI]) and removal (Cox hazard ratio, hazard ratio [HR] [95% CI]).

RESULTS

Of 924 patients, most had stage I to II (81%), p16+ (89%), node-positive (88%) disease. Median follow-up was 2.6 years (interquartile range 1.5-3.9). Most (91%) received radiation/chemoradiation, and 16% received TORS. G-tube rate was 27% (5% after TORS). G-tube risk was increased with chemoradiation (OR 2.78 [1.87-4.22]) and decreased with TORS (OR 0.31 [0.15-0.57]) and PSSHN-Diet score ≥60 (OR 0.26 [0.15-0.45]). G-tube removal probability over time was lower for T3 to T4 tumors (HR 0.52 [0.38-0.71]) and higher for PSSHN-Diet score ≥60 (HR 1.65 [1.03-2.66]).

CONCLUSIONS

In this modern cohort of patients treated for OPC, 27% received G-tubes-50% less than institutional rates 10 years ago. Patients with preserved baseline swallowing and/or those eligible for TORS may have lower G-tube risk and duration.

International Expert-Based Consensus Definition, Staging Criteria, and Minimum Data Elements for Osteoradionecrosis of the Jaw: An Inter-Disciplinary Modified Delphi Study

Purpose

Osteoradionecrosis of the jaw (ORNJ) is a severe iatrogenic disease characterized by bone death after radiation therapy (RT) to the head and neck. With over 9 published definitions and at least 16 diagnostic/staging systems, the true incidence and severity of ORNJ are obscured by lack of a standard for disease definition and severity assessment, leading to inaccurate estimation of incidence, reporting ambiguity, and likely under-diagnosis worldwide. This study aimed to achieve consensus on an explicit definition and phenotype of ORNJ and related precursor states through data standardization to facilitate effective diagnosis, monitoring, and multidisciplinary management of ORNJ.

Methods

The ORAL Consortium comprised 69 international experts, including representatives from medical, surgical, radiation oncology, and oral/dental disciplines. Using a web-based modified Delphi technique, panelists classified descriptive cases using existing staging systems, reviewed systems for feature extraction and specification, and iteratively classified cases based on clinical/imaging feature combinations.

Results

The Consortium ORNJ definition was developed in alignment with SNOMED-CT terminology and recent ISOO-MASCC-ASCO guideline recommendations. Case review using existing ORNJ staging systems showed high rates of inability to classify (up to 76%). Ten consensus statements and nine minimum data elements (MDEs) were outlined for prospective collection and classification of precursor/ORNJ stages.

Conclusion

This study provides an international, consensus-based definition and MDE foundation for standardized ORNJ reporting in cancer survivors treated with RT. Head and neck surgeons, radiation, surgical, medical oncologists, and dental specialists should adopt MDEs to enable scalable health information exchange and analytics. Work is underway to develop both a human- and machine-readable knowledge representation for ORNJ (i.e., ontology) and multidisciplinary resources for dissemination to improve ORNJ reporting in academic and community practice settings.

Comparison of Machine Leaning Models for Prediction of Acute Pain Severity and On-Treatment Opioid Utilization in Oral Cavity and Oropharyngeal Cancer Patients Receiving Radiation Therapy: Exploratory Analysis from a Large-Scale Retrospective Cohort

Background

Acute pain is a common and debilitating symptom experienced by oral cavity and oropharyngeal cancer (OC/OPC) patients undergoing radiation therapy (RT). Uncontrolled pain can result in opioid overuse and increased risks of long-term opioid dependence. The specific aim of this exploratory analysis was the prediction of severe acute pain and opioid use in the acute on-treatment setting, to develop risk-stratification models for pragmatic clinical trials.

Materials and Methods

A retrospective study was conducted on 900 OC/OPC patients treated with RT during 2017 to 2023. Clinical data including demographics, tumor data, pain scores and medication data were extracted from patient records. On-treatment pain intensity scores were assessed using a numeric rating scale (0-none, 10-worst) and total opioid doses were calculated using morphine equivalent daily dose (MEDD) conversion factors. Analgesics efficacy was assessed based on the combined pain intensity and the total required MEDD. ML models, including Logistic Regression (LR), Support Vector Machine (SVM), Random Forest (RF), and Gradient Boosting Model (GBM) were developed and validated using ten-fold cross-validation. Performance of models were evaluated using discrimination and calibration metrics. Feature importance was investigated using bootstrap and permutation techniques.

Results

For predicting acute pain intensity, the GBM demonstrated superior area under the receiver operating curve (AUC) (0.71), recall (0.39), and F1 score (0.48). For predicting the total MEDD, LR outperformed other models in the AUC (0.67). For predicting the analgesics efficacy, SVM achieved the highest specificity (0.97), and best calibration (ECE of 0.06), while RF and GBM achieved the same highest AUC, 0.68. RF model emerged as the best calibrated model with ECE of 0.02 for pain intensity prediction and 0.05 for MEDD prediction. Baseline pain scores and vital signs demonstrated the most contributed features for the different predictive models.

Conclusion

These ML models are promising in predicting end-of-treatment acute pain and opioid requirements and analgesics efficacy in OC/OPC patients undergoing RT. Baseline pain score, vital sign changes were identified as crucial predictors. Implementation of these models in clinical practice could facilitate early risk stratification and personalized pain management. Prospective multicentric studies and external validation are essential for further refinement and generalizability.

Artificial Intelligence and Machine Learning in Cancer Related Pain: A Systematic Review

Background/objective

Pain is a challenging multifaceted symptom reported by most cancer patients, resulting in a substantial burden on both patients and healthcare systems. This systematic review aims to explore applications of artificial intelligence/machine learning (AI/ML) in predicting pain-related outcomes and supporting decision-making processes in pain management in cancer.

Methods

A comprehensive search of Ovid MEDLINE, EMBASE and Web of Science databases was conducted using terms including "Cancer", "Pain", "Pain Management", "Analgesics", "Opioids", "Artificial Intelligence", "Machine Learning", "Deep Learning", and "Neural Networks" published up to September 7, 2023. The screening process was performed using the Covidence screening tool. Only original studies conducted in human cohorts were included. AI/ML models, their validation and performance and adherence to TRIPOD guidelines were summarized from the final included studies.

Results

This systematic review included 44 studies from 2006-2023. Most studies were prospective and uni-institutional. There was an increase in the trend of AI/ML studies in cancer pain in the last 4 years. Nineteen studies used AI/ML for classifying cancer patients' pain development after cancer therapy, with median AUC 0.80 (range 0.76-0.94). Eighteen studies focused on cancer pain research with median AUC 0.86 (range 0.50-0.99), and 7 focused on applying AI/ML for cancer pain management decisions with median AUC 0.71 (range 0.47-0.89). Multiple ML models were investigated with. median AUC across all models in all studies (0.77). Random forest models demonstrated the highest performance (median AUC 0.81), lasso models had the highest median sensitivity (1), while Support Vector Machine had the highest median specificity (0.74). Overall adherence of included studies to TRIPOD guidelines was 70.7%. Lack of external validation (14%) and clinical application (23%) of most included studies was detected. Reporting of model calibration was also missing in the majority of studies (5%).

Conclusion

Implementation of various novel AI/ML tools promises significant advances in the classification, risk stratification, and management decisions for cancer pain. These advanced tools will integrate big health-related data for personalized pain management in cancer patients. Further research focusing on model calibration and rigorous external clinical validation in real healthcare settings is imperative for ensuring its practical and reliable application in clinical practice.

Systematic Review of Genetic Polymorphisms Associated with Acute Pain Induced by Radiotherapy for Head and Neck Cancers

Background/objective

Pain is the most common acute symptom following radiation therapy (RT) for head and neck cancer (HNC). The multifactorial origin of RT-induced pain makes it highly challenging to manage. Multiple studies were conducted to identify genetic variants associated with cancer pain, however few of them focused on RT-induced acute pain. In this review, we summarize the potential mechanisms of acute pain after RT in HNC and identify genetic variants associated with RT-induced acute pain and relevant acute toxicities.

Methods

A comprehensive search of Ovid Medline, EMBASE and Web of Science databases using terms including "Variants", "Polymorphisms", "Radiotherapy", "Acute pain", "Acute toxicity" published up to February 28, 2022, was performed by two reviewers. Review articles and citations were reviewed manually. The identified SNPs associated with RT-induced acute pain and toxicities were reported, and the molecular functions of the associated genes were described based on genetic annotation using The Human Gene Database; GeneCards.

Results

A total of 386 articles were identified electronically and 8 more articles were included after manual search. 21 articles were finally included. 32 variants in 27 genes, of which 25% in inflammatory/immune response, 20% had function in DNA damage response and repair, 20% in cell death or cell cycle, were associated with RT-inflammatory pain and acute oral mucositis or dermatitis. 4 variants in 4 genes were associated with neuropathy and neuropathic pain. 5 variants in 4 genes were associated with RT-induced mixed types of post-RT-throat/neck pain.

Conclusion

Different types of pain develop after RT in HNC, including inflammatory pain; neuropathic pain; nociceptive pain; and mixed oral pain. Genetic variants involved in DNA damage response and repair, cell death, inflammation and neuropathic pathways may affect pain presentation post-RT. These variants could be used for personalized pain management in HNC patients receiving RT.

Clinical Acceptability of Automatically Generated Elective Lymph Node Volumes for Head and Neck Cancer Patients

PURPOSE/OBJECTIVE(S)

Manual contouring of head and neck lymph node levels is a time-intensive process prone to provider-specific variation. The purpose of this work is to generate a clinical segmentation tool while minimizing the amount of manual effort required by physicians to develop training datasets and review contours. Here we investigate an approach to curate, develop, and clinically validate an auto-contouring model for standard cervical lymph node volumes in the head and neck using a publicly available deep learning architecture. This model updates our previously validated tool to reflect modern practices in lymph node segmentation.

MATERIALS/METHODS

With the assistance of a resident physician, five radiation oncologists manually contoured individual lymph node levels on CT scans for three separate patients treated definitively with radiation or chemoradiation for oropharynx cancer, resulting in 15 unique ground truth cases. These cases were then used to train an nnUnet deep-learning model to generate automated contours for 32 additional cases. These 32 cases were reviewed, manually edited, and used to create the final model. Finally, the model was used to generate contours on the original 15 CT scans (testing cohort), and providers compared these automated contours with the ground-truth (manual) contours. Two blinded studies were performed. In a double-blinded fashion, providers were first asked to select which set of contours they would prefer to use in clinical practice as a starting point for actual cases. Second, they scored each contour on a Likert scale (1-5) to indicate clinical acceptability, ranging from completely unusable to usable without modification.

RESULTS

Across all lymph node levels (IA, IB, II, III, IV, V, RP), average Dice Similarity Coefficient ranged from 0.77 to 0.89 for AI vs manual contours in the testing cohort. These AI and manual lymph node contours were reviewed by 5 physicians each, resulting in 525 preference scores. Across all lymph nodes, the AI contour was superior to or equally preferred to the manual contours at rates ranging from 75% to 91% in the first blinded study. In the second blinded study, physician preference for the manual vs AI contour was statistically different for only the RP contours (p < 0.01). Thus, there was not a significant difference in clinical acceptability for nodal levels I-V for manual versus AI contours. Across all physician-generated contours, 82% were rated as usable with stylistic to no edits, and across all AI-generated contours, 92% were rated as usable with stylistic to no edits.

CONCLUSION

An approach to generate clinically acceptable automated contours for cervical lymph node levels in the head and neck was demonstrated. Furthermore, for nodal levels I-V, there was no significant difference in clinical acceptability in manual vs AI contours. Because we were able to generate and validate a model for each lymph node level individually, the output is applicable to a complete range of disease in which cervical lymph nodes are treated.

Dose Constraints and Planning Considerations for Thoracic Radiation Therapy: Delphi Consensus from a National Survey of Experts

PURPOSE/OBJECTIVE(S)

Many physicians refer to trial protocols or published guidelines (NCCN, QUANTEC, HyTEC) for dose-volume histogram (DVH) metrics. However, there may be variation in implementing these metrics during plan optimization. Some studies have suggested better outcomes for patients treated at high-volume, high-expertise centers. These differences may in part be due to greater standardization or center-specific treatment planning processes. We surveyed radiation oncologists with stated thoracic-specific expertise using the Delphi method to formulate consensus DVH metrics that would be considered ideal for high-quality radiation treatment plans.

MATERIALS/METHODS

Thoracic radiation oncology experts were identified using departmental websites of ACGME-accredited radiation oncology programs. After confirming their expertise, panelists were invited to submit their institutional templates and complete three rounds of questions related to normal organ dose constraints, target coverage metrics, prescribing practices, and other planning considerations. Queried radiation schemes included conventional fractionation, twice-daily fractionation, and stereotactic body radiation therapy (3 and 5 fractions). Preliminary consensus statements were generated using median values for DVH metrics and were iteratively refined in subsequent surveys. Consensus was pre-defined as ≥75% agreement among panelists.

RESULTS

A total of 194 experts were invited, and 100 agreed to participate. The panel was 28% female and included experts from 29 states with a median of 11 years of clinical experience (IQR 6-19). 89% specialized in 1-2 disease sites. Response rates for the Demographics, round 1, 2, and 3 surveys were 83%, 78%, 57%, and 55%, respectively. 93% of panelists believed that DVH metrics should provide thresholds for both optimal and acceptable criteria for treatment planning. 49 of the 96 proposed normal tissue dose constraint statements were iterated to consensus (Table 1), and 5 of 7 proposed target coverage metric statements achieved consensus.

CONCLUSION

This study highlights the heterogeneity in metrics used by thoracic radiation oncologists and provides levels of consensus on ideal and acceptable dose constraints as guidance for treatment planning. Future directions include using these statements to develop prescription templates and acceptance criteria for treatment planning systems for widespread use as well as extending this Delphi approach to additional disease sites.

Fractionated Stereotactic Radiotherapy in the Management of Dural Recurrence of Olfactory Neuroblastoma

PURPOSE/OBJECTIVE(S)

Treatment protocols for dural recurrence among esthesioneuroblastoma patients have not been standardized. We assess the outcomes of fractionated stereotactic radiotherapy (FSR) for patients with olfactory neuroblastoma (ONB) dura-based recurrences.

MATERIALS/METHODS

We identified ONB patients with dura-based recurrences treated with FSR after prior radiotherapy who were enrolled between 2013 and 2022 in our prospective head and neck reirradiation and skull base registries. In-field tumor control (within 2 cm of prescribed radiotherapy volume) and out-of-field tumor control (non-contiguous or contralateral dura, nodal, or distant metastases) were analyzed.

RESULTS

Thirteen patients with 28 dural lesions were included in this analysis. All patients were initially treated with surgery to their primary paranasal sinus disease; 69% with a craniofacial approach followed by adjuvant radiotherapy to a median dose of 63 Gy (range 60-72.4 Gy) prescribed to the resected tumor bed. Patients re-presented with dural recurrence at median 58.3 months (range 35.0 - 163.0 months) from completion of their initial treatment. Two patients underwent dural resections. On presentation of recurrence, 4 patients had 1 lesion treated, with a median of 2 lesions treated (range 1-4 lesions). All dural based tumors were treated with FSR to a median dose of 27 Gy in 3 fractions delivered QOD. 68Ga-DOTATATE PET/CT was utilized for FSR treatment planning in 31% of cases. The median follow up from FSR was 23.3 months (range: 13.1 - 51.6 months). The 1-year overall survival and progression free survival was 75% and 38%, respectively. The 1- and 2-year in-field control rate was 85% and 75%, respectively. Among treated lesions, 25 of 28 (89%) responded or remained stable following FSR. Two patients (3 lesions) had evidence of in-field radiographic progression at 17 and 9 months, respectively. Five patients (38%) experienced progression in the contralateral or non-contiguous dura, and 5 patients (38%) developed distant metastases. The overall out-of-field progression rate was 58% at 1 year. There was no grade 3 or higher toxicity observed. Three patients (23%) developed asymptomatic changes on MRI consistent with brain necrosis, all of which occurred in a previously irradiated region.

CONCLUSION

In the largest single institution study of FSR reirradiation for ONB dural recurrence to date, high local control rates with minimal toxicity are attainable. However, subsequent out-of-field dural recurrences and/or distant metastases remain problematic.

Development and Standardization of a Classification System for Osteoradionecrosis: Implementation of a Risk-Based Model

Purpose

Osteoradionecrosis of the jaw (ORN) can manifest in varying severity. The aim of this study is to identify ORN risk factors and develop a novel classification to depict the severity of ORN.

Methods

Consecutive head-and-neck cancer (HNC) patients treated with curative-intent IMRT (≥ 45Gy) in 2011-2018 were included. Occurrence of ORN was identified from in-house prospective dental and clinical databases and charts. Multivariable logistic regression model was used to identify risk factors and stratify patients into high-risk and low-risk groups. A novel ORN classification system was developed to depict ORN severity by modifying existing systems and incorporating expert opinion. The performance of the novel system was compared to fifteen existing systems for their ability to identify and predict serious ORN event (jaw fracture or requiring jaw resection).

Results

ORN was identified in 219 out of 2732 (8%) consecutive HNC patients. Factors associated with high-risk of ORN were: oral-cavity or oropharyngeal primaries, received IMRT dose ≥60Gy, current/ex-smokers, and/or stage III-IV periodontal disease. The ORN rate for high-risk vs low-risk patients was 12.7% vs 3.1% (p<0.001) with an area-under-the-receiver-operating-curve (AUC) of 0.71. Existing ORN systems overclassified serious ORN events and failed to recognize maxillary ORN. A novel ORN classification system, RadORN, was proposed based on vertical extent of bone necrosis and presence/absence of exposed bone/fistula. This system detected serious ORN events in 5.7% of patients and statistically outperformed existing systems.

Conclusion

We identified risk factors for ORN, and proposed a novel ORN classification system based on vertical extent of bone necrosis and presence/absence of exposed bone/fistula. It outperformed existing systems in depicting the seriousness of ORN, and may facilitate clinical care and clinical trials.

Temporal characterization of acute pain and toxicity kinetics during radiation therapy for head and neck cancer. A retrospective study

Objectives

Pain during Radiation Therapy (RT) for oral cavity/oropharyngeal cancer (OC/OPC) is a clinical challenge due to its multifactorial etiology and variable management. The objective of this study was to define complex pain profiles through temporal characterization of pain descriptors, physiologic state, and RT-induced toxicities for pain trajectories understanding.

Materials and methods

Using an electronic health record registry, 351 OC/OPC patients treated with RT from 2013 to 2021 were included. Weekly numeric scale pain scores, pain descriptors, vital signs, physician-reported toxicities, and analgesics were analyzed using linear mixed effect models and Spearman's correlation. Area under the pain curve (AUCpain) was calculated to measure pain burden over time.

Results

Median pain scores increased from 0 during the weekly visit (WSV)-1 to 5 during WSV-7. By WSV-7, 60% and 74% of patients reported mouth and throat pain, respectively, with a median pain score of 5. Soreness and burning pain peaked during WSV-6/7 (51%). Median AUCpain was 16% (IQR (9.3-23)), and AUCpain significantly varied based on gender, tumor site, surgery, drug use history, and pre-RT pain. A temporal increase in mucositis and dermatitis, declining mean bodyweight (-7.1%; P < 0.001) and mean arterial pressure (MAP) 6.8 mmHg; P < 0.001 were detected. Pulse rate was positively associated while weight and MAP were negatively associated with pain over time (P < 0.001).

Conclusion

This study provides insight on in-depth characterization and associations between dynamic pain, physiologic, and toxicity kinetics. Our findings support further needs of optimized pain control through temporal data-driven clinical decision support systems for acute pain management.

Hypothyroidism following Radiotherapy for Head and Neck Cancer: A Systematic Review of the Literature and Opportunities to Improve the Therapeutic Ratio

(1) Background: Radiotherapy (RT) is a central component for the treatment of many head and neck cancers. In this systematic review of the literature, we aimed to characterize and quantify the published evidence on RT-related hypothyroidism, including estimated incidence, clinical risk factors, and dosimetric parameters that may be used to guide clinical decision making. Furthermore, we aimed to identify potential areas of improvement in the prevention and clinical management of RT-induced hypothyroidism, including the role of modern advanced therapeutic techniques. (2) Methods: We conducted a systemic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed and Google Scholar were searched to identify original research articles describing the incidence, mechanism, dosimetry, treatment, or prevention of radiation-related hypothyroidism for adults receiving RT for the treatment of head and neck cancers. The snowball method was used to identify additional articles. For identified articles, we tabulated several datapoints, including publication date, patient sample size, estimated hypothyroidism incidence, cancer site/type, follow-up period, radiation modality and technique, use of multimodality therapy, method of thyroid function evaluation, and proposed dosimetric predictors of hypothyroidism. (3) Results: One hundred and eleven articles met inclusion criteria, reflecting a range of head and neck cancer subtypes. There was a large variation in the estimated incidence of RT-related hypothyroidism, with a median estimate of 36% (range 3% to 79%). Reported incidence increased in later publication dates, which was likely related to improved screening and longer follow up. There were a wide variety of predictive metrics used to identify patients at high risk of hypothyroidism, the most common of which were volumetric and mean dosimetrics related to the thyroid gland (Vxx%, Dmean). More recently, there has been increasing evidence to suggest that the thyroid gland volume itself and the volume of the thyroid gland spared from high-dose radiation (VSxx) may better predict thyroid function after RT. There were no identified studies investigating the role of advanced radiotherapeutic techniques such as MRI-guided RT or particle therapy to decrease RT-related hypothyroidism. Conclusions: Hypothyroidism is a common toxicity resulting from therapeutic radiation for head and neck cancer with recent estimates suggesting 40-50% of patients may experience hypothyroidism after treatment. Dosimetric predictive models are increasingly able to accurately identify patients at risk of hypothyroidism, especially those utilizing thyroid VS metrics. Further investigation regarding the potential for advanced radiotherapeutic therapies to decrease RT-induced thyroid dysfunction is needed.

Optimized decision support for selection of transoral robotic surgery or (chemo)radiation therapy based on posttreatment swallowing toxicity

BACKGROUND

A primary goal in transoral robotic surgery (TORS) for oropharyngeal squamous cell cancer (OPSCC) survivors is to optimize swallowing function. However, the uncertainty in the outcomes of TORS including postoperative residual positive margin (PM) and extranodal extension (ENE), may necessitate adjuvant therapy, which may cause significant swallowing toxicity to survivors.

METHODS

A secondary analysis was performed on a prospective registry data with low- to intermediate-risk human papillomavirus-related OPSCC possibly resectable by TORS. Decision trees were developed to model the uncertainties in TORS compared with definitive radiation therapy (RT) and chemoradiation therapy (CRT). Swallowing toxicities were measured by Dynamic Imaging Grade of Swallowing Toxicity (DIGEST), MD Anderson Dysphagia Inventory (MDADI), and the MD Anderson Symptom Inventory-Head and Neck (MDASI-HN) instruments. The likelihoods of PM/ENE were varied to determine the thresholds within which each therapy remains optimal.

RESULTS

Compared with RT, TORS resulted in inferior swallowing function for moderate likelihoods of PM/ENE (>60% in short term for all instruments, >75% in long term for DIGEST and MDASI) leaving RT as the optimal treatment. Compared with CRT, TORS remained the optimal therapy based on MDADI and MDASI but showed inferior swallowing outcomes based on DIGEST for moderate-to-high likelihoods of PM/ENE (>75% for short-term and >40% for long-term outcomes).

CONCLUSION

In the absence of reliable estimation of postoperative PM/ENE concurrent with significant postoperative PM, the overall toxicity level in OPSCC patients undergoing TORS with adjuvant therapy may become more severe compared with patients receiving nonsurgical treatments thus advocating definitive (C)RT protocols.

Using patient flow analysis with real-time patient tracking to optimize radiation oncology consultation visits

PURPOSE

Clinical efficiency is a key component of the value-based care model and a driver of patient satisfaction. The purpose of this study was to identify and address inefficiencies at a high-volume radiation oncology clinic.

METHODS AND MATERIALS

Patient flow analysis (PFA) was used to create process maps and optimize the workflow of consultation visits in a gastrointestinal radiation oncology clinic at a large academic cancer center. Metrics such as cycle times, waiting times, and rooming times were assessed by using a real-time patient status function in the electronic medical record for 556 consults and compared between before vs after implementation of the PFA recommendations.

RESULTS

The initial PFA revealed four inefficiencies: (1) protracted rooming time, (2) inefficient communications, (3) duplicated tasks, and (4) ambiguous clinical roles. We analyzed 485 consult-visits before the PFA and 71 after the PFA. The PFA recommendations led to reductions in overall median cycle time by 21% (91 min vs 72 min, p < 0.001), in cumulative waiting times by 64% (45 min vs 16 min; p < 0.001), which included waiting room time (14 min vs 5 min; p < 0.001) and wait for physician (20 min vs. 6 min; p < 0.001). Slightly less than one-quarter (22%) of consult visits before the PFA lasted > 2 h vs. 0% after implementation of the recommendations (p < 0.001). Similarly, the proportion of visits requiring < 1 h was 16% before PFA vs 34% afterward (p < 0.001).

CONCLUSIONS

PFA can be used to identify clinical inefficiencies and optimize workflows in radiation oncology consultation clinics, and implementing their findings can significantly improve cycle times and waiting times. Potential downstream effects of these interventions include improved patient experience, decreased staff burnout, financial savings, and opportunities for expanding clinical capacity.

Adhering to Eat and Exercise Status During Radiotherapy for Oropharyngeal Cancer for Prevention and Mitigation of Radiotherapy-Associated Dysphagia

Importance

Previously published work reported independent benefit of maintenance of oral intake (eat) and swallowing exercise adherence (exercise) during radiotherapy (RT) on diet and functional outcomes. The current study seeks to validate the authors' previously published findings in a large contemporary cohort of patients with oropharynx cancer (OPC) and address limitations of the prior retrospective study using prospective, validated outcome measures.

Objective

To examine the longitudinal association of oral intake and swallowing exercise using validated, clinician-graded and patient-reported outcomes.

Design, Setting, and Participants

Secondary analysis of a prospective OPC registry including patients who underwent primary RT/chemoradiotherapy (CRT) or primary transoral robotic surgery plus RT/CRT for OPC at a single-institution comprehensive cancer center.

Exposures

Adherence to speech pathology swallowing intervention during RT coded as (1) eat: oral intake at end of RT (nothing by mouth [NPO]; partial oral intake [PO], with feeding tube [FT] supplement; full PO); and (2) exercise: swallowing exercise adherence (nonadherent vs partial/full adherence).

Main Outcomes and Measures

Feeding tube and diet (Performance Status Scale for Head and Neck Cancer) patient-reported swallowing-related quality of life (MD Anderson Dysphagia Inventory; MDADI) and clinician-graded dysphagia severity grade (videofluoroscopic Dynamic Imaging Grade of Swallowing Toxicity; DIGEST) were collected at baseline, 3 to 6 months, and 18 to 24 months post-RT.

Results

A total of 595 patients (mean [SD] age, 65 [10] years; 532 [89%] male) who underwent primary RT (111 of 595 [19%]), CRT (434 of 595 [73%]), or primary transoral robotic surgery plus RT/CRT (50 of 595 [8%]) were included in this cohort study. At the end of RT, 55 (9%) patients were NPO, 115 (19%) were partial PO, 425 (71%) were full PO, and 340 (57%) reported exercise adherence. After multivariate adjustment, subacute return to solid diet and FT were independently associated with oral intake (odds ratio [OR], 2.0; 95% CI, 1.0-4.1; OR, 0.1; 95% CI, 0.0-0.2, respectively) and exercise (OR, 2.9; 95% CI, 1.9-4.5; OR, 0.3; 95% CI, 0.1-0.5, respectively). Subacute MDADI (β = 6.5; 95% CI, 1.8-11.2), FT duration (days; β = -123.4; 95% CI, -148.5 to -98.4), and less severe dysphagia per DIGEST (OR, 0.6; 95% CI, 0.3-1.0) were independently associated with oral intake, while exercise was independently associated with less severe laryngeal penetration/aspiration per DIGEST-safety (OR, 0.7; 95% CI, 0.4-1.0). DIGEST grade associations with oral intake were not preserved long-term; however, exercise was associated with a higher likelihood of solid diet intake and better swallow safety per DIGEST.

Conclusions and Relevance

The findings of this cohort study extend the authors' previously published findings that oral intake and swallowing exercise during RT are associated with favorable functional outcomes, now demonstrated with broader domains of function using validated measures. Patterns of benefit differed in this study. Specifically, better subacute recovery of swallow-related quality of life and less severe dysphagia were found among patients who maintained oral intake independent of exercise adherence, and shorter FT utilization and better long-term diet and swallowing safety were found among those who exercised independent of oral intake.

Swallowing After Primary TORS and Unilateral or Bilateral Radiation for Low- to Intermediate-Risk Tonsil Cancer

OBJECTIVE

The primary course of treatment for patients with low- to intermediate-risk tonsil cancer has evolved with a shift toward primary transoral robotic surgery (TORS) or radiation therapy (RT). While favorable outcomes have been reported after deintensification via unilateral TORS or RT (uniRT), comparisons of functional outcomes between these treatments are lacking. We compared clinical outcomes (Dynamic Imaging Grade of Swallowing Toxicity [DIGEST] and feeding tube [FT]) and patient-reported swallowing outcomes (MD Anderson Dysphagia Inventory [MDADI]) based on primary treatment strategy: TORS, uniRT, or bilateral RT (biRT).

STUDY DESIGN

Secondary analysis of prospective cohort.

SETTING

Single institution.

METHODS

The study sample comprised 135 patients with HPV/p16+ T1-T3, N0-2b (American Joint Committee on Cancer, seventh edition), N0-1 (eighth edition) squamous cell carcinoma of the tonsil were sampled from a prospective registry. Modified barium swallow studies graded per DIGEST, FT placement and duration, and MDADI were collected.

RESULTS

Baseline DIGEST grade significantly differed among treatment groups, with higher dysphagia prevalence in the TORS group (34%) vs the biRT group (12%, P = .04). No significant group differences were found in DIGEST grade or dysphagia prevalence at subacute and longitudinal time points (P = .41). Mean MDADI scores were similar among groups at baseline (TORS, 92; uniRT, 93; biRT, 93; P = .90), subacute (TORS, 83; uniRT, 88; biRT, 82; P = .38) and late time points (TORS, 86; uniRT, 86; biRT, 87; P = .99). FT placement and duration significantly differed among primary treatment groups (FT [median days]: TORS, 89% [3]; uniRT, 8% [82]; biRT, 37% [104]; P < .001).

CONCLUSION

While TORS and uniRT offer optimal functional outcomes related to dysphagia, results suggest that no measurable clinician-graded or patient-reported differences in swallow outcomes exist among these primary treatment strategies and biRT. Aside from baseline differences that drive treatment selection, differences in FT rate and duration by primary treatment strategy likely reflect diverse toxicities beyond dysphagia.

Changes in Apparent Diffusion Coefficient (ADC) in Serial Weekly MRI during Radiotherapy in Patients with Head and Neck Cancer: Results from the PREDICT-HN Study

Background: The PREDICT-HN study aimed to systematically assess the kinetics of imaging MR biomarkers during head and neck radiotherapy. Methods: Patients with intact squamous cell carcinoma of the head and neck were enrolled. Pre-, during, and post-treatment MRI were obtained. Serial GTV and ADC measurements were recorded. The correlation between each feature and the GTV was calculated using Spearman’s correlation coefficient. The linear mixed model was used to evaluate the change in GTV over time. Results: A total of 41 patients completed the study. The majority (76%) had oropharyngeal cancer. A total of 36 patients had intact primary tumours that can be assessed on MRI, and 31 patients had nodal disease with 46 nodes assessed. Median primary GTV (GTVp) size was 14.1cc. The rate of GTVp shrinkage was highest between pre-treatment and week 4. Patients with T3-T4 tumours had a 3.8-fold decrease in GTVp compared to T1-T2 tumours. The ADC values correlated with residual GTVp. The median nodal volume (GTVn) was 12.4cc. No clinical features were found to correlate with GTVn reduction. The overall change in ADC for GTVn from pre-treatment was significant for 35th−95th percentiles in weeks 1−4 (p < 0.001). Conclusion: A discrepancy in the trajectory of ADC between primary and nodal sites suggested that they exhibit different treatment responses and should be analysed separately in future studies.

Proton Image-guided Radiation Assignment for Therapeutic Escalation via Selection of locally advanced head and neck cancer patients [PIRATES]: A Phase I safety and feasibility trial of MRI-guided adaptive particle radiotherapy

INTRODUCTION

Radiation dose-escalation for head and neck cancer (HNC) patients aiming to improve cure rates is challenging due to the increased risk of unacceptable treatment-induced toxicities. With "Proton Image-guided Radiation Assignment for Therapeutic Escalation via Selection of locally advanced head and neck cancer patients" (PIRATES), we present a novel treatment approach that is designed to facilitate dose-escalation while minimizing the risk of dose-limiting toxicities for locally advanced HPV-negative HNC patients. The aim of this Phase I trial is to assess the safety & feasibility of PIRATES approach.

METHODS

The PIRATES protocol employs a multi-faceted dose-escalation approach to minimize the risk of dose-limiting toxicities (DLTs): 1) sparing surrounding normal tissue from extraneous dose with intensity-modulated proton therapy, 2) mid-treatment hybrid hyper-fractionation for radiobiologic normal tissue sparing; 3) Magnetic Resonance Imaging (MRI) guided mid-treatment boost volume adaptation, and 4) iso-effective restricted organ-at-risk dosing to mucosa and bone tissues.The time-to-event Bayesian optimal interval (TITE-BOIN) design is employed to address the challenge of the long DLT window of 6 months and find the maximum tolerated dose. The primary endpoint is unacceptable radiation-induced toxicities (Grade 4, mucositis, dermatitis, or Grade 3 myelopathy, osteoradionecrosis) occurring within 6 months following radiotherapy. The second endpoint is any grade 3 toxicity occurring in 3-6 months after radiation.

DISCUSSION

The PIRATES dose-escalation approach is designed to provide a safe avenue to intensify local treatment for HNC patients for whom therapy with conventional radiation dose levels is likely to fail. PIRATES aims to minimize the radiation damage to the tissue surrounding the tumor volume with the combination of proton therapy and adaptive radiotherapy and within the high dose tumor volume with hybrid hyper-fractionation and not boosting mucosal and bone tissues. Ultimately, if successful, PIRATES has the potential to safety increase local control rates in HNC patients with high loco-regional failure risk.Trial registration: ClinicalTrials.gov ID: NCT04870840; Registration date: May 4, 2021.Netherlands Trial Register ID: NL9603; Registration date: July 15, 2021.

Stereotactic body ablative radiotherapy for reirradiation of small volume head and neck cancers is associated with prolonged survival: Large, single-institution, modern cohort study

BACKGROUND

Recurrent head and neck cancer has poor prognosis. Stereotactic body radiotherapy (SBRT) may improve outcomes by delivering ablative radiation doses.

METHODS

We reviewed patients who received definitive-intent SBRT reirradiation at our institution from 2013 to 2020. Patterns of failure, overall survival (OS), and toxicities were analyzed.

RESULTS

One hundred and thirty-seven patients were evaluated. The median OS was 44.3 months. The median SBRT dose was 45 Gy and median target volume 16.9 cc. The 1-year local, regional, and distant control was 78%, 66%, and 83%, respectively. Systemic therapy improved regional (p = 0.004) and distant control (p = 0.04) in nonmetastatic patients. Grade 3+ toxicities were more common at mucosal sites (p = 0.001) and with concurrent systemic therapy (p = 0.02).

CONCLUSIONS

In a large cohort of SBRT reirradiation for recurrent, small volume head and neck cancers, a median OS of 44.3 months was observed. Systemic therapy improved regional and distant control. Toxicities were modulated by anatomic site and systemic therapy.

Elective neck dissection versus observation in patients with head and neck cutaneous squamous cell carcinoma

BACKGROUND

The survival benefit of elective neck dissection (END) for patients with cutaneous squamous cell carcinoma (cSCC) of the head and neck and no evidence of regional metastasis (cN0) has never been reported. The aim of this study was to determine the effect of END on patient survival.

METHODS

The authors included patients with head and neck cSCC who had undergone primary surgery from 1995 to 2017. The primary end point was survival, and the secondary end points were the incidence of occult regional disease and regional disease control. To assess the impact of END on survival, the authors used multivariable Cox proportional hazards models with propensity score and matching techniques for internal validation.

RESULTS

A total of 1111 patients presented with no evidence of nodal disease; 173 had END, and 938 were observed. Adjuvant radiotherapy to the neck was administered to 101 patients (9%). END resulted in a 5-year overall survival rate of 52%, whereas the rate was 63% in the observation group (P = .003 [log-rank]). The 5-year disease-free survival rate for patients undergoing END was similar to that for the observation group (73% vs 75%; P = .429). A multivariate regression model showed that the performance of END was not associated with improved rates of overall, disease-specific, or disease-free survival; similarly, among patients with advanced disease (T3-4), those who underwent END did not have improved survival rates.

CONCLUSIONS

Among patients with cSCC of the head and neck, observation of the neck nodes resulted in noninferior survival rates in comparison with END at the time of primary surgery. Further studies are required to elucidate the role of END in patients with advanced disease.

Temporal Bone Osteoradionecrosis: An 18-year, Single-Institution Experience

OBJECTIVES/HYPOTHESIS

To report the largest single-institution review of temporal bone osteoradionecrosis (TBORN), and characterize the disease's natural history, prognostic factors, management, and outcomes.

STUDY DESIGN

Retrospective chart review.

METHODS

Retrospective review was conducted to identify patients with TBORN. Pertinent data were extracted. Descriptive statistics were used to summarize patient, tumor, and treatment characteristics. Multivariable analyses were conducted to explore associations between these characteristics and time to TBORN diagnosis and risk of developing diffuse disease.

RESULTS

TBORN was identified in 145 temporal bones from 128 patients. Mean age at diagnosis was 62 years, and mean time to diagnosis after radiotherapy was 10 years. Age greater than 50 years was associated with earlier diagnosis. According to the Ramsden criteria, 76% of TBs had localized and 24% had diffuse disease at initial diagnosis; 37% had diffuse disease at last follow-up. On multivariable analysis, diabetes, three-dimensional conformal radiotherapy (3D-CRT), and periauricular skin malignancy were significant risk factors for developing diffuse disease. Localized disease was successfully managed with conservative measures, whereas surgery was often necessary for diffuse disease. When TBORN spread outside the mastoid or infratemporal fossa, conservative measures were always unsuccessful.

CONCLUSIONS

TBORN occurs earlier in older patients. While diffuse disease is less common than localized disease, it occurs more frequently in patients with diabetes, history of 3D-CRT, and periauricular skin malignancies. Conservative management is appropriate for localized disease, while surgery is often necessary for diffuse disease. The prognostic factors identified helped propose a TBORN staging system and treatment guidelines which may improve patient risk stratification and disease management.

LEVEL OF EVIDENCE

IV Laryngoscope, 2021.

Proton Therapy for Head and Neck Cancer: A 12-Year, Single-Institution Experience

PURPOSE

To characterize our experience and the disease control and toxicity of proton therapy (PT) for patients with head and neck cancer (HNC).

PATIENTS AND METHODS

Clinical outcomes for patients with HNC treated with PT at our institution were prospectively collected in 2 institutional review board-approved prospective studies. Descriptive statistics were used to summarize patient characteristics and outcomes. Overall survival, local-regional control, and disease-free survival were estimated by the Kaplan-Meier method. Treatment-related toxicities were recorded according to the Common Terminology Criteria for Adverse Events (version 4.03) scale.

RESULTS

The cohort consisted of 573 patients treated from February 2006 to June 2018. Median patient age was 61 years. Oropharynx (33.3%; n = 191), paranasal sinus (11%; n = 63), and periorbital tissues (11%; n = 62) were the most common primary sites. Patients with T3/T4 or recurrent disease comprised 46% (n = 262) of the cohort. The intent of PT was definitive in 53% (n = 303), postoperative in 37% (n = 211), and reirradiation in 10% (n = 59). Median dose was 66 Gy (radiobiological equivalent). Regarding systemic therapy, 43% had received concurrent (n = 244), 3% induction (n = 19), and 15% (n = 86) had both. At a median follow-up of 2.4 years, 88 patients (15%) had died and 127 (22%) developed disease recurrence. The overall survival, local-regional control, and disease-free survival at 2 and 5 years were, respectively, 87% and 75%, 87% and 78%, and 74% and 63%. Maximum toxicity (acute or late) was grade 3 in 293 patients (51%), grade 2 in 234 patients (41%), and grade 1 in 31 patients (5%). There were 381 acute grade 3 and 190 late grade 3 unique toxicities across 212 (37%) and 150 (26%) patients, respectively. There were 3 late-grade 4 events across 2 patients (0.3%), 2 (0.3%) acute-grade 5, and no (0%) late-grade 5 events.

CONCLUSIONS

The overall results from this prospective study of our initial decade of experience with PT for HNC show favorable disease control and toxicity outcomes in a multidisease-site cohort and provide a reference benchmark for future comparison and study.

Outcomes of patients with oropharyngeal squamous cell carcinoma treated with induction chemotherapy followed by concurrent chemoradiation compared with those treated with concurrent chemoradiation

BACKGROUND

Induction chemotherapy (IC) has been associated with a decreased risk of distant metastasis in locally advanced head and neck squamous cell carcinoma. However, its role in the treatment of oropharyngeal squamous cell carcinoma (OPSCC) is not well established.

METHODS

The outcomes of patients with OPSCC treated with IC followed by concurrent chemoradiation (CRT) were compared with the outcomes of those treated with CRT alone. The primary outcome was overall survival (OS), and the secondary end points were the times to locoregional and distant recurrence.

RESULTS

In an existing database, 585 patients met the inclusion criteria: 137 received IC plus CRT, and 448 received CRT. Most patients were positive for human papillomavirus (HPV; 90.9%). Patients receiving IC were more likely to present with a higher T stage, a higher N stage, and low neck disease. The 3-year OS rate was significantly lower in patients receiving IC (75.7%) versus CRT alone (92.9%). In a multicovariate analysis, receipt of IC (adjusted hazard ratio [aHR], 3.4; P < .001), HPV tumor status (aHR, 0.36; P = .002), and receipt of concurrent cetuximab (aHR, 2.7; P = .002) were independently associated with OS. The risk of distant metastasis was also significantly higher in IC patients (aHR, 2.8; P = .001), whereas an HPV-positive tumor status (aHR, 0.44; P = .032) and completion of therapy (aHR, 0.51; P = .034) were associated with a lower risk of distant metastasis. In HPV-positive patients, IC remained associated with distant metastatic progression (aHR, 2.6; P = .004) but not OS.

CONCLUSIONS

In contrast to prior studies, IC was independently associated with worse OS and a higher risk of distant metastasis in patients with OPSCC. Future studies are needed to validate these findings.

The impact of induction and/or concurrent chemoradiotherapy on acute and late patient-reported symptoms in oropharyngeal cancer: Application of a mixed-model analysis of a prospective observational cohort registry

BACKGROUND

The goal of this study was to comprehensively investigate the association of chemotherapy with trajectories of acute symptom development and late symptom recovery in patients with oropharyngeal cancer (OPC) by comparing symptom burden between induction chemotherapy followed by concurrent chemoradiotherapy (ICRT), concurrent chemo‐radiotherapy (CRT), or radiotherapy (RT) alone.

METHODS

Among a registry of 717 patients with OPC, the 28‐item patient‐reported MD Anderson Symptom Inventory–Head and Neck Module (MDASI‐HN) symptoms were collected prospectively at baseline, weekly during RT, and 1.5, 3 to 6, 12, and 18 to 24 months after RT. The effect of the treatment regimen (ICRT, CRT, and RT alone) was examined with mixed‐model analyses for the acute and late period. In the CRT cohort, the chemotherapy agent relationship with symptoms was investigated.

RESULTS

Chemoradiation (ICRT/CRT) compared with RT alone resulted in significantly higher acute symptom scores in the majority of MDASI‐HN symptoms (ie, 21 out of 28). No late symptom differences between treatment with or without chemotherapy were observed that were not attributable to ICRT. Nausea was lower for CRT with carboplatin than for CRT with cisplatin; cetuximab was associated with particularly higher scores for acute and late skin, mucositis, and 6 other symptoms. The addition of ICRT compared with CRT or RT alone was associated with a significant increase in numbness and shortness of breath.

CONCLUSION

The addition of chemotherapy to definitive RT for OPC patients was associated with significantly worse acute symptom outcomes compared with RT alone, which seems to attenuate in the late posttreatment period. Moreover, induction chemotherapy was specifically associated with worse numbness and shortness of breath during and after treatment.

LAY SUMMARY

Chemotherapy is frequently used in addition to radiotherapy cancer treatment, yet the (added) effect on treatment‐induced over time is not comprehensively investigated

This study shows that chemotherapy adds to the symptom severity reported by patients, especially during treatment

Induction/concurrent chemotherapy significantly augments patient‐reported symptom burden of radiotherapy among patients with oropharyngeal cancer, as worse acute symptom outcomes are observed compared with radiotherapy alone. Induction chemotherapy is associated with greater numbness and shortness of breath during and after treatment.

Integrating depth of invasion in T classification improves the prognostic performance of the American Joint Committee on Cancer primary tumor staging system for cutaneous squamous cell carcinoma of the head and neck

BACKGROUND

The last revision of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual included a specific system for cutaneous squamous cell carcinoma (CSCC) of the head and neck. Here, we assessed the prognostic performance of six candidate modified T-classification models in head and neck CSCC patients.

METHODS

Analysis of 916 patients with head and neck CSCC given treatment with curative intent at The University of Texas MD Anderson Cancer Center between 1995 and 2019 was performed. The main outcome was disease-specific survival (DSS), and the impact of depth of invasion (DOI) was analyzed using multivariable regression models. Candidate models were developed using the optimal DOI cut points for each AJCC T classification based on goodness of fit of the model and the simplicity of the model. Staging systems were compared using Harrell's concordance index.

RESULTS

Median age was 70 years (range, 19-97years) and median follow-up time of 22 months (range, 1-250months). The median DOI was 6.0 mm (range, 0.1-70.0 mm). The five-year DSS rate was 80.7% (95%CI, 77.4-83.7%). We found significant association between DOI (hazard ratio, 1.21 [95%CI: 1.01-1.43]) and DSS on multivariable analysis. Based on a low Akaike information criterion score, improvement in the concordance index, and Kaplan-Meier curves, model 6 surpassed the AJCC staging system.

CONCLUSIONS

Incorporation of DOI in the current AJCC staging system improves discrimination of T classifications in head and neck CSCC patients.

LAY SUMMARY

The current staging system for head and neck cutaneous squamous cell carcinoma demonstrates wide prognostic variability and provides suboptimal risk stratification. Incorporation of depth of invasion in the T-classification system improves risk prediction and patient counseling.

PRECIS

We propose improved head and neck cutaneous squamous cell carcinoma T staging that will include depth of invasion and should be considered in future versions of the American Joint Committee on Cancer after external validation.

Outcomes after salvage for HPV-positive recurrent oropharyngeal cancer treated with primary radiation

PURPOSE

HPV-positive oropharyngeal squamous cell carcinoma (OPSCC) carries a favorable prognosis for patients, yet nearly 30% of patients will experience disease relapse. We sought to detail patterns of failure, associated salvage therapy, and outcomes for patients with recurrent HPV-positive OPSCC.

METHODS AND MATERIALS

This is a single institution retrospective study of patients with recurrent HPV-positive OPSCC irradiated from 2002 to 2014. The primary study outcome was overall survival (OS, calculated using the Kaplan-Meier method). Secondary aims included patterns of first failure with descriptive details of salvage therapy. Solitary recurrences were defined as initial presentation of recurrence in a single site (primary, neck or oligometastatic), and multi-site was defined as local and regional and/or multiple sites of distant recurrence. Survival outcomes were compared using the log-rank test.

RESULTS

The cohort consisted of 132 patients. The median follow-up was 59 months for surviving patients. Estimated 2-year and 5-year OS rates were 47% and 32%, respectively. Comparative 2-year and 5-year OS rates were 65% and 46% versus 19% and 9% for the solitary group and multi-site group, respectively (p < .001).

CONCLUSIONS

Patients with recurrent HPV-positive OPSCC experience 5-year survival of approximately 32%. However, patients with a "solitary" recurrence including disease at the primary site, neck or oligometastatic site have more favorable long-term outcomes.

Inclusion of extranodal extension in the lymph node classification of cutaneous squamous cell carcinoma of the head and neck

BACKGROUND

The prognostic performance of the recently updated American Joint Committee on Cancer lymph node classification of cutaneous head and neck squamous cell carcinoma (HNSCC) has not been validated. The objective of this study was to assess the prognostic role of extranodal extension (ENE) in cutaneous HNSCC.

METHODS

This was a retrospective analysis of 1258 patients with cutaneous HNSCC who underwent surgery with or without adjuvant therapy between 1995 and 2019 at The University of Texas MD Anderson Cancer Center. The primary outcome was disease-specific survival (DSS). Local, regional, and distant metastases-free survival were secondary outcomes. Recursive partitioning analysis (RPA) and a Cox proportional hazards regression model were used to assess the fitness of staging models.

RESULTS

No significant differences in 5-year DSS were observed between patients with pathologic lymph node-negative (pN0) disease (67.4%) and those with pN-positive/ENE-negative disease (68.2%; hazard ratio, 1.02; 95% CI, 0.61-1.79) or between patients with pN-positive/ENE-negative disease and those with pN-positive/ENE-positive disease (52.7%; hazard ratio, 0.57; 95% CI, 0.31-1.01). The RPA-derived model achieved better stratification between high-risk patients (category III, ENE-positive with >2 positive lymph nodes) and low-risk patients (category I, pN0; category II, ENE-positive/pN1 and ENE-negative with >2 positive lymph nodes). The performance of the RPA-derived model was better than that of the pathologic TNM classification (Akaike information criterion score, 1167 compared with 1176; Bayesian information criterion score, 1175 compared with 1195).

CONCLUSIONS

The number of metastatic lymph nodes and the presence of ENE are independent prognostic factors for DSS in cutaneous HNSCC, and incorporation of these factors in staging systems improves the performance of the American Joint Committee on Cancer lymph node classification.

Defining the dose-volume criteria for laryngeal sparing in locally advanced oropharyngeal cancer utilizing split-field IMRT, whole-field IMRT and VMAT

PURPOSE

To determine the optimal dose-volume constraint for laryngeal sparing using three commonly employed intensity modulated radiation therapy (IMRT) approaches in patients with oropharyngeal cancer treated to the bilateral neck.

MATERIALS AND METHODS

Thirty patients with stage II-IVA oropharynx cancers received definitive radiotherapy with split-field IMRT (SF-IMRT) to the bilateral neck between 2008 and 2013. Each case was re-planned using whole-field IMRT (WF-IMRT) and volumetric modulated arc therapy (VMAT) and plan quality metrics and dose to laryngeal structures was evaluated. Two larynx volumes were defined and compared on the current study: the Radiation Therapy Oncology Group (RTOG) larynx as defined per the RTOG 1016 protocol and the MDACC larynx defined as the components of the larynx bounded by the superior and inferior extent of the thyroid cartilage.

RESULTS

Target coverage, conformity, and heterogeneity indices were similar in all techniques. The RTOG larynx mean dose was lower with WF-IMRT than SF-IMRT (22.1 vs 25.8 Gy; P < 0.01). The MDACC larynx mean dose was 17.5 Gy ± 5.4 Gy with no differences between the 3 techniques. WF-IMRT and VMAT plans were associated with lower mean doses to the supraglottic larynx (42.1 vs 41.2 vs 54.8 Gy; P < 0.01) and esophagus (18.1 vs 18.2 vs 36 Gy; P < 0.01).

CONCLUSIONS

Modern whole field techniques can provide effective laryngeal sparing in patients receiving radiotherapy to the bilateral neck for advanced oropharyngeal cancers.

SUMMARY

We evaluated laryngeal dose in patients with locally advanced oropharyngeal cancer treated to the bilateral neck using split-field IMRT (SF-IMRT), whole-field IMRT (WF-IMRT) and volumetric arc therapy (VMAT). All three techniques provided good sparing of laryngeal structures and were able to achieve a mean larynx dose < 33 Gy. There were no significant differences in dose to target structures or non-laryngeal organs at risk among techniques.

Highly conformal reirradiation in patients with prior oropharyngeal radiation: Clinical efficacy and toxicity outcomes

BACKGROUND

Reirradiation of head and neck cancer is associated with high rates of locoregional failure and potentially severe treatment-related toxicity. We report our institutional experience of reirradiation using modern highly conformal radiotherapy approaches in patients with prior oropharyngeal radiation.

METHODS

We reviewed patients receiving curative-intent reirradiation with intensity-modulated radiation therapy, stereotactic body radiation therapy, and proton beam radiotherapy at our institution from 1999 to 2019. Disease control, survival, and toxicity rates following reirradiation were determined.

RESULTS

Sixty-nine patients were evaluated. Local control (LC), progression-free survival, and overall survival at 2 years following reirradiation were 77%, 35%, and 51%, respectively. Grade 3 or greater (G3+) late toxicities occurred in 46% of patients and 41% required feeding tube placement during or after reirradiation.

CONCLUSIONS

In select patients with prior oropharyngeal radiation, highly conformal reirradiation offers acceptable LC, but G3+ toxicity and out-of-field failure rates remain high. These findings warrant continued evaluation of new multimodality approaches to improve oncologic outcomes.

Effect of Deep Inspiration Breath Hold on Normal Tissue Sparing With Intensity Modulated Radiation Therapy Versus Proton Therapy for Mediastinal Lymphoma

Purpose

Intensity modulated radiation therapy delivered with deep-inspiration breath hold (IMRT-BH) provides favorable normal tissue dosimetric profiles when treating patients with mediastinal lymphoma. However, it is unclear if IMRT-BH plans are comparable to free breathing (FB) proton plans. We performed a retrospective, comparative dosimetric study between IMRT-BH and FB passive scatter proton therapy (P-FB) or intensity modulated proton therapy (IMPT-FB). Hypothesizing that BH would provide superior normal tissue sparing when added to proton therapy, we also compared plans to passive scatter BH (P-BH).

Methods and Materials

For 15 patients who received involved-site RT with "butterfly" IMRT-BH, 3 additional proton plans (P-FB, IMPT-FB, P-BH) were optimized to deliver 30.6 Gy/Gy relative biological effectiveness. Dosimetric variables (mean dose, V30, V25, V15, and V5) for organs at risk (OARs) were calculated and compared using nonparametric Wilcoxon signed-rank tests.

Results

Of 57 studied OAR parameters, IMRT-BH plans were comparable in 37 (65%) parameters with P-FB plans, 32 (56%) of IMPT-FB parameters, and 30 (53%) of P-BH parameters. Doses to breasts were generally equivalent among plans while esophageal dosing was worse with IMRT-BH. Mean doses and V5 of the total lung and heart were the highest with IMRT-BH; however, IMRT-BH resulted in comparable coronary and superior lung V30 relative to proton plans. The addition of BH with proton therapy resulted in the greatest lung sparing, with mean lung dose reductions of 11% to 38%.

Conclusions

The use of BH with IMRT reduces the disparity in OAR doses with equivalence achieved in nearly two-thirds of OAR metrics compared with P-FB and 50% compared with IMPT-BH. Because each modality exhibited unique benefits, personalization of modality selection is recommended. Proton therapy via BH provides additional benefits in heart and lung sparing.

A Dosimetric Comparison of Oral Cavity Sparing in the Unilateral Treatment of Early Stage Tonsil Cancer: IMRT, IMPT, and Tongue-Deviating Oral Stents

Introduction

Tongue-deviating oral stents (TDOS) are commonly used during unilateral neck radiation therapy to reduce unnecessary dose to nontarget oral structures. Their benefit in the setting of highly conformal treatment techniques, however, is not defined. The goal of this study was to investigate the potential benefit of TDOS use on dosimetric parameters in unilateral intensity modulated radiation therapy (IMRT) and intensity modulated proton therapy (IMPT).

Methods

A total of 16 patients with T1-2 tonsil cancer treated at a single institution were selected, of which 8 were simulated/treated with a TDOS and 8 without a TDOS. All received definitive unilateral IMRT to a dose of 66 Gy in 30 fx. IMPT plans were generated for each patient for study purposes and optimized according to standard institutional practice.

Results

For IMRT plans, the presence of a TDOS (vs without) was associated with a significantly lower oral mucosa mean dose (31.4 vs 35.3 Gy; P = .020) and V30 (42.7% vs 57.1%; P = .025). For IMPT plans, the presence of TDOS (vs without) was not associated with any improvement in oral mucosa mean dose (18.3 vs 19.9 Gy; P = .274) or V30 (25.0% vs 26.2%; P = .655). IMPT plans without TDOS compared with IMRT plans with TDOS demonstrated reduced oral mucosa mean dose (P < .001) and V30 (P < .001).

Conclusion

The use of a TDOS for the unilateral treatment of well-lateralized tonsil cancers was associated with oral mucosa sparing for IMRT, but not for IMPT. Moreover, mucosa sparing was improved for IMPT plans without a TDOS compared to IMRT plans with a TDOS.

Predicting Incomplete Resection in Non-Small Cell Lung Cancer Preoperatively: A Validated Nomogram

BACKGROUND

Patients who are surgically treated for stage I to III non-small cell lung cancer (NSCLC) have dismal prognosis after incomplete (R1-R2) resection. Our study aimed to develop a prediction model to estimate the chance of incomplete resection based on preoperative patient-, tumor-, and treatment-related factors.

METHODS

From a Dutch national cancer database, NSCLC patients who had surgical treatment without neoadjuvant therapy were selected. Thirteen possible predictors were analyzed. Multivariable logistic regression was used to create a prediction model. External validation was applied in the American National Cancer Database, whereupon the model was adjusted. Discriminatory ability and calibration of the model was determined after internal and external validation. The prediction model was presented as nomogram.

RESULTS

Of 7156 patients, 511 had an incomplete resection (7.1%). Independent predictors were histology, cT stage, cN stage, extent of surgery, and open vs thoracoscopic approach. After internal validation, the corrected C statistic of the resulting nomogram was 0.72. Application of the nomogram to an external data set of 85,235 patients with incomplete resection in 2485 patients (2.9%) resulted in a C statistic of 0.71. Calibration revealed good overall fit of the nomogram in both cohorts.

CONCLUSIONS

An internationally validated nomogram is presented providing the ability to predict the individual chance of incomplete resection in patients with stage I to III NSCLC planned for resection. In case of a high predicted risk of incomplete resection, alternative treatment strategies could be considered, whereas a low risk further supports the use of surgical procedures.

Prospective longitudinal patient-reported outcomes of swallowing following intensity modulated proton therapy for oropharyngeal cancer

BACKGROUND AND PURPOSE

With an enlarging population of long-term oropharyngeal cancer survivors, dysphagia is an increasingly important toxicity following oropharynx cancer treatment. While lower doses to normal surrounding structures may be achieved with intensity modulated proton therapy (IMPT) compared to photon-based radiation, the clinical benefit is uncertain.

METHODS AND MATERIALS

Seventy-one patients with stage III/IV oropharyngeal cancer (AJCC 7th edition) undergoing definitive IMPT on a longitudinal prospective cohort study who had completed the MD Anderson Dysphagia Inventory (MDADI) at pre-specified time points were included.

RESULTS

The majority of patients had HPV-positive tumors (85.9%) and received bilateral neck radiation (81.4%) with concurrent systemic therapy (61.8%). Mean composite MDADI scores decreased from 88.2 at baseline to 59.6 at treatment week 6, and then increased to 74.4 by follow up week 10, 77.0 by 6 months follow up, 80.5 by 12 months follow up, and 80.1 by 24 months follow up. At baseline, only 5.6% of patients recording a poor composite score (lower than 60), compared to 61.2% at treatment week 6, 19.1% at follow up week 10, 13.0% at 6 months follow up, 13.5% at 1 year follow up, and 11.1% at 2 years follow up.

CONCLUSIONS

Patient reported outcomes following IMPT for oropharyngeal cancer demonstrates decreased swallowing function at completion of treatment with relatively rapid recovery by 10 weeks follow up and steady improvement through 2 years. The results are comparable to similar longitudinal studies of photon-based radiotherapy for oropharynx cancer, and suggest that IMPT confers no additional excess toxicity related to swallowing.

Comparison of tumor delineation using dual energy computed tomography versus magnetic resonance imaging in head and neck cancer re-irradiation cases

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GTVs on the 60 kV and 140 kV from DECT, and the T1c and T2 from MRI were compared.

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Delineation was the most consistent using T1c (no interobserver difference in DSC).

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T1c MRI provided higher interobserver agreement for skull base tumors.

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60 kV DECT provided higher interobserver agreement for non-skull base tumors.

In treatment planning, multiple imaging modalities can be employed to improve the accuracy of tumor delineation but this can be costly. This study aimed to compare the interobserver consistency of using dual energy computed tomography (DECT) versus magnetic resonance imaging (MRI) for delineating tumors in the head and neck cancer (HNC) re-irradiation scenario. Twenty-three patients with recurrent HNC and had planning DECT and MRI were identified. Contoured tumor volumes by seven radiation oncologists were compared. Overall, T1c MRI performed the best with median DSC of 0.58 (0–0.91) for T1c. T1c MRI provided higher interobserver agreement for skull base sites and 60 kV DECT provided higher interobserver agreement for non-skull base sites.

Post-treatment mortality after definitive chemoradiotherapy versus resection for esophageal cancer

In efforts to better characterize incidence and predictors of 30- and 90-day mortality following operative versus nonoperative approaches for locally advanced esophageal cancer (EC), we conducted a novel investigation of a large, contemporary US database. The National Cancer Database was queried for newly-diagnosed T1-3N0-1 squamous cell or adenocarcinoma receiving surgical-based therapy (esophagectomy alone or preceded by chemotherapy and/or radiotherapy) versus definitive chemoradiotherapy (dCRT). Statistics included graphing cumulative incidences of mortality before and following propensity score matching (PSM), based on age-based intervals. Cox regression determined factors independently predictive of 30- and 90-day mortality. Of 15,585 patients, 9,278 (59.5%) received surgical-based therapy and 6,307 (40.5%) underwent dCRT. In the unadjusted population, despite nonsignificant differences at 30 days (3.3% dCRT, 3.6% surgical-based), the dCRT cohort experienced higher 90-day mortality (11.0% vs. 7.5%, P < 0.001). Following PSM, however, dCRT patients experienced significantly lower 30-day mortality (P < 0.001), with nonsignificant differences at 90 days (P = 0.092). Surgical-based management yielded similar (or better) mortality as dCRT in ≤70-year-old patients; however, dCRT was associated with reduced mortality in subjects > 70 years old. In addition to the intervention group, factors predictive for 30- and 90-day mortality included age, gender, insurance status, facility type, comorbidity index, tumor location, histology, and T/N classification. In summary, surgical-based therapy for EC is associated with higher 30-day mortality, which becomes statistically similar to dCRT by 90 days. Differences between surgery and dCRT were most pronounced in patients > 70 years of age. These data may better inform shared decision-making between multidisciplinary providers and patients.

Outcomes after Treatment of Metaplastic Versus Other Breast Cancer Subtypes

Purpose: Metaplastic breast cancer (BC) is an uncommon yet aggressive histologic subtype of BC. We sought to identify factors associated with its diagnosis and compare the management and outcomes of metaplastic BC with those of other BCs and triple negative invasive ductal carcinoma in particular given how often it has a triple negative phenotype. Patients and Methods: We identified women diagnosed with invasive BC in 2010-2014 in the National Cancer Data Base, and used univariate analysis to compare baseline patient and tumor characteristics by BC subtype. Overall survival (OS) was estimated with the Kaplan-Meier method, and multivariate Cox proportional hazards models were used to identify independent predictors of OS. Results: Of 247,355 cases, 2,084 (0.8%) were metaplastic BC, 55,998 (23%) triple negative BC, and 77% other BC. Relative to non-metaplastic BC, women with metaplastic BC were more likely to be older at diagnosis (median age, 62 vs. 59 years), have ≥1 comorbid conditions (22% vs. 18%), and be on Medicare (41% vs. 33%; P<0.001). Metaplastic BCs tended to be basal-like (77%), and relative to triple-negative or other BC, metaplastic BC was associated with higher clinical T status (cT3-4, 18% vs. 11%, 8%), no clinical nodal involvement (cN0, 86%, 77%, 80%), no lymphovascular invasion (72%, 65%, 62%), and high-grade tumors (71%, 77%, 35%) (P<0.001). Most metaplastic BCs were treated with mastectomy (58%), sentinel lymph node dissection (65%), chest wall or breast irradiation (74%), and chemotherapy (75%) as adjuvant therapy (60%). At a median follow-up time of 44.5 months, OS rates were lower for metaplastic BC than for triple-negative or other BC across all clinical stages at 5 years (stage I, 85%, 87%, 91%; II, 73%, 77%, 87%; III, 43%, 53%, 75%) and at 3 years (Stage IV, 15%, 22%, 64%; P<0.001). On multivariate analysis, increasing age, advanced clinical stage, lymphovascular invasion, axillary (vs. sentinel) node dissection, and no radiation or chemotherapy were associated with worse outcomes in metaplastic BC. Extent of surgery affected survival for triple-negative and other BC but not for metaplastic BC. Conclusion: Outcomes for metaplastic BC continue to be worse than those for other BC subtypes despite modern treatments. Optimizing systemic therapy options, which was a significant predictor of survival, should be a priority in managing metaplastic BC.

Estimating PTV Margins in Head and Neck Stereotactic Ablative Radiation Therapy (SABR) Through Target Site Analysis of Positioning and Intrafractional Accuracy

PURPOSE

Recurrent or previously irradiated head and neck cancers (HNC) are therapeutically challenging and may benefit from high-dose, highly accurate radiation techniques, such as stereotactic ablative radiation therapy (SABR). Here, we compare set-up and positioning accuracy across HNC subsites to further optimize the treatment process and planning target volume (PTV) margin recommendations for head and neck SABR.

METHODS AND MATERIALS

We prospectively collected data on 405 treatment fractions across 79 patients treated with SABR for recurrent/previously irradiated HNC. First, interfractional error was determined by comparing ExacTrac x-ray to the treatment plan. Patients were then shifted and residual error was measured with repeat x-ray. Next, cone beam computed tomography (CBCT) was compared with ExacTrac for positioning agreement, and final shifts were applied. Lastly, intrafractional error was measured with x-ray before each arc. Results were stratified by treatment site into skull base, neck/parotid, and mucosal.

RESULTS

Most patients (66.7%) were treated to 45 Gy in 5 fractions (range, 21-47.5 Gy in 3-5 fractions). The initial mean ± standard deviation interfractional errors were -0.2 ± 1.4 mm (anteroposterior), 0.2 ± 1.8 mm (craniocaudal), and -0.1 ± 1.7 mm (left-right). Interfractional 3-dimensional vector error was 2.48 ± 1.44, with skull base significantly lower than other sites (2.22 vs 2.77; P = .0016). All interfractional errors were corrected to within 1.3 mm and 1.8°. CBCT agreed with ExacTrac to within 3.6 mm and 3.4°. CBCT disagreements and intrafractional errors of >1 mm or >1° occurred at significantly lower rates in skull base sites (CBCT: 16.4% vs 50.0% neck, 52.0% mucosal, P < .0001; intrafractional: 22.0% vs 48.7% all others, P < .0001). Final PTVs were 1.5 mm (skull base), 2.0 mm (neck/parotid), and 1.8 mm (mucosal).

CONCLUSIONS

Head and neck SABR PTV margins should be optimized by target site. PTV margins of 1.5 to 2 mm may be sufficient in the skull base, whereas 2 to 2.5 mm may be necessary for neck and mucosal targets. When using ExacTrac, skull base sites show significantly fewer uncertainties throughout the treatment process, but neck/mucosal targets may require the addition of CBCT to account for positioning errors and internal organ motion.

Biologically Effective Dose in Stereotactic Body Radiotherapy and Survival for Patients With Early-Stage NSCLC

INTRODUCTION

Stereotactic body radiotherapy (SBRT) results in excellent local control of stage I NSCLC. Radiobiology models predict greater tumor response when higher biologically effective doses (BED₁₀) are given. Prior studies support a BED₁₀ greater than or equal to 100 Gy with SBRT; however, data are limited comparing outcomes after various SBRT regimens. We therefore sought to evaluate national trends and the effect of using "low" versus "high" BED₁₀ SBRT courses on overall survival (OS).

METHODS

This retrospective study used the National Cancer Data Base to identify patients diagnosed with clinical stage I (cT1-2aN0M0) NSCLC from 2004 to 2014 treated with SBRT. Patients were categorized into LowBED (100-129 Gy) or HighBED (≥130 Gy) groups. A 1:1 matched analysis based on patient and tumor characteristics was used to compare OS by BED₁₀ group. Tumor centrality was not assessed.

RESULTS

O 25,039 patients treated with LowBED (n = 14,756; 59%) or HighBED (n = 10,283; 41%) SBRT, 20,542 were matched. Shifts in HighBED to LowBED SBRT regimen use correlated with key publications in the literature. In the matched cohort, 5-year OS rates were 26% for LowBED and 34% for HighBED groups (p = 0.039). On multivariate analysis, receipt of LowBED was associated with significantly worse survival (hazard ratio = 1.046, 95% confidence interval: 1.004-1.090, p = 0.032).

CONCLUSIONS

LowBED SBRT for treating stage I NSCLC is becoming more common. However, our findings suggest SBRT regimens with BED₁₀ greater than or equal to 130 Gy may confer an additional survival benefit. Additional studies are required to evaluate the dose-response relationship and toxicities associated with modern HighBED SBRT.

Sequential Versus Concurrent Chemoradiation Therapy by Surgical Margin Status in Resected Non-Small Cell Lung Cancer

Background: Postoperative chemoradiotherapy (CRT) for non-small cell lung cancer (NSCLC) can be delivered sequentially (sCRT) or concurrently (cCRT). Without high-volume data, current guidelines recommend either option for patients with negative margins (M-) and cCRT for those with positive margins (M+). In this study, survival was compared between sCRT versus cCRT for M- and M+ disease; survival in patients who underwent sCRT was also assessed with chemotherapy-first versus radiotherapy (RT)-first. Methods: The National Cancer Database was queried for patients with primary NSCLC undergoing surgery followed by CRT. Patients were excluded if they received neoadjuvant chemotherapy or RT. Both M- and M+ (including R1 and R2) subcohorts were evaluated. Multivariable logistic regression ascertained factors associated with cCRT delivery. Kaplan-Meier analysis evaluated overall survival (OS); Cox proportional hazards modeling determined variables associated with OS. Propensity score matching aimed to address group imbalances and indication biases. Results: Of 4,921 total patients, 3,475 (71%) were M-, 1,446 (29%) were M+, 2,271 (46%) received sCRT, and 2,650 (54%) underwent cCRT. Median OS among the sCRT and cCRT groups in patients who were M- was 54.6 versus 39.5 months, respectively (P<.001); differences persisted following propensity score matching (P<.001). In the overall M+ cohort, outcomes for sCRT and cCRT were 36.3 versus 30.5 months (P=.011), but showed equipoise following matching (P=.745). In the R1 and R2 subsets, no differences in OS were seen between cohorts (P=.368 and .553, respectively). When evaluating the sCRT population, there were no OS differences between chemotherapy-first and RT-first after matching (P=.229). Conclusions: Postoperative sCRT was associated with improved survival compared with cCRT in patients with M- disease, with statistical equipoise in those with M+ disease. Differential sequencing of sCRT does not appear to affect survival.

P2269IABP-SHOCK II risk score validation for cardiogenic shock after myocardial infarction in a cohort treated with pharmaco-invasive therapy

Background

Risk stratification using scores is a valuable tool in cardiogenic shock after ST elevation myocardial infarction (STEMI). During pharmacoinvasive therapy (PIT) their use is unexplored in the literature. Objective: To validate the IABP-SHOCK II (Intra-aortic Balloon Pump in Cardiogenic Shock) score in patients treated with PIT and to analyze the influence of ischemia time on the different risk strata.

Methods and results

Of 2,143 STEMI patients seen between May 2010 and April 2017, 212 (9.9%) developed cardiogenic shock. Thirty-one patients (14.6%) with incomplete data were excluded from the analysis and the validation cohort included the remaining 181. Mortality rates were similar between the analyzed and excluded patients (42.5% and 45.1% respectively, p=0.77). The 30-day mortality using the IABP-SHOCK II score was 26.6% for low-risk (n=94), 53.2% for moderate-risk (n=62), and 76% for high-risk (n=25) (p<0.001). The validation of the score showed good discrimination for death, with an area under the curve of 0.73 (95% confidence interval 0.66 to 0.81 p<0.001). Although pain-to-needle time was significantly longer in patients who died within 30 days (251 min, interquartile range 140–528 vs. 210 min, interquartile range 130–343, p=0.032), the median intervals of pain-to-needle and fibrinolytic-catheterization showed no association with the group stratification (220 vs 251 vs 200 min; p=0.22 and 390 vs 435 vs 315 min; p=0.18, respectively). This finding may be explained by the potential of these variables to be more closely associated with the development of cardiogenic shock in STEMI patients treated with PIT, and to be less associated with progression to death when the patient is already in shock.

30-day mortality in scored strata

Conclusion

In patients with cardiogenic shock after STEMI treated with PIT, risk stratification using the IABP-SHOCK II score was adequate. There was no influence of pain-to-needle and fibrinolytic-catheterization times on the ability to the score model stratification.

Optimizing laryngeal sparing with intensity modulated radiotherapy or volumetric modulated arc therapy for unilateral tonsil cancer

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Early stage tonsillar cancers may be treated with unilateral neck radiotherapy (RT).

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We performed a dosimetric study comparing three common radiotherapy modalities.

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No significant differences in target coverage existed between all plans.

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Laryngeal doses were reduced using whole-field intensity modulated RT and VMAT.

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Shorter treatment times and required monitor units were also associated with VMAT.

Background and purpose

Minimizing radiation dose exposure to nearby organs is key to limiting clinical toxicities associated with radiotherapy. Several treatment modalities such as split- or whole-field intensity-modulated radiotherapy (SF-IMRT, WF-IMRT) and volumetric modulated arc therapy (VMAT) are being used to treat tonsillar cancer patients with unilateral neck radiotherapy. Herein, we provide a modern dosimetric comparison of all three techniques.

Materials and methods

Forty patients with tonsillar cancer treated with definitive, ipsilateral neck SF-IMRT were evaluated. Each patient was re-planned with WF-IMRT and VMAT techniques, and doses to selected organs-at-risk (OARs) including the larynx, esophagus, and brainstem were compared.

Results

No significant differences in target coverage existed between plans; however, the heterogeneity index improved using WF-IMRT and VMAT relative to SF-IMRT. Compared to SF-IMRT, WF-IMRT and VMAT plans had significantly lower mean doses to the supraglottic larynx (31 Gy, 18.5 Gy, 17 Gy; p < 0.01), the MDACC-defined larynx (13.4 Gy, 10.5 Gy, 9.8 Gy; p < 0.01), and RTOG-defined larynx (15.8 Gy, 12.1 Gy, 11.1 Gy; p < 0.01), respectively. Mean esophageal dose was lowest with SF-IMRT over WF-IMRT and VMAT (5.9 Gy, 12.2 Gy, 11.1 Gy; p < 0.01) but only in the absence of lower neck disease. On average, VMAT plans had shorter treatment times and required less monitor units than both SF-IMRT and WF-IMRT.

Conclusion

In the setting of unilateral neck radiotherapy, WF-IMRT and VMAT plans can be optimized to significantly improve dose sparing of critical structures compared to SF-IMRT. VMAT offers additional advantages of shorter treatment times and fewer required monitor units.