Letter to the Editor.

This is a Letter to the Editor in response to the manuscript titled, "Treatment planning for MR-guided SBRT of pancreatic tumors on a 1.5 T MR-Linac: A global consensus protocol" by Grimbergen et al.

The role of stereotactic body radiotherapy in oligoprogressive malignant disease (RADIANT): oncologic outcomes from a phase 2 non-randomized controlled trial.

BACKGROUND: In oligoprogressive (OP) cancer there are a limited numbers of metastatic areas progressing on a background of stable or responding widespread cancer. While the standard-of-care for OP is changing systemic therapy (ST), stereotactic body radiotherapy (SBRT) is being explored as an alternative local therapy targeting the sites of progression. MATERIALS/METHODS: XXX (NCTXXX) was a single-centre phase-2 study of patients with metastatic genitourinary (GU), breast and gastrointestinal (GI) cancers, receiving ST for >3 months, with radiographic OP disease in <5 sites. Patients received SBRT to all OP disease in 1-5 fractions, and were maintained on ST. The primary endpoint was the cumulative incidence of change in ST estimated using Aalen-Johansen method. Secondary endpoints included progression-free survival (PFS) and overall survival (OS) estimated using Kaplan-Meier method, toxicity, and health-related quality-of-life (HRQOL). Comparisons between diagnosis groups were done using log-rank test. A two-sided p-value of <0.05 was considered as statistical significance. RESULTS: Seventy patients were analyzed, with median age 69 years; 32 patients (46%) were female; median number of lines of prior ST was 3. Primary sites were GU (n=32; 46%), breast (n=23; 33%) and GI (n=15; 21%). Median follow-up was 12.3 months (IQR 8.2-21.6). At 1-year, change in ST occurred in 47% (95% CI 36-61%) (GU 45%, breast 41%, GI 60%, p=0.23). PFS at 1-year was 32% (95% CI 23-45%), and median PFS was 4.7 months (95% CI 3.8-8.1) (GU 4.8, breast 6.5, GI 3.2), which significantly differed by disease type (p=0.006). OS was 75% at 1-year (95% CI 65-87%), which significantly differed between cancer type (GU 86%, breast 96%, GI 22%, p<0.001). Cumulative incidence of late grade >2 toxicity was 1.2%, with 1 patient experiencing late grade 3 toxicity, and no grade 4-5 acute or late toxicities. HRQOL declined from mean (standard deviation) of 66.9 (20.2) at baseline to 60.5 (22.2) at 6 months, which did not meet the threshold for a minimal clinically important difference. CONCLUSIONS: SBRT for OP metastases delayed change in ST in approximately half of patients, warranting investigation in randomized trials.

The prognostic value of image-identified extranodal extension in laryngeal and hypopharyngeal carcinoma following definitive (chemo-)radiotherapy.

OBJECTIVES: Clinical extranodal extension (cENE) is a cN modifier in TNM-8 for laryngo-hypopharygeal carcinoma (LHC). We hypothesize that image-detected ENE (iENE) can provide additional prognostic value over cENE in LHC. METHODS: Baseline CTs/MRIs of cN+ LHC patients treated with definitive (chemo-)radiotherapy between 2010-2019 were re-reviewed by a neuroradiologist using internationally accepted criteria for iENE-positive/negative (iENE+/iENE-). Overall survival (OS) was compared by iENE status. Multivariable analysis (MVA) was performed to confirm the prognostic value of iENE, adjusted for known potential confounders. RESULTS: A total of 232 LHC patients were identified, including 154 iENE-/cENE-, 60 iENE+/cENE-, and 18 iENE+/cENE+. A higher proportion of iENE+ (vs iENE-) patients had lymph node (LN) size > 3 cm [53 (67 %) vs 4 (3 %)], >=5 LNs [51 (65 %) vs 33 (21 %)], and retropharyngeal LN [12 (15 %) vs 6 (4 %)] (all p < 0.01). Median follow-up was 4.8 years. iENE+/cENE- and iENE+/cENE+patients had similarly low 5-year OS [28 % (18-44) and 29 % (13-63)] vs iENE-/cENE- [53 % (45-62)] (p < 0.001). On MVA, mortality risk was higher with iENE+vs iENE- [hazard ratio (HR) 2.22 (95 % CI 1.47-3.36)]. The prognostic value of iENE remained with MVA in larynx (n = 124) (HR 2.51 [1.35-4.68], p = 0.004] or hypopharynx (n = 108) (HR 1.87 [1.02-3.43], p = 0.04) patients, separately. CONCLUSIONS: Our study confirms the independent prognostic importance of iENE for LHC following definitive (chemo-)radiotherapy beyond TNM-8 cN status that already contains the cENE parameter. Further research is needed to explore whether iENE could replace cENE for future cN classification.

Peer Review in Radiation Oncology: Where Does the Middle East, North Africa, and Türkiye Region Stand?

PURPOSE: This study aims to assess the status of radiation oncology peer review procedures across the Middle East, North Africa, and Türkiye (MENAT) region. METHODS: A cross-sectional electronic survey was conducted among radiotherapy centers in the MENAT region in March 2024. It assessed peer review practices, departmental demographics, perceived importance of peer review, and potential barriers. RESULTS: Data from 177 radiation oncology centers revealed varying peer review implementation across the MENAT region. Egypt had the highest participation (16.4%) among all responders. Most centers (31%) treated 500-1,000 cases annually. The majority (77.4%) implemented peer review, with varying levels between countries and across different centers. Advanced radiotherapy techniques significantly correlated with implementation of peer review (P < .05). Peer review meetings were mostly scheduled on a weekly basis (46%) and organized by radiation oncologists (84.7%). Target volume contouring (89%) and radiotherapy prescription (82%) were frequently peer-reviewed. Respondents with peer review at their institutions significantly valued peer review for education, adherence to guidelines, improving planning protocols, and reducing variation in practice institutions without peer review (P < .05). The most frequently reported barriers to peer review were having a high number of patients (56%) and shortage of time (54%). CONCLUSION: Peer review is essential for improving the quality of practice in radiation oncology. Despite some discrepancies, numerous obstacles, and challenges in implementation, it is instrumental in the improvement of patient care in most centers throughout the region. Raising awareness among radiation oncologists about the importance of peer review is paramount to lead to better outcomes.

A marginal structural model for normal tissue complication probability.

The goal of radiation therapy for cancer is to deliver prescribed radiation dose to the tumor while minimizing dose to the surrounding healthy tissues. To evaluate treatment plans, the dose distribution to healthy organs is commonly summarized as dose-volume histograms (DVHs). Normal tissue complication probability (NTCP) modeling has centered around making patient-level risk predictions with features extracted from the DVHs, but few have considered adapting a causal framework to evaluate the safety of alternative treatment plans. We propose causal estimands for NTCP based on deterministic and stochastic interventions, as well as propose estimators based on marginal structural models that impose bivariable monotonicity between dose, volume, and toxicity risk. The properties of these estimators are studied through simulations, and their use is illustrated in the context of radiotherapy treatment of anal canal cancer patients.

A multi-institutional feasibility lead-in trial of lymphatic mapping with SPECT-CT for evaluating contralateral disease in lateralized oropharynx cancer using 99m-technetium sulfur colloid.

BACKGROUND: Lymphatic mapping with SPECT-CT has been demonstrated to accurately define lymphatic drainage patterns in oropharyngeal cancer but there has yet to be a study demonstrating its feasibility across multiple institutions. METHODS: Twelve adult patients with lateralized oropharyngeal carcinoma (T1-T3) who were planned for definitive or adjuvant radiotherapy without contralateral nodal disease underwent injection of 99-m technetium sulfur colloid followed by static planar lymphoscintigraphy to verify tracer migration, and SPECT-CT acquired at 30 ± 15 min (optional) and 3 h (±1 h) (mandatory time-point). RESULTS: All 12 patients completed the study with 7/12 patients having the injections performed under local anesthetic and 5 patients requiring general anesthetic. There were no tracer migration failures and there were no serious adverse events or complications encountered. Four out of 12 patients (33%) showed contralateral drainage patterns. CONCLUSIONS: Lymphatic mapping with SPECT-CT of lateralized oropharyngeal squamous cell carcinoma can be performed safely across multiple institutions.

Development and validation of an MR-driven dose-of-the-day procedure for online adaptive radiotherapy in upper gastrointestinal cancer patients.

Objective.To develop and validate a dose-of-the-day (DOTD) treatment plan verification procedure for liver and pancreas cancer patients treated with an magnetic resonance (MR)-Linac system.Approach.DOTD was implemented as an automated process that uses 3D datasets collected during treatment delivery. Particularly, the DOTD pipeline's input included the adapt-to-shape (ATS) plan-i.e. 3D-MR dataset acquired at beginning of online session, anatomical contours, dose distribution-and 3D-MR dataset acquired during beam-on (BON). The DOTD automated analysis included (a) ATS-to-BON image intensity-based deformable image registration (DIR), (b) ATS-to-BON contours mapping via DIR, (c) BON-to-ATS contours copying through rigid registration, (d) determining ATS-to-BON dosimetric differences, and (e) PDF report generation. The DIR process was validated by two expert reviewers. ATS-plans were recomputed on BON datasets to assess dose differences. DOTD analysis was performed retrospectively for 75 treatment fractions (12-liver and 5-pancreas patients).Main results.The accuracy of DOTD process relied on DIR and mapped contours quality. Most DIR-generated contours (99.6%) were clinically acceptable. DICE correlated with depreciation of DIR-based region of interest mapping process. The ATS-BON plan difference was found negligible (<1%). The duodenum and large bowel exhibited highest variations, 24% and 39% from fractional values, for 5-fraction liver and pancreas. For liver 1-fraction, a 62% variation was observed for duodenum.Significance.The DOTD methodology provides an automated approach to quantify 3D dosimetric differences between online plans and their delivery. This analysis offers promise as a valuable tool for plan quality assessment and decision-making in the verification stage of the online workflow.

Prognosing post-treatment outcomes of head and neck cancer using structured data and machine learning: A systematic review.

BACKGROUND: This systematic review aimed to evaluate the performance of machine learning (ML) models in predicting post-treatment survival and disease progression outcomes, including recurrence and metastasis, in head and neck cancer (HNC) using clinicopathological structured data. METHODS: A systematic search was conducted across the Medline, Scopus, Embase, Web of Science, and Google Scholar databases. The methodological characteristics and performance metrics of studies that developed and validated ML models were assessed. The risk of bias was evaluated using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). RESULTS: Out of 5,560 unique records, 34 articles were included. For survival outcome, the ML model outperformed the Cox proportional hazards model in time-to-event analyses for HNC, with a concordance index of 0.70-0.79 vs. 0.66-0.76, and for all sub-sites including oral cavity (0.73-0.89 vs. 0.69-0.77) and larynx (0.71-0.85 vs. 0.57-0.74). In binary classification analysis, the area under the receiver operating characteristics (AUROC) of ML models ranged from 0.75-0.97, with an F1-score of 0.65-0.89 for HNC; AUROC of 0.61-0.91 and F1-score of 0.58-0.86 for the oral cavity; and AUROC of 0.76-0.97 and F1-score of 0.63-0.92 for the larynx. Disease-specific survival outcomes showed higher performance than overall survival outcomes, but the performance of ML models did not differ between three- and five-year follow-up durations. For disease progression outcomes, no time-to-event metrics were reported for ML models. For binary classification of the oral cavity, the only evaluated subsite, the AUROC ranged from 0.67 to 0.97, with F1-scores between 0.53 and 0.89. CONCLUSIONS: ML models have demonstrated considerable potential in predicting post-treatment survival and disease progression, consistently outperforming traditional linear models and their derived nomograms. Future research should incorporate more comprehensive treatment features, emphasize disease progression outcomes, and establish model generalizability through external validations and the use of multicenter datasets.

A Comparison of Transoral Versus Transcervical Surgical Approaches to Retropharyngeal Lymphadenectomy: A Scoping Review.

IMPORTANCE: A gap in knowledge exists concerning the functional outcomes and complications when comparing various surgical approaches for retropharyngeal lymph node (RPLN) metastases. OBJECTIVE: To explore perioperative outcomes, functional outcomes, and complications associated in the treatment of RPLN metastases. DESIGN: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) protocol was used to conduct a scoping review of the PubMed and Scopus databases. REVIEW METHODS: We systematically searched 2 databases from inception to January 2023 for articles examining the treatment approaches and postoperative outcomes in the retropharyngeal space. We included English records about surgical approaches, complications, functional outcomes for patients >18 years old with retropharyngeal lymphadenopathy. RESULTS: One-hundred ninety-nine articles were identified, of which 17 were included in the analysis. Three studies assessed RPLN dissection in the postradiation setting. We identified limited knowledge about functional outcomes and complications following surgery for retropharyngeal lymphadenopathy. Overall, acute postoperative dysphagia was documented in 35/170 patients (20.5%). However, the assessment of dysphagia was limited, and not described in the majority of studies. The overall rate of postoperative neuropathy and hematoma were 4.1% and 4.7%, respectively. No postoperative hematomas were documented in the transcervical approach. CONCLUSION: Our findings underscore the need for further research on postoperative outcomes following RPLN dissection. We recommend further studies focusing on objective swallow assessments and long-term outcomes of either surgical approaches.

Radiology-Pathology Concordance and Prognostication of Nodal Features in pN+ Oral Cavity Cancer.

BACKGROUND AND PURPOSE: The aims of our study are to evaluate the diagnostic performance and prognostic value of radiological lymph node (LN) characteristics in pN+ oral cavity squamous carcinoma (OSCC). MATERIALS AND METHODS: pN+ OSCC treated between 2012 and 2020 were included. Preoperative imaging was reviewed by a single radiologist blinded to pathologic findings for the following nodal features: imaging-positive LN (iN+), laterality and total number, and image-identified extranodal extension (iENE). The sensitivity of iN+ for pN+ was calculated. The diagnostic performance of other nodal features was evaluated in the iN+ subgroup. The association of radiologic nodal features with overall survival (OS) was evaluated. Inter-rater kappa for radiologic nodal features was assessed in 100 randomly selected cases. RESULTS: Of 406 pN+ OSCC, 288 were iN+. The sensitivity of iN+ for pN+ was 71% overall, and improved to 89% for pN+ LN >1.5 cm. Within iN+, sensitivity/specificity for LN size (>3 cm), total LN number (>4), and ENE were 0.44/0.95, 0.57/0.84, and 0.27/0.96, respectively. Sensitivity of iENE was higher in the subset, with major (>2 mm) versus minor (≤2 mm) pENE (43% vs. 13%, p = 0.001). Reduced OS was observed in iN+ versus iN- (p = 0.006), iENE+ versus iENE- (p = 0.004), LN size >3 versus ≤3 cm (p < 0.001), and higher LN number (p < 0.001). Inter-rater kappa for iN+, laterality, total LN number, and presence of iENE were 0.71, 0.57, 0.78, and 0.69, respectively. CONCLUSION: Our study shows that despite modest sensitivity of most radiological nodal features, the specificity of image-identified nodal features is high and their prognostic values are retained in pN+ OSCC. LEVEL OF EVIDENCE: Level 3 (retrospective review comparing cases and controls) Laryngoscope, 2024.

Interobserver variation in tumor delineation of liver metastases using Magnetic Resonance Imaging.

Background and purpose: Magnetic Resonance Imaging (MRI) guided stereotactic body radiotherapy (SBRT) of liver metastases is an upcoming high-precision non-invasive treatment. Interobserver variation (IOV) in tumor delineation, however, remains a relevant uncertainty for planning target volume (PTV) margins. The aims of this study were to quantify IOV in MRI-based delineation of the gross tumor volume (GTV) of liver metastases and to detect patient-specific factors influencing IOV. Materials and methods: A total of 22 patients with liver metastases from three primary tumor origins were selected (colorectal(8), breast(6), lung(8)). Delineation guidelines and planning MRI-scans were provided to eight radiation oncologists who delineated all GTVs. All delineations were centrally peer reviewed to identify outliers not meeting the guidelines. Analyses were performed both in- and excluding outliers. IOV was quantified as the standard deviation (SD) of the perpendicular distance of each observer's delineation towards the median delineation. The correlation of IOV with shape regularity, tumor origin and volume was determined. Results: Including all delineations, average IOV was 1.6 mm (range 0.6-3.3 mm). From 160 delineations, in total fourteen single delineations were marked as outliers after peer review. After excluding outliers, the average IOV was 1.3 mm (range 0.6-2.3 mm). There was no significant correlation between IOV and tumor origin or volume. However, there was a significant correlation between IOV and regularity (Spearman's ρs = -0.66; p = 0.002). Conclusion: MRI-based IOV in tumor delineation of liver metastases was 1.3-1.6 mm, from which PTV margins for IOV can be calculated. Tumor regularity and IOV were significantly correlated, potentially allowing for patient-specific margin calculation.

Prospective manipulation of the gut microbiome with microbial ecosystem therapeutic 4 (MET4) in HPV-related locoregionally-advanced oropharyngeal cancer squamous cell carcinoma (LA-OPSCC) undergoing primary chemoradiation: ROMA2 study.

BACKGROUND: Gut microbiome modulation to boost antitumor immune responses is under investigation. METHODS: ROMA-2 evaluated the microbial ecosystem therapeutic (MET)-4 oral consortia, a mixture of cultured human stool-derived immune-responsiveness associated bacteria, given with chemoradiation (CRT) in HPV-related oropharyngeal cancer patients. Co-primary endpoints were safety and changes in stool cumulative MET-4 taxa relative abundance (RA) by 16SRNA sequencing. Stools and plasma were collected pre/post-MET-4 intervention for microbiome and metabolome analysis. RESULTS: Twenty-nine patients received ≥1 dose of MET-4 and were evaluable for safety: drug-related adverse events (AEs) occurred in 13/29 patients: all grade 1-2 except one grade 3 (diarrhea). MET-4 was discontinued early in 7/29 patients due to CRT-induced toxicity, and in 1/29 due to MET-4 AEs. Twenty patients were evaluable for ecological endpoints: there was no increase in stool MET-4 RA post-intervention but trended to increase in stage III patients (p = 0.06). MET-4 RA was higher in stage III vs I-II patients at week 4 (p = 0.03) and 2-month follow-up (p = 0.01), which correlated with changes in plasma and stool targeted metabolomics. CONCLUSIONS: ROMA-2 did not meet its primary ecologic endpoint, as no engraftment was observed in the overall cohort. Exploratory findings of engraftment in stage III patients warrants further investigation of microbiome interventions in this subgroup.

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.

Telemedicine-enabled biofeedback electropalatography rehabilitation (TEBER): A pilot study for patients treated with surgery for oral cavity carcinoma.

BACKGROUND: To address the rehabilitative barriers to frequency and precision of care, we conducted a pilot study of a biofeedback electropalatography (EPG) device paired with telemedicine for patients who underwent primary surgery +/- adjuvant radiation for oral cavity carcinoma. We hypothesized that lingual optimization followed by telemedicine-enabled biofeedback electropalatography rehabilitation (TEBER) would further improve speech and swallowing outcomes after "standard-of-care" SOC rehabilitation. METHOD: Pilot prospective 8-week (TEBER) program following 8 weeks of (SOC) rehabilitation. RESULTS: Twenty-seven patients were included and 11 completed the protocol. When examining the benefit of TEBER independent of standard of care, "range-of-liquids" improved by +0.36 [95% CI, 0.02-0.70, p = 0.05] and "range-of-solids" improved by +0.73 [95% CI, 0.12-1.34, p = 0.03]. There was a positive trend toward better oral cavity obliteration; residual volume decreased by -1.2 [95% CI, -2.45 to 0.053, p = 0.06], and "nutritional-mode" increased by +0.55 [95% CI, -0.15 to 1.24, p = 0.08]. CONCLUSION: This pilot suggests that TEBER bolsters oral rehabilitation after 8 weeks of SOC lingual range of motion.

Causes and impact of delays during the COVID-19 pandemic on head and neck cancer diagnosis.

BACKGROUND: The causes for delays during the COVID19 pandemic and their impact on head and neck cancer (HNC) diagnosis and staging are not well described. METHODS: Two cohorts were defined a priori for review and analysis-a Pre-Pandemic cohort (June 1 to December 31, 2019) and a Pandemic cohort (June 1 to December 31, 2020). Delays were categorized as COVID-19 related or not, and as clinician, patient, or policy related. RESULTS: A total of 638 HNC patients were identified including 327 in the Pre-Pandemic Cohort and 311 in the Pandemic Cohort. Patients in the Pandemic cohort had more N2-N3 category (41% vs. 33%, p = 0.03), T3-T4 category (63% vs. 50%, p = 0.002), and stage III-IV (71% vs. 58%, p < 0.001) disease. Several intervals in the diagnosis to treatment pathway were significantly longer in the pandemic cohort as compared to the Pre-Pandemic cohort. Among the pandemic cohort, 146 (47%) experienced a delay, with 112 related to the COVID-19 pandemic; 80 (71%) were clinician related, 15 (13%) were patient related, and 17 (15%) were policy related. CONCLUSIONS: Patients in the Pandemic cohort had higher stage disease at diagnosis and longer intervals along the diagnostic pathway, with COVID-19 related clinician factors being the most common cause of delay.

Transoral Robotic Surgery and Radiation Volume Deintensification in Unknown Primary Squamous Cell Carcinoma of the Neck: The Phase 2 FIND Nonrandomized Controlled Trial.

Importance: Patients with unknown primary squamous cell carcinoma (CUP) with cervical metastases typically receive comprehensive radiotherapy (RT) of the pharynx and bilateral neck. Typically, these patients receive comprehensive RT of the pharynx and bilateral neck that may produce treatment-related toxic effects. Objective: To determine whether localization of occult oropharyngeal cancers with transoral robotic surgery (TORS) combined with reduced pharyngeal and neck RT volumes provides acceptable disease control. Design, Setting, and Participants: This phase 2, single-group nonrandomized controlled trial at a single institution accrued 32 prospective participants with p16-positive CUP without a primary squamous cell carcinoma on examination and imaging from 2017 to 2019, and 24-month follow-up. The data analysis was conducted from January 2021 to June 2022. Intervention: Diagnostic- (n = 13) or therapeutic-intent (n = 9) TORS, with pharyngeal-sparing radiotherapy (PSRT) prescribed for negative margins or pT0, and unilateral neck RT (UNRT) prescribed for unilateral lymphadenopathy with lateralized primary tumor or pT0. Main Outcomes and Measures: Out-of-radiation treatment volume failure (<15% was hypothesized to be acceptable) and reports of local and regional recurrence, overall survival, toxic effects, swallowing outcomes (per the MD Anderson Dysphagia Inventory), and videofluoroscopic swallow (per Dynamic Imaging Grade of Swallowing Toxic Effects [DIGEST]) ratings. Results: The study sample comprised 22 patients (mean [SD] age, 59.1 [5.7] years; 3 [14%] females and 19 [86%] male) with CUP. Of these, 19 patients (86%) had tumor stage cN1; 2 (9%), cN2; and 1 (5%), cN3. Five patients (23%), 14 patients (64%), and 3 patients (13%) had 0, 1, or 2 primary tumors, respectively. Twenty patients received RT; of these, 9 patients (45%) underwent PSRT and 10 patients (50%), UNRT. In the diagnostic-intent group, 8 patients (62%) and 5 patients (38%) underwent RT and RT-concurrent chemotherapy, respectively. In the therapeutic-intent group, 6 patients (67%) and 1 patient (11%) received adjuvant RT-concurrent chemotherapy, respectively; 2 patients declined RT. Two-year out-of-radiation treatment volume failure, locoregional control, distant metastasis control, and overall survival were 0%, 100%, 95%, and 100%, respectively. Grade 3 or 4 surgical, acute, and late toxic effects occurred in 2 (9%), 5 (23%), and 1 (5%) patients, respectively. PSRT was associated with lower RT dose to superior constrictors (37 vs 53 Gy; mean difference, 16 Gy; 95% CI, 6.4, 24.9), smaller decline in swallowing scores during treatment (19.3 vs 39.7; mean difference, -20.4; 95% CI, -34.1 to -6.1), and fewer patients with worsening DIGEST grade on findings of videofluoroscopic swallow studies at 2 years (0% vs 60%; difference, 60%; 95% CI, 30% to 90%). Conclusions and Relevance: These findings indicate that TORS for p16-positive CUP allows RT volume deintensification with excellent outcomes and support future investigation in randomized clinical trials. Trial Registration: ClinicalTrials.gov Identifier: NCT03281499.

Prospective evaluation of patient-reported anxiety and experiences with adaptive radiation therapy on an MR-linac.

Purpose: An integrated magnetic resonance scanner and linear accelerator (MR-linac) was implemented with daily online adaptive radiation therapy (ART). This study evaluated patient-reported experiences with their overall hospital care as well as treatment in the MR-linac environment. Methods: Patients pre-screened for MR eligibility and claustrophobia were referred to simulation on a 1.5 T MR-linac. Patient-reported experience measures were captured using two validated surveys. The 15-item MR-anxiety questionnaire (MR-AQ) was administered immediately after the first treatment to rate MR-related anxiety and relaxation. The 40-item satisfaction with cancer care questionnaire rating doctors, radiation therapists, the services and care organization and their outpatient experience was administered immediately after the last treatment using five-point Likert responses. Results were analyzed using descriptive statistics. Results: 205 patients were included in this analysis. Multiple sites were treated across the pelvis and abdomen with a median treatment time per fraction of 46 and 66 min respectively. Patients rated MR-related anxiety as "not at all" (87%), "somewhat" (11%), "moderately" (1%) and "very much so" (1%). Positive satisfaction responses ranged from 78 to 100% (median 93%) across all items. All radiation therapist-specific items were rated positively as 96-100%. The five lowest rated items (range 78-85%) were related to general provision of information, coordination, and communication. Overall hospital care was rated positively at 99%. Conclusion: In this large, single-institution prospective cohort, all patients had low MR-related anxiety and completed treatment as planned despite lengthy ART treatments with the MR-linac. Patients overall were highly satisfied with their cancer care involving ART using an MR-linac.

Multimodal detection of molecular residual disease in high-risk locally advanced squamous cell carcinoma of the head and neck.

Up to 30% of patients with locally advanced head and neck squamous cell carcinoma (LA-HNSCC) relapse. Molecular residual disease (MRD) detection using multiple assays after definitive therapy has not been reported. In this study, we included patients with LA-HNSCC (stage III Human Papilloma virus (HPV)-positive, III-IVB HPV-negative) treated with curative intent. Plasma was collected pre-treatment, at 4-6 weeks (FU1) and 8-12 weeks (FU2) post-treatment. Circulating tumor DNA (ctDNA) was analyzed using a tumor-informed (RaDaR®) and a tumor-naïve (CAPP-seq) assay. HPV DNA was measured using HPV-sequencing (HPV-seq) and digital PCR (dPCR). A total of 86 plasma samples from 32 patients were analyzed; all patients with at least 1 follow-up sample. Most patients were stage III HPV-positive (50%) and received chemoradiation (78%). No patients had radiological residual disease at FU2. With a median follow-up of 25 months, there were 7 clinical relapses. ctDNA at baseline was detected in 15/17 (88%) by RaDaR and was not associated with recurrence free survival (RFS). Two patients relapsed within a year after definitive therapy and showed MRD at FU2 using RaDaR; detection of ctDNA during follow-up was associated with shorter RFS (p < 0.001). ctDNA detection by CAPP-seq pre-treatment and during follow-up was not associated with RFS (p = 0.09). HPV DNA using HPV-seq or dPCR during follow-up was associated with shorter RFS (p < 0.001). Sensitivity and specificity for MRD at FU2 using RaDaR was 40% and 100% versus 20 and 90.5% using CAPP-seq. Sensitivity and specificity for MRD during follow-up using HPV-seq was 100% and 91.7% versus 50% and 100% using dPCR. In conclusion, HPV DNA and ctDNA can be detected in LA-HNSCC before definitive therapy. The RaDaR assay but not CAPP-seq may detect MRD in patients who relapse within 1 year. HPV-seq may be more sensitive than dPCR for MRD detection.

Improving accuracy in nodal staging of oral cancer: Proposal of a new system.

BACKGROUND: Despite introduction of extranodal extension (ENE) into the AJCC 8th edition of oral cancer staging, previous criticisms persist, such as limited discrimination between sub-stages and doubtful prognostic value of contralateral nodal disease. The purpose of this study was to compare our novel nodal staging system, based on the number of positive nodes and ENE, to the AJCC staging system in surgically treated patients. METHODS: Retrospective analysis of 4710 patients with oral squamous cell carcinoma (OSCC) treated with surgery±adjuvant therapy in 8 institutions in Australia, North America and Asia. With overall survival (OS) and disease specific survival (DSS) as endpoint, the prognostic performance of AJCC 8th and 7th editions were compared using hazard consistency, hazard discrimination, likelihood difference and balance. RESULTS: Our new nodal staging system (PN) a progressive and linear increase in hazard ratio (HR) from pN0 to pN3, with good separation of Kaplan Meier curves. Using the predetermined criteria for evaluation of a staging system, our proposed staging model outperformed AJCC 8th and 7th editions in prediction of OS and DSS. CONCLUSION: PN was the lymph node staging system that provided the most accurate prediction of OS and DSS for patients in our cohort of OSCC. Additionally, it can be easily adopted, addresses the shortcomings of the existing systems and should be considered for future editions of the TNM staging system.