Hearing Outcomes in Cisplatin or Cetuximab Combined with Radiation for Patients with HPV-Associated Oropharyngeal Cancer in NRG/RTOG 1016

PURPOSE/OBJECTIVE(S)

NRG/RTOG 1016 was a noninferiority phase 3 trial comparing the efficacy of radiation with either cisplatin (RT+Cisp) or cetuximab (RT+Cetux) for patients with HPV+ oropharyngeal cancer (OPC). Perceived hearing handicap was included as a patient-reported outcome (PRO) secondary endpoint. The primary hypothesis was that perceived hearing handicap would be greater for patients receiving RT+Cisp compared to RT+Cetux.

MATERIALS/METHODS

Perceived hearing handicap was measured at baseline, end of treatment, 3, 6, and 12-months post-treatment using the Hearing Handicap Inventory for Adults Screening Version (HHIA-S), a 10-item self-assessment questionnaire designed to measure patients' reactions to their hearing loss. Total HHIA-S scores range from 0 to 40; higher total score indicates more severe perceived hearing handicap. Hearing handicap categories (none, mild/moderate, and severe) were also analyzed. Mixed ordinal logistic models were used to analyze the raw HHIA-S scores and handicap categories (2-sided alpha 0.05).

RESULTS

Participation in the PRO assessments was optional, with 368 patients participating in the hearing PRO. No significant differences in patient/tumor characteristics were found between PRO participants/non-participants. Pre-treatment (mean [SD]) HHIA-S scores were not different for RT+Cisp (3.23 [6.28]) and RT+Cetux (4.77 [8.14]) groups. Post-treatment HHIA-S scores increased for RT+Cisp, and remained stable at the later follow-up time points. RT+Cetux scores remained stable from baseline. Change score from pre- to post-treatment was higher for RT+Cisp (4.32, 95% CI = [2.57, 6.07]) than RT+Cetux (0.08, 95% CI = [-1.15, 1.31]; p < 0.001). For hearing handicap category, post-treatment RT+Cisp had a significantly higher percentage of mild/moderate and severe cases (32%) compared to RT+Cetux (20%). From pre- to post-treatment, worsening of hearing handicap category from normal to mild/moderate or severe was greater for RT+Cisp (24%) than for RT+Cetux (9%). The conditional odds of being in a higher self-perceived hearing handicap category in the RT+Cisp arm were 3.57 (95% CI [2.04, 6.25]) times that in the RT+Cetux arm. Averaging over patients, the marginal odds ratio was 2.46 (95% CI [1.65, 3.66]).

CONCLUSION

Patients receiving concurrent RT+Cisp for HPV-associated OPC have significantly higher odds of worsening self-perceived hearing handicap after treatment than with RT+Cetux. This was consistent across time through one-year post-treatment. These findings inform hearing-related outcomes for patients with HPV-associated OPC.

Acute and Late Toxicities in Patients with Collagen Vascular Disease Receiving Curative-Intent Intensity-Modulated Radiotherapy to the Head and Neck Region

PURPOSE/OBJECTIVE(S)

Historically, collagen vascular disease (CVD) was considered at least a relative contraindication to radiotherapy (RT). However, more recent meta-analyses suggest that for patients with certain CVDs such as rheumatoid arthritis (RA), there may not be an increased risk for severe toxicities, while for patients with CVDs such as systemic lupus erythematosus (SLE), dermatomyositis (DM) and scleroderma, there may be as high as a 2- to 4-fold risk for severe toxicities compared to patients without CVD. There are also data to suggest that patients with head and neck cancer (HNC) and comorbid CVD are at especially high risk of severe toxicities from RT. This study evaluated the hypothesis that among patients with HNC treated with curative-intent intensity-modulated radiation therapy (IMRT), patients with SLE or DM were more likely to have had late grade ≥3 toxicity rates compared to patients with other CVDs.

MATERIALS/METHODS

A total of 23 patients who had HNC with comorbid CVD and received IMRT between 2005-2022 were included. Acute (≤90 days after completion of RT) and late (>90 days) toxicities were retrospectively classified using CTCAE v5.0. Toxicity rates were compared across CVD groups using Chi-squared tests.

RESULTS

Median follow-up was 56.3 months. The most common CVDs were RA (9 patients, 39%), SLE (4 patients, 17%), and DM (4 patients, 17%). Median total RT dose was 66 Gy (range: 48-70 Gy), in 1.8-2.4 Gy fractions. Nine (39%) patients received concurrent chemotherapy. 14 (61%) patients had mucosal squamous cell carcinoma (SCC), 3 (13%) had cutaneous SCC, 2 (9%) had nasal cavity/paranasal sinus tumors, 2 (9%) had salivary gland tumors, 1 (4%) had cutaneous melanoma, and 1 (4%) had mucosal melanoma. Eight (35%) patients experienced acute grade ≥3 toxicities, and 3 (13%) patients experienced late grade ≥3 toxicities (Table 1). No patients had grade≥4 toxicities. Patients with SLE or DM did not have significantly higher risk of late grade ≥3 toxicities compared to those with other CVDs (25% vs. 7%, p = 0.21).

CONCLUSION

In this small sample size of patients with HNC and comorbid CVD, definitive or post-operative IMRT was associated with approximately 35% acute and 15% late severe toxicity rates. While SLE/DM were associated with >3-fold late grade ≥3 toxicities, this association needs to be confirmed with larger data sets.

Quantifying the Dosimetric Impact of Tissue Hounsfield Unit Assignment in Deep Learning-based Synthetic CT Images For MRI-Only Radiation Therapy of The Head and Neck

PURPOSE/OBJECTIVE(S)

MRI-only simulation for head and neck (HN) radiotherapy (RT) could allow for single-image modality planning with excellent soft tissue contrast. In the MRI-only simulation workflow, synthetic CTs (sCTs) are generated from MRI to provide electron density information for dose calculation. Bone/air regions produce little MRI signal which could lead to electron density misclassification in sCTs. Establishing the dosimetric impact of this error could inform quality assurance (QA) procedures using MRI-only RT planning. In this study we quantify differences in Hounsfield Unit (HU) values between paired CT/ sCTs of HN cancer patients and investigate the dosimetric impact on clinical treatment plans.

MATERIALS/METHODS

Fourteen patients with head and neck cancer undergoing same-day CT and 3T MRI simulation were retrospectively identified. MRIs were deformed to the CT using multimodal deformable image registration. SCTs were generated from T1w DIXON MRI using a commercially available deep learning-based generator (MRIplanner, Spectronics). Tissue voxel assignment was quantified by creating a CT-derived HU threshold contour. CT/sCT HU differences for anatomical/target contours and tissue classification regions including air (<-250HU), adipose tissue (-250HU to -51HU), soft tissue (-50HU to 199HU), spongy (200HU to 499HU) and cortical bone (> 500HU) were quantified. T-test was used to determine if sCT/CT HU differences were significant. The frequency of structures that had a HU difference >70HU (the CT window-width setting for intra-cranial structures) was computed to establish structure classification accuracy. Clinical IMRT treatment plans created on CTs were retrospectively recalculated on sCT images using compared using the gamma metric.

RESULTS

The mean ratio of sCT HUs relative to CT for air, adipose tissue, soft tissue, spongy and cortical bone were 1.7±0.3, 1.1±0.1, 1.0±0.1, 0.9±0.1 and 0.8±0.1 (value of 1 indicates perfect agreement). T-tests (significance set at t = 0.05) identified differences in HU values for air, spongy and cortical bone in sCT images compared to CT. The structures with sCT/CT HU differences > 70HU were the L/R cochlea and mandible, occurring in >78% of the tested cohort. These structures contain dense bone/air interfaces. Plans recalculated on sCTs yielded global/local gamma pass rates of 98.7%±1.2% (3mm,3%) and 95.5%±2.5% (1mm,1%). Mean differences in D95, D50, D10 and D2 dose volume histogram (DVH) metrics for organ-at-risk (OAR) and planning tumor volumes (PTV) were 0.8%±1.5% and 2.1% ± 1.2% respectively.

CONCLUSION

In this cohort, HU differences in sCTs were observed but did not translate into a reduction in gamma pass rates and OAR/PTV DVH metrics. The acquisition of additional training data such as ultrashort echo time MRI could improve bone/air contrast and reduce bone/air sCT misclassifications. Further studies will establish the variation in sCT dosimetric accuracy using a larger retrospective cohort to inform QA limits on clinical sCT usage.

Toxicity and Dosimetric Analysis of Reirradiation of Head and Neck Cancers with High Dose Rate Brachytherapy

PURPOSE/OBJECTIVE(S)

Reirradiation (reRT) of recurrent or second primary head and neck cancers (HNC) after prior curative-intent external beam radiotherapy (EBRT) has historically achieved local control (LC) rates of 40-50% and been associated with high grade toxicity rates estimated at 25-50%. This study evaluated the hypothesis that patients with small reRT target volumes could be selected for high dose rate brachytherapy (HDR-BT) reRT and achieve similar LC without excess toxicity.

MATERIALS/METHODS

Included were all patients with HNC squamous cell carcinoma treated with HDR-BT after having previously received curative-intent EBRT for primary HNC from 2000-2021. Patients were selected by a multidisciplinary tumor board to be appropriate candidates for HDR-BT reRT without EBRT generally for definitive or adjuvant treatment of small primary tumors without neck nodal metastases. Univariate analysis was performed using the logistic regression model. Survival outcomes were estimated with the Kaplan Meier method.

RESULTS

Twenty-three patients were evaluated. Median follow up time was 19mo. Median age at time of HDR-BT was 64 years. Thirteen patients (57%) were treated for recurrent HNC, of which 7 were in the oral cavity (OC) and 6 were the oropharynx (OPX). Ten patients (43%) were treated for a second primary HNC, of which 5 were in the OC and 5 were in the OPX. Median time from completion of EBRT to HDR-BT was 41 (IQR 14-73) mo. Within their reRT course, 11 patients (48%) were treated with HDR-BT after resection, 9 patients (39%) received concurrent hyperthermia, and 7 patients (30%) received chemotherapy. HDR-BT regimens included 600cGy x5 (N = 11), 600cGy x6 (N = 6), 450cGy x8 (N = 1), 1500cGy x1 (N = 1),1000cGy x1 (N = 1), 500cGy x8 (N = 1), and 700cGy x5 (N = 1). One patient who was treated with two implants received 450cGy x 3 followed by 475cGy x5. A median of 5 brachytherapy catheters were used. Actuarial 2-year LC and overall survival rate was 68% and 62%, respectively. Of the 17 HDR-BT reRT plans available for review, median (IQR) target volume was 15.8 (10.6-34.9) cc. Median (IQR) target V100% was 90.6 (89.4-90.0)%, V150% was 50.5 (49.7-54.4)%, and V200% was 25.4 (23.8-29.0)%. Median (IQR) target D90% was 30.1 (29.8-35.5) Gy, and median D1cc was 116.4 (100.5-171.4) Gy. The mandible dose [median (IQR)] was D2cc:15.1(9.48-18.9) Gy; D1cc:16.9(11.1-21.3) Gy; and D1%:18.8(13.4-22.7) Gy. Nine of the 23 patients (39%) experienced ≥G3 toxicity including fistula, soft tissue necrosis, osteoradionecrosis, ulcer, hemorrhage, and dysphagia requiring a chronic feeding tube. Target D90% was associated with ≥G3 toxicity (p = 0.045). For D90% greater than the median of 30Gy, 45% ≥G3 toxicity was observed.

CONCLUSION

This study suggests that HDR-BT for reRT of small recurrent or second primary HNC can provide similar LC without excess high-grade toxicities as compared to historical outcomes with EBRT reRT. Delivery of equivalent doses higher than 30Gy in 5 fractions should be approached with caution.

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.

The KRAS-Variant and Cetuximab in HPV-Positive Oropharyngeal Cancer in NRG/RTOG 1016

PURPOSE/OBJECTIVE(S)

NRG/RTOG 1016 was a non-inferiority phase III trial comparing radiation with cisplatin versus cetuximab monotherapy for patients with HPV-positive oropharyngeal squamous cell carcinoma (SCC). The trial did not meet the non-inferiority criteria for overall survival (OS) and had significantly worse progression-free survival (PFS) and locoregional failure (LRF) in patients treated with cetuximab. Based on prior evidence that HNSCC patients with a germ-line mutation in KRAS (the KRAS-variant) had a positive response to radiation with cisplatin plus cetuximab without increased toxicity, samples from RTOG 1016 were used to test the protocol-specified hypothesis that KRAS-variant patients will have better outcomes when receiving IMRT + cetuximab monotherapy compared to IMRT + cisplatin.

MATERIALS/METHODS

The KRAS-variant was tested in 562 samples at MiraDx, a CLIA-certified laboratory. OS, PFS, LRF, and distant metastases (DM) were as defined per the RTOG 1016 protocol, and hazard ratios (HRs) were estimated by (cause-specific) Cox models. Negative binomial regression was used to model the number of treatment-related acute and late (≤ and > 180 days from end of treatment, respectively) grade 3-5 adverse events. To assess the predictive role of the KRAS-variant, all models included KRAS, assigned treatment, and their interaction, with the interaction tested at two-sided 0.05. HRs and toxicity ratios are expressed as IMRT + cetuximab / IMRT + cisplatin.

RESULTS

The prevalence of the KRAS-variant was 16% with similar patient and tumor characteristics and well-balanced treatment arms for variant and non-variant patients. Median follow-up was 8.6 years. There was no significant interaction between KRAS and treatment for OS (p = 0.99), PFS (p = 0.56), LRF (p = 0.09), or DM (p = 0.19) (Table 1). In KRAS-variant patients the mean acute and late toxicity ratios were 0.53 (95% CI 0.36, 0.80) and 1.62 (95% CI 0.57, 4.62). In non-variant patients, the mean acute and late toxicity ratios were 0.80 (95% CI 0.67, 0.95) and 0.55 (95% CI 0.35, 0.87), respectively. The interaction of KRAS and treatment was not significant for acute (p = 0.07) or late toxicity (p = 0.07).

CONCLUSION

While this study does not directly refute prior evidence that KRAS-variant patients benefit from radiation + cisplatin and cetuximab, this study does not support the hypothesis that the KRAS-variant is a predictive biomarker of improved outcome in HPV+ oropharyngeal SCC patients treated with IMRT + cetuximab alone, and suggests that for KRAS-variant patients, potential benefits in LRF and acute toxicity with cetuximab may be offset by worse DM and worse late toxicity.

Submandibular Gland Transfer: A Potential Imaging Pitfall

BACKGROUND AND PURPOSE

The Seikaly and Jha submandibular gland transfer surgery is performed to facilitate gland shielding during radiation therapy for head and neck tumors to circumvent radiation-induced xerostomia. It results in an asymmetric postsurgical appearance of the submandibular and submental spaces. Our purpose was to characterize the morphologic and enhancement characteristics of the transferred submandibular gland and identify potential pitfalls in postoperative radiologic interpretation.

MATERIALS AND METHODS

This retrospective study identified patients with head and neck cancer who had undergone the submandibular gland transfer procedure at our institution. Chart reviews were performed to identify relevant oncologic histories and therapies. CT and MR neck imaging was reviewed to characterize morphologic and enhancement characteristics of the pre- and postoperative submandibular glands, as well as interpretive accuracy.

RESULTS

Eleven patients with oropharyngeal and nasopharyngeal squamous cell carcinomas who underwent submandibular gland transfer were identified. The transferred glands were significantly lengthened in the anteroposterior dimension compared with contralateral glands (P < .001) and displaced anteriorly and inferiorly within the submandibular and submental spaces. Enhancement patterns of the transferred submandibular glands varied, depending on the time of imaging relative to the operation and radiation therapy. Submandibular gland transfer was acknowledged in the postoperative report in 7/11 cases. Errors in interpretation were present in 2/11 reports.

CONCLUSIONS

After the submandibular gland transfer procedure, the submandibular and submental spaces lose their symmetric appearances as the transferred submandibular glands become lengthened and located more anteriorly and inferiorly, with variable enhancement characteristics. Familiarity with the postsurgical appearance of the transferred submandibular glands is key to accurate imaging interpretation.

Impact of Neuroradiology-Based Peer Review on Head and Neck Radiotherapy Target Delineation

BACKGROUND AND PURPOSE

While standard guidelines assist in target delineation for head and neck radiation therapy planning, the complex anatomy, varying patterns of spread, unusual or advanced presentations, and high risk of treatment-related toxicities produce continuous interpretive challenges. In 2007, we instituted weekly treatment planning quality assurance rounds as a joint enterprise of head and neck radiation oncology and neuroradiology. Here we describe its impact on head and neck radiation therapy target delineation.

MATERIALS AND METHODS

For 7 months, treatment planning quality assurance included 80 cases of definitive (48%) or postoperative (52%) head and neck radiation therapy. The planning CT and associated target volumes were reviewed in comparison with diagnostic imaging studies. Alterations were catalogued.

RESULTS

Of the 80 cases, 44 (55%) were altered, and of these, 61% had clinically significant changes resulting in exclusion or inclusion of a distinct area or structure. Reasons for alteration included the following: gross or extant tumor, 26/44 (59%); elective or postoperative coverage, 25/44 (57%); lymph nodes, 13/44 (30%); bone, 7/44 (16%); skull base, 7/44 (16%); normal organs, 5/44 (11%); perineural, 3/44 (7%); distant metastasis, 2/44 (5%); and eye, 1/44 (2%). Gross tumor changes ranged from 0.5% to 133.64%, with a median change in volume of 5.95 mm³ (7.86%). Volumes were more likely to be increased (73%) than decreased (27%).

CONCLUSIONS

A collaborative approach to head and neck treatment planning quality assurance has an impact. Cases likely to have challenging patterns of infiltrative, intracranial, nodal, orbital, or perineural spread warrant intensive imaging-based review in collaboration with a diagnostic neuroradiologist.

Induction Hedgehog pathway inhibition followed by combined-modality radiotherapy for basal cell carcinoma

Basal cell carcinoma (BCC), the most common cancer in the U.S.A., is treated primarily with local excision. In some cases, lesion size, location or extent prevent complete resection. Locally advanced BCC responds to systemic therapy with the Hedgehog pathway inhibitor vismodegib, but withdrawal of treatment may result in disease relapse. Here we present a case of locally advanced auricular BCC treated with induction vismodegib and radiation, resulting in durable local control and an acceptable level of acute toxicity.

Prognostic significance of hyoid bone invasion in advanced base of tongue carcinoma treated by chemoradiation

OBJECTIVES

To examine the prognostic influence of hyoid bone invasion in advanced base of tongue squamous cell carcinoma treated with chemoradiation.

METHODS

We retrospectively reviewed pre-treatment imaging (CT/MRI) for the presence or absence of hyoid bone invasion in patients with advanced (clinical T3 or T4a stage) base of tongue squamous cell carcinoma treated with chemoradiation from January 2001 to January 2011. We compared patients with hyoid bone invasion to those without based on the following metrics: 1-, 2- and 5-year locoregional recurrence-free survival, disease-free survival, disease-specific survival and overall survival.

RESULTS

Eleven of thirty-seven patients had hyoid invasion present on pre-treatment imaging. Average follow-up was 45 months. Patients with hyoid bone invasion were found to have lower percentages in all survival metrics measured compared to patients without, respectively, with statistical significance achieved in the following: 2-year locoregional recurrence-free survival: 36.4% versus 86.4% (P = 0.006), 5-year locoregional recurrence-free survival: 12.5% versus 63.6% (P = 0.05), 2-year disease-free survival: 36.4% versus 77.3% (P = 0.05), 5-year disease-free survival: 12.5% versus 63.3% (P = 0.05) and the Kaplan-Meier curve for locoregional recurrence-free survival (P = 0.0075).

CONCLUSIONS

Hyoid bone invasion by base of tongue squamous cell carcinoma may indicate a poorer prognosis despite treatment. Hyoid bone invasion may be a possible indication for intensification of treatment and/or may indicate a necessity for increasing the degree of post-treatment surveillance monitoring and imaging.

Oropharyngeal carcinoma arising after methotrexate and etanercept therapy for rheumatoid arthritis

Etanercept is an anti-tumor necrosis factor α receptor agent used to treat inflammatory conditions. Previous reports described rapid development of skin squamous cell carcinoma (SCC) after etanercept use. This report describes a novel case of oropharyngeal SCC associated with the use of etanercept. A 45-year-old man with rheumatoid arthritis developed oropharyngeal pain within 2 months after the start of etanercept therapy and was diagnosed with tonsillar carcinoma. This patient had other exposures that increase the risk of oropharyngeal cancer, such as tobacco and alcohol use. However, owing to the timing of onset of his initial symptoms, etanercept should be considered as a possible factor in the etiology or progression of his tumor, especially in the context of reported skin SCC after etanercept therapy in patients at risk for SCC. Clinicians should be alert to signs of malignancy in patients on etanercept, particularly those at high risk for skin or head and neck cancers.

Sonographic examination of the neck after definitive radiotherapy for node-positive oropharyngeal cancer

BACKGROUND AND PURPOSE

Radiographic determination of viable disease in cervical adenopathy following RT for head and neck cancer can be challenging. The purpose of this study was to evaluate the utility of US, with or without FNA, in regard to the postradiotherapy effects on documented metastatic adenopathy in patients with oropharyngeal cancer.

MATERIALS AND METHODS

This study included 133 patients with node-positive oropharyngeal cancer who were irradiated from 1998 to 2004. Sonographic evaluation was performed within 6 months of completion of radiation. Posttreatment US results were compared with pretreatment CT images and were recorded as the following: progression, suspicious, indeterminate, posttreatment change, or regression (positive) versus nonsuspicious or benign (negative). FNAC was classified as nondiagnostic, negative, indeterminate, or positive. Results of US and US-guided FNAC were correlated with findings at neck dissection and disease outcome.

RESULTS

Of 203 sonographic examinations, 90% were technically feasible and yielded a nonequivocal imaging diagnosis. Of 87 US-guided FNAs, 71% yielded a nonequivocal tissue diagnosis. The PPV and NPV of initial posttreatment US were 11% and 97%. Sensitivity and specificity were 92% and 28%. The PPV and NPV of US-guided FNA were 33% and 95%, and the sensitivity and specificity were 75% and 74%. On serial sonographic surveillance, of 33 patients with nonsuspicious findings, only 1 (3%) had neck recurrence. Of 22 patients with questionable findings on CT and negative findings on US, none had a neck recurrence.

CONCLUSIONS

In experienced hands, serial US is an inexpensive noninvasive reassuring follow-up strategy after definitive head and neck RT, even when CT findings are equivocal.