Advances in Radiotherapy for Head and Neck Cancer

Advanced osteoradionecrosis of the maxilla: a 15-year, single-institution experience of surgical management

BACKGROUND

Osteoradionecrosis (ORN) of the maxilla is a rare disease. In contrast with a mandibular predominance, maxillary ORN has not been widely reported.

OBJECTIVE

To review clinical features, surgical treatments, and results of maxillary ORN and offer recommendations for surgical decision-making.

MATERIAL AND METHODS

We retrospectively reviewed medical records of maxillary ORN at our hospital between 2002 and 2017. Clinical data were collected, including age, sex, primary tumor characteristics, radiotherapy dose, clinical findings of maxillary ORN, and treatment outcomes. Descriptive statistics and multiple factors were analyzed.

RESULTS

Twenty-four patients were included for analysis. The primary symptoms of maxillary ORN were pain, trismus, pus, bone exposure, and skin fistula. Twenty (83.3%) patients were completely cured after single-operation. Thirteen patients underwent sequestrectomy, and the cure rate was 76.9% (10/13). Eleven patients received segmental osteotomy and flap reconstruction, with the cure rate of 90.9% (10/11). There was no significant statistical difference in the cure rate between these two groups (p = .596).

CONCLUSIONS AND SIGNIFICANCE

Compared with mandibular ORN, the surgical effect of maxillary lesions is better and the choice of operation methods can be relatively conservative. Both sequestrectomy and segmental osteotomy with flap reconstruction can achieve good results in appropriate conditions.

Toxicities Caused by Head and Neck Cancer Treatments and Their Influence on the Development of Malnutrition: Review of the Literature

Malnutrition poses a significant problem for oncology patients, resulting in fatalities within this population. Patients with head and neck cancer (HNC) are at high risk, with up to 90% developing malnutrition. Common treatments used for HNC can often lead to adverse side effects, including oral health conditions, gastrointestinal upsets, and several metabolic changes. Consequently, treatments can cause inadequate nutritional intake, resulting in a reduction in energy consumption, and alterations in energy utilization, contributing to the development of malnutrition. Furthermore, the presence of these treatment toxicities, and the related malnutrition can lead to reduced quality of life, weight loss, and psychological distress. There are interventions available (nutritional, medicinal, and physical therapies) that have demonstrated potential effectiveness in reducing the severity of symptomatic toxicities, reducing the risk of malnutrition, and improving survival outcomes of patients with HNC. Based on the findings of this review, there is an urgent need for the implementation or continuation of multi-disciplinary strategies, as well as updated and improved guidelines to assist in the prevention and treatment of malnutrition caused by treatment-related toxicities in patients with HNC.

Development of a Tongue Immobilization Device Using a 3D Printer for Intensity Modulated Radiation Therapy of Nasopharyngeal Cancer Patients

Purpose

This study aimed to reduce radiation doses to the tongue, a patient-specific semi-customized tongue immobilization device (SCTID) was developed using a 3D printer for helical tomotherapy (HT) of nasopharyngeal cancer (NPCa). Dosimetric characteristics and setup stability of the SCTID were compared with those of a standard mouthpiece (SMP).

Materials and Methods

For displacement and robust immobilization of the tongue, the SCTID consists of four parts: upper and lower tooth stoppers, tongue guider, tongue-tip position guide bar, and connectors. With the SCTID and SMP, two sets of planning computed tomography and HT plans were obtained for 10 NPCa patients. Dosimetric and geometric characteristics were compared. Position reproducibility of the tongue with SCTID was evaluated by comparing with planned dose and adaptive accumulated dose of the tongue and base of the tongue based on daily setup mega-voltage computed tomography.

Results

Using the SCTID, the tongue was effectively displaced from the planning target volume compared to the SMP. The median mucosa of the tongue (M-tongue) dose was significantly reduced (20.7 Gy vs. 27.8 Gy). The volumes of the M-tongue receiving a dose of 15 Gy, 30 Gy, and 45 Gy and the volumes of the mucosa of oral cavity and oropharynx (M-OC/OP) receiving a dose of 45 Gy and 60 Gy were significantly lower than using the SMP. No significant differences was observed between the planned dose and the accumulated adaptive dose in any dosimetric characteristics of the tongue and base of tongue.

Conclusion

SCTID can not only reduce the dose to the M-tongue and M-OC/OP dramatically, when compared to SMP, but also provide excellent reproducibility and easy visual verification.

Randomized Clinical Trial on Reduction of Radiotherapy Dose to the Elective Neck in Head and Neck Squamous Cell Carcinoma: Results on the Quality of Life

PURPOSE

A randomized trial was initiated to investigate whether a reduction of the dose to the elective nodal sites would result in less toxicity and improvement in Quality of Life (QoL) without compromising tumor control. This paper aimed to compare QoL in both treatment arms.

METHODS

Two-hundred head and neck cancer patients treated with radiotherapy (RT) or chemo-RT were randomized (all stages, mean age: 60 years, M/F: 82%/18%). The elective nodal volumes of patients randomized in the experimental arm were treated up to a 40 Gy equivalent dose. In the standard arm, the elective nodal volumes were treated up to a 50 Gy equivalent dose. The QoL data were collected using The European Organization for Research and Treatment of Cancer (EORTC) core questionnaire QLQ-C30 and the EORTC Head and Neck Cancer module (H&N35).

RESULTS

A trend toward less decline in QoL during treatment was observed in the 40 Gy arm compared to the 50 Gy arm. Statistically significant differences for global health status, physical functioning, emotional functioning, speech problems, and trouble with social eating in favor of the 40 Gy arm were observed. A clinically relevant better outcome in the 40 Gy arm was found for physical functioning at the end of therapy.

CONCLUSION

QoL during RT for head and neck cancer tends to be less impaired in the 40 Gy arm. However, reducing the dose only on the elective neck does not result in clinically relevant improvement of QoL. Therefore, additional treatment strategies must be examined to further improve the QoL of HNSCC patients.

Imaging for Target Delineation in Head and Neck Cancer Radiotherapy

The definition of tumor involved volumes in patients with head and neck cancer poses great challenges with the increasing use of highly conformal radiotherapy techniques eg, volumetric modulated arc therapy and intensity modulated proton therapy. The risk of underdosing the tumor might increase unless great care is taken in the process. The information gained from imaging is increasing with both PET and MRI becoming readily available for the definition of targets. The information gained from these techniques is indeed multidimensional as one often acquire data on eg, metabolism, diffusion, and hypoxia together with anatomical and structural information. Nevertheless, much work remains to fully exploit the available information on a patient-specific level. Multimodality target definition in radiotherapy is a chain of processes that must be individually scrutinized, optimized and quality assured. Any uncertainties or errors in image acquisition, reconstruction, interpretation, and delineation are systematic errors and hence will potentially have a detrimental effect on the entire radiotherapy treatment and hence; the chance of cure or the risk of unnecessary side effects. Common guidelines and procedures create a common minimum standard and ground for evaluation and development. In Denmark, the treatment of head and neck cancer is organized within the multidisciplinary Danish Head and Neck Cancer Group (DAHANCA). The radiotherapy quality assurance group of DAHANCA organized a workshop in January 2020 with participants from oncology, radiology, and nuclear medicine from all centers in Denmark, treating patients with head and neck cancer. The participants agreed on a national guideline on imaging for target delineation in head and neck cancer radiotherapy, which has been approved by the DAHANCA group. The guidelines are available in the Supplementary. The use of multimodality imaging is being recommended for the planning of all radical treatments with a macroscopic tumor. 2-[¹⁸F]FDG-PET/CT should be available, preferable in the treatment position. The recommended MRI sequences are T1, T2 with and without fat suppression, and T1 with contrast enhancement, preferable in the treatment position. The interpretation of clinical information, including thorough physical examination as well as imaging, should be done in a multidisciplinary setting with an oncologist, radiologist, and nuclear medicine specialist.

Salivary Gland Hypofunction and Xerostomia in Head and Neck Radiation Patients

BACKGROUND

The most manifest long-term consequences of radiation therapy in the head and neck cancer patient are salivary gland hypofunction and a sensation of oral dryness (xerostomia).

METHODS

This critical review addresses the consequences of radiation injury to salivary gland tissue, the clinical management of salivary gland hypofunction and xerostomia, and current and potential strategies to prevent or reduce radiation injury to salivary gland tissue or restore the function of radiation-injured salivary gland tissue.

RESULTS

Salivary gland hypofunction and xerostomia have severe implications for oral functioning, maintenance of oral and general health, and quality of life. Significant progress has been made to spare salivary gland function chiefly due to advances in radiation techniques. Other strategies have also been developed, e.g., radioprotectors, identification and preservation/expansion of salivary stem cells by stimulation with cholinergic muscarinic agonists, and application of new lubricating or stimulatory agents, surgical transfer of submandibular glands, and acupuncture.

CONCLUSION

Many advances to manage salivary gland hypofunction and xerostomia induced by radiation therapy still only offer partial protection since they are often of short duration, lack the protective effects of saliva, or potentially have significant adverse effects. Intensity-modulated radiation therapy (IMRT), and its next step, proton therapy, have the greatest potential as a management strategy for permanently preserving salivary gland function in head and neck cancer patients.Presently, gene transfer to supplement fluid formation and stem cell transfer to increase the regenerative potential in radiation-damaged salivary glands are promising approaches for regaining function and/or regeneration of radiation-damaged salivary gland tissue.

In vivo and in vitro radiotherapy increased dentin enzymatic activity

OBJECTIVES

The present study investigated the effects of in vitro and in-vivo radiotherapy on endogenous enzymatic activity in dentin using gelatin zymography and in-situ zymography.

METHODS

Gelatin zymographic assays were performed on protein extracts obtained from dentin powder of sound non-irradiated (NRT), in vitro irradiated (VTRT) and in vivo irradiated (VIRT) human teeth. Their proteolytic activities were quantified using band densitometric evaluation. For in-situ zymography, dentin specimens from NRT, VIRT and VTRT were covered with fluorescein-conjugated gelatin and examined with confocal laser-scanning microscopy. Fluorescence intensity emitted by the hydrolyzed fluorescein-conjugated gelatin was quantified and statistically analyzed. In-situ zymography data were statistically analyzed using Kruskal-Wallis ANOVA and Dunn's multiple comparison procedures (α = 0.05).

RESULTS

No difference between in vitro and in vivo radiotherapy treatment was found. Both VTRT and VIRT groups showed increase in MMP-9 expression when compared to NRT group. Significant increases (p < 0.05) in gelatinolytic activity (26 % for VTRT; 55 % for VIRT) were observed when compared to the NRT group.

CONCLUSION

Radiotherapy increase endogenous enzymatic activity in non-restored dentin.

Cone-beam CT-derived relative stopping power map generation via deep learning for proton radiotherapy

PURPOSE

In intensity-modulated proton therapy (IMPT), protons are used to deliver highly conformal dose distributions, targeting tumors, and sparing organs-at-risk. However, due to uncertainties in both patient setup and relative stopping power (RSP) calculation, margins are added to the treatment volume during treatment planning, leading to higher doses to normal tissues. Cone-beam computed tomography (CBCT) images are taken daily before treatment; however, the poor image quality of CBCT limits the use of these images for online dose calculation. In this work, we use a deep-learning-based method to predict RSP maps from daily CBCT images, allowing for online dose calculation in a step toward adaptive radiation therapy.

METHODS

Twenty-three head-and-neck cancer patients were simulated using a Siemens TwinBeam dual-energy CT (DECT) scanner. Mixed-energy scans (equivalent to a 120 kVp single-energy CT scan) were converted to RSP maps for treatment planning. Cone-beam computed tomography images were taken on the first day of treatment, and the planning RSP maps were registered to these images. A deep learning network based on a cycle-GAN architecture, relying on a compound loss function designed for structural and contrast preservation, was then trained to create an RSP map from a CBCT image. Leave-one-out and holdout cross validations were used for evaluation, and mean absolute error (MAE), mean error (ME), peak signal-to-noise ratio (PSNR), and structural similarity (SSIM) were used to quantify the differences between the CT-based and CBCT-based RSP maps. The proposed method was compared to a deformable image registration-based method which was taken as the ground truth and two other deep learning methods. For one patient who underwent resimulation, the new planning RSP maps and CBCT images were used for further evaluation and validation.

RESULTS

The CBCT-based RSP generation method was evaluated on 23 head-and-neck cancer patients. From leave-one-out testing, the MAE between CT-based and CBCT-based RSP was 0.06 ± 0.01 and the ME was -0.01 ± 0.01. The proposed method statistically outperformed the comparison DL methods in terms of MAE and ME when compared to the planning CT. In terms of dose comparison, the mean gamma passing rate at 3%/3 mm was 94% when three-dimensional (3D) gamma index was calculated per plan and 96% when gamma index was calculated per field.

CONCLUSIONS

The proposed method provides sufficiently accurate RSP map generation from CBCT images, allowing for evaluation of daily dose based on CBCT and possibly allowing for CBCT-guided adaptive treatment planning for IMPT.

Should oral foci of infection be removed before the onset of radiotherapy or chemotherapy?

Pretreatment dental screening aims to locate and eliminate oral foci of infection in order to eliminate local, loco-regional, or systemic complications during and after oncologic treatment. An oral focus of infection is a pathologic process in the oral cavity that does not cause major infectious problems in healthy individuals, but may lead to severe local or systemic inflammation in patients subjected to oncologic treatment. As head and neck radiotherapy patients bear a lifelong risk on oral sequelae resulting from this therapy, the effects of chemotherapy on healthy oral tissues are essentially temporary and reversible. This has a large impact on what to consider as an oral focus of infection when patients are subjected to, for example, head and neck radiotherapy for cancer or intensive chemotherapy for hematological disorders. While in patients subjected to head and neck radiotherapy oral foci of infection have to be removed before therapy that may cause problems ultimately, in patients that will receive chemotherapy such, so-called chronic, foci of infection are not in need of removal of teeth but can be treated during a remission phase. Acute foci of infection always have to be removed before or early after the onset of any oncologic treatment.

Radiation dose-painting with protons vs. photons for head-and-neck cancer

Background: Dose-painting has recently been investigated in early-phase trials in head-and-neck cancer (HNC) with the aim of improving local tumor control. At the same time proton therapy has been reported as potentially capable of decreasing toxicity. Here, we investigate whether protons could be applied in a dose-painting setting by comparing proton dose distributions with delivered photon plans from a phase-I trial of FDG-PET based dose-painting at our institution.Material and methods: Eleven oropharynx (5), hypopharynx (2) and larynx cancer (4) patients from the recently conducted phase I trial were used for comparison of proton and photon dose-painting techniques. Robust optimization (3.5%/3 mm) was used for proton plans. Plan robustness and difference in dose metrics to targets and organs at risk were evaluated.Results: The proton plans met target dose constraints, while having lower non-target dose than photon plans (body-minus-CTV, mean dose 3.9 Gy vs 7.2 Gy, p = .004). Despite the use of robust proton planning for plan max dose, photon plan max doses were more robust (p = .006). Max dose to medulla, brainstem and mandible were lower in the proton plans, while there was no significant difference in mean dose to submandibular- and parotid glands.Conclusion: Proton dose-painting for HNC seems feasible and can reduce the non-target dose overall, however not significantly to certain organs close to the target, such as the salivary glands. Max dose in proton plans had a lower robustness compared to photons, requiring caution to avoid unintended hot spots in consideration of the risk of mucosal toxicity.

Salivary microRNAs identified by small RNA sequencing as potential predictors of response to intensity-modulated radiotherapy in head and neck cancer patients

PURPOSE

Progress in radiation therapy of head and neck squamous cell carcinomas (HNSCCs) is logically linked to the development of molecular predictors that would help to enhance individually tailored treatment. MicroRNA (miRNA) expression profiles in tumors have repeatedly been tested to optimize the molecular diagnostics of HNSCC. In addition to tumor tissues, miRNAs are stably present in body fluids, including saliva, and can thus be collected non-invasively. The aim of our current study was to evaluate whether salivary miRNAs have potential as response predictors in HNSCC patients treated with intensity modulated radiation therapy (IMRT).

METHODS

In total 48 HNSCC patients treated by definitive IMRT were enrolled in our prospective study. To identify predictive salivary miRNAs, we used small RNA sequencing in 14 saliva samples of HNSCC patients and qRT-PCR validation of selected miRNA candidates in an independent set of 34 patients.

RESULTS

We found that salivary miR-15a-5p and miR-15b-5p exhibited differential levels between patients with and without complete remission (p = 0.025 and p = 0.028, respectively). Subsequent Kaplan-Meier analysis confirmed that patients with higher levels of miR-15a-5p reached a significantly longer locoregional progression-free survival (LPFS) than those with low levels (p = 0.024). Finally, multivariate Cox regression analysis revealed that miR-15a-5p may serve as an independent predictive biomarker of LPFS in HNSCC patients treated with IMRT (HR 0.104; 95% CI 0.004-0.911; p = 0.04).

CONCLUSIONS

We conclude that salivary miR-15a-5p may represent a potential biomarker for individualized treatment decision-making in HNSCC patients.

Knockdown of lncRNA BLACAT1 enhances radiosensitivity of head and neck squamous cell carcinoma cells by regulating PSEN1

OBJECTIVE

This work focused on the function role and underlying mechanism of BLACAT1 in regulating the radiosensitivity of head and neck squamous cell carcinoma (HNSCC) cells via PSEN1.

METHODS

BLACAT1 and PSEN1 expression in HNSCC tissues and cells were measured by qRT-PCR. Kaplan-Meier method and Spearman's correlation analysis determined the prognostic roles and association of BLCAT1 and PSEN1 in HNSCC. The impacts of BLACAT1 and PSEN1, alone and in combination, on radiosensitivity of HNSCC cells were separately assessed through CCK-8, colony formation, flow cytometry, western blot and γH2AX foci staining assays.

RESULTS

Our study disclosed that BLACAT1 and PSEN1 were both in association with poor prognosis and radioresistance of HNSCC cells. BLACAT1 knockdown improved the radiosensitivity of HNSCC cells by changing cellular activities containing repressed cell viability, accelerated cell apoptosis, induced cell cycle arrest, and stimulated DNA damage response. Further, we found that PSEN1 was positively correlated with BLACAT1. Rescue assays confirmed that BLACAT1 regulated the radiosensitivity of HNSCC cells by modulating PSEN1.

CONCLUSION

We revealed that BLACAT1 knockdown enhanced radioresistance of HNSCC cells via regulating PSEN1, exposing the probable target role of BLACAT1 in HNSCC.

ADVANCES IN KNOWLEDGE

This was the first time that the pivotal role of BLACAT1 was investigated in HNSCC, which provided a novel therapeutic direction for HNSCC patients.

The Changes in Pharyngeal Constrictor Muscles Related to Head and Neck Radiotherapy: A Systematic Review

It is well known that radiation damage of the pharyngeal constrictor muscles, the glottic larynx, and the supraglottic larynx may lead to dysphagia, an unwanted effect of head and neck radiotherapy. The reduction of radiotherapy-induced dysphagia might be achieved by adaptive radiotherapy. Although the number of studies concerning adaptive radiotherapy of head and neck cancer is continuously increasing, there are only a few studies concerning changes in dysphagia-related structures during radiotherapy.The goal of this review is to summarize the current knowledge about volumetric, dosimetric, and other changes of the pharyngeal constrictor muscles associated with head and neck radiotherapy. A literature search was performed in the MEDLINE database according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The conclusions of 8 studies that passed the criteria indicate a significant increase in the volume and the thickness of the pharyngeal constrictor muscles during radiotherapy. Moreover, the changes in magnetic resonance imaging signal intensity of the pharyngeal constrictor muscles correlate with the absorbed dose (typically higher than 50 Gy) and also with the grade of dysphagia. This systematic review presents 2 variables, which are suitable for estimation of radiotherapy-related pharyngeal constrictor muscles changes-magnetic resonance imaging signal intensity and the thickness. In the case of the thickness, there is no consensus in the level of the measurement-C2 vertebra, C3 vertebra, and the middle of the craniocaudal axis are used. It seems that reference to a position associated with a vertebral body could be more reproducible and beneficial for future research. Although late pharyngeal toxicity remains a challenge in head and neck cancer treatment, better knowledge of radiotherapy-related changes in the pharyngeal constrictor muscles contributes to adaptive radiotherapy development and thus improves the treatment results.

Predictive quantitative ultrasound radiomic markers associated with treatment response in head and neck cancer

Aim:

We aimed to identify quantitative ultrasound (QUS)-radiomic markers to predict radiotherapy response in metastatic lymph nodes of head and neck cancer.

Materials & methods:

Node-positive head and neck cancer patients underwent pretreatment QUS imaging of their metastatic lymph nodes. Imaging features were extracted using the QUS spectral form, and second-order texture parameters. Machine-learning classifiers were used for predictive modeling, which included a logistic regression, naive Bayes, and k-nearest neighbor classifiers.

Results:

There was a statistically significant difference in the pretreatment QUS-radiomic parameters between radiological complete responders versus partial responders (p < 0.05). The univariable model that demonstrated the greatest classification accuracy included: spectral intercept (SI)-contrast (area under the curve = 0.741). Multivariable models were also computed and showed that the SI-contrast + SI-homogeneity demonstrated an area under the curve = 0.870. The three-feature model demonstrated that the spectral slope-correlation + SI-contrast + SI-homogeneity-predicted response with accuracy of 87.5%.

Conclusion:

Multivariable QUS-radiomic features of metastatic lymph nodes can predict treatment response a priori.

In this study, quantitative ultrasound (QUS) and machine-learning classification was used to predict treatment outcomes in head and neck cancer patients. Metastatic lymph nodes in the neck were scanned using conventional frequency ultrasound (US). Quantitative data were collected from the US-radiofrequency signal a priori. Machine-learning classification models were computed using QUS features; these included the linear fit parameters of the power spectrum, and second-order texture parameters of the QUS parametric images. Treatment outcomes were measured based on radiological response. Patients were classified into binary groups: radiologic complete response (CR) or radiological partial response (PR), which was assessed 3 months following treatment. Initial results demonstrate high accuracy (%Acc = 87.5%) for predicting radiological response. The results of this study suggest that QUS can be used to predict head and neck cancer response to radiotherapy a priori.

Factors Associated With Head and Neck Cancer Hospitalization Cost and Length of Stay-A National Study

OBJECTIVES

The aim of the study was to estimate hospitalization cost, and factors associated with hospitalization costs and length of stay (LOS) of patients treated for head and neck cancer in the United States.

METHODS

Data on 71,440 weighted hospital admissions from the 2014 National Inpatient Sample with a diagnosis of head and neck cancer were examined. Multivariable linear regression models estimated factors associated with hospitalization costs, and negative binomial regression models were used to identify factors associated with hospital LOS. Factor variables included characteristics of the patient, clinical, and hospital characteristics.

RESULTS

The average hospitalization cost was US $18,371 and the average LOS was 6.6 days. LOS was significantly associated with admissions involving bacterial infection, major operating procedures, chemo procedure, and radiation procedure as well as admissions at medium or small bed size hospitals, and rural hospitals. Admissions among black patients, elective admissions, admissions involving bacterial infection, major operating procedures, chemo procedure, radiation procedure, and advance comorbidities were associated with increased hospitalization costs. In contrast, admissions at urban nonteaching or rural had increased hospitalization costs.

CONCLUSIONS

Admissions that involve higher number of comorbidities, metastasis, bacterial infection, radiation, and chemo procedures had longer hospital stay and higher cost whereas admissions are rural hospitals had shorter hospital stay and lower cost. Understanding these factors associated with increased LOS and hospitalization cost will help efforts to decrease health care cost and improve quality of care.

Analysis of skin dose distribution for the prediction of severe radiation dermatitis in head and neck squamous cell carcinoma patients treated with concurrent chemo-radiotherapy

BACKGROUND

We investigated whether the pattern of intensity-modulated radiotherapy (IMRT) dose distribution to the skin can be correlated with the development of G3/G4 radiation dermatitis (RD).

METHODS

A frequency-matched cohort analysis was perfomed on patients treated with IMRT and concurrent cisplatin or cetuximab. Risk ratios were obtained by fitting Poisson regression models.

RESULTS

The incidence of G3/G4 RD was 41.1% in 90 patients included (50% vs 36.6% in the cetuximab and cisplatin cohorts, respectively). In multivariate analysis, PS ≥ 1 and weight loss at RT completion >10 kg were the only factors that retained significance. The best dosimetric predictive accuracy was provided by 19.9 cc and 5.8 cc of skin ring 2 mm V50 and V60, respectively (AUC: 0.61 for both).

CONCLUSION

Along with clinical factors, the pattern of dose distribution to a ring structure localized 2 mm below the patient's surface may help predict the development of severe RD.

Adaptive radiotherapy for head and neck cancer reduces the requirement for rescans during treatment due to spinal cord dose

BACKGROUND

Patients treated with radiotherapy for head and neck (H&N) cancer often experience anatomical changes. The potential compromises to Planning Target Volume (PTV) coverage or Organ at Risk (OAR) sparing has prompted the use of adaptive radiotherapy (ART) for these patients. However, implementation of ART is time and resource intensive. This study seeks to define a clinical trigger for H&N re-plans based on spinal cord safety using kV Cone-Beam Computed Tomography (CBCT) verification imaging, in order to best balance clinical benefit with additional workload.

METHODS

Thirty-one H&N patients treated with Volumetric Modulated Arc Therapy (VMAT) who had a rescan CT (rCT) during treatment were included in this study. Contour volume changes between the planning CT (pCT) and rCT were determined. The original treatment plan was calculated on the pCT, CBCT prior to the rCT, pCT deformed to the anatomy of the CBCT (dCT), and rCT (considered the gold standard). The dose to 0.1 cc (D0.1cc) spinal cord was evaluated from the Dose Volume Histograms (DVHs).

RESULTS

The median dose increase to D0.1cc between the pCT and rCT was 0.7 Gy (inter-quartile range 0.2-1.9 Gy, p < 0.05). No correlation was found between contour volume changes and the spinal cord dose increase. Three patients exhibited an increase of 7.0-7.2 Gy to D0.1cc, resulting in a re-plan; these patients were correctly identified using calculations on the CBCT/dCT.

CONCLUSIONS

An adaptive re-plan can be triggered using spinal cord doses calculated on the CBCT/dCT. Implementing this trigger can reduce patient appointments and radiation dose by eliminating up to 90% of additional un-necessary CT scans, reducing the workload for radiographers, physicists, dosimetrists, and clinicians.

The changing therapeutic landscape of head and neck cancer

Head and neck cancers are a heterogeneous collection of malignancies of the upper aerodigestive tract, salivary glands and thyroid. In this Review, we primarily focus on the changing therapeutic landscape of head and neck squamous cell carcinomas (HNSCCs) that can arise in the oral cavity, oropharynx, hypopharynx and larynx. We highlight developments in surgical and non-surgical therapies (mainly involving the combination of radiotherapy and chemotherapy), outlining how these treatments are being used in the current era of widespread testing for the presence of human papillomavirus infection in patients with HNSCC. Finally, we describe the clinical trials that led to the approval of the first immunotherapeutic agents for HNSCC, and discuss the development of strategies to decrease the toxicity of different treatment modalities.

A Review of Controversial Issues in the Management of Head and Neck Cancer: A Swiss Multidisciplinary and Multi-Institutional Patterns of Care Study-Part 4 (Biomarkers)

Background: The Head and Neck Cancer Working Group of Swiss Group for Clinical Cancer Research (SAKK) has investigated the level of consensus (LOC) and discrepancy in everyday practice of diagnosis and treatment in head and neck cancer. Materials and Methods: An online survey was iteratively generated with 10 Swiss university and teaching hospitals. LOC below 50% was defined as no agreement, while higher LOC were arbitrarily categorized as low (51-74%), moderate (75-84%), and high (≥85%). Results: Any LOC was achieved in 62% of topics (n = 60). High, moderate, and low LOC were found in 18, 20, and 23%, respectively. Regarding Head and Neck Surgery, Radiation Oncology, Medical Oncology, and biomarkers, LOC was achieved in 50, 57, 83, and 43%, respectively. Conclusions: Consensus on clinical topics is rather low for surgeons and radiation oncologists. The questions discussed might highlight discrepancies, stimulate standardization of practice, and prioritize topics for future clinical research.

Organ Preservation and Late Functional Outcome in Oropharyngeal Carcinoma: Rationale of EORTC 1420, the "Best of" Trial

Dysphagia represents one of the most serious adverse events after curative-intent treatments with a tremendous impact on quality of life in patients with head and neck cancers. Novel surgical and radiation therapy techniques have been developed to better preserve swallowing function, while not negatively influencing local control and/or overall survival. This review focuses on the current literature of swallowing outcomes after curative treatment strategies. Available results from recent studies relevant to this topic are presented, demonstrating the potential role of new treatment modalities for early- and intermediate-stage oropharyngeal cancers. Based on this, we present the rationale and design of the currently active EORTC 1420 "Best of" trial, and highlight the potential of this study to help prioritizing either surgery- or radiation-based treatment modalities for the treatment of oropharyngeal cancer in the future.

Volumetric modulated arc therapy treatment planning based on virtual monochromatic images for head and neck cancer: effect of the contrast-enhanced agent on dose distribution

Virtual monochromatic images (VMIs) at a lower energy level can improve image quality but the computed tomography (CT) number of iodine contained in the contrast‐enhanced agent is dramatically increased. We assessed the effect of the use of contrast‐enhanced agent on the dose distributions in volumetric modulated arc therapy (VMAT) planning for head and neck cancer (HNC). Based on the VMIs at 40 keV (VMI_40keV), 60 keV(VMI_60keV), and 77 keV (VMI_77keV) of a tissue characterization phantom, lookup tables (LUTs) were created. VMAT plans were generated for 15 HNC patients based on contrast‐enhanced‐ (CE‐) VMIs at 40‐, 60‐, and 77 keV using the corresponding LUTs, and the doses were recalculated based on the noncontrast‐enhanced‐ (nCE‐) VMIs. For all structures, the difference in CT numbers owing to the contrast‐enhanced agent was prominent as the energy level of the VMI decreased, and the mean differences in CT number between CE‐ and nCE‐VMI was the largest for the clinical target volume (CTV) (125.3, 55.9, and 33.1 HU for VMI_40keV, VMI_60keV, and VMI_77keV, respectively). The mean difference of the dosimetric parameters (D_99%, D_50%, D_1%, D_mean, and D_0.1cc) for CTV and OARs was <1% in the treatment plans based on all VMIs. The maximum difference was observed for CTV in VMI_40keV (2.4%), VMI_60keV (1.9%), and VMI_77keV (1.5%) plans. The effect of the contrast‐enhanced agent was larger in the VMAT plans based on the VMI at a lower energy level for HNC patients. This effect is not desirable in a treatment planning procedure.

Nutritional experiences in head and neck cancer patients

OBJECTIVE

Extensive research has documented the negative nutritional impact of head neck cancer (HNC) treatment, but few studies have addressed the patients' experiences. The purpose of this study was to describe how patients with HNC experience the nutritional situation and perceive nutritional support from diagnosis to the post-treatment phase.

METHODS

Patients with HNC were recruited from a randomised pilot study. Individual interviews were conducted after radiotherapy with 10 participants aged 49 - 70 years and analysed by qualitative content analysis.

RESULTS

Undergoing surgery was experienced as a poor nutritional starting point for the upcoming radiotherapy. During radiotherapy, increasing side effects made the participants customise their meals to improve food intake. About halfway through radiotherapy, virtually no food intake was experienced and hospital admissions and initiations of tube-feeding occurred in this period. Oral nutritional supplements were recommended for all, but eventually became unbearable to ingest. When radiotherapy was finally completed, the participants felt discouraged about the persistent side effects preventing them from resume eating. The participants missed tailored information about development of side effects and involvement of a dietitian when reflecting on the treatment-period.

CONCLUSION

The comprehensive nutritional problems experienced by patients with HNC require early nutritional assessments and improved individually tailored nutritional support.

Research Frontiers in Oral Toxicities of Cancer Therapies: Osteoradionecrosis of the Jaws

The deleterious effects of head and neck radiation on bone, with osteoradionecrosis (ORN) as the major disabling side effect of head and neck cancer treatment, are difficult to prevent and hard to treat. This review focuses on the current state of the science regarding the pathobiology, clinical impact, and management of ORN. With regard to the pathobiology underlying ORN, it is not yet confirmed whether the current radiation schedules by 3-dimensional conformal radiotherapy and intensity modified radiotherapy result in an unchanged, decreased, or increased risk of developing ORN when compared with conventional radiation treatment, the main risk factor being the total radiation dose delivered on any clinically significant surface of the mandible.

With regard to the prevention of ORN, a thorough, early pre-irradiation dental assessment is still considered the first step to reduce the hazard of developing ORN post-radiotherapy, and hyperbaric oxygen (HBO) treatment reduces the risk of developing ORN in case of dental surgery in an irradiated field.

With regard to the treatment of ORN, the focus is bidirectional: elimination of the necrotic bone and improving the vascularity of the normal tissues that were included in the radiation portal. The cure rate of limited ORN by conservative therapy is approximately 50%, and the cure rate of surgical approaches when conservative therapy has failed is approximately 40%.

Whether it is effective to support conservative or surgical treatment with HBO as an adjuvant is not set. HBO treatment is shown to increase the vascularity of hard and soft tissues and has been reported to be beneficial in selected cases. However, in randomized clinical trials comparing the preventive effect of HBO on developing ORN with, eg, antibiotic coverage in patients needing dental surgery, the preventive effect of HBO was not shown to surpass that of a more conservative approach.

More recently, pharmacologic management was introduced in the treatment of ORN with success, but its efficacy has to be confirmed in randomized clinical trials. The major problem of performing well-designed randomized clinical trials in ORN is having access to large numbers of patients with well-defined, comparable cases of ORN. Because many institutions will not have large numbers of such ORN cases, national and international scientific societies must be approached to join multicenter trials. Fortunately, the interest of funding organizations and the number researchers with an interest in healthy aging is growing. Research aimed at prevention and reduction of the morbidity of cancer treatment fits well within these programs.

Radiosensitization approaches for HPV-positive and HPV-negative head and neck squamous carcinomas

Radiotherapy is one of the most used treatment approaches for head and neck squamous cell carcinoma (HNSCC). Targeted inhibition of DNA repair machinery has the potential to improve treatment response by tailoring treatment to cancer cells lacking specific DNA repair pathways. Human papillomavirus (HPV)‐negative and HPV‐positive HNSCCs respond differently to radiotherapy treatment, suggesting that different approaches of DNA repair inhibition should be employed for these HNSCC groups. Here, we searched for optimal radiosensitization approaches for HPV‐positive and HPV‐negative HNSCCs by performing a targeted CRISPR‐Cas9 screen. We found that inhibition of base excision repair resulted in a better radiotherapy response in HPV‐positive HNSCC, which is correlated with upregulation of genes involved in base excision repair. In contrast, inhibition of nonhomologous end‐joining and mismatch repair showed strong effects in both HNSCC groups. We validated the screen results by combining radiotherapy with targeted inhibition of DNA repair in several preclinical models including primary and recurrent patient‐derived HNSCC xenografts. These findings underline the importance of stratifying HNSCC patients for combination treatments.

What's new?

The combination of radiotherapy and targeted inhibition of DNA repair pathways can potentially improve therapeutic response in patients with head and neck squamous cell carcinoma (HNSCC). Here, a targeted CRISPR‐Cas9 screen was used to identify optimal radiosensitization approaches for human papillomavirus (HPV)‐positive and HPV‐negative HNSCC. Inhibition of base excision repair was associated with improved radiotherapy response in HPV‐positive HNSCC cells. By comparison, inhibition of non‐homologous end‐joining and mismatch repair was effective in both HPV‐positive and HPV‐negative cells. The screen results were validated in patient‐derived xenograft models, suggesting that stratification of HNSCC patients by HPV status may benefit therapeutic outcome.

Early clinical outcomes of helical tomotherapy/intensity-modulated proton therapy combination in nasopharynx cancer

This study aimed to evaluate the feasibility of combining helical tomotherapy (HT) and intensity‐modulated proton therapy (IMPT) in treating patients with nasopharynx cancer (NPC). From January 2016 to March 2018, 98 patients received definitive radiation therapy (RT) with concurrent chemotherapy (CCRT). Using simultaneous integrated boost and adaptive re‐plan, 3 different dose levels were prescribed: 68.4 Gy in 30 parts to gross tumor volume (GTV), 60 Gy in 30 parts to high‐risk clinical target volume (CTV), and 36 Gy in 18 parts to low‐risk CTV. In all patients, the initial 18 fractions were delivered by HT, and, after rival plan evaluation on the adaptive re‐plan, the later 12 fractions were delivered either by HT in 63 patients (64.3%, HT only) or IMPT in 35 patients (35.7%, HT/IMPT combination), respectively. Propensity‐score matching was conducted to control differences in patient characteristics. In all patients, grade ≥ 2 mucositis (69.8% vs 45.7%, P = .019) and grade ≥ 2 analgesic usage (54% vs 37.1%, P = .110) were found to be less frequent in HT/IMPT group. In matched patients, grade ≥ 2 mucositis were still less frequent numerically in HT/IMPT group (62.9% vs 45.7%, P = .150). In univariate analysis, stage IV disease and larger GTV volume were associated with increased grade ≥ 2 mucositis. There was no significant factor in multivariate analysis. With the median 14 month follow‐up, locoregional and distant failures occurred in 9 (9.2%) and 12 (12.2%) patients without difference by RT modality. In conclusion, comparable early oncologic outcomes with more favorable acute toxicity profiles were achievable by HT/IMPT combination in treating NPC patients.

Development of a semi-customized tongue displacement device using a 3D printer for head and neck IMRT

Purpose

To reduce radiation doses to the tongue, a patient-specific semi-customized tongue displacement device (SCTDD) was developed using a 3D printer (3DP) for head and neck (H&N) radiation therapy (RT). Dosimetric characteristics of the SCTDD were compared with those of a standard mouthpiece (SMP).

Materials and methods

The SCTDD consists of three parts: a mouthpiece, connector with an immobilization mask, and tongue displacer, which can displace the tongue to the contralateral side of the planning target volume. Semi-customization was enabled by changing the thickness and length of the SCTDD. The instrument was printed using a 3DP with a biocompatible material. With the SCTDD and SMP, two sets of planning computed tomography (CT) and tomotherapy plans were obtained for seven H&N cancer patients. Dosimetric and geometric characteristics were compared.

Results

Using the SCTDD, the tongue was effectively displaced from the planning target volume without significant tongue volume change compared to the SMP. The median tongue dose was significantly reduced (29.6 Gy vs. 34.3 Gy). The volumes of the tongue receiving a dose of 15 Gy, 30 Gy, 35 Gy, 45 Gy, and 60 Gy were significantly lower than using the SMP.

Conclusion

The SCTDD significantly decreased the radiation dose to the tongue compared to the SMP, which may potentially reduce RT-related tongue toxicity.

Radiation-induced sensitivity of tissue-resident mesenchymal stem cells in the head and neck region

BACKGROUND

Tissue-resident mesenchymal stem cells (MSCs) possess the ability to migrate to areas of inflammation and promote the regeneration of damaged tissue. However, it remains unclear how radiation influences this capacity of MSC in the head and neck region.

METHODS

Two types of MSCs of the head and neck region (mucosa [mMSC] and parotid gland [pMSC]) were isolated, cultured and exposed to single radiation dosages of 2 Gy/day up to 10 days. Effects on morphology, colony forming ability, apoptosis, chemokine receptor expression, cytokine secretion, and cell migration were analyzed.

RESULTS

Although MSC preserved MSC-specific regenerative abilities and immunomodulatory properties following irradiation in our in vitro model, we found a deleterious impact on colony forming ability, especially in pMSC.

CONCLUSIONS

MSC exhibited robustness and activation upon radiation for the support of tissue regeneration, but lost their potential to replicate, thus possibly leading to depletion of the local MSC-pool after irradiation.

Role of Steroids in Preventing Osteoradionecrosis of the Head and Neck: A Systematic Review

Objective:

The aim of this study was to summarize the effectiveness of steroids in the prevention of osteoradionecrosis of the head and neck.

Data Sources:

PubMED, MEDLINE, Embase, Google Scholar, and Cochrane trial registries.

Methods:

A systematic review of these data sources was performed through September 2018 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included were English-language studies evaluating patients of all age groups diagnosed with head and neck cancer who underwent radiation therapy while receiving peritreatment steroids compared with those who did not receive steroids.

Results:

Two retrospective cohort studies were identified for qualitative review. On the basis of analysis of 25 328 participants (36-82 years of age) with head and neck cancer who underwent radiation therapy, the use of peritreatment steroids was associated with a significantly lower risk for osteoradionecrosis in both studies, with a hazard ratio of 0.74 (95% confidence interval, 0.59-0.94; P = .012) and a relative risk of 0.04 (95% confidence interval, 0.003-0.560; P = .017). Meta-analysis was precluded by clinical and statistical heterogeneity. Overall, the studies were of limited quality with high risk for bias and poor methodology.

Conclusions:

Limited retrospective data suggest that steroids are predictive of a reduced risk for osteoradionecrosis; however, no definitive conclusions can be made given the poor quality of the available literature. Well-designed, comparison-controlled trials are needed to clarify the promising role of steroids in the prevention of osteoradionecrosis of the head and neck.

Benefits of Oral Nutritional Supplements in Patients with Locally Advanced Nasopharyngeal Cancer during Concurrent Chemoradiotherapy: An Exploratory Prospective Randomized Trial

BACKGROUND

Weight loss during chemoradiotherapy is a major problem in patients with head and neck cancer. The aim of this study was to evaluate the effect of ONS on weight, nutritional status and quality of life (QOL) in patients with loco-regionally advanced nasopharyngeal cancer (NPC) undergoing chemoradiotherapy.

METHODS

Patients with locally advanced NPC treated at a tertiary hospital in China prior to curative chemoradiotherapy were eligible for this exploratory randomized study. Patients were assigned to either the intervention or the control group based on a computer-generated randomization sequence. The intervention group commenced ONS at the start of chemoradiotherapy. Outcomes included body weight, BMI, nutritional status and QOL.

RESULTS

From June 2015 to June 2016, 50 patients with NPC were randomized to intervention and 50 to the control group. Patients in the ONS group had a higher body weight at the end of chemoradiotherapy (59.11 kg vs 58.14 kg, p = 0.036). A higher BMI and prealbumin were observed in the ONS group (p = 0.021 and p = 0.048, respectively). No other differences were found for nutritional status, QOL or clinical outcomes.

CONCLUSION

ONS had beneficial outcomes in terms of reducing weight loss, minimizing BMI decrease and increasing protein intake in loco-regionally advanced NPC patients during chemoradiotherapy.

Cordycepin, isolated from medicinal fungus Cordyceps sinensis, enhances radiosensitivity of oral cancer associated with modulation of DNA damage repair

Concurrent chemotherapy and radiotherapy (RT) is important for controlling oral squamous cell carcinoma (OSCC), which is often accompanied by significant acute and late toxicities. We investigated whether cordycepin, a small molecule extracted from Cordyceps sinensis, could enhance the radiosensitivity of oral cancer cells. Using colony formation assay, we demonstrated that cordycepin induces radiosensitizing effects on two OSCC cells. DNA histogram analysis showed that cordycepin combined with RT prolonged the RT-induced G2/M phase arrest. It protracted the duration of DNA double strand breaks, which was detected by immunofluorescent staining of phosphorylated histone H2AX (γ-H2AX). The underlying molecular mechanism might involve the downregulation of protein expression related to DNA damage repair, including phosphorylated ataxia-telangiectasia mutated (p-ATM) and phosphorylated checkpoint kinase 2. Reciprocal upregulation of phosphorylated checkpoint kinase 1 (Chk1) expression was noted, and the radiosensitizing effect of cordycepin could be further augmented by Chk1 mRNA knockdown, indicating a compensatory DNA repair machinery involving phosphorylation of Chk1. In vivo, the combination of cordycepin and RT exhibited greater growth inhibition on xenografts and stronger apoptosis induction than RT alone, without exacerbating major toxicities. In conclusion, cordycepin increased the radiosensitivity of OSCC cells, which is associated with the modulation of RT-induced DNA damage repair machinery.

A Quantitative Clinical Decision-Support Strategy Identifying Which Patients With Oropharyngeal Head and Neck Cancer May Benefit the Most From Proton Radiation Therapy

PURPOSE

Developing a quantitative decision-support strategy estimating the impact of normal tissue complications from definitive radiation therapy (RT) for head and neck cancer (HNC). We developed this strategy to identify patients with oropharyngeal HNC who may benefit most from receiving proton RT.

METHODS AND MATERIALS

Recent normal tissue complication probability (NTCP) models for dysphagia, esophagitis, hypothyroidism, xerostomia, and oral mucositis were used to estimate NTCP for 33 patients with oropharyngeal HNC previously treated with photon intensity modulated radiation therapy (IMRT). Comparative proton therapy plans were generated using clinical protocols for HNC RT at a collaborating proton center. Organ-at-risk (OAR) doses from photon and proton RT plans were used to calculate NTCPs; Monte Carlo sampling 10,000 times was used for each patient to account for model parameter uncertainty. The latency and duration of each complication were modeled from calculated NTCP, accounting for age-, sex-, smoking- and p16-specific conditional survival probability. Complications were then assigned quality-adjustment factors based on severity to calculate quality-adjusted life years (QALYs) lost from each complication.

RESULTS

Based on our institutional-delivered photon IMRT doses and the achievable proton therapy doses, the average QALY reduction from all HNC RT complications for photon and proton therapy was 1.52 QALYs versus 1.15 QALYs, with proton therapy sparing 0.37 QALYs on average (composite 95% confidence interval, 0.27-2.53 QALYs). Long-term complications (dysphagia and xerostomia) contributed most to the QALY reduction. The QALYs spared with proton RT varied considerably among patients, ranging from 0.06 to 0.84 QALYs. Younger patients with p16-positive tumors who smoked ≤10 pack-years may benefit most from proton therapy, although this finding should be validated using larger patient series. A sensitivity analysis reducing photon IMRT doses to all OARs by 20% resulted in no overall estimated benefit with proton therapy with -0.02 QALYs spared, although some patients still had an estimated benefit in this scenario, ranging from -0.50 to 0.43 QALYs spared.

CONCLUSIONS

This quantitative decision-support strategy allowed us to identify patients with oropharyngeal cancer who might benefit the most from proton RT, although the estimated benefit of proton therapy ultimately depends on the OAR doses achievable with modern photon IMRT solutions. These results can help radiation oncologists and proton therapy centers optimize resource allocation and improve quality of life for patients with HNC.

Revisiting the dose constraints for head and neck OARs in the current era of IMRT

Head and neck cancer poses a particular challenge in radiation therapy, whilst being an effective treatment modality it requires very high doses of radiation to provide effective therapy. This is further complicated by the fact that the head and neck region contains a large number of radiosensitive tissues, often resulting in patients experiencing debilitating normal tissue complications. In the era of intensity-modulated radiation therapy (IMRT) treatments can be delivered using non-uniform dose distributions selectively aimed at reducing the dose to critical organs-at-risk while still adequately covering the tumor target. Dose-volume constraints for the different risk organs play a vital role in one's ability to devise the best IMRT treatment plan for a head and neck cancer patient. To this end, it is pivotal to have access to the latest and most relevant dose constraints available and as such the goal of this review is to provide a summary of suggested dose-volume constraints for head and neck cancer RT that have been published after the QUANTEC reports were made available in early 2010.

Anatomical change during radiotherapy for head and neck cancer, and its effect on delivered dose to the spinal cord

•

A cohort of 133 head & neck cancer patients treated with TomoTherapy was examined.

•

Differences between planned and delivered maximum spinal cord dose were small.

•

Substantial weight loss and anatomical change during treatment was observed.

•

No link between weight loss or anatomical change, and dose differences was seen.

Background and purpose

The impact of weight loss and anatomical change during head and neck (H&N) radiotherapy on spinal cord dosimetry is poorly understood, limiting evidence-based adaptive management strategies.

Materials and methods

133 H&N patients treated with daily mega-voltage CT image-guidance (MVCT-IG) on TomoTherapy, were selected. Elastix software was used to deform planning scan SC contours to MVCT-IG scans, and accumulate dose. Planned (D_P) and delivered (D_A) spinal cord D_2% (SCD_2%) were compared. Univariate relationships between neck irradiation strategy (unilateral vs bilateral), T-stage, N-stage, weight loss, and changes in lateral separation (LND) and CT slice surface area (SSA) at C1 and the superior thyroid notch (TN), and ΔSCD_2% [(D_A – D_P) D_2%] were examined.

Results

The mean value for (D_A – D_P) D_2% was −0.07 Gy (95%CI −0.28 to 0.14, range −5.7 Gy to 3.8 Gy), and the mean absolute difference between D_P and D_A (independent of difference direction) was 0.9 Gy (95%CI 0.76–1.04 Gy). Neck treatment strategy (p = 0.39) and T-stage (p = 0.56) did not affect ΔSCD_2%. Borderline significance (p = 0.09) was seen for higher N-stage (N2-3) and higher ΔSCD_2%. Mean reductions in anatomical metrics were substantial: weight loss 6.8 kg; C1LND 12.9 mm; C1SSA 12.1 cm²; TNLND 5.3 mm; TNSSA 11.2 cm², but no relationship between weight loss or anatomical change and ΔSCD_2% was observed (all r² < 0.1).

Conclusions

Differences between delivered and planned spinal cord D_2% are small in patients treated with daily IG. Even patients experiencing substantial weight loss or anatomical change during treatment do not require adaptive replanning for spinal cord safety.

The interobserver agreement in the detection of recurrent HNSCC using MRI including diffusion weighted MRI

INTRODUCTION

For the detection of local recurrences of head and neck squamous cell carcinomas (HNSCC) after (chemo)radiation, diagnostic imaging is generally performed. Diffusion weighted magnetic resonance imaging (DW-MRI) has been proven to be able to adequately diagnose the presence of cancer. However evaluation of DW-MR images for recurrences is difficult and could be subject to individual interpretation.

AIM

To determine the interobserver agreement, intraobserver agreement and influence of experience of radiologists in the assessment of DW-MRI in patients clinically suspected of local recurrent HNSCC after (chemo)radiation.

METHODS

Ten experienced head and neck radiologists assessed follow-up MRI including DW-MRI series of 10 patients for the existence of local recurrence on a two point decision scale (local recurrence or local control). Patients were clinically suspected for a recurrence of laryngeal (n = 3), hypopharyngeal (n = 3) or oropharyngeal (n = 4) cancer after (chemo)radiation with curative intent. Fleiss' and Cohen's Kappa were used to determine interobserver agreement and intraobserver agreement, respectively.

RESULTS

Interobserver agreement was κ = 0.55. Intraobserver agreement was κ = 0.80. Prior experience within the field of radiology and with DW-MRI had no significant influence on the scoring.

CONCLUSION

For the assessment of HNSCC recurrence after (chemo)radiation by DW-MRI, moderate interobserver agreement and substantial intraobserver agreement was found.

Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device

Radiation therapy is a useful and standard tumor treatment strategy. Despite recent advances in delivery of ionizing radiation, survival rates for some cancer patients are still low because of recurrence and radioresistance. This is why many novel approaches have been explored to improve radiotherapy outcome. Some strategies are focused on enhancement of accuracy in ionizing radiation delivery and on the generation of greater radiation beams, for example with a higher dose rate. In the present study we proposed an in vitro research of the biological effects of very high dose rate beam on SK-Mel28 and A375, two radioresistant human melanoma cell lines. The beam was delivered by a pulsed plasma device, a "Mather type" Plasma Focus for medical applications. We hypothesized that this pulsed X-rays generator is significantly more effective to impair melanoma cells survival compared to conventional X-ray tube. Very high dose rate treatments were able to reduce clonogenic efficiency of SK-Mel28 and A375 more than the X-ray tube and to induce a greater, less easy-to-repair DNA double-strand breaks. Very little is known about biological consequences of such dose rate. Our characterization is preliminary but is the first step toward future clinical considerations.

Segmentation of parotid glands from registered CT and MR images

PURPOSE

To develop an automatic multimodal method for segmentation of parotid glands (PGs) from pre-registered computed tomography (CT) and magnetic resonance (MR) images and compare its results to the results of an existing state-of-the-art algorithm that segments PGs from CT images only.

METHODS

Magnetic resonance images of head and neck were registered to the accompanying CT images using two different state-of-the-art registration procedures. The reference domains of registered image pairs were divided on the complementary PG regions and backgrounds according to the manual delineation of PGs on CT images, provided by a physician. Patches of intensity values from both image modalities, centered around randomly sampled voxels from the reference domain, served as positive or negative samples in the training of the convolutional neural network (CNN) classifier. The trained CNN accepted a previously unseen (registered) image pair and classified its voxels according to the resemblance of its patches to the patches used for training. The final segmentation was refined using a graph-cut algorithm, followed by the dilate-erode operations.

RESULTS

Using the same image dataset, segmentation of PGs was performed using the proposed multimodal algorithm and an existing monomodal algorithm, which segments PGs from CT images only. The mean value of the achieved Dice overlapping coefficient for the proposed algorithm was 78.8%, while the corresponding mean value for the monomodal algorithm was 76.5%.

CONCLUSIONS

Automatic PG segmentation on the planning CT image can be augmented with the MR image modality, leading to an improved RT planning of head and neck cancer.

Effectiveness of tomotherapy vs linear accelerator image-guided intensity-modulated radiotherapy for localized pharyngeal cancer treated with definitive concurrent chemoradiotherapy: a Taiwanese population-based propensity score-matched analysis

OBJECTIVE

This study used a population-based propensity score (PS)-matched analysis to compare the effectiveness of tomotherapy-based image-guided intensity-modulated radiotherapy (referred to as T-IMRT) with that of linear accelerator based (referred to as L-IMRT) for clinically localized pharyngeal cancer (LPC, divided into nasopharyngeal cancer and non-nasopharyngeal cancer) with definitive concurrent chemoradiotherapy (CCRT).

METHODS

Eligible LPC patients diagnosed between 2007 and 2014 were identified among all citizens in Taiwan from the Health and Welfare Data Science Center database. A PS-matched sample based on the PS estimated from the covariables of interest was constructed to compare the effectiveness of T-IMRT with L-IMRT. In the primary analysis, overall survival (OS) was compared for assessment of effectiveness. We also evaluated freedom from local regional recurrence and pharyngeal cancer-specific survival and performed supplementary analyses.

RESULTS

The study population included 960 patients equally divided into two groups. OS did not differ significantly between the T-IMRT and L-IMRT groups (hazard ratio for death: 0.82, p = 0.15, 5-year OS rate: 79 and 74% for T-IMRT and L-IMRT, respectively), and there were no significant differences in the other endpoints or supplementary analyses.

CONCLUSION

For LPC patients treated with definitive CCRT, we found no significant difference in disease control or survival between the T-IMRT and L-IMRT groups. However, further studies, especially randomized trials or studies focusing on other dimensions, such as quality of life, are needed. Advances in knowledge: We provide the first population-based study, as well as the largest study, on the clinical effectiveness of T-IMRT compared with L-IMRT in conjunction with CCRT in LPC patients.

Molecular Imaging-Guided Radiotherapy for the Treatment of Head-and-Neck Squamous Cell Carcinoma: Does it Fulfill the Promises?

With the routine use of intensity modulated radiation therapy for the treatment of head-and-neck squamous cell carcinoma allowing highly conformed dose distribution, there is an increasing need for refining both the selection and the delineation of gross tumor volumes (GTV). In this framework, molecular imaging with positron emission tomography and magnetic resonance imaging offers the opportunity to improve diagnostic accuracy and to integrate tumor biology mainly related to the assessment of tumor cell density, tumor hypoxia, and tumor proliferation into the treatment planning equation. Such integration, however, requires a deep comprehension of the technical and methodological issues related to image acquisition, reconstruction, and segmentation. Until now, molecular imaging has had a limited value for the selection of nodal GTV, but there are increasing evidences that both FDG positron emission tomography and diffusion-weighted magnetic resonance imaging has a potential value for the delineation of the primary tumor GTV, effecting on dose distribution. With the apprehension of the heterogeneity in tumor biology through molecular imaging, growing evidences have been collected over the years to support the concept of dose escalation/dose redistribution using a planned heterogeneous dose prescription, the so-called "dose painting" approach. Validation trials are ongoing, and in the coming years, one may expect to position the dose painting approach in the armamentarium for the treatment of patients with head-and-neck squamous cell carcinoma.

Comparative Analysis of Clinical and Pathological Lymph Node Staging Data in Head and Neck Squamous Cell Carcinoma Patients Treated at the General Hospital Vienna

Background

Results from publications evaluating discrepancies between clinical staging data in relation to pathological findings demonstrate that a significant number of head and neck squamous cell carcinoma (HNSCC) patients are not correctly staged. The aim of this retrospective study was to analyze potential discrepancies of radiological assessment versus pathological data of regional lymph node involvement and to compare the results with data published in the literature.

Patients and methods

In a retrospective analysis we focused on patients with HNSCC routinely treated by surgery plus postoperative radiotherapy between 2002 and 2012. For inclusion, complete pre-operative clinical staging information with lymph node status and patho-histological information on involved lymph node regions as well as survival outcome data were mandatory. We included 87 patients (UICC stage III-IV 90.8%) for which the aforementioned data obtained by CT or MRI were available. Overall survival rates were estimated by the Kaplan-Meier method. The Pearson correlation coefficient and Spearman's rank correlation coefficient (non-linear relationship) was calculated.

Results

Discrepancies at the level of overall tumour stage assessment were noticed in 27.5% of all cases. Thereof, 5.7% were assigned to patho-histological up-staging or down-staging of the primary tumour. At the lymph node level, 11.5% of the patients were downstaged, and 10.3% were upstaged.

Conclusions

The study showed that in approximately one-fifth (21.8%) of the patients, lymph node assessment by CT or MRI differs from the pathologic staging, an outcome that corresponds well with those published by several other groups in this field.

Neutrophil-Based Drug Delivery Systems

White blood cells (WBCs) are a major component of immunity in response to pathogen invasion. Neutrophils are the most abundant WBCs in humans, playing a central role in acute inflammation induced by pathogens. Adhesion to vasculature and tissue infiltration of neutrophils are key processes in acute inflammation. Many inflammatory/autoimmune disorders and cancer therapies have been found to be involved in activation and tissue infiltration of neutrophils. A promising strategy to develop novel targeted drug delivery systems is the targeting and exploitation of activated neutrophils. Herein, a new drug delivery platform based on neutrophils is reviewed. There are two types of drug delivery systems: neutrophils as carriers and neutrophil-membrane-derived nanovesicles. It is discussed how nanoparticles hijack neutrophils in vivo to deliver therapeutics across blood vessel barriers and how neutrophil-membrane-derived nanovesicles target inflamed vasculature. Finally, the potential applications of neutrophil-based drug delivery systems in treating inflammation and cancers are presented.

Patients with advanced periodontal disease before intensity-modulated radiation therapy are prone to develop bone healing problems: a 2-year prospective follow-up study

PURPOSE

Intensity-modulated radiation therapy (IMRT) has changed radiation treatment of head and neck cancer (HNC). However, it is still unclear if and how IMRT changes oral morbidity outcomes. In this prospective study, we assessed the outcome of reducing post-IMRT sequelae by means of pre-radiation dental screening and eliminating oral foci.

METHODS

All consecutive dentate patients > 18 years, diagnosed with primary oral or oropharyngeal carcinoma, referred for pre-treatment dental screening between May 2011 and May 2013, were included and followed for 2 years. Patients were treated with IMRT or IMRT with chemotherapy (CHIMRT). Dental screening data, demographic data, and data on oral sequelae during follow-up were recorded. Diagnosed oral foci were treated before start of the radiation therapy.

RESULTS

Oral foci were found in 44/56 (79%) patients, consisting predominantly of periodontal breakdown. Bone healing problems after radiotherapy occurred more often in patients with periodontal pockets ≥ 6 mm at baseline (19 vs. 4% in patients with pockets < 6 mm). Osteoradionecrosis developed in 4/56 patients (7%) during follow-up. In line with this observation, multiple logistic regression analysis showed that the periodontal inflamed surface area, which is higher in patients with more severe periodontal disease, predicted that a patient has a higher risk on developing osteoradionecrosis or bone healing problems (p = 0.028).

CONCLUSIONS

Patients with severe periodontal disease before IMRT/CHIMRT are more prone to develop bone healing problems post-radiotherapy.

A feasibility study on adaptive 18F-FDG-PET-guided radiotherapy for recurrent and second primary head and neck cancer in the previously irradiated territory

PURPOSE

To evaluate feasibility, disease control, survival, and toxicity after adaptive ¹⁸F-fluorodeoxyglucose (FDG) positron emisson tomography (PET) guided radiotherapy in patients with recurrent and second primary head and neck squamous cell carcinoma.

METHODS

A prospective trial investigated the feasibility of adaptive intensity modulated radiotherapy (IMRT) ± concomitant cetuximab in 10 patients. The primary endpoint was achieving a 2-year survival free of grade >3 toxicity in ≥30% of patients. Three treatment plans based on 3 PET/CT scans were consecutively delivered in 6 weeks. The range of dose painting was 66.0-85.0 Gy in the dose-painted tumoral volumes in 30 fractions.

RESULTS

Two-year locoregional and distant control rates were 38 and 76%, respectively. Overall and disease-free survival at 2 years was 20%. No grade 4 or 5 acute toxicity was observed in any of the patients, except for arterial mucosal hemorrhage in 1 patient. Three months after radiotherapy, grade 4 dysphagia and mucosal wound healing problems were observed in 1/7 and 1/6 of patients, respectively. Grade 5 toxicity (fatal bleeding) was seen in 2 patients, at 3.8 and 4.1 months of follow-up. Data on 2‑year toxicity could only be assessed in 1 of the 2 surviving patients, in whom grade 4 mucosal wound healing problems were observed; no other grade >3 toxicity was observed. In this respect, a 30% 2‑year survival free of grade >3 toxicity will not be achieved.

CONCLUSIONS

Adaptive PET-guided reirradiation is feasible. However, due to slow accrual and treatment results that seemed inconsistent with achieving the primary endpoint, the trial was stopped early.

An update on radiation therapy in head and neck cancers

INTRODUCTION

Technological and technical improvements allowed for significant advances in the field of radiation therapy (RT) of head and neck cancer (HNC). Several organ-sparing strategies have been investigated with the objective to decrease acute and long-term adverse effects and, subsequently, to assure a better quality of life in patients affected by HNC. In this context, intensity modulated irradiation and the use of multimodality-imaging could help clinicians to obtain a rapid dose fall off towards surrounding healthy tissues and a better delineation of targets volumes and organs at risk. Areas covered: A literature review was performed with the aim to offer an update on radiation therapy in HNC. Expert commentary: During these last years, radiation oncologists have observed a continuous changing regarding radiation treatment for HNC. The adoption of intensity-modulated RT (IMRT) and the use of multimodality-imaging for tumor volume definition and organs at risk or delineation have improved the clinical outcomes of HNC patients. In the future, a better integration of functional imaging for target volume delineation as well as adaptive delivery strategies will allow to further personalize radiation oncology in HNC. Furthermore, the latest breakthrough technologies, such as magnetic resonance imaging (MRI)-linacs and heavy particles technologies have a great potential to improve treatment-related quality of life in HNC. Future studies are needed to demonstrate the clinical advantages of these new RT technologies in HNC.

Prediction of radiotherapy response with a 5-microRNA signature-based nomogram in head and neck squamous cell carcinoma

Radiotherapy is unlikely to benefit all patients with head and neck squamous cell carcinoma (HNSCC). Therefore, novel method is warranted to predict the radiotherapy response. Our study aimed to construct a microRNA (miRNA)‐based nomogram to predict clinical outcomes of patients with HNSCC receiving radiotherapy. We screened out 56 differential miRNAs by analyzing 44 paired tumor and adjacent normal samples miRNA expression profiles from The Cancer Genome Atlas (TCGA). A total of 307 patients with HNSCC receiving adjuvant radiotherapy were randomly divided into a training set (n = 154) and a validation set (n = 153). In the training set, we combined the differential miRNA profiles with clinical outcomes, and LASSO regression model was applied to establish a 5‐miRNA signature. The prediction accuracy of the 5‐miRNA signature was further validated. In addition, target genes of these miRNAs were predicted, and Gene Ontology (GO) analysis as well as KEGG pathway analysis was executed. A 5‐miRNA signature including miR‐99a, miR‐31, miR‐410, miR‐424, and miR‐495 was identified. With a cutoff value of 1.2201 from Youden's index, the training set was divided into high‐risk and low‐risk groups, and the 5‐year overall survival was significantly different (30% vs. 73%, HR 3.65, CI 2.46–8.16; P < 0.0001). Furthermore, our 5‐miRNA signature revealed that only low‐risk group would benefit from radiotherapy. Then, a nomogram combining 5‐miRNA signature with clinical variables to predict radiotherapy response was constructed. The analysis of 108 target genes of these miRNAs revealed some potential mechanisms in HNSCC radiotherapy response for future investigations. In conclusion, the 5‐miRNA signature‐based nomogram is useful in predicting radiotherapy response in HNSCC and might become a promising tool to optimize radiation strategies.