Artificial intelligence to predict outcomes of head and neck radiotherapy

Head and neck radiotherapy induces important toxicity, and its efficacy and tolerance vary widely across patients. Advancements in radiotherapy delivery techniques, along with the increased quality and frequency of image guidance, offer a unique opportunity to individualize radiotherapy based on imaging biomarkers, with the aim of improving radiation efficacy while reducing its toxicity. Various artificial intelligence models integrating clinical data and radiomics have shown encouraging results for toxicity and cancer control outcomes prediction in head and neck cancer radiotherapy. Clinical implementation of these models could lead to individualized risk-based therapeutic decision making, but the reliability of the current studies is limited. Understanding, validating and expanding these models to larger multi-institutional data sets and testing them in the context of clinical trials is needed to ensure safe clinical implementation. This review summarizes the current state of the art of machine learning models for prediction of head and neck cancer radiotherapy outcomes.

Cardiovascular Manifestations From Therapeutic Radiation: A Multidisciplinary Expert Consensus Statement From the International Cardio-Oncology Society

Radiation therapy is a cornerstone of cancer therapy, with >50% of patients undergoing therapeutic radiation. As a result of widespread use and improved survival, there is increasing focus on the potential long-term effects of ionizing radiation, especially cardiovascular toxicity. Radiation therapy can lead to atherosclerosis of the vasculature as well as valvular, myocardial, and pericardial dysfunction. We present a consensus statement from the International Cardio-Oncology Society based on general principles of radiotherapy delivery and cardiovascular risk assessment and risk mitigation in this population. Anatomical-based recommendations for cardiovascular management and follow-up are provided, and a priority is given to the early detection of atherosclerotic vascular disease on imaging to help guide preventive therapy. Unique management considerations in radiation-induced cardiovascular disease are also discussed. Recommendations are based on the most current literature and represent a unanimous consensus by the multidisciplinary expert panel.

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Radiation therapy leads to short- and long-term cardiovascular adverse effects of the vasculature and the heart, including valvular, myocardial, and pericardial disease.

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Computed tomography scans conducted for radiation planning or cancer staging provide an available opportunity to detect asymptomatic atherosclerosis and direct preventive therapies.

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Additional practical screening recommendations for cardiovascular disease based on anatomical exposure are provided.

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There are unique considerations in the management of radiation-induced cardiovascular disease; contemporary percutaneous treatment is often preferred over surgical options.

The role of ALDH2 in tumorigenesis and tumor progression: Targeting ALDH2 as a potential cancer treatment

A major mitochondrial enzyme for protecting cells from acetaldehyde toxicity is aldehyde dehydrogenase 2 (ALDH2). The correlation between ALDH2 dysfunction and tumorigenesis/growth/metastasis has been widely reported. Either low or high ALDH2 expression contributes to tumor progression and varies among different tumor types. Furthermore, the ALDH2∗2 polymorphism (rs671) is the most common single nucleotide polymorphism (SNP) in Asia. Epidemiological studies associate ALDH2∗2 with tumorigenesis and progression. This study summarizes the essential functions and potential ALDH2 mechanisms in the occurrence, progression, and treatment of tumors in various types of cancer. Our study indicates that ALDH2 is a potential therapeutic target for cancer therapy.

Identifying organs at risk for radiation-induced late dysphagia in head and neck cancer patients

Background and purpose

Dysphagia is a common, severe and dose-limiting toxicity after oncological treatment of head and neck cancer (HNC). This study aims to investigate relationships between radiation doses to structures involved in normal swallowing and patient-reported as well as clinically measured swallowing function in HNC patients after curative (chemo-) radiation therapy (RT) with focus on late effects.

Materials and methods

Patients (n = 90) with HNC curatively treated with RT ± chemotherapy in 2007-2015 were assessed for dysphagia post-treatment by telephone interview and videofluoroscopy (VFS). A study-specific symptom score was used to determine patient-reported dysphagia. The Penetration-Aspiration Scale (PAS) was applied to determine swallowing function by VFS (PAS ≥ 4/ ≥ 6 = moderate/severe dysphagia). Thirteen anatomical structures involved in normal swallowing were individually delineated on the patients' original planning CT scans and associated dose-volume histograms (DVHs) retrieved. Relationships between structure doses and late toxicity were investigated through univariable and multivariable logistic regression analysis (UVA/MVA) accounting for effects by relevant clinical factors.

Results

Median assessment time was 7 months post-RT (range: 5-34 months). Mean dose to the contralateral parotid gland and supraglottic larynx as well as maximum dose to the contralateral anterior digastric muscle predicted patient-reported dysphagia (AUC = 0.64-0.67). Mean dose to the pharyngeal constrictor muscle, the larynx, the supraglottic larynx and the epiglottis, as well as maximum dose to the contralateral submandibular gland predicted moderate and severe dysphagia by VFS (AUC = 0.71-0.80).

Conclusion

The patients in this cohort were consecutively identified pre-treatment, and were structurally approached and assessed for dysphagia after treatment at a specific time point. In addition to established dysphagia organs-at-risk (OARs), our data suggest that epiglottic and submandibular gland doses are important for swallowing function post-RT. Keeping DVH thresholds below V60 = 60% and V60 = 17%, respectively, may increase chances to reduce occurrence of severe late dysphagia. The results need to be externally validated in future studies.

Prospective quantitative quality assurance and deformation estimation of MRI-CT image registration in simulation of head and neck radiotherapy patients

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MRI-CT deformable image registration was not superior to rigid registration.

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Dice similarity coefficients were 0.65, 0.62, and 0.63 for deformable registrations.

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Dice similarity coefficient was 0.63 for rigid registration.

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Registration quality was superior in muscle and gland compared to bone and vessel.

Background

MRI-guided radiotherapy planning (MRIgRT) may be superior to CT-guided planning in some instances owing to its improved soft tissue contrast. However, MR images do not communicate tissue electron density information necessary for dose calculation and therefore must either be co-registered to CT or algorithmically converted to synthetic CT. No robust quality assessment of commercially available MR-CT registration algorithms is yet available; thus we sought to quantify MR-CT registration formally.

Methods

Head and neck non-contrast CT and T2 MRI scans acquired with standard treatment immobilization techniques were prospectively acquired from 15 patients. Per scan, 35 anatomic regions of interest (ROIs) were manually segmented. MRIs were registered to CT rigidly (RIR) and by three commercially available deformable registration algorithms (DIR). Dice similarity coefficient (DSC), Hausdorff distance mean (HD mean) and Hausdorff distance max (HD max) metrics were calculated to assess concordance between MRI and CT segmentations. Each DIR algorithm was compared to DIR using the nonparametric Steel test with control for individual ROIs (n = 105 tests) and for all ROIs in aggregate (n = 3 tests). The influence of tissue type on registration fidelity was assessed using nonparametric Wilcoxon pairwise tests between ROIs grouped by tissue type (n = 12 tests). Bonferroni corrections were applied for multiple comparisons.

Results

No DIR algorithm improved the segmentation quality over RIR for any ROI nor all ROIs in aggregate (all p values >0.05). Muscle and gland ROIs were significantly more concordant than vessel and bone, but DIR remained non-different from RIR.

Conclusions

For MR-CT co-registration, our results question the utility and applicability of commercially available DIR over RIR alone. The poor overall performance also questions the feasibility of translating tissue electron density information to MRI by CT registration, rather than addressing this need with synthetic CT generation or bulk-density assignment.

Detection of high PD-L1 expression in oral cancers by a novel monoclonal antibody L1Mab-4

Programmed cell death-ligand 1 (PD-L1), which is a ligand of programmed cell death-1 (PD-1), is a type I transmembrane glycoprotein that is expressed on antigen-presenting cells and several tumor cells, including melanoma and lung cancer cells. There is a strong correlation between human PD-L1 (hPD-L1) expression on tumor cells and negative prognosis in cancer patients. In this study, we produced a novel anti-hPD-L1 monoclonal antibody (mAb), L₁Mab-4 (IgG_2b, kappa), using cell-based immunization and screening (CBIS) method and investigated hPD-L1 expression in oral cancers. L₁Mab-4 reacted with oral cancer cell lines (Ca9-22, HO-1-u-1, SAS, HSC-2, HSC-3, and HSC-4) in flow cytometry and stained oral cancers in a membrane-staining pattern. L₁Mab-4 stained 106/150 (70.7%) of oral squamous cell carcinomas, indicating the very high sensitivity of L₁Mab-4. These results indicate that L₁Mab-4 could be useful for investigating the function of hPD-L1 in oral cancers.

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Programmed cell death-ligand 1 (PD-L1) is expressed in many cancers.

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PD-L1 expression has not been fully investigated in oral cancers.

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A novel anti-PD-L1 mAb L₁Mab-4 was developed in this study.

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L₁Mab-4 stained 70.7% of oral SCCs in a membrane-staining pattern.

Dusquetide: Reduction in oral mucositis associated with enduring ancillary benefits in tumor resolution and decreased mortality in head and neck cancer patients

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Dusquetide was well-tolerated during treatment and throughout the 12-month follow-up.

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Dusquetide did not interfere with tumor treatment.

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Dusquetide treated groups had less mortality that placebo treated groups through the 12-month follow-up.

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Dusquetide treated groups had fewer “non-fungal” infections than placebo treated groups.

Innate immunity is a key component in the pathogenesis of oral mucositis, a universal toxicity of chemoradiation therapy (CRT). Dusquetide, a novel Innate Defense Regulator, has demonstrated both nonclinical and clinical efficacy in ameliorating severe oral mucositis (SOM). Long term follow-up studies from the Phase 2 clinical study evaluating dusquetide as a treatment for SOM in head and neck cancer (HNC) patients receiving CRT have now been completed. Extended analysis indicates that dusquetide therapy was well-tolerated and did not contribute to increased infection, tumor growth or mortality. Potential ancillary benefits of duquetide therapy were also identified.