Systematic dosimetric evaluation of risk of osteoradionecrosis (DERO): First results of dose reporting for preventing teeth osteoradionecrosis after head and neck irradiation

PURPOSE

OsteoRadioNecrosis (ORN) is a late complication of radiation for head and neck cancer. Predicting ORN is a major challenge. We developed DERO (Dosimetric Evaluation of Risk of ORN), a semi-automatic tool which reports doses delivered to tooth-bearing sectors, to guide post-therapeutic dental care. We present the method and the first results of a 125-patient prospective cohort.

MATERIAL AND METHODS

Dosimetric data of patients treated with IMRT for head and neck cancer were prospectively segmented to the DERO algorithm. Four arches corresponding to 8-tooth sectors were semi-automatically generated. Thirty-two cylindrical Regions Of Interest (ROI) corresponding to each tooth and surrounding periodontium were created by linear interpolation. Mean doses (Dmean) of ROI were extracted and included in a database, along with data about primary tumor site, laterality and dose values from organs at risk. Dmean to tooth sectors were computed for molar sectors, (teeth X5 to X8) and anterior sectors (teeth X1 to X4). An individual dose map was generated and delivered to patients and dentists.

RESULTS

Dosimetric data from 125 patients treated with Tomotherapy® were prospectively collected and analyzed: 9 parotid tumors (PA), 41 Sub-Hyoid tumors (larynx, hypopharynx) (SH), 43 Oropharynx tumors (OR), 32 Oral Cavity tumors (OC). Irradiation was unilateral for 100% of PA tumors (9), 12% of OR tumors (5) and 47% of OC tumors (15). For unilateral cervical irradiation, Dmean in ipsilateral molar sectors was 54Gy for OC tumors, 45Gy for OR tumors, 20Gy for PA tumors. For Oral Cavity bilateral irradiation, Dmean was high in all tooth sectors, 49 to 55Gy. For SH tumors, Dmean in molar sectors was 27Gy. A dose gradient of 10 to 20Gy was observed between molar and anterior sectors whether radiation was uni or bilateral.

CONCLUSION

Mandibular molar sectors of Oropharynx and Oral Cavity tumors were exposed to high Dmean of 40 to 50Gy. On the other hand, tooth sectors received lower doses for SH radiation. The DERO tool guide post-radiation dental care with a personalized dosimetric cartography to patient. With data update and patient follow-up, we will be able to determine ORN risk after head and neck radiation.

Visual outcomes of macular melanocytic lesions after early or delayed proton beam therapy

PURPOSE

During their initial management, some macular melanocytic lesions can be closely monitored to wait for a documented growth before advocating a treatment by irradiation. However, the visual outcomes of this strategy have not yet been assessed. This study compares the visual outcomes of macular melanocytic lesions that underwent delayed proton beam therapy (PBT) after an initial observation to those treated early.

METHODS

A total of 162 patients with suspicious melanocytic lesions whose margins were located within 3 mm of the fovea were recruited from two French ocular oncology centers.

RESULTS

Overall, 82 patients treated with PBT within 4 months after the initial visit (early PBT group) were compared to 24 patients treated with delayed PBT (delayed PBT group) and 56 patients not treated with PBT (observation group). Visual acuity was not significantly different between baseline and last visit in the observation group (p = 0.325). Between baseline and last visit, the median [IQR] loss in visual acuity was significant in both the early (0.7 [0.2; 1.8], p < 0.001) and the delayed (0.5 [0.2; 1.5], p < 0.001) PBT groups. After irradiation, there was no significant difference between the early and delayed PBT groups for visual loss (p = 0.575), diameter reduction (p = 0.190), and thickness lowering (p = 0.892). In multivariate analysis, history of diabetes mellitus and Bruch's membrane rupture remained significantly associated with greater visual loss (p = 0.036 and p = 0.002, respectively).

CONCLUSION

For small lesions in which there is no clear diagnosis of malignant melanoma, an initial close monitoring to document tumor growth does not impact visual prognosis, despite the potential complications associated with the untreated tumor. However, the survival should remain the main outcome of the treatment of these lesions.

Impact of HPV status in T1-2 oropharyngeal squamous cell carcinoma with bulky N3 nodes: a multicenter GETTEC study

PURPOSE

The purpose of our study was to investigate the impact of HPV status in oncologic outcomes in patients with T1-2 oropharyngeal SCC associated with bulky N3 nodes, and to determine progression prognosis factors aiming to define the best therapeutic strategies for these patients.

METHODS

This multicenter retrospective study included patients with T1-2 oropharyngeal SCC with N3 nodes treated between 2010 and 2015 in 8 French comprehensive cancer centers. HPV status was determined with P16 hyperexpression in immunohistochemistry. HPV-positive patients were separated into 2 groups according to the associated smoking history (HPV + T +) or not (HPV + T-). We compared the oncological outcomes of patients according to HPV-status and smoking history.

RESULTS

Of 67 patients with T1-2 N3 oropharyngeal SCC, 36 patients (53.7%) were HPV negative and 31 patients (46.3%) HPV positive. 2-year PFS was significantly better in HPV + T- group (p = 0.036). The risk of death or progression was significantly reduced in HPV + T- comparatively to HPV- (HR 0.25 95%CI [0.07; 0.89]). 2-year OS was significantly better in HPV + T- group than in the other two groups (p = 0.017).

CONCLUSION

In patients with T1-2 oropharyngeal SCC associated with bulky N3 nodes, HPV positive patients without smoking history had better OS and PFS than HPV positive patients with smoking history and HPV negative patients. Thus, HPV status is a significant prognostic factor for survival but this benefit is altered when smoking history is associated. N3 HPV positive patients with smoking history have to be classified as high-risk.

AIRO GORTEC consensus on postoperative radiotherapy (PORT) in low-intermediate risk early stages oral squamous cell cancers (OSCC)

Evidence on the efficacy of postoperative radiotherapy (PORT) in low-intermediate risk squamous cell carcinoma of the oral cavity (OSCC) remains inconclusive. Members of a task force from two national radio-oncology Associations (AIRO and GORTEC) defined 14 clinically relevant questions to identify "gray areas" pertinent to the indication for PORT in this clinical setting. Consequently, a literature review was performed on the topic. The resulting statements were then rated by an Expert Panel (EP) using a modified Delphi method. Only radiation oncologists were part of the discussion and voting on the scenarios. There was agreement on the 14 statements at the first round of voting. The task force then decided to propose clinical cases for the two more controversial statements that had received a lower agreement to better capture the Experts' attitudes. The clinical cases highlighted a more significant decisional heterogeneity. However, the good level of consensus reached among the two Associations gives relevant support in informing clinical choices while acknowledging general indications cannot fit all clinical situations and do not replace multidisciplinary discussion.

Immunotherapy and Modern Radiotherapy Technique for Older Patients with Locally Advanced Head and Neck Cancer: A Proposed Paradigm by the International Geriatric Radiotherapy Group

The standard of care for locally advanced head and neck cancer is concurrent chemoradiation or postoperative irradiation with or without chemotherapy. Surgery may not be an option for older patients (70 years old or above) due to multiple co-morbidities and frailty. Additionally, the standard chemotherapy of cisplatin may not be ideal for those patients due to oto- and nephrotoxicity. Though carboplatin is a reasonable alternative for cisplatin in patients with a pre-existing hearing deficit or renal dysfunction, its efficacy may be inferior to cisplatin for head and neck cancer. In addition, concurrent chemoradiation is frequently associated with grade 3-4 mucositis and hematologic toxicity leading to poor tolerance among older cancer patients. Thus, a new algorithm needs to be developed to provide optimal local control while minimizing toxicity for this vulnerable group of patients. Recently, immunotherapy with check point inhibitors (CPI) has attracted much attention due to the high prevalence of program death-ligand 1 (PD-L1) in head and neck cancer. In patients with recurrent or metastatic head and neck cancer refractory to cisplatin-based chemotherapy, CPI has proven to be superior to conventional chemotherapy for salvage. Those with a high PD-L1 expression defined as 50% or above or a high tumor proportion score (TPS) may have an excellent response to CPI. This selected group of patients may be candidates for CPI combined with modern radiotherapy techniques, such as intensity-modulated image-guided radiotherapy (IM-IGRT), volumetric arc therapy (VMAT) or proton therapy if available, which allow for the sparing of critical structures, such as the salivary glands, oral cavity, cochlea, larynx and pharyngeal muscles, to improve the patients' quality of life. In addition, normal organs that are frequently sensitive to immunotherapy, such as the thyroid and lungs, are spared with modern radiotherapy techniques. In fit or carefully selected frail patients, a hypofractionated schedule may be considered to reduce the need for daily transportation. We propose a protocol combining CPI and modern radiotherapy techniques for older patients with locally advanced head and neck cancer who are not eligible for cisplatin-based chemotherapy and have a high TPS. Prospective studies should be performed to verify this hypothesis.

Interdisciplinary challenges and aims of flap or graft reconstruction surgery of sinonasal cancers: What radiologists and radiation oncologists need to know

In sinonasal cancer surgery, a fundamental challenge is to understand the postoperative imaging changes after reconstruction. Misinterpretation of post-operative imaging may lead to a misdiagnosis of tumor recurrence. Because radiotherapy planning is based on imaging, there are many gaps in knowledge to be filled in the interpretation of postoperative imaging to properly define radiotherapy tumor volumes in the presence of flaps. On the other hand, radiotherapy may be responsible for tissue fibrosis or atrophy, the anatomy of the reconstructed region and the functional outcomes may change after radiotherapy compared to surgery alone. This narrative review illustrates the interdisciplinary aims and challenges of sinonasal reconstructive surgery using flaps or grafts. It is particularly relevant to radiologists and radiation oncologists, at a time when intensity modulated radiotherapy and proton therapy have the potential to further contribute to reduction of morbidity.

Reirradiation: A complex situation

Reirradiation of a tumor recurrence or second cancer in a previously irradiated area is challenging due to lack of high-quality physical, radiobiological, clinical data and inherent substantial risks of toxicity with cumulative dose and uncertain tissue recovery. Yet, major advances have been made in radiotherapy techniques, that have the potential to achieve cure while limiting severe toxicity rates, but still much research is necessary to better appraise the therapeutic index in such a complex situation.

[Radiation-induced retinopathy: actual knowledge and new concepts]

Radiation retinopathy is an occlusive vascular pathology following radiotherapy, generally targeted on the eye or peri-ocular structures. Despite increasingly precise techniques (stereotactic radiosurgery, proton therapy, etc.), the inclusion of the retina in the radiation field is sometimes unavoidable. This can lead to a severe pathology, which can ultimately cause blindness or even the anatomical loss of the eye when neovascular glaucoma occurs, due to the abnormal proliferation of neovessels. Radiation retinopathy have been described for more than a century, but it has recently seen great advances in both diagnosis and treatment. The advances of efficient and less invasive examinations in our clinical practice, such as OCT-angiography, allows for easier screening and diagnosis at earlier stages. Thus a new approach to the pathology is necessary, first of all through new definitions and classifications including previously undetected minimal forms. Furthermore, the recent appearance of intravitreal therapies by injection of anti-VEGF or dexamethasone implants has drastically changed the visual prognosis of these patients, who were previously treated only by retinal photocoagulation of the ischaemic areas. Recent studies have even shown the effectiveness of these new molecules in preventing the development of radiation retinopathy. This review of the literature provides an update on this disease and details how these recent diagnostic and therapeutic developments may play a role in the management of this complication.

30 years of ocular proton therapy, the Nice view

PURPOSE

Radiotherapy with protons (PT) is a standard treatment of ocular tumors. It achieves excellent tumor control, limited toxicities, and the preservation of important functional outcomes, such as vision. Although PT may appear as one homogenous technique, it can be performed using dedicated ocular passive scattering PT or, increasingly, Pencil Beam Scanning (PBS), both with various degrees of patient-oriented customization.

MATERAIAL AND METHODS

MEDICYC PT facility of Nice are detailed with respect to their technical, dosimetric, microdosimetric and radiobiological, patient and tumor-customization process of PT planning and delivery that are key. 6684 patients have been treated for ocular tumors (1991-2020). Machine characteristics (accelerator, beam line, beam monitoring) allow efficient proton extraction, high dose rate, sharp lateral and distal penumbrae, and limited stray radiation in comparison to beam energy reduction and subsequent straggling with high-energy PBS PT. Patient preparation before PT includes customized setup and image-guidance, CT-based planning, and ocular PT software modelling of the patient eye with integration of beam modifiers. Clinical reports have shown excellent tumor control rates (∼95%), vision preservation and limited toxicity rates (papillopathy, retinopathy, neovascular glaucoma, dry eye, madarosis, cataract).

RESULTS

Although demanding, dedicated ocular PT has proven its efficiency in achieving excellent tumor control, OAR sparing and patient radioprotection. It is therefore worth adaptations of the equipments and practice.

CONCLUSIONS

Some of these adaptations can be transferred to other PT centers and should be acknowledeged when using non-PT options.

Association Between Cardiac Radiation Exposure and the Risk of Arrhythmia in Breast Cancer Patients Treated With Radiotherapy: A Case–Control Study

Background

Previous studies suggested that radiation therapy (RT) for breast cancer (BC) can induce cardiac arrhythmias and conduction disorders. However, the association with mean heart dose and specific cardiac substructures doses was less studied.

Materials and Methods

We conducted a nested case–control study based on French BC patients, enrolled in the European MEDIRAD-BRACE study (https://clinicaltrials.gov, Identifier: NCT03211442), who underwent three-dimensional conformal radiation therapy (3D-CRT) between 2009 and 2013 and were retrospectively followed until 2019. Cases were incident cases of cardiac arrhythmia. Controls without arrhythmia were selected with propensity-scored matching by age, duration of follow-up, chemotherapy, hypertension, and diabetes (ratio 1:4 or 5). Doses to the whole heart (WH), left and right atria (LA and RA), and left and right ventricles (LV and RV) were obtained after delineation with multi-atlas-based automatic segmentation.

Results

The study included 116 patients (21 cases and 95 controls). Mean age at RT was 64 ± 10 years, mean follow-up was 7.0 ± 1.3 years, and mean interval from RT to arrhythmia was 4.3 ± 2.1 years. None of the results on association between arrhythmia and cardiac doses reached statistical significance. However, the proportion of right-sided BC was higher among patients with arrhythmia than among controls (57% vs. 51%, OR = 1.18, p = 0.73). Neither mean WH dose, nor LV, RV, and LA doses were associated with an increased risk of arrhythmia (OR = 1.00, p > 0.90). In contrast, the RA dose was slightly higher for cases compared to controls [interquartile range (0.61–1.46 Gy) vs. (0.49–1.31 Gy), p = 0.44], and a non-significant trend toward a potentially higher risk of arrhythmia with increasing RA dose was observed (OR = 1.19, p = 0.60). Subanalysis according to BC laterality showed that the association with RA dose was reinforced specifically for left-sided BC (OR = 1.76, p = 0.75), while for right-sided BC, the ratio of mean RA/WH doses may better predict arrhythmia (OR = 2.39, p = 0.35).

Conclusion

Despite non-significant results, our exploratory investigation on BC patients treated with RT is the first study to suggest that right-sided BC patients and the right atrium irradiation may require special attention regarding the risk of cardiac arrhythmia and conduction disorders. Further studies are needed to expand on this topic.

Ocular proton therapy, pencil beam scanning high energy proton therapy or stereotactic radiotherapy for uveal melanoma; an in silico study

PURPOSE

In radiotherapy, the dose and volumes of the irradiated normal tissues is correlated to the complication rate. We assessed the performances of low-energy proton therapy (ocular PT) with eye-dedicated equipment, high energy PT with pencil-beam scanning (PBS) or CyberKnife^R  -based stereotactic irradiation (SBRT).

MATERIAL AND METHODS

CT-based comparative dose distribution between external beam radiotherapy techniques was assessed using an anthropomorphic head phantom. The prescribed dose was 60Gy_RBE in 4 fractions to a typical posterior pole uveal melanoma. Clinically relevant structures were delineated, and doses were calculated using radiotherapy treatment planning softwares and measured using Gafchromic dosimetry films inserted at the ocular level.

RESULTS

Precision was significantly better with ocular PT than both PBS or SBRT in terms of beam penumbra (80%-20%: laterally 1.4 vs. ≥10mm, distally 0.8 vs. ≥2.5mm). Ocular PT duration was shorter, allowing eye gating and lid sparing more easily. Tumor was excellent with all modalities, but ocular PT resulted in more homogenous and conformal dose compared to PBS or SBRT. The maximal dose to ocular/orbital structures at risk was smaller and often null with ocular PT compared to other modalities. Mean dose to ocular/orbital structures was also lower with ocular PT. Structures like the lids and lacrimal punctum could be preserved with ocular PT using gaze orientation and lid retractors, which is easier to implement clinically than with the other modalities. The dose to distant organs was null with ocular PT and PBS, in contrast to SBRT.

CONCLUSIONS

ocular PT showed significantly improved beam penumbra, shorter treatment delivery time, better dose homogeneity, and reduced maximal/mean doses to critical ocular structures compared with other current external beam radiation modalities. Similar comparisons may be warranted for other tumor presentations.

Impact of radiotherapy on survival in resected or unresectable anaplastic thyroid carcinomas, a Rare Cancer Network study

PURPOSE

Anaplastic thyroid carcinomas (ATC) are a heterogenous group of tumors of overall dismal prognosis. We designed models to identify relevant prognostic factors of survival of irradiated ATC patients including radiotherapy modalities (field size, dose).

MATERIAL AND METHODS

Between 2000 and 2017, 166 ATC patients' treatments were divided into surgery and postoperative radiotherapy (poRT) or definitive radiotherapy (RT). Multiple imputation approach was used for missing data. Prognostic factors were identified using Lasso-penalized Cox modelling and predicted risk scores were built.

RESULTS

Patients undergoing RT (n=70) had more adverse patient and disease characteristics than those undergoing poRT (n=96). Corresponding median survival rates were 5.4 and 12.1 months, respectively. PoRT patients undergoing poRT more likely received extended-field radiotherapy with prophylactic nodal irradiation, but rather received platinum- vs. adriamycin-based chemoradiotherapy. Radiotherapy was conventionally fractionated, delivered >60Gy in 51.9% and 61.7% and used extended fields in 88.5% and 71.2% of patients with poRT or RT. Radiotherapy interruption rates for toxicity were similar in the two groups. The best poRT-group model identified age>45yo, PS≥1, pathologic tumor stage≥pT4b,>N1 and R2 resection as poor prognostic factors. The best RT-group model (C-index of 0.72) identified PS≥3,>N1 and extended-field radiotherapy with prophylactic nodal irradiation (as opposed to tumour-bed irradiation only) as poor prognostic factors.

CONCLUSION

In patients undergoing poRT, radiotherapy parameters had little influence over their survival irrespective of patient, disease characteristics, and quality of resection. In patients undergoing RT, extended-field radiotherapy improved survival in addition to PS and nodal stage.

Handling missing covariates in observational studies: An illustration with the assessment of prognostic factors of survival outcomes in sarcoma in irradiated fields (SIF)

11558

Background: Missing covariates are common in observational research. They can result in biased estimations and loss of power to detect associations. Limited data regarding prognostic factors of survival outcomes of SIF are available. We assessed prognostic factors of overall (OS), progression-free (PFS) and metastatic- progression-free (MPFS) survivals in SIF using 3 methods to account for missing covariates. Methods: We relied on the NETSARC database of the French Sarcoma Group: Cox models for OS/PFS and competitive hazard survival models for MPFS. Prognostic factors investigated were age, sex, tumor characteristics (histology, size, depth, grade), metastasis, surgery, surgical resection, expertise of the surgeon (NETSARC/other), pre-surgical imaging (Y/N) and neoadjuvant treatment. To account for missing covariates, we used multiple imputation (MI) by fully conditional specification (Bartlett 2015). The observed data are used to estimate the missing covariate and subsequently replace (impute) the missing value by that estimate. With the “missing-data modality” alternative approach, a category “missing” was created (e.g. yes/no/missing). With the “complete-case” alternative approach, analysis was restricted to patients with all covariates available. Results: Among the 504 patients, 169 had all covariates available (33%). Rate of missing data was greater than 20% for imaging, neoadjuvant treatment, and surgical resection. In the complete-case analysis (N = 169), factors associated with OS included R1/R2 (vs R0) surgical resection (p = 0.03). In opposite, MI (N = 504) revealed an association with metastasis (p = 0.03), and a time-varying effect for surgical resection (p < 0.001), with a risk increasing over time for R1/R2 vs R0). For PFS and MI, associated factors included higher grade and ungradable tumors (p = 0.002) and R1/R2 vs R0 resection (p < 0.001), not found with the complete-case analysis. For MPFS and MI, factors included metastasis (p = 0.03), higher grade tumor (p = 0.007) and R1/R2 resection (p = 0.001). Grade and resection were not found in the complete-case analysis. The missing-data modality led to slight differences with MI, including significant association due to missing covariate (e.g. tumors with size missing associated with shorter PFS). Conclusions: We identified prognostic factors of survival outcomes for SIF. The complete-case analysis led to reduced statistical power and population was non-representative of the full sample, introducing bias. In non-randomized studies, as the outcome may be related to variables with missing values, the missing-data modality method will typically result in biased estimates. Appropriate statistical methods for missing covariates, such as MI, should be considered in particular for observational studies.

International assessment of interobserver reproducibility of flap delineation in head and neck carcinoma

Background: Several reports have suggested that radiotherapy after reconstructive surgery for head and neck cancer (HNC), could have deleterious effects on the flaps with respect to functional outcomes. To predict and prevent toxicities, flap delineation should be accurate and reproducible. The objective of the present study was to evaluate the interobserver variability of frequent types of flaps used in HNC, based on the recent GORTEC atlas.Materials and methods: Each member of an international working group (WG) consisting of 14 experts delineated the flaps on a CT set from six patients. Each patient had one of the five most commonly used flaps in HNC: a regional pedicled pectoralis major myocutaneous flap, a local pedicled rotational soft tissue facial artery musculo-mucosal (FAMM) (2 patients), a fasciocutaneous radial forearm free flap, a soft tissue anterolateral thigh (ALT) free flap, or a fibular free flap. The WG's contours were compared to a reference contour, validated by a surgeon and a radiologist specializing in HNC. Contours were considered as reproducible if the median Dice Similarity Coefficient (DSC) was > 0.7.Results: The median volumes of the six flaps delineated by the WG were close to the reference contour value, with approximately 50 cc for the pectoral, fibula, and ALT flaps, 20 cc for the radial forearm, and up to 10 cc for the FAMM. The volumetric ratio was thus close to the optimal value of 100% for all flaps. The median DSC obtained by the WG compared to the reference for the pectoralis flap, the FAMM, the radial forearm flap, ALT flap, and the fibular flap were 0.82, 0.40, 0.76, 0.81, and 0.76, respectively.Conclusions: This study showed that the delineation of four main flaps used for HNC was reproducible. The delineation of the FAMM, however, requires close cooperation between radiologist, surgeon and radiation oncologist because of the poor visibility of this flap on CT and its small size.

A Patient Selection Approach Based on NTCP Models and DVH Parameters for Definitive Proton Therapy in Locally Advanced Sinonasal Cancer Patients

(1) Background: In this work, we aim to provide selection criteria based on normal tissue complication probability (NTCP) models and additional explanatory dose-volume histogram parameters suitable for identifying locally advanced sinonasal cancer patients with orbital invasion benefitting from proton therapy. (2) Methods: Twenty-two patients were enrolled, and two advanced radiation techniques were compared: intensity modulated proton therapy (IMPT) and photon volumetric modulated arc therapy (VMAT). Plans were optimized with a simultaneous integrated boost modality: 70 and 56 Gy(RBE) in 35 fractions were prescribed to the high risk/low risk CTV. Several endpoints were investigated, classified for their severity and used as discriminating paradigms. In particular, when NTCP models were already available, a first selection criterion based on the delta-NTCP was adopted. Additionally, an overall analysis in terms of DVH parameters was performed. Furthermore, a second selection criterion based on a weighted sum of the ΔNTCP and ΔDVH was adopted. (3) Results: Four patients out of 22 (18.2%) were suitable for IMPT due to ΔNTCP > 3% for at least one severe toxicity, 4 (18.2%) due to ΔNTCP > 20% for at least three concurrent intermediate toxicities and 16 (72.7%) due to the mixed sum of ΔNTCP and ΔDVH criterion. Since, for some cases, both criteria were contemporary fulfilled, globally 17/22 patients (77.3%) would benefit from IMPT. (4) Conclusions: For this rare clinical scenario, the use of a strategy including DVH parameters and NTCPs when comparing VMAT and IMPT is feasible. We showed that patients affected by sinonasal cancer could profit from IMPT compared to VMAT in terms of optical and central nervous system organs at risk sparing.

Correction: Brochet et al. A Quantitative Comparison between Shannon and Tsallis–Havrda–Charvat Entropies Applied to Cancer Outcome Prediction. Entropy 2022, 24, 436

Alexandre Huat, Sébastien Thureau, David Pasquier, Isabelle Gardin, Romain Modzelewski, David Gibon, Juliette Thariat and Vincent Grégoire were not included as authors in the original publication [...]

Dental management in head and neck cancers: from intensity-modulated radiotherapy with photons to proton therapy

INTRODUCTION

Despite reduction of xerostomia with intensity-modulated compared to conformal X-ray radiotherapy, radiation-induced dental complications continue to occur. Proton therapy is promising in head and neck cancers to further reduce radiation-induced side-effects, but the optimal dental management has not been defined.

MATERIAL AND METHODS

Dental management before proton therapy was assessed compared to intensity-modulated radiotherapy based on a bicentric experience, a literature review and illustrative cases.

RESULTS

Preserved teeth frequently contain metallic dental restorations (amalgams, crowns, implants). Metals blur CT images, introducing errors in tumour and organ contour during radiotherapy planning. Due to their physical interactions with matter, protons are more sensitive than photons to tissue composition. The composition of restorative materials is rarely documented during radiotherapy planning, introducing dose errors. Manual artefact recontouring, metal artefact-reduction CT algorithms, dual or multi-energy CT and appropriate dose calculation algorithms insufficiently compensate for contour and dose errors during proton therapy. Physical uncertainties may be associated with lower tumour control probability and more side-effects after proton therapy. Metal-induced errors should be quantified and removal of metal restorations discussed on a case by case basis between dental care specialists, radiation oncologists and physicists. Metallic amalgams can be replaced with water-equivalent materials and crowns temporarily removed depending on rehabilitation potential, dental condition and cost. Implants might contraindicate proton therapy if they are in the proton beam path.

CONCLUSION

Metallic restorations may more severely affect proton than photon radiotherapy quality. Personalized dental care prior to proton therapy requires multidisciplinary assessment of metal-induced errors before choice of conservation/removal of dental metals and optimal radiotherapy.

A Quantitative Comparison between Shannon and Tsallis–Havrda–Charvat Entropies Applied to Cancer Outcome Prediction

In this paper, we propose to quantitatively compare loss functions based on parameterized Tsallis–Havrda–Charvat entropy and classical Shannon entropy for the training of a deep network in the case of small datasets which are usually encountered in medical applications. Shannon cross-entropy is widely used as a loss function for most neural networks applied to the segmentation, classification and detection of images. Shannon entropy is a particular case of Tsallis–Havrda–Charvat entropy. In this work, we compare these two entropies through a medical application for predicting recurrence in patients with head–neck and lung cancers after treatment. Based on both CT images and patient information, a multitask deep neural network is proposed to perform a recurrence prediction task using cross-entropy as a loss function and an image reconstruction task. Tsallis–Havrda–Charvat cross-entropy is a parameterized cross-entropy with the parameter α. Shannon entropy is a particular case of Tsallis–Havrda–Charvat entropy for α=1. The influence of this parameter on the final prediction results is studied. In this paper, the experiments are conducted on two datasets including in total 580 patients, of whom 434 suffered from head–neck cancers and 146 from lung cancers. The results show that Tsallis–Havrda–Charvat entropy can achieve better performance in terms of prediction accuracy with some values of α.

Quality of life and financial toxicity after (chemo)radiation therapy in head and neck cancer: are there any sex- or gender-related differences?

The purpose of this article is to discuss the published evidence related to quality of life (QoL) and financial toxicity (FT) differences between female and male head and neck cancer patients treated with (chemo)radiotherapy. There is a need of promoting methods for assessing QoL difference between female and male patients in order to set up early rehabilitation, psychosocial care, and lifestyle interventions, as well as setting up specific interventions for minimizing financial stress.

Non-Cancer Effects following Ionizing Irradiation Involving the Eye and Orbit

Simple Summary

The irradiation of tumors involving the eye or orbit represents a complex therapeutic challenge due to the proximity between the tumor and organs that are susceptible to radiation. The challenges include tumor control, as it is often a surrogate for survival; organ (usually the eyeball) preservation; and the minimization of damage of sensitive tissues surrounding the tumor in order to preserve vision. Anticipation of the spectrum and severity of radiation-induced complications is crucial to the decision of which technique to use for a given tumor. The aim of the present review is to report the non-cancer effects that may occur following ionizing irradiation involving the eye and orbit and their specific patterns of toxicity for a given radiotherapy modality. The pros and cons of conventional and advanced forms of radiation techniques and their clinical implementation are provided with a clinical perspective.

Abstract

The eye is an exemplarily challenging organ to treat when considering ocular tumors. It is at the crossroads of several major aims in oncology: tumor control, organ preservation, and functional outcomes including vision and quality of life. The proximity between the tumor and organs that are susceptible to radiation damage explain these challenges. Given a high enough dose of radiation, virtually any cancer will be destroyed with radiotherapy. Yet, the doses inevitably absorbed by normal tissues may lead to complications, the likelihood of which increases with the radiation dose and volume of normal tissues irradiated. Precision radiotherapy allows personalized decision-making algorithms based on patient and tumor characteristics by exploiting the full knowledge of the physics, radiobiology, and the modifications made to the radiotherapy equipment to adapt to the various ocular tumors. Anticipation of the spectrum and severity of radiation-induced complications is crucial to the decision of which technique to use for a given tumor. Radiation can damage the lacrimal gland, eyelashes/eyelids, cornea, lens, macula/retina, optic nerves and chiasma, each having specific dose–response characteristics. The present review is a report of non-cancer effects that may occur following ionizing irradiation involving the eye and orbit and their specific patterns of toxicity for a given radiotherapy modality.

Risk of pacemaker implantation after radiotherapy for breast cancer: A study based on French nationwide health care database sample

Background

Among cardiac complications of breast cancer radiotherapy (BC RT), there are very limited data on arrhythmia and conduction disorders, in particular severe cases requiring permanent pacemaker implantation (PPMI). Therefore, this exploratory study aimed to evaluate the risk of PPMI for BC patients treated with RT, compared with the general population and with BC patients not treated with RT.

Methods

The study was performed on a 1/97 representative sample of the French health care database (EGB database). Adult women with a first BC treated with or without RT between 2008 and 2016 were included, followed until 2018, and de novo PPMI were identified. We compared the PPMI incidence in BC cohort relative to the general population with standardized incidence ratio (SIR) and evaluated the risk of PPMI in RT patients compared to patients without RT with a competing risk survival analysis.

Results

A total of 3853 BCE patients were included. Among BC patients treated with RT, 28 PPMI cases were observed compared with 13 expected cases, corresponding to a SIR of 2.18 [95% CI: 1.45-3.06]. For BC patients not treated with RT, the SIR was 1.01 [95% CI: 0.40-1.90]. Patients treated with RT showed a borderline significant higher risk of PPMI compared with those not treated with RT (subdistribution Hazard Ratio = 2.08, 95% CI 0.87-4.97, p = 0.09).

Conclusions

Our exploratory findings indicate that, over the last decade in France, BC patients treated with RT appeared to be at higher risk of PPMI than general population. Further studies are needed to expand on this topic.

[Sinonasal cancers]

Sinonasal cancers. Sinonasal cancers (SNC) belong to the spectrum of rare tumors, with respect to other tumors of the head and neck and intrinsically by the multiple histological entities that they cover. It is important to raise awareness among physicians about the diagnostic and therapeutic elements of SNC, as well as their functional consequences, so that these patients are better diagnosed and monitored during and following specific oncological treatment. We also shed light on the various histological entities and new therapeutic options, in particular endoscopic surgery, conformational radiotherapy and systemic treatments. Finally, we underline the importance of the REFCOR network of expertise, which makes it possible to offer optimal management of these rare tumors, and of the CORASSO association, which provides patients a major additional extra-medical support.

Conformal radiotherapy in management of soft tissue sarcoma in adults

We present the update of the recommendations of the French society of radiation oncology on soft tissue sarcomas. Currently, the initial management of sarcomas is very important as it may impact on patients' quality of life, especially in limb soft tissue sarcomas, and on overall survival in trunk sarcomas. Radiotherapy has to be discussed within a multidisciplinary board meeting with results of biopsy, eventually reexamined by a dedicated sarcoma pathologist. The role of radiotherapy varies according to localization of soft tissue sarcoma. It is part of the standard treatment in grade 2 and 3 sarcomas of the extremities and superficial trunk>5cm. In case of R1 or R2 resection, reexcision should be discussed. In such cases, it may be delivered preoperatively (50Gy/25 fractions of 2Gy) or postoperatively. In retroperitoneal sarcomas, preoperative conformal radiotherapy with or without modulated intensity cannot be proposed systematically in daily practice. Concomitant chemoradiotherapy cannot be considered a standard treatment. Intensity-modulated radiotherapy has become widely available. Other soft tissue sarcoma sites such as trunk, head and neck and gynaecological soft tissue sarcomas will be addressed, as well as other techniques that may be used such as brachytherapy and proton therapy.

The Impact of Resampling and Denoising Deep Learning Algorithms on Radiomics in Brain Metastases MRI

Simple Summary

Due to the central role of magnetic resonance Imaging (MRI) in the management of patients with cancer, waiting lists exceed clinically relevant delays. For this reason, many research groups and MRI manufacturers develop algorithms as resampling and denoising models to allow faster acquisition time without deterioration in image quality. Whereas these algorithms are available in all new MRI, it is not clear how they will impact image features as well as the validity of statistical model of radiomics which use deep images characteristics to predict treatment outcome. The aim of this study was to develop resampling and denoising deep learning (DL) models and evaluate their impact on radiomics from post-Gd-T1w-MRI brain images with brain metastases. We show that resampling and denoising DL models reconstruct low resolution and noised MRI images acquired quickly into high quality images. While fast acquisition loses most of the radiomic-features and invalidates predictive radiomic models, DL models restore these parameters.

Abstract

Background: Magnetic resonance imaging (MRI) is predominant in the therapeutic management of cancer patients, unfortunately, patients have to wait a long time to get an appointment for examination. Therefore, new MRI devices include deep-learning (DL) solutions to save acquisition time. However, the impact of these algorithms on intensity and texture parameters has been poorly studied. The aim of this study was to evaluate the impact of resampling and denoising DL models on radiomics. Methods: Resampling and denoising DL model was developed on 14,243 T1 brain images from 1.5T-MRI. Radiomics were extracted from 40 brain metastases from 11 patients (2049 images). A total of 104 texture features of DL images were compared to original images with paired t-test, Pearson correlation and concordance-correlation-coefficient (CCC). Results: When two times shorter image acquisition shows strong disparities with the originals concerning the radiomics, with significant differences and loss of correlation of 79.81% and 48.08%, respectively. Interestingly, DL models restore textures with 46.15% of unstable parameters and 25.96% of low CCC and without difference for the first-order intensity parameters. Conclusions: Resampling and denoising DL models reconstruct low resolution and noised MRI images acquired quickly into high quality images. While fast MRI acquisition loses most of the radiomic features, DL models restore these parameters.

Radiotherapy for oral cavity cancers

Intensity modulated radiation therapy and brachytherapy are standard techniques of irradiation for the treatment of oral cavity cancers. These techniques are detailed in terms of indication, planning, delineation and selection of the volumes of interest, dosimetry and patients positioning control. This is an update of the guidelines of the French Society of Radiotherapy Correspondence.

Radiotherapy of salivary gland tumours

Primary tumours of the salivary glands account for about 5 to 10% of tumours of the head and neck. These tumours represent a multitude of situations and histologies, where surgery is the mainstay of treatment and radiotherapy is frequently needed for malignant tumours (in case of stage T3-T4, nodal involvement, extraparotid invasion, positive or close resection margins, histological high-grade tumour, lymphovascular or perineural invasion, bone involvement postoperatively, or unresectable tumours). The diagnosis relies on anatomic and functional MRI and ultrasound-guided fine-needle aspiration for the diagnostic of benign or malignant tumors. In addition to patient characteristics, the determination of primary and nodal target volumes depends on tumor extensions and stage, histology and grade. Therefore, radiotherapy of salivary gland tumors requires a certain degree of personalization, which has been codified in the recommendations of the French multidisciplinary network of expertise for rare ENT cancers (Refcor) and may justify a specialised multidisciplinary discussion. Although radiotherapy is usually recommended for malignant tumours only, recurrent pleomorphic adenomas may sometimes require radiotherapy based on multidisciplinary discussion. An update of indications and recommendations for radiotherapy for salivary gland tumours in terms of techniques, doses, target volumes and dose constraints to organs at risk of the French society for radiotherapy and oncology (SFRO) was reported in this article.

Radiotherapy for hypopharynx cancers

We present the update of the recommendations of the French society of oncological radiotherapy on radiotherapy for hypopharynx. Intensity-modulated radiotherapy is the gold standard treatment for hypopharynx cancers. Early T1 and T2 tumors could be treated by exclusive radiotherapy or surgery followed by postoperative radiotherapy in case of high recurrence risk. For locally advanced tumours requiring total pharyngolaryngectomy (T2 or T3) or with significant lymph nodes involvement, induction chemotherapy followed by exclusive radiotherapy or concurrent chemoradiotherapy were possible. For T4 tumour, surgery must be proposed. The treatment of lymph nodes is based on initial primary tumour treatment. In non-surgical procedure, for 35 fractions, curative dose is 70Gy (2Gy per fraction) and prophylactic dose are 50 to 56Gy (2Gy per fraction in case of sequential radiotherapy or 1.6Gy in case of integrated simultaneous boost) radiotherapy; for 33 fractions, curative dose is 69.96Gy (2.12Gy per fraction) and prophylactic dose is 52.8Gy (1.6Gy per fraction in integrated simultaneous boost radiotherapy or 54Gy in 1.64Gy per fraction); for 30 fractions, curative dose is 66Gy (2.2Gy per fraction) and prophylactic dose is 54Gy (1.8Gy per fraction in integrated simultaneous boost radiotherapy). Doses over 2Gy per fraction could be done when chemotherapy is not used regarding potential larynx toxicity. Postoperatively, radiotherapy is used in locally advanced cancer with dose levels based on pathologic criteria, 60 to 66Gy for R1 resection and 54 to 60Gy for complete resection in bed tumour; 50 to 66Gy in lymph nodes areas regarding extracapsular spread. Volume delineation were based on guidelines cited in this article.

Stereotactic Body Radiation Therapy for Oligometastatic Breast Cancer: A Retrospective Multicenter Study

INTRODUCTION

Stereotactic radiotherapy may improve the prognosis of oligometastatic patients. In the literature, there is very little data available that is specific to breast cancer.

MATERIALS AND METHODS

We conducted a multicenter retrospective study. The primary objective was to estimate progression-free survival after stereotactic body radiotherapy (SBRT) using Cyberknife of breast cancer oligometastases. The secondary objectives were to estimate overall survival, local control, and toxicity. The inclusion criteria were oligometastatic breast cancer with a maximum of five lesions distributed in one to three different organs, diagnosed on PET/CT and/or MRI, excluding brain metastases and oligoprogressions. This was combined with systemic medical treatment.

FINDINGS

Forty-four patients were enrolled from 2007 to 2017, at three high-volume cancer centers. The patients mostly had one to two lesion(s) whose most widely represented site was bone (24 lesions or 44.4%), particularly in the spine, followed by liver (22 lesions or 40.7%), then pulmonary lesions (six lesions or 11.1%). The primary tumor expressed estrogen receptors in 33 patients (84.6%); the status was HER2+++ in 7 patients (17.9%). The median dose was 40 Gy (min-max: 15-54) prescribed at 80% isodose, the median number of sessions was three (min-max: 3-10). The median D50% was 42 Gy (min max 17-59). After a median follow-up of 3.4 years, progression-free survival (PFS) at one year, two years, and three years was 81% (95% CI: 66-90%), 58% (95% CI: 41-72%), and 45% (95% CI: 28-60%), respectively. The median PFS was 2.6 years (95% CI: 1.3 - 4.9). Overall survival at three years was 81% (95% CI: 63-90%). The local control rate at two and three years was 100%. Three patients (7.3%) experienced G2 acute toxicity, no grade ≥3 toxicity was reported.

CONCLUSION

The PFS of oligometastatic breast cancer patients treated with SBRT appears long, with low toxicity. Local control is high. SBRT for oligometastases is rarely applied in breast cancer in light of the population in our study. Phase III studies are ongoing.

Breast cancer radiotherapy and risk of pacemaker implantation: an epidemiologic analysis using the French nationwide claims database

Background

Radiotherapy (RT) is a major treatment for breast cancer (BC), but it is also associated with an increased long-term (&gt;5–10 years) risk of cardiac complications. Specific data on cardiac arrhythmias and conduction disorders are warranted.

Purpose

To evaluate whether pacemaker (PM) implantation risk is higher in BC patients treated with RT compared to the general population or population of BC patients treated without RT.

Methods

Our study was based on the Echantillon Généraliste de Bénéficiaires (EGB), the 1/97 random sample of the French nationwide health insurance claims database. The population of patients treated for BC consisted of adult women with a first BC identified by the ICD-10 diagnosis codes between 2008 and 2016, and followed through 2018. PM implantations and RT were identified with medical procedures codes in the french Common Classification of Medical Procedures (CCAM). For each year from 2008 to 2018, the reference population included all adult women of the EGB database. History of PM or BC was an exclusion criteria. Annual incidence rates of PM implantations were evaluated between 2008 and 2018 in the reference populations. The number of PM cases observed in BC patients at least one year after BC diagnosis was compared with the expected number of PM cases calculated by using reference incidence rates with age standardization. We then computed the standardized incidence ratio (SIR) as the ratio of the observed number of PM to the expected number of PM, with 95% confidence intervals (CIs). Thereafter, a survival analysis was performed in BC patients using a Cox regression model (Hazard Ratio – HR) in order to evaluate the risk of PM associated with treatment including RT (RT) compared with treatment not including RT (no RT).

Results

A total of 3,853 patients were included in the population of patients treated for BC between 2008 and 2016 with a mean age of 60 years old and a mean follow-up of 5.6 years. In this population, 35 cases of PM were observed, compared with 19.9 expected cases of PM, corresponding to a significant SIR=1.76 (95% CI: 1.22 - 2.39). This excess risk was carried by the RT group of 2973 patients (77% of BC population): 28 observed PM vs 12.9 expected, SIR=2.18 (95% CI: 1.45–3.06). In Cox regression analysis, after adjustment on age, RT was associated with an increased risk of PM compared with no RT, but this result did not reach statistical significance (HR=1.73; p-value=0.21).

Conclusion

Based on our study, BC patients receiving RT appeared to be at higher risk of PM implantation than general female population and BC patients without RT, illustrating a potential association between cardiac exposure during BC RT and conduction disorders.

Funding Acknowledgement

Type of funding sources: None.

A priori quality assurance using a benchmark case of the randomized phase 2 GORTEC 2014-14 in oligometastatic head and neck cancer patients

PURPOSE

A Benchmark Case (BC) was performed as part of the quality assurance process of the randomized phase 2 GORTEC 2014-14 OMET study, testing the possibility of multisite stereotactic radiation therapy (SBRT) alone in oligometastatic head and neck squamous cell carcinoma (HNSCC) as an alternative to systemic treatment and SBRT.

MATERIAL AND METHODS

Compliance of the investigating centers with the prescription, delineation, planning and evaluation recommendations available in the research protocol was assessed. In addition, classical dosimetric analysis was supplemented by quantitative geometric analysis using conformation indices.

RESULTS

Twenty centers participated in the BC analysis. Among them, four major deviations (MaD) were reported in two centers. Two (10%) centers in MaD had omitted the satellite tumor nodule and secondarily validated after revision. Their respective DICE indexes were 0.37 and 0 and use of extracranial SBRT devices suboptimal There were significant residual heterogeneities between participating centers, including those with a similar SBRT equipment, with impact of plan quality using standard indicators and geometric indices.

CONCLUSION

A priori QA using a BC conditioning the participation of the clinical investigation centers showed deviations from good SBRT practice and led to the exclusion of one out of the twenty participating centers. The majority of centers have demonstrated rigorous compliance with the research protocol. The use of quality indexes adds a complementary approach to improve assessment of plan quality.

Head and neck proton therapy in France: A missed opportunity or a challenge in front of us?

Following major advances of the best of photon-techniques such as intensity-modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT) and, to arrive soon, magnetic resonance (MR)-linac radiotherapy, there are still substantial opportunities in the treatment of head and neck cancers to further reduce the toxicity burden. Proton therapy represents another attractive option in this high-quality and highly competitive precision radiotherapy landscape. Proton therapy holds promises to reduce toxicities and to escalate the dose in radioresistant cases or cases where dose distribution is not satisfactory with photons. However, the selection of patients for proton therapy needs to be done using evidence-based medicine to build arguments in favor of personalized precision radiation therapy. Referral to proton therapy versus IMRT or SBRT should be registered (ProtonShare® platform) and envisioned in a formalized clinical research perspective through randomized trials. The use of an enrichment process using a model-based approach should be done to only randomize patients doomed to benefit from proton. To tackle such great opportunities, the French proton therapy challenge is to collaborate at the national and international levels, and to demonstrate that the extra-costs of treatment are worth clinically and economically in the short, mid, and long-term. In parallel to the clinical developments, there are still preclinical issues to be tackled (e.g., proton FLASH, mini-beams, combination with immunotherapy), for which the French Radiotransnet network offers a unique platform. The current article provides a personal view of the challenges and opportunities with a focus on clinical research and randomized trial requirements as well as the needs for strong collaborations at the national and international levels for PT in squamous cell carcinomas of the head and neck to date.