Role of radiotherapy fractionation in head and neck cancers (MARCH): an updated meta-analysis

A review of histopathologic assessment for head and neck oncologists

GOAL OF REVIEW

With a deeper understanding of histopathologic assessment, head and neck oncology specialists (surgical oncologists, radiation oncologists, and medical oncologists) will be better equipped to address the increasing complexity encompassing head and neck cancer management.

INTRODUCTION

Histopathologic assessment of surgical specimens imparts crucial information that is essential for post-operative treatment planning and prognostication for patients with head and neck squamous cell carcinoma (HNSCC). Herein, we discuss the most current guidelines and recommendations to elucidate the clinically relevant histopathologic features in HNSCC. This review discusses the following pathology features: extranodal extension, margins, perineural invasion, histologic grade, dysplasia, depth of invasion, lymphovascular invasion, and other considerations such as p16 immunohistochemistry, HPV in situ hybridization and worst pattern of invasion.

DISCUSSION

Understanding histopathology in HNSCC is essential for accurate diagnosis, prognostication, understanding tumor behavior, and treatment management. This complexity of care has led to consensus guidelines from numerous authorities which this paper discusses and summarizes for readers.

CONCLUSION

The understanding of key histopathology elements in HNSCC will augment multidisciplinary discussions and improve patient care. The current variability in existing consensus guidelines highlights the need for improved standardization of histopathology reporting in HNSCC. Standardization will enhance diagnostic accuracy, guide clinical decision-making, and facilitate the development of more effective treatment strategies.

Outcomes following IMRT alone in head and neck squamous cell carcinoma ordinarily managed with concurrent chemo-radiotherapy

PURPOSE/OBJECTIVE(S)

We report outcomes following IMRT-alone in patients with head-and-neck squamous cell carcinoma (HNSCC) ordinarily managed with concurrent chemo-radiotherapy.

MATERIALS/METHODS

HNSCC (excluding T1-2 N0) patients treated with IMRT-alone from 2005 to 2019 were included and restaged according to TNM-8. Overall survival (OS) was stratified by TNM-8 stage subgroups within HPV-positive (HPV + ) and separately within HPV-negative (HPV-) HNSCC. Multivariable analysis (MVA) identified prognostic factors for OS.

RESULTS

A total of 460 patients with HPV + and 623 HPV- HNSCC were identified. Reasons for chemotherapy omission were: age > 70 years and/or frailty (n = 551, 51 %), cisplatin contraindication (n = 241, 22 %), patient' preference (n = 106, 10 %), and clinician's decision (n = 185, 17 %). IMRT was delivered mostly using altered-fractionation: moderately-accelerated (70 Gy/35 fractions [f]/6 weeks [w], 55 %), hypofractionated (60 Gy/25f/5w, 14 %), and hyperfractionated-accelerated (64 Gy/40f/4w, 25 %). Median follow-up was 5.0 years. Five-year OS for HPV + stage-I-single node, stage-I-multiple nodes, stage-II-T1-2 N2, stage-II-T3 N0-N2, and stage-III were 90 %, 79 %%, 80 %, 64 %, and 33 %, and for HPV- stage III, IVA, and IVB were 47 %, 27 %, and 13 %, respectively. MVA confirmed lower OS in HPV + stage-I-multiple nodes (p = 0.03), II-T3 N0-N2 and III (vs stage-I-single node) and HPV- stage IVA/IVB (vs III) (p < 0.01), and marginally lower OS in HPV + stage-II-T3 N0-2 (vs I-single node) (p = 0.07).

CONCLUSION

Altered fractionated IMRT-alone is a valid option for patients with HPV + stage I-single node HNSCC, and an acceptable alternative for elderly/frail or cisplatin ineligible patients with HPV + stage I-multiple nodes and T1-2 N2 HNSCC. Patients with HPV + T3-T4 or N3 and HPV- stage III/IV HNSCC had unsatisfactory OS, requiring further research into alternative options.

A systematic review and proportional meta-analysis of image-based pattern of loco-regional failure analyses outcomes in head and neck squamous cell carcinoma

BACKGROUND AND PURPOSE

The prognosis following loco-regional failure after primary radiotherapy (RT) for head and neck squamous cell carcinoma (HNSCC) is poor. The hypothesis that most failures occur as a consequence of tumor radioresistance, can be evaluated by proxy as the proportion of failures that occur in the high-dose region. Several studies have investigated possible reasons for treatment failure by an image-based pattern of failure analyses (POF), comparing the initial planning CT scan with a scan conducted upon failure. The aim of the present systematic review and meta-analysis was to evaluate the proportion of failures that occurred in the high-dose region of all analyzed failures.

MATERIALS AND METHODS

A systematic database search from 2000 to 2023, was performed for studies including results from image-based loco-regional POF, regardless of the method, after primary RT for HNSCC. Proportions of volumetrically in-field (opposed to marginal or outfield) failures, point of origin-based inside high-dose targets, or covered by curative doses for both the number of patients and the number of failure sites were analyzed in proportional meta-analyses. The review was registered at Prospero (CRD42023412545).

RESULTS

Out of 56 included studies, accumulated image-based POF results were available from 1,161 patients and 658 individual failure sites. The majority of patients had in-field failures in volumetric-based studies (84 % (95 % CI: 77;90)), inside failures in point of origin-based studies (82 % (95% CI:61;85)) or failures covered by 95 % of dose prescribed to CTV1 (84 % (95% CI:69;95)). A trend toward increasing proportions of non-high-dose failures in more recently treated patients was observed.

CONCLUSION

Most loco-regional failures for patients treated with primary RT for HNSCC are related to the high-dose volume. Therefore, a focus on biomarkers predicting individual tumor radiosensitivity is warranted to enable individualized treatment intensification to increase loco-regional control.

HYHOPE: A phase I study of de-intensified hypofractionated radiation therapy for human papillomavirus-associated oropharynx cancer

BACKGROUND

Various de-escalation strategies for human papillomavirus-associated oropharynx cancers are under investigation. We have incorporated hypofractionated radiotherapy (RT) in a phase I study to assess the tolerability of dose and volume de-intensified RT completed in 3 weeks with weekly cisplatin.

METHODS

Patients with favorable oropharynx cancer, defined as T1-3, N0-2, p16 positive, and ≤10 pack-years, were enrolled using a rolling 6 design with 46.5 Gy in 15 fractions as level 0 and 52 Gy in 20 fractions as level -1. The elective neck was restricted to the involved plus adjacent nodal levels. The primary endpoint was the maximum tolerated dose/fractionation (MTD) of hypofractionated RT. Additional patients were enrolled at the MTD on the dose expansion cohort. All patients received three weekly doses of cisplatin (40 mg/m2).

RESULTS

Six patients were treated on level 0 with no dose limiting toxicity, and thus 46.5 Gy in 15 fractions was deemed the MTD. On the dose expansion cohort, 18 additional patients were enrolled for a total of 24 patients. Acute grade 3 toxicity occurred in 7 (29%) patients including oral mucositis, dysphagia, and weight loss. One patient experienced an acute grade 4 toxicity of lymphopenia, which resolved with time. Late toxicity consisted of one grade 2 xerostomia and one grade 2 dysphagia, with no late grade 3+ toxicity. Mean (standard deviation) MD Anderson Dysphagia Inventory composite score at baseline, 3 and 12 months were 86.5 (13.7), 85.5 (11.3), and 89.4 (9.4), respectively. With a median follow-up of 26.6 months, the 2-year cumulative incidence of locoregional recurrence was 13.8% (95% confidence interval 3.2-32%).

CONCLUSION(S)

De-intensified hypofractionated RT with weekly cisplatin completed in 3 weeks is well-tolerated with excellent toxicity profile and patient-reported swallow function warranting further investigation to assess efficacy.

International consensus on laryngeal preservation strategies in laryngeal and hypopharyngeal cancer

This Policy Review summarises an expert Delphi consensus process on larynx-preservation treatments in patients affected by intermediate-to-advanced laryngeal or hypopharyngeal squamous cell carcinoma. The experts, who represented all perspectives involved in multidisciplinary management of these patients and included patient representatives, approved 137 consensus statements that cover several relevant areas in the field of larynx-preserving treatments. Statements are grouped in the following topics: granular indications for T2-T3 cancer, indications for T4a cancer, indications for salvage organ-preservation surgery after chemoradiation failure, laryngeal function at baseline, which comorbidities are contraindications and to what extent, organ preservation in older patients: selection criteria, post-treatment surveillance, prognostic and predictive factors, listening to the patient's preferences: tools and implementation, prehabilitation and rehabilitation protocols, and cost-effectiveness of different laryngeal preservation approaches. We present a high-level summary of the results of the consensus process, with detailed reference to the full list of statements and supporting literature.

Chemotherapy-free innovations in locally advanced head and neck cancer: a comprehensive review

The treatment of locally advanced head and neck squamous cell carcinoma (LA-HNSCC) has traditionally relied on a multimodal approach, combining surgery, radiation therapy (RT), and chemotherapy. While chemotherapy plays a critical role in improving cure rates and functional outcomes, its substantial toxicity remains a major concern, particularly in older patients. These challenges are especially relevant for those who are unfit for chemotherapy or decline conventional concurrent chemoradiotherapy (CCRT), highlighting the need for alternative therapeutic options. Many patients are at high risk for severe side effects, often preventing them from completing the full chemotherapy regimen. This review explores alternative strategies to definitive CCRT of carcinomas of the larynx, hypopharynx and oropharynx, aiming to optimize treatment outcomes while minimizing toxicity. We discuss altered fractionation strategies as a promising alternative to conventional RT, offering a balance between treatment efficacy and quality of life. Additionally, we examine emerging approaches, including the combining of targeted therapies, immunotherapy, hyperthermia, photodynamic therapy and nanoparticle-based treatments with RT, which provide alternative or complementary options to traditional therapies in the management of LA-HNSCC.

Definitive treatment in squamous cell carcinoma of head and neck: A retrospective analysis of chemoradiotherapy in a university hospital setting

OBJECTIVE

To evaluate toxicities, tumor control, Event-Free Survival (EFS) and Overall Survival (OS) of patients with locoregionally advanced Head and Neck Squamous Cell Carcinoma (HNSCC) treated with definitive platinum-based Chemoradiation (CTRT).

METHODS

A total of 233 patients underwent treatment with RT plus weekly or every three weeks Cisplatin (CDDP) or Carboplatin (Carbo). Toxicity and response to treatment were classified using conventional criteria. Kaplan-Meier, log-rank test, and Cox regression (univariate and multivariate) were used to assess patient survival.

RESULTS

Half of patients presented toxicities grade 3 or 4, with nausea/vomiting and nephrotoxicity being more common in RT and CDDP group and anemia and neutropenia in RT and Carbo group. Complete or partial response was observed in 75% of patients, and the distinct protocols did not alter the treatment response. Two-year EFS and OS probabilities were 43.3% and 66.0%, respectively. Active smoking, an ECOG score of 2 or higher, stage IV tumor, and treatment with RT and Carbo were independent prognostic factors for poorer outcomes. Patients of these groups had approximately double chance of relapse and progression to death compared to others.

CONCLUSION

Our data indicate definitive treatment with RT and CDDP as the best treatment for locoregionally advanced HNSCC treated in Brazilian public hospitals. However, prospective randomized studies are required to establish the ideal treatment for those patients.

LEVEL OF EVIDENCE: 3

Managing Patients with Head and Neck Cancer and Advanced Age or Comorbidities

The dominant treatment paradigm for locoregionally advanced head and neck squamous cell carcinoma (HNSCC) involves postoperative or definitive radiotherapy with concurrent cisplatin chemotherapy. Despite years of research investigating de-intensified treatment, cisplatin-based chemoradiotherapy remains the standard, yet it is associated with significant acute and chronic toxicity. However, due to shared risk factors, such as advanced age, and tobacco and alcohol use, patients with HNSCC frequently have comorbid illnesses that impact treatment tolerability, adding complexity to treatment-related decision-making. In addition, many patients have medical contraindications to cisplatin, requiring alternative treatment strategies. It is thus important to consider how well patients are likely to tolerate treatment, and how to adapt treatment in response to a patient's condition, when weighing treatment options. In this review, we aim to offer readers guidance in managing the elderly or comorbid patient with HNSCC, with particular attention to (i) approaching comorbidity and fragility assessment to make determinations on intensity of treatment, (ii) considering primary treatment modality (eg, surgery vs radiotherapy, chemo-radiotherapy vs radiotherapy alone) and (iii) choice of concurrent systemic therapy agent.

Hypofractionated Radiation Therapy in the Definitive Management of Head and Neck Cancer

The use of hypofractionated radiation therapy has increased among many cancers, although its use in head and neck cancers remains limited due to concerns regarding acute and late toxicities. Recent retrospective and prospective studies demonstrate the preliminary safety and efficacy of hypofractionation in the definitive, postoperative, and preoperative settings for head and neck treatment. This article seeks to comprehensively review the rationale and data for novel fractionation schemes in this disease site. We also provide practical clinical and dosimetric insights based on our institutional experiences with hypofractionation in head and neck cancers.

Postoperative hyperfractionated IMRT with weekly cisplatin for head and neck cancer: phase IIa trial

Postoperative chemoradiotherapy (POCRT) is the standard treatment for patients with head and neck squamous cell carcinoma (HNSCC) with high-risk features (positive microscopic margins and/or extranodal extensions). We hypothesized that dose escalation using hyperfractionation in intensity-modulated radiotherapy (HF-IMRT) improves POCRT outcomes; however, no prospective trial has assessed the feasibility of POCRT in HF. Therefore, we evaluated the feasibility of POCRT using HF-IMRT. HNSCC patients with positive microscopic margins and/or extranodal extension following surgery were included. HF-IMRT (73.6 Gy in 64 fractions twice daily) was administered along with cisplatin at 40 mg/m2 once a week for seven cycles during radiotherapy. The primary endpoint was the proportion of patients who completed treatment, which included the planned radiotherapy and the administration of ≥200 mg/m2 of cisplatin. Feasibility was defined as the proportion of patients who completed treatment >60% using a one-sided binomial test. Ten patients were registered between October 2021 and April 2023. One patient was excluded because of tumor recurrence before POCRT. The median follow-up time was 18.2 months, and the proportion of patients who completed treatment was 88.9%. The median total dose of cisplatin was 240 mg/m2. The percentage of patients with grade 3 acute non-hematological adverse events was 77.8%. No patient experienced grade 4 or higher acute adverse events or grade 3 or higher late adverse events. POCRT using HF-IMRT is feasible for achieving adequate cisplatin doses and safe radiotherapy in patients with HNSCC.

Predicting cisplatin tolerability in older adults with head and neck cancer - Insights for improved chemoradiation outcomes

PURPOSE

Cumulative cisplatin doses of ≥ 200 mg/m2 improve survival in adults with head-and-neck squamous cell carcinoma (HNSCC) undergoing chemoradiation, but many older adults with HNSCC cannot receive this prognostically relevant dose due to toxicities. This study aims to develop predictive models to assess the likelihood of older adults with HNSCC receiving ≥ 200 mg/m2 cisplatin during chemoradiation.

METHODS

366 patients from the SENIOR database, an international cohort of adults ≥ 65 years with HNSCC, received definitive chemoradiation with single-agent cisplatin and were analyzed. A Generalized Linear Model (GLM), Support Vector Machine (SVM), and Random Forest Model (RFM) were trained and compared for their performance in predicting a cumulative cisplatin dose of ≥ 200 mg/m2.

RESULTS

195 (53 %) patients achieved a cumulative cisplatin dose of ≥ 200 mg/m2. In the GLM, laryngeal carcinoma (β = 1.37, p = 0.01), tumoral p16 positivity (β = 0.69, p = 0.04), higher hemoglobin levels (β = 0.26, p = 0.002), elevated C-reactive protein (CRP) concentration (β = 0.02, p = 0.003), and increased estimated glomerular filtration rate (eGFR) (β = 0.02, p = 0.008) were associated with a higher probability of reaching ≥ 200 mg/m2 cisplatin. Hemoglobin, CRP, eGFR, and p16 status constituted the most important features in the SVM and RFM. AUC values for the GLM, SVM, and RFM were 0.70 (95 % CI, 0.67-0.73), 0.71 (95 % CI, 0.68-0.73), and 0.73 (95 % CI, 0.71-0.75), respectively.

CONCLUSIONS

We developed predictive models to support clinicians in identifying older adults with HNSCC capable of tolerating ≥ 200 mg/m2 cumulative cisplatin during chemoradiation. Once validated, these models could improve personalized treatments and enhance shared decision-making in older adults with HNSCC.

Treatment strategies in human papillomavirus-related advanced penile cancer

Penile cancer is a rare neoplasm with heterogeneous prevalence influenced by risk factors such as smoking, poor hygiene and human papillomavirus (HPV) infection. Southern Africa, South America and Southeast Asia have the highest incidence of this disease. Penile squamous cell carcinomas (PSCCs) account for the majority of instances of penile cancer, with HPV-related carcinogenesis implicated in up to half of them. Increases in PSCC incidence in industrialized nations parallel the rising high-risk HPV infection rates, particularly HPV-16. Early-stage, localized PSCC is often manageable, but treatment options in advanced disease remain limited, with poor survival outcomes. Emerging evidence suggests that HPV-positive PSCC might exhibit unique therapeutic responses, including increased sensitivity to radiotherapy and chemotherapy, as has been observed in HPV-driven head and neck squamous cell carcinoma. Results of studies in HPV-positive PSCC demonstrate improved responses to chemoradiotherapy and immunotherapy, underscoring the potential for tailored treatments and de-escalation. Additionally, incorporating immunotherapy with radiotherapy in HPV-driven PSCC might provide greater oncological benefits than standard chemotherapy. These observations suggest that treatment strategies for HPV-positive PSCC might benefit from de-escalated chemoradiotherapy regimens or immunotherapy incorporation, potentially optimizing efficacy while minimizing toxic effects. Furthermore, biomarkers such as tumour mutational burden, programmed cell death ligand 1 expression, and genetic alterations could be crucial for predicting treatment response. Comprehensive biomarker assessment and accurate HPV status determination are essential for developing patient-tailored therapeutic strategies. These data provide evidence of the potential benefits of individualized approaches based on tumour biology and biomarker profiles.

Comparison of White Light With Narrow Band Imaging Using Flexible Laryngoscopy for the Detection of Local Recurrences After (Chemo)Radiation for Pharyngeal or Laryngeal Cancer: A Randomised Controlled Trial

OBJECTIVES

Early detection of local recurrences in patients with head and neck squamous cell carcinoma (HNSCC) is crucial for long-term survival. Aim of this study was to compare white light (WL) imaging with narrow band imaging (NBI) during flexible laryngoscopy for detection of local recurrences and evaluate the effects on clinical outcome in patients with HNSCC treated with radiotherapy ± chemotherapy ((C)RT).

DESIGN

Prospective randomised controlled trial.

SETTING

Tertiary head and neck oncologic center.

PARTICIPANTS

257 patients without residual disease after (C)RT were randomised in a WL group (n = 120) or WL-NBI group (n = 137) and followed for 24 months.

MAIN OUTCOME MEASURES

Local recurrence rate and overall survival, disease-specific survival, disease-free survival and local recurrence-free survival were compared between both groups.

RESULTS

Detection rate of local recurrences was the same in both groups: 11.7% in WL-NBI and 10.0% in WL (p > 0.05). Overall survival (WL: 88.3%, WL-NBI: 87.6%), disease-specific survival (WL: 86.7%, NBI: 83.9%), disease-free survival (WL: 85.0%, WL-NBI: 83.2%) and local recurrence-free survival (WL: 90.0%, WL-NBI: 89.1%) showed no superiority in the WL-NBI group (p > 0.05).

CONCLUSIONS

Local recurrence rates are relatively low in the first 24 months after (C)RT for HNSCC. WL-NBI did not improve the detection of local recurrences nor the survival compared to WL.

TRIAL REGISTRATION

This randomised clinical trial was registered at the research register UMCG with the number 201500918.

Long term effectiveness of intraoperative radiotherapy given as a boost in adjuvant treatment for oral cavity cancers

The oral cancer treatment of choice is surgical excision with an organ preservation, if it is possible. Radiation therapy is commonly used as a postoperative treatment. Delivering radiation dose during surgery, defined as intraoperative radiotherapy (IORT), can be very useful especially in case of high risk of recurrence or where gross or macroscopic residual disease are present. The aim of this retrospective study is to evaluate the effectiveness of IORT combined with postoperative fractionated irradiation (EBRT) of patients with squamous cell carcinoma of the oral cavity. The study included 23 patients: IORT dose of 5-7.5 Gy was delivered using 50 kV X-rays generated by INTRABEAM™, combined with EBRT of 50-60 Gy in 25-30 fractions depending on presence of extracapsular invasion and narrow or positive surgical margins. Standard statistical tests were used. Median follow up was 64 months (range 8-222 months). The 5-year local tumour control was 92% and 82.5% in the 10-year follow-up. The 5-year overall survival (OS) was 56% and decreased to 45% during the next 5 years. There were no differences in the LTC, DFS and OS regarding sex, T-stage, grade and tumour localization, although a small group of analysed cases may raise some uncertainties. Acute side effects of combined IORT and EBRT were mild and no late complications occurred. The present study indicated that low-energy X-rays IORT combined with postoperative EBRT is a feasible and safe therapeutic modality which likely reduces a risk of locoregional recurrences.

Quality of Decision Making in Radiation Oncology

High-quality decision making in radiation oncology requires the careful consideration of multiple factors. In addition to the evidence-based indications for curative or palliative radiotherapy, this article explores how, in routine clinical practice, we also need to account for many other factors when making high-quality decisions. Foremost are patient-related factors, including preference, and the complex interplay between age, frailty and comorbidities, especially with an ageing cancer population. Whilst clinical practice guidelines inform our decisions, we need to account for their applicability in different patient groups and different resource settings. With particular reference to curative-intent radiotherapy, we explore decisions regarding dose fractionation schedules, use of newer radiotherapy technologies and multimodality treatment considerations that contribute to personalised patient-centred care.

The clinical utility of circulating human papillomavirus across squamous cell carcinomas

BACKGROUND AND PURPOSE

The similarities in biology, treatment regimens and outcome between the different human papillomavirus (HPV) associated squamous cell carcinomas (SCCs) allow for extrapolation of results generated from one SC tumor type to another. In HPV associated cancers, HPV is integrated into the tumor genome and can consequently be detected in the circulating fragments of the tumor DNA. Thus, measurement of HPV in the plasma is a surrogate for circulating tumor DNA (ctDNA) and holds promise as a clinically relevant biomarker in HPV associated cancers. With the present overview we aim to present the status of circulating HPV studies in SCCs, the clinical potential and the gaps of knowledge, with the overall aim to facilitate the next steps into clinically relevant prospective trials.

MATERIAL AND METHODS

We reviewed the literature and presented the data for each tumor type as well as analyses of the clinical utility across the SCC.

RESULTS AND INTERPRETATION

A total of 41 studies were identified in cervical, head and neck and anal SCC and we discuss the common signals from the results across the different tumor sites. Our results not only confirm the strong clinical potential but also emphasize an urgent need to coordinate studies to allow for relevant sample sizes and statistical validations.

Multicentric Cross-Sectional Survey to Assess the Variation of Fractionation Strategies Used in the Management of Head and Neck Cancers in the Asian Region (INNOCENCE-ASIA)

PURPOSE

Head and neck cancers (HNCs) are in general treated with conventional fractionation regimen of 1.8-2 Gy per fraction. Altered fractionation (ALFT) strategies such as hypofractionation radiotherapy (HYPO-RT), accelerated fractionation radiotherapy (AFRT), and hyperfractionation radiotherapy (HFRT) have not been practiced uniformly across centers in different parts of the world. Countries in Asia share common cancer demographics, and we designed this survey for Federation of Asian Radiation Oncology (FARO) member countries to understand the usage and challenges in the delivery of ALFT in HNCs.

MATERIALS AND METHODS

A 21-point electronic survey (Federation of Asian Radiation Oncology Research Network [FERN]-S-005) was designed by the FERN and was circulated through the FARO research secretariat to the FARO council member countries and the responses were collected between August and November 2023.

RESULTS

Twelve of 14 member countries (85.7%) responded to the survey. Twenty-seven responses were received and 78% of the respondents belonged to government/teaching academic institute. 4/27 (14.8%) reported never using HYPO-RT for any of the clinical subsite of HNCs, while the majority (85.2%) used it for glottic cancers and 22% also used it for postoperative setting. Majority (77.7%) used a fractionation schedule with dose per fraction ranging between 2.2 and 2.5 Gy. 6/27 (22.2%) used AFRT for definitive setting and five of these also used concurrent chemoradiotherapy. 4/27 (14.8%) centers reported using HFRT. The most common reason (62.9%) for the limited usage of AFRT/HFRT was reported to be logistical, such as unavailability of machine slots, patient load, and so on.

CONCLUSION

The result of the survey suggests that among the ALFT strategies for HNCs, HYPO-RT schedules have common interest and feasibility among the FARO member countries and also highlights the challenges in the delivery of AFRT/HFRT in the Asian region.

DNA double-strand break repair capacity and normal tissue toxicity induced by radiotherapy

Radiation therapy is used in the treatment of various cancers, and advancements in irradiation techniques have further expanded its applicability. For radiation oncologists, predicting adverse events remains a critical challenge, even with these technological advancements. Although numerous studies have been conducted to predict individual radiosensitivity, no biomarkers have been clinically applied thus far. This review focuses on γ-H2AX foci and chromosomal aberrations, providing an overview of their association with normal tissue toxicities.

Transoral Laser Microsurgery and Transoral Robotic Surgery in Aging Patients: A State-of-The-Art Review

Purpose

In the present study, the findings related to the epidemiology, clinical presentation, and therapeutic outcomes of elderly patients treated with transoral laser microsurgery (TOLM) and transoral robotic surgery (TORS) for supraglottic laryngeal squamous cell carcinoma (LSCC) have been reviewed.

Methods

A PubMed, Cochrane Library, and Scopus literature search was conducted according to the PRISMA statements. Critical literature analysis was carried out considering the last advancement in TOLS and TORS, and their related surgical, functional, and survival outcomes.

Findings

The mean age of patients with supraglottic LSCCs has progressively increased in the past decades. The data on postoperative complications in elderly patients with LSCC are heterogeneous and contradictory. The thought of the age-related high risk of complications was based on open supraglottic laryngectomy (SGL), but not on TOLM and TORS findings, which do not support an age-related increase of most postoperative complications. The only complication that could be associated with age is aspiration. The adequate selection of patients undergoing TOLM or TORS, and the pre- to postoperative evaluation of swallowing function can prevent this risk. The OS of elderly patients treated with TOLM or TORS SGL could be lower compared to younger patients. However, the disease-free survival was not influenced by age, highlighting the role of comorbidities and intercurrent diseases in the presumed lower survival. The survival analysis could definitively consider the physiological age rather than the chronological age to investigate the impact of age on survival outcomes.

Conclusion

The current literature supports an important place of TOLM and TORS in managing cT1-T3 supraglottic LSCC. The preoperative geriatric, nutritional, and swallowing evaluations are important for ensuring an adequate selection of patients treated with TORS or TOLM SGL.

Emerging Radiotherapy Technologies for Head and Neck Squamous Cell Carcinoma: Challenges and Opportunities in the Era of Immunotherapy

Radiotherapy (RT) is an integral component in the multidisciplinary management of patients with head and neck squamous cell carcinoma (HNSCC). Significant advances have been made toward optimizing tumor control and toxicity profiles of RT for HNSCC in the past two decades. The development of intensity modulated radiotherapy (IMRT) and concurrent chemotherapy established the standard of care for most patients with locally advanced HNSCC around the turn of the century. More recently, selective dose escalation to the most radioresistant part of tumor and avoidance of the most critical substructures of organs at risk, often guided by functional imaging, allowed even further improvement in the therapeutic ratio of IMRT. Other highly conformal RT modalities, including intensity modulated proton therapy (IMPT) and stereotactic body radiotherapy (SBRT) are being increasingly utilized, although there are gaps in our understanding of the normal tissue complication probabilities and their relative biological effectiveness. There is renewed interest in spatially fractionated radiotherapy (SFRT), such as GRID and LATTICE radiotherapy, in both palliative and definitive settings. The emergence of immune checkpoint inhibitors (ICIs) has revolutionized the treatment of patients with recurrent and metastatic HNSCC. Novel RT modalities, including IMPT, SBRT, and SFRT, have the potential to reduce lymphopenia and immune suppression, stimulate anti-tumor immunity, and synergize with ICIs. The next frontier in the treatment of HNSCC may lie in the exploration of combined modality treatment with new RT technologies and ICIs.

The Rationale for Combining Hypofractionated Radiation and Hyperthermia

The conventional radiation treatment of cancer patients has typically involved a large number of daily treatments with relatively low doses of radiation. However, improved technology has now resulted in the increased use of fewer radiation fractions at a high dose per fraction. This latter approach is often referred to as hypofractionated irradiation. While conventional radiation typically kills tumor cells through the production of DNA damage, treatments with higher doses per fraction have been suggested to also kill cells via the induction of vascular damage. Such vascular effects will also increase the level of adverse microenvironmental conditions, such as hypoxia and acidity, that already exist in tumors. Cells existing in these adverse microenvironmental conditions are resistant to radiation but actually sensitive to hyperthermia (heating at 40-45 °C) treatment. This suggests that the combination of hypofractionated radiation and heat may be a viable treatment approach. While there are preliminary pre-clinical and even clinical studies investigating this option, there are actually no data on the optimal application for the greatest therapeutic benefit. In this critical review, we will present the rationale for combining hypofractionated radiation with hyperthermia and discuss what has been done and what should be done to establish this combination as an effective cancer therapy option.

Disease Control and Late Toxicity in Adaptive Dose Painting by Numbers Versus Nonadaptive Radiation Therapy for Head and Neck Cancer: A Randomized Controlled Phase 2 Trial

PURPOSE

Local recurrence remains the main cause of death in stage III-IV nonmetastatic head and neck cancer (HNC), with relapse-prone regions within high 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET)-signal gross tumor volume. We investigated if dose escalation within this subvolume combined with a 3-phase treatment adaptation could increase local (LC) and regional (RC) control at equal or minimized radiation-induced toxicity, by comparing adaptive 18F-FDG-PET voxel intensity-based dose painting by numbers (A-DPBN) with nonadaptive standard intensity modulated radiation therapy (S-IMRT).

METHODS AND MATERIALS

This 2-center randomized controlled phase 2 trial assigned (1:1) patients to receive A-DPBN or S-IMRT (+/-chemotherapy). Eligibility: nonmetastatic HNC of oral cavity, oro-/hypopharynx, or larynx, needing radio(chemo)therapy; T1-4N0-3 (exception: T1-2N0 glottic); KPS ≥ 70; ≥18 years; and informed consent.

PRIMARY OUTCOMES

1-year LC and RC. The dose prescription for A-DPBN was intercurrently adapted in 2 steps to an absolute dose-volume limit (≤1.75 cm3 can receive >84 Gy and normalized isoeffective dose >96 Gy) as a safety measure during the study course after 4/7 A-DPBN patients developed ≥G3 mucosal ulcers.

RESULTS

Ninety-five patients were randomized (A-DPBN, 47; S-IMRT, 48). Median follow-up was 31 months (IQR, 14-48 months); 29 patients died (17 of cancer progression). A-DPBN resulted in superior LC compared with S-IMRT, with 1- and 2-year LC of 91% and 88% versus 78% and 75%, respectively (hazard ratio, 3.13; 95% CI, 1.13-8.71; P = .021). RC and overall survival were comparable between arms, as was overall grade (G) ≥3 late toxicity (36% vs 20%; P = .1). More ≥G3 late mucosal ulcers were observed in active smokers (29% vs 3%; P = .005) and alcohol users (33% vs 13%; P = .02), independent of treatment arm. Similarly, in the A-DPBN arm, significantly more patients who smoked at diagnosis developed ≥G3 (46% vs 12%; P = .005) and ≥G4 (29% vs 8%; P = .048) mucosal ulcers. One arterial blowout occurred after a G5 mucosal toxicity.

CONCLUSIONS

A-DPBN resulted in superior 1- and 2-year LC for HNC compared with S-IMRT. This supports further exploration in multicenter phase 3 trials. It will, however, be challenging to recruit a substantial patient sample for such trials, as concerns have arisen regarding the association of late mucosal ulcers when escalating the dose in continuing smokers.

Efficacy and Toxicity of Moderately Hypofractionated Radiation Therapy with Helical TomoTherapy Versus Conventional Radiation Therapy in Patients with Unresectable Stage III Non-Small Cell Lung Cancer Receiving Concurrent Chemotherapy: A Multicenter, Randomized Phase 3 Trial

PURPOSE

The standard treatment schedule for unresectable stage III non-small cell lung cancer (NSCLC) is chemotherapy with concurrent radiation therapy (60 Gy delivered in 30 fractions), although moderately hypofractionated radiation therapy (Hypo-RT) has also been considered as an alternative strategy. This study aimed to compare the efficacy and toxicity of moderately Hypo-RT with helical TomoTherapy versus conventionally fractionated radiation therapy (Con-RT) in patients with unresectable stage III NSCLC receiving concurrent chemotherapy.

METHODS AND MATERIALS

In this randomized, multicenter, nonblinded phase 3 clinical trial, eligible patients were randomised at a 1:1 ratio to either the Hypo-RT group (60 Gy in 20 fractions) or Con-RT group (60 Gy in 30 fractions). All patients received 2 cycles of concurrent platinum-based chemotherapy plus 2 cycles of consolidation therapy. The primary endpoint was 3-year overall survival (OS) in the intention-to-treat population. The secondary endpoints were progression-free survival and treatment-related adverse events.

RESULTS

A total of 146 patients were enrolled from July 27, 2018, to November 1, 2021. The median follow-up was 46 months. The 3-year OS rates in the Hypo-RT and Con-RT groups were 58.4% and 38.4%, respectively (P = .02). The median OS from randomisation was 41 months in the Hypo-RT group and 30 months in the Con-RT group (hazard ratio, 0.61; 95% confidence interval, 0.40-0.94; P = .02). There was no significant difference in the rates of grade ≥2 treatment-related adverse events between the 2 groups.

CONCLUSIONS

Moderately Hypo-RT using helical TomoTherapy may improve OS in patients with unresectable stage III NSCLC, while maintaining toxicity rates.

FGD-PET/CT three months after (chemo)radiotherapy for head and neck squamous cell carcinoma spares considerable number of patients from a salvage neck dissection

PURPOSE

In the last decades FDG-PET/CT is increasingly used in combination with the standard diagnostic modalities (MRI + US-FNA) to identify residual neck disease (RND) after (chemo)radiotherapy for head-and-neck squamous cell carcinoma (HNSCC). The purpose of the current study is to identify the impact of increasing use of FDG-PET/CT on the accuracy of patient selection for salvage neck dissection (SND).

MATERIALS AND METHODS

Between 2008 and 2022, 908 consecutive patients with node-positive HNSCC were treated with (chemo)radiotherapy in our institution.

PRIMARY ENDPOINT

positive predictive value (PPV) of FDG-PET/CT for pathologic-confirmed RND (pRND) after SND, compared to the standard of care; MRI + US-FNA. Secondary endpoints: oncologic outcomes.

RESULTS

Of the entire group, 130 patients (14 %) received SND. Of them only 53 patients (41 %) had pRND at the SND-specimens. The PPV of FDG-PET/CT for the detection of pRND was considerably better, compared to MRI + US-FNA; 89 % and 65 %, respectively. If FDG-PET/CT showed metabolic CR, these patients did not undergo SND. The NPV was 97.5 %, as only 2.5 % of these patients developed delayed regional failure. FDG-PET/CT considerably improved the accuracy of patient selection for SND, as significantly more patients treated in the second period, compared to first period of the study (n = 454 each) still had vital tumor at SND-specimen (53 % and 31 %, p = 0.008). Regional recurrence free-survival, DFS, OS and HNSCC-death were significantly worse in patients with pRND (p < 0.05) CONCLUSIONS: Incorporating FDG-PET/CT into the diagnostic pathway for the response evaluation after (chemo)radiotherapy significantly improved the accuracy of patient selection for SND and spared considerable number of patients (>20 %) from unnecessary SND. For patients with metabolic CR, SND can safely be omitted while for patients with no metabolic CR, SND is strongly advocated.

Radiation Therapy for HPV-Positive Oropharyngeal Squamous Cell Carcinoma: An ASTRO Clinical Practice Guideline

PURPOSE

Human Papilloma Virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is a distinct disease from other head and neck tumors. This guideline provides evidence-based recommendations on the critical decisions in its curative treatment, including both definitive and postoperative radiation therapy (RT) management.

METHODS

ASTRO convened a task force to address 5 key questions on the use of RT for management of HPV-associated OPSCC. These questions included indications for definitive and postoperative RT and chemoradiation; dose-fractionation regimens and treatment volumes; preferred RT techniques and normal tissue considerations; and posttreatment management decisions. The task force did not address indications for primary surgery versus RT. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Concurrent cisplatin is recommended for patients receiving definitive RT with T3-4 disease and/or 1 node >3 cm, or multiple nodes. For similar patients who are ineligible for cisplatin, concurrent cetuximab, carboplatin/5-fluorouracil, or taxane-based systemic therapy are conditionally recommended. In the postoperative setting, RT with concurrent cisplatin (either schedule) is recommended for positive surgical margins or extranodal extension. Postoperative RT alone is recommended for pT3-4 disease, >2 nodes, or a single node >3 cm. Observation is conditionally recommended for pT1-2 disease and a single node ≤3 cm without other risk factors. For patients treated with definitive RT with concurrent systemic therapy, 7000 cGy in 33 to 35 fractions is recommended, and for patients receiving postoperative RT without positive surgical margins and extranodal extension, 5600 to 6000 cGy is recommended. For all patients receiving RT, intensity modulated RT over 3-dimensional techniques with reduction in dose to critical organs at risk (including salivary and swallowing structures) is recommended. Reassessment with positron emission tomography-computed tomography is recommended approximately 3 months after definitive RT/chemoradiation, and neck dissection is recommended for convincing evidence of residual disease; for equivocal positron emission tomography-computed tomography findings, either neck dissection or repeat imaging is recommended.

CONCLUSIONS

The role and practice of RT continues to evolve for HPV-associated OPSCC, and these guidelines inform best clinical practice based on the available evidence.

Understanding the impact of radiotherapy fractionation on overall survival in a large head and neck squamous cell carcinoma dataset: a comprehensive approach combining mechanistic and machine learning models

Introduction

Treating head and neck squamous cell carcinomas (HNSCC), especially human papillomavirus negative (HPV-) and locally advanced cases, remains difficult. Our previous analyses of radiotherapy-only HNSCC clinical trials data using mechanistically-motivated models of tumor repopulation and killing by radiotherapy predicted that hyperfractionation with twice-daily fractions, or hypofractionation involving increased doses/fraction and reduced treatment durations, both improve tumor control and reduce late normal tissue toxicity, compared with standard protocols using 35×2 Gy. Here we further investigated the validity of these conclusions by analyzing a large modern dataset on 3,346 HNSCC radiotherapy patients from the University Health Network in Toronto, Canada, where 42.5% of patients were also treated with chemotherapy.

Methods

We used a two-step approach that combines mechanistic modeling concepts with state-of-the-art machine learning, beginning with Random Survival Forests (RSF) for an exploratory analysis and followed by Causal Survival Forests (CSF) for a focused causal analysis. The mechanistic concept of biologically effective dose (BED) was implemented for the standard dose-independent (DI) tumor repopulation model, our alternative dose-dependent (DD) repopulation model, and a simple model with no repopulation (BEDsimp). These BED variants were included in the RSF model, along with age, stage, HPV status and other relevant variables, to predict patient overall survival (OS) and cause-specific mortality (deaths from the index cancer, other cancers or other causes).

Results

Model interpretation using Shapley Additive Explanations (SHAP) values and correlation matrices showed that high values of BEDDD or BEDDI, but not BEDsimp, were associated with decreased patient mortality. Targeted causal inference analyses were then performed using CSF to estimate the causal effect of each BED variant on OS. They revealed that high BEDDD (>61.8 Gy) or BEDDI (>57.6 Gy), but not BEDsimp, increased patient restricted mean survival time (RMST) by 0.5-1.0 years and increased survival probability (SP) by 5-15% several years after treatment. In addition to population-level averages, CSF generated individual-level causal effect estimates for each patient, facilitating personalized medicine.

Discussion

These findings are generally consistent with those of our previous mechanistic modeling, implying the potential benefits of altered radiotherapy fractionation schemes (e.g. 25×2.4 Gy, 20×2.75 Gy, 18×3.0 Gy) which increase BEDDD and BEDDI and counteract tumor repopulation more effectively than standard fractionation. Such regimens may represent potentially useful hypofractionated options for treating HNSCC.

Fractionated irradiation induces radioresistant oral carcinoma cells with enhanced malignant phenotypes

OBJECTIVE

The fact that certain oral carcinoma patients experience radiotherapy failure implies that a more radioresistant and aggressive phenotype of surviving cancer cells potentially occurs during treatment. Our study aimed to establish radioresistant oral cancer cells through a fractionated irradiation protocol that mimics clinically relevant radiotherapy dosing strategies and to investigate all-round alterations in the malignant phenotype.

METHODS

Radioresistant oral carcinoma cells were generated by exposing Cal27 and Detroit 562 cells to 60 Gy radiation in 10 dose-escalating fractions and verified by cell immunofluorescence. Specific markers related to the epithelial-mesenchymal transition (EMT) process and the cancer stem cell (CSC) phenotype were assessed by Western blotting. Cell invasion and migration were evaluated using Matrigel-coated transwell and wound healing assays, respectively. Nontargeted metabolomics was used to mechanistically delineate the potential metabolic patterns linked to EMT and CSCs; the CSC phenotype was also examined by sphere formation assays and cell immunofluorescence.

RESULTS

Radioresistant oral carcinoma cell lines were successfully established and validated. These cells exhibited enhanced EMT and increase in both cell invasion and migration. These radioresistant cells further demonstrated a high metabolic profile, notably marked by lipid metabolism reprogramming and functional enrichment of ATP-binding cassette (ABC) transporters. Consistently, enhanced CSC phenotype in radioresistant cells was confirmed by elevated expression of stemness markers and increased sphere-forming capacity.

CONCLUSION

Radioresistant oral carcinoma cells subjected to fractionated radiation exhibit an augmented malignant phenotype. The metabolic characteristics linked to enhanced EMT and CSC phenotypes provide potential targets for improving radiotherapy in oral carcinoma.

Concomitant Boost With Six Fractions of Radiation a Week in Locally Advanced Head and Neck Cancer Patients: A Prospective Study

Background and objective Radiation therapy plays a significant role in the radical treatment of locally advanced head and neck cancers. Studies have shown the radiobiological advantage of accelerated chemoradiation over conventional chemoradiation as it reduces the chances of accelerated repopulation and decreases overall treatment time. This study aimed to assess the response and toxicities of accelerated concomitant chemoradiation in locally advanced head and neck cancer patients. Methods A total of 51 patients were enrolled and treated with accelerated concomitant chemoradiation, receiving one fraction of radiation per day, six fractions per week, with the sixth fraction as a boost on Saturdays, with weekly concurrent cisplatin at 40 mg/m2. Patients were followed up till six months after treatment completion. Radiological investigation was done to assess response according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.128, and acute toxicities were assessed according to Radiation Therapy Oncology Group (RTOG) criteria. Results The median follow-up period was six months; 28 patients (62.22%) had a complete response and 17 (37.78%) had a partial response at six months post-completion of the treatment. The maximum acute toxicities developed at the completion of treatment. Grade III and IV mucositis developed in 14 patients (31.11%) and grade III dermatitis developed in one patient (2.22%), without any grade IV dermatitis during the total duration of treatment. The toxicities were manageable, and most of them resolved after three months of treatment completion. Conclusions Accelerated concomitant chemoradiation with six fractions of radiation in a week led to a decrease in overall treatment time. Of note, 62.22% of patients had complete remission, with manageable acute mucositis and dermatitis, which resolved in 82% and 67%, respectively within three months of treatment completion. However, further studies involving larger samples and longer follow-ups are needed for this regimen to be established as the standard of care in the future.

Radiation-induced skin injury in the head and neck region: pathogenesis, clinics, prevention, treatment considerations and proposal for management algorithm

Worldwide increase of head and neck cancers ranks these malignancies among top causes of cancer in human population. Radiation induced skin injury (RISI) is one of the major side effects of radiotherapy (RT). Skin of the neck is exposed to radiation due to necessity of therapeutic or prophylactic (elective) irradiation of neck lymph nodes and target organs, including the larynx and hypopharynx. The location of the neck exposes these regions of the skin to various additional exposomes such as ultraviolet radiation (UVR), pollution and cigarette smoke. There are many controversies or inconsistencies regarding RISI, from molecular aspects and therapy to terminology. There is lack of high-quality and large-sample studies in both forms of RISI: acute (aRISI) and chronic (cRISI). Finally, no gold standards in the management of aRISI and cRISI have been established yet. In this article, the authors discuss the pathogenesis, clinical picture, prevention and clinical interventions and present a proposed treatment algorithm.

Comparison of 3-year local control using DAHANCA radiotherapy guidelines before and after implementation of five millimetres geometrical GTV to high-dose CTV margin

INTRODUCTION

Treatment planning using a five-millimetre geometrical margin from GTV to high-dose CTV (CTV1) has been used in DAHANCA treatment centres since 2013. We aimed to evaluate changes in CTV1 volumes, local control (LC), and recurrence pattern after the implementation of five-millimetre geometrical margins nationally.

MATERIALS AND METHODS

1,948 patients with pharyngeal, and laryngeal squamous cell carcinomas completed definitive IMRT-based treatment in 2010-2012 and 2013-2015 in three centres. The patient-specific margin was calculated as median surface distance from primary tumour GTV (GTV-T) to CTV1. Radiologically verified local recurrences were analysed using a centre of mass (COM) of the delineated recurrence volume, measuring the shortest distance between COM to GTV-T and CTV1 boundaries.

RESULTS

Median GTV-CTV1 was 0.9 (0.0-0.97) and 0.47 cm (0.4-0.5) for 2010-2012 and 2013-2015, respectively. Median CTV1 changed in three centres from 76, 28, 42 cm3 to 61, 53, 62 cm3 for 2010-2012 and 2013-2015, respectively. Local failures occurred at 247 patients during first three years after radiotherapy. The 3-year LC rate for 2010-2012 and 2013-2015 was 0.84 and 0.87 (p = 0.06). Out of 146 radiology-verified analysable local recurrences, 102 (69.9%) were inside the CTV1. In 74.6% and 91% of cases, the LRs were covered by 95% isodose in 2010-2012 and 2013-2015, respectively.

CONCLUSION

DAHANCA radiotherapy guidelines based on a geometrically generated isotropic CTV1 margin led to less variation in treatment volumes and between centres than previous guidelines. The transition towards consensus GTV-CTV1 margins did not influence local tumour control. The majority of local recurrences were inside CTV1 and covered by the prescription dose.

Does adaptive radiotherapy for head and neck cancer favorably impact dosimetric, clinical, and toxicity outcomes?: A review

PURPOSE

The current review aims to summarize the international experience of the impact of adaptive radiotherapy on dosimetry and clinical and toxicity outcomes. Additionally, it might trigger Radiation Oncologists to use ART and evaluate whether ART improves target volume coverage and/or normal tissue sparing and, consequently, therapeutic results.

MATERIALS AND METHODS

We conducted an electronic literature search of PubMed/MEDLINE and ScienceDirect from January 2007 to January 2023. The search adhered to the PRISMA guidelines and employed keywords such as ART, HNC, parotid gland, and target volume. Furthermore, we examined the reference lists for studies pertinent to the present review. This study included both retrospective and prospective studies that were considered for inclusion.

CONCLUSION

ART replanning appears to be a sustainable strategy to minimize toxicity by improving normal tissue sparing. Furthermore, it can enhance target volume coverage by correctly determining the specific dose to be delivered to the tumor. In conclusion, this review confirmed that ART benefits dosimetric, clinical/therapeutic, and toxicity outcomes.

Determining the library size for the optimal output plan in the RapidPlan knowledge-based planning system using multicriteria optimization

OBJECTIVES

The aim of this study was to determine the number of trade-off explored (TO) library plans required for building a RapidPlan (RP) library that would generate the optimal clinical treatment plan.

METHODS

We developed 2 RP models, 1 each for the 2 clinical sites, head and neck (HN) and cervix. The models were created using 100 plans and were validated using 70 plans (VP) for each site respectively. Each of the 2 libraries comprising 100 TO plans was divided into 5 different subsets of library plans comprising 20, 40, 60, 80, and 100 plans, leading to 5 different RP models for each site. For every validation patient, a TO plan (TO_VP) was created. For every patient, 5 RP plans were automatically generated using RP models. The dosimetric parameters of the 6 plans (TO_VP + 5 RP plans) were compared using Pearson correlation and Greenhouse-Geisser analysis.

RESULTS

Planning target volume (PTV) dose volume parameters PTVD95% in 6 competing plans varied between 97.6 ± 0.7% and 98.1 ± 0.6% in HN cases and 98.8 ± 0.3% and 99.0 ± 0.4% in cervix cases. Overall, for both sites, the mean variations in organ at risk (OAR) doses or volumes were within 50 cGy, 0.5%, and 0.2 cc between library plans, and if TO_VP was included the variations deteriorated to 180 cGy, 0.4%, and 15 cc. All OARs in both sites, except D0.1 ccspine, showed a statistically insignificant variation between all plans.

CONCLUSIONS

Dosimetric variation among various output plans generated from 5 RP libraries is minimal and clinically insignificant. The optimal output plan can be derived from the least-weighted library consisting of 20 plans.

ADVANCES IN KNOWLEDGE

This article shows that, when the constituent plans are subjected to trade-off exploration, the number of constituent plans for a knowledge-based planning module is not relevant in terms of its dosimetric output.

The role of intratumoral microorganisms in the progression and immunotherapeutic efficacy of head and neck cancer

The effectiveness of cancer immunization is largely dependent on the tumor’s microenvironment, especially the tumor immune microenvironment. Emerging studies say microbes exist in tumor cells and immune cells, suggesting that these microbes can affect the state of the immune microenvironment of the tumor. Our comprehensive review navigates the intricate nexus between intratumoral microorganisms and their role in tumor biology and immune modulation. Beginning with an exploration of the historical acknowledgment of microorganisms within tumors, the article underscores the evolution of the tumor microenvironment (TME) and its subsequent implications. Using findings from recent studies, we delve into the unique bacterial compositions across different tumor types and their influence on tumor growth, DNA damage, and immune regulation. Furthermore, we illuminate the potential therapeutic implications of targeting these intratumoral microorganisms, emphasizing their multifaceted roles from drug delivery agents to immunotherapy enhancers. As advancements in next-generation sequencing (NGS) technology redefine our understanding of the tumor microbiome, the article underscores the importance of discerning their precise role in tumor progression and tailoring therapeutic interventions. The review culminates by emphasizing ongoing challenges and the pressing need for further research to harness the potential of intratumoral microorganisms in cancer care.

Mechanisms of Action in FLASH Radiotherapy: A Comprehensive Review of Physicochemical and Biological Processes on Cancerous and Normal Cells

The advent of FLASH radiotherapy (FLASH-RT) has brought forth a paradigm shift in cancer treatment, showcasing remarkable normal cell sparing effects with ultra-high dose rates (>40 Gy/s). This review delves into the multifaceted mechanisms underpinning the efficacy of FLASH effect, examining both physicochemical and biological hypotheses in cell biophysics. The physicochemical process encompasses oxygen depletion, reactive oxygen species, and free radical recombination. In parallel, the biological process explores the FLASH effect on the immune system and on blood vessels in treatment sites such as the brain, lung, gastrointestinal tract, skin, and subcutaneous tissue. This review investigated the selective targeting of cancer cells and the modulation of the tumor microenvironment through FLASH-RT. Examining these mechanisms, we explore the implications and challenges of integrating FLASH-RT into cancer treatment. The potential to spare normal cells, boost the immune response, and modify the tumor vasculature offers new therapeutic strategies. Despite progress in understanding FLASH-RT, this review highlights knowledge gaps, emphasizing the need for further research to optimize its clinical applications. The synthesis of physicochemical and biological insights serves as a comprehensive resource for cell biology, molecular biology, and biophysics researchers and clinicians navigating the evolution of FLASH-RT in cancer therapy.

Accelerated Fractionated Radiation Therapy for Localized Glottic Carcinoma

BACKGROUND

The aim of this study is to examine the outcomes of an accelerated fractionated irradiation for N0 glottic carcinoma.

METHODS

In this retrospective analysis, 29 patients with N0 glottic carcinoma treated by radiation therapy were enrolled. Thirteen patients had T1a disease, six had T1b disease, and ten had T2 disease. A fractional dose of 2.1 Gy was administered to seven patients. The total doses were 65.1 and 67.2 Gy in four and three patients, respectively. A fractional dose of 2.25 Gy was administered to 22 patients. The total doses were 63 and 67.5 Gy in 21 patients and 1 patient with T2 disease, respectively. Additionally, 13 patients underwent the use of TS-1 (80-100 mg per day).

RESULTS

The median follow-up period was 33 months, and the 3-year local control rate was 95.6%. No patient had a lymph node or distant recurrence. As acute adverse events, grades 2 and 3 dermatitis were observed in 18 patients and 1 patient, and grades 2 and 3 mucositis were observed in 15 patients and 1 patient. As a late adverse event, one patient required tracheotomy because of laryngeal edema occurring.

CONCLUSIONS

Accelerated fractionated irradiation may be an option in the radiation therapy of N0 glottic carcinoma because of its ability to shorten the treatment time.

Evaluation of specific RBE in different cells of hippocampus under high-dose proton irradiation in rats

The study aimed to determine the specific relative biological effectiveness (RBE) of various cells in the hippocampus following proton irradiation. Sixty Sprague-Dawley rats were randomly allocated to 5 groups receiving 20 or 30 Gy of proton or photon irradiation. Pathomorphological neuronal damage in the hippocampus was assessed using Hematoxylin-eosin (HE) staining. The expression level of NeuN, Nestin, Caspase-3, Olig2, CD68 and CD45 were determined by immunohistochemistry (IHC). The RBE range established by comparing the effects of proton and photon irradiation at equivalent biological outcomes. Proton20Gy induced more severe damage to neurons than photon20Gy, but showed no difference compared to photon30Gy. The RBE of neuron was determined to be 1.65. Similarly, both proton20Gy and proton30Gy resulted in more inhibition of oligodendrocytes and activation of microglia in the hippocampal regions than photon20Gy and photon30Gy. However, the expression of Olig2 was higher and CD68 was lower in the proton20Gy group than in the photon30Gy group. The RBE of oligodendrocyte and microglia was estimated to be between 1.1 to 1.65. For neural stem cells (NSCs) and immune cells, there were no significant difference in the expression of Nestin and CD45 between proton and photon irradiation (both 20 and 30 Gy). Therefore, the RBE for NSCs and immune cell was determined to be 1.1. These findings highlight the varying RBE values of different cells in the hippocampus in vivo. Moreover, the actual RBE of the hippocampus may be higher than 1.1, suggesting that using as RBE value of 1.1 in clinical practice may underestimate the toxicities induced by proton radiation.

High PD-L1 expression on immune cells along with increased density of tumor-infiltrating lymphocytes predicts a favorable survival outcome for patients with loco-regionally advanced head and neck cancer: early results from a prospective study

Introduction

In the era of personalized medicine and treatment optimization, use of immune biomarkers holds promise for estimating the prognosis of patients with head and neck squamous cell carcinoma (HNSCC) undergoing definitive treatment.

Methods

To evaluate the prognostic potential of immune biomarkers, we conducted a prospective monocentric cohort study with loco-regionally advanced HNSCC patients indicated for definitive radiotherapy/radiochemotherapy at the Department of Oncology, Ostrava University Hospital, Czech Republic, between June 2020 and August 2023. We focused on the expression of programmed death ligand 1 (PD-L1) and tumor-infiltrating lymphocytes (TILs) relative to overall survival (OS) and specific survival rates. Associations between biomarkers and survival rates were assessed by crude and adjusted hazard ratios (cHR, aHR, respectively) obtained from Cox proportional hazards regression.

Results

Among a total of 55 patients within a median follow-up of 19.7 months, there were 21 (38.2%) all-cause deaths and 15 (27.3%) cancer-related deaths. An overall survival (OS) rate of 61.8% and a disease-specific survival (DSS) rate of 72.7% were recorded. A significant association between survival rates and a ≥10% difference in PD-L1 expression on immune versus tumor cells (high PD-L1IC expression) was documented regardless of the type of analysis (univariate or multivariate). In addition, a stronger association was confirmed for OS and the composite biomarker high PD-L1IC expression along with either median-higher CD8+ TIL count or increased TIL density ≥30%, as indicated by an aHR of 0.08 (95% CI, 0.01 to 0.52) and 0.07 (95% CI, 0.01 to 0.46), respectively. Similar results were demonstrated for other specific survival rates.

Discussion

The early outcomes of the present study suggest the utility of a strong prognostic factor involving a composite biomarker high PD-L1IC expression along with increased TIL density in HNSCC patients undergoing definitive radiotherapy and radiochemotherapy.

Trial registration

The study is registered with Clinicaltrials.gov. - NCT05941676.

Water-soluble 4-(dimethylaminomethyl)heliomycin exerts greater antitumor effects than parental heliomycin by targeting the tNOX-SIRT1 axis and apoptosis in oral cancer cells

The antibiotic heliomycin (resistomycin), which is generated from Streptomyces resistomycificus, has multiple activities, including anticancer effects. Heliomycin was first described in the 1960s, but its clinical applications have been hindered by extremely low solubility. A series of 4-aminomethyl derivatives of heliomycin were synthesized to increase water solubility; studies showed that they had anti-proliferative effects, but the drug targets remained unknown. In this study, we conducted cellular thermal shift assays (CETSA) and molecular docking simulations to identify and validate that heliomycin and its water-soluble derivative, 4-(dimethylaminomethyl)heliomycin (designated compound 4-dmH) engaged and targeted with sirtuin-1 (SIRT1) in p53-functional SAS and p53-mutated HSC-3 oral cancer cells. We further addressed the cellular outcome of SIRT1 inhibition by these compounds and found that, in addition to SIRT1, the water-soluble 4-dmH preferentially targeted a tumor-associated NADH oxidase (tNOX, ENOX2). The direct binding of 4-dmH to tNOX decreased the oxidation of NADH to NAD+ which diminished NAD+-dependent SIRT1 deacetylase activity, ultimately inducing apoptosis and significant cytotoxicity in both cell types, as opposed to the parental heliomycin-induced autophagy. We also observed that tNOX and SIRT1 were both upregulated in tumor tissues of oral cancer patients compared to adjacent normal tissues, suggesting their clinical relevance. Finally, the better therapeutic efficacy of 4-dmH was confirmed in tumor-bearing mice, which showed greater tNOX and SIRT1 downregulation and tumor volume reduction when treated with 4-dmH compared to heliomycin. Taken together, our in vitro and in vivo findings suggest that the multifaceted properties of water-soluble 4-dmH enable it to offer superior antitumor value compared to parental heliomycin, and indicated that it functions through targeting the tNOX-NAD+-SIRT1 axis to induce apoptosis in oral cancer cells.

Tumor volume and cancer stem cell expression as prognostic markers for high-dose loco-regional failure in head and neck squamous cell carcinoma - A DAHANCA 19 study

BACKGROUND AND PURPOSE

Reliable and accessible biomarkers for patients with Head and Neck Squamous Cell Carcinoma (HNSCC) are warranted for biologically driven radiotherapy (RT). This study aimed to investigate the prognostic value of putative cancer stem cell (CSC) markers, hypoxia, and tumor volume using loco-regional high-dose failure (HDF) as endpoint.

MATERIALS AND METHODS

Tumor tissue was retrieved from patients treated with primary chemo-(C-)RT and nimorazole for HNSCC in the Danish Head and Neck Cancer Study Group (DAHANCA) 19 study. Tumor volume, hypoxic classification, and expression of CSC markers CD44, SLC3A2, and MET were analyzed. For patients with eligible data on all parameters (n = 340), the risk of HDF following primary chemo-(C-)RT were analyzed by these biomarkers as a whole and stratified for p16-positive oropharynx (p16 + OPSCC) vs p16-negative (p16-) tumors (oral cavity, p16- oropharynx, hypopharynx and larynx).

RESULTS

Higher risk of HDF was seen for patients with larger primary and nodal volume (>25 cm3, Hazard Ratio (HR): 3.00 [95 % CI: 1.73-5.18]), high SLC3A2 (HR: 2.99 [1.28-6.99]), CD44 (>30 % positive, HR: 2.29 [1.05-5.00]), and p16- tumors (HR: 2.53 [1.05-6.11]). p16- tumors had a higher CSC marker expression than p16 + OPSCC. The factors associated with the highest risk of HDF were larger volume (HR: 3.29 [1.79-6.04]) for p16- tumors (n = 178) and high SLC3A2 (HR: 6.19 [1.58-24.23]) for p16 + OPSCC (n = 162).

CONCLUSION

Tumor volume, p16, and CSC markers are potential biomarkers for HDF for patients with HNSCC treated with (C-)RT. Lower expression of CSC in p16 + OPSCC may contribute to better tumor control.

[French national standard for the treatment of squamous cell carcinoma of upper aero-digestive tract - General principles of treatment]

OBJECTIVES

The management of upper aerodigestive tract cancers is a complex specialty. It is essential to provide an update to establish optimal care. At the initiative of the INCa and under the auspices of the SFORL, the scientific committee, led by Professor Béatrix Barry, Dr. Gilles Dolivet, and Dr. Dominique De Raucourt, decided to develop a reference framework aimed at defining, in a scientific and consensus-based manner, the general principles of treatment for upper aerodigestive tract cancers applicable to all sub-locations.

METHODOLOGY

To develop this framework, a multidisciplinary team of practitioners was formed. A systematic analysis of the literature was conducted to produce recommendations classified by grades, in accordance with the standards of the French National Authority for Health (HAS).

RESULTS

The grading of recommendations according to HAS standards has allowed the establishment of a reference for patient care based on several criteria. In this framework, patients benefit from differentiated care based on prognostic factors they present (age, comorbidities, TNM status, HPV status, etc.), conditions of implementation, and quality criteria for indicated surgery (operability, resectability, margin quality, mutilation, salvage surgery), as well as quality criteria for radiotherapy (target volume, implementation time, etc.). The role of medical and postoperative treatments was also evaluated based on specific criteria. Finally, supportive care must be organized from the beginning and throughout the patients' care journey.

CONCLUSION

All collected data have led to the development of a comprehensive framework aimed at harmonizing practices nationally, facilitating decision-making in multidisciplinary consultation meetings, promoting equality in practices, and providing a state-of-the-art and reference practices for assessing the quality of care. This new framework is intended to be updated every 5 years to best reflect the latest advances in the field.

Efficacy of Lvpao Powder on Radiation Therapy-Induced Mucositis: A Retrospective Study of 114 Patients With Head and Neck Carcinoma

Purpose

To compare the efficacy and safety of Kangfuxin solution and lvpao powder on mucositis induced by radiation therapy in head and neck carcinoma patients. We retrospectively analyzed 114 patients with head and neck malignant tumors in our center.

Methods and Materials

Patients were given Kangfuxin solution to rinse the mouth or Lvpao powder sprayed on oral mucosa after the solution use. The side effect was evaluated by Common Terminology Criteria for Adverse Events version 4.0.

Results

The grade 3 mucositis occurred in 32.9% (23/70) and 11.4% (5/44) in Kangfuxin solution group and Kangfuxin solution + lvpao powder group, respectively (P = .009). The pain score of the Kangfuxin solution group was significantly higher than that of the Kangfuxin solution and lvpao powder group, with 4.26 ± 0.81 versus 3.75 ± 1.03 (P = .007). The time of symptom relief in the combined group was significantly shorter than that in the single drug group, with 3 days versus 6 days (P = .000). The weight loss of the former groups was bigger than that of the latter group (6.67 ± 1.20 kg vs 5.95 ± 0.94 kg; P = .001). There was no statistical difference in the limitations in mouth opening (P = .164).

Conclusions

Lvpao powder is safe and effective as a mucosal repair drug in accelerating the recovery of patients and reducing their body weight.

Locally Advanced oral Squamous cell Carcinomas: Auditing and Outcome Appraisal

Introduction: Patients with OSCC in India (oral squamous cell carcinoma) presents at a later stage with approximately 28% presenting at stage III and 64% at stage IV disease. In this retrospective study we have reviewed the treatment modalities rendered and outcomes associated for the management of locally advanced oral squamous cell carcinoma in our Institute. We evaluated the survival data and the factors effecting survival. Methods: Kaplan Meir method was used to evaluate OS and DFS rate and log rank test was used to compare the survival amongst groups. Cox regression analysis (univariate and multivariate) was used to evaluate the hazard ratio to find out the possible factors influencing risk of death and disease. Results: The median OS and DFS in our study were 32 and 24 months respectively. On a subset analysis of only T4b patients who underwent either upfront surgery or induction chemotherapy followed by surgery there was no significant difference in OS and DFS. All patients with TURD had partial response after induction chemotherapy and were subjected to surgical resection followed by adjuvant therapy. Conclusion: Extracapsular spread, bone involvement, skin infiltration, treatments, surgical margins and Lymph node size are the prime predictors of survival.Upfront surgery remains the standard of care for resectable LAOSCC. Induction chemotherapy might improve the resectability in technically unresectable OSCC. There is no difference in survival between concurrent chemoradiation, sequential chemoradiation and radical radiotherapy in the management of unresectable disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-04168-4.

Phase I feasibility study of Olaparib in combination with loco-regional radiotherapy in head and neck squamous cell carcinoma

Purpose

PARP-inhibitors have potent radiosensitizing properties in pre-clinical models. To identify the maximum tolerated dose (MTD) of the PARP-inhibitor Olaparib in combination with radiotherapy in patients with head and neck cancer, a single institutional phase-I dose escalation trial was initiated.

Patients and methods

The starting dose of Olaparib was 25 mg BID, combined with radiotherapy (70 Gy in 35 fractions). The MTD was defined as the highest dose-level at which not more than 20 % of patients experience dose-limiting toxicities (DLT) or as the highest reached dose in the absence of DLT's.

Results

One week Olaparib-only treatment (25 mg QD) was administered to all patients prior to the start of radiotherapy. In dose-level I, Olaparib (25 mg BID) was combined with accelerated radiotherapy (70 Gy in 6 weeks). Because of DLT's in 3 of the 4 treated patients (acute tracheotomy 5 and 7 months and osteoradionecrosis 7 months after treatment), the Olaparib dose was de-escalated to 25 mg QD, and combined with conventional radiotherapy (70 Gy in 7 weeks) (dose-level II). There were no DLT's observed in 5 patients treated within dose-level II. After a median follow-up of 60 months, the 4-year LRC and OS rates were 77.8 % and 88.9 %, respectively.

Conclusion

Olaparib 25 mg QD combined with conventionally fractionated radiotherapy was well tolerated and identified as the MTD while severe DLT's were observed when Olaparib 25 mg BID was combined with accelerated radiation. This combination might be further explored in future Olaparib dose escalation studies in patients with locally-advanced HNSCC unfit for cisplatin-based chemoradiotherapy.

Season of radiotherapy and outcomes of head & neck cancer patients in the MACH-NC & MARCH meta-analyses

BACKGROUND

A single institution retrospective study suggested that head and neck squamous cell cancer (HNSCC) patients receiving radiotherapy (RT) during "dark" season (fall/winter) may have better outcomes than those treated during "light" season (spring/summer), possibly secondary to seasonal variations in cell cycle progression. We investigated the impact of season of RT in two large, multi-institutional, prospective datasets of randomized trials.

METHODS

Individual patient data from the MACH-NC and MARCH meta-analyses were analyzed. Dark season was defined as mid-radiotherapy date during fall or winter and light the reverse, using equinoxes to separate the two periods. Primary endpoint was progression-free survival (PFS) and secondary endpoint was locoregional failure (LRF). The effect of season was estimated with a Cox model stratified by trial and adjusted on sex, tumor site, stage, and treatment. Planned sensitivity analyses were performed on patients treated around solstices, who received "complete radiotherapy", patients treated with concomitant radio-chemotherapy and on trials performed in Northern countries.

RESULTS

11320 patients from 33 trials of MARCH and 6276 patients from 29 trials of MACH-NC were included. RT during dark season had no benefit on PFS in the MARCH (hazard ratio[HR]: 1.01 [95%CI 0.97;1.05],p=0.72) or MACH-NC dataset (HR:1.00 [95%CI 0.94;1.06],p=1.0. No difference in LRF was observed in the MARCH (HR:1.00 [95%CI 0.94;1.06,p=0.95) or MACH-NC dataset (HR:0.99 [95%CI 0.91; 1.07],p=0.77). Sensitivity analyses showed similar results.

CONCLUSION

Season of RT had no impact on PFS or LRF in two large databases of HNSCC.

HYPORT: Phase 1 Study of 3-Week Hypofractionated Postoperative Radiation Therapy for Head and Neck Squamous Cell Carcinoma

PURPOSE

Shortening the overall radiation therapy (RT) treatment time has advantages in cost and treatment burden, but data on hypofractionated RT in head and neck squamous cell carcinoma are limited. This study assessed the safety of moderately hypofractionated RT in the postoperative setting.

METHODS AND MATERIALS

Patients with completely resected stage I-IVB squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx with intermediate risk factor(s) including T3/4 disease, positive lymph node(s), close margin(s), perineural invasion, and/or lymphovascular invasion were enrolled on a rolling 6-design phase 1 study. Levels 0 and 1 consisted of 46.5 Gy in 15 fractions delivered 5 days a week and 44.4 Gy in 12 fractions delivered 4 days a week, respectively. The primary endpoint was maximum tolerated dose/fractionation of moderately hypofractionated postoperative RT.

RESULTS

Twelve patients were enrolled with 6 each on levels 0 and 1. No patient experienced a dose-limiting toxicity or grade 4 to 5 toxicity. Acute grade 3 toxicity occurred in 2 patients on level 0 (weight loss, neck abscess) and 3 patients on level 1 (all oral mucositis). One patient on level 0 experienced late grade 3 toxicity (persistent neck abscess). With a median follow-up of 18.6 months, 2 patients on level 1 had a recurrence: a regional recurrence in the undissected, unirradiated contralateral neck from a well-lateralized tonsil primary and an in-field local recurrence of oral tongue primary. The maximum tolerated dose/fractionation was determined to be 44.4 Gy in 12 fractions, but owing to more favorable tolerability in the setting of equivalent biologically effective dose, 46.5 Gy in 15 fractions was deemed the recommended phase 2 dose/fractionation.

CONCLUSIONS

Moderately hypofractionated RT delivered over 3 weeks is well tolerated in the short term in this phase 1 cohort of patients with head and neck squamous cell carcinoma following surgical resection. The follow-up phase 2 randomized trial will deliver 46.5 Gy in 15 fractions as the experimental arm.

Assessment of residual geometrical errors of clinical target volumes and their impact on dose accumulation for head and neck radiotherapy

PURPOSE

To assess the residual geometrical errors (dr) and their impact on the clinical target volumes (CTV) dose coverage for head and neck cancer (HNC) proton therapy patients.

METHODS

We analysed 28 HNC patients treated with 70 Gy (RBE) and 54.25 Gy (RBE) to the therapeutic CTV70 and prophylactic CTV54.25, respectively. Daily cone beam CTs were converted to high quality synthetic CTs (sCTs). The CTVs from the nominal CT were propagated to the corresponding sCTs using a hybrid deformable image registration (propagated CTVs) in RayStation 11B. For 11 patients, all propagated CTVs were reviewed by our HNC radiation oncologist (physician corrected CTVs). The residual geometrical error dr was quantified as a function of the daily CTVs volume overlap with the nominal plan CTV. The errors dr(propagated CTVs) and dr(physician corrected CTVs) and the difference in dice similarity coefficients (ΔDSC) were determined. Using clinical plans, dose coverage and the tumor control probability (TCP) for the nominal, accumulated and voxel-wise minimum scenarios were determined.

RESULTS

The difference in the residual geometrical error dr (propagated CTVs - physician corrected CTVs) and mean DSC (|ΔDSC|mean) were minor: Δdr(CTV70) = 0.16 mm, Δdr(CTV54.25) = 0.26 mm, |ΔDSC|mean < 0.9%. For all 28 patients, dr(CTV70) = 1.91 mm and dr(CTV54.25) = 1.90 mm. However, CTV54.25 above and below the cricoid cartilage differed substantially (1.00 mm c.f. 3.93 mm). The CTV54.25 coverage below the cricoid was then almost always lower, although the TCP of the accumulated dose was higher than the TCP of the voxel-wise minimum dose.

CONCLUSIONS

Setup uncertainty setting of 2 mm is possible. The feasibility of using propagated CTVs for error determination is demonstrated.

Activation of gelatinases in permanent human teeth after different experimental radiotherapy protocols

The objective of this study was to compare the activation of gelatinases in dentin-enamel junction (DEJ) and underlying dentin of permanent teeth after experimental radiotherapy in conventional and hypofractionated modalities. Newly extracted third molars (n = 15) were divided into three experimental radiotherapy groups: control, conventional (CR), and hypofractionated (HR) (n = 5 per group). After in vitro exposure to ionizing radiation, following standardized protocols for each modality, a gelatinous substrate was incubated on the tooth slices (n = 10 per group). Activation of gelatinases was measured by in situ zymography, expressed in arbitrary fluorescence units (mm2) from three tooth regions: cervical, cuspal, and pit. Fluorescence intensity was compared among radiotherapy protocols and tooth regions in each protocol, considering a significance level of 5%. Considering all tooth regions, the fluorescence intensity of the CR group was higher than the HR and control groups, both in DEJ and underlying dentin (p <0.001). In addition, the fluorescence intensity was higher in underlying dentin when compared to DEJ in all groups (p <0.001). Considering each tooth region, a statistically significant difference between CR and HR was only observed in the pit region of underlying dentin (p <0.001). Significant and positive correlations between fluorescence intensities in DEJ and underlying dentin were also observed (p <0.001). Experimental radiotherapy influenced the activation of gelatinases, as well as exposure to the conventional protocol can trigger a higher activation of gelatinases when compared to hypofractionated, both in DEJ and underlying dentin.

Adaptive FDG-PET/CT guided dose escalation in head and neck squamous cell carcinoma: Late toxicity and oncologic outcomes (The ADMIRE study)

Purpose

To report on the late toxicity and local control (LC) of head and neck cancer patients treated with adaptive FDG-PET/CT response-guided radiotherapy (ADMIRE) with dose escalation (NCT03376386).

Materials and methods

Between December 2017 and April 2019, 20 patients with stage II-IV squamous cell carcinoma of the larynx, hypopharynx or oropharynx were treated within the ADMIRE study where FDG-PET/CT response-guided (Week 2&4) dose escalation was applied (total dose 70-78 Gy). Cisplatin or cetuximab was added to radiotherapy in case of T3-4 and/or N2c disease. To compare the LC and late toxicity of the study population, we used an external control group (n = 67) consisting of all eligible patients for the study (but not participated). These patients were treated in our institution during the same period with the current standard of 70 Gy radiotherapy. To reduce the effect of confounding, logistic regression analyses was done using stabilized inverse probability of treatment weighting (SIPTW).

Results

After median follow-up of 40 and 43 months for the ADMIRE and control groups, the 3-year LC-rates were 74% and 78%, respectively (adjusted HR after SIPTW 0.80, 95 %CI 0.25-2.52, p = 0.70). The incidences of any late G3 toxicity were 35% and 18%, respectively. The adjusted OR for any late G3 toxicity was 5.09 (95 %CI 1.64-15.8, p = 0.005), for any late G ≥ 2 toxicity was 3.67 (95 %CI 1.2-11.7, p = 0.02), for persistent laryngeal edema was 10.95 (95% CI 2.71-44.29, p = 0.001), for persistent mucosal ulcers was 4.67 (95% CI 1.23-17.7, p = 0.023), and for late G3 radionecrosis was 15.69 (95 %CI 2.43-101.39, p = 0.004).

Conclusion

Given the comparable LC rates with increased late toxicity in the ADMIRE group, selection criteria for future adaptive dose escalation trials (preferably randomized) need to be refined to include only patients at higher risk of local failure and/or lower risk of severe late toxicity.

Importance of tumor volume, overall treatment time and fractionation sensitivity for p16-positive and p16-negative oropharyngeal tumors

BACKGROUND

Analyses of clinical outcomes following radiotherapy (RT) have advanced our understanding of fundamental radiobiological characteristics in head and neck squamous cell carcinoma (HNSCC). Low fractionation sensitivity appears to be a common feature, as well as susceptibility to changes in overall treatment time (OTT). Large tumors should be harder to cure if a successful RT requires the sterilization of all clonogenic cells. Congruently, primary tumor volume has proven to be an important parameter. However, most findings come from an era when p16-negative HNSCC was the dominant tumor type. HPV-associated, p16-positive, oropharyngeal tumors (OPSCC) are more radiosensitive and have better outcome. The current study aims to investigate the role of primary tumor volume, OTT and estimate α/ β -ratio for p16-positive OPSCC, and to quantify the differences in radiosensitivity depending on p16-status.

METHODS

A cohort of 523 patients treated with RT was studied using a tumor control probability (TCP)-model that incorporates primary tumor volume (V) raised to an exponent c, OTT and α/ β -estimation. The significance of V was also investigated in Cox-regression models.

RESULTS

In the p16-positive cohort (n = 433), the volume exponent c was 1.44 (95%CI 1.06-1.91), compared to 0.90 (0.54-1.32) for p16-negative tumors (n = 90). Hazard ratios per tumor volume doubling were 2.37 (1.72-3.28) and 1.83 (1.28-2.62) for p16-positive and p16-negative, respectively. The estimated α/ β -ratio was 9.7 Gy (-2.3-21.6), and a non-significant daily loss of 0.30 Gy (-0.17-0.92) was found. An additional dose of 6.8 Gy (interquartile range 4.8-9.1) may theoretically counteract the more radioresistant behavior of p16-negative tumors.

CONCLUSION

Primary tumor volume plays a crucial role in predicting local tumor response, particularly in p16-positive OPSCC. The estimated α/β-ratio for p16-positive oropharyngeal tumors aligns with previous HNSCC studies, whereas the impact of prolonged OTT was slightly less than previously reported. The differences in radiosensitivity depending on p16-status were quantified. The findings should be validated in independent cohorts.