A dose escalation study with intensity modulated radiation therapy (IMRT) in T2N0, T2N1, T3N0 squamous cell carcinomas (SCC) of the oropharynx, larynx and hypopharynx using a simultaneous integrated boost (SIB) approach

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.

Effect of definitive hypo-fractionated radiotherapy concurrent with weekly cisplatin in locally advanced squamous cell carcinoma of the head and neck

To mitigate the risk of COVID-19 infection in cancer patients, it is recommended to utilize hypo-fractionated treatment schedules that aim to minimize the overall duration of treatment. In this study, we aimed to determine whether hypo-fractionated intensity-modulated radiotherapy (hypo-IMRT) with concurrent chemotherapy was practical, effective, and could achieve acceptable tumor control rates for squamous cell carcinoma of the head and neck (SCCHN). We enrolled 62 patients with high-risk stage II, stage III, and IVA SCCHN who received hypo-IMRT (62.5 Gy in 25 fractions over 5 weeks 2.5Gy/fraction with weekly cisplatin 40 mg/m²). Our primary endpoint was to assess acute toxicity, while our secondary endpoints were late toxicity, loco-regional control, disease-free survival, and overall survival. The percentages of grade 3 acute pain, dermatitis, mucositis, and dysphagia were 71%, 19.4%, 72.6%, and 41.9%, respectively. The rates of late xerostomia, dysphagia, dental complications, grade 3 pain, and grade 3 weight loss were 72.6%, 62.9%, 27.4%, 4.8%, and 4.3%, respectively. At a median follow-up time of 24 months, 2-year loco-regional control and overall survival were 87.1% and 83.9%, respectively. Disease-free survival was 100%, 89.5%, and 69% in stages II, III, and IV%, respectively, with a significant p-value of 0.024. This regimen was effective and relatively safe, with acceptable and tolerable acute and late toxicity. Given the reduced need for hospital visits, hypo-fractionated schedules may represent an alternative treatment during the COVID-19 outbreak.

Dose Escalation of Oropharyngeal Cancer: Long-Time Follow-Up and Side Effects

Previous studies on dose-escalated radiotherapy in head and neck cancer have shown mixed results, and it is not established which patients would benefit from dose escalation. Further, while dose escalation does not appear to increase late toxicity, this needs to be confirmed with longer follow-up. In this study, we analysed treatment outcome and toxicity in 215 patients with oropharyngeal cancer treated with dose-escalated radiotherapy (>72 Gy, EQD2, α/β = 10 Gy, boost by brachytherapy or simultaneous integrated boost) and a matched cohort of 215 patients treated with standard dose external-beam radiotherapy (68 Gy) between 2011 and 2018 at our institution. The 5-year overall survival (OS) was 77.8% (72.4-83.6) and 73.7% (67.8-80.1) in the dose-escalated and standard dose group, respectively (p = 0.24). Median follow-up was 78.1 (49.2-98.4) and 60.2 (38.9-89.4) months in the dose-escalated and standard dose groups, respectively. Grade ≥3 osteoradionecrosis (ORN) and late dysphagia were more common in the dose-escalated group compared to the standard dose group, with 19 (8.8%) vs. 4 (1.9%) patients developing grade ≥3 ORN (p = 0.001), and 39 (18.1%) vs. 21 (9.8%) patients developing grade ≥3 dysphagia (p = 0.01). No predictive factors to help select patients for dose-escalated radiotherapy were found. However, the remarkably good OS in the dose-escalated cohort, despite a predominance of advanced tumour stages, encourages further attempts to identify such factors.

Dose escalation in oropharyngeal cancer: a comparison of simultaneous integrated boost and brachytherapy boost

BACKGROUND

Local recurrence is the most common pattern of failure in head and neck cancer. It can therefore be hypothesised that some of these patients would benefit from an intensified local treatment, such as radiation dose escalation of the primary tumour. This study compares treatment and toxicity outcomes from two different boost modalities in oropharyngeal cancer: simultaneous integrated boost (SIB) and brachytherapy boost.

METHODS

Two hundred and forty-four consecutive patients treated with > 72 Gy for oropharyngeal squamous cell carcinoma between 2011 and 2018 at our institution were retrospectively analysed. Data on side effects were collected from a local quality registry and supplemented with a review of medical records. Patients receiving a brachytherapy boost first had external beam radiotherapy consisting of 68 Gy in 2 Gy fractions to the gross tumour volume (GTV), and elective radiotherapy to the neck bilaterally. The brachytherapy boost was typically given using pulsed dose rate, 15 fractions and 0.56-0.66 Gy per fraction [total dose in EQD2 = 75.4-76.8 Gy (α/β = 10)]. The typical dose escalated radiotherapy with external beam radiotherapy only, was delivered using SIB with 74,8 Gy in 2.2 Gy fractions [EQD2 = 76.0 Gy (α/β = 10)] to the primary tumour, 68 Gy in 2 Gy fractions to GTV + 10 mm margin and elective radiotherapy to the neck bilaterally.

RESULTS

Dose escalation by SIB was given to 111 patients and brachytherapy boost to 134 patients. The most common type of cancer was base of tongue (55%), followed by tonsillar cancer (42%). The majority of patients had T3- or T4-tumours and 84% were HPV-positive. The 5-year OS was 72,4% (95% CI 66.9-78.3) and the median follow-up was 6.1 years. Comparing the two different dose escalation modalities we found no significant differences in OS or PFS and these results remained after a propensity-score matched analysis was performed. The analysis of grade ≥ 3 side effects showed no significant differences between the two different dose escalation techniques.

CONCLUSIONS

We found no significant differences in survival or grade ≥ 3 side effects comparing simultaneous integrated boost and brachytherapy boost as alternative dose escalation modalities in the treatment of oropharyngeal cancer.

World Workshop on Oral Medicine VIII: Development of a Core Outcome Set for Dry Mouth: A Systematic Review of Outcome Domains for Xerostomia

OBJECTIVE

The purpose of this study was to identify all outcome domains used in clinical studies of xerostomia, that is, subjective sensation of dry mouth. This study is part of the extended project "World Workshop on Oral Medicine Outcomes Initiative for the Direction of Research" to develop a core outcome set for dry mouth.

STUDY DESIGN

A systematic review was performed on MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials databases. All clinical and observational studies that assessed xerostomia in human participants from 2001 to 2021 were included. Information on outcome domains was extracted and mapped to the Core Outcome Measures in Effectiveness Trials taxonomy. Corresponding outcome measures were summarized.

RESULTS

From a total of 34,922 records retrieved, 688 articles involving 122,151 persons with xerostomia were included. There were 16 unique outcome domains and 166 outcome measures extracted. None of these domains or measures were consistently used across all the studies. The severity of xerostomia and physical functioning were the 2 most frequently assessed domains.

CONCLUSION

There is considerable heterogeneity in outcome domains and measures reported in clinical studies of xerostomia. This highlights the need for harmonization of dry mouth assessment to enhance comparability across studies and facilitate the synthesis of robust evidence for managing patients with xerostomia.

Identifying the location of locoregional recurrences after definitive radiotherapy for head and neck cancer using metabolic parameters of baseline and mid-treatment 18F-FDG-PET scans

INTRODUCTION

Tumour recurrences after treatment of head and neck squamous cell carcinoma (HNSCC) are more likely to originate from regions of high-baseline FDG-PET uptake. Mid-treatment functional imaging can potentially predict for higher risk of tumour recurrence. The aim of this study is to correlate the location of locoregional tumour recurrence with baseline FDG-PET metabolic volumes and mid-treatment FDG-PET metabolic volumes in patients with HNSCC following definitive radiotherapy.

METHODS

A total of 23 patients with 26 local and/or regional recurrences underwent baseline (W0-PET) and mid-treatment (W3-PET) 18F-FDG PET scans as part of their radiotherapy. FDG-PET-based metabolic volumes (MTV20%, MTV40%, MTV60%, MTV80%, SUV2.5, SUVpeak and PET_EDGE) were delineated onto the FDG-PET scans. The recurrence nidus was identified on FDG-PET at the time of recurrence (REC-PET). DIR-based fusion was performed for REC-PET to W0-PET, and REC-PET to W3-PET. The location of the recurrence nidus was correlated with the FDG-PET volumes. Further analysis included a comparison of the recurrence density to FDG-PET metabolic volumes.

RESULTS

Most recurrences occurred within the MTV20%, MTV40% and SUV 2.5 volumes. Sixty-nine per cent of recurrences (18 of 26) occurred within both the W0 MTV40% and W3 MTV40% volumes. A higher recurrence density was seen for iso-SUV contours closer to the maximum SUV for both W0 and W3. For a number of the FDG-PET volumes, including MTV20%, MTV40% and SUV2.5, the recurrence density was improved for W3 compared to W0, however, this improvement was small in magnitude. The average volume of MTV40% contours was considerably smaller than MTV20% and SUV2.5 contours.

CONCLUSION

The metabolic parameters of SUV2.5, MTV20% and MTV40% delineated on the baseline and mid-treatment FDG-PET scans encompassed the majority of recurrences. The MTV40% is significantly smaller, hence, we prefer this volume for future dose escalation studies.

Dose escalation to hypoxic subvolumes in head and neck cancer: A randomized phase II study using dynamic [18F]FMISO PET/CT

BACKGROUND AND PURPOSE

Tumor hypoxia is a major cause of resistance to radiochemotherapy in locally advanced head-and-neck cancer (LASCCHN). We present results of a randomized phase II trial on hypoxia dose escalation (DE) in LASCCHN based on dynamic [¹⁸F]FMISO (dynFMISO) positron emission tomography (PET). The purpose was to confirm the prognostic value of hypoxia PET and assess feasibility, toxicity and efficacy of hypoxia-DE.

MATERIALS AND METHODS

Patients with LASCCHN underwent baseline dynFMISO PET/CT. Hypoxic volumes (HV) were derived from dynFMISO data. Patients with hypoxic tumors (HV>0) were randomized into standard radiotherapy (ST: 70Gy/35fx) or dose escalation (DE: 77Gy/35fx) to the HV. Patients with non-hypoxic tumors were treated with ST. After a minimum follow-up of 2 years, feasibility, acute/late toxicity and local control (LC) were analyzed.

RESULTS

The study was closed prematurely due to slow accrual. Between 2009 and 2017, 53 patients were enrolled, 39 (74%) had hypoxic tumors and were randomized into ST or DE. For non-hypoxic patients, 100% 5-year LC was observed compared to 74% in patients with hypoxic tumors (p=0.039). The difference in 5-year LC between DE (16/19) and ST (10/17) was 25%, p=0.150. No relevant differences related to acute and late toxicities between the groups were observed.

CONCLUSION

This study confirmed the prognostic value of hypoxia PET in LASCCHN for LC. Outcome after hypoxia DE appears promising and may support the concept of DE. Slow accrual and premature closure may partly be due to a high complexity of the study setup which needs to be considered for future multicenter trials.

Comparison of efficacy and safety between simultaneous integrated boost intensity-modulated radiotherapy and standard-dose intensity-modulated radiotherapy in locally advanced esophageal squamous cell carcinoma: a retrospective study

Objective

This study aimed to evaluate the efficacy and safety of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) versus standard-dose intensity-modulated radiotherapy (SD-IMRT) in the treatment of locally advanced esophageal squamous cell carcinoma.

Methods

From July 2003 to March 2014, 1748 patients in a single center who received definitive chemoradiotherapy were included in the analysis. A total of 109 patients who underwent SIB-IMRT and fulfilled all inclusion and exclusion criteria were identified as the study group. A total of 266 patients who underwent SD-IMRT (60 Gy/30 fractions, 2 Gy/fraction, 1 time/day, 5 times/week) during the same period were selected as the control group. Propensity score matching (PSM) was used to balance the baseline characteristics. Survival status, treatment failure mode, and the occurrence of adverse events were compared between the two groups.

Results

There were more women and more cervical and upper thoracic cancers (P = 0.038, < 0.001, respectively) in the SIB-IMRT group before case matching. The median progression-free survival (PFS) in the SD-IMRT and SIB-IMRT groups was 22 and 19 months, respectively, and the median overall survival duration was 24 and 22 months, respectively, with χ² = 0.244 and P = 0.621. After PSM of 1:1, 138 patients entered the final analysis (69 cases from each group). The median PFS of the SD-IMRT group and the SIB-IMRT group was 13 and 18 months, respectively, with χ² = 8.776 and P = 0.003. The 1‑, 3‑, and 5‑year overall survival rates were 66.7, 21.7, and 8.7% and 65.2, 36.2, and 27.3%, respectively, and the median overall survival duration was 16 and 22 months, respectively, with χ² = 5.362 and P = 0.021. Treatment failure mode: 5‑year local regional recurrence rates of SD-IMRT and SIB-IMRT were 50.7 and 36.2%, respectively, with χ² = 2.949 and P = 0.086. The 5‑year distant metastasis rates of the two groups were 36.2 and 24.6%, respectively, with χ² = 2.190 and P = 0.139. Adverse events: 3 patients experienced grade 4–5 toxicity (2.2%), including one case of grade 4 radiation esophagitis and two cases of grade 5 radiation pneumonitis, all in the SD-IMRT group; 14 patients experienced grade 3 adverse events (10.1%), primarily including radiation esophagitis, radiation pneumonitis, and hematological toxicity.

Conclusion

The technique of SIB-IMRT was safe and reliable compared with SD-IMRT. In addition, SIB-IMRT had locoregional control advantages and potential survival benefits.

Supplementary Information

The online version of this article (10.1007/s00066-021-01894-y) contains supplementary material, which is available to authorized users.

Definitive Simultaneous Integrated Boost Versus Conventional-Fractionated Intensity Modulated Radiotherapy for Patients With Advanced Esophageal Squamous Cell Carcinoma: A Propensity Score-Matched Analysis

BACKGROUND

The aim of this study was to compare the effects of simultaneous integrated boost-intensity modulated radiotherapy (SIB-IMRT) and conventional fractionated-IMRT (CF-IMRT) for patients with esophageal squamous cell carcinoma (ESCC).

METHODS

The data of 1173 patients treated with either CF-IMRT or SIB-IMRT for a curative intent from 2005 to 2016 were retrospectively reviewed. Propensity score matching (PSM) was used to create a well-balanced cohort of 687 patients at 1:2 ratio (237 patients in SIB-IMRT group and 450 patients in CF-IMRT group). Overall survival (OS), progression-free survival (PFS), recurrence pattern, and toxicity profiles were evaluated and compared between the two groups after PSM.

RESULTS

After a median follow-up time of 42.3 months (range, 3.0-153.2 months) for surviving patients, survival results were comparable in the two groups. After PSM, the 1-year, 2-year and 4-year OS rates in the SIB-IMRT and CF-IMRT groups were 70.0% vs. 66.4%, 41.9% vs. 41.7% and 30.2% vs. 27.6%, respectively (p = 0.87). The 1-year, 2-year and 4-year PFS rates were 48.4% vs. 49.1%, 31.2% vs. 29.4%, and 26.1% vs. 17.9%, respectively (p = 0.64). Locoregional recurrence (p = 0.32) and distant metastasis (p = 0.54) rates were also comparable between two groups. The toxicity profile was similar in the two groups. Multivariate analyses in the matched samples showed that female, concurrent chemotherapy and earlier clinical stage were independently associated with longer OS and PFS.

CONCLUSIONS

SIB-IMRT appears to be equivalent to CF-IMRT in treatment efficacy and safety, and could become an alternative option for definitive radiotherapy of ESCC.

Targeting Treatment Resistance in Head and Neck Squamous Cell Carcinoma - Proof of Concept for CT Radiomics-Based Identification of Resistant Sub-Volumes

Purpose

Radiomics has already been proposed as a prognostic biomarker in head and neck cancer (HNSCC). However, its predictive power in radiotherapy has not yet been studied. Here, we investigated a local radiomics approach to distinguish between tumor sub-volumes with different levels of radiosensitivity as a possible target for radiation dose intensification.

Materials and Methods

Of 40 patients (n=28 training and n=12 validation) with biopsy confirmed locally recurrent HNSCC, pretreatment contrast-enhanced CT images were registered with follow-up PET/CT imaging allowing identification of controlled (GTVcontrol) vs non-controlled (GTVrec) tumor sub-volumes on pretreatment imaging. A bi-regional model was built using radiomic features extracted from pretreatment CT in the GTVrec and GTVcontrol to differentiate between those regions. Additionally, concept of local radiomics was implemented to perform detection task. The original tumor volume was divided into sub-volumes with no prior information on the location of recurrence. Radiomic features from those sub-volumes were then used to detect recurrent sub-volumes using multivariable logistic regression.

Results

Radiomic features extracted from non-controlled regions differed significantly from those in controlled regions (training AUC = 0.79 CI 95% 0.66 - 0.91 and validation AUC = 0.88 CI 95% 0.72 – 1.00). Local radiomics analysis allowed efficient detection of non-controlled sub-volumes both in the training AUC = 0.66 (CI 95% 0.56 – 0.75) and validation cohort 0.70 (CI 95% 0.53 – 0.86), however performance of this model was inferior to bi-regional model. Both models indicated that sub-volumes characterized by higher heterogeneity were linked to tumor recurrence.

Conclusion

Local radiomics is able to detect sub-volumes with decreased radiosensitivity, associated with location of tumor recurrence in HNSCC in the pre-treatment CT imaging. This proof of concept study, indicates that local CT radiomics can be used as predictive biomarker in radiotherapy and potential target for dose intensification.

Moderately accelerated intensity-modulated radiation therapy using simultaneous integrated boost: Practical reasons or evidence-based choice? A critical appraisal of literature

Concurrent chemo-radiotherapy is the non-surgical mainstay of treatment for locally advanced head and neck squamous cell carcinoma (HNSCC). The following aspects have emerged as fundamental components of the combined approach: first, intensity modulated radiotherapy (IMRT) is the minimum standard technical requirement, with level 1 evidence in support of its reduction of late treatment-induced morbidity in comparison with 3D conformal radiotherapy. Second, cisplatin-based chemotherapy is the preferred systemic agent to be associated with radiation, with 100 mg/m² every 3 weeks deemed as the reference schedule. Because of significant progress in irradiation techniques achieved in last 15 years, the optimal fractionation schedule in modern radiation era remains controversial, especially for locally advanced disease. The purpose of this work was to perform a critical review on the value of moderately accelerated IMRT using simultaneous-integrated boost (SIB) in HNSCC, aiming to provide insights on current clinical practice and directions for future research.

Correlation Between FDG Hotspots on Pre-radiotherapy PET/CT and Areas of HNSCC Local Relapse: Impact of Treatment Position and Images Registration Method

Aim: Several series have already demonstrated that intratumoral subvolumes with high tracer avidity (hotspots) in 18F-flurodesoxyglucose positron-emission tomography (FDG-PET/CT) are preferential sites of local recurrence (LR) in various solid cancers after radiotherapy (RT), becoming potential targets for dose escalation. However, studies conducted on head and neck squamous cell carcinoma (HNSCC) found only a moderate overlap between pre- and post-treatment subvolumes. A limitation of these studies was that scans were not performed in RT treatment position (TP) and were coregistred using a rigid registration (RR) method. We sought to study (i) the influence of FDG-PET/CT acquisition in TP and (ii) the impact of using an elastic registration (ER) method to improve the localization of hotpots in HNSCC.

Methods: Consecutive patients with HNSCC treated by RT between March 2015 and September 2017 who underwent FDG-PET/CT in TP at initial staging (PET_A) and during follow-up (PET_R) were prospectively included. We utilized a control group scanned in non treatment position (NTP) from our previous retrospective study. Scans were registered with both RR and ER methods. Various sub-volumes (A_X; x = 30, 40, 50, 60, 70, 80, and 90%SUVmax) within the initial tumor and in the subsequent LR (R_X; x = 40 and 70%SUVmax) were overlaid on the initial PET/CT for comparison [Dice, Jaccard, overlap fraction = OF, common volume/baseline volume = A_XnR_X/A_X, common volume/recurrent volume = A_XnR_X/R_X].

Results: Of 199 patients included, 43 (21.6%) had LR (TP = 15; NTP = 28). The overlap between A₃₀, A₄₀, and A₅₀ sub-volumes on PET_A and the whole metabolic volume of recurrence R₄₀ and R₇₀ on PET_R showed moderate to good agreements (0.41–0.64) with OF and A_XnR_X/R_X index, regardless of registration method or patient position. Comparison of registration method demonstrated OF and A_XnR_X/R_X indices (x = 30% to 50%SUVmax) were significantly higher with ER vs. RR in NTP (p < 0.03), but not in TP. For patient position, the OF and A_XnR_X/R_X indices were higher in TP than in NTP when RR was used with a trend toward significance, particularly for x=40%SUVmax (0.50±0.22 vs. 0.31 ± 0.13, p = 0.094).

Conclusion: Our study suggested that PET/CT acquired in TP improves results in the localization of FDG hotspots in HNSCC. If TP is not possible, using an ER method is significantly more accurate than RR for overlap estimation.

Molecular mechanisms underlying increased radiosensitivity in human papillomavirus-associated oropharyngeal squamous cell carcinoma

Oropharyngeal squamous cell carcinoma (OPSCC) is an important type of head and neck squamous cell carcinoma (HNSCC). The traditional risk factors for OPSCC include carcinogen intake, smoking, alcohol consumption, and lifestyle. In recent years, cases of human papillomavirus (HPV)-related OPSCC have gradually increased. At present, HPV-related OPSCC in developed Western countries comprise up to 90% of all OPSCC cases, while in other developing countries, the proportion of HPV-related OPSCC cases is also gradually increasing. Compared with HPV-negative OPSCC, HPV-positive OPSCC patients have better overall survival rates and local control rates and this improved prognosis may be related to the increased radiosensitivity of HPV-positive tumors. Due to this more favorable prognosis, many downgraded treatment schemes are gradually emerging, including simple radiotherapy instead of concurrent radiotherapy or reduced radiotherapy dose. However, there is insufficient theoretical basis for such schemes. Some studies have shown that delayed repair of DNA damage after radiation, G2/M arrest, increased hypoxia, and decreased proliferation capacity are the main reasons for the increased radiosensitivity of HPV-positive tumor cells. In this review, we discuss the four principles of tumor cell damage caused by radiation, including repair, reoxygenation, redistribution, and regeneration in order to reveal the mechanism whereby HPV increases the radiosensitivity of tumor cells. An attempt was made to provide sufficient information to facilitate more individualized treatment for HPV-positive OPSCC patients, under the premise of good tumor control.

A Review of Modern Radiation Therapy Dose Escalation in Locally Advanced Head and Neck Cancer

The management of head and neck cancer is complex and often involves multimodality treatment. Certain groups of patients, such as those with inoperable or advanced disease, are at higher risk of treatment failure and may therefore benefit from radiation therapy dose escalation. This can be difficult to achieve without increasing toxicity. However, the combination of modern treatment techniques and increased research into the use of functional imaging modalities that assist with target delineation allows researchers to push this boundary further. This review aims to summarise modern dose escalation trials to identify the impact on disease outcomes and explore the growing role of functional imaging modalities. Studies experimenting with dose escalation above standard fractionated regimens as outlined in National Comprehensive Cancer Network guidelines using photon therapy were chosen for review. Seventeen papers were considered suitable for inclusion in the review. Eight studies investigated nasopharyngeal cancer, with the remainder treating a range of subsites. Six studies utilised functional imaging modalities for target delineation. Doses as high as 85.9 Gy in 2.6 Gy fractions (EQD2 90.2 Gy₁₀) were reportedly delivered with the aid of functional imaging modalities. Dose escalation in nasopharyngeal cancer resulted in 3-year locoregional control rates of 86.6-100% and overall survival of 82-95.2%. For other mucosal primary tumour sites, 3-year locoregional control reached 68.2-85.9% and 48.4-54% for overall survival. There were no clear trends in acute or late toxicity across studies, regardless of dose or addition of chemotherapy. However, small cohort sizes and short follow-up times may have resulted in under-reporting. This review highlights the future possibilities of radiation therapy dose escalation in head and neck cancer and the potential for improved target delineation with careful patient selection and the assistance of functional imaging modalities.

Using biologically based objectives to optimize boost intensity-modulated radiation therapy planning for brainstem tumors in dogs

Irradiated brain tumors commonly progress at the primary site, generating interest in focal dose escalation. The aim of this retrospective observational study was to use biological optimization objectives for a modeling exercise with simultaneously-integrated boost IMRT (SIB-IMRT) to generate a dose-escalated protocol with acceptable late radiation toxicity risk estimate and improve tumor control for brainstem tumors in dogs safely. We re-planned 20 dog brainstem tumor datasets with SIB-IMRT, prescribing 20 × 2.81 Gy to the gross tumor volume (GTV) and 20 × 2.5 Gy to the planning target volume. During the optimization process, we used biologically equivalent generalized equivalent uniform doses (gEUD) as planning aids. These were derived from human data, calculated to adhere to normal tissue complication probability (NTCP) ≤5%, and converted to the herein used fractionation schedule. We extracted the absolute organ at risk dose-volume histograms to calculate NTCP of each individual plan. For planning optimization, gEUD(a = 4)  = 39.8 Gy for brain and gEUD(a = 6.3)  = 43.8 Gy for brainstem were applied. Mean brain NTCP was low with 0.43% (SD ±0.49%, range 0.01-2.04%); mean brainstem NTCP was higher with 7.18% (SD ±4.29%, range 2.87-20.72%). Nevertheless, NTCP of < 10% in brainstem was achievable in 80% (16/20) of dogs. Spearman's correlation between relative GTV and NTCP was high (ρ = 0.798, P < .001), emphasizing increased risk with relative size even with subvolume-boost. Including biologically based gEUD values into optimization allowed estimating NTCP during the planning process. In conclusion, gEUD-based SIB-IMRT planning resulted in dose-escalated treatment plans with acceptable risk estimate of NTCP < 10% in the majority of dogs with brainstem tumors. Risk was correlated with relative tumor size.

Treatment Strategy for Distant Synchronous Metastatic Head and Neck Squamous Cell Carcinoma

PURPOSE OF REVIEW

Management of metastatic head and neck squamous cell cancers (HNSCC) can be challenging. This review gives an insight of current treatment options for patients with synchronous metastatic HNSCC and suggests a therapeutic algorithm.

RECENT FINDINGS

With the rise of novel therapeutic techniques and medications, many treatment options for both locoregional and distant metastatic disease have become available. The evolving paradigm of metastatic disease now integrates the concept of oligometastatic disease. On top of systemic treatments, patients with low metastatic burden can benefit from curative approaches such as local therapies (surgery, radiotherapy) directed to either primary tumour and distant metastasis. However, data integrating these considerations in the management of metastatic HNSCC is still lacking. Based on this algorithm, we can provide a tailored treatment to each patient with synchronous metastatic HNSCC, according to their age, general condition and metastatic burden.

A comparison of clinical outcomes between simultaneous integrated boost (SIB) versus sequential boost (SEQ) intensity modulated radiation therapy (IMRT) for head and neck cancer: A meta-analysis

BACKGROUND

The optimal intensity modulated radiation therapy (IMRT) technique for head and neck cancer (HNC) has not been determined yet. The present study aimed to compare the clinical outcomes of the simultaneous integrated boost (SIB)-IMRT versus the sequential boost (SEQ)-IMRT in HNC.

METHODS

A meta-analysis of 7 studies involving a total of 1049 patients was carried out to compare the treatment outcomes together with severe acute adverse effects of the SIB-IMRT versus the SEQ-IMRT in HNC patients.

RESULTS

Comparison of the SIB-IMRT and SEQ-IMRT showed no significant difference in the measurement of overall survival (OS) (hazard ratio [HR] 0.94; 95% confidence inerval [CI], 0.70-1.27; P = .71), progression free survival (PFS) (HR 1.03; 95% CI, 0.82-1.30; P = .79), locoregional recurrence free survival (LRFS) (HR 0.98; 95% CI, 0.65-1.47; P = .91), and distance metastasis free survival (DMFS) (HR 0.87; 95% CI, 0.50-1.53; P = .63). Moreover, there were no significant differences in adverse effect occurrence between the SIB-IMRT and SEQ-IMRT groups.

CONCLUSION

SIB-IMRT and SEQ-IMRT can provide comparable outcomes in the treatment of patients afflicted by HNC. Both IMRT techniques were found to carry a similar risk of severe acute adverse effect. SIB-IMRT may have advantages due to its convenience and short-course of treatment; however, the optimum fractionation and prescribed dose remained unclear. Furthermore, both IMRT techniques can be advocated as the technique of choice for HNC. Treatment plan should be individualized for patients.

Hypofractionated radiotherapy for early glottic cancer: a retrospective interim analysis of a single institution

PURPOSE

To evaluate the results of hypofractionated radiotherapy (HFX) for early glottic cancer.

MATERIALS AND METHODS

Eighty-five patients with cT1-2N0M0 squamous cell carcinoma of the glottis who had undergone HFX, performed using intensity-modulated radiotherapy (IMRT, n = 66) and three-dimensional conformal radiotherapy (3D CRT, n = 19) were analyzed. For all patients, radiotherapy was administered at 60.75 Gy in 27 fractions. Forty-three patients received a simultaneous integrated boost (SIB) of 2.3-2.5 Gy per tumor fraction.

RESULTS

The median follow-up duration was 29.9 months (range, 5.5 to 76.5 months). All patients achieved complete remission at a median of 50 days after the end of radiotherapy (range, 14 to 206 days). The 5-year rates for locoregional recurrence-free survival was 88.1%, and the 5-year overall survival rate was 86.2%. T2 stage was a prognostic factor for locoregional recurrencefree survival after radiotherapy (p = 0.002). SIB for the tumor did not affect disease control and survival (p = 0.191 and p = 0.387, respectively). No patients experienced acute or chronic toxicities of ≥grade 3. IMRT significantly decreased the dose administered to the carotid artery as opposed to 3D CRT (V35, p < 0.001; V50, p < 0.001).

Conclusions

Patients treated with HFX achieved acceptable locoregional disease control rates and overall survival rates compared with previous HFX studies. A fraction size of 2.25 Gy provided good disease control regardless of SIB administration.

Oropharyngeal Cancers in the East and the West - Implications of Aetiopathogenesis on Prognosis and Research

There has been a surge in human papillomavirus (HPV)-positive oropharyngeal cancers (OPCs) in the West. Although the prognosis of HPV-positive OPC is good, de-escalation strategies have so far not been able to confirm comparable cancer control. We examine the strategies implemented across the globe to safely reduce toxicities in HPV-positive disease. HPV-negative OPC has a poorer prognosis and is more prevalent in Eastern countries. We outline the intensification strategies currently used in HPV-negative cancers, with an aim to better prognosis. With recent improvements in clinical trial frameworks in Eastern countries such as India, we discuss areas where joint collaborative research between Western and Eastern countries could further improve outcomes in OPC.

Paediatric virology and human papillomaviruses: An update

Almost 10 years ago, in October, 2008, the scientist who reported for the first time the association between human papillomaviruses (HPV) and cervical cancer, was awarded with the Nobel prize. In the years that followed, Professor Harald zur Hausen actively supported the value of the HPV vaccination in the prevention of different types of cancer and highlighted the necessity of its introduction in both girls and boys. However, to date, in the majority of countries, HPV vaccination among male adolescents has not been implemented into the national vaccination schemes, while in several countries, including Greece, the participation rate to HPV vaccination among female adolescents still remains low. Recent data indicate that catch-up HPV vaccination among young women has been extremely useful and has exhibited a significant effect in decreasing the prevalence of HPV. While the marketed current HPV vaccines prevent anogenital HPV infection, their impact on the natural history of oral HPV and their efficacy in preventing HPV-related head and neck carcinomas need to be further investigated. Juvenile onset recurrent respiratory papillomatosis, as well as HPV-associated conjunctival papillomas continue to be observed in childhood and their clinical management involves different therapeutic approaches with controversial outcomes. This review article provides an overview of recent views and advances on HPV infections and prevention in childhood that were presented at the '4th Workshop on Paediatric Virology' on Saturday September 22, 2018 in Athens, Greece.

Comparison between hypo-fractionated dose-escalated volumetric modulated arc therapy and conventional concurrent chemo-radiation in locally advanced head and neck cancer: a pilot study

Objective:

In the treatment of locally advanced head and neck cancer (LA-HNC), both dose escalation and hypo-fractionation can improve tumour control rates with uncertain role of addition of concurrent chemotherapy. We aimed at developing a new radiotherapy protocol for patients not eligible to receive the standard concurrent chemo-radiation therapy (CCRT) with little toxicity profile.

Methods:

A total of 63 LA-HNC patients were randomised to receive either: 70 Gy in 35 fx in 7 weeks concurrently with cisplatin 100 mg/m2 every 3 weeks for 3 doses (Arm A) or 74 Gy in 33 fx in 6·5 weeks (Arm B). Volumetric modulated arc therapy plans were created for both treatment arms. We compared the local control (LC), progression-free survival (PFS), overall survival (OS) and acute and late toxicity between the two arms.

Results:

A total of 33 patients were in Arm A versus 30 patients in Arm B with median follow-up 24·2 months. No significant differences in LC, PFS and OS between the two arms. Complete remission occurred in 54·5 and 63·3% of patients in Arms A and B, respectively. All toxicities were significantly less in Arm B than Arm A.

Conclusion:

Slightly dose-escalated hypo-fractionated regimen is safe and feasible and has comparable efficacy and less acute and late side effects than conventional dose CCRT with avoidance of chemotherapy-related toxicities in LA-HNC patients.

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

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

Dose dependence of accelerated repopulation in head and neck cancer: Supporting evidence and clinical implications

BACKGROUND AND PURPOSE

Accelerated repopulation (AR) can compromise tumor control after conventional radiotherapy for fast-growing tumors. Standard AR models assume it begins at a fixed time, with repopulation rates independent of the number of clonogens killed. We investigate the validity and significance of an alternative model where onset-time and rate of AR depend on the number of clonogens killed, and thus on dose and dose-fractionation.

MATERIALS AND METHODS

We analyzed tumor control (TCP) from randomized trials for head and neck cancer (HNC, 7283 patients), featuring wide ranges of doses, times, and fractionation-schemes. We used the linear-quadratic model with the standard dose-independent AR model, or with an alternative dose-dependent model, where AR onset and rate depend on clonogen killing.

RESULTS

The alternative dose-dependent model of AR provides significantly-improved descriptions of a wide range of randomized clinical data, relative to the standard dose-independent model. This preferred model predicts that, for currently-used HNC fractionation schemes, the last 5 fractions do not increase TCP, but simply compensate for increased accelerated repopulation.

CONCLUSIONS

The preferred dose-dependent AR model predicts that, for standard fractionation schemes currently used to treat HNC, the final week (5 fractions) could be eliminated without compromising TCP, but resulting in significantly decreased late sequelae due to the lower overall dose.

Implementation of a rapid learning platform: Predicting 2-year survival in laryngeal carcinoma patients in a clinical setting

Background and Purpose

To improve quality and personalization of oncology health care, decision aid tools are needed to advise physicians and patients. The aim of this work is to demonstrate the clinical relevance of a survival prediction model as a first step to multi institutional rapid learning and compare this to a clinical trial dataset.

Materials and Methods

Data extraction and mining tools were used to collect uncurated input parameters from Illawarra Cancer Care Centre's (clinical cohort) oncology information system. Prognosis categories previously established from the Maastricht Radiation Oncology (training cohort) dataset, were applied to the clinical cohort and the radiotherapy only arm of the RTOG-9111 (trial cohort).

Results

Data mining identified 125 laryngeal carcinoma patients, ending up with 52 patients in the clinical cohort who were eligible to be evaluated by the model to predict 2-year survival and 177 for the trial cohort. The model was able to classify patients and predict survival in the clinical cohort, but for the trial cohort it failed to do so.

Conclusions

The technical infrastructure and model is able to support the prognosis prediction of laryngeal carcinoma patients in a clinical cohort. The model does not perform well for the highly selective patient population in the trial cohort.

Radiotherapy for esophageal carcinoma: dose, response and survival

Esophageal cancer (EC) is an extremely aggressive, lethal malignancy that is increasing in incidence worldwide. At present, definitive chemoradiotherapy is accepted as the standard treatment for locally advanced EC. The EC guidelines recommend a radiation dose of 50.4 Gy for definitive treatment, yet the outcomes for patients who have received standard-dose radiotherapy remain unsatisfactory. However, some studies indicate that a higher radiation dose could improve local tumor control, and may also confer survival benefits. Some studies, however, suggest that high-dose radiotherapy does not bring survival benefit. The available data show that most failures occurred in the gross target volume (especially in the primary tumor) after definitive chemoradiation. Based on those studies, we hypothesize that at least for some patients, more intense local therapy may lead to better local control and survival. The aim of this review is to evaluate the radiation dose, fractionation strategies, and predictive factors of response to therapy in functional imaging for definitive chemoradiotherapy in esophageal carcinoma, with an emphasis on seeking the predictive model of response to CRT and trying to individualize the radiation dose for EC patients.

Analysis of CT-verified loco-regional recurrences after definitive IMRT for HNSCC using site of origin estimation methods

INTRODUCTION

A significant part of patients with head and neck squamous cell carcinoma (HNSCC) develop recurrent disease after curative radiotherapy. We aimed to analyze loco-regional recurrence pattern by identifying possible points of recurrence origin by three different methods in relation to treatment volumes.

MATERIAL AND METHODS

A total of 455 patients completed IMRT-based treatment for HNSCC from 2006 to 2012. A total of 159 patients had remaining cancer after IMRT, developed loco-regional recurrence or distant disease during follow-up. Among those, 69 patients with loco-regional recurrences had affirmative CT or PET/CT scan. Possible points of origin (POs) of the recurrences were identified on scans by two independent observers, estimated as center of mass and as maximum surface distance. The recurrence position was analyzed in relation to high-dose treatment volume (CTV1) and 95% of prescription dose.

RESULTS

In total, 104 loco-regional recurrences (54 in T-site and 50 in N-site) were identified in 69 patients. Median time to recurrence for the 69 patients was 10 months. No clinically relevant difference was found between the four POs, with standard deviation between POs in x, y and z axes of 3, 3 and 6 mm. For recurrences inside CTV1, 0-5 mm and 5-10 mm outside CTV1 the standard deviation of dose differences between the POs were 1, 1.4 and 1 Gy, respectively. 56% and 25% of T-site and N-site recurrences were inside CTV1, respectively. Coverage by 95% prescription dose to high-dose treatment volume was achieved in 78% of T-site and 39% of N-site recurrences.

CONCLUSIONS

For recurrences identified by possible points of recurrence origin, no significant difference between observer-based or mathematically estimated methods was found. More than half of T-site recurrences were inside high-dose treatment volume, whereas N-site recurrences were mainly outside.

Long-term outcome of 18 F-fluorodeoxyglucose-positron emission tomography-guided dose painting for head and neck cancer: Matched case-control study

BACKGROUND

The purpose of this study was to report the long-term outcome of ¹⁸ F-fluorodeoxyglucose-positron emission tomography (¹⁸ F-FDG-PET)-guided dose painting for head and neck cancer in comparison to conventional intensity-modulated radiotherapy (IMRT) in a matched case-control study.

METHODS

Seventy-two patients with nonmetastatic head and neck cancer treated with dose painting were compared with 72 control patients matched on tumor site and T classification. Either ¹⁸ F-FDG-PET-guided dose painting by contour (DPBC) or voxel intensity-based dose painting by number (DPBN) was performed; control patients underwent standard IMRT. A total median dose to the dose-painted target was 70.2-85.9 Gy/30-32 fractions versus 69.1 Gy/32 fractions with conventional IMRT. In 31 patients, dose painting was adapted to per-treatment changes in the tumor and organs-at-risk (OAR).

RESULTS

Median follow-up in living dose-painting and control patients was 87.7 months (range 56.1-119.3) and 64.8 months (range 46.3-83.4), respectively. Five-year local control rates in the dose-painting patients were 82.3% against 73.6% in the control (P = .36); in patients treated to normalized isoeffective doses >91 Gy (NID2Gy) local control reached 85.7% at 5 years against 73.6% in the control group (P =.39). There was no difference in regional (P = .82) and distant control (P = .78). Five-year overall and disease-specific survival rates were 36.3% versus 38.1% (P = .50) and 56.5% versus 51.7% (P = .72), respectively. A half of the dose-painting patients developed acute grade ≥3 dysphagia (P = .004). Late grade 4 mucosal ulcers at the site of dose escalation in 9 of 72 patients was the most common severe toxicity with dose painting versus 3 of 72 patients with conventional IMRT (P = .11). Patients in the dose-painting group had increased rates of acute and late dysphagia (P = .004 and P = .005).

CONCLUSION

Dose-painting strategies can be used to increase dose to specific tumor subvolumes. Five-year local, regional, and distant control rates are comparable with patients treated with conventional IMRT. Volume and intensity of dose escalation should be further tailored, given the possible increase in severe acute and chronic toxicity. Adapting treatment and decreasing dose to the swallowing structures might contribute to lower toxicity rates when applied in smaller tumor volumes. Whether adaptive DPBN can significantly improve outcomes is currently being investigated in a novel clinical trial.

Simultaneous integrated boost therapy of carcinoma of the hypopharynx/larynx with and without flattening filter - a treatment planning and dosimetry study

Background

The aim of this study was to investigate if the flattening filter free (FFF) irradiation mode of a linear accelerator (linac) is advantageous as compared to the flat beam (FF) irradiation mode in intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for carcinoma of the hypopharynx / larynx.

Methods

Four treatment plans were created for each of 10 patients for an Elekta Synergy linac with Agility collimating device, a dual arc VMAT and a nine field step and shoot IMRT each with and without flattening filter. Plan quality was compared considering target coverage and dose to the organs at risk. All plans were verified by a 2D–ionization-chamber-array and delivery times were compared. Peripheral point doses were determined as a measure of second cancer risk. The Wilcoxon test was used for statistical analysis with a significance level of 0.05.

Results

Plan quality was similar for all four treatment plans without statistically significant differences of clinical relevance. The clinical goals were met in all plans for the PTV-SIB (V_95% > 95%), the spinal cord (D_1ccm < 45 Gy) and the brain stem (D_1ccm < 48 Gy). For the parotids, the goal of D_50% < 30 Gy was met in 70% and 60% of the plans for the left and right parotid respectively, and the V_95% of the SIB reached an average of 94%. Delivery times were similar for FF and FFF and significantly decreased by around 70% for VMAT as compared to IMRT. Peripheral doses were significantly reduced by 18% in FFF mode as compared to FF and by 26% for VMAT as compared to IMRT. Lowest peripheral doses were found for VMAT FFF, followed by VMAT FF.

Conclusions

The FFF mode of a linear accelerator is advantageous for the treatment of hypopharynx/larynx carcinoma only with respect to reduction of second cancer induction in peripheral organs for the combination of Elekta Synergy linacs and Oncentra® External Beam v4.5 treatment planning system. This might be of interest in a therapy with curative intent.

A Dosimetric Comparison of Dose Escalation with Simultaneous Integrated Boost for Locally Advanced Non-Small-Cell Lung Cancer

Background

Many studies have demonstrated that a higher radiotherapy dose is associated with improved outcomes in non-small-cell lung cancer (NSCLC). We performed a dosimetric planning study to assess the dosimetric feasibility of intensity-modulated radiation therapy (IMRT) with a simultaneous integrated boost (SIB) in locally advanced NSCLC.

Methods

We enrolled twenty patients. Five different dose plans were generated for each patient. All plans were prescribed a dose of 60 Gy to the planning tumor volume (PTV). In the three SIB groups, the prescribed dose was 69 Gy, 75 Gy, and 81 Gy in 30 fractions to the internal gross tumor volume (iGTV).

Results

The SIB-IMRT plans were associated with a significant increase in the iGTV dose (P < 0.05), without increased normal tissue exposure or prolonged overall treatment time. Significant differences were not observed in the dose to the normal lung in terms of the V5 and V20 among the four IMRT plans. The maximum dose (Dmax) in the esophagus moderately increased along with the prescribed dose (P < 0.05).

Conclusions

Our results indicated that escalating the dose by SIB-IMRT is dosimetrically feasible; however, systematic evaluations via clinical trials are still warranted. We have designed a further clinical study (which is registered with ClinicalTrials.gov, number NCT02841228).

Prognostic value of dynamic hypoxia PET in head and neck cancer: Results from a planned interim analysis of a randomized phase II hypoxia-image guided dose escalation trial

BACKGROUND AND PURPOSE

To prospectively assess the prognostic value of tumour hypoxia determined by dynamic [¹⁸F]Fluoromisonidazole (dynFMISO) PET/CT, and to evaluate both feasibility and toxicity in patients with locally advanced squamous cell carcinomas of the head and neck (LASCCHN) treated with dynFMISO image-guided dose escalation (DE) using dose-painting by contours.

PATIENTS AND METHODS

We present a planned interim analysis of a randomized phase II trial. N=25 patients with LASCCHN received baseline dynFMISO PET/CT to derive hypoxic volumes (HV). Patients with tumour hypoxia were randomized into standard radiochemotherapy (stdRT) (70Gy/35 fractions) or DE (77Gy/35 fractions) to the HV. Patients with non-hypoxic tumours were treated with stdRT. Loco-regional control (LRC) in hypoxic patients randomized to stdRT was compared to non-hypoxic patients. Feasibility and toxicity were analysed for patients in the DE arm and compared to stdRT.

RESULTS

With a mean follow-up of 27months, LRC in hypoxic patients receiving stdRT (n=10) was significantly worse compared to the non-hypoxic group (n=5) (2y-LRC 44.4% versus 100%, p=0.048). The respective LRC for the DE group (n=10) was 70.0%. Treatment compliance as well as acute and late toxicity did not show significant differences between the DE and the standard dose arms.

CONCLUSION

Tumour hypoxia determined by baseline dynFMISO PET/CT is associated with a high risk of local failure in patients with LASCCHN. First data suggest that DE to HV is feasible without excess toxicity.

Correlation between fluorodeoxyglucose hotspots on pretreatment positron emission tomography/CT and preferential sites of local relapse after chemoradiotherapy for head and neck squamous cell carcinoma

BACKGROUND

The potential benefits of ¹⁸ F-fluoro-2-deoxy-D-glucose-positron emission tomography/CT (FDG-PET/CT) imaging for radiotherapy (RT) treatment planning of head and neck squamous cell carcinoma (HNSCC) are increasingly being recognized. It has been suggested that intratumoral subvolumes with high FDG avidity ("hotspots") are potential targets for selected dose escalation. The purposes of this study were to demonstrate that pre-RT FDG-PET/CT can identify intratumoral sites at increased risk of local relapse after RT and to determine an optimal threshold to delineate smaller RT target volumes that would facilitate RT dose escalation without impaired tolerance.

METHODS

Seventy-two consecutive patients with locally advanced HNSCC treated by RT ± chemotherapy were included in this study. All patients underwent FDG-PET/CT at initial staging (PET_A ) and during systematic follow-up (PET_R ). FDG-PET/CT was coregistered on the initial CT scan with a rigid method. Various subvolumes (A_X ; × = 30%, 40%, 50%, 60%, 70%, 80%, and 90% standardized uptake value maximum [SUVmax] thresholds) within the primary tumor and in the subsequent local relapse (R_X ; × = 40% and 70% SUVmax thresholds) were compared together (Dice, Jaccard, overlap fraction, common volume/baseline volume, and common volume/recurrent volume).

RESULTS

Nineteen patients (26%) had local relapses. Using a 40% SUVmax threshold, the initial metabolic tumor volume was significantly higher in patients with local relapses than in controlled patients (10.4 ± 8.6 vs 5.1 ± 4.9 cc; p = .002) as well as total lesion glycolysis (117.9 ± 88.6 vs 60.6 ± 80.4; p = .013). For both methods, the overlap index among A₃₀ , A₄₀ , and A₅₀ subvolumes on PET_A and the whole metabolic volume of recurrence R₄₀ and R₇₀ on PET_R showed a moderate agreement (0.52 to 0.43).

CONCLUSION

Our study does not find high overlap index values between the initial tumor and recurrence subvolumes, probably because of a suboptimal coregistration. Our results also confirm that metabolic tumor volume and total lesion glycolysis are independently correlated with recurrence-free survival in patients with HNSCC. Further larger prospective studies with FDG-PET/CT performed in the same RT position and with a validated elastic registration method are needed. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1155-1165, 2017.

Biological dose-escalated definitive radiation therapy in head and neck cancer

OBJECTIVE

To compare treatment outcome of patients with head and neck (HN) tumours treated with definitive radiation therapy that, mainly owing to differences in the fractionation scheme used with simultaneous integrated boost techniques, resulted in a different biological dose.

METHODS

181 patients with HN cancer, prescribed to about 70.2 Gy in the primary tumour, were included in this study. Population cohort was divided into Group <70 and Group ≥70 when the mean dose converted to a 2 Gy fractionation in the primary tumour was less or higher than 70.2 Gy, respectively. The probability of local control (LC), locoregional control (LRC), disease-free survival (DFS) and overall survival (OS) was determined for both groups. The incidence of acute and late complications was compared between the two groups.

RESULTS

At 24 months for Groups <70 and ≥70, LC was 83.2% and 87.5%, LRC was 79.5% and 81.6%, DFS was 56.3% and 66.8% and OS was 63.9% and 71.5% p = ns, respectively. The incidence of acute dysphagia, odynophagia and pain, and late mucositis was significantly higher in Group ≥70 than in Group <70. The rate of xerostomia, dysphonia, radiodermatitis, alopecia, dental complications, hypoacusia and weight loss was comparable between the two groups.

CONCLUSION

The biological dose escalation was safe, but an increase in the incidence of the acute side effects: dysphagia, odynophagia and pain and late mucositis, was obtained. Advances in knowledge: Despite the significant biological dose escalation, within the range of doses delivered to this cohort, no clear dose-response effect was observed.

A comparative analysis between sequential boost and integrated boost intensity-modulated radiation therapy with concurrent chemotherapy for locally-advanced head and neck cancer

BACKGROUND

Planning and delivery of IMRT for locally advanced head and neck cancer (LAHNC) can be performed using sequential boost or simultaneous integrated boost (SIB). Whether these techniques differ in treatment-related outcomes including survival and acute and late toxicities remain largely unexplored.

METHODS

We performed a single institutional retrospective matched cohort analysis on patients with LAHNC treated with definitive chemoradiotherapy to 69.3 Gy in 33 fractions. Treatment was delivered via sequential boost (n = 68) or SIB (n = 141). Contours, plan evaluation, and toxicity assessment were performed by a single experienced physician. Toxicities were graded weekly during treatment and at 3-month follow up intervals. Recurrence-free survival, disease-free survival, and overall survival were estimated via Kaplan-Meier statistical method.

RESULTS

At 4 years, the estimated overall survival was 69.3% in the sequential boost cohort and 76.8% in the SIB cohort (p = 0.13). Disease-free survival was 63 and 69% respectively (p = 0.27). There were no significant differences in local, regional or distant recurrence-free survival. There were no significant differences in weight loss (p = 0.291), gastrostomy tube placement (p = 0.494), or duration of gastrostomy tube dependence (p = 0.465). Rates of acute grade 3 or 4 dysphagia (82% vs 55%) and dermatitis (78% vs 58%) were significantly higher in the SIB group (p < 0.001 and p = 0.012 respectively). Moreover, a greater percentage of the SIB cohort did not receive the prescribed dose due to acute toxicity (7% versus 0, p = 0.028).

CONCLUSIONS

There were no differences in disease related outcomes between the two treatment delivery approaches. A higher rate of grade 3 and 4 radiation dermatitis and dysphagia were observed in the SIB group, however this did not translate into differences in late toxicity. Additional investigation is necessary to further evaluate the acute toxicity differences.

Radiobiological evaluation of simultaneously dose-escalated versus non-escalated intensity-modulated radiation therapy for patients with upper thoracic esophageal cancer

OBJECTIVE

To compare the radiobiological response between simultaneously dose-escalated and non-escalated intensity-modulated radiation therapy (DE-IMRT and NE-IMRT) for patients with upper thoracic esophageal cancer (UTEC) using radiobiological evaluation.

METHODS

Computed tomography simulation data sets for 25 patients pathologically diagnosed with primary UTEC were used in this study. DE-IMRT plan with an escalated dose of 64.8 Gy/28 fractions to the gross tumor volume (GTV) and involved lymph nodes from 25 patients pathologically diagnosed with primary UTEC, was compared to an NE-IMRT plan of 50.4 Gy/28 fractions. Dose-volume metrics, tumor control probability (TCP), and normal tissue complication probability for the lung and spinal cord were compared. In addition, the risk of acute esophageal toxicity (AET) and late esophageal toxicity (LET) were also analyzed.

RESULTS

Compared with NE-IMRT plan, we found the DE-IMRT plan resulted in a 14.6 Gy dose escalation to the GTV. The tumor control was predicted to increase by 31.8%, 39.1%, and 40.9% for three independent TCP models. The predicted incidence of radiation pneumonitis was similar (3.9% versus 3.6%), and the estimated risk of radiation-induced spinal cord injury was extremely low (<0.13%) in both groups. Regarding the esophageal toxicities, the estimated grade ≥2 and grade ≥3 AET predicted by the Kwint model were increased by 2.5% and 3.8%. Grade ≥2 AET predicted using the Wijsman model was increased by 14.9%. The predicted incidence of LET was low (<0.51%) in both groups.

CONCLUSION

Radiobiological evaluation reveals that the DE-IMRT dosing strategy is feasible for patients with UTEC, with significant gains in tumor control and minor or clinically acceptable increases in radiation-induced toxicities.

Comparative treatment planning study on sequential vs. simultaneous integrated boost in head and neck cancer patients: Differences in dose distributions and potential implications for clinical practice

AIM

The purpose of this work was to compare sequential (SeqB) versus simultaneous integrated boost (SIB) radiotherapy plans delivered with volumetric modulated arc therapy (VMAT) for patients with locally advanced squamous cell cancer of the head and neck (HNSCC).

PATIENTS AND METHODS

SeqB and SIB plans using VMAT for 10 HNSCC patients given definitive chemoradiation were generated and analysed for differences in dose distribution, coverage, conformity and homogeneity to the planning target volumes (PTV) 1-3 and sparing of organs at risk (OAR).

RESULTS

The mean delineated volumes ± standard deviations were 137.7 ± 44.8, 351.3 ± 83.9 and 895.6 ± 120.5 cm3 for PTV1-3. The mean volumes encompassed by the corresponding 95 % isodoses were 281 (+ 110 %) ± 73.4, 712.2 (+ 115 %) ± 146.4 and 1381.1 (+ 54 %) ± 217.3 cm3 with SeqB and 138.2 (+ 7 %) ± 40.1, 380.4 (+ 11 %) ± 91.9 and 1057.3 (+ 21 %) ± 161.4 cm3 with SIB for PTV1-3, respectively. Both strategies achieved excellent PTV coverage. SeqB provided significantly better coverage of PTV1 and 3, worse conformity for PTV1-3 and a higher mean dose than prescribed (111-115 %) to PTV2 and 3 (p ≤ 0.007). Both strategies provided satisfactory OAR sparing.

CONCLUSION

This study showed significant dosimetric differences with potential clinical relevance between two VMAT boost strategies regarding coverage, conformity and dose to the PTVs. SIB might cause less toxicity. A clinical phase III/IV trial endorsed by the German Head and Neck Clinical Trials Group (IAG-KHT) will evaluate differences in acute/late toxicity as well as in locoregional recurrences between the two boost techniques.

Unilateral and bilateral neck SIB for head and neck cancer patients : Intensity-modulated proton therapy, tomotherapy, and RapidArc

AIM

To compare simultaneous integrated boost plans for intensity-modulated proton therapy (IMPT), helical tomotherapy (HT), and RapidArc therapy (RA) for patients with head and neck cancer.

PATIENTS AND METHODS

A total of 20 patients with squamous cell carcinoma of the head and neck received definitive chemoradiation with bilateral (n = 14) or unilateral (n = 6) neck irradiation and were planned using IMPT, HT, and RA with 54.4, 60.8, and 70.4 GyE/Gy in 32 fractions. Dose distributions, coverage, conformity, homogeneity to planning target volumes (PTV)s and sparing of organs at risk and normal tissue were compared.

RESULTS

All unilateral and bilateral plans showed excellent PTV coverage and acceptable dose conformity. For unilateral treatment, IMPT delivered substantially lower mean doses to contralateral salivary glands (< 0.001-1.1 Gy) than both rotational techniques did (parotid gland: 6-10 Gy; submandibular gland: 15-20 Gy). Regarding the sparing of classical organs at risk for bilateral treatment, IMPT and HT were similarly excellent and RA was satisfactory.

CONCLUSION

For unilateral neck irradiation, IMPT may minimize the dry mouth risk in this subgroup but showed no advantage over HT for bilateral neck treatment regarding classical organ-at-risk sparing. All methods satisfied modern standards regarding toxicity and excellent target coverage for unilateral and bilateral treatment of head and neck cancer at the planning level.

Preliminary treatment results of proton beam therapy with chemoradiotherapy for stage I-III esophageal cancer

The effect of proton beam therapy (PBT) on various cancers is controversial. We aimed to evaluate the efficacy and safety of PBT with alternating chemoradiotherapy (ACRT) for patients with stage I–III esophageal cancer. Two cycles of systemic chemotherapy with a continuous infusion of 5‐fluorouracil (5‐FU) on days 1–5 and a 5h infusion of nedaplatin (NDP) on day 6 were accompanied by thoracic irradiation using X‐ray therapy and PBT. During the first half of the treatment, X‐rays were delivered to the prophylactic area. During the second half of the treatment, proton beams were used to irradiate the involved field. To reduce the dose of cardiac irradiation, proton beams were delivered with posterior and posterior oblique angles. Between January 2009 and December 2012, 47 patients were enrolled in this study. The median follow‐up duration was 29 months for all patients and 40 months for survivors. The 3 year overall survival rate, progression‐free survival rate, and local control rate were 59.2%, 56.3%, and 69.8%, respectively. With respect to grade 3–4 late toxicities, there were no pleural or pericardial effusions, but two patients (4.3%) had esophageal stenosis, one patient (2.1%) had fistula, and two patients (4.3%) developed radiation pneumonitis. PBT with ACRT might have the potential to reduce the risk of cardiac damage and might become one of the primary methods of esophageal cancer treatment.

Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients

The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT. The mean skin dose and the maximum dose to a contiguous volume of 2cm(3) for head and neck plans and brain plans and a contiguous volume of 5cm(3) for pelvis plans were compared for each treatment technique. Of the 9 patients with head and neck cancer, 3 underwent an integrated boost regimen. One integrated boost plan was replanned with IMRT and VMAT using a traditional boost regimen. For target sites located in the head and neck, VMAT reduced the mean dose and contiguous hot spot most noticeably in the shoulder region by 5.6% and 5.4%, respectively. When using an integrated boost regimen, the contiguous hot spot skin dose in the shoulder was larger on average than a traditional boost pattern by 26.5% and the mean skin dose was larger by 1.7%. VMAT techniques largely decrease the contiguous hot spot in the skin in the pelvis by an average of 36% compared with IMRT. For the same target coverage, VMAT can reduce the skin dose in all the regions of the body, but more noticeably in the shoulders in patients with head and neck and pelvis cancer. We also found that using integrated boost regimens in patients with head and neck cancer leads to higher shoulder skin doses compared with traditional boost regimens.

CBCT image guidance in head and neck irradiation: the impact of daily and weekly imaging protocols

Purpose

This study evaluated the impact of a daily and weekly image-guided radiotherapy protocols in reducing setup errors and setting of appropriate margins in head and neck cancer patients.

Materials and methods

Interfraction and systematic shifts for the hypothetical day 1–3 plus weekly imaging were extrapolated from daily imaging data from 31 patients (964 cone beam computed tomography (CBCT) scans). In addition, residual setup errors were calculated by taking the average shifts in each direction for each patient based on the first three shifts and were presumed to represent systematic setup error. The clinical target volume (CTV) to planning target volume (PTV) margins were calculated using van Herk formula and analysed for each protocol.

Results

The mean interfraction shifts for daily imaging were 0·8, 0·3 and 0·5 mm in the S-I (superior-inferior), L-R (left-right) and A-P (anterior-posterior) direction, respectively. On the other hand the mean shifts for day 1–3 plus weekly imaging were 0·9, 1·8 and 0·5 mm in the S-I, L-R and A-P direction, respectively. The mean day 1–3 residual shifts were 1·5, 2·1 and 0·7 mm in the S-I, L-R and A-P direction, respectively. No significant difference was found in the mean setup error for the daily and hypothetical day 1–3 plus weekly protocol. However, the calculated CTV to PTV margins for the daily interfraction imaging data were 1·6, 3·8 and 1·4 mm in the S-I, L-R and A-P directions, respectively. Hypothetical day 1–3 plus weekly resulted in CTV–PTV margins of 5, 4·2 and 5 mm in the S-I, L-R and A-P direction.

Conclusions

The results of this study show that a daily CBCT protocol reduces setup errors and allows setup margin reduction in head and neck radiotherapy compared to a weekly imaging protocol.

Increase in Tumor Control and Normal Tissue Complication Probabilities in Advanced Head-and-Neck Cancer for Dose-Escalated Intensity-Modulated Photon and Proton Therapy

INTRODUCTION

Presently used radiochemotherapy regimens result in moderate local control rates for patients with advanced head-and-neck squamous cell carcinoma (HNSCC). Dose escalation (DE) may be an option to improve patient outcome, but may also increase the risk of toxicities in healthy tissue. The presented treatment planning study evaluated the feasibility of two DE levels for advanced HNSCC patients, planned with either intensity-modulated photon therapy (IMXT) or proton therapy (IMPT).

MATERIALS AND METHODS

For 45 HNSCC patients, IMXT and IMPT treatment plans were created including DE via a simultaneous integrated boost (SIB) in the high-risk volume, while maintaining standard fractionation with 2 Gy per fraction in the remaining target volume. Two DE levels for the SIB were compared: 2.3 and 2.6 Gy. Treatment plan evaluation included assessment of tumor control probabilities (TCP) and normal tissue complication probabilities (NTCP).

RESULTS

An increase of approximately 10% in TCP was estimated between the DE levels. A pronounced high-dose rim surrounding the SIB volume was identified in IMXT treatment. Compared to IMPT, this extra dose slightly increased the TCP values and to a larger extent the NTCP values. For both modalities, the higher DE level led only to a small increase in NTCP values (mean differences <2%) in all models, except for the risk of aspiration, which increased on average by 8 and 6% with IMXT and IMPT, respectively, but showed a considerable patient dependence.

CONCLUSION

Both DE levels appear applicable to patients with IMXT and IMPT since all calculated NTCP values, except for one, increased only little for the higher DE level. The estimated TCP increase is of relevant magnitude. The higher DE schedule needs to be investigated carefully in the setting of a prospective clinical trial, especially regarding toxicities caused by high local doses that lack a sound dose-response description, e.g., ulcers.