Characteristics of response of oral and pharyngeal mucosa in patients receiving chemo-IMRT for head and neck cancer using hypofractionated accelerated radiotherapy

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.

Intensity modulated radiation therapy and oral mucosa sparing in Head and neck cancer patients: A systematic review on behalf of Italian Association of Radiation Oncology - Head and neck working group

Oral mucositis is a common dose-limiting toxicity during radiotherapy with or without chemotherapy in head and neck cancer patients. This potentially severe complication globally worsens quality of life and negatively impacts local control and survival's outcomes. Several studies have been published on feasibility and/or clinical benefit of intensity modulated radiotherapy (IMRT) mucosa-sparing technique. In 2017, the Italian Association of Radiation Oncology Head and Neck Cancer Working Group organized a study group to perform a systematic review. The aim was to verify if practical indications, including dose-constraints and demonstrated clinical benefit, could be proposed for oral mucosa (OM)-sparing IMRT in order to reduce the incidence of severe acute mucositis. Although dose to OM should be reduced as much as possible without compromising target volumes coverage, it is still tricky to firmly state that OM-sparing procedure should be considered the standard of care, especially due to high subjective variability in OM contour.

Systematic review and meta-analysis of the impact of dosimetry to dysphagia and aspiration related structures

BACKGROUND

Technological advances in radiotherapy have allowed investigations into new methods to spare healthy tissue in those treated for head and neck cancer. This systematic review with meta-analysis demonstrates the effect that radiation has on swallowing.

METHODS

Selection and analysis of studies examining the effect of radiation to swallowing structures. A fixed effects meta-analysis calculated the pooled proportions for select outcomes of dysphagia, common across many studies.

RESULTS

The majority of the papers found a correlation between radiation dose to the swallowing structures and dysphagia, however a meta-analysis found the studies carried a significant degree of heterogeneity. The appraisal demonstrates the need for large-scale studies using a randomized design and instrumental dysphagia assessments.

CONCLUSIONS

Radiation dose to dysphagia and aspiration structures is correlated with incidence of dysphagia and aspiration. The variables in this population contribute to the heterogeneity within and cross studies and future studies should consider controlling for this.

Normal Tissue Complication Probability (NTCP) Modelling of Severe Acute Mucositis using a Novel Oral Mucosal Surface Organ at Risk

AIMS

A normal tissue complication probability (NTCP) model of severe acute mucositis would be highly useful to guide clinical decision making and inform radiotherapy planning. We aimed to improve upon our previous model by using a novel oral mucosal surface organ at risk (OAR) in place of an oral cavity OAR.

MATERIALS AND METHODS

Predictive models of severe acute mucositis were generated using radiotherapy dose to the oral cavity OAR or mucosal surface OAR and clinical data. Penalised logistic regression and random forest classification (RFC) models were generated for both OARs and compared. Internal validation was carried out with 100-iteration stratified shuffle split cross-validation, using multiple metrics to assess different aspects of model performance. Associations between treatment covariates and severe mucositis were explored using RFC feature importance.

RESULTS

Penalised logistic regression and RFC models using the oral cavity OAR performed at least as well as the models using mucosal surface OAR. Associations between dose metrics and severe mucositis were similar between the mucosal surface and oral cavity models. The volumes of oral cavity or mucosal surface receiving intermediate and high doses were most strongly associated with severe mucositis.

CONCLUSIONS

The simpler oral cavity OAR should be preferred over the mucosal surface OAR for NTCP modelling of severe mucositis. We recommend minimising the volume of mucosa receiving intermediate and high doses, where possible.

Evaluation of radiotherapy techniques for radical treatment of lateralised oropharyngeal cancers : Dosimetry and NTCP

AIM

The aim of this study was to investigate potential advantages and disadvantages of three-dimensional conformal radiotherapy (3DCRT), multiple fixed-field intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in terms of dose to the planning target volume (PTV), organs at risk (OARs) and normal tissue complication probability (NTCP) for delivering ipsilateral radiotherapy.

MATERIALS AND METHODS

3DCRT, IMRT and VMAT were compared in patients with well-lateralised primary tonsillar cancers who underwent primary radical ipsilateral radiotherapy. The following parameters were compared: conformity index (CI); homogeneity index (HI); dose-volume histograms (DVHs) of PTVs and OARs; NTCP, risk of radiation-induced cancer and dose accumulation during treatment.

RESULTS

IMRT and VMAT were superior to 3DCRT in terms of CI, HI and dose to the target volumes, as well as mandible and dose accumulation robustness. The techniques were equivalent in terms of dose and NTCP for the contralateral oral cavity, contralateral submandibular gland and mandible, when specific dose constraint objectives were used on the oral cavity volume. Although the volume of normal tissue exposed to low-dose radiation was significantly higher with IMRT and VMAT, the risk of radiation-induced secondary malignancy was dependant on the mathematical model used.

CONCLUSION

This study demonstrates the superiority of IMRT/VMAT techniques over 3DCRT in terms of dose homogeneity, conformity and consistent dose delivery to the PTV throughout the course of treatment in patients with lateralised oropharyngeal cancers. Dosimetry and NTCP calculations show that these techniques are equivalent to 3DCRT with regard to the risk of acute mucositis when specific dose constraint objectives were used on the contralateral oral cavity OAR.

Normal tissue complication probability (NTCP) modelling using spatial dose metrics and machine learning methods for severe acute oral mucositis resulting from head and neck radiotherapy

BACKGROUND AND PURPOSE

Severe acute mucositis commonly results from head and neck (chemo)radiotherapy. A predictive model of mucositis could guide clinical decision-making and inform treatment planning. We aimed to generate such a model using spatial dose metrics and machine learning.

MATERIALS AND METHODS

Predictive models of severe acute mucositis were generated using radiotherapy dose (dose-volume and spatial dose metrics) and clinical data. Penalised logistic regression, support vector classification and random forest classification (RFC) models were generated and compared. Internal validation was performed (with 100-iteration cross-validation), using multiple metrics, including area under the receiver operating characteristic curve (AUC) and calibration slope, to assess performance. Associations between covariates and severe mucositis were explored using the models.

RESULTS

The dose-volume-based models (standard) performed equally to those incorporating spatial information. Discrimination was similar between models, but the RFCstandard had the best calibration. The mean AUC and calibration slope for this model were 0.71 (s.d.=0.09) and 3.9 (s.d.=2.2), respectively. The volumes of oral cavity receiving intermediate and high doses were associated with severe mucositis.

CONCLUSIONS

The RFCstandard model performance is modest-to-good, but should be improved, and requires external validation. Reducing the volumes of oral cavity receiving intermediate and high doses may reduce mucositis incidence.

Influence of dosimetric and clinical criteria on the requirement of artificial nutrition during radiotherapy of head and neck cancer patients

PURPOSE/OBJECTIVE(S)

Intensification of radiotherapy and chemotherapy for head-and-neck cancer (HNC) may lead to increased rates of long term dysphagia as a severe side effect. Mucositis and consequent swallowing problems require artificial nutrition in many HNC patients undergoing radiotherapy or chemoradiation. It is unknown, which predict factors for prophylactic PEG tube insertion appear useful.

MATERIALS/METHODS

From an institutional database, 101 patients (72 male, 29 female, mean age 59.5years) were identified who underwent radiotherapy or chemoradiation for HNC. Primary end point of the investigation was the need for artificial nutrition for more than 4days during radiotherapy. Dose volume parameters of defined normal tissue structures potentially of relevance for swallowing ability as well as clinical factors were used to develop a predictive model using a binary multiple logistic regression model.

RESULTS

Whereas several dosimetric and clinical factors were significant predictors for the need of artificial nutrition on univariate analysis, on multivariate analysis only three factors remained independently significant: mean dose to the oropharynx+1cm circumferential margin, ECOG performance state (0-1 vs. 2-4), and the use of chemotherapy (yes vs. no).

CONCLUSIONS

Using a 3 parameter model we could distinguish HNC-patients with different risks for the need of artificial nutrition during radiotherapy. After independent validation, the model could be helpful to decision on prophylactic PEG tube insertion.

Predictors of mucositis in oropharyngeal and oral cavity cancer in patients treated with volumetric modulated radiation treatment: A dose-volume analysis

BACKGROUND

The purpose of this study was to assess predictors of mucositis in oropharyngeal and oral cavity cancer after definitive or adjuvant volumetric modulated arc radiotherapy (VMAT) +/- chemotherapy.

METHODS

Fifty patients were evaluated. Statistical analysis was performed for the following parameters as potential predictors of mucositis ≥ G2: total oral mucosa and oral mucosa minus target high-low radiation dose regions (planning target volumes [PTVs]), mean dose (Dmean ), maximum dose (Dmax ), chemotherapy, weight loss, and dysphagia.

RESULTS

Mucositis ≥ G2 was found to be statistically related to chemotherapy, weight loss, dysphagia ≥ G2, total oral mucosa Dmean ≥50 Gy and Dmax ≥65 Gy, V45 Gy >40%, V50 Gy >30%, and V55 Gy >20% of the oral mucosa minus target PTVs. A ratio between total oral mucosa and oral mucosa minus target PTVs >2.5 is related to G3 mucositis (p = .03).

CONCLUSION

New parameters were found as predictors of moderate-severe mucositis. © 2015 Wiley Periodicals, Inc. Head Neck 38: E815-E819, 2016.

A novel method for delineation of oral mucosa for radiotherapy dose-response studies

There is currently no standard method for delineating the oral mucosa and most attempts are oversimplified. A new method to obtain anatomically accurate contours of the oral mucosa surfaces was developed and applied to 11 patients. This is expected to represent an opportunity for improved toxicity modelling of oral mucositis.

Helical tomotherapy: an innovative radiotherapy technique for the treatment of locally advanced oropharynx and inoperable oral cavity carcinoma

BACKGROUND

To report our initial clinical experience of helical tomotherapy (HT) in the treatment of locally advanced oropharynx and inoperable oral cavity cancer.

METHODS

Between February 2008 and January 2011, 24 consecutive patients, 15 with oropharyngeal cancer and 9 with oral cavity cancer were treated with exclusive radiotherapy or concomitant chemoradiotherapy. Simultaneous integrated boost (SIB) in 30 fractions scheme was prescribed to all patients, using Helical Tomotherapy. Doses administered to primary tumor, oropharynx/oral cavity and positive lymph-nodes and negative lymph-nodes were 66-67.5 Gy, 60-63 Gy and 54 Gy, respectively.

RESULTS

Complete response rate for the oropharynx and the oral cavity group was 86.7% and 77.8%, respectively. The 1 and 2-year Overall Survival (OS) and Disease Free Survival (DFS) rate for the oropharynx group was 92.9%, 85.1%, 92.9% and 77.4% respectively. For the oral cavity group, 1 and 2-year OS and DFS rates were 55.6%, 55.6%, 75% and 75%, respectively. No patient developed grade ≥3 mucositis, dysphagia or dermatitis. The maximum late-toxicity grade observed was 2, for all the variables examined.

CONCLUSIONS

HT appears to achieve encouraging clinical outcomes in terms of response, survival and toxicity rates.

Dose-response analysis of acute oral mucositis and pharyngeal dysphagia in patients receiving induction chemotherapy followed by concomitant chemo-IMRT for head and neck cancer

Dose-response curves (DRCs) and the quantitative parameters describing these curves were generated for grade 3 oral mucositis and dysphagia in 144 patients using individual patient DVHs. Curve fits to the oral mucositis clinical data yielded parameter values of mean dose in 2 Gy equivalent, MD(50) = 51 Gy (95% CI 40-61), slope of the curve, k = 1(95% CI 0.6-1.5). R(2) value for the goodness of fit was 0.80. Fits to the grade 3 dysphagia clinical data yielded parameter values of MD(50) = 44.5 Gy (95% CI 36-53), k = 2.6 (95% CI 0.8-4.5). R(2) value for the goodness of fit was 0.65. This is the first study to derive DRCs in patients receiving induction chemotherapy followed by chemo-radiation (IC-C-IMRT) for head and neck cancer. The dose-response model described in this study could be useful for comparing acute mucositis rates for different dose-fractionation schedules when using IMRT for head and neck cancer.

Predictive modelling for swallowing dysfunction after primary (chemo)radiation: results of a prospective observational study

BACKGROUND AND PURPOSE

The purpose of this large multicentre prospective cohort study was to identify which dose volume histogram parameters and pre-treatment factors are most important to predict physician-rated and patient-rated radiation-induced swallowing dysfunction (RISD) in order to develop predictive models for RISD after curative (chemo) radiotherapy ((CH) RT).

MATERIAL AND METHODS

The study population consisted of 354 consecutive head and neck cancer patients treated with (CH) RT. The primary endpoint was grade 2 or more swallowing dysfunction according to the RTOG/EORTC late radiation morbidity scoring criteria at 6 months after (CH) RT. The secondary endpoints were patient-rated swallowing complaints as assessed with the EORTC QLQ-H&N35 questionnaire. To select the most predictive variables a multivariate logistic regression analysis with bootstrapping was used.

RESULTS

At 6 months after (CH) RT the bootstrapping procedure revealed that a model based on the mean dose to the superior pharyngeal constrictor muscle (PCM) and mean dose to the supraglottic larynx was most predictive. For the secondary endpoints different predictive models were found: for problems with swallowing liquids the most predictive factors were the mean dose to the supraglottic larynx and radiation technique (3D-CRT versus IMRT). For problems with swallowing soft food the mean dose to the middle PCM, age (18-65 versus >65 years), tumour site (naso/oropharynx versus other sites) and radiation technique (3D-CRT versus IMRT) were the most predictive factors. For problems with swallowing solid food the most predictive factors were the mean dose to the superior PCM, the mean dose to the supraglottic larynx and age (18-65 versus >65 years). And for choking when swallowing the V60 of the oesophageal inlet muscle and the mean dose to the supraglottic larynx were the most predictive factors.

CONCLUSIONS

Physician-rated and patient-rated RISD in head and neck cancer patients treated with (CH) RT cannot be predicted with univariate relationships between the dose distribution in a single organ at risk and an endpoint. Separate predictive models are needed for different endpoints and factors other than dose volume histogram parameters are important as well.