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

Mean Oral Cavity Organ-at-Risk Dose Predicts Opioid Use and Hospitalization during Radiotherapy for Patients with Head and Neck Tumors

BACKGROUND

Approximately 75% of all head and neck cancer patients are treated with radiotherapy (RT). RT to the oral cavity results in acute and late adverse events which can be severe and detrimental to a patient's quality of life and function. The purpose of this study was to explore associations between RT dose to a defined oral cavity organ-at-risk (OAR) avoidance structure, provider- and patient-reported outcomes (PROs), opioid use, and hospitalization.

METHODS

This was a retrospective analysis of prospectively obtained outcomes using multivariable modeling. The study included 196 patients treated with RT involving the oral cavity for a head and neck tumor. A defined oral cavity OAR avoidance structure was used in all patients for RT treatment planning. Validated PROs were collected prospectively. Opioid use and hospitalization were abstracted electronically from medical records.

RESULTS

Multivariable modeling revealed the mean dose to the oral cavity OAR was significantly associated with opioid use (p = 0.0082) and hospitalization (p = 0.0356) during and within 30 days of completing RT.

CONCLUSIONS

The findings of this study may be valuable in RT treatment planning for patients with tumors of the head and neck region to reduce the need for opioid use and hospitalization during treatment.

Proton therapy and oral mucositis in oral & oropharyngeal cancers: outcomes, dosimetric and NTCP benefit

INTRODUCTION

Radiation-induced oral mucositis (RIOM), is a common, debilitating, acute side effect of radiotherapy for oral cavity (OC) and oropharyngeal (OPx) cancers; technical innovations for reducing it are seldom discussed. Intensity-modulated-proton-therapy (IMPT) has been reported extensively for treating OPx cancers, and less frequently for OC cancers. We aim to quantify the reduction in the likelihood of RIOM in treating these 2 subsites with IMPT compared to Helical Tomotherapy.

MATERIAL AND METHODS

We report acute toxicities and early outcomes of 22 consecutive patients with OC and OPx cancers treated with IMPT, and compare the dosimetry and normal tissue complication probability (NTCP) of ≥ grade 3 mucositis for IMPT and HT.

RESULTS

Twenty two patients, 77% males, 41% elderly and 73% OC subsite, were reviewed. With comparable target coverage, IMPT significantly reduced the mean dose and D32, D39, D45, and D50, for both the oral mucosa (OM) and spared oral mucosa (sOM). With IMPT, there was a 7% absolute and 16.5% relative reduction in NTCP for grade 3 mucositis for OM, compared to HT. IMPT further reduced NTCP for sOM, and the benefit was maintained in OC, OPx subsites and elderly subgroup. Acute toxicities, grade III dermatitis and mucositis, were noted in 50% and 45.5% patients, respectively, while 22.7% patients had grade 3 dysphagia. Compared with published data, the hospital admission rate, median weight loss, feeding tube insertion, unplanned treatment gaps were lower with IMPT. At a median follow-up of 15 months, 81.8% were alive; 72.7%, alive without disease and 9%, alive with disease.

CONCLUSION

The dosimetric benefit of IMPT translates into NTCP reduction for grade 3 mucositis compared to Helical Tomotherapy for OPx and OC cancers and encourages the use of IMPT in their management.

Correlation of oral mucosa dose and volume parameters with Grade 3 mucositis, in patients treated with volumetric modulated arc radiotherapy for oropharyngeal cancer?

Background

Oral mucositis is the dose-limiting toxicity of chemoradiation in oropharyngeal cancer patients, which can be minimized by giving constraints to oral mucosa. However, the constraints defined in literature are extrapolated from chemoradiation in head and neck cancers as a whole. This study aims to determine oral mucosa dose-volume parameters that can predict grade ≥ 3 acute oral mucositis in oropharyngeal cancer patients treated with volumetric modulated arc radiotherapy.

Methods

This prospective study was done in 52 patients of locally advanced oropharyngeal cancer treated with Volumetric modulated arc radiotherapy. Dose-volume histogram data were extracted and then acute oral mucosa toxicity was analysed. Receiver operating characteristic analysis and logistic regression were carried out to determine predictive factors for grade ≥ 3 mucositis.

Results

Grade ≥ 3 acute oral mucositis occurred in 57.6% (30/52) patients in the study. V30Gy > 53.35% (P = 0.005) was an independent dosimetric factor related to grade ≥ 3 acute toxicity. In the receiver operating characteristic curve, the area under V30Gy was 0.770 (P = 0.001); the cut-off value of V30 was 46.23% (sensitivity, 0.80; specificity, 0.91).

Conclusions

Dose-volume histogram analysis predicts V30 > 53.35% as independent factors for grade ≥ 3 acute oral mucositis in patients with oropharyngeal cancers treated with Volumetric modulated arc radiotherapy. Studies in future with more patient number can further validate the above results.

Magnetic Resonance Imaging-Based Delineation of Organs at Risk in the Head and Neck Region

Purpose

The aim of this article is to establish a comprehensive contouring guideline for treatment planning using only magnetic resonance images through an up-to-date set of organs at risk (OARs), recommended organ boundaries, and relevant suggestions for the magnetic resonance imaging (MRI)-based delineation of OARs in the head and neck (H&N) region.

Methods and Materials

After a detailed review of the literature, MRI data were collected from the H&N region of healthy volunteers. OARs were delineated in the axial, coronal, and sagittal planes on T2-weighted sequences. Every contour defined was revised by 4 radiation oncologists and subsequently by 2 independent senior experts (H&N radiation oncologist and radiologist). After revision, the final structures were presented to the consortium partners.

Results

A definitive consensus was reached after multi-institutional review. On that basis, we provided a detailed anatomic and functional description and specific MRI characteristics of the OARs.

Conclusions

In the era of precision radiation therapy, the need for well-built, straightforward contouring guidelines is on the rise. Precise, uniform, delineation-based, automated OAR segmentation on MRI may lead to increased accuracy in terms of organ boundaries and analysis of dose-dependent sequelae for an adequate definition of normal tissue complication probability.

Delineation of Oral Mucosa as a Pseudo-Organ-at-Risk May Lead to a Decrease in the Incidence of Oral Mucositis: A Dosimetric Analysis of Intensity-Modulated Radiation Therapy Plans in Head and Neck Cancers

Introduction

Oral mucositis is a common and potentially serious complication of radiation in head and neck cancer treatment. Severe mucositis causes pain, difficulty in chewing and swallowing that can cause treatment breaks and can cause treatment failures leading to local recurrence or a decrease in overall survival. The contouring of the planning target volume (PTV) and organ at risk (OAR) leaves some undefined regions on computed tomography imaging. The treatment planning system uses these regions as dumping sites for the dose in order to achieve the optimum plan. The present study was done to assess the dose going to these unspecified regions termed as pseudo-OARs and whether delineation of these structures and prescribing a dose constraint will reduce the dose to the oral mucosa without compromising the quality of the treatment plan.

Methods

Twenty patients of head and neck cancer were selected and were randomly placed in two arms. One was intensity-modulated radiation therapy (IMRT) arm I, which included the initial plans with which the patients were treated where the pseudo-OAR was not delineated and hence was not considered in the planning process. After giving treatment, the pseudo-OAR was delineated to see the dose dumped into the area outside the PTV. The other was IMRT arm II, where another virtual plan of the same patients of arm I was made wherein the delineation of the pseudo-OAR was done before planning and dose constraint prescribed. The pseudo-OAR consisted of anterior oral mucosa, part of mandible and maxilla, which was adjacent to the PTV in oropharynx and contralateral buccal mucosa patients. The dose constraint given to the pseudo-OAR was Dmean ≤30 Gy. Statistical significance was calculated by using a paired t-test. A p-value of <0.05 was considered as statistically significant.

Results

The dosimetric parameters of PTV were comparable in both the IMRT arms. The pre-specified objective was fulfilled with both the study arms. The dose homogeneity and conformity was also similar. The dosimetric parameters of other OARs were within the prescribed dose constraints. The Dmean value of the pseudo-OAR in arm I was 31.28 Gy ± 3.55 Gy and 7.87 Gy ± 9.11 Gy in arm II and the p-value was significant (p=0.001), whereas the Dmax in arm I was 61.82 Gy ± 5.91 Gy and 61.23 Gy ± 5.54 Gy in arm II (p=0.6). The dose to the pseudo-OAR in IMRT arm II was reduced drastically by 75%, which was statistically significant.

Conclusion

The delineation of oral mucosa as a pseudo-OAR should routinely be done. The dose constraints need to be optimized by clinical studies, which might probably decrease the incidence and severity of oral mucositis.

A Dosimetric Comparison of Oral Cavity Sparing in the Unilateral Treatment of Early Stage Tonsil Cancer: IMRT, IMPT, and Tongue-Deviating Oral Stents

Introduction

Tongue-deviating oral stents (TDOS) are commonly used during unilateral neck radiation therapy to reduce unnecessary dose to nontarget oral structures. Their benefit in the setting of highly conformal treatment techniques, however, is not defined. The goal of this study was to investigate the potential benefit of TDOS use on dosimetric parameters in unilateral intensity modulated radiation therapy (IMRT) and intensity modulated proton therapy (IMPT).

Methods

A total of 16 patients with T1-2 tonsil cancer treated at a single institution were selected, of which 8 were simulated/treated with a TDOS and 8 without a TDOS. All received definitive unilateral IMRT to a dose of 66 Gy in 30 fx. IMPT plans were generated for each patient for study purposes and optimized according to standard institutional practice.

Results

For IMRT plans, the presence of a TDOS (vs without) was associated with a significantly lower oral mucosa mean dose (31.4 vs 35.3 Gy; P = .020) and V30 (42.7% vs 57.1%; P = .025). For IMPT plans, the presence of TDOS (vs without) was not associated with any improvement in oral mucosa mean dose (18.3 vs 19.9 Gy; P = .274) or V30 (25.0% vs 26.2%; P = .655). IMPT plans without TDOS compared with IMRT plans with TDOS demonstrated reduced oral mucosa mean dose (P < .001) and V30 (P < .001).

Conclusion

The use of a TDOS for the unilateral treatment of well-lateralized tonsil cancers was associated with oral mucosa sparing for IMRT, but not for IMPT. Moreover, mucosa sparing was improved for IMPT plans without a TDOS compared to IMRT plans with a TDOS.

Three photobiomodulation protocols in the prevention/treatment of radiotherapy-induced oral mucositis

PURPOSE

To compare three Photobiomodulation protocols to prevent/treat oral mucositis associated to radiotherapy.

METHODS

Seventy-three patients with cancer in oral cavity, oropharynx, and nasopharynx, who underwent RT with dose in facial fields equal or higher than 6000 cGy were randomized into three groups (mean RT dose = 66 cGy ±4.9). Protocols of Group 1 was 660 nm, 15 mW, 3.8 J/cm2, Group 2 660 nm, 25 mW, 6.3 J/cm2 both starting on the first day of radiotherapy, and group 3 660 nm, 15 mW, 3.8 J/cm2 for therapeutic purpose. The patients of group 1 and 2 were irradiated at 40 points daily covering non-keratinizing oral mucosa. The spot size (probe's tip surface size) was 0.040 cm2 for all groups. Oral mucositis was evaluated according to both WHO and NCI scales, and pain related to oral mucositis was scored using the VAS.

RESULTS

Patients from group 1 presented with grade II oral mucositis later than groups 2 and 3 (p < 0.001). Moreover, groups 2 and 3 also presented with a mean higher of oral mucositis grade than group 1, p < 0.001. Pain scores were lower in group 1 (p = 0.002).

CONCLUSIONS

The Photobiomodulation used in Group 1 was more effective than the protocols used in groups 2 and 3 in controlling the grade II oral mucositis intensity, and mean pain scores.

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.

Radiomics and Machine Learning for Radiotherapy in Head and Neck Cancers

Introduction: An increasing number of parameters can be considered when making decisions in oncology. Tumor characteristics can also be extracted from imaging through the use of radiomics and add to this wealth of clinical data. Machine learning can encompass these parameters and thus enhance clinical decision as well as radiotherapy workflow. Methods: We performed a description of machine learning applications at each step of treatment by radiotherapy in head and neck cancers. We then performed a systematic review on radiomics and machine learning outcome prediction models in head and neck cancers. Results: Machine Learning has several promising applications in treatment planning with automatic organ at risk delineation improvements and adaptative radiotherapy workflow automation. It may also provide new approaches for Normal Tissue Complication Probability models. Radiomics may provide additional data on tumors for improved machine learning powered predictive models, not only on survival, but also on risk of distant metastasis, in field recurrence, HPV status and extra nodal spread. However, most studies provide preliminary data requiring further validation. Conclusion: Promising perspectives arise from machine learning applications and radiomics based models, yet further data are necessary for their implementation in daily care.

Assessing Novel Drugs and Radiation Technology in the Chemoradiation of Oropharyngeal Cancer

Integrating immunotherapy, proton therapy and biological dose escalation into the definitive chemoradiation of oropharyngeal cancer poses several challenges. Reliable and reproducible data must be obtained in a timely fashion. However, despite recent international radiotherapy contouring guidelines, controversy persists as to the applicability of such guidelines to all cases. Similarly, a lack of consensus exists concerning both the definition of the organ at risk for oral mucositis and the most appropriate endpoint to measure for this critical toxicity. Finally, the correlation between early markers of efficacy such as complete response on PET CT following treatment and subsequent survival needs elucidation for biological subsets of oropharyngeal cancer.

Pharmacological modulation of radiation-induced oral mucosal complications

Radiation-induced mucositis is a common toxicity, especially in patients with head and neck cancers. Despite recent technological advances in radiation therapy, such as intensity-modulated radiotherapy, radiation-induced mucositis is still causing treatment disruptions, negatively affecting patients' long and short term quality of life, and impacting medical resources use with economic consequences. The objective of this article was to review the latest updates in the management of radiation-induced mucositis, with a focus on pharmaceutical strategies for the prevention or treatment of mucositis. Although numerous studies analysing the prevention and management of oral radiation-induced mucositis have been conducted, there are still few reliable data to guide daily clinical practice. Furthermore, most of the tested drugs have shown no (anti-inflammatory cytokine, growth factors) or limited (palifermin) effect. Therapies for acute oral mucositis are predominantly focused on improving oral hygiene and providing symptoms control. Although low-level laser therapy proved efficient in preventing radiation-induced oral mucositis in patients with head and neck cancer, this intervention requires equipment and trained medical staff, and is therefore insufficiently developed in clinical routine. New effective pharmacological agents able to prevent or reverse radio-induced mucositis are required.

Oral Mucosa Dose Parameters Predicting Grade ≥3 Acute Toxicity in Locally Advanced Nasopharyngeal Carcinoma Patients Treated With Concurrent Intensity-Modulated Radiation Therapy and Chemotherapy: An Independent Validation Study Comparing Oral Cavity versus Mucosal Surface Contouring Techniques

PURPOSE: To determine whether volumes based on the contours of the mucosal surface instead of the oral cavity can be used to predict grade ≥3 acute oral mucosa toxicity in patients with locally advanced nasopharyngeal carcinoma (LANPC) treated with concurrent intensity-modulated radiation therapy (IMRT) and chemotherapy. METHODS AND MATERIALS: A standardized method for the oral cavity (oral cavity contours, OCC) and a novel method for the mucosal surface (mucosal surface contours, MSC) were developed for the oral mucosa and prospectively applied to the radiation treatment plans of 92 patients treated with concurrent IMRT and chemotherapy for LANPC. Dose–volume histogram (DVH) data were extracted and then toxicity was analyzed. Receiver operating characteristic analysis and logistic regression were carried out for both contouring methods. RESULTS: Grade ≥3 acute oral mucosa toxicity occurred to 20.7% (19/92) of patients in the study. A highly significant dose–volume relationship between oral mucosa irradiation and acute oral mucosa toxicity was supported by using both oral cavity and mucosal surface contouring techniques. In logistic regression, body weight loss was an independent factor related to grade ≥3 acute toxicity for OCC and MSC (P = .017 and 0.005, respectively), and the independent factor of dosimetric parameters for OCC and MSC were V30Gy (P = .003) and V50Gy (P = .003) respectively. In the receiver operating characteristics curve, the areas under V30Gy of the OCC curves was 0.753 (P = .001), while the areas under V50Gy of MSC curves was 0.714 (P = .004); the cut-off value was 73.155% (sensitivity, 0.842; specificity, 0.671) and 14.32% (sensitivity, 0.842; specificity, 0.575), respectively. CONCLUSION: DVH analysis of mucosal surface volumes accurately predicts grade ≥3 acute oral mucosa toxicity in patients with LANPC receiving concurrent IMRT and chemotherapy, but in clinical practice the MSC method appears no better than the OCC one.

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.

A randomised controlled trial of Caphosol mouthwash in management of radiation-induced mucositis in head and neck cancer

PURPOSE

This phase III, non-blinded, parallel-group, randomised controlled study evaluated the efficacy of Caphosol mouthwash in the management of radiation-induced oral mucositis (OM) in patients with head and neck cancer (HNC) undergoing radical (chemo)radiotherapy.

PATIENTS AND METHODS

Eligible patients were randomised at 1:1 to Caphosol plus standard oral care (intervention) or standard oral care alone (control), stratified by radiotherapy technique and use of concomitant chemotherapy. Patients in the intervention arm used Caphosol for 7weeks: 6weeks during and 1-week post-radiotherapy. The primary endpoint was the incidence of severe OM (CTCAE ⩾grade 3) during and up to week 8 post-radiotherapy. Secondary endpoints include pharyngeal mucositis, dysphagia, pain and quality of life.

RESULTS

The intervention (n=108) and control (n=107) arms were well balanced in terms of patient demographics and treatment characteristics. Following exclusion of patients with missing data, 210 patients were available for analysis. The incidence of severe OM did not differ between the intervention and control arms (64.1% versus 65.4%, p=0.839). Similarly, no significant benefit was observed for other secondary endpoints. Overall, compliance with the recommended frequency of Caphosol was low.

CONCLUSION

Caphosol did not reduce the incidence or duration of severe OM during and after radiotherapy in HNC.

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.

A controlled study of use of patient-reported outcomes to improve assessment of late effects after treatment for head-and-neck cancer

BACKGROUND AND PURPOSE

To test the effect of longitudinal feedback on late effects reported by survivors of head-and-neck cancer (HNC) to clinicians during regular follow-up.

MATERIAL AND METHODS

A total of 266 participants were sequentially assigned to either control or intervention group and filled in electronic versions of the EORTC QLQ C-30, H&N35, HADS and a study-specific list of symptoms at up to two consecutive follow-up visits. Participants' symptoms displayed according to severity were provided to the clinician for the intervention group but not for the control group. Linear mixed-effects models were used to examine the number of symptoms assessed by clinicians (primary outcome). Multivariate linear regression models examined participants' long-term symptom control and QoL (secondary outcome).

RESULTS

More symptoms were assessed by clinicians in the intervention group at all three visits (P<0.001, <0.001, and P=0.04). No effect was observed on most patient outcomes. When prompted by patient-reported outcomes at consultations, clinicians and patients were in better agreement about the occurrence of severe symptoms at all three visits.

CONCLUSION

Timely patient-reported outcomes to clinicians in routine follow-up of HNC survivors enhanced clinicians' rates of assessment of late symptoms. Giving reports of patient-reported outcome to clinicians had limited impact on participants' QoL or symptom burden.

WITHDRAWN: Does Dose to an Oral Mucosa Organ at Risk Predict the Duration of Grade 3 Mucositis after Intensity-modulated Radiotherapy for Oropharyngeal Cancer?

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Assessment of fully-automated atlas-based segmentation of novel oral mucosal surface organ-at-risk

BACKGROUND AND PURPOSE

Current oral mucositis normal tissue complication probability models, based on the dose distribution to the oral cavity volume, have suboptimal predictive power. Improving the delineation of the oral mucosa is likely to improve these models, but is resource intensive. We developed and evaluated fully-automated atlas-based segmentation (ABS) of a novel delineation technique for the oral mucosal surfaces.

MATERIAL AND METHODS

An atlas of mucosal surface contours (MSC) consisting of 46 patients was developed. It was applied to an independent test cohort of 10 patients for whom manual segmentation of MSC structures, by three different clinicians, and conventional outlining of oral cavity contours (OCC), by an additional clinician, were also performed. Geometric comparisons were made using the dice similarity coefficient (DSC), validation index (VI) and Hausdorff distance (HD). Dosimetric comparisons were carried out using dose-volume histograms.

RESULTS

The median difference, in the DSC and HD, between automated-manual comparisons and manual-manual comparisons were small and non-significant (-0.024; p=0.33 and -0.5; p=0.88, respectively). The median VI was 0.086. The maximum normalised volume difference between automated and manual MSC structures across all of the dose levels, averaged over the test cohort, was 8%. This difference reached approximately 28% when comparing automated MSC and OCC structures.

CONCLUSIONS

Fully-automated ABS of MSC is suitable for use in radiotherapy dose-response modelling.

Evaluation of the Risk of Grade 3 Oral and Pharyngeal Dysphagia Using Atlas-Based Method and Multivariate Analyses of Individual Patient Dose Distributions

PURPOSE

The study aimed to apply the atlas of complication incidence (ACI) method to patients receiving radical treatment for head and neck squamous cell carcinomas (HNSCC), to generate constraints based on dose-volume histograms (DVHs), and to identify clinical and dosimetric parameters that predict the risk of grade 3 oral mucositis (g3OM) and pharyngeal dysphagia (g3PD).

METHODS AND MATERIALS

Oral and pharyngeal mucosal DVHs were generated for 253 patients who received radiation (RT) or chemoradiation (CRT). They were used to produce ACI for g3OM and g3PD. Multivariate analysis (MVA) of the effect of dosimetry, clinical, and patient-related variables was performed using logistic regression and bootstrapping. Receiver operating curve (ROC) analysis was also performed, and the Youden index was used to find volume constraints that discriminated between volumes that predicted for toxicity.

RESULTS

We derived statistically significant dose-volume constraints for g3OM over the range v28 to v70. Only 3 statistically significant constraints were derived for g3PD v67, v68, and v69. On MVA, mean dose to the oral mucosa predicted for g3OM and concomitant chemotherapy and mean dose to the inferior constrictor (IC) predicted for g3PD.

CONCLUSIONS

We have used the ACI method to evaluate incidences of g3OM and g3PD and ROC analysis to generate constraints to predict g3OM and g3PD derived from entire individual patient DVHs. On MVA, the strongest predictors were radiation dose (for g3OM) and concomitant chemotherapy (for g3PD).