Risk Of Xerostomia Research Articles

Prevalence of xerostomia in an adolescent inpatient psychiatric clinic: a preliminary study.

Adolescents with psychiatric conditions may be at risk for xerostomia. In this preliminary study, we estimated xerostomia prevalence in adolescents ages 9 to 17 years from an inpatient psychiatric clinic (N = 25) and examined whether: (1) gender and age were associated with xerostomia and (2) xerostomia was associated with self-reported cavities. We used a modified 11-item Xerostomia Index to identify xerostomia (no/yes) and asked if adolescents ever had or currently have cavities (no/yes). The mean age was 14 years (SD = 2.3) and 72% were male. Sixty percent reported xerostomia (SD = 50). There were no significant associations between xerostomia and gender (p = 0.99) or age (p = 0.66), or between xerostomia and past (p = 0.26) or current cavities (p = 0.11). Larger proportions of adolescents with xerostomia reported previous and current cavities. Sixty percent of adolescents from an inpatient psychiatric clinic reported having xerostomia, which may lead to increased caries risk over time. Additional research should examine the prevalence and consequences of xerostomia in high-risk adolescents.

A risk prediction model for xerostomia: a retrospective cohort study

We investigated the prevalence of xerostomia in dental patients and built a xerostomia risk prediction model by incorporating a wide range of risk factors. Socio-demographic data, past medical history, self-reported dry mouth and related symptoms were collected retrospectively from January 2010 to September 2013 for all new dental patients. A logistic regression framework was used to build a risk prediction model for xerostomia. External validation was performed using an independent data set to test the prediction power. A total of 12 682 patients were included in this analysis (54.3%, females). Xerostomia was reported by 12.2% of patients. The proportion of people reporting xerostomia was higher among those who were taking more medications (OR = 1.11, 95% CI = 1.08-1.13) or recreational drug users (OR = 1.4, 95% CI = 1.1-1.9). Rheumatic diseases (OR = 2.17, 95% CI = 1.88-2.51), psychiatric diseases (OR = 2.34, 95% CI = 2.05-2.68), eating disorders (OR = 2.28, 95% CI = 1.55-3.36) and radiotherapy (OR = 2.00, 95% CI = 1.43-2.80) were good predictors of xerostomia. For the test model performance, the ROC-AUC was 0.816 and in the external validation sample, the ROC-AUC was 0.799. The xerostomia risk prediction model had high accuracy and discriminated between high- and low-risk individuals. Clinicians could use this model to identify the classes of medications and systemic diseases associated with xerostomia.

Sparing the region of the salivary gland containing stem cells preserves saliva production after radiotherapy for head and neck cancer.

Each year, 500,000 patients are treated with radiotherapy for head and neck cancer, resulting in relatively high survival rates. However, in 40% of patients, quality of life is severely compromised because of radiation-induced impairment of salivary gland function and consequent xerostomia (dry mouth). New radiation treatment technologies enable sparing of parts of the salivary glands. We have determined the parts of the major salivary gland, the parotid gland, that need to be spared to ensure that the gland continues to produce saliva after irradiation treatment. In mice, rats, and humans, we showed that stem and progenitor cells reside in the region of the parotid gland containing the major ducts. We demonstrated in rats that inclusion of the ducts in the radiation field led to loss of regenerative capacity, resulting in long-term gland dysfunction with reduced saliva production. Then we showed in a cohort of patients with head and neck cancer that the radiation dose to the region of the salivary gland containing the stem/progenitor cells predicted the function of the salivary glands one year after radiotherapy. Finally, we showed that this region of the salivary gland could be spared during radiotherapy, thus reducing the risk of post-radiotherapy xerostomia.

MO‐G‐304‐01: FEATURED PRESENTATION: Expanding the Knowledge Base for Data‐Driven Treatment Planning: Incorporating Patient Outcome Models

Purpose:To extend the capabilities of knowledge‐based treatment planning beyond simple dose queries by incorporating validated patient outcome models.Methods:From an analytic, relational database of 684 head and neck cancer patients, 372 patients were identified having dose data for both left and right parotid glands as well as baseline and follow‐up xerostomia assessments. For each existing patient, knowledge‐based treatment planning was simulated for by querying the dose‐volume histograms and geometric shape relationships (overlap volume histograms) for all other patients. Dose predictions were captured at normalized volume thresholds (NVT) of 0%, 10%, 20, 30%, 40%, 50%, and 85% and were compared with the actual achieved doses using the Wilcoxon signed‐rank test. Next, a logistic regression model was used to predict the maximum severity of xerostomia up to three months following radiotherapy. Baseline xerostomia scores were subtracted from follow‐up assessments and were also included in the model. The relative risks from predicted doses and actual doses were computed and compared.Results:The predicted doses for both parotid glands were significantly less than the achieved doses (p < 0.0001), with differences ranging from 830 cGy ± 1270 cGy (0% NVT) to 1673 cGy ± 1197 cGy (30% NVT). The modelled risk of xerostomia ranged from 54% to 64% for achieved doses and from 33% to 51% for the dose predictions. Relative risks varied from 1.24 to 1.87, with maximum relative risk occurring at 85% NVT.Conclusions:Data‐driven generation of treatment planning objectives without consideration of the underlying normal tissue complication probability may Result in inferior plans, even if quality metrics indicate otherwise. Inclusion of complication models in knowledge‐based treatment planning is necessary in order to close the feedback loop between radiotherapy treatments and patient outcomes. Future work includes advancing and validating complication models in the context of knowledge‐based treatment planning.This work is supported by Philips Radiation Oncology Systems.

The Parotid Gland is an Underrecognized Organ at Risk for Craniospinal Irradiation.

Current craniospinal irradiation (CSI) protocols do not include the parotid gland as an organ at risk, potentially leading to late effects of xerostomia and secondary parotid malignancies. We analyzed the effect of CSI treatment parameters on parotid dose. We retrospectively reviewed 50 consecutive patients treated with CSI to an intracranial dose >26 Gy. Parotid dose was compared to a Radiation Therapy Oncology Group (RTOG) dose constraint (at least 1 parotid with mean dose <26 Gy). The effects of CSI dose (≤24 Gy vs 24 Gy), volumetric-modulated arc therapy (VMAT) versus 3-dimensional (3D) CSI technique, boost dose (≤24 Gy vs 24 Gy), supratentorial versus infratentorial boost location, intensity-modulated radiation therapy (IMRT)-based versus 3D boost technique, supine versus prone position, and age on parotid dose were analyzed using multivariate regression analysis. The RTOG parotid dose constraint was exceeded in 22 (44%) of 50 patients. On multivariate regression analysis, lower CSI dose and VMAT CSI technique were associated with reduced parotid dose for the CSI fields. For the boost fields, lower boost dose and supratentorial boost location were associated with lower parotid dose. All 5 patients who underwent VMAT CSI met dose constraints. Furthermore, for infratentorial lesions with a total (CSI plus boost) dose prescription dose >50 Gy (n = 24), 11 of 16 patients who received low-dose CSI (18-23.4 Gy) were able to meet dose constraints, when compared to only 2 of 8 patients who received high dose CSI (36 Gy). Given the large number of patients exceeding the parotid dose constraint, the parotid gland should be considered an organ at risk. CSI dose de-escalation and IMRT-based CSI techniques may minimize the risk of xerostomia.

Impact of head and neck cancer adaptive radiotherapy to spare the parotid glands and decrease the risk of xerostomia.

BackgroundLarge anatomical variations occur during the course of intensity-modulated radiation therapy (IMRT) for locally advanced head and neck cancer (LAHNC). The risks are therefore a parotid glands (PG) overdose and a xerostomia increase.The purposes of the study were to estimate:- the PG overdose and the xerostomia risk increase during a “standard” IMRT (IMRTstd);- the benefits of an adaptive IMRT (ART) with weekly replanning to spare the PGs and limit the risk of xerostomia.Material and methodsFifteen patients received radical IMRT (70 Gy) for LAHNC. Weekly CTs were used to estimate the dose distributions delivered during the treatment, corresponding either to the initial planning (IMRTstd) or to weekly replanning (ART). PGs dose were recalculated at the fraction, from the weekly CTs. PG cumulated doses were then estimated using deformable image registration. The following PG doses were compared: pre-treatment planned dose, per-treatment IMRTstd and ART. The corresponding estimated risks of xerostomia were also compared. Correlations between anatomical markers and dose differences were searched.ResultsCompared to the initial planning, a PG overdose was observed during IMRTstd for 59% of the PGs, with an average increase of 3.7 Gy (10.0 Gy maximum) for the mean dose, and of 8.2% (23.9% maximum) for the risk of xerostomia. Compared to the initial planning, weekly replanning reduced the PG mean dose for all the patients (p < 0.05). In the overirradiated PG group, weekly replanning reduced the mean dose by 5.1 Gy (12.2 Gy maximum) and the absolute risk of xerostomia by 11% (p < 0.01) (30% maximum). The PG overdose and the dosimetric benefit of replanning increased with the tumor shrinkage and the neck thickness reduction (p < 0.001).ConclusionDuring the course of LAHNC IMRT, around 60% of the PGs are overdosed of 4 Gy. Weekly replanning decreased the PG mean dose by 5 Gy, and therefore by 11% the xerostomia risk.

Texture analysis for the assessment of structural changes in parotid glands induced by radiotherapy

Background and purposeDuring radiotherapy (RT) for head-and-neck cancer, parotid glands undergo significant anatomic, functional and structural changes which could characterize pre-clinical signs of an increased risk of xerostomia. Texture analysis is proposed to assess structural changes of parotids induced by RT, and to investigate whether early variations of textural parameters (such as mean intensity and fractal dimension) can predict parotid shrinkage at the end of treatment. Material and methodsTextural parameters and volumes of 42 parotids from 21 patients treated with intensity-modulated RT for nasopharyngeal cancer were extracted from CT images. To individuate which parameters changed during RT, a Wilcoxon signed-rank test between textural indices (first and second RT week; first and last RT week) was performed. Discriminant analysis was applied to variations of these parameters in the first two weeks of RT to assess their power in predicting parotid shrinkage at the end of RT. ResultsA significant decrease in mean intensity (1.7HU and 3.8HU after the second and last weeks, respectively) and fractal dimension (0.016 and 0.021) was found. Discriminant analysis, based on volume and fractal dimension, was able to predict the final parotid shrinkage (accuracy of 71.4%). ConclusionTextural features could be used in combination with volume to characterize structural modifications on parotid glands and to predict parotid shrinkage at the end of RT.

Prevalence of Xerostomia and Its Relationship with Underlying Diseases, Medication, and Nutrition: A Descriptive Observational Study

Introduction.– We examined the prevalence of xerostomia and other mouthcomplaints in 223 geriatric outpatients in the Slotervaart Hospital in the Netherlands, and the possible relationship between xerostomia on the one hand andmedication, comorbidity and malnutrition on the other. Methods.– The prevalence of xerostomia and oral symptoms was measured in geriatric outpatients using a questionnaire and the GOHAI (Geriatric Oral Health Assessment Index). Malnutrition was assessedwith theMNA (MiniNutritional Assessment).Medications and comorbidity were recorded. Multiple regression analysis was used to determine the possible causes of xerostomia. Results.– The prevalence of xerostomia and oral symptoms is 45% and 61%, respectively. Xerostomia is associated with the use of benzodiazepines (P0.015) andantidepressants (P0.031).No significant relationshipwas found between xerostomia andmalnutrition. Malnutrition, though,was frequentlyobserved.Geriatric specialists reported oral symptoms in only 4.5% of the patients. Conclusion.– Oral symptoms and xerostomia occur frequently, but are not often recognised. There is a significant correlation between the use of benzodiazepines and antidepressants and the risk of xerostomia. We did not find any relationship between xerostomia and underlying diseases or between xerostomia and malnutrition. We recommend that geriatric patients should be asked whether they have oral symptoms, such as xerostomia and other oral symptoms. Medication, particularly antidepressants and benzodiazepines, should be reviewed and a thorough oral examination should be performed.

Optimizing drug treatment among older people in residential care facilities in Helsinki – A randomized, controlled trial

Introduction.– We examined the prevalence of xerostomia and other mouthcomplaints in 223 geriatric outpatients in the Slotervaart Hospital in the Netherlands, and the possible relationship between xerostomia on the one hand andmedication, comorbidity and malnutrition on the other. Methods.– The prevalence of xerostomia and oral symptoms was measured in geriatric outpatients using a questionnaire and the GOHAI (Geriatric Oral Health Assessment Index). Malnutrition was assessedwith theMNA (MiniNutritional Assessment).Medications and comorbidity were recorded. Multiple regression analysis was used to determine the possible causes of xerostomia. Results.– The prevalence of xerostomia and oral symptoms is 45% and 61%, respectively. Xerostomia is associated with the use of benzodiazepines (P0.015) andantidepressants (P0.031).No significant relationshipwas found between xerostomia andmalnutrition. Malnutrition, though,was frequentlyobserved.Geriatric specialists reported oral symptoms in only 4.5% of the patients. Conclusion.– Oral symptoms and xerostomia occur frequently, but are not often recognised. There is a significant correlation between the use of benzodiazepines and antidepressants and the risk of xerostomia. We did not find any relationship between xerostomia and underlying diseases or between xerostomia and malnutrition. We recommend that geriatric patients should be asked whether they have oral symptoms, such as xerostomia and other oral symptoms. Medication, particularly antidepressants and benzodiazepines, should be reviewed and a thorough oral examination should be performed.

Correlation between perceived experience of caries disease and recorded caries activity among adult patients at a Swedish Public Dental Clinic: A longitudinal study

Objective. To compare patients' perceived experiences of caries activity with recorded longitudinal caries prevalence, consequences of caries and length of recall intervals. Materials and methods. A questionnaire was mailed to 134 caries active (CA) and 40 caries inactive (CI) adult patients at a Swedish Public Dental Clinic. The overall response rate was 69%. The questionnaire included items regarding perceived caries activity, general health, dietary and oral hygiene habits, level of education and socioeconomic status. Questionnaire responses were studied for their association to clinical data extracted from patient dental records. Results. There was a correlation between patient-perceived and documented caries activity for all respondents (rho = 0.65; p < 0.001). CA patients had significantly more perceived caries activity (p < 0.001), decayed teeth (p < 0.001), root fillings (p = 0.001) and extractions (p < 0.001) than CI patients. The mean recall interval was 1.5 years for CA and 2.1 years for CI (p < 0.001). In multiple logistic regression analysis, CA patients were at increased risk for xerostomia (OR = 22.66, p = 0.003), sleep disturbances (OR = 4.36, p = 0.04) and more frequent use of daily extra fluoride (OR = 3.58, p = 0.03). Conclusions. Patient-perceived experience of caries correlated well with recorded caries activity in this group of middle-aged Swedish adults. Individuals with active caries were aware of their disease and made more frequent attempts to reduce caries activity by use of daily extra fluoride. Individual risk-based recall intervals did not seem to eliminate consequences of disease activity such as root fillings and extractions during the follow-up period.

Radiothérapie conformationnelle avec modulation d’intensité dans les cancers de la sphère ORL : éthique et sélection des patients

PurposeIntensity modulated radiotherapy (IMRT) allows a better coverage of the target volume and a better saving of organs at risk with a decrease of toxicity in head and neck cancers. It requires more human labor and materials compared to conformational radiotherapy. If they are insufficient, a selection of the patients receiving IMRT may be necessary, raising an ethical problem. Material and methodsWe collected the motives guiding the choice of the technique of radiotherapy for head and neck cancers during a month of physicists’ shortage. ResultsNineteen patients received IMRT and eight conformational radiotherapy. Conformational irradiation was chosen in palliative and postsurgery treatments, to reduce delay, in laryngeal tumors and re-irradiation. IMRT was preferred for complex target volumes and the localizations at risk of important xerostomia following conformational radiotherapy. These choices were confronted with the bioethics criteria of Beauchamp and Childress. The beneficence justified the use of IMRT or conformational radiotherapy depending on the circumstances. The non-maleficence attempted to decrease the toxicity with IMRT. Justice was questioned by the selection. The autonomy of patients was not totally respected in the choice. ConclusionTo help in the choice of the patients receiving an IMRT in a crisis situation, we proposed a hierarchical organization of selection criteria: complex volumes close to critical organs at risk, localization with high risk of xerostomia, long life expectancy and postoperative delay constraints.

Spraakrevalidatie na een totale laryngectomie

In patients with advanced laryngeal or hypopharyngeal cancer, or in cases when the disease recurs after treatment with (chemo)radiation, a total laryngectomy (TLE) is performed. For them to be able to function properly, speech rehabilitation is of the utmost importancefor these patients. For voice rehabilitation, voice prostheses or an electrolarynx can be used. Esophogus-speech can also be applied. In recent decades, voice prostheses in particular have undergone significant development. They can be considered the standard technique for rehabilitation. For dentists, it is important to realise that the anatomy of these patients has changed. In addition, many have a prior history of radiotherapy and thus an increased risk of xerostomia and osteoradionecrosis. In cases where maxillofacial surgery is indicated, the chance of osteoradionecrosis is higher. If extraction is considered, consultation with a head and neck oncology centre is necessary.

Is There a Clinical Benefit to Adaptive Planning During Tomotherapy in Patients with Head and Neck Cancer at Risk for Xerostomia?

To evaluate the necessity of adaptive planning in helical tomotherapy (TOMO) for head and neck cancer in terms of dosimetric influence on the parotid gland. Thirty-one patients underwent curative TOMO for head and neck cancer from April 2006 to April 2007. For each patient, neck diameter was monitored together with body weight at first cervical spine level through mega-voltage computed tomography during the TOMO course. Ten of 31 patients, with significant weight loss (>5%) and/or neck diameter decrease (>10%), were selected for dosimetric analysis, and parotid dose was recalculated at the fourth and last week of TOMO. Xerostomia was estimated by Radiation Therapy Oncology Group criteria. The median dose was 69.96 Gy (range, 54 to 69.96 Gy) and there was no grade 3 or greater complication. Ten patients with significant neck diameter decrease and/or weight loss showed frequent grade 2 acute xerostomia (P=0.02). The volume percentage of daily fractional dose over 0.75 Gy for the parotid gland (V0.75 Gy) increased by 23.6% at the end of TOMO. For patients with significant anatomic contour change; neck diameter decrease (>10%) or weight loss (>5%), adaptive planning using mega-voltage computed tomography can identify dosimetric changes and reduce deleterious side effects such as xerostomia.

TU-C-BRA-02: The Relevance of the Spatial Distribution of Dose for Complications after Head and Neck and Prostate Radiotherapy

A thorough understanding of the dose‐response of individual organs‐at‐risk is essential for being able to choose the best radiotherapytreatment for a patient. Therefore, the spatial distribution of dose to the rectum, the anal canal and the parotid glands and its role for radiation‐induced late toxicities were assessed by performing a retrospective analysis of data from the randomised controlled trials MRC RT01 and PARSPORT. Interpretable geometrical features were introduced to quantify the spatial distribution of dose and correlations between the dose to the anorectal wall and seven clinically relevant late rectal toxicities were assessed. Novel risk‐factors based on the spatial distribution of dose could be identified for different endpoints. It was demonstrated that the type of dose‐response relationship differed considerably between different endpoints. Rectal bleeding was more strongly correlated to the lateral extent than to any other measure, including the dose‐surface histogram (DSH). The dosimetric measure with the strongest correlation to loose stools and proctitis were longitudinal extent and DSHs respectively. Based on this statistical analysis,dosimetric constraints taking spatial information into account were derived. An interpretable, non‐linear normal‐tissue‐complication‐probability model (NTCP model) explicitly taking spatial information into account was presented and its predictive power was evaluated and compared to NTCP models used in current clinical practice. Our novel NTCP models predicted late rectal toxicities significantly better than conventional models. Using the novel NTCP models 3D dose patterns related to a low risk of complications have been identified. These dose patterns may be useful for optimising and assessing treatment plans, potentially yielding better treatments with a reduced risk of late rectal toxicities. Furthermore, the role of spatial information and clinical risk factors for xerostomia after head‐and‐neck radiotherapy was assessed. Multivariate NTCP models taking the shape and the location of the dose to the parotid glands into account were derived based on data from the PARSPORT trial. Results were externally validated using data from two independent patient cohorts. A “directed” bath‐and‐shower effect was identified, indicating that a high relative concentration of the dose in the medial‐inferior part of the ipsi‐lateral gland and a high skewness of the dose in cranio‐caudal direction in the superficial lobe of the ipsi‐lateral parotid are beneficial for patients in terms of reducing the risk of xerostomia. Our novel NTCP model taking the “directed” bath‐and‐shower effect into account can be used to rank treatment plans more reliably than standard mean‐dose models. We have also shown that it is possible to implement this model in an inverse‐treatment‐planning system and take morphological information into account when generating IMRTtreatment plans. Learning Objectives: 1. Understand issues related to quantifying the spatial distribution of dose to organs‐at risk 2. Understand issues related to generating and validating NTCP models based on these risk‐factors 3. Understand issues related to identifying risk factors related to the spatial distribution of dose

Risk of Xerostomia in Association With the Receipt of Radiation Therapy in Older Patients With Head and Neck Cancer

The purpose of this study was to assess the incidence rate and risk of developing xerostomia in association with the receipt of radiation therapy (RT) among a large population-based cohort of elderly patients diagnosed with head and neck cancer (HNC). The study consisted of 10,387 men and women diagnosed with incident HNC cancer at age 65 years or older from 1991 through 2002, identified from the 16 registries of the Surveillance, Epidemiology and End Results-Medicare linked data. Patients were defined as having xerostomia if there were at least 2 claims (for diagnosis code 527.7) at 30 days apart after the date of HNC diagnosis. Patients receiving RT either with or without chemotherapy had a higher cumulative incidence of developing xerostomia compared with those with neither radiotherapy nor chemotherapy (5.6% and 3.8%, respectively vs. 0.5%) at a median follow-up of 2.4 years. Patients who received RT with concurrent chemotherapy were 9 times more likely to develop xerostomia (hazard ratio = 9.13, 95% confidence interval = 6.68-12.48) compared with patients who received neither RT nor chemotherapy, whereas those who received RT without chemotherapy were over 6 times more likely to develop xerostomia (6.29, 4.72-8.37). The strength of this association was similar when patients were stratified by tumor stage and anatomic tumor site. There was no significant association between the risk of developing xerostomia and ethnicity, marital, and socioeconomic status. Radiation therapy for the treatment of HNC is associated with a significant risk of developing xerostomia regardless of type of surgical treatment rendered, tumor stage, or anatomic tumor site.

Reirradiation with intensity‐modulated radiotherapy in recurrent head and neck cancer

In this retrospective investigation we analyzed outcome and toxicity after intensity-modulated reirradiation of recurrent head and neck cancer. Thirty-eight patients with local recurrent head and neck cancer were evaluated. The median dose of initial radiotherapy was 61 Gy. Reirradiation was carried out with step-and-shoot intensity-modulated radiotherapy (median dose: 49 Gy). Median overall survival was 17 months, and the 1- and 2-year overall survival rates were 63% and 34%. The 1- and 2-year local control rates were 57% and 53%. Distant spread occurred in 34%, and reirradiation induced considerable late toxicity in 21% of the patients. Thirty-two percent showed increased xerostomia after reirradiation. The risk for xerostomia was significantly higher for cumulative mean doses of ≥45 Gy to parotid glands. Considering median cumulative maximum doses of 53 Gy to the spinal cord and 63 Gy to the brainstem, no late toxicities were observed. Reirradiation with intensity-modulated radiotherapy in recurrent head and neck cancer is feasible with acceptable toxicity and yields encouraging rates of local control and overall survival.

Radiotherapy Dose–Volume Effects on Salivary Gland Function

Publications relating parotid dose-volume characteristics to radiotherapy-induced salivary toxicity were reviewed. Late salivary dysfunction has been correlated to the mean parotid gland dose, with recovery occurring with time. Severe xerostomia (defined as long-term salivary function of <25% of baseline) is usually avoided if at least one parotid gland is spared to a mean dose of less than approximately 20 Gy or if both glands are spared to less than approximately 25 Gy (mean dose). For complex, partial-volume RT patterns (e.g., intensity-modulated radiotherapy), each parotid mean dose should be kept as low as possible, consistent with the desired clinical target volume coverage. A lower parotid mean dose usually results in better function. Submandibular gland sparing also significantly decreases the risk of xerostomia. The currently available predictive models are imprecise, and additional study is required to identify more accurate models of xerostomia risk.

Reducing the Risk of Xerostomia and Mandibular Osteoradionecrosis: The Potential Benefits of Intensity Modulated Radiotherapy in Advanced Oral Cavity Carcinoma

Radiation therapy for squamous cell carcinoma of the oral cavity may be curative, but carries a risk of permanent damage to bone, salivary glands, and other soft tissues. We studied the potential of intensity modulated radiotherapy (IMRT) to improve target volume coverage, and normal tissue sparing for advanced oral cavity carcinoma (OCC). Six patients with advanced OCC requiring bilateral irradiation to the oral cavity and neck were studied. Standard 3D conformal radiotherapy (3DCRT) and inverse-planned IMRT dose distributions were compared by using dose-volume histograms. Doses to organs at risk, including spinal cord, parotid glands, and mandible, were assessed as surrogates of radiation toxicity. PTV1 mean dose was 60.8 ± 0.8 Gy for 3DCRT and 59.8 ± 0.1 Gy for IMRT ( p = 0.04). PTV1 dose range was 24.7 ± 6 Gy for 3DCRT and 15.3 ± 4 Gy for IMRT ( p = 0.001). PTV2 mean dose was 54.5 ± 0.8 Gy for 3DCRT and for IMRT was 54.2 ± 0.2 Gy ( p = 0.34). PTV2 dose range was improved by IMRT (7.8 ± 3.2 Gy vs. 30.7 ± 12.8 Gy, p = 0.006). Homogeneity index (HI) values for PTV2 were closer to unity using IMRT ( p = 0.0003). Mean parotid doses were 25.6 ± 2.7 Gy for IMRT and 42.0 ± 8.8 Gy with 3DCRT ( p = 0.002). The parotid V30 in all IMRT plans was <45%. The mandible V50, V55, and V60 were significantly lower for the IMRT plans. Maximum spinal cord and brain stem doses were similar for the 2 techniques. IMRT provided superior target volume dose homogeneity and sparing of organs at risk. The magnitude of reductions in dose to the salivary glands and mandible are likely to translate into reduced incidence of xerostomia and osteoradionecrosis for patients with OCC.

Is there a Potential Benefit of Adaptive Planning during Tomotherapy in Head and Neck Cancer Patients at Risk for Xerostomia?

The purpose of this study is to evaluate dosimetric differences of parotid gland and development of xerostomia due to anatomic changes in head and neck cancer patients treated with helical tomotherapy using adaptive planning application.

O12 Reducing the risk of xerostomia and mandibular osteoradionecrosis: the potential benefits of Intensity Modulated Radiotherapy in advanced oral cavity carcinoma

O12 Reducing the risk of xerostomia and mandibular osteoradionecrosis: the potential benefits of Intensity Modulated Radiotherapy in advanced oral cavity carcinoma