Parotid gland sparing in patients undergoing bilateral head and neck irradiation: techniques and early results

Clinical factors associated with severe surgical complications in patients with hypopharyngeal cancer: a single-center case-cohort study

BACKGROUND

Surgical complications are a major concern in the surgical treatment of hypopharyngeal cancer.

OBJECTIVE

To identify clinical factors that predispose patients with hypopharyngeal cancer to severe surgical complications.

MATERIALS AND METHODS

The data of 449 patients who were underwent surgery as a part of the initial treatment with curative intent or as salvage treatment were retrospectively reviewed. The Chi-square test and logistic regression were used to evaluate the association of different factors with severe surgical complications.

RESULTS

The incidence of severe complications was 22% (99/449), and 10 patients (2.2%) experienced rupture of the carotid artery. Multivariate analysis identified T3/4 stage (p = .002, odds ratio (OR) = 1.58, 95% confidence interval (CI) 1.177-2.122), radiotherapy (RT) (p < .001, OR = 2.744, 95% CI 1.680-4.482), diabetes mellitus (DM) (p = .007, OR = 2.697, 95% CI 1.308-5.56), and nonprimary closure (p = .008, OR = 1.992, 95% CI 1.193-3.327) as significant risk factors for severe surgical complications.

CONCLUSIONS AND SIGNIFICANCE

T3/4 stage, RT, nonprimary closure, and DM were independent predisposing factors for severe surgical complications in our study population of hypopharyngeal cancer patients. Taking measures to lower the tumor stage and simplify the surgical procedure may be crucial in reducing the incidence of severe surgical complications among these patients.

The Body Mass Index Paradox in Head and Neck Cancer: A Systematic Review and Meta-Analysis

The body mass index (BMI) paradox describes that among patients with certain cancers, higher pretreatment BMI may be associated with improved survival. We examine the impact of BMI on overall survival (OS) in head and neck squamous cell carcinoma (HNSCC) patients. A literature search was performed, and articles using hazard ratios to describe the prognostic impact of BMI on OS in HNSCC were included. Random-effects DerSimonian and Laird methods were employed for meta-analysis. Meta-analysis of OS indicated a lower hazards of death in the overweight (BMI: 25 kg/m2-30 kg/m2) compared to the normal weight (BMI: 18.5 kg/m2-25 kg/m2). This protective relationship loses significance when BMI exceeds 30 kg/m². Underweight patients (BMI < 18.5 kg/m2) demonstrate higher hazards of death compared to normal weight patients. Compared to HNSCC patients with normal weight, being overweight up to a BMI of 30 kg/m² is a positive predictor of OS, while being underweight confers a prognostic disadvantage. Further studies are needed to determine the mechanisms by which increased body mass influences survival outcomes in HNSCC.

Volumetric and Dosimetric Inconstancy of Parotid Glands and Tumor in Head and Neck Cancer during IMRT

The treatment of head and neck cancer using external beam radiotherapy is commonly done with three field techniques, which involves bilateral parallel opposed beams and one anterior lower neck field. Conventional treatment is based on 2D fluoroscopic images where there is no facility to shield the organs at risk like parotid. The most common side effect of such conventional radiotherapy treatment is xerostomia. The incidence of radiotherapy-related xerostomia varies depending on the specific radiotherapy technique used and the dose delivered to the parotid glands. Dosimetric variation in the tumor and normal tissue including parotid glands due to volume shrinkage during intensity modulated radiotherapy is the leading challenges in radiotherapy delivery in head and neck malignancy in terms of acute and late radiation related toxicities. Therefore if the planning target volume and normal tissue anatomy are changing with time during intensity modulated radiotherapy, it would be beneficial and acceptable to adapt our treatment delivery to minimize normal tissue toxicities where it really matters.

Development and Clinical Implementation of an Automated Virtual Integrative Planner for Radiation Therapy of Head and Neck Cancer

Purpose

Head and neck (HN) radiation (RT) treatment planning is complex and resource intensive. Deviations and inconsistent plan quality significantly affect clinical outcomes. We sought to develop a novel automated virtual integrative (AVI) knowledge-based planning application to reduce planning time, increase consistency, and improve baseline quality.

Methods and Materials

An in-house write-enabled script was developed from a library of 668 previously treated HN RT plans. Prospective hazard analysis was performed, and mitigation strategies were implemented before clinical release. The AVI-planner software was retrospectively validated in a cohort of 52 recent HN cases. A physician panel evaluated planning limitations during initial deployment, and feedback was enacted via software refinements. A final second set of plans was generated and evaluated. Kolmogorov-Smirnov test in addition to generalized evaluation metric and weighted experience score were used to compare normal tissue sparing between final AVI planner versus respective clinically treated and historically accepted plans. A t test was used to compare the interactive time, complexity, and monitor units for AVI planner versus manual optimization.

Results

Initially, 86% of plans were acceptable to treat, with 10% minor and 4% major revisions or rejection recommended. Variability was noted in plan quality among HN subsites, with high initial quality for oropharynx and oral cavity plans. Plans needing revisions were comprised of sinonasal, nasopharynx, P-16 negative squamous cell carcinoma unknown primary, or cutaneous primary sites. Normal tissue sparing varied within subsites, but AVI planner significantly lowered mean larynx dose (median, 18.5 vs 19.7 Gy; P < .01) compared with clinical plans. AVI planner significantly reduced interactive optimization time (mean, 2 vs 85 minutes; P < .01).

Conclusions

AVI planner reliably generated clinically acceptable RT plans for oral cavity, salivary, oropharynx, larynx, and hypopharynx cancers. Physician-driven iterative learning processes resulted in favorable evolution in HN RT plan quality with significant time savings and improved consistency using AVI planner.

Evaluation of halitosis parameters in patients undergoing head and neck radiotherapy

OBJECTIVES

To assess halitosis parameters using OralChromaTM and the correlation with salivary flow, oral hygiene index, radiation dose, and tongue-coating index among irradiated head-and-neck cancer patients compared to patients without cancer.

MATERIALS AND METHODS

This cross-sectional study enrolled irradiated and non-irradiated patients divided into two groups. Hydrogen sulphide, methyl mercaptan, and dimethy sulphide (DMS) levels were measured using a gas chromatograph, and sialometry was performed. The tongue-coating index and simplified oral hygiene index were also assessed.

RESULTS

Thirty-eight patients were allocated to each group. Volatile sulphur compound levels were above the thresholds in both groups. Non-irradiated individuals showed higher levels of hydrogen sulphide and dimethyl sulphide. Patients with asialia had an inexpressive tongue-coating index and increased dimethyl sulphide levels. A decrease in salivary flow rate was followed by a significant increase in volatile sulphur compound levels. Higher doses of radiation to the submandibular salivary glands were associated with higher concentrations of sulphide and methyl mercaptan.

CONCLUSIONS

Head and neck radiotherapy may be important in the development of halitosis. Irradiated patients with asialia presented insignificant lingual biofilm. Consequently, lower levels of volatile sulphur compounds were detected in this group. Asialia, a severe radiation-induced hyposalivation, impacted the levels of DMS (extraoral origin).

The Long-Term Recovery of Parotid Glands in Nasopharyngeal Carcinoma Treated by Intensity-Modulated Radiotherapy

Background

Xerostomia is one of the most common adverse events of radiotherapy in head and neck cancer patients. There have been many reports on functional changes of the parotid gland after radiation therapy, but there have been few reports on the volume of the parotid gland and its relationship with oral quality of life (QOL) and even fewer reports on longitudinal change of the parotid gland volume. The purpose of this study was to evaluate the long-term change of the parotid gland volume after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma and the relationship between parotid irradiation dose and xerostomia symptoms.

Methods

We retrospectively analyzed 26 patients with nasopharyngeal cancer treated by IMRT. Longitudinal changes of parotid gland volumes after IMRT were evaluated on CT images. The parotid gland volumes in each period were converted to the ratio to parotid gland volumes before radiotherapy (relative parotid volume). Dunnett’s test was used to evaluate the longitudinal changes in relative parotid volumes at 0-6, 7-18, 19-30, 31-42, 43-54 and 55-66 months after IMRT. We assessed xerostomia 3 years or more after IMRT by measuring the degree of oral moisture using a moisture-checking device (Mucus, Life Co., Ltd.) and oral QOL evaluation by GOHAI (General Oral Health Assessment Index).

Results

The relative parotid volumes during radiotherapy and at 0-6, 7-18, 19-30, 31-42, 43-54 and 55-66 months after IMRT were 75.2 ± 14.3%, 67.2 ± 11.4%, 68.5 ± 15.9%, 72.4 ± 14.8%, 73.0 ± 13.8%, 76.2 ± 17.5%, and 77.1% ± 17.3%, respectively. The parotid volume had recovered significantly at 43-54 and 55-66 months after IMRT, especially in parotids receiving less than 40 Gy as the mean dose. The mean irradiated dose for bilateral parotids showed negative correlations with oral QOL score and oral moisture after a long period.

Conclusions

The parotid volume recovered gradually but had not reached a plateau even 3 years after radiotherapy, especially in parotids receiving less than 40 Gy as the mean dose.

Hypofractionated chemoradiation for head and cancer: Data from the PET NECK trial

There has been increased interest in hypofractionated accelerated chemoradiation for head and neck cancer during the recent first peak of the COVID-19 pandemic. Prospective data regarding this approach from randomised trials is lacking. In the PET NECK study, 564 patients with squamous cell carcinoma of the head and neck receiving definitive chemoradiation were randomised to either planned neck dissection or PET CT scan guided surveillance. In this surgical trial, three radiotherapy fractionation schedules delivered over 7, 6 or 4 weeks were permitted with synchronous chemotherapy. The purpose of this study was to determine efficacy and quality of life outcomes associated with the use of these schedules. Primary local control and overall survival in addition to quality of life measures at immediately post treatment and 6, 12 and 24 months post-treatment were compared between the three fractionation cohorts. In the 525 patients where fractionation data was available, 181 (34%), 288 (55%) and 56 (11%) patients received 68-70 Gy in 34-35 fractions (#), 60-66 Gy in 30# and 55 Gy in 20# respectively. At a minimum follow up of two years following treatment there was no significant difference between the three fractionation schemes in local control, overall survival or any quality of life measure. Despite the obvious limitations of this study, some data is provided to support the use of hypofractionated accelerated chemoradiation to avoid delays in cancer treatment and reduce hospital visits during the peak of a pandemic. Data from on-going randomised trials examining hypofractionated chemoradiation may be useful for selecting fractionation schedules during future pandemics.

Improved Tumor Control Related to Radiotherapy Technological Development for Hypopharyngeal Cancer

OBJECTIVES/HYPOTHESIS

Squamous cell carcinoma of the hypopharynx (SCCHP) is associated with worse survival compared to other head and neck subsites. This report quantifies the impact of technological improvements in radiotherapy (RT) on outcomes over 6 decades.

METHODS

Patients with SCCHP receiving curative-intent treatment between 1962 and 2015 were retrospectively reviewed. Kaplan-Meier analyses of freedom from local recurrence (FFLR), progression-free survival (PFS), and overall survival (OS) were compared across treatment eras and radiation techniques. Multivariable Cox proportional hazards modeling was performed to specify the effect of RT technique.

RESULTS

One hundred thirty-four patients had a median follow-up of 17 months (IQR = 9-38). There were no differences in staging or use of surgery over time, but use of chemotherapy concurrent with RT increased (P < .001) beginning in the 2000s. The 24-month FFLR using two-dimensional RT (2D-RT), three-dimensional conformal RT (3D-CRT), and intensity-modulated RT (IMRT) was 52%, 55%, and 80%, respectively; 24-month PFS was 39%, 46%, and 73%, respectively; and 24-month OS was 27%, 40%, and 68%, respectively. OS (P = .01), PFS (P = .03), and FFLR (P = 0.02) were improved with IMRT over 2D-RT, and FFLR appeared to be improved over 3D-CRT (P = .06). Controlling for chemotherapy use and other major variables, IMRT produced a strong influence over FFLR (adjusted hazard ratio [HR] = 0.2, 95% confidence interval [CI]: 0.0-1.2, P = .08) and a benefit in OS (adjusted HR = 0.1, 95% CI: 0.0-0.4, P = .005).

CONCLUSIONS

Across 6 decades, patient and tumor characteristics remained similar whereas use of chemoradiation increased and IMRT was adopted. The introduction of IMRT was associated with improved FFLR, PFS, and OS, and a reduction in acute toxicity as compared to earlier radiation technologies.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E452-E458, 2021.

Modulated radiotherapy for head and neck carcinomas: an outcome study

Background

To evaluate the survival outcomes and toxicities experienced by non-metastatic head and neck cancer (HNC) patients receiving modulated radiotherapy (RT).

Materials and methods

A total of 608 HNC patients treated consecutively from March 2010 to December 2014 with common subsites (oral cavity, oropharynx, hypopharynx, larynx and nasopharynx) of HNCs formed the study group. Eligible patients included those treated with radical or postoperative RT between March 2010 and December 2014. More than 90% patients received modulated RT [intensity-modulated radiotherapy (IMRT) or volumetric-modulated arc therapy (VMAT)] with concurrent chemotherapy as per stage guidelines. Demographic parameters and disease-related factors were analysed. Disease-free survival (DFS) was calculated from end date of RT till last follow-up or last date of disease control. Overall survival (OS) was calculated from date of registration to last follow-up date if alive. The primary endpoint was survival. The statistical analyses were performed using SPSS version 20.0 and Kaplan–Meier method was used for calculation survival.

Results

Among the evaluable patients, the median age was 60 years (range: 16–93) with male preponderance (male:female – 513:95). Majority were squamous cell carcinoma 93·4% (568/608). The subsites treated were oral cavity 36·8% (224). oropharynx 26·4% (161), larynx 19·7% (120), hypopharynx 10% (62) and nasopharynx 6·4% (41). RT intent was radical in 63·5% (386) and postoperative in 36·5% (222), with 59·5% (362) receiving concurrent chemotherapy. At last follow-up, 348 (57·2%) patients were alive, 169 (27·7%) patients had succumbed to disease and 120 (24·6%) patients had recurrent disease. Out of 120 recurrent cases loco-regional recurrence, nodal recurrence and distant metastases were seen in 62 (51·7%), 25 (20·8%), 33 (27·5%), respectively. In the entire study cohort at 2 year OS and DFS was 80 and 79% whereas 3 years OS and DFS was 70 and 75%, respectively.

Conclusions

In our study, 2 years and 3 years OS and DFS rates are found comparable to the international data with acceptable toxicity profile with the use of modulated RT. It seems to be possible because of stringent departmental protocols and good medical physics support. Our data re-validates need and benefit of advanced RT techniques like IG-IMRT and VMAT for both postoperative and radical HNC treatment at the cost of minimal long-term side effects. Future stringent follow-up and quality of life issues are being considered in a prospective manner.

Early Changes in Serial CBCT-Measured Parotid Gland Biomarkers Predict Chronic Xerostomia After Head and Neck Radiation Therapy

PURPOSE

To determine whether serial cone beam computed tomography (CBCT) images taken during head and neck radiation therapy (HNR) can improve chronic xerostomia prediction.

METHODS AND MATERIALS

In a retrospective analysis, parotid glands (PGs) were delineated on daily kV CBCT images using deformable image registration for 119 HNR patients (60 or 70 Gy in 2 Gy fractions over 6 or 7 weeks). Deformable image registration accuracy for a subset of deformed contours was quantified using the Dice similarity coefficient and mean distance to agreement in comparison with manually drawn contours. Average weekly changes in CBCT-measured mean Hounsfield unit intensity and volume were calculated for each PG relative to week 1. Dose-volume histogram statistics were extracted from each plan, and interactions among dose, volume, and intensity were investigated. Univariable analysis and penalized logistic regression were used to analyze association with observer-rated xerostomia at 1 year after HNR. Models including CBCT delta imaging features were compared with clinical and dose-volume histogram-only models using area under the receiver operating characteristic curve (AUC) for grade ≥1 and grade ≥2 xerostomia prediction.

RESULTS

All patients experienced end-treatment PG volume reduction with mean (range) ipsilateral and contralateral PG shrinkage of 19.6% (0.9%-58.4%) and 17.7% (4.4%-56.3%), respectively. Midtreatment volume change was highly correlated with mean PG dose (r = -0.318, P < 1e^-6). Incidence of grade ≥1 and grade ≥2 xerostomia was 65% and 16%, respectively. For grade ≥1 xerostomia prediction, the delta-imaging model had an AUC of 0.719 (95% confidence interval [CI], 0.603-0.830), compared with 0.709 (95% CI, 0.603-0.815) for the dose/clinical model. For grade ≥2 xerostomia prediction, the dose/clinical model had an AUC of 0.692 (95% CI, 0.615-0.770), and the addition of contralateral PG changes modestly improved predictive performance, with an AUC of 0.776 (0.643-0.912).

CONCLUSIONS

The rate of CBCT-measured PG image feature changes improves prediction over dose alone for chronic xerostomia prediction. Analysis of CBCT images acquired for treatment positioning may provide an inexpensive monitoring system to support toxicity-reducing adaptive radiation therapy.

Contralateral Parotid-Sparing Radiotherapy in Patients with Unilateral Squamous Cell Carcinoma of the Head and Neck: Technical Methodology and Preliminary Results

Aims and background

Radiation-induced permanent xerostomia occurs frequently in patients affected by squamous cell carcinoma of the head and neck treated by parallel opposed lateral fields. An ipsilateral technique by using co-planar multiple-field arrangement was designed to restrict treatment to the primary tumor and neck on the same side for patients with selected lateralized squamous cell carcinoma of the head and neck.

Methods

From November 2001 till December 2002, 30 patients affected by squamous cell carcinoma of tonsillar fossa, retro-molar trigone, alveolar ridge and oropharyngeal lateral wall were included in this investigational trial and treated with an ipsilateral multiple field technique: in detail, oblique opposed two upper half fields were planned ipsilaterally to the squamous cell carcinoma site to cover PTV1 and PTV2, whereas an anterior-lower half field was planned to encompass the lower neck node area above clavicles. On CT scans, the contralateral parotid gland was outlined as organ at risk and the contralateral upper lymph node area was contoured as volume of interest. In selected cases, convergent oblique two wedge-pair half fields were added to opposed oblique two-field technique in order to cover only PTV2: generally, in these patients, PTV1 received 1.8 Gy per fraction and PTV2 2.2 Gy per fraction up to total doses of 54 Gy and 66 Gy, respectively.

Results

Ten patients received radical radiotherapy, 9 patients radical alternating chemo-radiotherapy, and 11 patients adjuvant radiotherapy. At the end of treatment, unilateral confluent mucositis was recorded in 13 (43%) patients and unilateral moist skin epidermolysis in 14 (46%) patients. Six months after the end of radiotherapy, grade 0 xerostomia was recorded in 20 (67%) patients. No patient experienced grade 2+ xerostomia. At a median follow-up of 12 months, 26 (86%) patients were alive and well; 2 patients (6%) developed contralateral neck node failure, both 4 months after the end of ipsilateral radiotherapy.

Conclusions

These results, although preliminary, suggest that by using an ipsilateral radiotherapy technique, symptomatic xerostomia may be avoided in selected patients with lateralized squamous cell carcinoma of the head and neck without an increased short-term risk of contralateral nodal failure.

The Outcome of the First 100 Nasopharyngeal Cancer Patients in Thailand Treated by Helical Tomotherapy

Background

The aim of the study was to analyse of two-year loco-regional failure free survival (LRFFS), distant metastasis free survival (DMFS), overall survival (OS), and toxicity outcomes of the first 100 nasopharyngeal carcinoma patients in Thailand treated by helical tomotherapy.

Patients and methods

Between March 2012 and December 2015, 100 patients with non-metastatic nasopharyngeal carcinoma were treated by helical tomotherapy. All patients were treated by platinum-based concurrent chemoradiotherapy and adjuvant or neo-adjuvant chemotherapy.

Results

The median age was 51 years (interquartile ranges [IQR]: 42.5–57.0). The mean ± SD of D95% of planning target volume (PTV) 70, 59.4 and 54 were 70.2 ± 0.5, 59.8 ± 0.6, and 54.3 ± 0.8 Gy, respectively. The mean ± SD of conformity index, and homogeneity index were 0.89 ± 0.13 and 0.06 ± 0.07. Mean ± SD of D2 % of spinal cord and brainstem were 34.1 ± 4.4 and 53.3 ±6.3 Gy. Mean ± SD of D50 of contralateral and ipsilateral parotid gland were 28.4 ± 6.7 and 38.5 ± 11.2 Gy. At a median follow-up of 33 months (IQR: 25–41), the 2-year LRFFS, DMFS, OS were 94% (95%CI: 87–98%), 96% (95% CI: 89–98%), and 99% (95% CI: 93–100%), respectively. Acute grade 3 dermatitis, pharyngoesophagitis, and mucositis occurred in 5%, 51%, and 37%, respectively. Late pharyngoesophagitis grade 0 and 1 were found in 98% and 2% of patients. Late xerostomia grade 0, 1 and 2 were found in 17%, 78% and 5%, respectively.

Conclusions

Helical tomotherapy offers good dosimetric performance and achieves excellent treatment outcome in nasopharyngeal carcinoma patients.

The effect of parotid gland-sparing intensity-modulated radiotherapy on salivary composition, flow rate and xerostomia measures

OBJECTIVES

To describe parotid gland (PG) saliva organic and inorganic composition and flow rate changes, after curative intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC), and analyse the relationship between PG saliva analytes and xerostomia measures.

METHODS AND MATERIALS

Twenty-six patients recruited to five prospective phase 2 or 3 trials which assessed toxicity and efficacy of IMRT by HNC subsite, provided longitudinal PG saliva. Salivary flow rate, and subjective and objective xerostomia measures were prospectively collected and saliva tested for inorganic and organic analytes. Statistical comparisons of longitudinal analyte changes and analysis for a relationship between dichotomized xerostomia score and saliva analytes were performed.

RESULTS

One hundred and forty-two PG saliva samples from 26 patients were analysed. At 3-6 months after IMRT, stimulated and unstimulated saliva showed significantly decreased flow rate, total protein (TP) secretion rate, phosphate concentration and increased lactoferrin (LF) concentration. Stimulated saliva alone had elevated LF secretion rate and beta-2-microglobulin (B₂ M) concentration with decreased calcium (Ca²⁺ ) and magnesium (Mg²⁺ ) concentrations and Ca²⁺ secretion rate. At >12 months, under stimulated and unstimulated conditions, increased LF concentration and decreased Mg²⁺ and phosphate concentration persisted and, in stimulated saliva, there was decreased potassium (K⁺ ) and Mg²⁺ concentration. Unstimulated TP secretion rate was lower in the presence of high-grade xerostomia. Otherwise, no relationship between xerostomia grade and PG salivary flow rate, TP and Ca²⁺ secretion rate was found.

CONCLUSION

Fewer significant differences in PG saliva analytes >12 months after IMRT indicate good functional recovery. Residual xerostomia after IMRT will only be further reduced by addressing the sparing of subsites of the PG or other salivary gland tissues, in addition to the PG.

IMRT for head and neck cancer: reducing xerostomia and dysphagia

Dysphagia and xerostomia are the main sequellae of chemoradiotherapy for head and neck cancer, and the main factors in reducing long-term patient quality of life. IMRT uses advanced technology to focus the high radiation doses on the targets and avoid irradiation of non-involved tissues. The decisions about sparing organs and tissues whose damage causes xerostomia and dysphagia depends on the evidence for dose-response relationships for the organs causing these sequellae. This paper discusses the evidence for the contribution of radiotherapy to xerostomia via damage of the major salivary glands (parotid and submandibular) and minor salivary glands within the oral cavity, and the contribution of radiotherapy-related effect on important swallowing structures causing dysphagia. Recommendations for dose limits to these organs, based on measurements of xerostomia and dysphagia following radiotherapy, are provided here.

Cytokines in saliva increase in head and neck cancer patients after treatment

OBJECTIVE

Approximately one-third of advanced head and neck squamous cell carcinomas (HNSCCs) recur within 2 years of treatment. Due to ease of collection, saliva is of interest to monitor changes that correlate with treatment. Previously this was a challenge due to xerostomia after conventional radiation. The emergence of gland-sparing radiation has made it possible to collect saliva post-treatment. This study investigated changes in cytokines in saliva pre- and post-treatment to provide foundational knowledge for future studies exploring the use of saliva to monitor treatment response.

STUDY DESIGN

Pre- and post-treatment saliva was evaluated for 8 cytokines by multiplex assay and enzyme-linked immunosorbent assay.

RESULTS

In oropharyngeal HNSCC, secretion of epidermal growth factor (EGF), GROα (Growth-regulated protein alpha), interleukin (IL)-1α, IL-β, IL-6, IL-8, tumor necrosis factor-α, and vascular endothelial growth factor increased significantly post-treatment. In additional patients, significant increases of GR-α and IL-6 were validated, but EGF showed no change.

CONCLUSIONS

The uniqueness of this study is its comparison of salivary cytokines from HNSCC patients pre- and post-treatment.

Accelerated radiotherapy with simultaneous integrated boost fractionation and intensity-modulated radiotherapy for advanced head and neck cancer

Objective

To determine the feasibility and toxicity profile of accelerated radiotherapy with a simultaneous integrated boost fractionation scheme with intensity-modulated radiotherapy (SIB-IMRT) with or without chemotherapy.

Study Design And Setting

Forty-nine patients with advanced head and neck cancer underwent SIB-IMRT. Concomitant chemotherapy was administered in 29 patients.

Results

Grade 3 acute toxicities included 55% mucositis, 20% odynophagia, 12% nausea, 18% hematologic, and 8% skin. There were no grade 4 toxicities or treatment-related deaths. With a median follow-up of 25 months, locoregional control was 83%, and overall survival was 80%. Of patients with grade 3 late toxicities, two patients (4% of the total) required a permanent percutaneous endoscopic gastrostomy tube, and osteonecrosis occurred in one patient (2% of the total).

Conclusions

SIB-IMRT is a feasible technique that shortens the overall treatment time in the radical treatment of patients with advanced head and neck cancer while maintaining acceptable rates of acute toxicity in this study. Although the results are promising, this approach should be considered only in the setting of a clinical trial.

Dose-volume relationships for moderate or severe neck muscle atrophy after intensity-modulated radiotherapy in patients with nasopharyngeal carcinoma

This study aimed to identify the dosimetric parameters and radiation dose tolerances associated with moderate or severe sternocleidomastoid muscle (SCM) atrophy after intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma (NPC). We retrospectively analysed 138 patients treated with IMRT between 2011 and 2012 for whom IMRT treatment plans and pretreatment and 3-year post-IMRT MRI scans were available. The association between mean dose (Dmean), maximum dose (Dmax), VX (% SCM volume that received more than X Gy), DX (dose to X% of the SCM volume) at X values of 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 and SCM atrophy at 3 years after IMRT were analyzed. All dosimetric parameters, except V40, V50 and V80, were significantly associated with moderate or severe SCM atrophy. Multivariate analysis showed that V65 was an independent predictor of moderate or severe SCM atrophy (P < 0.001). Receiver operating characteristic (ROC) curve indicated a V65 of 21.47% (area under ROC curves, 0.732; P < 0.001) was the tolerated dose for moderate or severe SCM atrophy. We suggest a limit of 21.47% for V65 to optimize NPC treatment planning, whilst minimizing the risk of moderate or severe SCM atrophy.

Novel Manganese-Porphyrin Superoxide Dismutase-Mimetic Widens the Therapeutic Margin in a Preclinical Head and Neck Cancer Model

PURPOSE

To test the effects of a novel Mn porphyrin oxidative stress modifier, Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin (MnBuOE), for its radioprotective and radiosensitizing properties in normal tissue versus tumor, respectively.

METHODS AND MATERIALS

Murine oral mucosa and salivary glands were treated with a range of radiation doses with or without MnBuOE to establish the dose-effect curves for mucositis and xerostomia. Radiation injury was quantified by intravital near-infrared imaging of cathepsin activity, assessment of salivation, and histologic analysis. To evaluate effects of MnBuOE on the tumor radiation response, we administered the drug as an adjuvant to fractionated radiation of FaDu xenografts. Again, a range of radiation therapy (RT) doses was administered to establish the radiation dose-effect curve. The 50% tumor control dose values with or without MnBuOE and dose-modifying factor were determined.

RESULTS

MnBuOE protected normal tissue by reducing RT-mediated mucositis, xerostomia, and fibrosis. The dose-modifying factor for protection against xerostomia was 0.77. In contrast, MnBuOE increased tumor local control rates compared with controls. The dose-modifying factor, based on the ratio of 50% tumor control dose values, was 1.3. Immunohistochemistry showed that MnBuOE-treated tumors exhibited a significant influx of M1 tumor-associated macrophages, which provides mechanistic insight into its radiosensitizing effects in tumors.

CONCLUSIONS

MnBuOE widens the therapeutic margin by decreasing the dose of radiation required to control tumor, while increasing normal tissue resistance to RT-mediated injury. This is the first study to quantitatively demonstrate the magnitude of a single drug's ability to radioprotect normal tissue while radiosensitizing tumor.

Acupuncture-Like Transcutaneous Electrical Nerve Stimulation Versus Pilocarpine in Treating Radiation-Induced Xerostomia: Results of RTOG 0537 Phase 3 Study

PURPOSE AND OBJECTIVES

This report presents the analysis of the RTOG 0537 multicenter randomized study that compared acupuncture-like transcutaneous stimulation (ALTENS) with pilocarpine (PC) for relieving radiation-induced xerostomia.

METHODS AND MATERIALS

Eligible patients were randomized to twice-weekly 20-minute ALTENS sessions for 24 sessions during 12 weeks or PC (5 mg 3 times daily for 12 weeks). The primary endpoint was the change in the University of Michigan Xerostomia-Related Quality of Life Scale (XeQOLS) scores from baseline to 9 months from randomization (MFR). Secondary endpoints included basal and citric acid primed whole salivary production (WSP), ratios of positive responders (defined as patients with ≥20% reduction in overall radiation-induced xerostomia symptom burden), and the presence of adverse events based on the Common Terminology Criteria for Adverse Events version 3. An intention-to-treat analysis was conducted.

RESULTS

One hundred forty-eight patients were randomized. Only 96 patients completed the required XeQOLS and were evaluable at 9 MFR (representing merely 68.6% statistical power). Seventy-six patients were evaluable at 15 MFR. The median change in the overall XeQOLS in ALTENS and PC groups at 9 and 15 MFR were -0.53 and -0.27 (P=.45) and -0.6 and -0.47 (P=.21). The corresponding percentages of positive responders were 81% and 72% (P=.34) and 83% and 63% (P=.04). Changes in WSP were not significantly different between the groups. Grade 3 or less adverse events, mostly consisting of grade 1, developed in 20.8% of patients in the ALTENS group and in 61.6% of the PC group.

CONCLUSIONS

The observed effect size was smaller than hypothesized, and statistical power was limited because only 96 of the recruited 148 patients were evaluable. The primary endpoint-the change in radiation-induced xerostomia symptom burden at 9 MFR-was not significantly different between the ALTENS and PC groups. There was significantly less toxicity in patients receiving ALTENS.

Radiotherapeutic management of locally advanced head and neck cancer

Head and neck cancer management has undergone several paradigm shifts for several relevant reasons. From the dismal experience with the use of radiotherapy as the sole modality in the treatment of this group of patients with advanced disease, radiotherapy has been evaluated as an adjuvant for the same group of patients who had undergone successful surgery. Although there is no level 1 evidence to support postoperative adjuvant radiation, several studies have demonstrated that adjuvant radiotherapy reduces the local failures and, thereby, improves survival. Predictors of recurrence after surgical resection are: positive margins of resection; extranodal spread in involved nodes; perineural invasion; and presence of two or more involved regional lymph nodes. Realization of the advantages of a combination of chemotherapy with radiotherapy has had a major impact on the management of these cancers. There is emerging evidence for the use of adjuvant concurrent chemoradiotherapy in the group with high-risk features. Multiple organ conservation strategies in the management of locally advanced head and neck cancers have evolved over the years. However, the meta-analyses of impact of chemotherapy in various settings reveal that concomitant chemoradiotherapy is superior to any of the other regimens. Increasing use of computed tomography, magnetic resonance imaging and positron emission tomography scan images has resulted in better visualization of target volumes and critical structures. Delineation of these structures is of paramount importance and has resulted in a profound change in conformal treatment planning. Better understanding of the physical aspects of delivery of radiotherapy and the advent of modern treatment planning systems have led to the development of conformal techniques. Although the benefit of these techniques on survival have yet to be demonstrated, there is evidence to suggest that they reduce treatment-related toxicities significantly and facilitate dose escalation. Increased knowledge of radiobiology has led to the development of various altered fractionation regimens in the management of locally advanced head and neck cancers. Discovery of cell-cycle kinetics and signal transduction pathways has led to the unearthing of several potential targets for targeted therapy. The epidermal growth factor receptor gene has emerged as the most promising target. The role of biological radiation response modifiers is evolving. All of these approaches to improve the therapeutic gain would be incomplete without evaluating their effect on the quality of life of these patients.

Intensity-modulated radiation therapy for head and neck cancer

In head and neck cancer, intensity-modulated radiation therapy (IMRT) makes the use of electron beams for irradiation of the posterior neck obsolete, inherently performs missing tissue compensation, and allows concave and intentionally nonhomogeneous dose distributions. By clinical use of these physical characteristics, salivary or lacrimal glands, optic pathway and auditory structures can be selectively underdosed and good evidence of decreased radiation toxicity is available. Evidence for increased local control is still lacking. Recurrences are mainly located in the high-dose-prescription regions, suggesting the need for even higher doses in these areas. Image-aided design of IMRT dose distribution is an area of intense research. New positron emission tomography and magnetic resonance imaging developments might allow definition of volumes inside the tumor where treatment failure is most likely to occur. If these volumes are small, focused dose escalation of large magnitude can be attempted and the hypothesis of improved local control by IMRT can be tested.

Current status of IMRT in head and neck cancer

BACKGROUND

IMRT provides highly conformal dose distributions creating non uniform spatial intensity using different segments in the beam.

MATERIAL & METHODS AND RESULTS

Different retrospective studies have shown a high capability of IMRT to treat tumours close to the base of skull. Prospective studies have shown a decrease in xerostomia compared with conventional 3D conformal treatment (3DCRT). Modulation of intensity is performed by the movement of the multileaf collimator (MLC) that can deliver the radiation in different ways, such as static field segments, dynamic field segments and rotational delivery (arc therapy and tomotherapy). There are slight differences among the different techniques in terms of homogeneity, dose conformity and treatment delivery time.

CONCLUSIONS

The best method to deliver IMRT will depend on multiple factors such as deliverability, practicality, user training and plan quality.

Development and evaluation of a Perspex anthropomorphic head and neck phantom for three dimensional conformal radiation therapy (3D-CRT)

Purposes

To design, construct and evaluate an anthropomorphic head and neck phantom for the dosimetric evaluation of 3D-conformal radiotherapy (3D-CRT) dose planning and delivery, for protocols developed by the Radiation Therapy Oncology Group (RTOG).

Materials and methods

An anthropomorphic head and neck phantom was designed and fabricated using Perspex material with delineated planning target volumes (PTVs) and organs at risk (OARs) regions. The phantom was imaged, planned and irradiated conformally by a 3D-CRT plan. Dosimetry within the phantom was assessed using thermoluminescent dosimeters (TLDs). The reproducibility of phantoms and TLD readings were checked by three repeated identical irradiations. Subsequent three clinical 3D-CRT plans for nasopharyngeal patients have been verified using the phantom. Measured doses from each dosimeter were compared with those acquired from the treatment planning system (TPS).

Results

Phantom's measured doses were reproducible with <3·5% standard deviation between the three TLDs’ repeated measurements. Verification of three head and neck 3D-CRT patients’ plans was implemented, and good agreement between measured values and those predicted by TPS was found. The percentage dose difference for TLD readings matched those corresponding to the calculated dose to within 4%.

Conclusion

The good agreement between predicted and measured dose shows that the phantom is a useful and efficient tool for 3D-CRT technique dosimetric verification.

Simultaneous integrated boost-intensity-modulated radiotherapy in head and neck cancer

OBJECTIVES/HYPOTHESIS

To review toxicity and outcomes in patients with head and neck cancer treated with simultaneous integrated boost-intensity-modulated radiotherapy (SIB-IMRT).

STUDY DESIGN

Review of experience with the SIB-IMRT technique.

METHODS

Fifty patients were treated with the SIB-IMRT technique. Two possible schedules of radiation therapy (RT) were used: SIB 70 (70/60/54 in 33 fractions) and SIB 66 (66/60/54 in 33 fractions). Forty-one patients also received chemotherapy.

RESULTS

All but two patients completed treatment as prescribed. No G4 acute toxicity has been reported in our series. We did not observe any G3 to G4 chronic toxicity, apart from one case of cutaneous necrosis. After a median follow-up of 23.3 months (range, 1-60 months), 41 patients (82%) were alive and negative for disease, and one patient (2%) was alive with distant metastases. Eight patients (16%) died, seven because of progressive disease and one for other causes.

CONCLUSIONS

SIB-IMRT is a highly effective and safe technique of RT in the treatment of head and neck cancer.

Analysis of factors influencing the development of xerostomia during intensity-modulated radiotherapy

OBJECTIVES

Factors influencing xerostomia during intensity-modulated radiation therapy (IMRT) were assessed.

METHODS

A 6-week study of 32 head and neck cancer (HNC) patients was performed. Subjects completed the Xerostomia Inventory (XI) and provided stimulated saliva (SS) at baseline, week 2 and at end of IMRT. Influence of SS flow rate (SSFR), calcium and mucin 5b (MUC5b) concentrations and radiation dose on xerostomia was determined.

RESULTS

HNC subjects experienced mean SSFR decline of 36% by visit 2 (N = 27; P = .012) and 57% by visit 3 (N = 20; P = .0004). Concentrations of calcium and MUC5b increased, but not significantly during IMRT (P > .05). Xerostomia correlated most with decreasing salivary flow rate as determined by Spearman correlations (P < .04) and linear mixed models (P < .0001).

CONCLUSIONS

Although IMRT is sparing to the parotid glands, it has an early effect on SSFR and the constituents in saliva in a manner that is associated with the perception of xerostomia.

Multi-institutional comparison of volumetric modulated arc therapy vs. intensity-modulated radiation therapy for head-and-neck cancer: a planning study

Background

Compared to static beam Intensity-Modulated Radiation Therapy (IMRT), the main advantage of Volumetric Modulated Arc Therapy (VMAT) is a shortened delivery time, which leads to improved patient comfort and possibly smaller intra-fraction movements. This study aims at a treatment planner-independent comparison of radiotherapy treatment planning of IMRT and VMAT for head-and-neck cancer performed by several institutes and based on the same CT- and contouring data.

Methods

Five institutes generated IMRT and VMAT plans for five oropharyngeal cancer patients using either Pinnacle³ or Oncentra Masterplan to be delivered on Elekta linear accelerators.

Results

Comparison of VMAT and IMRT plans within the same patient and institute showed significantly better sparing for almost all OARs with VMAT. The average mean dose to the parotid glands and oral cavity was reduced from 27.2 Gy and 39.4 Gy for IMRT to 25.0 Gy and 36.7 Gy for VMAT, respectively. The dose conformity at 95% of the prescribed dose for PTV_boost and PTV_total was 1.45 and 1.62 for IMRT and 1.37 and 1.50 for VMAT, respectively. The average effective delivery time was reduced from 13:15 min for IMRT to 5:54 min for VMAT.

Conclusions

Independently of institution-specific optimization strategies, the quality of the VMAT plans including double arcs was superior to step-and-shoot IMRT plans including 5–9 beam ports, while the effective treatment delivery time was shortened by ~50% with VMAT.

[Intensity modulated radiotherapy for head and neck cancers: ethics and patients selection]

PURPOSE

Intensity 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 METHODS

We collected the motives guiding the choice of the technique of radiotherapy for head and neck cancers during a month of physicists' shortage.

RESULTS

Nineteen 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.

CONCLUSION

To 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.

Comparison of acute toxicities in two primary chemoradiation regimens in the treatment of advanced head and neck squamous cell carcinoma

PURPOSE

The optimal dosage and frequency of platinum-based chemoradiotherapy (CRT) regimen for treating advanced head and neck squamous cell carcinoma remains unresolved. This study aims to compare the toxicity and efficacy of weekly versus more dose-intensive cisplatin-based CRTs.

METHODS

We reviewed 155 stage III/IV head and neck squamous cell carcinoma patients with no evidence of distant metastasis treated with one of two CRT regimens from 2000 to 2010 at Greater Baltimore Medical Center. Twice-daily radiation was provided as a split course over a 45-day period. Regimen A consisted of concomitant cisplatin (30 mg/m2/1 h) weekly for 6 cycles; regimen B consisted of concomitant cisplatin (12 mg/m2/1 h) and 5-fluorouracil (600 mg/m2/20 h) on days 1 through 5 and days 29 through 33. Main outcome measures included acute toxicities (myelosuppression, neurotoxicity, nephrotoxicity, gastrointestinal dysfunction), unplanned hospitalizations, and disease control at 12 months.

RESULTS

Patients on regimen A were much less likely to experience ototoxicity due to their treatment (0% vs. 9.8%, P = 0.04). They were more likely to experience thrombocytopenia acutely (46% vs. 26%, P = 0.02), but the toxicity was not limiting (grade 1–2). No significant differences exist in the incidence of other toxicities or unplanned hospitalizations. At 1 year, 97% of patients on A vs. 86% of patients on regimen B were free of disease (P = 0.11).

CONCLUSIONS

With concurrent radiotherapy, low-dose, single-agent, weekly cisplatin is less likely than higher-dose daily cisplatin plus 5-fluorouracil provided at the beginning and end of treatment to be associated with ototoxicity. The preliminary data suggest at least equivalent efficacy, but longer follow-up is required.

The Preventive and Therapeutic Effect of Acupuncture for Radiation-Induced Xerostomia in Patients With Head and Neck Cancer

Background. Methods currently available to prevent and manage xerostomia which caused by radiotherapy in patients with head and neck caner have limited efficacy. Some studies suggest that acupuncture may be beneficial. Objectives. The authors evaluated the preventive and therapeutic effect of acupuncture for radiation-induced xerostomia among patients with head and neck cancer. Methods. PUBMED, EMBASE, Cochrane Library, CBM, CAJD, Wan Fang database, and VIP Database for Chinese Technical Periodicals were electronically searched, in conjunction with further manual search for relevant articles. Studies that met the inclusion criteria were systematically evaluated. Results. Three randomized controlled trials (RCTs) investigating the therapeutic effect of acupuncture were included. One RCT on the preventive effect of acupuncture was found. Because of the considerable variation among included studies, meta-analysis was not possible. Two included RCTs used placebo controls, and both observed significant improvement in the salivary flow rates between acupuncture and control groups. However, no significant differences were found. Three included RCTs suggested that acupuncture for radiation-induced xerostomia can improve patients’ subjective symptoms. The only study evaluating the preventive effect of acupuncture for radiation-induced xerostomia showed positive changes in salivary flow rates (both unstimulated and stimulated) and dry mouth -related symptoms. Acupuncture treatment was well tolerated by all patients and no severe adverse effects were seen. Conclusions. Insufficient evidence is available to judge whether acupuncture is safe and whether it is effective in preventing or treating radiation-induced xerostomia. Significant research remains to be done before acupuncture can be recommended for routine use in radiation-induced xerostomia.

Clinical evaluation of intensity-modulated radiotherapy for head and neck cancers

Radiotherapy and surgery are the principal curative modalities in treatment of head and neck cancer. Conventional two-dimensional and three-dimensional conformal radiotherapy result in significant side effects and altered quality of life. Intensity-modulated radiotherapy (IMRT) can spare the normal tissues, while delivering a curative dose to the tumour-bearing tissues. This article reviews the current role of IMRT in head and neck cancer from the point of view of normal tissue sparing, and also reviews the current published literature by individual head and neck cancer subsites. In addition, we briefly discuss the role of image guidance in head and neck IMRT, and future directions in this area.

Phase 2 results from Radiation Therapy Oncology Group Study 0537: a phase 2/3 study comparing acupuncture-like transcutaneous electrical nerve stimulation versus pilocarpine in treating early radiation-induced xerostomia

BACKGROUND

In this phase 2 component of a multi-institutional, phase 2/3, randomized trial, the authors assessed the feasibility and preliminary efficacy of acupuncture-like transcutaneous electrical nerve stimulation (ALTENS) in reducing radiation-induced xerostomia.

METHODS

Patients with cancer of the head and neck who were 3 to 24 months from completing radiotherapy with or without chemotherapy (RT ± C) and who were experiencing xerostomia symptoms with basal whole saliva production ≥0.1 mL per minute and were without recurrence were eligible. Patients received twice weekly ALTENS sessions (24 sessions over 12 weeks) using a proprietary electrical stimulation unit. The primary study objective was to assess the feasibility of ALTENS treatment. Patients were considered compliant if 19 of 24 ALTENS sessions were delivered, and the targeted compliance rate was 85%. Secondary objectives measured treatment-related toxicities and the effect of ALTENS on overall radiation-induced xerostomia burden using the University of Michigan Xerostomia-Related Quality of Life Scale (XeQOLS).

RESULTS

Of 48 accrued patients, 47 were evaluable. The median age was 60 years, 84% of patients were men, 70% completed RT ± C for >12 months, and 21% had previously received pilocarpine. Thirty-four patients completed all 24 ALTENS sessions, 9 patients completed 20 to 23 sessions, and 1 patient completed 19 sessions, representing a 94% total compliance rate. Six-month XeQOLS scores were available for 35 patients and indicated that 30 patients (86%) achieved a positive treatment response with a mean ± standard deviation reduction of 35.9% ± 36.1%. Five patients developed grade 1 or 2 gastrointestinal toxicity, and 1 had a grade 1 pain event.

CONCLUSIONS

The current results indicated that ALTENS treatment for radiation-induced xerostomia can be delivered uniformly in a cooperative, multicenter setting and produces possible beneficial treatment response. Given these results, the phase 3 component of this study was initiated.

Radiation-Induced Xerostomia

Xerostomia is a common complication following radiotherapy for head and neck cancers. This has long-term implications on the quality of life of these patients. The better understanding of salivary function and the interaction of radiotherapy dose-volume and fractionation with salivary function has allowed us to intervene with various modalities to prevent or treat this common complication. Thus we present a review of published literature describing the factors affecting xerostomia, its prevention and treatment.

How to cite this article

Baijal G, Kar R, Agarwal JP. Radiation-Induced Xerostomia. Int J Head Neck Surg 2012;3(2): 82-86.

Parotid gland-recovery after radiotherapy in the head and neck region--36 months follow-up of a prospective clinical study

Background

The aim of the present study was to evaluate the recovery potential of the parotid glands after using either 3D-conformal-radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) by sparing one single parotid gland.

Methods

Between 06/2002 and 10/2008, 117 patients with head and neck cancer were included in this prospective, non-randomised clinical study. All patients were treated with curative intent. Salivary gland function was assessed by measuring stimulated salivary flow at the beginning, during and at the end of radiotherapy as well as 1, 6, 12, 24, and 36 months after treatment. Measurements were converted to flow rates and normalized relative to rates before treatment. Mean doses (D_mean) were calculated from dose-volume histograms based on computed tomographies of the parotid glands.

Results

Patients were grouped according to the D_mean of the spared parotid gland having the lowest radiation exposure: Group I - D_mean < 26 Gy (n = 36), group II - D_mean 26-40 Gy (n = 45), and group III - D_mean > 40 Gy (n = 36). 15/117 (13%) patients received IMRT. By using IMRT as compared to 3D-CRT the D_mean of the spared parotid gland could be significantly reduced (D_mean IMRT vs. 3D-CRT: 21.7 vs. 34.4 Gy, p < 0.001). The relative salivary flow rates (RFSR) as a function of the mean parotid dose after 24 and 36 months was in group I 66% and 74%, in group II 56% and 49%, and in group III 31% and 24%, respectively. Multiple linear regression analyses revealed that the parotid gland dose and the tumor site were the independent determinants 12 and 36 months after the end of RT. Patients of group I and II parotid gland function did recover at 12, 24, and 36 months after the end of RT.

Conclusions

If a D_mean < 26 Gy for at least one parotid gland can be achieved then this is sufficient to reach complete recovery of pre-RT salivary flow rates. The radiation volume which depends on tumor site did significantly impact on the D_mean of the parotids, and thus on the saliva flow and recovery of parotid gland.

MRI to quantify early radiation-induced changes in the salivary glands

PURPOSE

We investigated radiation-induced changes in the salivary glands, 6 weeks after RT, using MRI.

MATERIALS AND METHODS

Eighteen oropharyngeal cancer patients were treated with salivary gland sparing IMRT. All patients received a 3T MRI exam before and 6 weeks after the end of RT, including a T(1)-weighted (T(1)w), a T(2)-weighted (T(2)w), and a dynamic contrast-enhanced (DCE) MRI. For both time points separately, the parotid and submandibular glands were delineated on the MR images. Differences in median signal intensity and signal variation within the glands were tested for significance. Correlations were studied between the MR changes and the planned RT dose.

RESULTS

The volume of the glands reduced significantly by 25%. The T(1)w signal decreased by 10% and the T(2)w signal increased by 23%. The k(ep) value decreased, while the v(e) increased. A correlation of the changes in T(2)w signal with the mean dose was found in both glands.

CONCLUSIONS

Overall radiation-induced changes and volume loss were observed in the parotid and submandibular gland using MR. The observed differences indicated an increased water content such as found in oedema. The overall changes could be related to the mean dose, with a slightly greater impact in the high dose area.

Organ-sparing radiation therapy for head and neck cancer

To improve locoregional tumor control and survival in patients with locally advanced head and neck cancer (HNC), therapy is intensified using altered fractionation radiation therapy or concomitant chemotherapy. However, intensification of therapy has been associated with increased acute and late toxic effects. The application of advanced radiation techniques, such as 3D conformal radiation therapy and intensity-modulated radiation therapy, is expected to improve the therapeutic index of radiation therapy for HNC by limiting the dose to critical organs and possibly increasing locoregional tumor control. To date, Review articles have covered the prevention and treatment of radiation-induced xerostomia and dysphagia, but few articles have discussed the prevention of hearing loss, brain necrosis, cranial nerve palsy and osteoradionecrosis of the mandible, which are all potential complications of radiation therapy for HNC. This Review describes the efforts to prevent therapy-related complications by presenting the state of the art evidence regarding advanced radiation therapy technology as an organ-sparing approach.

Sparing the contralateral submandibular gland without compromising PTV coverage by using volumetric modulated arc therapy

BACKGROUND

Salivary gland function decreases after radiation doses of 39 Gy or higher. Currently, submandibular glands are not routinely spared. We implemented a technique for sparing contralateral submandibular glands (CLSM) during contralateral elective neck irradiation without compromising PTV coverage.

METHODS

Volumetric modulated arc therapy (RapidArc™) plans were applied in 31 patients with stage II-IV HNC without contralateral neck metastases, all of whom received elective treatment to contralateral nodal levels II-IV. Group 1 consisted of 21 patients undergoing concurrent chemo-radiotherapy, with elective nodal doses of 57.75 Gy (PTVelect) and 70 Gy to tumor and pathological nodes (PTVboost) in 7 weeks. Group 2 consisted of 10 patients treated with radiotherapy to 54.45 Gy to PTVelect and 70 Gy to PTVboost in 6 weeks. All clinical plans spared the CLSM using individually adapted constraints. For each patient, a second plan was retrospectively generated without CLSM constraints ('non-sparing plan').

RESULTS

PTV coverage was similar for both plans, with 98.7% of PTVelect and 99.2% of PTVboost receiving ≥95% of the prescription dose. The mean CLSM dose in group 1 was 33.2 Gy for clinical plans, versus 50.6 Gy in 'non-sparing plans' (p < 0.001). In group 2, mean CLSM dose was 34.4 Gy for clinical plans, and 46.8 Gy for non-sparing plans (p = 0.002).

CONCLUSIONS

Elective radiotherapy to contralateral nodal levels II-IV using RapidArc consistently limited CLSM doses well below 39 Gy, without compromising PTV-coverage. Future studies will reveal if this extent of dose reduction can reduce patient symptoms.

Recovery of salivary epidermal growth factor in parotid saliva following parotid sparing radiation therapy: a proof-of-principle study

BACKGROUND

Although radiation therapy (RT) causes permanent xerostomia, parotid-sparing radiation therapy (PSRT) ensures recovery of saliva quantity over time. Salivary epidermal growth factor (EGF) is produced primarily by parotid glands.

OBJECTIVES

The aim of this study was to determine whether salivary EGF can be detected in parotid saliva after PSRT and whether protein secretion is time dependent.

STUDY DESIGN

Salivary EGF concentration (pg/mL) was determined by enzyme-linked immunosorbent assay in stimulated parotid saliva before RT and at 3, 6, and 12 months after RT from 22 patients with head and neck cancer treated with PSRT.

RESULTS

Saliva samples were from 17 men and 5 women (age ranges 23-70 years and 46-71 years, respectively). At 6 months after RT, EGF concentration was 407 pg/mL lower than at baseline (P = .045). Twelve months after PSRT, parotid glands produce substantial amounts of EGF and other proteins, eventually approximating pre-RT levels, with recovery of salivary function.

CONCLUSIONS

This proof-of-principle study shows that even proteins in picogram quantities, such as EGF, can be detected in saliva after PSRT.

Parotid-sparing intensity modulated versus conventional radiotherapy in head and neck cancer (PARSPORT): a phase 3 multicentre randomised controlled trial

Background

Xerostomia is the most common late side-effect of radiotherapy to the head and neck. Compared with conventional radiotherapy, intensity-modulated radiotherapy (IMRT) can reduce irradiation of the parotid glands. We assessed the hypothesis that parotid-sparing IMRT reduces the incidence of severe xerostomia.

Methods

We undertook a randomised controlled trial between Jan 21, 2003, and Dec 7, 2007, that compared conventional radiotherapy (control) with parotid-sparing IMRT. We randomly assigned patients with histologically confirmed pharyngeal squamous-cell carcinoma (T1–4, N0–3, M0) at six UK radiotherapy centres between the two radiotherapy techniques (1:1 ratio). A dose of 60 or 65 Gy was prescribed in 30 daily fractions given Monday to Friday. Treatment was not masked. Randomisation was by computer-generated permuted blocks and was stratified by centre and tumour site. Our primary endpoint was the proportion of patients with grade 2 or worse xerostomia at 12 months, as assessed by the Late Effects of Normal Tissue (LENT SOMA) scale. Analyses were done on an intention-to-treat basis, with all patients who had assessments included. Long-term follow-up of patients is ongoing. This study is registered with the International Standard Randomised Controlled Trial register, number ISRCTN48243537.

Findings

47 patients were assigned to each treatment arm. Median follow-up was 44·0 months (IQR 30·0–59·7). Six patients from each group died before 12 months and seven patients from the conventional radiotherapy and two from the IMRT group were not assessed at 12 months. At 12 months xerostomia side-effects were reported in 73 of 82 alive patients; grade 2 or worse xerostomia at 12 months was significantly lower in the IMRT group than in the conventional radiotherapy group (25 [74%; 95% CI 56–87] of 34 patients given conventional radiotherapy vs 15 [38%; 23–55] of 39 given IMRT, p=0·0027). The only recorded acute adverse event of grade 2 or worse that differed significantly between the treatment groups was fatigue, which was more prevalent in the IMRT group (18 [41%; 99% CI 23–61] of 44 patients given conventional radiotherapy vs 35 [74%; 55–89] of 47 given IMRT, p=0·0015). At 24 months, grade 2 or worse xerostomia was significantly less common with IMRT than with conventional radiotherapy (20 [83%; 95% CI 63–95] of 24 patients given conventional radiotherapy vs nine [29%; 14–48] of 31 given IMRT; p<0·0001). At 12 and 24 months, significant benefits were seen in recovery of saliva secretion with IMRT compared with conventional radiotherapy, as were clinically significant improvements in dry-mouth-specific and global quality of life scores. At 24 months, no significant differences were seen between randomised groups in non-xerostomia late toxicities, locoregional control, or overall survival.

Interpretation

Sparing the parotid glands with IMRT significantly reduces the incidence of xerostomia and leads to recovery of saliva secretion and improvements in associated quality of life, and thus strongly supports a role for IMRT in squamous-cell carcinoma of the head and neck.

Funding

Cancer Research UK (CRUK/03/005).

A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: prevalence, severity and impact on quality of life

PURPOSE

This systematic review aimed to assess the literature for prevalence, severity, and impact on quality of life of salivary gland hypofunction and xerostomia induced by cancer therapies.

METHODS

The electronic databases of MEDLINE/PubMed and EMBASE were searched for articles published in English since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies until 2008 inclusive. Two independent reviewers extracted information regarding study design, study population, interventions, outcome measures, results and conclusions for each article.

RESULTS

The inclusion criteria were met by 184 articles covering salivary gland hypofunction and xerostomia induced by conventional, 3D conformal radiotherapy or intensity-modulated radiotherapy in head and neck cancer patients, cancer chemotherapy, total body irradiation/hematopoietic stem cell transplantation, radioactive iodine treatment, and immunotherapy.

CONCLUSIONS

Salivary gland hypofunction and xerostomia are induced by radiotherapy in the head and neck region depending on the cumulative radiation dose to the gland tissue. Treatment focus should be on optimized/new approaches to further reduce the dose to the parotids, and particularly submandibular and minor salivary glands, as these glands are major contributors to moistening of oral tissues. Other cancer treatments also induce salivary gland hypofunction, although to a lesser severity, and in the case of chemotherapy and immunotherapy, the adverse effect is temporary. Fields of sparse literature included pediatric cancer populations, cancer chemotherapy, radioactive iodine treatment, total body irradiation/hematopoietic stem cell transplantation, and immunotherapy.