Impact of dose volume parameters and clinical factors on acute radiation oral mucositis for locally advanced nasopharyngeal carcinoma patients treated with concurrent intensity-modulated radiation therapy and chemoradiotherapy

Impact of dose volume parameters and clinical characteristics on radiation-induced acute oral mucositis for head and neck cancer patients treated with carbon-ion radiotherapy dose volume outcome analysis

OBJECTIVES

To assess the predictive value of different dosimetric parameters for acute radiation oral mucositis (ROM) in head and neck cancer (HNCs) patients treated with carbon-ion radiotherapy (CIRT).

METHODS

44 patients with HNCs treated with CIRT were evaluated for acute ROM which was defined as severe when the score ≥3 (acute ROM was scored prospectively using the Radiation Therapy Oncology Group (RTOG) score system). Predictive dosimetric factors were identified by using univariate and multivariate analysis.

RESULTS

Male gender, weight loss >5%, and total dose/fractions were related factors to severe ROM. In multivariate analysis, grade ≥3 ROM was significantly related to the Dmax, D10, D15, and D20 (P < 0.05, respectively). As the receiver operating characteristics (ROC) curve shows, the area under the curve (AUC) for D10 was 0.77 (p = 0.003), and the cutoff value was 51.06 Gy (RBE); The AUC for D15 was 0.75 (p = 0.006), and the cutoff value was 42.82 Gy (RBE); The AUC for D20 was 0.74 (p = 0.009), and the cutoff value was 30.45 Gy (RBE); The AUC for Dmax was 0.81 (p < 0.001), and the cutoff value was 69.33 Gy (RBE).

CONCLUSION

Male gender, weight loss, and total dose/fractions were significantly association with ROM. Dmax, D10, D15 and D20 were identified as the most valuable predictor and we suggest a Dmax limit of 69.33 Gy (RBE), D10 limit of 51.06 Gy (RBE), D15 limit of 42.82 Gy (RBE), and D20 limit of 30.45 Gy (RBE) and for oral mucosa.

Toxicity profile of patients treated with proton and carbon-ion therapy for primary nasopharyngeal carcinoma: A systematic review and meta-analysis

BACKGROUND

Proton and carbon-ion therapy may spare normal tissues in regions with many critical structures surrounding the target volume. As toxicity outcome data are emerging, we aimed to synthesize the published data for the toxicity outcomes of proton or carbon-ion therapy (together known as particle beam therapy [PBT]) for primary nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

We searched PubMed and Scopus electronic databases to identify original studies reporting toxicity outcomes following PBT of primary NPC. Quality assessment was performed using NIH's Quality Assessment Tool. Reports were extracted for information on demographics, main results, and clinical and dose factors correlates. Meta-analysis was performed using the random-effects model.

RESULTS

Twelve studies were selected (six using mixed particle-photon beams, five performed comparisons to photon-based therapy). The pooled event rates for acute grade ≥2 toxicities mucositis, dermatitis, xerostomia weight loss are 46% (95% confidence interval [95% CI]-29%-64%, I2 = 87%), 47% (95% CI-28%-67%, I2 = 87%), 16% (95% CI-9%-29%, I2 = 76%), and 36% (95% CI-27%-47%, I2 = 45%), respectively. Only one late endpoint (xerostomia grade ≥2) has sufficient data for analysis with pooled event rate of 9% (95% CI-3%-29%, I2 = 77%), lower than intensity-modulated radiotherapy 27% (95% CI-10%-54%, I2 = 95%). For most endpoints with significant differences between the PBT and photon-based therapies, PBT resulted in better outcomes. In two studies where dose distribution was studied, doses to the organs at risk were independent risk factors for toxicities.

CONCLUSION

PBT may reduce the risk of acute toxicities for patients treated for primary NPC, likely due to dose reduction to critical structures. The pooled event rate for toxicities derived in this study can be a guide for patient counseling.

Multi-trajectories of health-related quality of life and their associated factors in patients with nasopharyngeal carcinoma: A longitudinal study

BACKGROUND

The trajectories of health-related quality of life (HRQoL) of nasopharyngeal carcinoma (NPC) during and after the treatment along with their associated factors are seldom investigated in longitudinal studies. This study aims to investigate the longitudinal trajectories of HRQoL over time and their associated factors in patients with newly diagnosed NPC.

METHODS

Between July 2018 and September 2019, a total of 500 patients were finally involved in this study. HRQoL was measured at four time points, from before treatment to the follow-up period after treatment. Group-based multi-trajectory modeling was applied to identify trajectories of five HRQoL functioning domains during the longitudinal period. Multinomial logistic regression models were applied to investigate potential independent factors associated with the multi-trajectory groups.

RESULTS

We identified four distinct multi-trajectory groups, including the "initially lowest functioning" group (19.8%), the "initially lower functioning" group (20.8%), the "initially higher functioning" group (46.0%), and the "consistently highest functioning" group (13.4%). Patients who were older than 45 years or had T4 stage disease were more likely to be in the "initially lowest functioning" group, while those with EBV DNA ≥ 1500 copies/mL before the treatment were more likely to be in the "initially lowest functioning" or the "initially lower functioning" groups.

CONCLUSIONS

We report the presence of heterogeneity in HRQoL trajectories among patients with NPC, and found that older age, advanced T stage, and higher EBV DNA level before treatment were significantly associated with poor HRQoL trajectories. Further studies are needed to examine the generalizability of these identified HRQoL trajectories and their associations with psychosocial and survival outcomes.

A randomized, controlled trial to investigate cognitive behavioral therapy in prevention and treatment of acute oral mucositis in patients with locoregional advanced nasopharyngeal carcinoma undergoing chemoradiotherapy

Purpose

Oral mucositis is a common side effect of concurrent chemoradiotherapy (CCRT). This study aimed to determine whether cognitive behavioral therapy (CBT) could help prevent oral mucositis during chemoradiation therapy for locoregional advanced nasopharyngeal carcinoma (LA-NPC).

Methods and materials

Between July 15, 2020, and January 31, 2022, a randomized controlled phase II trial was conducted. Eligible patients (N=282, 18-70 years old) with pathologically diagnosed LA-NPC were randomly assigned to receive CBT or treatment as usual (TAU) during CCRT (computer-block randomization, 1:1). The primary endpoints were the incidence and latency of oral mucositis.

Results

The incidence of oral mucositis was significantly lower in the CBT group (84.8%; 95% confidence interval [CI], 78.7%-90.9%) than in the TAU group (98.6%; 95% CI, 96.6%-100%; P<0.001). The median latency period was 26 days and 15 days in the CBT and TAU groups, respectively (hazard ratio, 0.16; 95% CI, 0.12-0.22; P<0.001). CBT significantly reduced ≥ grade 3 oral mucositis (71.9% vs. 22.5%, P<0.001), dry mouth (10.8% vs. 3.7%, P=0.021), dysphagia (18% vs. 5.1%, P=0.001), and oral pain (10% vs. 3.6%, P=0.034) compared with TAU. Patients receiving CBT and TAU during CCRT had similar short-term response rates.

Conclusions

CBT reduced the occurrence, latency, and severity of oral mucositis in patients with LA-NPC during CCRT.

Effects of induction chemotherapy on nutrition status in locally advanced nasopharyngeal carcinoma: a multicentre prospective study

BACKGROUND

Induction chemotherapy (IC) and concurrent chemoradiotherapy (CCRT) is the standard of care for locoregionally advanced nasopharyngeal carcinoma (LA-NPC). This intensive treatment regimen increases acute toxicities, which could negatively impact patients' nutritional status. We conducted this prospective, multicentre trial to investigate the effects of IC and CCRT on nutritional status in LA-NPC patients, so as to provide evidence for further study of nutritional intervention, which was registered in ClinicalTrials.gov (NCT02575547).

METHODS

Patients with biopsy-proven NPC and planned for IC + CCRT were recruited. IC entailed two cycles of 3-weekly docetaxel 75 mg/m² and cisplatin 75 mg/m² ; CCRT entailed two to three cycles of 3-weekly cisplatin 100 mg/m² depending on the duration of radiotherapy. Nutritional status and quality of life (QoL) were assessed pre-IC, post-cycles one and two of IC, W4 and W7 of CCRT. Primary endpoint was the cumulative proportion of ≥ 5.0% weight loss (WL_5.0 ) by the end of treatment (W7-CCRT). Secondary endpoints included body mass index, NRS2002 and PG-SGA scores, QoL, hypoalbuminaemia, treatment compliance, acute and late toxicities and survivals. The associations between primary and secondary endpoints were also evaluated.

RESULTS

One hundred and seventy-one patients were enrolled. Median follow-up was 67.4 (IQR: 64.1-71.2) months. 97.7% (167/171) patients completed two cycles of IC, and 87.7% (150/171) completed at least two cycles of concurrent chemotherapy; all, except one patient (0.6%), completed IMRT. WL was minimal during IC (median of 0.0%), but increased sharply at W4-CCRT (median of 4.0% [IQR: 0.0-7.0%]) and peaked at W7-CCRT (median of 8.5% [IQR: 4.1-11.7%]). 71.9% (123/171) of patients recorded a WL_5.0 by W7-CCRT, which was associated with a higher malnutrition risk (NRS2002 ≥ 3 points: 87.7% [WL ≥ 5.0%] vs 58.7% [WL < 5.0%], P < 0.001) and requirement of nutritional intervention (PG-SGA ≥ 9 points: 82.0% [WL ≥ 5.0%] vs 66.7% [WL < 5.0%], P = 0.038). The median %WL at W7-CCRT was higher in patients who suffered from ≥ G2 mucositis (9.0% vs 6.6%, P = 0.025) and xerostomia (9.1% vs 6.3%, P = 0.003). Besides, patients with cumulative WL_5.0 also reported a higher detriment on QoL at W7-CCRT compared with patients without, with a difference of -8.3 points (95% CI [-15.1, -1.4], P = 0.019).

CONCLUSIONS

We observed a high prevalence of WL among LA-NPC patients who were treated with IC + CCRT, which peaked during CCRT, and had a detriment on patients' QoL. Our data support the need to monitor patient's nutritional status during the later phase of treatment with IC + CCRT and inform on nutritional intervention strategies.

Effect of nutritional status before radiotherapy on radiation-induced acute toxicities in patients with nasopharyngeal carcinoma

BACKGROUND

To investigate the effect of nutritional status on radiation-induced acute toxicities in nasopharyngeal carcinoma (NPC) patients before radiotherapy.

METHODS

Nutritional status of 228 patients with NPC who received intensity-modulated radiotherapy was retrospectively analyzed by modified nutrition index (m-NI). Cumulative grading score of six common acute toxicities were defined as total score for acute toxicities.

RESULTS

M-NI ≤6 is a risk factor for xerostomia (p = 0.016, OR = 0.208, 95% CI 0.058-0.743), oral mucositis (p = 0.016, OR = 0.287, 95% CI 0.104-0.793), dysgeusia (p = 0.001, OR = 0.028, 95% CI 0.004-0.217), and dysphagia (p = 0.015, OR = 0.251, 95% CI 0.083-0.764) as well in patients with NPC. Total score of radiation-induced acute toxicities of patients with malnutrition (13.6 ± 1.7) was significantly higher than that of patients with normal nutrition (12.0 ± 2.4) (t = -5.464, p < 0.001).

CONCLUSIONS

NPC patients with malnutrition before radiotherapy develop more serious dysgeusia, oral mucositis, dysphagia, and xerostomia after intensity-modulated radiotherapy.

Confounding factors in the assessment of oral mucositis in head and neck cancer

Treatment of locally advanced head and neck carcinoma not amenable for surgical resection or resected with high-risk features is usually based on (chemo-)radiation treatment. Oral mucositis represents one of the main side effects of (chemo-)radiation, with an important impact on quality of life and causing approximately 20% of early interruption of treatment, leading to a suboptimal dose administered. Treatment and prevention of oral mucositis have a central role in the therapeutic pathways of head and neck cancer patients but remains quite challenging. Although extensive research is conducted to identify interventions for the management of mucositis, very few interventions had sufficient evidence to generate an international expert consensus. This may be partially explained by confounding factors that could influence the development and assessment of oral mucositis. Little is known about the confounding factors of oral mucositis, which, if not well balanced in an experimental study, could lead to non-solid results. The current paper aims to review the main oral mucositis confounding factors related to head and neck cancer patients.

Pathogenesis and Amelioration of Radiation-Induced Oral Mucositis

OPINION STATEMENT

Oral mucositis (OM) causes significant detriment to patient quality of life. Despite advances in RT, chemotherapy, and surgery for HNC which have led to improved local control and survival, management of certain toxicities such as OM have not kept pace. Numerous strategies have emerged with demonstrable benefit in preventing severe OM. However, ones which are not only effective, but practical and affordable to implement are rare. For example, infusion of growth factors or free radical scavengers, and daily treatment of intra-oral sites with lasers are supported by high-quality evidence but have not become widely adopted. It falls to familiarity of the physician with the available preventative measures and ultimately, patient preference in accepting which strategies for OM amelioration are used. In this review, we present a pathophysiological-based review of prevention techniques available for reducing the incidence and duration of severe OM.

Efficacy of Kanglaite against radiotherapy-induced mucositis in head and neck cancer, a phase II trial

PURPOSE

To explore the potential protective effect of Kanglaite injection against radiotherapy-induced mucositis in patients with head and neck cancer.

PATIENTS AND METHODS

This was an open-label, single-arm, and phase II trial. The primary endpoint was the incidence of grade 3-4 radiation-induced mucositis. The secondary endpoints were hematological toxicity, non-hematological toxicity, nutritional status, and quality of life. All patients received 20g Kanglaite daily concurrently with radiotherapy.

RESULTS

The data of 46 patients were available for analysis. The incidence rates of grade 3 mucositis, pain, dysphagia, and neutropenia were 10.9%, 2.2%, 10.9%, and 6.5%, respectively, while the incidence of grade 4 acute toxicities was zero. The rate of opioid use was 2.2%. Radiotherapy dose reduction was 2.2% and no irradiation field was modified. The nutritional supports were oro-enteral nutritional supplements (13.0%), TPN (10.9%), and feeding tubes (0%) during radiotherapy. After radiotherapy, 52.2% of patients lost weight, and the weight loss was <10%. The mean pain score in the QLQ-H&N35 and QLQ-C30 was <50. Patients had nearly normal physical, emotional, and cognitive functions.

CONCLUSIONS

A low incidence of grade 3-4 radiation-induced mucositis and no severe acute toxic events, with favorable nutritional status and quality of life, were observed in cancer patients after Kanglaite injection. Our findings highlight the need for a prospective, multicenter, and randomized study to investigate the effect of Kanglaite injection on the reduction of radiation-induced mucositis in patients with head and neck cancer.

The broadening scope of oral mucositis and oral ulcerative mucosal toxicities of anticancer therapies

Oral mucositis (OM) is a common, highly symptomatic complication of cancer therapy that affects patients' function, quality of life, and ability to tolerate treatment. In certain patients with cancer, OM is associated with increased mortality. Research on the management of OM is ongoing. Oral mucosal toxicities are also reported in targeted and immune checkpoint inhibitor therapies. The objective of this article is to present current knowledge about the epidemiology, pathogenesis, assessment, risk prediction, and current and developing intervention strategies for OM and other ulcerative mucosal toxicities caused by both conventional and evolving forms of cancer therapy.

Oral mucositis: Current knowledge and future directions

Oral mucositis secondary to head and neck chemoradiation displays a complex molecular pathogenesis involving epithelial and microvascular injury, release of pro-inflammatory cytokines, and host-microbiome communications. These processes lead to oxidative stress and the release of reactive oxygen species that stifle the structural integrity of the oral mucosa, with emergence of erosions and ulcers. The consequences are malnutrition, psychological/psychiatric symptoms, poor quality of life, and occurrence of opportunistic infections. The latter pose a major challenge due to the risk of interruption of anti-neoplastic therapy, tumour recurrence and, ultimately, death. This article aims to present the clinical characteristics, molecular pathogenesis, and an overview of the predisposing factors and current management of oral mucositis. It is anticipated that the future direction of the management of oral mucositis will focus on evidence-based prehabilitation and pre- and per-chemoradiation therapy monitoring.

Noncoplanar Versus Coplanar Intensity-Modulated Radiation Therapy (IMRT) for Protection of the Lip and Buccal Mucosa

Objective:

In this study, by comparing coplanar and noncoplanar intensity-modulated radiation therapy (IMRT) treatment planning in treating tongue cancer, the significance of noncoplanar fields in the protection of the lip and buccal mucosa was determined, and a reasonable solution was selected.

Methods:

Forty-eight tongue cancer patients treated from June 2019 to February 2021 were selected and randomly divided into a coplanar field group and a noncoplanar field group. The mucosal dose limit changed from 15 Gy to 45 Gy for comparison of the two treatment plans. The evaluation indicators (conformal index (CI); homogeneity index (HI); D5, D50, and D98 of the target volume; and the dose of normal tissues) were calculated under different mucosal dose limits. The clinical observation of the lip and buccal mucosa of 48 cases was monitored and graded carefully according to NCI-CTCAE V4.0. Statistical analyses were performed.

Results:

The differences in CI, HI, D98, D50 and D5 between the two groups in the target volume tended to decrease when the mucosal dose limit was less than 30 Gy, with a significant difference (P < 0.05). When the limit exceeded 30 Gy, significant differences in other indicators except CI (P < 0.05) were still noted. In normal tissue, differences in doses between the two groups existed when the mucosal limit was less than 20 Gy, with a significant difference (P < 0.05). When the limit exceeded 20 Gy, no significant difference was noted. Patients in the noncoplanar group showed significantly better results than those in the other group in terms of the radiation-related toxicity of the lip and cheek membrane(P < 0.001).

Conclusions:

Compared with coplanar field radiotherapy, noncoplanar field radiotherapy can effectively reduce the exposure dose to the lip and buccal mucosa. The application of noncoplanar treatment plans exhibits good clinical significance and deserves to be promoted.

Nutritional Status and Its Association With Radiation-Induced Oral Mucositis in Patients With Nasopharyngeal Carcinoma During Radiotherapy: A Prospective Study

Background and Aims

Malnutrition is a concern in patients with nasopharyngeal carcinoma (NPC) during chemoradiotherapy (CRT)/radiotherapy (RT), which is considered to be related with radiation–induced oral mucositis (ROM). The study aimed to evaluate the nutritional status of NPC patients during RT and investigate its association with ROM.

Methods

A prospective study was conducted in NPC patients. Patients were divided into three subgroups (mild, moderate, and severe groups) based on the duration of severe ROM (≥ grade 3). Body weight, body mass index (BMI), albumin, prealbumin, NRS2002, and ROM grade were assessed on a weekly basis before and during CRT/RT. The statistical analysis was performed in the overall group and between three subgroups.

Results

A total of 176 patients were included. In the overall group, body weight and BMI kept decreasing since week 1 of RT, and NRS2002 score and ROM grade increased (p < 0.001). NRS2002 score and prealbumin levels were significantly different between each subgroup (p ≤ 0.046). Significant differences were observed in the proportion of patients receiving enteral nutrition, duration of parenteral nutrition, and total calories provided by nutritional support among three subgroups (p = 0.045–0.001).

Conclusions

Malnutrition occurred early in NPC patients and worsened continuously during RT. ROM was strongly associated with nutritional status. Nutritional support should be provided at the start of RT, especially in patients at high-risk of severe ROM.

Predictive Model and Precaution for Oral Mucositis During Chemo-Radiotherapy in Nasopharyngeal Carcinoma Patients

PURPOSE

To explore risk factors for severe acute oral mucositis of nasopharyngeal carcinoma (NPC) patients receiving chemo-radiotherapy, build predictive models and determine preventive measures.

METHODS AND MATERIALS

Two hundred and seventy NPC patients receiving radical chemo-radiotherapy were included. Oral mucosa structure was contoured by oral cavity contour (OCC) and mucosa surface contour (MSC) methods. Oral mucositis during treatment was prospectively evaluated and divided into severe mucositis group (grade ≥ 3) and non-severe mucositis group (grade < 3) according to RTOG Acute Reaction Scoring System. Nineteen clinical features and nineteen dosimetric parameters were included in analysis, least absolute shrinkage and selection operator (LASSO) logistic regression model was used to construct a risk score (RS) system.

RESULTS

Two predictive models were built based on the two delineation methods. MSC based model is more simplified one, it includes body mass index (BMI) classification before radiation, retropharyngeal lymph node (RLN) area irradiation status and MSC V55%, RS = -1.480 + (0.021 × BMI classification before RT) + (0.126 × RLN irradiation) + (0.052 × MSC V55%). The cut-off of MSC based RS is -1.011, with an area under curve (AUC) of 0.737 (95%CI: 0.672-0.801), a specificity of 0.595 and a sensitivity of 0.786. OCC based model involved more variables, RS= -4.805+ (0.152 × BMI classification before RT) + (0.080 × RT Technique) + (0.097 × Concurrent Nimotuzumab) + (0.163 × RLN irradiation) + (0.028 × OCC V15%) + (0.120 × OCC V60%). The cut-off of OCC based RS is -0.950, with an AUC of 0.767 (95%CI: 0.702-0.831), a specificity of 0.602 and a sensitivity of 0.819. Analysis in testing set shown higher AUC of MSC based model than that of OCC based model (AUC: 0.782 vs 0.553). Analysis in entire set shown AUC in these two method-based models were close (AUC: 0.744 vs 0.717).

CONCLUSION

We constructed two risk score predictive models for severe oral mucositis based on clinical features and dosimetric parameters of nasopharyngeal carcinoma patients receiving chemo-radiotherapy. These models might help to discriminate high risk population in clinical practice that susceptible to severe oral mucositis and individualize treatment plan to prevent it.

Nutritional outcomes after radiotherapy target volume reduction for nasopharyngeal cancer: a Phase III trial

Aim: This study aimed to assess the nutritional status of patients with locoregionally advanced nasopharyngeal cancer, for whom intensity-modulated radiotherapy (IMRT) was planned using their pre- or post-induction chemotherapy (IC) nasopharyngeal gross tumor volume. Materials & methods: 212 cases of stage III-IVb nasopharyngeal cancer were randomized into groups A (n = 97) and B (n = 115). IMRT was planned for groups A and B using pre-IC and post-IC images, respectively. Results: There was a significant decrease in the nutritional parameters of group B compared with those of group A during radiotherapy. Multivariate analysis indicated that the T stage and nasopharyngeal gross tumor volume IMRT-planning protocol were prognostic factors of poor nutritional status. Conclusion: Decreasing the IMRT target volume through IC can improve nutritional status.

Use of Amifostine for Cytoprotection during Radiation Therapy: A Review

BACKGROUND

Radiation therapy is a cornerstone of the therapeutic modalities used in modern oncology. However, it is sometimes limited in its ability to achieve optimal tumor control by radiation-induced normal tissue toxicity. In delivering radiation therapy, a balance must be achieved between maximizing the dose to the tumor and minimizing any injury to the normal tissues. Amifostine was the first Food and Drug Administration (FDA)-approved clinical radiation protector intended to reduce the impact of radiation on normal tissue, lessening its toxicity and potentially allowing for increased tumor dose/control. Despite being FDA-approved almost 20 years ago, Amifostine has yet to achieve widespread clinical use.

SUMMARY

A thorough review of Amifostine's development, mechanism of action, and current clinical status were conducted. A brief history of Amifostine is given, from its development at Walter Reid Institute of Research to its approval for clinical use. The mechanism of action of Amifostine is explored. The results of a complete literature review of all prospective randomized trials to date involving the use of Amifostine in radiation therapy are presented. The results are arranged by treatment site and salient findings discussed. Side effects and complications to consider in using Amifostine are reviewed. Key Messages: Amifostine has been explored as a radiation protectant in most radiation treatment sites. Studies have demonstrated efficacy of Amifostine in all treatment sites reviewed, but results are heterogeneous. The heterogeneity of studies looking at Amifostine as a clinical radiation protectant has precluded a definitive answer on its efficacy. Complicating its clinical use is its toxicity and delivery requirements. Amifostine has largely fallen out of use with the advent of intensity modulated radiation therapy (IMRT). However, side effects with IMRT remain a challenge and concern. The use of Amifostine in the IMRT era has been poorly explored and is worthy of future study.

Tongue surface model can predict radiation tongue mucositis due to intensity-modulated radiation therapy for head and neck cancer

Acute radiation tongue mucositis has a profound effect on talking and eating. We examined whether the dose-volume histogram obtained from the tongue surface model correlates with mucositis severity, and whether it is useful for predicting acute radiation tongue mucositis in patients with head and neck cancer treated with intensity-modulated radiation therapy. Thirty-six patients who received intensity-modulated radiation therapy for head and neck cancer were analysed for acute radiation tongue mucositis according to the Common Terminology Criteria for Adverse Events, version 4.0, as well as the Radiation Therapy Oncology Group scoring systems. The corresponding high-dose locations in anatomical sub-regions in the tongue surface model and the development of high-grade acute radiation tongue mucositis were compared. The mucositis sites coincided with the high-dose anatomical sub-regions in the tongue surface model. There was a clear dose-response relationship between the mean dose to the tongue and the acute radiation tongue mucositis Radiation Therapy Oncology Group grade. According to the dose-volume histogram, patients receiving 16.0-73.0 Gy to the tongue were susceptible to grade 2-3 toxicity. The tongue surface model can predict the site and severity of acute radiation tongue mucositis. In future, radiation treatment plans ccould be optimized using this model.

Multivariable model for predicting acute oral mucositis during combined IMRT and chemotherapy for locally advanced nasopharyngeal cancer patients

INTRODUCTION/OBJECTIVE

Oral and oropharyngeal mucositis (OM) represents amultifactorialand complexinterplayof patient-, tumor-, and treatment-related factors. We aimed to build a predictive model for acute OM for locally advanced nasopharyngeal carcinoma (NPC) patients by combining clinical and dosimetric factors.

MATERIALS/METHODS

A series of consecutive NPC patients treated curatively with IMRT/VMAT + chemotherapy at 70 Gy (2-2.12 Gy/fr) was considered. For each patient, clinical- tumor- and treatment-related data were retrospectively collected. oral cavity (OC) and parotid glands (PG, considered as a single organ) were selected as organs-at-risk (OARs). Acute OM was assessed according to CTCAE v4.0 at baseline and weekly during RT. Two endpoints were considered: grade ≥3 and mean grade ≥1.5. DVHs were reduced to Equivalent Uniform Dose (EUD). Dosimetric and clinical/treatment features selected via LASSO were inserted into a multivariable logistic model. Goodness of fit was evaluated through Hosmer-Lemeshow test and calibration plot.

RESULTS

Data were collected for 132 patients. G ≥ 3 and mean G ≥ 1.5 OM were reported in 40 patients (30%). Analyses resulted in a 3-variables model for G ≥ 3 OM, including OC EUD with n = 0.05 (OR = 1.02), PG EUD with n = 1 (OR = 1.06), BMI ≥ 30 (OR = 3.8, for obese patients), and a single variable model for mean G ≥ 1.5 OM, i.e. OC EUD with n = 1 (mean dose) (OR = 1.07). Calibration was good in both cases.

CONCLUSION

OC mean dose was found to impact most on OM duration (mean G ≥ 1.5), while G ≥ 3 OM was associated to a synergic effect between PG mean dose and high dose received by small OC volumes, with BMI acting as a dose-modifying factor.

Radiation-induced gray matter atrophy in patients with nasopharyngeal carcinoma after intensity modulated radiotherapy: a MRI magnetic resonance imaging voxel-based morphometry study

Background

Gray matter (GM) damage after radiotherapy (RT) in nasopharyngeal carcinoma (NPC) patients can result in cognitive impairment, while there may be no visible brain tissue change according to the conventional magnetic resonance imaging (MRI). This study investigated radiation-induced GM volume differences between NPC patients who received RT and those who did not.

Methods

High-resolution brain structural MRI data from two groups of patients were acquired. The pre-RT group was composed of 56 newly diagnosed but not yet medically treated NPC patients, while the after-RT group consisted of 40 NPC patients who had completed RT more than 1 year ago. Voxel-based morphometry (VBM) was applied to assess GM volumes. Two sample t-test was used to analyze GM volumes voxel-by-voxel using the VBM8 toolbox built in the SPM software. Radiation-induced cortical volume alteration in all NPC patients after RT and dosimetry of 36 patients were analyzed.

Results

Compared to pre-treatment group, cortical volumes of GM were significantly smaller in the left hippocampus, the right pulvinar and the right middle temporal gyrus (MTG, P<0.001, AlphaSim correction, cluster size ≥157). The mean dose (D_mean) for bilateral hippocampal heads were significantly higher than other different parts of the brain (P<0.001). No significant correlations between the GM volume in any brain regions and the mean dose of corresponding position of these brain regions were observed (P>0.05).

Conclusions

Radiation to the NPC patients can not only induce damage of the hippocampus, but also other secondary damages of GM.

Revisiting the dose constraints for head and neck OARs in the current era of IMRT

Head and neck cancer poses a particular challenge in radiation therapy, whilst being an effective treatment modality it requires very high doses of radiation to provide effective therapy. This is further complicated by the fact that the head and neck region contains a large number of radiosensitive tissues, often resulting in patients experiencing debilitating normal tissue complications. In the era of intensity-modulated radiation therapy (IMRT) treatments can be delivered using non-uniform dose distributions selectively aimed at reducing the dose to critical organs-at-risk while still adequately covering the tumor target. Dose-volume constraints for the different risk organs play a vital role in one's ability to devise the best IMRT treatment plan for a head and neck cancer patient. To this end, it is pivotal to have access to the latest and most relevant dose constraints available and as such the goal of this review is to provide a summary of suggested dose-volume constraints for head and neck cancer RT that have been published after the QUANTEC reports were made available in early 2010.