Early evaluation of radiation-induced parotid damage with diffusion kurtosis imaging: a preliminary study

World Workshop on Oral Medicine VIII: Development of a Core Outcome Set for Dry Mouth: A Systematic Review of Outcome Domains for Xerostomia

OBJECTIVE

The purpose of this study was to identify all outcome domains used in clinical studies of xerostomia, that is, subjective sensation of dry mouth. This study is part of the extended project "World Workshop on Oral Medicine Outcomes Initiative for the Direction of Research" to develop a core outcome set for dry mouth.

STUDY DESIGN

A systematic review was performed on MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials databases. All clinical and observational studies that assessed xerostomia in human participants from 2001 to 2021 were included. Information on outcome domains was extracted and mapped to the Core Outcome Measures in Effectiveness Trials taxonomy. Corresponding outcome measures were summarized.

RESULTS

From a total of 34,922 records retrieved, 688 articles involving 122,151 persons with xerostomia were included. There were 16 unique outcome domains and 166 outcome measures extracted. None of these domains or measures were consistently used across all the studies. The severity of xerostomia and physical functioning were the 2 most frequently assessed domains.

CONCLUSION

There is considerable heterogeneity in outcome domains and measures reported in clinical studies of xerostomia. This highlights the need for harmonization of dry mouth assessment to enhance comparability across studies and facilitate the synthesis of robust evidence for managing patients with xerostomia.

Application of Diffusion Kurtosis Imaging in Evaluating Acute Xerostomia in Nasopharyngeal Carcinoma Treated With Induction Chemotherapy Plus Concurrent Chemoradiotherapy

Purpose

The aim of this study was to identify the efficacy of diffusion kurtosis imaging (DKI) in tracking and monitoring the dynamic change of parotid glands (PGs), submandibular glands (SMGs), sublingual glands (SLGs), and acute xerostomia in nasopharyngeal carcinoma (NPC) patients treated with induction chemotherapy (IC) plus concurrent chemoradiotherapy (CCRT).

Methods

The prospective study recruited 42 participants treated with IC+CCRT. All patients underwent DKI scanning six times: before IC, before RT, in the middle of the RT course, immediately after RT, and 1 and 3 months post-RT. Mean diffusion coefficient (MD) and mean kurtosis (MK) of PG, SMG, SLG, saliva flow rate measured under resting (uSFR) and stimulated condition (sSFR), and xerostomia questionnaire (XQ) scores were recorded.

Results

At each time point, sSFR was significantly higher than uSFR (p < 0.05 for all). MD of the salivary glands and XQ scores increased over time while MK, uSFR, and sSFR decreased. After IC, the significant differences were detected in MD and MK of bilateral SMG and MK of the left SLG (p < 0.05 for all), but not in MD and MK of PG, uSFR, sSFR, and XQ scores. After RT, sSFR at 1m-RT decreased significantly (p = 0.03) while no significant differences were detected in uSFR and XQ scores. Moderate-strong correlations were detected in ΔMD-PG-R%, ΔMK-PG-R%, ΔMD-PG-L%, ΔMK-PG-L%, ΔMD-SMG-R%, ΔMK-SMG-R%, ΔMD-SMG-L%, ΔMK-SMG-L%, and ΔMD-SLG-R%, with correlation coefficients (p < 0.05 for all) ranging from 0.401 to 0.714. ΔuSFR% was correlated with ΔMD-SMG% (p = 0.01, r = -0.39), ΔMD-SLG% (p < 0.001, r = -0.532), and ΔMK-SMG% (p < 0.001, r = -0.493). ΔsSFR% correlated with ΔMD-PG% (p = 0.001, r = -0.509), ΔMD-SMG% (p = 0.015, r = -0.221), and ΔMK-PG% (p < 0.001, r = 0.524). ΔXQ% was only correlated with ΔMK-PG% (p = 0.004, r = 0.433).

Conclusion

DKI is a promising tool for tracking and monitoring the acute damage of PG, SMG, and SLG induced by IC+CCRT in NPC patients.

The Role of Patient- and Treatment-Related Factors and Early Functional Imaging in Late Radiation-Induced Xerostomia in Oropharyngeal Cancer Patients

Simple Summary

In the present prospective study, we assessed the role of various Magnetic Resonance Imaging biomarkers combined with self-assessed xerostomia questionnaires and patient- and treatment-related factors, in predicting xerostomia at 12 months after chemoradiotherapy for oropharyngeal squamous cell carcinoma. We hypothesized that the integration of pre-treatment imaging biomarkers, which addresses the tissue heterogeneity and individual variations among patients, could improve the accuracy of conventional prediction models that are based only on dose information, ultimately providing a better understanding of the pathophysiological mechanisms underlying radiation induced salivary dysfunction. The implementation of multifactorial models, driven by machine learning algorithms, may improve prediction accuracy of radiation-induced toxicity and tailor individual treatment options for patients.

Abstract

The advent of quantitative imaging in personalized radiotherapy (RT) has offered the opportunity for a better understanding of individual variations in intrinsic radiosensitivity. We aimed to assess the role of magnetic resonance imaging (MRI) biomarkers, patient-related factors, and treatment-related factors in predicting xerostomia 12 months after RT (XER₁₂) in patients affected by oropharyngeal squamous cell carcinoma (OSCC). Patients with locally advanced OSCC underwent diffusion-weighted imaging (DWI) and dynamic-contrast enhanced MRI at baseline; DWI was repeated at the 10th fraction of RT. The Radiation Therapy Oncology Group (RTOG) toxicity scale was used to evaluate salivary gland toxicity. Xerostomia-related questionnaires (XQs) were administered weekly during and after RT. RTOG toxicity ≥ grade 2 at XER₁₂ was considered as endpoint to build prediction models. A Decision Tree classification learner was applied to build the prediction models following a five-fold cross-validation. Of the 89 patients enrolled, 63 were eligible for analysis. Thirty-six (57.1%) and 21 (33.3%) patients developed grade 1 and grade 2 XER₁₂, respectively. Including only baseline variables, the model based on DCE-MRI and V65 (%) (volume of both glands receiving doses ≥ 65 Gy) had a fair accuracy (77%, 95% CI: 66.5–85.4%). The model based on V65 (%) and XQ-Int_mid (integral of acute XQ scores from the start to the middle of RT) reached the best accuracy (81%, 95% CI: 71–88.7%). In conclusion, non-invasive biomarkers from DCE-MRI, in combination with dosimetric variables and self-assessed acute XQ scores during treatment may help predict grade 2 XER₁₂ with a fair to good accuracy.

Apparent diffusion coefficient measurement of the parotid gland parenchyma

The measurements of apparent diffusion coefficient (ADC) with diffusion weighted magnetic resonance imaging (DW-MRI) is becoming a popular diagnostic and research tool for examination of parotid glands. However, there is little agreement between the reported ADC values of the parotid gland in published literature. In this review 43 studies on ADC measurement of the parotid glands were included. The analyses indicated several possible culprits of the observed ADC discrepancies. For example, DW-MRI examinations under gustatory stimulation gives higher ADC values compared to the unstimulated parotid gland (P=0.003). The diffusion weighting factors (b-values) can either increase (b-value <200 s/mm²) or decrease ADC values (b-values >1,000 s/mm²). The timing of follow-up DW-MRI after radiotherapy (RT) indicates correlation to the found ADC values (R² =0.39). Interestingly, the choice of regions of interest (ROI) appears not to affect the measurements of ADC (P=0.75). It can be concluded that there is a critical need for standardization of ADC measurement of the parotid glands to allow valid inter-study comparisons and eventually to reach consensus on the use of ADC as biomarker.

Radioiodine therapy induced sialadenitis versus chronic idiopathic sialadenitis-Presentation and outcomes

BACKGROUND

This study explores the unique characters of high dose radioactive iodine (RAI) induced chronic sialadenitis.

METHODS

A retrospective study of patients having received salivary endoscopy and followed in our outpatient clinic.

RESULTS

A total of 100 patients met the inclusion criteria, 75 were diagnosed with chronic idiopathic sialoadenitis and 25 with radio-iodine induced sialoadenitis (RIS). The main complaint in both groups was swelling of the parotid gland. Pain, dysphagia, and xerostomia were observed considerably more in the RIS group. During sialo-endoscopy, fibrosis of the Stensen's duct was more common in the RIS group (p = 0.003). RIS patients group generally managed better with interventional endoscopic treatment alone (80% vs. 46%).

CONCLUSION

RIS patients have distinct clinical characteristics. There may be a collateral muscular damage to the masticatory muscles. Fibrosis and parenchymal damage are major findings during sialendoscopy. Sialendoscopy is a safe and efficient treatment for RAI induced sialadenitis.

Early evaluation of radiation-induced parotid damage in patients with nasopharyngeal carcinoma by T2 mapping and mDIXON Quant imaging: initial findings

BACKGROUND

Radiation-induced parotid damage is a common complication in patients with nasopharyngeal carcinoma (NPC) treated with radiotherapy to head and neck region, which severely reduce the life quality of those patients. The aim of this study was to early evaluate the changes of irradiated parotid glands with T2 mapping and mDIXON Quant imaging.

METHODS

Forty-one patients with NPC underwent conventional magnetic resonance imaging for nasopharynx and neck, and T2 mapping and mDIXON Quant imaging for bilateral parotid glands within 2 weeks before radiotherapy (pre-RT), 5 weeks after the beginning of radiotherapy (mid-RT), and 4 weeks after radiotherapy (post-RT). Parotid volume, T2 values, fat fraction (FF) values, and mean radiation dose were recorded and analyzed.

RESULTS

From pre-RT to mid-RT, parotid volume decreased (atrophy rate, 27.0 ± 11.5%), while parotid T2 and FF values increased (change rate, 6.0 ± 6.2% for T2 value and 9.1 ± 9.9% for FF value) significantly. From mid-RT to post-RT, parotid T2 value continuously increased (change rate, 4.6 ± 7.7%), but parotid FF value decreased (change rate, - 9.9 ± 18.2%) significantly. Change rate of parotid T2 value significantly correlated with parotid atrophy rate from pre-RT to post-RT (r = 0.313, P = 0.027). Multiple linear regression analysis showed that parotid T2 value (standardized coefficient [SC] = - 0.259, P = 0.001) and FF value (SC = - 0.320, P = 0.014) negatively correlated with parotid volume, while parotid T2 value positively correlated with MR scan time point (SC = 0.476, P = 0.001) significantly. Parotid T2 and FF values showed excellent reproducibility (intraclass correlation coefficient, 0.935-0.992).

CONCLUSIONS

T2 mapping and mDIXON Quant imaging is useful for noninvasive evaluation of radiation-induced parotid damage.