Prospective Randomized Study of Intensity-Modulated Radiotherapy on Salivary Gland Function in Early-Stage Nasopharyngeal Carcinoma Patients

Kam, Michael Koon Ming; Leung, Sing Fai; Zee, Benny; Chau, R.M.W.; Suen, Joyce; Mo, Frankie; Lai, Manhong; Ho, Rosalie; Cheung, K.Y.; Yu, Brian; Chiu, Samuel K.W.; Choi, Peter; Teo, Peter M.L.; Kwan, W. H.; Chan, Anthony T.C.

doi:10.1200/jco.2007.11.5501

Cited by 662 publications

(437 citation statements)

References 34 publications

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“…It is clear that intensitymodulated radiation therapy (IMRT) has protective effects in parotid gland function, especially in early stages of nasopharyngeal carcinoma. It is also confirmed that .IMRT can protect the funcution of salivary glands in clinical treatment (Pow et al, 2006;Kam et al, 2007). But the follow-up after IMRT treatment, we found that the retention rate of nasopharyngeal carcinoma with local recurrence rate is as high as 30% (Sanguineti et al, 1997).…”

Section: Introductionsupporting

confidence: 70%

Dosimetric Verification for Primary Focal Hypermetabolism of Nasopharyngeal Carcinoma Patients Treated with Dynamic Intensity-modulated Radiation Therapy

Xin

Wang²,

Li³

et al. 2012

Asian Pacific Journal of Cancer Prevention

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Objective: To make sure the feasibility with 18F FDG PET/CT to guided dynamic intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma patients, by dosimetric verification before treatment. Methods: Chose 11 patients in Ⅲ~ⅣA nasopharyngeal carcinoma treated with functional image-guided IMRT and absolute and relative dosimetric verification by Varian 23EX LA, ionization chamber, 2DICA of I'mRT Matrixx and IBA detachable phantom. Drawing outline and making treatment plan were by different imaging techniques (CT and 18F FDG PET/CT). The dose distributions of the various regional were realized by SMART. Results: The absolute mean errors of interest area were 2.39%±0.66 using 0.6cc ice chamber. Results using DTA method, the average relative dose measurements within our protocol (3%, 3 mm) were 87.64% at 300 MU/min in all filed. Conclusions: Dosimetric verification before IMRT is obligatory and necessary. Ionization chamber and 2DICA of I'mRT Matrixx was the effective dosimetric verification tool for primary focal hyper metabolism in functional image-guided dynamic IMRT for nasopharyngeal carcinoma. Our preliminary evidence indicates that functional image-guided dynamic IMRT is feasible.

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Section: Introductionsupporting

confidence: 70%

Dosimetric Verification for Primary Focal Hypermetabolism of Nasopharyngeal Carcinoma Patients Treated with Dynamic Intensity-modulated Radiation Therapy

Xin

Wang²,

Li³

et al. 2012

Asian Pacific Journal of Cancer Prevention

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“…Selective collection of submandibular/sublingual saliva from Wharton's duct orifices. Plots of SMG saliva flow rates vs. mean SMG doses at various post-RT time points (1,3,6,12,18, and 24 months). A.…”

Section: Discussionmentioning

confidence: 99%

“…Even in the studies which demonstrated statistically significant correlations, the correlation coefficients were modest and a substantial variability in the QOL scores could not be explained by the salivary flow rates alone. Two recent randomized studies comparing IMRT to conventional RT for nasopharyngeal cancer demonstrated the dichotomy between the preserved parotid saliva and xerostomia symptoms: Kam et al found that salivary flows, but not patient-reported xerostomia scores, were significantly better following IMRT compared with conventional RT (12), and Pow et al reported substantially higher salivary flow rates in the IMRT group, however, the improvement in symptoms, while statistically significant, was modest (6).…”

Section: Introductionmentioning

confidence: 99%

Dose-Effect Relationships for the Submandibular Salivary Glands and Implications for Their Sparing by Intensity Modulated Radiotherapy

Murdoch‐Kinch

Kim

Vineberg

et al. 2008

International Journal of Radiation Oncology*Biology*Physics

212

143

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Purpose-Submandibular salivary glands (SMGs) dysfunction contributes to xerostomia after radiotherapy (RT) of head and neck (HN) cancer. We assessed SMG dose-response relationships and their implications for sparing these glands by intensity modulated radiotherapy (IMRT).Patients and Methods-148 HN cancer patients underwent unstimulated and stimulated SMG salivary flow rate measurements selectively from Wharton's duct orifices, before RT and periodically through 24 months after RT. Correlations of flow rates and mean SMG doses were modeled throughout all time points. IMRT re-planning in eight patients whose contralateral level I was not a target incorporated the results in a new cost function aiming to spare contralateral SMGs.Results-Stimulated SMG flow rates decreased exponentially by (1.2%) Gy as mean doses increased up to 39 Gy threshold, and then plateaued near zero. At mean doses ≤39 Gy, but not higher, flow rates recovered over time at 2.2%/month. Similarly, the unstimulated salivary flow rates decreased exponentially by (3%) Gy as mean dose increased and recovered over time if mean dose was <39 Gy. IMRT re-planning reduced mean contralateral SMG dose by average 12 Gy, achieving ≤39 Gy in 5/8 patients, without target under-dosing, increasing the mean doses to the parotid glands and swallowing structures by average 2-3 Gy.Conclusions-SMG salivary flow rates depended on mean dose with recovery over time up to a threshold of 39 Gy. Substantial SMG dose reduction to below this threshold and without target under-dosing is feasible in some patients, at the expense of modestly higher doses to some other organs.

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“…Certain surgeons have developed SMG-transfer surgery to preserve the SMG and this procedure achieves good results (11,12), but the invasiveness limits its use in clinical practice. In the IMRT era, numerous studies identified the importance of SMG protection as it was observed that xerostomia could not be sufficiently reduced when the parotid gland was well preserved and the SMG was not (13)(14)(15)(16). In principle, determining the target volume for the level Ib lymph node is problematic.…”

Section: Introductionmentioning

confidence: 99%

A risk score model for the metastasis of level Ib lymph node based on the clinicopathological features of nasopharyngeal carcinoma in a large sample

Liu

et al. 2014

Molecular and Clinical Oncology

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Abstract. The aim of the present study was to develop a metastatic risk score model of neck level Ib lymph nodes in primary nasopharyngeal carcinoma (NPC) to guide the level Ib radiotherapy. There were a total of 1,557 patients enrolled in the study, and of these patients, 1,145 were included in the training set. Univariate χ 2 analysis and multivariate logistic regression analyses were used to screen the independent risk factors to construct the risk score model. A total of 85 patients in the validating set underwent a pathology biopsy of level Ib lymph nodes to test the model. The remaining 327 patients from the prognostic-research set were used to evaluate the prognostic impact of level Ib irradiation in high-and low-risk groups. The independent risk factors in the model were carotid sheath involvement, the maximal diameter of the neck lymph nodes (≥20 mm) and the involvement of the level II/III/IV lymph nodes. The involvement of level IV was assigned score 2 and the other risk factors were assigned score 1. According to the total scores, the patients were divided into the low-(total score, 0-1; level Ib metastasis rate, 0.5%) and high-risk groups (total score, 2-4; level Ib metastasis rate, 8.5%). In the validating set, the metastatic rate of level Ib in 43 low-risk patients was 0%, and the rate was 31.0% (13/42) in 42 high-risk patients. In the prognostic-research set, the prognosis of 137 low-risk patients was not affected by level Ib irradiation. However, level Ib unirradiation was an independent prognostic factor for the locoregional recurrence in 190 high-risk patients. According to the data, the novel score model could help assess the metastatic risk of level Ib in primary NPC, and the radiotherapy on level Ib may impact the locoregional recurrence in high-risk patients.

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Prospective Randomized Study of Intensity-Modulated Radiotherapy on Salivary Gland Function in Early-Stage Nasopharyngeal Carcinoma Patients

Abstract: IMRT is superior to 2DRT in preserving parotid function and results in less severe delayed xerostomia in the treatment of early-stage NPC. Incomplete improvement in patient's subjective xerostomia with parotid-sparing IMRT reflects the need to enhance protection of other salivary glands.

Cited by 662 publications

References 34 publications

Dosimetric Verification for Primary Focal Hypermetabolism of Nasopharyngeal Carcinoma Patients Treated with Dynamic Intensity-modulated Radiation Therapy

Dosimetric Verification for Primary Focal Hypermetabolism of Nasopharyngeal Carcinoma Patients Treated with Dynamic Intensity-modulated Radiation Therapy

Dose-Effect Relationships for the Submandibular Salivary Glands and Implications for Their Sparing by Intensity Modulated Radiotherapy

A risk score model for the metastasis of level Ib lymph node based on the clinicopathological features of nasopharyngeal carcinoma in a large sample

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