Dataset Information

The Impact of Clinical Stage on Radiation Doses to Organs at Risk Following Intensity-modulated Radiotherapy in Nasopharyngeal Carcinoma: A Prospective Analysis.

ABSTRACT: Background: The development of intensity-modulated radiotherapy (IMRT) has revolutionized the management of nasopharyngeal carcinoma (NPC). The purpose of this study was to investigate the impact of clinical stage on radiation doses to organs at risk (OARs) in NPC. Material and Methods: One hundred and forty-eight patients with newly diagnosed and untreated NPC were prospectively enrolled. Based on the anatomic definition and pathogenesis of radiation induced injury, a total of 28 OARs surrounding the nasopharynx were contoured on axial computed tomography (CT) planning images in each patient. Dose-volume histograms, as well as the mean and maximal doses for each structure, were calculated. Results: Radiation doses to 15 OARs (including the brain stem, temporal lobe and eye) were positively correlated with T stage, the radiation doses to 13 OARs (including the brachial plexus, parotid and thyroid) increased significantly with N stage, and the radiation doses to the spinal cord and mandible had no association with T or N stage. Based on the characteristic of excess rates, 9 OARs (e.g. spinal cord, eye, trachea, and et al.) met tolerance doses easily in all stages, 9 OARs (e.g. brain stem, temporal lobe, brachial plexus, and et al.) easily in early stages but with difficulty in advanced stages, and 10 OARs (e.g. cochlea, parotid, thyroid, and et al.) with difficulty in all stages. Conclusions: The radiation doses to most of OARs are associated with T or N stage, and there are three kinds of patterns for them: 1) meet tolerance doses easily in all stages; 2) meet tolerance doses easily in early stages but with difficulty in advanced stages; and 3) meet tolerance doses with difficulty in all stages.

SUBMITTER: Xu L

PROVIDER: S-EPMC5118681 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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The Impact of Clinical Stage on Radiation Doses to Organs at Risk Following Intensity-modulated Radiotherapy in Nasopharyngeal Carcinoma: A Prospective Analysis.

Xu Lin L Yao Ji-Jin JJ Zhou Guan-Qun GQ Zhang Wang-Jian WJ Liu Guo-Long GL Liu Li-Zhi LZ Ma Jun J Sun Ying Y

Journal of Cancer 20161025 14

<b>Background:</b> The development of intensity-modulated radiotherapy (IMRT) has revolutionized the management of nasopharyngeal carcinoma (NPC). The purpose of this study was to investigate the impact of clinical stage on radiation doses to organs at risk (OARs) in NPC. <b>Material and Methods:</b> One hundred and forty-eight patients with newly diagnosed and untreated NPC were prospectively enrolled. Based on the anatomic definition and pathogenesis of radiation induced injury, a total of 28 ...[more]

PMID: 27877233

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Project description:BACKGROUND:The National Comprehensive Cancer Network guidelines recommend intensity-modulated radiotherapy (IMRT) as the primary curative treatment for newly diagnosed nasopharyngeal carcinoma (NPC), but the radiation-related complications and relatively high medical costs remain a consequential burden for the patients. Endoscopic nasopharyngectomy (ENPG) was successfully applied in recurrent NPC with radiation free and relatively low medical costs. In this study, we examined whether ENPG could be an effective treatment for localized stage I NPC. METHODS:Ten newly diagnosed localized stage I NPC patients voluntarily received ENPG alone from June 2007 to September 2017 in Sun Yat-sen University Cancer Center. Simultaneously, the data of 329 stage I NPC patients treated with IMRT were collected and used as a reference cohort. The survival outcomes, quality of life (QOL), and medical costs between two groups were compared. RESULTS:After a median follow-up of 59.0 months (95% CI 53.4-64.6), no death, locoregional recurrence, or distant metastasis was observed in the 10 patients treated with ENPG. The 5-year overall survival, local relapse-free survival, regional relapse-free survival, and distant metastasis-free survival among the ENPG-treated patients was similar to that among the IMRT-treated patients (100% vs. 99.1%, 100% vs. 97.7%, 100% vs. 99.0%, 100% vs. 97.4%, respectively, P?>?0.05). In addition, compared with IMRT, ENPG was associated with decreased total medical costs ($ 4090.42?±?1502.65 vs. $ 12620.88?±?4242.65, P?<?0.001) and improved QOL scores including dry mouth (3.3?±?10.5 vs. 34.4?±?25.8, P?<?0.001) and sticky saliva (3.3?±?10.5 vs. 32.6?±?23.3, P?<?0.001). CONCLUSIONS:ENPG alone was associated with promising long-term survival outcomes, low medical costs, and satisfactory QOL and might therefore be an alternative strategy for treating newly diagnosed localized stage I NPC patients who refused radiotherapy. However, the application of ENPG should be prudent, and prospective clinical trials were needed to further verify the results.

Project description:BackgroundTo investigate the feasibility of a knowledge-based automated intensity-modulated radiation therapy (IMRT) planning technique for locally advanced nasopharyngeal carcinoma (NPC) radiotherapy.MethodsOne hundred forty NPC patients treated with definitive radiation therapy with the step-and-shoot IMRT techniques were retrospectively selected and separated into a knowledge library (n = 115) and a test library (n = 25). For each patient in the knowledge library, the overlap volume histogram (OVH), target volume histogram (TVH) and dose objectives were extracted from the manually generated plan. 5-fold cross validation was performed to divide the patients in the knowledge library into 5 groups before validating one group by using the other 4 groups to train each neural network (NN) machine learning models. For patients in the test library, their OVH and TVH were then used by the trained models to predict a corresponding set of mean dose objectives, which were subsequently used to generate automated plans (APs) in Pinnacle planning system via an in-house developed automated scripting system. All APs were obtained after a single step of optimization. Manual plans (MPs) for the test patients were generated by an experienced medical physicist strictly following the established clinical protocols. The qualities of the APs and MPs were evaluated by an attending radiation oncologist. The dosimetric parameters for planning target volume (PTV) coverage and the organs-at-risk (OAR) sparing were also quantitatively measured and compared using Mann-Whitney U test and Bonferroni correction.ResultsAPs and MPs had the same rating for more than 80% of the patients (19 out of 25) in the test group. Both AP and MP achieved PTV coverage criteria for no less than 80% of the patients. For each OAR, the number of APs achieving its criterion was similar to that in the MPs. The AP approach improved planning efficiency by greatly reducing the planning duration to about 17% of the MP (9.85 ± 1.13 min vs. 57.10 ± 6.35 min).ConclusionA robust and effective knowledge-based IMRT treatment planning technique for locally advanced NPC is developed. Patient specific dose objectives can be predicted by trained NN models based on the individual's OVH and clinical TVH goals. The automated planning scripts can use these dose objectives to efficiently generate APs with largely shortened planning time. These APs had comparable dosimetric qualities when compared to our clinic's manual plans.

Dataset Information

The Impact of Clinical Stage on Radiation Doses to Organs at Risk Following Intensity-modulated Radiotherapy in Nasopharyngeal Carcinoma: A Prospective Analysis.

Publications

The Impact of Clinical Stage on Radiation Doses to Organs at Risk Following Intensity-modulated Radiotherapy in Nasopharyngeal Carcinoma: A Prospective Analysis.

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