Evaluating the Rationality of the International Guideline About Selective Coverage of Level Ib in CTV With NPC

Study Overview
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Brief Summary
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The purpose of this study was to evaluate its rationality in real-world data and provide clinical evidence for the refinement of nodal CTV delineation in nasopharyngeal carcinoma(NPC).

Detailed Description
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Intensity-modulated radiation therapy (IMRT) has gradually replaced two-dimensional radiation therapy as it offers improved target conformity. Xerostomia is still the most common side effect of radiotherapy in patients with NPC treated with IMRT. Most stimulated saliva is secreted by the parotid glands (PGs), while the submandibular glands (SMGs) produce most of the unstimulated saliva and mucins, which may influence the degree of a dry mouth sensation.There are still differences in the understanding of nasopharyngeal cancer experts at home and abroad on the delineation of clinical target volumes., suitable criteria for elective irradiation of neck level Ib need to be re-evaluated.Therefore, we conducted a retrospective study to assess the feasibility of recommendation to level Ib in the International Guideline for Delineation of Clinical Target Volumes.

Official Title
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Evaluating the Rationality of the International Guideline's Recommendations Regarding Selective Coverage of Level Ib in Node Clinical Target Volume With Nasopharyngeal Carcinoma : Results From a Real-world Series

Conditions
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Nasopharyngeal Carcinoma

Intervention / Treatment
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* Radiation: IB-positive group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: histologically confirmed NPC by biopsy (clearly recorded in the pathology report or medical history) ; no evidence of distant metastasis at initial diagnosis and receiving radical IMRT in our center the following conditions: ① level IB metastasis, ② involvement of the submandibular gland, ③ involvement of structures that drain to level Ib as the first echelon site ( the oral cavity, anterior half of nasal cavity involvement) ④ involvement of level II LNs with extracapsular extension（because the judgment of extracapsular invasion is greatly influenced by subjective factors, this study only include patients who had high grade ENE(G2/G3 as demonstrated in our previous study: Oral Oncol. 2019 Dec;99:104438.)⑤ level II nodal involvement with maximum nodal axial diameter greater than 2 cm. all patients who were treated at Lin Shaojun's attending group from June 2005 to December 2012. presence of complete baseline magnetic resonance imaging data of the nasopharyngeal skull base and neck and treated in our center at initial diagnosis . Exclusion Criteria: disease progression during IMRT; fail to obtain tumor efficacy evaluation information in the medical records of the research center; previous malignancy or other concomitant malignant disease; receiving blind treatment in clinical research.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| IB-positive group<br>Patients with level IB metastasis and histologically confirmed positive by biopsy. | Radiation: IB-positive group<br>* The gross tumor volume of the nasopharynx and neck nodes (GTVnx and GTVnd) were delineated according to the tumor extension. The CTVnx was defined as GTVnx + nasopharynx mucosa + 8mm +corresponding anatomical structure without the delineation of CTV1. The CTVnd was defined as GTVnd plus the elective neck area. The prescribe doses of GTVnx/GTVnd, CTVnx, CTVnd were 66-70Gy,54-56Gy and 50-54Gy in 31-35 fractions, respectively.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| regional recurrence-free survival (RRFS) | The duration of time to regional failure were calculated from the start of treatment to the dates of recurrence. | 60 months | 
| level IB nodal recurrence-free survival | The duration of time to level Ib recurrence were calculated from the start of treatment to the date of Ievel Ib recurrence. | 60 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| local recurrence-free survival (LRFS) | LRFS was calculated from the start of treatment to the dates of local recurrence. | 60 months | 
| distant metastasis-free survival (DMFS) | DMFS was calculated from the start of treatment to the dates of distant metastasis. | 60 months | 
| Overall survival | OS was calculated from the date of randomization to death from any cause. | 60 months |