1. A Prospective 10-Year Observational Study of Reduction of Radiation Therapy Clinical Target Volume and Dose in Early-Stage Nasopharyngeal Carcinoma
- Author
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Fei Han, Kah Hie Wong, Wei-Xiong Xia, Jingjing Miao, Xiang Guo, Yan-Qing Cao, Yan-Qun Xiang, Joseph Wee, Huageng Huang, Weiwei Xiao, Melvin L.K. Chua, Chong Zhao, Boyu Chen, Shaomin Huang, Xiaowu Deng, Muping Di, Luo Huang, Xing Lv, Lin Wang, Manyi Zhu, and Sze Huey Tan
- Subjects
Adult ,Male ,Cancer Research ,medicine.medical_specialty ,medicine.medical_treatment ,Radiation Dosage ,Trismus ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Temporal lobe necrosis ,0302 clinical medicine ,medicine ,Clinical endpoint ,Humans ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,Stage (cooking) ,Subcutaneous fibrosis ,Neoplasm Staging ,Radiation ,business.industry ,Cancer ,Nasopharyngeal Neoplasms ,Radiotherapy Dosage ,Middle Aged ,medicine.disease ,Radiation therapy ,Oncology ,Nasopharyngeal carcinoma ,030220 oncology & carcinogenesis ,Female ,Radiology ,medicine.symptom ,business - Abstract
Purpose Current guideline recommends a uniform method of delineation of subclinical disease within the primary clinical target volume (CTVp) for all stages of nasopharyngeal carcinoma (NPC). We performed a prospective observational study to investigate the outcomes with a reduced CTVp and radiation dose for early-stage NPC. Methods and Materials Patients with newly diagnosed, biopsy-proven World Health Organization type II-III and American Joint Committee on Cancer/Union for International Cancer Control sixth edition stage T1-2N0-1 disease were enrolled. All patients were treated with intensity modulated radiation therapy alone. We categorized CTVp into CTVp1 (high risk) and CTVp2 (low risk). CTVp1 comprised of gross tumor (on magnetic resonance imaging or contrast-enhanced computed tomography) plus a 5-mm margin (3-mm posteriorly) and was prescribed to 60 Gy in 30 fractions (fr). CTVp2 was generated from CTVp1 plus a 5-mm margin (3 mm posteriorly), excluding the maxillary and cavernous sinuses, and was prescribed to 54 Gy in 30 fr. The prescribed doses to the primary and nodal gross tumor volume (GTVp and GTVn) were 68 Gy in 30 fr and 60 to 66 Gy in 30 fr, respectively. Primary endpoint was local recurrence-free survival. This study was registered in ClinicalTrials.gov , number NCT03839602 . Results From May 2001 to August 2006, 103 patients were recruited and completed IMRT. With a median follow-up of 15.2 years (range, 2.1-18.1 years), only 1 patient had local failure. Ten-year local recurrence-free survival, regional recurrence-free survival, distant metastasis-free survival, and overall survival were 90.3%, 88.3%, 90.3%, and 91.2%, respectively. Among late IMRT-related adverse events, we recorded 2 patients with G1 cranial nerve injury, 3 patients with G3 hearing loss, and 3 patients with G3 subcutaneous fibrosis. No patients had temporal lobe necrosis, brain stem injury, or trismus. Conclusions Decreased CTV margins and radiation doses can achieve long-term tumor control with mild late toxicities for patients with early-stage NPC.
- Published
- 2020
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