Individualization of Clinical Target Volume Delineation Based on Stepwise Spread of Nasopharyngeal Carcinoma: Outcome of More Than a Decade of Clinical Experience

Autor: Hsiao-Ming Lu, Annie W. Chan, Norbert J. Liebsch, Hugh D. Curtin, Nina N. Sanford, Jackson Lau, Amy F. Juliano, Miranda B. Lam, Judith Adams, Saveli Goldberg, Yue C. Lu
Rok vydání: 2018
Předmět:
Adult
Male
Cancer Research
medicine.medical_specialty
Adolescent
medicine.medical_treatment
Optic chiasm
Kaplan-Meier Estimate
030218 nuclear medicine & medical imaging
03 medical and health sciences
Young Adult
0302 clinical medicine
medicine
Proton Therapy
Humans
Radiology
Nuclear Medicine and imaging
Stage (cooking)
Neoplasm Metastasis
Radiation Injuries
Radiometry
Aged
Retrospective Studies
Contouring
Radiation
Models
Statistical
Nasopharyngeal Carcinoma
Radiotherapy
business.industry
Radiotherapy Planning
Computer-Assisted
Retrospective cohort study
Nasopharyngeal Neoplasms
Radiotherapy Dosage
Middle Aged
medicine.disease
Confidence interval
Radiation therapy
medicine.anatomical_structure
Treatment Outcome
Oncology
Nasopharyngeal carcinoma
Head and Neck Neoplasms
030220 oncology & carcinogenesis
Optic nerve
Female
Radiology
Radiotherapy
Intensity-Modulated
Neoplasm Recurrence
Local
business
Follow-Up Studies
Zdroj: International journal of radiation oncology, biology, physics. 103(3)
ISSN: 1879-355X
Popis: Purpose Radiation-related toxicity in nasopharyngeal carcinoma (NPC) is common. There are no well-established guidelines for clinical target volume (CTV) delineation with long-term follow-up. Current consensus continues to rely heavily on bony landmarks and fixed margins around the gross tumor volume (GTV), an approach used to define fields in the conventional 2- and 3-dimensional radiation therapy era. Methods and Materials We retrospectively evaluated patients with newly diagnosed nonmetastatic NPC treated with definitive radiation therapy using a technique of CTV delineation based on individual tumor extent and the orderly stepwise pattern of tumor spread. Dosimetric comparisons were made between national protocol HN001 and our contouring strategies on a representative early- and advanced-stage NPC. The primary endpoints were patterns of failure and local control; secondary endpoints included regional control and survival, estimated using the Kaplan-Meier method. Results Between 1999 and 2013, 73 patients (88% with stage 3-4 disease) were treated with median follow-up of 90 months for surviving patients. Median dose to GTV was 70 Gy. Four patients developed local recurrence and 1 patient developed regional recurrence. All locoregional recurrences occurred within the high-dose GTV. The 5-year local control, regional control, and overall survival was 94% (95% confidence interval [CI], 85%-98%), 99% (95% CI, 90%-100%), and 84% (95% CI, 73%-91%), respectively. Compared with HN001, our contouring strategy resulted in 62% and 36% reduction in CTV for T1 and T4 disease, respectively. In the T1 tumor, the reduction of doses to the contralateral parotid, optic nerve, and cochlea were 54%, 50%, 34% respectively. In the T4 case, there was a decrease of optic chiasm dose of 46% and contralateral optic nerve of 37%. There were 10 grade 3 toxicities. There was no grade 2 or higher xerostomia and no grade 4/5 toxicity. Conclusions Our long-term experience with individualized CTV delineation based on stepwise patterns of spread results in excellent local control, with no recurrence outside the GTV.
Databáze: OpenAIRE
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