TY - JOUR
T1 - Individualization of Clinical Target Volume Delineation Based on Stepwise Spread of Nasopharyngeal Carcinoma
T2 - Outcome of More Than a Decade of Clinical Experience
AU - Sanford, Nina N.
AU - Lau, Jackson
AU - Lam, Miranda B.
AU - Juliano, Amy F.
AU - Adams, Judith A.
AU - Goldberg, Saveli I.
AU - Lu, Hsiao Ming
AU - Lu, Yue C.
AU - Liebsch, Norbert J.
AU - Curtin, Hugh D.
AU - Chan, Annie W.
N1 - Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2019/3/1
Y1 - 2019/3/1
N2 - 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.
AB - 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.
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U2 - 10.1016/j.ijrobp.2018.10.006
DO - 10.1016/j.ijrobp.2018.10.006
M3 - Article
C2 - 30712708
AN - SCOPUS:85060484012
SN - 0360-3016
VL - 103
SP - 654
EP - 668
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 3
ER -