Cancer Res Treat.  2019 Apr;51(2):603-610. 10.4143/crt.2018.240.

Feasibility of Selective Neck Irradiation with Lower Elective Radiation Dose in Treating Nasopharynx Cancer Patients

• Cho WK
• Oh D
• Lee E
• Kim TG
• Lee H
• Nam H
• Noh JM
• Ahn YC

• KMID: 2464407
• DOI: http://doi.org/10.4143/crt.2018.240

Abstract

PURPOSE
This study aimed to report the clinical outcomes following selective neck irradiation (SNI) with lower elective radiation therapy (RT) dose in treating nasopharyngeal cancer (NPC) patients.
MATERIALS AND METHODS
A total of 347 NPC patients received definitive RT according to our SNI policy and were retrospectively analyzed. The clinical target volumes (CTVs) were subdivided into CTV at high risk (CTV-HR) and CTV at low risk (CTV-LR). The typical doses to gross tumor volume (GTV), CTV-HR, and CTV-LR were 68.4-70.0 Gy, 54.0-60.0 Gy, and 36.0 Gy.
RESULTS
With the median follow-up of 68.1 months (range, 2.3 to 197.1 months), the 5-year rates of loco-regional control and progression-free survival in all the patients were 85.0% and 70.8%, respectively. Thirty patients developed regional failure and the regional control rates at 3 and 5 years were 92.6% and 91.4%, respectively. The sites of regional failure in relation to the target volume were exclusively inside GTV/CTV-HR in 20, inside and outside GTV/CTVHR in three, and exclusively outside GTV/CTV-HR in seven, which were 5.7%, 0.9%, and 2.0% of total patients, respectively.
CONCLUSION
The clinical outcomes by the current SNI policy were feasible and comparable to those following classic elective nodal irradiation policy.

Keyword

Nasopharyngeal carcinoma; Lymphatic irradiation; Radiotherapy

MeSH Terms

Disease-Free Survival
Follow-Up Studies
Humans
Lymphatic Irradiation
Nasopharyngeal Neoplasms*
Nasopharynx*
Neck*
Radiotherapy
Retrospective Studies
Tumor Burden

Figure

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  Fig. 1. The policy of selective neck irradiation with differential radiation dose plan employed in the current study is illustrated: (A) 66-72 Gy to gross tumor volume (GTV) of primary tumor and metastatic lymph nodes; (B) 54-60 Gy to clinical target volume at high risk (CTV-HR) that included 1.0-1.5 cm margin to nodal GTV; and (C) 36 Gy to clinical target volume at low risk (CTV-LR) that included 2-2.5 cm distal margin from CTV-HR.

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  Fig. 2. Patterns of failure in 100 patients.

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  Fig. 3. The sites of regional failures in relation to target volume and detail of seven patients who developed regional failure in or outside clinical target volume at low risk (CTV-LR). GTV, gross tumor volume; CTV-HR, clinical target volume at high risk. RT, radiotherapy; NED, no evidence of disease; DOD, dead of disease; M, male.

Reference

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