Location of cervical lymph node metastases in oropharyngeal and hypopharyngeal carcinoma: implications for cranial border of elective nodal target volumes.
OBJECTIVE
To analyze the exact location of the most cranial metastatic cervical lymph node in patients with oropharyngeal or hypopharyngeal carcinoma. This was done to specify the cranial border of the elective nodal target volume for improvement of parotid-sparing irradiation.


METHODS
The most cranial metastatic lymph node, ipsilateral and, when present, contralateral, was delineated on 58 diagnostic CT scans of patients with node-positive oropharyngeal or hypopharyngeal carcinoma. The distances from the delineated lymph node to the base of the skull were measured in all planes.


RESULTS
The mean ipsilateral and contralateral distance to the base of the skull in the coronal plane was 25.6 mm (range 2.6-73.8; SD 14.7) and 34.7 mm (range 10.4-78.9; SD 14.0), respectively (p = 0.002). Ipsilateral and contralateral metastatic lymph nodes were located within 20 mm below the base of the skull in 24 patients (41%) and 3 patients (5%), respectively.


CONCLUSIONS
Contralateral metastatic lymph nodes are more caudally located than are ipsilateral metastatic lymph nodes. In elective irradiation, lowering the cranial border of the contralateral nodal target volume with 20 mm below the base of the skull should be considered.
Prins-Braam
Pètra M
PM
Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands. p.braam@radcl.ruu.nl
Raaijmakers
Cornelis P J
CP
Terhaard
Chris H J
CH
D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000532:radiotherapy / Q000556:secondary*; D005260:Female; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D021621:Imaging, Three-Dimensional; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging / Q000532:radiotherapy; D008297:Male; D009333:Neck; D009367:Neoplasm Staging; D009959:Oropharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D010306:Parotid Gland / Q000000981:diagnostic imaging; D019291:Skull Base; D014057:Tomography, X-Ray Computed