Skin Cancer of the Head and Neck With Perineural Invasion: Defining the Clinical Target Volumes Based on the Pattern of Failure
Received 11 March 2008; received in revised form 13 June 2008; accepted 15 June 2008. published online 20 October 2008.
Purpose
To analyze patterns of failure in patients with head-and-neck cutaneous squamous cell carcinoma (HNCSCC) and clinical/radiologic evidence of perineural invasion (CPNI), in order to define neural clinical target volume (CTV) for treatment planning.
Methods and Materials
Patients treated with three-dimensional (3D) conformal or intensity-modulated radiotherapy (IMRT) for HNCSCC with CPNI were included in the study. A retrospective review of the clinical charts, radiotherapy (RT) plans and radiologic studies has been conducted.
Results
Eleven consecutive patients with HNCSCCs with CPNI were treated from 2000 through 2007. Most patients underwent multiple surgical procedures and RT courses. The most prevalent failure pattern was along cranial nerves (CNs), and multiple CNs were ultimately involved in the majority of cases. In all cases the involved CNs at recurrence were the main nerves innervating the primary tumor sites, as well as their major communicating nerves. We have found several distinct patterns of disease spread along specific CNs depending on the skin regions harboring the primary tumors, including multiple branches of CN V and VII. These patterns and the pertinent anatomy are detailed in the this article.
Conclusions
Predictable disease spread patterns along cranial nerves supplying the primary tumor sites were found in this study. Awareness of these patterns, as well as knowledge of the relevant cranial nerve anatomy, should be the basis for CTV definition and delineation for RT treatment planning.
∗Department of Radiation Oncology, University of Michigan, Ann Arbor MI
†Department of Radiology, University of Michigan, Ann Arbor MI
‡Department of Head and Neck Surgery, University of Michigan, Ann Arbor MI
Reprint requests to: Avraham Eisbruch, M.D., Department of Radiation Oncology, University of Michigan, 1500 E Medical Center Drive, Ann Arbor MI 48109. Tel: (734) 936-9337; Fax: (734) 763-7370
Support for this work was provided by the Trico Foundation (to I.G.).
ABSTRACT