Waleed F Mourad1, Brett M Young2, Rebekah Young3, Dukagjin M Blakaj3, Nitin Ohri3, Rania A Shourbaji4, Spiros Manolidis5, Mauricio Gámez4, Mahesh Kumar4, Azita Khorsandi6, Majid A Khan7, Daniel Shasha4, Adriana Blakaj3, Jonathan Glanzman3, Madhur K Garg3, Kenneth S Hu4, Shalom Kalnicki3, Louis B Harrison4. 1. Department of Radiation Oncology, Beth Israel Medical Center, New York, NY, United States; Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, New York, NY, United States. Electronic address: Waleed246@gmail.com. 2. Department of Neuroradiology, Duke University Medical Center, Durham, NC, United States. 3. Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, New York, NY, United States. 4. Department of Radiation Oncology, Beth Israel Medical Center, New York, NY, United States. 5. Department of Otolaryngology, Beth Israel Medical Center, New York, NY, United States. 6. Department of Neuroradiology, Beth Israel Medical Center, New York, NY, United States. 7. Department of Neuroradiology, University of Mississippi Medical Center, Jackson, MS, United States.
Abstract
OBJECTIVES: Radiation induced cranial nerve palsy (RICNP) involving the lower cranial nerves (CNs) is a serious complication of head and neck radiotherapy (RT). Recommendations for delineating the lower CNs on RT planning studies do not exist. The aim of the current study is to develop a standardized methodology for contouring CNs IX-XII, which would help in establishing RT limiting doses for organs at risk (OAR). METHODS: Using anatomic texts, radiologic data, and guidance from experts in head and neck anatomy, we developed step-by-step instructions for delineating CNs IX-XII on computed tomography (CT) imaging. These structures were then contoured on five consecutive patients who underwent definitive RT for locally-advanced head and neck cancer (LAHNC). RT doses delivered to the lower CNs were calculated. RESULTS: We successfully developed a contouring atlas for CNs IX-XII. The median total dose to the planning target volume (PTV) was 70Gy (range: 66-70Gy). The median CN (IX-XI) and (XII) volumes were 10c.c (range: 8-12c.c) and 8c.c (range: 7-10c.c), respectively. The median V50, V60, V66, and V70 of the CN (IX-XI) and (XII) volumes were (85, 77, 71, 65) and (88, 80, 74, 64) respectively. The median maximal dose to the CN (IX-XI) and (XII) were 72Gy (range: 66-77) and 71Gy (range: 64-78), respectively. CONCLUSIONS: We have generated simple instructions for delineating the lower CNs on RT planning imaging. Further analyses to explore the relationship between lower CN dosing and the risk of RICNP are recommended in order to establish limiting doses for these OARs. Published by Elsevier Ltd.
OBJECTIVES: Radiation induced cranial nerve palsy (RICNP) involving the lower cranial nerves (CNs) is a serious complication of head and neck radiotherapy (RT). Recommendations for delineating the lower CNs on RT planning studies do not exist. The aim of the current study is to develop a standardized methodology for contouring CNs IX-XII, which would help in establishing RT limiting doses for organs at risk (OAR). METHODS: Using anatomic texts, radiologic data, and guidance from experts in head and neck anatomy, we developed step-by-step instructions for delineating CNs IX-XII on computed tomography (CT) imaging. These structures were then contoured on five consecutive patients who underwent definitive RT for locally-advanced head and neck cancer (LAHNC). RT doses delivered to the lower CNs were calculated. RESULTS: We successfully developed a contouring atlas for CNs IX-XII. The median total dose to the planning target volume (PTV) was 70Gy (range: 66-70Gy). The median CN (IX-XI) and (XII) volumes were 10c.c (range: 8-12c.c) and 8c.c (range: 7-10c.c), respectively. The median V50, V60, V66, and V70 of the CN (IX-XI) and (XII) volumes were (85, 77, 71, 65) and (88, 80, 74, 64) respectively. The median maximal dose to the CN (IX-XI) and (XII) were 72Gy (range: 66-77) and 71Gy (range: 64-78), respectively. CONCLUSIONS: We have generated simple instructions for delineating the lower CNs on RT planning imaging. Further analyses to explore the relationship between lower CN dosing and the risk of RICNP are recommended in order to establish limiting doses for these OARs. Published by Elsevier Ltd.
Entities:
Keywords:
Base of skull, nasopharyngeal and Paranasalsinus cancer; Contouring atlas; Intensity-modulated radiotherapy (IMRT); Locally Advanced Head-and-neck cancer (LAHNC); Lower cranial nerves IX–XII palsy; Radiotherapy (RT)
Authors: Stefan Janssen; Christoph Glanzmann; Bita Yousefi; Karl Loewenich; Gerhard Huber; Stephan Schmid; Gabriela Studer Journal: Mol Clin Oncol Date: 2015-05-04