Effect of regression of enlarged neck lymph nodes on radiation doses received by parotid glands during intensity-modulated radiotherapy for head and neck cancer

Yu Cheng Kuo, Tung Ho Wu, Tao Sang Chung, Kuang Wei Huang, K. S Clifford Chao, Wen Chuan Su, Jeng Fong Chiou

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

OBJECTIVES: The regression of enlarged neck lymph nodes during intensity-modulated radiotherapy (IMRT) may increase actual radiation doses to the parotid glands of patients with head-and-neck cancer. We investigated the changes in the lymph nodes volume during IMRT and the effect of these changes to the parotid gland doses. METHODS: Ten head and neck cancer patients with enlarged neck lymph nodes were enrolled in this study. Computed tomography (CT) imaging was repeated to evaluate the change in lymph nodes volume after initial 45 Gy, and the second part of IMRT (21 Gy) was then replanned to reflect the change of nodal tumor volume. The dosimetric benefit of parotid sparing with replanning was compared with that of no replanning. RESULTS: The enlarged neck lymph nodes in all patients pushed the parotid glands outward in pretreatment CT images. After 45 Gy of IMRT, nodal regression caused the parotid glands to shift inward into the high-dose area. When compared with those without replanning, we found modification of IMRT plan after 45 Gy significantly reduced radiation dose to parotid glands (mean reduction of 2.95 ± 1.10 Gy to the left and 3.23 ± 1.37 Gy to the right, respectively; P <0.001). CONCLUSIONS: Excessive parotid gland doses secondary to the regression of enlarged neck nodes could be mitigated by replanning after 45 Gy. However, recontouring of large lymph nodes that regress during therapy has a risk of under-dosing extracapsular extension of lymph node metastases. Therefore, recontouring should be done with extreme caution.

Original languageEnglish
Pages (from-to)600-605
Number of pages6
JournalAmerican Journal of Clinical Oncology: Cancer Clinical Trials
Volume29
Issue number6
DOIs
Publication statusPublished - Dec 2006

Fingerprint

Intensity-Modulated Radiotherapy
Parotid Gland
Head and Neck Neoplasms
Neck
Lymph Nodes
Radiation
Tomography
Tumor Burden
Neoplasm Metastasis

Keywords

  • Enlarged neck lymph nodes
  • Head and neck cancers
  • IMRT
  • Parotid glands

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this

Effect of regression of enlarged neck lymph nodes on radiation doses received by parotid glands during intensity-modulated radiotherapy for head and neck cancer. / Kuo, Yu Cheng; Wu, Tung Ho; Chung, Tao Sang; Huang, Kuang Wei; Chao, K. S Clifford; Su, Wen Chuan; Chiou, Jeng Fong.

In: American Journal of Clinical Oncology: Cancer Clinical Trials, Vol. 29, No. 6, 12.2006, p. 600-605.

Research output: Contribution to journalArticle

@article{b430c63a60514c88b188dfbdf613f962,
title = "Effect of regression of enlarged neck lymph nodes on radiation doses received by parotid glands during intensity-modulated radiotherapy for head and neck cancer",
abstract = "OBJECTIVES: The regression of enlarged neck lymph nodes during intensity-modulated radiotherapy (IMRT) may increase actual radiation doses to the parotid glands of patients with head-and-neck cancer. We investigated the changes in the lymph nodes volume during IMRT and the effect of these changes to the parotid gland doses. METHODS: Ten head and neck cancer patients with enlarged neck lymph nodes were enrolled in this study. Computed tomography (CT) imaging was repeated to evaluate the change in lymph nodes volume after initial 45 Gy, and the second part of IMRT (21 Gy) was then replanned to reflect the change of nodal tumor volume. The dosimetric benefit of parotid sparing with replanning was compared with that of no replanning. RESULTS: The enlarged neck lymph nodes in all patients pushed the parotid glands outward in pretreatment CT images. After 45 Gy of IMRT, nodal regression caused the parotid glands to shift inward into the high-dose area. When compared with those without replanning, we found modification of IMRT plan after 45 Gy significantly reduced radiation dose to parotid glands (mean reduction of 2.95 ± 1.10 Gy to the left and 3.23 ± 1.37 Gy to the right, respectively; P <0.001). CONCLUSIONS: Excessive parotid gland doses secondary to the regression of enlarged neck nodes could be mitigated by replanning after 45 Gy. However, recontouring of large lymph nodes that regress during therapy has a risk of under-dosing extracapsular extension of lymph node metastases. Therefore, recontouring should be done with extreme caution.",
keywords = "Enlarged neck lymph nodes, Head and neck cancers, IMRT, Parotid glands",
author = "Kuo, {Yu Cheng} and Wu, {Tung Ho} and Chung, {Tao Sang} and Huang, {Kuang Wei} and Chao, {K. S Clifford} and Su, {Wen Chuan} and Chiou, {Jeng Fong}",
year = "2006",
month = "12",
doi = "10.1097/01.coc.0000239093.95769.b3",
language = "English",
volume = "29",
pages = "600--605",
journal = "American Journal of Clinical Oncology",
issn = "0277-3732",
publisher = "Lippincott Williams and Wilkins",
number = "6",

}

TY - JOUR

T1 - Effect of regression of enlarged neck lymph nodes on radiation doses received by parotid glands during intensity-modulated radiotherapy for head and neck cancer

AU - Kuo, Yu Cheng

AU - Wu, Tung Ho

AU - Chung, Tao Sang

AU - Huang, Kuang Wei

AU - Chao, K. S Clifford

AU - Su, Wen Chuan

AU - Chiou, Jeng Fong

PY - 2006/12

Y1 - 2006/12

N2 - OBJECTIVES: The regression of enlarged neck lymph nodes during intensity-modulated radiotherapy (IMRT) may increase actual radiation doses to the parotid glands of patients with head-and-neck cancer. We investigated the changes in the lymph nodes volume during IMRT and the effect of these changes to the parotid gland doses. METHODS: Ten head and neck cancer patients with enlarged neck lymph nodes were enrolled in this study. Computed tomography (CT) imaging was repeated to evaluate the change in lymph nodes volume after initial 45 Gy, and the second part of IMRT (21 Gy) was then replanned to reflect the change of nodal tumor volume. The dosimetric benefit of parotid sparing with replanning was compared with that of no replanning. RESULTS: The enlarged neck lymph nodes in all patients pushed the parotid glands outward in pretreatment CT images. After 45 Gy of IMRT, nodal regression caused the parotid glands to shift inward into the high-dose area. When compared with those without replanning, we found modification of IMRT plan after 45 Gy significantly reduced radiation dose to parotid glands (mean reduction of 2.95 ± 1.10 Gy to the left and 3.23 ± 1.37 Gy to the right, respectively; P <0.001). CONCLUSIONS: Excessive parotid gland doses secondary to the regression of enlarged neck nodes could be mitigated by replanning after 45 Gy. However, recontouring of large lymph nodes that regress during therapy has a risk of under-dosing extracapsular extension of lymph node metastases. Therefore, recontouring should be done with extreme caution.

AB - OBJECTIVES: The regression of enlarged neck lymph nodes during intensity-modulated radiotherapy (IMRT) may increase actual radiation doses to the parotid glands of patients with head-and-neck cancer. We investigated the changes in the lymph nodes volume during IMRT and the effect of these changes to the parotid gland doses. METHODS: Ten head and neck cancer patients with enlarged neck lymph nodes were enrolled in this study. Computed tomography (CT) imaging was repeated to evaluate the change in lymph nodes volume after initial 45 Gy, and the second part of IMRT (21 Gy) was then replanned to reflect the change of nodal tumor volume. The dosimetric benefit of parotid sparing with replanning was compared with that of no replanning. RESULTS: The enlarged neck lymph nodes in all patients pushed the parotid glands outward in pretreatment CT images. After 45 Gy of IMRT, nodal regression caused the parotid glands to shift inward into the high-dose area. When compared with those without replanning, we found modification of IMRT plan after 45 Gy significantly reduced radiation dose to parotid glands (mean reduction of 2.95 ± 1.10 Gy to the left and 3.23 ± 1.37 Gy to the right, respectively; P <0.001). CONCLUSIONS: Excessive parotid gland doses secondary to the regression of enlarged neck nodes could be mitigated by replanning after 45 Gy. However, recontouring of large lymph nodes that regress during therapy has a risk of under-dosing extracapsular extension of lymph node metastases. Therefore, recontouring should be done with extreme caution.

KW - Enlarged neck lymph nodes

KW - Head and neck cancers

KW - IMRT

KW - Parotid glands

UR - http://www.scopus.com/inward/record.url?scp=33845506430&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33845506430&partnerID=8YFLogxK

U2 - 10.1097/01.coc.0000239093.95769.b3

DO - 10.1097/01.coc.0000239093.95769.b3

M3 - Article

C2 - 17148998

AN - SCOPUS:33845506430

VL - 29

SP - 600

EP - 605

JO - American Journal of Clinical Oncology

JF - American Journal of Clinical Oncology

SN - 0277-3732

IS - 6

ER -