Hypothyroidism as a consequence of intensity-modulated radiotherapy with concurrent taxane-based chemotherapy for locally advanced head-and-neck cancer.

Abstract

PURPOSE:

To conduct a retrospective review of 168 consecutively treated locally advanced head-and-neck cancer (LAHNC) patients treated with intensity-modulated radiotherapy (IMRT)/chemotherapy, to determine the rate and risk factors for developing hypothyroidism.

METHODS AND MATERIALS:

Intensity-modulated radiotherapy was delivered in 33 daily fractions to 69.3 Gy to gross disease and 56.1 Gy to clinically normal cervical nodes. Dose-volume histograms (DVHs) of IMRT plans were used to determine radiation dose to thyroid and were compared with DVHs using conventional three-dimensional radiotherapy (3D-RT) in 10 of these same patients randomly selected for replanning and with DVHs of 16 patients in whom the thyroid was intentionally avoided during IMRT. Weekly paclitaxel (30 mg/m(2)) and carboplatin area under the curve-1 were given concurrently with IMRT.

RESULTS:

Sixty-one of 128 evaluable patients (47.7%) developed hypothyroidism after a median of 1.08 years after IMRT (range, 2.4 months to 3.9 years). Age and volume of irradiated thyroid were associated with hypothyroidism development after IMRT. Compared with 3D-RT, IMRT with no thyroid dose constraints resulted in significantly higher minimum, maximum, and median dose (p < 0.0001) and percentage thyroid volume receiving 10, 20, and 60 Gy (p < 0.05). Compared with 3D-RT, IMRT with thyroid dose constraints resulted in lower median dose and percentage thyroid volume receiving 30, 40, and 50 Gy (p < 0.005) but higher minimum and maximum dose (p < 0.005).

CONCLUSIONS:

If not protected, IMRT for LAHNC can result in higher radiation to the thyroid than with conventional 3D-RT. Techniques to reduce dose and volume of radiation to thyroid tissue with IMRT are achievable and recommended.

• Authors: Roberto Diaz, Jerry J Jaboin, Manuel Morales-Paliza, Elizabeth Koehler, John G Phillips, Scott Stinson, Jill Gilbert, Christine H Chung, Barbara A Murphy, Wendell G Yarbrough, Patrick B Murphy, Yu Shyr, Anthony J Cmelak
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 77 Issue 2 Pg. 468-76 (Jun 01 2010) ISSN: 1879-355X [Electronic] United States
• PMID: 19577867 (Publication Type: Journal Article)
• Copyright: Copyright 2010 Elsevier Inc. All rights reserved.

Chemical References

• Bridged-Ring Compounds
• Taxoids
• taxane
• Carboplatin
• Paclitaxel

Topics

• Age Factors
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Bridged-Ring Compounds (administration & dosage)
• Carboplatin (administration & dosage)
• Combined Modality Therapy (adverse effects, methods)
• Dose Fractionation, Radiation
• Female
• Head and Neck Neoplasms (diagnostic imaging, drug therapy, pathology, radiotherapy)
• Humans
• Hypothyroidism (etiology)
• Male
• Middle Aged
• Paclitaxel (administration & dosage)
• Radiation Injuries (prevention & control)
• Radiography
• Radiotherapy, Intensity-Modulated (adverse effects)
• Retrospective Studies
• Risk Factors
• Taxoids (administration & dosage)
• Thyroid Gland (anatomy & histology, drug effects, radiation effects)