title: The threshold of hypothyroidism after radiation therapy for head and neck cancer: a retrospective analysis of 116 cases.
abstract: The purpose of the present study was to determine the risk factors for developing thyroid disorders based on a dose-volume histograms (DVHs) analysis. Data from a total of 116 consecutive patients undergoing 3D conformal radiation therapy for head and neck cancers was retrospectively evaluated. Radiation therapy was performed between April 2007 and December 2010. There were 108 males and 8 females included in the study. The median follow-up term was 24 months (range, 1-62 months). The thyroid function was evaluated by measuring thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels. The mean thyroid dose, and the volume of thyroid gland spared from doses ≥10, 20, 30 and 40 Gy (VS10, VS20, VS30 and VS40) were calculated for all patients. The thyroid dose and volume were calculated by the radiotherapy planning system (RTPS). The cumulative incidences of hypothyroidism were 21.1% and 36.4% at one year and two years, respectively, after the end of radiation therapy. In the DVH analyses, the patients who received a mean thyroid dose <30 Gy had a significantly lower incidence of hypothyroidism. The univariate analyses showed that the VS10, VS20, VS30 and VS40 were associated with the risk of hypothyroidism. Hypothyroidism was a relatively common type of late radiation-induced toxicity. A mean thyroid dose of 30 Gy may be a useful threshold for predicting the development of hypothyroidism after radiation therapy for head and neck cancers.
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan Department of Radiation Oncology, Meiwa Cancer Clinic, Nishinomiya, Hyogo, Japan m-fuji@hyo-med.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Fujiwara
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Kamikonya
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan Department of Radiation Oncology, Meiwa Cancer Clinic, Nishinomiya, Hyogo, Japan.
authors.forename: Soichi
authors.initials: S
authors.lastname: Odawara
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Yasue
authors.initials: Y
authors.lastname: Niwa
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takada
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Doi
authors.affiliation: Department of Otolaryngology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Terada
authors.affiliation: Department of Otolaryngology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Uwa
authors.affiliation: Department of Otolaryngology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Sagawa
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors.forename: Shozo
authors.initials: S
authors.lastname: Hirota
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015984:Causality; D015897:Comorbidity; D005260:Female; D006258:Head and Neck Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D006801:Humans; D007037:Hypothyroidism / Q000175:diagnosis / Q000453:epidemiology*; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011832:Radiation Injuries / Q000175:diagnosis / Q000453:epidemiology*; D020266:Radiotherapy, Conformal / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D016896:Treatment Outcome
keywords: head and neck cancer; hypothyroidism; late radiation toxicity; radiation therapy
references.citation: Int J Radiat Oncol Biol Phys. 1995 Mar 30;31(5):1165-70
references.pmid: 7713780
references.citation: Laryngoscope. 1984 Apr;94(4):451-54
references.pmid: 6708688
references.citation: Best Pract Res Clin Endocrinol Metab. 2010 Feb;24(1):107-15
references.pmid: 20172475
references.citation: Am J Otolaryngol. 2007 Jan-Feb;28(1):46-9
references.pmid: 17162132
references.citation: J Biol Chem. 1948 Jun;174(2):555-64
references.pmid: 18865621
references.citation: J Surg Oncol. 1996 Apr;61(4):281-3
references.pmid: 8627999
references.citation: Arch Intern Med. 2009 Nov 23;169(21):2011-7
references.pmid: 19933964
references.citation: Int J Radiat Oncol Biol Phys. 2004 Oct 1;60(2):395-400
references.pmid: 15380571
references.citation: Int J Radiat Oncol Biol Phys. 2007 Jan 1;67(1):144-50
references.pmid: 17084554
references.citation: Int J Radiat Oncol Biol Phys. 2001 Nov 1;51(3):599-604
references.pmid: 11597798
references.citation: Int J Radiat Oncol Biol Phys. 2010 Jun 1;77(2):468-76
references.pmid: 19577867
references.citation: Arch Intern Med. 2000 Feb 28;160(4):526-34
references.pmid: 10695693
references.citation: J Clin Endocrinol Metab. 2002 Feb;87(2):489-99
references.pmid: 11836274
references.citation: Acta Otolaryngol. 2007 Mar;127(3):312-7
references.pmid: 17364370
references.citation: Am J Clin Oncol. 2009 Apr;32(2):150-3
references.pmid: 19307948
references.citation: Endocr Pract. 2012 Nov-Dec;18(6):988-1028
references.pmid: 23246686
references.citation: Jpn J Clin Oncol. 2014 Apr;44(4):331-7
references.pmid: 24482412
references.citation: Int J Radiat Oncol Biol Phys. 1991 May 15;21(1):109-22
references.pmid: 2032882
references.citation: Eur Arch Otorhinolaryngol. 2011 Oct;268(10):1519-22
references.pmid: 21328003
references.citation: Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1802-8
references.pmid: 21514076
references.citation: Nihon Igaku Hoshasen Gakkai Zasshi. 2004 Mar;64(3):146-50
references.pmid: 15148791
references.citation: Med Oncol. 2007;24(1):91-4
references.pmid: 17673817
references.citation: Radiother Oncol. 1992 Sep;25(1):31-6
references.pmid: 1410587
references.citation: Radiother Oncol. 2013 Nov;109(2):317-22
references.pmid: 23891099
references.citation: Radiother Oncol. 2000 Oct;57(1):97-101
references.pmid: 11033194