Cancer risks of dermatomyositis and polymyositis: a nationwide cohort study in Taiwan.
BACKGROUND
The association of idiopathic inflammatory myositis (IIM) and malignancies has been reported, but rarely in Asian countries. Our aim was to investigate the risk of cancer among IIM patients without a prior history of malignancies, in Taiwan.


METHODS
We conducted a nationwide cohort study of 1,012 patients with dermatomyositis (DM) and 643 patients with polymyositis (PM), but without prior history of malignancies, utilizing the National Health Insurance Database from 1997 to 2007. Standardized incidence ratios (SIRs) of cancers were analyzed.


RESULTS
A total of 95 cancers (9.4%) in DM and 33 cancers (4.4%) in PM were identified. Overall cancer risk was significantly elevated in DM patients (SIR = 5.11, 95% confidence interval [CI] = 5.01 to 5.22) and PM patients (SIR = 2.15, 95% CI = 2.08 to 2.22). Most cancers were detected in the first year of observation. The risk of cancer decreased with observation time, yet remained elevated compared with the general population in both study groups after 5 years of follow-up. DM was associated with sustained elevated risk of cancers in every age group, whereas the risk of cancer in PM was highest in younger patients and decreased with age. DM patients were at the greatest risk of cancers of the nasopharynx, lungs and hematopoietic malignancies.


CONCLUSIONS
Patients with IIM are at increased risk for cancer and should receive age-appropriate and gender-appropriate malignancy evaluations, with additional assessment for nasopharyngeal, lung and hematologic malignancy following diagnosis, and with continued vigilance for development of cancers in follow-up.
Chen
Yi-Ju
YJ
Department of Dermatology, National Yang-Ming University, No, 155, Sec, 2, Linong Street, Taipei 112, Taiwan.
Wu
Chun-Ying
CY
Huang
Yu-Lin
YL
Wang
Chang-Bi
CB
Shen
Jui-Lung
JL
Chang
Yun-Ting
YT
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D016208:Databases, Factual; D003882:Dermatomyositis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D017285:Polymyositis / Q000453:epidemiology*; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
J Neurol. 2005 May;252(5):519-25
15742118
Curr Rheumatol Rep. 2006 Jun;8(3):196-203
16901077
Arthritis Rheum. 1986 Jun;29(6):813-4
3718571
J Eur Acad Dermatol Venereol. 2008 Mar;22(3):399-401
18269627
Clin Exp Dermatol. 1994 Nov;19(6):523-5
7889681
Yonsei Med J. 2006 Aug 31;47(4):519-23
16941742
Cancer. 1981 Sep 1;48(5):1256-61
6791807
Arch Otolaryngol Head Neck Surg. 1995 Nov;121(11):1298-301
7576478
J Affect Disord. 2009 Mar;113(3):255-62
18640727
Int J Dermatol. 1985 Sep;24(7):447-50
4055199
Nihon Kyobu Shikkan Gakkai Zasshi. 1992 Oct;30(10):1858-63
1464989
N Engl J Med. 1992 Feb 6;326(6):363-7
1729618
N Engl J Med. 1975 Feb 20;292(8):403-7
1089199
Int J Urol. 2007 Oct;14(10):952-3
17880299
Clin Immunol Immunopathol. 1995 Dec;77(3):298-306
7586740
J Microbiol Immunol Infect. 2004 Jun;37(3):164-8
15221036
Zhonghua Yi Xue Za Zhi (Taipei). 1993 Nov;52(5):285-92
8299023
Gastroenterology. 2009 Nov;137(5):1641-8.e1-2
19664631
Br J Dermatol. 1995 Dec;133(6):1012
8547024
Arthritis Rheum. 2006 Nov;54(11):3682-9
17075819
Cancer Causes Control. 1995 Jan;6(1):9-13
7718740
N Engl J Med. 2004 Jun 10;350(24):2461-70
15190138
Rheumatol Int. 2008 Dec;29(2):203-5
18665364
Br J Cancer. 2001 Jul 6;85(1):41-5
11437400
Clin Cancer Res. 2000 Mar;6(3):1046-51
10741733
J Rheumatol. 1995 Jul;22(7):1300-3
7562762
J Exp Med. 2005 Feb 21;201(4):591-601
15728237
Ann Rheum Dis. 2007 Oct;66(10):1345-9
17392346
Br J Dermatol. 2001 Apr;144(4):825-31
11298544
Int J Urol. 2005 Oct;12(10):906-8
16323985
Ann Acad Med Singap. 2000 Mar;29(2):219-23
10895343
J Rheumatol. 1994 Oct;21(10):1855-9
7837150
Lancet. 2001 Jan 13;357(9250):96-100
11197446
Curr Opin Rheumatol. 2006 Nov;18(6):620-4
17053509
Curr Opin Rheumatol. 2009 Nov;21(6):594-8
19730376
Br J Dermatol. 2009 Oct;161(4):854-60
19558555
N Engl J Med. 1975 Feb 13;292(7):344-7
1090839
Rheumatology (Oxford). 2007 Jan;46(1):25-8
16728436
Rheumatol Int. 2009 Aug;29(10):1261-2
19142639
Acta Derm Venereol. 2009;89(3):262-6
19479122
Clin Gastroenterol Hepatol. 2009 Apr;7(4):427-31
19264578
J Reprod Med. 1988 Jul;33(7):649-55
3050072
J Vasc Interv Radiol. 2004 Jan;15(1 Pt 1):97-9
14709696
J Am Acad Dermatol. 2006 Feb;54(2):221-6
16443051
Am J Med Sci. 1997 Apr;313(4):249-51
9099158