發炎性肌炎病人罹癌的風險因子

Predicting factors of malignancy in infl ammatory myositis

目的：找出多發性肌炎（polymyositis, PM）與皮肌炎（dermatomyositis, DM）病人罹癌的風險因子。研究材料與方法：這個研究使用林口長庚醫院西元2000年到2007年中符合PM/DM的病人，進行病例回顧分析臨床及檢驗資料。結果：在151位符合PM/DM的病人中，有25位（16.6%）罹癌。鼻咽癌（41%）是所有皮肌炎病人最常見的惡性腫瘤。本研究的病患總體存活率：一年為81%，兩年為78%，五年為75%。單變數迴歸分析顯示：發病年齡較晚、shawl sign、heliotrope rash、皮膚癢、合併糖尿病、低肌酸磷酸激酶（creatine phophokinase, CPK）以及天門冬胺酸轉胺基酶值（aspartate aminotransferase, AST）在PM/DM罹癌組較高。多變數迴歸分析顯示：發病年齡大於45歲（OR = 5.52, 95% CI = 1.23-24.76, p=0.026）以及heliotrope rash（OR = 7.37, 95% CI = 1.55-34.97, p=0.012）是兩個PM/DM病患罹癌的獨立風險因子。結論：在PM/DM罹癌組的存活率明顯較低。發病年齡大於45歲以及heliotrope rash是兩個PM/DM病患罹癌的獨立風險因子，有這兩種風險因子的PM/DM病患應考慮做詳細的癌症篩檢。

Objective: To identify the potential risk factors of neoplastic diseases in patients with polymyositis (PM) and dermatomyositis (DM). Methods: The medical records of 151 PM/DM patients followed up in a tertiary teaching medical center between January 2000 and June 2007 were retrospectively reviewed. Results: Among the 151 patients, 25 patients (16.6%) had associated cancer and most of these cases were associated with DM. Nasopharyngeal carcinoma (41%) comprised the most common malignant disease associated with DM. Overall patient survival rates were 81% at 1 year, 78% at 2 years, and 75% at 5 years. Univariate analysis showed that an older age at PM/DM onset, heliotrope rash, shawl sign, pruritus, diabetes mellitus, low creatine phosphokinase (CPK) level and low aspartate aminotransferase (AST) level were associated with increase malignancy. Multivariate analysis revealed that independent predictors of malignancy in PM/DM were age of >45 years at PM/DM onset (OR = 5.52; 95% CI = 1.23-24.76; p=0.026) and heliotrope rash (OR = 7.37; 95% CI = 1.55-34.97; p=0.012). Conclusions: PM/DM patients with underling malignancy were signifi cantly associated with decreased survival. Our results indicate that the 2 independent predicting factors for malignancy in patients with DM/PM are an older age at onset (>45 years) and heliotrope rash (p<0.005). Patients with these risk factors should be screened for malignancy.