Objective This study aims to evaluate the diagnostic accuracy of CA-125 and PET/CT in detecting cancer among adult patients with idiopathic inflammatory myopathy (IIM). Methods We conducted a retrospective study of a single-centre cohort of adult IIM patients enrolled from 2003 to 2020. Data on CA-125 and PET/CT tests conducted within five years of IIM symptom onset were extracted from electronic medical records. The outcomes assessed included true-positive, false-positive, true-negative and false-negative results. Results Among 1432 patients with IIM, 250 CA-125 tests were conducted on 205 patients within the first five years of symptom onset, yielding a false-positive rate of 3.1% and a false-negative rate of 14.3%. Most false-positives were associated with endometriosis or uterine fibroids, but additional medical procedures were often carried out to investigate the false-positive results. For PET/CT, 149 tests were performed on 139 patients, resulting in a false-positive rate of 5.5% and a false-negative rate of 28.6%. Lymphadenopathy and lung nodules were the predominant causes of false-positives, while melanoma, low-stage breast cancer and prostate cancer were the most frequent cancers missed (false-negatives). Conclusion False-positive and false-negative results are prevalent in cancer antigen 125 (CA-125) and PET/CT testing for adult patients with newly diagnosed idiopathic inflammatory myopathy. Understanding the causes of these inaccuracies can aid clinicians in making informed decisions during patient care.

中文翻译：

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评估 CA-125 和 PET/CT 在特发性炎症性肌病中癌症检测的作用


目的 评价 CA-125 和 PET/CT 在特发性炎症性肌病 （IIM） 成人患者中检测癌症的诊断准确性。方法 我们对 2003 年至 2020 年入组的成年 IIM 患者的单中心队列进行了回顾性研究。从 IMM 症状出现后 5 年内进行的 CA-125 和 PET/CT 检测数据提取自电子病历。评估的结局包括真-阳性、假阳性、真-阴性和假-阴性结果。结果 在 1432 例 IIM 患者中，对 205 例患者在症状发作的前 5 年内进行了 250 次 CA-125 检测，假阳性率为 3.1%，假阴性率为 14.3%。大多数假阳性与子宫内膜异位症或子宫肌瘤有关，但通常会进行额外的医疗程序来调查假阳性结果。PET/CT 对 139 例患者进行了 149 次检测，假阳性率为 5.5%，假阴性率为 28.6%。淋巴结肿大和肺结节是假阳性的主要原因，而黑色素瘤、低期乳腺癌和前列腺癌是最常见的漏诊癌症（假阴性）。结论 新诊断特发性炎症性肌病成年患者的癌症抗原 125 （CA-125） 和 PET/CT 检测普遍存在假阳性和假阴性结果。了解这些不准确的原因可以帮助临床医生在患者护理期间做出明智的决定。