Objective To quantify the predictive value of unexpected weight loss for cancer according to patient’s age, sex, smoking status, and concurrent clinical features (symptoms, signs, and abnormal blood test results). Design Diagnostic accuracy study (update). Setting Data from Clinical Practice Research Datalink electronic health records linked to the National Cancer Registration and Analysis Service in primary care, England. Participants 326 240 adults (≥18 years) with a code for unexpected weight loss from 1 January 2000 to 31 December 2019. Main outcome measures Cancer diagnosis in the six months after the earliest weight loss code (index date). Codes for additional clinical features were identified in the three months before to one month after the index date. Diagnostic accuracy measures included positive and negative likelihood ratios, positive predictive values, and diagnostic odds ratios. Results Of 326 240 adults with unexpected weight loss, 184 270 (56.5%) were women, 176 508 (54.1%) were aged ≥60 years, and 176 053 (54.0%) were ever smokers. 15 624 (4.8%) had a diagnosis of cancer within six months of the index date, of whom 15 051 (96.3%) were aged ≥50 years. The positive predictive value for cancer was above the 3% threshold recommended by the National Institute for Health and Care Excellence for urgent investigation in men aged ≥50 years and women aged ≥60 years. 17 additional clinical features were associated with cancer in younger men with unexpected weight loss, and eight in women. Positive likelihood ratios in men ranged from 1.43 (95% confidence interval 1.30 to 1.58) for fatigue to 21.00 (8.59 to 51.37) for rectal mass, and in women from 1.28 (1.16 to 1.41) for back pain to 19.46 (12.69 to 29.85) for pelvic mass. Abnormal blood test results associated with cancer included low albumin (positive likelihood ratio 3.24, 3.13 to 3.35) and raised platelets (3.48, 3.35 to 3.62), total white cell count (3.01, 2.89 to 3.14), and C reactive protein (3.13, 3.05 to 3.20). However, no normal blood test result in isolation ruled out cancer. Clinical features co-occurring with unexpected weight loss were associated with multiple cancer sites. Conclusion The risk of cancer in younger adults with unexpected weight loss presenting to primary care is <3% and does not merit investigation under current UK guidelines. However, in men aged ≥50 years, women aged ≥60 years, and younger patients with concurrent clinical features, the risk of cancer warrants referral for invasive investigation. Clinical features typically associated with specific cancer sites are markers of several cancer types when they occur with unexpected weight loss. Readers’ note This article is an updated version of a previously published BMJ paper that has since been retracted. This study is based on CPRD data and is subject to a full licence agreement, which does not permit data sharing outside of the research team. Code lists are available from the corresponding author.

中文翻译：

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优先考虑体重意外减轻的初级保健患者进行癌症检查：诊断准确性研究（更新）


目的 根据患者的年龄、性别、吸烟状况和并发临床特征 （症状、体征和异常血液检查结果） 量化癌症意外体重减轻的预测价值。设计 诊断准确性研究（更新）。设置数据 来自临床实践研究 Datalink 电子健康记录，链接到英格兰初级保健的国家癌症登记和分析服务。参与者：326 240 名成年人（≥18 岁），在 2000 年 1 月 1 日至 2019 年 12 月 31 日期间使用代码表示意外体重减轻。主要结局指标 最早减肥代码 （索引日期） 后 6 个月内的癌症诊断。在索引日期前 3 个月至索引日期后 1 个月内确定了其他临床特征的代码。诊断准确性指标包括阳性和阴性似然比、阳性预测值和诊断比值比。结果 在 326 240 例体重意外减轻的成年人中，女性 184 270 例 （56.5%），年龄 ≥ 60 岁 176 508 例 （54.1%），既往吸烟者 176 053 例 （54.0%）。15 624 人 （4.8%） 在索引日期后 6 个月内被诊断出患有癌症，其中 15 051 人 （96.3%） 年龄≥ 50 岁。癌症的阳性预测值高于国家卫生与临床优化研究所推荐的 3% 阈值，用于 ≥50 岁的男性和 ≥60 岁的女性的紧急调查。在体重意外减轻的年轻男性中，有 17 个额外的临床特征与癌症相关，在女性中，有 8 个与癌症有关。男性的阳性似然比范围从疲劳的 1.43 （95% 置信区间 1.30 到 1.58） 到直肠质量的 21.00 （8.59 到 51.37），女性的背痛从 1.28 （1.16 到 1.41） 到盆腔质量的 19.46 （12.69 到 29.85）。 与癌症相关的异常血液检查结果包括低白蛋白 （阳性似然比 3.24， 3.13 至 3.35） 和血小板升高 （3.48， 3.35 至 3.62） 、总白细胞计数 （3.01， 2.89 至 3.14） 和 C 反应蛋白 （3.13， 3.05 至 3.20）。然而，隔离时血液检查结果不正常，排除了癌症。与意外体重减轻同时发生的临床特征与多个癌症部位相关。结论 在初级保健机构就诊的体重意外减轻的年轻人患癌症的风险为 <3%，根据目前的英国指南，不值得调查。然而，在 ≥50 岁的男性、≥60 岁的女性以及具有并发临床特征的年轻患者中，癌症风险需要转诊进行侵入性检查。通常与特定癌症部位相关的临床特征是几种癌症类型的标志物，当它们发生时体重意外减轻。读者注：本文是之前发表的 BMJ 论文的更新版本，该论文现已被撤回。本研究基于 CPRD 数据，并受完整许可协议的约束，该协议不允许在研究团队之外共享数据。代码列表可从通讯作者处获得。