Epidemiology of Cancer Healthcare & Outcomes (ECHO) Group, Department of Behavioural Science, Institute of Epidemiology and Health Care (IEHC), UCL, London, United Kingdom.
Department of General Practice and Primary Care, Centre for Cancer Research, University of Melbourne, Melbourne, Australia.
PLoS Med. 2024 Jul 30;21(7):e1004426. doi: 10.1371/journal.pmed.1004426. eCollection 2024 Jul.
Identifying patients presenting with nonspecific abdominal symptoms who have underlying cancer is a challenge. Common blood tests are widely used to investigate these symptoms in primary care, but their predictive value for detecting cancer in this context is unknown. We quantify the predictive value of 19 abnormal blood test results for detecting underlying cancer in patients presenting with 2 nonspecific abdominal symptoms.
Using data from the UK Clinical Practice Research Datalink (CPRD) linked to the National Cancer Registry, Hospital Episode Statistics and Index of Multiple Deprivation, we conducted a population-based cohort study of patients aged ≥30 presenting to English general practice with abdominal pain or bloating between January 2007 and October 2016. Positive and negative predictive values (PPV and NPV), sensitivity, and specificity for cancer diagnosis (overall and by cancer site) were calculated for 19 abnormal blood test results co-occurring in primary care within 3 months of abdominal pain or bloating presentations. A total of 9,427/425,549 (2.2%) patients with abdominal pain and 1,148/52,321 (2.2%) with abdominal bloating were diagnosed with cancer within 12 months post-presentation. For both symptoms, in both males and females aged ≥60, the PPV for cancer exceeded the 3% risk threshold used by the UK National Institute for Health and Care Excellence for recommending urgent specialist cancer referral. Concurrent blood tests were performed in two thirds of all patients (64% with abdominal pain and 70% with bloating). In patients aged 30 to 59, several blood abnormalities updated a patient's cancer risk to above the 3% threshold: For example, in females aged 50 to 59 with abdominal bloating, pre-blood test cancer risk of 1.6% increased to: 10% with raised ferritin, 9% with low albumin, 8% with raised platelets, 6% with raised inflammatory markers, and 4% with anaemia. Compared to risk assessment solely based on presenting symptom, age and sex, for every 1,000 patients with abdominal bloating, assessment incorporating information from blood test results would result in 63 additional urgent suspected cancer referrals and would identify 3 extra cancer patients through this route (a 16% relative increase in cancer diagnosis yield). Study limitations include reliance on completeness of coding of symptoms in primary care records and possible variation in PPVs if extrapolated to healthcare settings with higher or lower rates of blood test use.
In patients consulting with nonspecific abdominal symptoms, the assessment of cancer risk based on symptoms, age and sex alone can be substantially enhanced by considering additional information from common blood test results. Male and female patients aged ≥60 presenting to primary care with abdominal pain or bloating warrant consideration for urgent cancer referral or investigation. Further cancer assessment should also be considered in patients aged 30 to 59 with concurrent blood test abnormalities. This approach can detect additional patients with underlying cancer through expedited referral routes and can guide decisions on specialist referrals and investigation strategies for different cancer sites.
识别出现非特异性腹部症状且患有潜在癌症的患者是一项挑战。在初级保健中，常用的血液检查来调查这些症状，但它们在这种情况下检测癌症的预测值尚不清楚。我们定量评估了 19 种异常血液检查结果在出现 2 种非特异性腹部症状的患者中检测潜在癌症的预测价值。
使用来自英国临床实践研究数据链接（CPRD）的数据，该数据与国家癌症登记处、医院事件统计数据和多重剥夺指数相关联，我们对 2007 年 1 月至 2016 年 10 月期间≥30 岁的在英格兰全科医生就诊时出现腹痛或腹胀的患者进行了基于人群的队列研究。在腹痛或腹胀出现后 3 个月内，对初级保健中同时出现的 19 种异常血液检查结果进行了癌症诊断的阳性和阴性预测值（PPV 和 NPV）、敏感性和特异性（总体和按癌症部位）的计算。共有 9427/425549（2.2%）名腹痛患者和 1148/52321（2.2%）名腹胀患者在就诊后 12 个月内被诊断为癌症。对于这两种症状，在所有≥60 岁的男性和女性中，癌症的 PPV 超过了英国国家卫生与保健卓越研究所（NICE）用于推荐紧急专科癌症转诊的 3%风险阈值。在所有患者中，约有三分之二（腹痛患者为 64%，腹胀患者为 70%）进行了两次血液检查。在 30 至 59 岁的患者中，几种血液异常将患者的癌症风险更新至超过 3%的阈值：例如，在 50 至 59 岁的女性中，出现腹胀时，癌症风险从 1.6%增加到：铁蛋白升高 10%，白蛋白降低 9%，血小板升高 8%，炎症标志物升高 6%，贫血 4%。与仅基于出现的症状、年龄和性别进行风险评估相比，对于每 1000 名出现腹胀的患者，评估中纳入血液检查结果信息会导致额外的 63 例紧急疑似癌症转诊，并通过该途径额外发现 3 例癌症患者（癌症诊断率相对增加 16%）。研究的局限性包括依赖于初级保健记录中症状编码的完整性，以及如果外推到血液检查使用率较高或较低的医疗环境中，PPV 可能存在差异。
在出现非特异性腹部症状的患者中，仅基于症状、年龄和性别进行癌症风险评估，可以通过考虑来自常见血液检查结果的额外信息得到极大改善。≥60 岁的男性和女性因腹痛或腹胀就诊的患者需要考虑进行紧急癌症转诊或检查。在同时出现血液检查异常的 30 至 59 岁患者中，也应考虑进一步的癌症评估。这种方法可以通过加快转诊途径发现更多潜在的癌症患者，并指导不同癌症部位的专家转诊和检查策略决策。
