University of Exeter Medical School, Exeter.
Br J Gen Pract. 2020 Jun 25;70(696):e457-e462. doi: 10.3399/bjgp20X709577. Print 2020 Jul.
Microcytosis (smaller than normal red blood cells) has previously been identified as a possible early risk marker for some cancers. However, the role of microcytosis across all cancers has not been fully investigated.
To examine cancer incidence in a cohort of patients with microcytosis, with and without accompanying anaemia.
Cohort study of patients aged ≥40 years using UK primary care electronic patient records.
The 1-year cancer incidence was compared between cohorts of patients with a mean red cell volume of <85 femtolitres (fL) (low) or 85-101 fL (normal). Further analyses examined sex, age group, cancer site, and haemoglobin values.
Of 12 289 patients with microcytosis, 497 had a new cancer diagnosis within 1 year (4.0%, 95% confidence interval [CI] = 3.7 to 4.4), compared with 1465 of 73 150 without microcytosis (2.0%, CI = 1.9 to 2.1). In males, 298 out of 4800 with microcytosis were diagnosed with cancer (6.2%, CI = 5.5 to 6.9), compared with 940 out of 34 653 without (2.7%, CI = 2.5 to 2.9). In females with microcytosis, 199 out of 7489 were diagnosed with cancer (2.7%, CI = 2.3 to 3.1), compared with 525 out of 38 497 without (1.4%, CI = 1.3 to 1.5). In patients with microcytosis but normal haemoglobin, 86 out of 2637 males (3.3%, CI = 2.6 to 4.0) and 101 out of 5055 females (2.0%, CI = 1.6 to 2.4) were diagnosed with cancer.
Microcytosis is a predictor of underlying cancer even if haemoglobin is normal. Although a benign explanation is more likely, clinicians in primary care should consider simple testing for cancer on encountering unexplained microcytosis, particularly in males.
小细胞性贫血（红细胞体积小于正常值）此前被确定为某些癌症的早期风险标志物之一。然而，小细胞性贫血在所有癌症中的作用尚未得到充分研究。
检查红细胞体积小的患者队列中癌症的发生率，包括有或无伴随贫血的患者。
使用英国初级保健电子患者记录的年龄≥40 岁患者的队列研究。
比较红细胞体积均值<85 飞升（fL）（低）或 85-101 fL（正常）的患者队列中 1 年内癌症发生率。进一步的分析检查了性别、年龄组、癌症部位和血红蛋白值。
在 12289 例小细胞性贫血患者中，497 例在 1 年内诊断出新发癌症（4.0%，95%置信区间[CI]为 3.7-4.4），而 73150 例无小细胞性贫血患者中，1465 例（2.0%，CI=1.9-2.1）。在男性中，4800 例小细胞性贫血患者中有 298 例诊断出癌症（6.2%，CI=5.5-6.9），而 34653 例无小细胞性贫血患者中有 940 例（2.7%，CI=2.5-2.9）。在女性小细胞性贫血患者中，7489 例中有 199 例诊断出癌症（2.7%，CI=2.3-3.1），而 38497 例无小细胞性贫血患者中有 525 例（1.4%，CI=1.3-1.5）。在小细胞性贫血但血红蛋白正常的患者中，2637 例男性中有 86 例（3.3%，CI=2.6-4.0），5055 例女性中有 101 例（2.0%，CI=1.6-2.4）被诊断出癌症。
即使血红蛋白正常，小细胞性贫血也是潜在癌症的预测指标。虽然良性解释的可能性更大，但初级保健临床医生在遇到不明原因的小细胞性贫血时，应考虑进行简单的癌症检测，特别是在男性中。
