印度霍米巴巴国立研究所Indraneel Mittra团队研究了临床乳腺检查筛查对20年后乳腺癌发病率和死亡率的影响。2020年2月25日，该研究发表在《英国医学杂志》上。

为了探讨与未筛查相比，通过临床乳腺检查筛查在降低乳腺癌诊断和降低疾病死亡率方面的有效性，研究组进行了一项前瞻性、整群随机对照试验，在印度孟买选择了20个地理位置不同的集群，将其随机分配到10个筛查和10个对照集群；总试验持续20年。共涉及151538名年龄在35-64岁，无乳腺癌病史的女性。

筛查组的女性（n=75360）每两年接受一次临床乳腺检查和癌症认知筛查，共进行四轮，之后每两年进行一次主动监测，共进行五轮。对照组的女性（n=76178）接受了一轮癌症认知，然后每两年进行一次主动监测，共进行八轮。主要观察指标为乳腺癌诊断分期降低和乳腺癌死亡率的降低。

筛查组的乳腺癌平均检出年龄为55.18岁，显著早于对照组（56.50岁），患有III或IV期疾病的女性比例为37%，显著低于对照组（47%）。在整个研究人群中，筛查组每10万人-年死亡20.82例，对照组每10万人-年死亡24.62例，筛查组与对照组相比，乳腺癌死亡率降低了15%。然而，事后亚组分析显示，50岁及以上女性乳腺癌死亡率相对降低近30%，但50岁以下女性死亡率并没有显著降低。筛查组与对照组相比，全因死亡率降低5%，但无统计学意义。

研究结果表明，女性在基层卫生机构每两年进行一次临床乳腺检查，可显著降低乳腺癌诊断时的发病率，总体乳腺癌死亡率降低15%，其中年龄≥50岁的女性死亡率降低近30%，50岁以下女性的死亡率没有明显下降。

附：英文原文

Title: Effect of screening by clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomised controlled trial in Mumbai

Author: Indraneel Mittra, Gauravi A Mishra, Rajesh P Dikshit, Subhadra Gupta, Vasundhara Y Kulkarni, Heena Kauser A Shaikh, Surendra S Shastri, Rohini Hawaldar, Sudeep Gupta, C S Pramesh, Rajendra A Badwe

Issue&Volume: 2021/02/24

Abstract:

Objective To test the efficacy of screening by clinical breast examination in downstaging breast cancer at diagnosis and in reducing mortality from the disease, when compared with no screening.

Design Prospective, cluster randomised controlled trial.

Setting 20 geographically distinct clusters located in Mumbai, India, randomly allocated to 10 screening and 10 control clusters; total trial duration was 20 years (recruitment began in May 1998; database locked in March 2019 for analysis).

Participants 151538 women aged 35-64 with no history of breast cancer.

Interventions Women in the screening arm (n=75360) received four screening rounds of clinical breast examination (conducted by trained female primary health workers) and cancer awareness every two years, followed by five rounds of active surveillance every two years. Women in the control arm (n=76178) received one round of cancer awareness followed by eight rounds of active surveillance every two years.

Main outcome measures Downstaging of breast cancer at diagnosis and reduction in mortality from breast cancer.

Results Breast cancer was detected at an earlier age in the screening group than in the control group (age 55.18 (standard deviation 9.10) v 56.50 (9.10); P=0.01), with a significant reduction in the proportion of women with stage III or IV disease (37% (n=220) v 47% (n=271), P=0.001). A non-significant 15% reduction in breast cancer mortality was observed in the screening arm versus control arm in the overall study population (age 35-64; 20.82 deaths per 100000 person years (95% confidence interval 18.25 to 23.97) v 24.62 (21.71 to 28.04); rate ratio 0.85 (95% confidence interval 0.71 to 1.01); P=0.07). However, a post hoc subset analysis showed nearly 30% relative reduction in breast cancer mortality in women aged 50 and older (24.62 (20.62 to 29.76) v 34.68 (27.54 to 44.37); 0.71 (0.54 to 0.94); P=0.02), but no significant reduction in women younger than 50 (19.53 (17.24 to 22.29) v 21.03 (18.97 to 23.44); 0.93 (0.79 to 1.09); P=0.37). A 5% reduction in all cause mortality was seen in the screening arm versus the control arm, but it was not statistically significant (rate ratio 0.95 (95% confidence interval 0.81 to 1.10); P=0.49).

Conclusions These results indicate that clinical breast examination conducted every two years by primary health workers significantly downstaged breast cancer at diagnosis and led to a non-significant 15% reduction in breast cancer mortality overall (but a significant reduction of nearly 30%in mortality in women aged ≥50). No significant reduction in mortality was seen in women younger than 50 years. Clinical breast examination should be considered for breast cancer screening in low and middle income countries.

DOI: 10.1136/bmj.n256

Source: https://www.bmj.com/content/372/bmj.n256