Re: Effect of screening by clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomised controlled trial in Mumbai
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Effect of screening by clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomised controlled trial in Mumbai
Re: Effect of screening by clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomised controlled trial in Mumbai
Dear Editor:
Mittra et al assessed the efficacy of screening clinical breast examination (CBE) in reducing breast cancer-specific mortality in Mumbai, and their results are consistent with those from the older mammography screening trials, demonstrating an age-interaction with respect to the efficacy of breast cancer screening (1) (2). Specifically, the mortality benefit of breast cancer screening seems to be largely confined to women aged 50 and older, with little or no benefit for women below age 50.
However, the Canadian National Breast Screening Study (CNBSS), demonstrated no mortality benefit from mammography screening when women aged 50 and older were randomized to screening mammography + screening CBE versus screening CBE alone, and the results of that trial might be interpreted to mean that screening mammography provides no additional mortality benefit beyond that which can be achieved by screening CBE alone(3). Clearly, over-diagnosis is a major concern with screening mammography, and much less so with screening CBE, and the risk of over-diagnosis will increase with use of more modern screening technology (i.e., tomosynthesis, magnetic resonance imaging), which increases the detection rates of more occult (non-palpable) cancers (4).
Taken together, the results of the Mumbai trial and the CNBSS suggest that a clinical trial randomizing women aged 50 and older to screening mammography versus screening CBE is now warranted. If such a trial demonstrates that there is no added benefit to mammography screening beyond that achievable with screening CBE, then screening CBE should replace screening mammography as the optimal breast cancer screening method.
1. Mittra I, Mishra GA, Dikshit RP, Gupta S, Kulkarni VY, et al. Effect of screening clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomized controlled trial in Mumbai. British Medical Journal, 2021
2. Kerlikowske K, Grady D, Rubin SM, Sandrock C, Ernster VL. Efficacy of screening mammography. A meta-analysis. JAMA. 1995;273(2):149-54.
3. Miller AB, Wall C, Baines CJ, Sun P, To T, Narod SA. Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial. BMJ. 2014;348:g366.
4. Jatoi I, Pinsky PF. Breast Cancer Screening Trials: Endpoints and Over-diagnosis. J Natl Cancer Inst. 2020.
Competing interests:
No competing interests
25 February 2021
Ismail Jatoi
Professor and Chief, Division of Surgical Oncology and Endocrine Surgery
University of Texas Health Science Center, San Antonio
University of Texas Health Science Science Center, 7703 Floyd Curl Drive, San Antonio, Texas 78229 USA
Rapid Response:
Re: Effect of screening by clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomised controlled trial in Mumbai
Dear Editor:
Mittra et al assessed the efficacy of screening clinical breast examination (CBE) in reducing breast cancer-specific mortality in Mumbai, and their results are consistent with those from the older mammography screening trials, demonstrating an age-interaction with respect to the efficacy of breast cancer screening (1) (2). Specifically, the mortality benefit of breast cancer screening seems to be largely confined to women aged 50 and older, with little or no benefit for women below age 50.
However, the Canadian National Breast Screening Study (CNBSS), demonstrated no mortality benefit from mammography screening when women aged 50 and older were randomized to screening mammography + screening CBE versus screening CBE alone, and the results of that trial might be interpreted to mean that screening mammography provides no additional mortality benefit beyond that which can be achieved by screening CBE alone(3). Clearly, over-diagnosis is a major concern with screening mammography, and much less so with screening CBE, and the risk of over-diagnosis will increase with use of more modern screening technology (i.e., tomosynthesis, magnetic resonance imaging), which increases the detection rates of more occult (non-palpable) cancers (4).
Taken together, the results of the Mumbai trial and the CNBSS suggest that a clinical trial randomizing women aged 50 and older to screening mammography versus screening CBE is now warranted. If such a trial demonstrates that there is no added benefit to mammography screening beyond that achievable with screening CBE, then screening CBE should replace screening mammography as the optimal breast cancer screening method.
1. Mittra I, Mishra GA, Dikshit RP, Gupta S, Kulkarni VY, et al. Effect of screening clinical breast examination on breast cancer incidence and mortality after 20 years: prospective, cluster randomized controlled trial in Mumbai. British Medical Journal, 2021
2. Kerlikowske K, Grady D, Rubin SM, Sandrock C, Ernster VL. Efficacy of screening mammography. A meta-analysis. JAMA. 1995;273(2):149-54.
3. Miller AB, Wall C, Baines CJ, Sun P, To T, Narod SA. Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial. BMJ. 2014;348:g366.
4. Jatoi I, Pinsky PF. Breast Cancer Screening Trials: Endpoints and Over-diagnosis. J Natl Cancer Inst. 2020.
Competing interests: No competing interests