Dr Coldman and colleagues are to be commended on their efforts to discuss the complex issues involved in helping women decide whether to participate in screening mammography (Information for physicians discussing breast cancer screening with patients, BCMJ 2013;55:420-428 [9]). Some points deserve clarification.

In the Health Notes intended for women they state, “Two possible benefits from breast screening include:
•    A reduced risk of dying from breast cancer.
•    The need for less intensive treatment for breast cancer.”

They should have been more specific.

1. Early detection allows breast conservation. Women need to know that the likelihood of mastectomy increases with an increasing time interval between mammograms.

2. Early detection allows avoidance of axillary dissection, which has the adverse complication of lymphedema.

3. I was surprised to see them understate the potential mortality reduction. They state, “If you choose not to screen, you run a slightly higher risk of dying because of having a breast cancer that wasn’t found and treated early enough.” Randomized trials underestimate mortality reduction because they include all women invited, even if they do not attend (noncompliance). But Dr Coldman himself has previously published that there was a 40% mortality reduction among women who chose to be screened in BC.[1] That is not a slight decrease.

4. Overdiagnosis is not important unless it leads to overtreatment. Until our oncologic colleagues (medical and surgical) are able to determine optimal treatment for cancers of varying threats to life, it behooves us to keep screening. If we discourage screening to prevent overtreatment, we lose the opportunity to discover lethal cancers at a stage when they can be optimally treated.

5. The authors admit the randomized trial data were obtained using film mammography, which is being phased out and replaced by digital. But they made no mention of tomosynthesis (3D mammography), which is arguably the future of mammography screening. Tomosynthesis addresses both sides of the risk-benefit equation. There is ample and growing scientific data showing it increases cancer detection by 30% while at the same time reducing false positives by 40%.[2,3]
—Paula Gordon, OBC, MD, FRCPC
Medical Director, Sadie Diamond Breast Program

References

1.    Coldman A, Phillips N, Warren L, et al. Breast cancer mortality after screening mammography in British Columbia women. Int J Cancer 2007;120:1076-1080.
2.    Rose SL, Tidwell AL, Bujnoch LJ, et al. AJR Implementation of breast tomosynthesis in a routine screening practice: An observational study. AJR Am J Roentgenol 2013;200:1401-1408.
3.    Haas BM, Kalra V, Geisel J, et al. Comparison of tomosynthesis plus digital mammography and digital mammography alone for breast cancer screening. Radiology 2013;269:694-700.

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Information for physicians discussing breast cancer screening with patients [9]