My last two posts addressed mammogram recommendations in the recent US Preventive Services Task Force (USPSTF) report on breast cancer screening. I also have some thoughts about the task force's comments on self and clinical breast exams.
For decades, physicians and breast cancer advocacy groups have recommended a monthly self breast exam (SBE) for adult women. I am not sure exactly when or from where this concept originated.
Monthly SBE apparently seemed like such an obvious good idea, it became standard medical advice without first being tested . Monthly self breast exams, yearly clinical breast exams (CBE) and regular mammograms after a certain age have been longstanding major components of breast cancer screening in the US.
Increasingly in medicine, we are trying to figure out which of our screening practices actually work. In the US, it would be very difficult to study SBE as a primary screening test, in the absence of CBE and mammograms. So studies on the effectiveness of SBE have come from countries where other breast cancer screening is not readily available.
A major study on SBE, conducted in China, involved 266,064 women, half of whom were repeatedly instructed in SBE and reminded to do the exams. None of the women had access to CBE or mammograms.
After 10 to 11 years of followup, the women who did SBE had the same breast cancer mortality as the control group. The main difference between the two groups was the SBE group had twice as many benign breast biopsies. A smaller study in Russia also showed no measurable SBE benefit.
On the face of it, these results seem contrary to many women's experience, as a fair number of breast cancers are found by women themselves.
Sometimes women examine their breasts because some life event made them worry in particular about breast cancer. Or, they became aware that their breast looked or felt different and then they did a self exam. Only rarely does one of my patients tell me she found a worrisome lump while doing her regular exam.
SBE every month is much too often to note meaningful change. Even if an area contains breast cancer, it is unlikely to feel different from one month to the next. Perhaps women themselves intuitively have always known this, as the majority have never done monthly exams.
The USPSTF agrees with what most women actually don't do and recommended against SBE for women at average risk for developing breast cancer.
For women at high risk for breast cancer, SBE appears to be more helpful. At the 2009 American Society of Breast Surgeons annual meeting, a small study found high risk women doing SBE every six months were as accurate as annual mammograms and MRIs in identifying breast cancers.
Being well-trained in SBE may be particularly important for younger high risk women who have not yet begun screening with mammograms.
And what about the clinical breast exam? The USPSTF found no evidence that CBE by itself reduces breast cancer mortality.
In the US, most women who have regular clinical breast exams also have access to mammograms. It would be difficult, probably ethically impossible, to do a large study of CBE as a stand alone screening test.
Physicians consider breast exams to be an important part of a woman's annual physical. Yet, many physicians could approach breast exams in a more thorough, systematic way. An optimal CBE takes at least one minute per side, with the entire breast being systematically evaluated. Ideally, visual inspection is also done.
If all clinicians perfomed CBE in a more structured, standardized manner, the effectiveness of CBE, though difficult to measure, would almost certainly improve.
So what are women to do? Women at high risk for breast cancer may benefit from learning to do SBE and doing an exam periodically. A six month interval seems reasonable and has a little data to back it up. Women at average risk should be aware of changes in their breasts and seek medical advice about persistent changes.
And all women who have their breasts examined by a medical professional should get the potential benefit of a thorough exam.
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