A study published in the New England Journal of Medicine in November 2012 concluded that mammograms ?overdiagnosed? breast cancer ? detected tumors that would never have led to clinical symptoms ? in 1.3 million U.S. women in the past 30 years. In 2008, breast cancer was overdiagnosed in more than 70,000 women, or 31 percent of all breast cancers diagnosed, the study estimates.
After a report about the study was published in local newspapers, Gregory Harper, MD, PhD, physician director of Lehigh Valley Health Network?s National Cancer Institute Community Cancer Centers Program, wrote a column to reinforce the importance and effectiveness of regular mammograms.
?Until we can determine with confidence which cancers require treatment and which do not, screening is required to find as many cancers as early as possible,? Harper wrote. ?Which woman is willing to take the chance that the breast cancer growing in her breast does not need to be found or treated when no one ? not the woman, not the radiologist, not the surgeon, not the cancer specialist ? can know that her cancer will not kill her? The goal of screening needs to be to find cancer early.?
The Annals of Internal Medicine this month also published an opinion piece that takes a similar stance.
Read Harper?s column below.
Learn how to make an appointment for a mammogram at one of Lehigh Valley Health Network?s Breast Health Services locations.
?Why Mammography??
Gregory R. Harper, MD, PhD
Physician Director, National Cancer Institute Community Cancer Centers Program at Lehigh Valley Health Network
The Morning Call recently reported the findings of another study questioning the value of screening mammography. The study, published in the New England Journal of Medicine, demonstrated an increase in the diagnosis of early stage breast cancer (as a result of screening), but also estimated that about 31 percent of all breast cancers detected by screening would not have led to medically significant symptoms. The number of cancers detected that would not have progressed to medically significant symptoms but were treated anyway is considered ?overdiagnosis,? and it is estimated that in 2008, 70,000 women were overdiagnosed by this definition. The authors conclude that screening mammography results in significant harm ? surgery, radiation therapy, chemotherapy and hormonal therapy, most often some combination ? that could (and should) be avoided in those women who don?t need it as a result of overdiagnosis.
The problem is that we do NOT know which women with early stage breast cancer do not need treatment.
Some additional clarification of the study findings is warranted. First, of the increased number of women diagnosed with early stage breast cancer, one third of them were women with a diagnosis of non-invasivecancer of the milk ducts (ductal carcinoma in situ, DCIS). Women with DCIS usually have the tumor removed (surgery) and if only the tumor is removed (lumpectomy), then the remainder of the breast is treated with radiation. In some patients (but not all), additional ?anti-estrogen? hormonal therapy is recommended to reduce the chance that the cancer will come back in the treated breast or that new cancer will arise in the opposite breast. Chemotherapy is NOT recommended in women with DCIS. So, for one third of the women with early stage breast cancer, chemotherapy is not given, and is therefore not causing harm.
For most women, a diagnosis of DCIS is good news, because for the majority of women, the diagnosed cancer will be cured with local therapy (surgery and radiation for lumpectomy, and surgery only for women who require removal of the breast ? mastectomy). Because we do not know which women with DCIS are at risk for either recurrence in the same breast, or a new cancer in the other breast, the current guidelines are to consider treatment for everyone. In practice, however, we do not treat everyone the same, and although local treatment to remove the DCIS from the breast is recommended for most patients, the hormonal therapy is limited to only those women who are at high enough risk for recurrence to warrant treatment. Many older women do not get additional hormonal treatment because the side effects and risks are simply not worth the benefit.
The authors make the case that better treatment of early stage invasive cancers have resulted in better outcomes. This is true. Better treatment has led to longer ?five-year? survival rates. But living five years is not the same as living cured, and the goal of chemotherapy and hormonal therapy for invasive breast cancer is to cure the patient. Again, because we cannot tell for sure which cancers are more likely to kill the patient and which cancers are not likely to affect the woman?s life expectancy, current guidelines recommend consideration of treatment for all patients. But, even in early stage hormonally sensitive (estrogen receptor positive, ER+) breast cancers, not all women get chemotherapy. And this gets to the central concern about decreasing screening mammography.
We are steadily learning how to tell which cancers need treatment and which do not. For example, in women with early stage ER-positive breast cancers, an analysis of the genetic pattern in their breast cancer will predict which cancers will benefit from chemotherapy and which will not. Thus, we now have the tools not to ?overtreat? those early stage cancers that do not need chemotherapy. We are beginning to use the same genetic assay to tell which non-invasive cancers (DCIS) will require radiation and which can be treated only with surgical removal.
The reality is that some cancers that are diagnosed do not require additional treatment and may have never become ?medically significant? if never discovered. Other cancers that are diagnosed, even if early, will lead to the patient?s death even with treatment.? And, still others, if found early, will be cured with treatment that if not given would result in the woman more likely dying of her breast cancer when it recurred.
Until we can determine with confidence which cancers require treatment and which do not, screening is required to find as many cancers as early as possible.? Which woman is willing to take the chance that the breast cancer growing in her breast does not need to be found or treated when no one ? not the woman, not the radiologist, not the surgeon, not the cancer specialist ? can know that her cancer will not kill her?
The goal of screening needs to be to find cancer early. The goal of research is to find out how to better determine what to do with cancer when it is found. If an early stage cancer can be predicted to not affect a woman?s life expectancy and will not grow to be a wound in her breast, then, by all means, leave it alone. Then, we can concentrate our treatments on those cancers that truly need to be treated.
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More information from Healthy You magazine on LVHN.org:
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