This is a long one, dear readers, so grab a cup of coffee and put your feet up.
Thank you, Mrs. Ford.
In 1974, when she was 56, Betty Ford’s doctor found a lump in one of her breasts during a routine physical. At the time, biopsies were not done as a separate procedure to determine the nature of the lesion. Usually, surgical biopsy was done under anesthesia, the tissue examined while the patient was still on the table, and if it was found to be cancerous, a mastectomy was immediately performed. Betty Ford and her husband had just moved into the White House, after Richard Nixon left in disgrace, less than two months before her doctor found the lump. That same day, she and President Ford were scheduled to attend the dedication of a memorial for former president Lyndon Johnson. She put off surgery for 24 hours, and the day after her first physical as First Lady, she underwent a modified radical mastectomy. Talk about a baptism by fire.
The day after her surgery, she asked her husband to make a public announcement of her experience. As she told the American Cancer Society during a speech a year later, “one day I appeared to be fine and the next day I was in the hospital for a mastectomy. It made me realize how many women in the country could be in the same situation.” Before journalist Betty Rollin was diagnosed with breast cancer in 1975, before she wrote her book about it, First You Cry; before Audre Lorde wrote and published The Cancer Journals about her own experience with breast cancer, Betty Ford’s candor helped to bring the silent scourge of breast cancer into public view. It is not an overestimation to say that single-handedly, she did more for breast cancer awareness than anyone else had up to that point, and that her continued willingness to speak out helped women and men pay attention to possible symptoms, get screened and treated early, and helped save countless lives.
Mammography — what difference does it really make?
The beginnings of mammography go back to 1913, when it was used not as a prognostic tool, but as part of the post-op pathological examination of tissue removed during mastectomies. In 1930, it began to be used prognostically, to detect cancer before surgery, but it would be more than thirty years before the U.S. Public Health Service would sponsor a conference to report on the reliability and reproducibility of mammography, and to encourage its use as a tool to screen women for breast cancer to enable earlier detection. The Health Insurance Plan of New York would launch a long-term trial to study its effectiveness, and in 1971, published its findings, which demonstrated that screening mammography with five-year follow-up was associated with a reduction in breast cancery mortality of about 30%.
I don’t have to tell most readers of this blog that Betty Ford, whose cancer was, ironically, not detected by screening mammography, helped launch an era in which screening mammography was made available to all women, and encouraged as a regular preventative procedure for women aged forty and over for several decades. Then in 2009, the U.S. Preventative Services Task Force infamously declared that screening mammography for women aged 40-49 was not significantly effective, and recommended that regular biennial screening mammography for women should start at age 50.
Since then, further studies have added to the confusion and uproar. Indicative of much of the controversy is a recently published study in the Annals of Internal Medicine which concluded, logically enough, that “Mammography screening should be personalized on the basis of a woman’s age, breast density, history of breast biopsy, family history of breast cancer, and beliefs about the potential benefit and harms of screening.” Meanwhile, another study, published in the Journal of the American Medical Association, found that follow-up screening mammography for women who’d already had an incidence of early-stage breast cancer, often missed second occurrences or required longer screening intervals to pick them up. Yet another study, recently published in the journal Radiology, mirrored the early mammography results published by the HIP of NY in 1971. The so-called Swedish Study followed women aged 40-74 for twenty-nine years, and found that screening mammography was associated with a 30% reduction in mortality rate from breast cancer.
Relative versus Absolute
First of all, it’s important to keep in mind the difference between relative and absolute statistics, but it’s not always easy to determine which type are being reported in published studies. In the article linked here, the author provides this example:
Which drug would you rather take? One that reduces your risk of cancer by 50 percent, or another drug that only eliminates cancer in one out of 100 people? Most people would choose the drug that reduces their risk of cancer by 50 percent, but the fact is, both of these numbers refer to the same drug. They’re just two different ways of looking at the same statistic. One way is called relative risk; the other way is absolute risk.
My own personal story on this relates to tamoxifen, which I was placed on after my partial mastectomy and radiation treatment for ductal carcinoma in situ (DCIS). I was told that, after all my previous treatment, taking tamoxifen for five years would reduce my risk for a recurrence in the same breast (not, by the way, my risk for a new occurrence in the other breast) by 50%. Who wouldn’t want that? However, severe side effects drove me to stop taking the tamoxifen for a week to see how I would feel. When the side effects disappeared, I knew I needed more information to decide whether to stop it altogether. And what I discovered was that, taking into account my own pathology report, my diagnosis, and my previous treatment, tamoxifen in fact only reduced my risk of recurrence by 7.5%. Without it, my recurrence risk was 15%, so, yes, a 50% reduction of that was 7.5%. But meanwhile, I couldn’t work full-time anymore, I was broke, and I spent most of my free time exhausted and having a seriously poor quality of life. That made no sense whatsoever to me. Because in fact, I had an 85% chance of not having a recurrence without tamoxifen. I could not take aromatase inhibitors because of a family history of osteoporosis. So, I talked it over with my medical oncologist, and she agreed that it made more sense for me to stop hormone therapy altogether. That is when I truly woke up to the difference between relative statistics and absolute statistics.
So, where are we really?
The reality is that the 30% reduction in breast cancer mortality, reported in the Swedish Study, as well as the NY HIP study in 1971, represents relative reduction. Of the 77,080 subjects who received screening mammograms and were followed in the Swedish Study for 29 years, there were 351 deaths caused by breast cancer, which comes out to an absolute mortality rate of 0.455% of all the subjects in the screening group, or less than half a percent. Among subjects in the control group, who did not received screening mammograms but instead received passive examination, there were 367 breast cancer deaths among 55,985 subjects, or an absolute mortality rate of 0.655% from breast cancer over 29 years. If you compare these mortality rates, then 0.455% compared to 0.655% comes out to a 30% reduction in breast cancer mortality in the group that received screening mammograms, compared with the group that did not. The study determined that 158 breast cancer deaths were prevented over the 29 years in the group that received regular screening mammograms. This represents an absolute percentage of lives saved among all 133,065 study participants of 0.12%. Are you still with me?
DCIS — does it count?
Something else that’s important to keep in mind is that fully 20%, or one fifth, of all breast cancer found by screening mammography is DCIS, a non-invasive form of breast cancer found in the mammary ducts. With the current protocol of mastectomy alone or partial mastectomy or lumpectomy plus radiation, plus hormone therapy, the survival rate over five to ten years for DCIS is about 98%. Since screening mammography first became standard practice in the early to mid 1970’s, the incidence of DCIS found by screening mammography increased by over seventeen-fold by 2004. The Swedish Study did not distinguish between non-invasive and invasive breast cancers. So, how much has screening mammography really affected the mortality rate for invasive breast cancers? And why is non-invasive DCIS treated so aggressively? The answer to the second question is an open one. The simple answer is that we just don’t know yet, with any degree of certainty, how many of these incidences of DCIS will become invasive if left untreated and only monitored. We do know that some of them will, and researchers are actively trying to identify biomarkers, histological indicators and other measurable signs that can accurately predict which types of DCIS are more likely to become invasive if left alone. A review of DCIS published in the Journal of the National Cancer Institute last year examines this subject closely, and concludes that we just don’t have enough answers.
But the answer to the first question is more troubling. If we remove the statistics for DCIS from the statistics for all breast cancer incidence, then how well are we really doing? How much impact does screening mammography really have on the incidence and mortality for invasive breast cancer? We do know that, in the United States, the number of women dying from metastatic breast cancer has remained at about 40,000 deaths per year for the past thirty years. In a recent blog post by Gayle Sulik, author of Pink Ribbon Blues, called Mammogram Mania, Sulik examines some of these troubling questions. And once again, a simple change of perspective on the most optimistic relative statistics about mammography tells the tale. Even if we embrace the notion that screening mammography is associated with a relative 30% reduction in breast cancer mortality, that means that for the majority of women, screening mammography makes no difference at all. Indeed, per the Swedish Study, if all women between ages 40 and 74 got screening mammograms, then we might expect a comparable absolute decrease in breast cancer mortality of 0.455%, which is less than half of a percent over 29 years. And what about women who are under 40, who, when they are diagnosed with breast cancer, tend to have more aggressive cancers with a higher risk of metastaticizing? Mammography often doesn’t work well on the dense tissue that young women have. So far, most screening recommendations leave them out in the cold. And I have yet to see any stats on breast cancer mortality that include the person’s age at diagnosis.
Mammograms are what we’ve got.
The last time I attempted to elucidate this thorny subject, I was accused of implying that we shouldn’t bother having mammograms. I have never said that, and I’m not saying it now. Mammograms are what we’ve got, in terms of widely available and relatively simply screening tools, and until something better comes along, we can’t afford to stop having them. MRI’s, ultrasound, breast thermography and other tools also have their place in detection. Molecular breast imaging is a promising technology, but still requires too much radiation to be safe in wide use. The success of detecting DCIS has far outstripped the detection of invasive breast cancer, and for many of us with DCIS, we may be undergoing excessive and unnecessary treatment. Meanwhile, we need more accurate data on the detection and survival rates for invasive breast cancer, and we desperately need more effective treatment for metastatic breast cancer, which is what kills those 40,000 American women every year.
Let’s hope that this October, we can finally get beyond mere ‘boobie’ awareness and get to an awareness of how far we have yet to go and what we need to do to get there.
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