No, I’m not an expert.
My last post was just published on the news/blog aggregate site, Opposing Views, and received this comment:
“To opine that early detection does not matter when she benefited from it herself in order to make a separate point about MBC is a desperate attempt to sound like an ‘expert’ which obviously she is far from.
There is no cure for MBC, but she [meaning me] is living proof that her cancer was contained and small enough giving her every reason to expect to live a long life. It is quite the specious jump to compare a case of DCIS to MBC to gain attention. What’s worse, is in the same breath she says mammography does not find early cancer but her early cancer was found by mammography is misleading and irresponsible.”
Far from making me angry, it pointed up to me how hard it is to summarize complex information in the space of a blog post. I try to provide links to the references and resources I use to write my posts, and then attempt to summarize their findings. But I know that everyone does not have the time or inclination to click on every link to find out whether I’m just full of hot air or whether I can back up what I say. And sometimes, no matter what I say or how I say it, I just don’t manage to get my point across or my words and intent are misunderstood.
So, in this post, I’m going to provide some data. It’s unlikely to make anyone happy, but perhaps it will help to underscore some of the points I was attempting to make in my last post, which are:
- Screening mammography is different from diagnostic mammography.
- Screening mammography overall has been associated with only a small reduction in breast cancer mortality.
- Mammography in general is an imperfect tool for detecting breast cancer, particularly for younger women with dense breast tissue.
- Currently, mammography is one of the few tools we have, and we need better tools.
- Despite the increase in screening mammography, the mortality rate from metastatic breast cancer has remained virtually unchanged over the past twenty years, and the incidence of invasive breast cancer in women has, in fact, risen from 1 in 11 to 1 in 8 since 1975.
- Current treatment can sometimes slow or stabilize metastatic breast cancer, but we have no treatment at present that can stop it.
As for the rest of the commenter’s remarks, the inclusion of DCIS in my last post was obviously misunderstood and the context for it was apparently missed. To restate the issue, DCIS is an interesting and illustrative subject in the realm of the entire discussion of breast cancer because:
- Perhaps the one unqualified ‘success’ that may be ascribed to screening mammography is that it has helped to find far more incidences of DCIS over the years.
- Previous studies indicate that 14 to 53% of DCIS incidences may develop into invasive breast cancer.
- We do not yet know how to tell which types of DCIS may become invasive. So, despite the fact that some of them may not, we have to treat all of them as if they will.
- We also do not know yet how to predict with certainty whether any woman with any type of breast cancer will develop metastatic disease.
- All breast cancer treatment, including that for in-situ ductal and lobular carcinomas, is aimed at preventing the development of metastatic breast cancer.
It’s not like I make this stuff up. First of all, here’s a link to the lengthy report, with research references, published by the National Breast Cancer Coalition, from which, along with what I learned at their recent conference, I have gleaned my information.
It’s a downloadable PDF and I encourage everyone to browse through it. From the report:
“A great deal of attention and resources have focused on the area of early detection. A mantra that has been drummed into our consciousness over the past forty years is that early detection saves lives. The reality is otherwise. About 70% of women in this country over age 40 have had a mammogram in the last two years. Unfortunately, randomized controlled trials for mammography have shown, at best, a marginal benefit.[6,7] Breast self-exam (BSE) has also long been a key women’s health mantra. But research has demonstrated that routine BSE does not lead to a decrease in mortality from breast cancer nor does it find breast cancer at an earlier stage.[8,9]”
While I am the first one to recommend that research findings be viewed with some healthy skepticism, study results that admit to ‘bad news,’ that do not appear to benefit the researchers or the tools, treatments or medications they report on, are hard to refute. The NIH has made hundred of research citations and results available on the subject of breast cancer. Here is a link to a PDF of the studies on the efficacy of screening mammography in reducing breast cancer mortality. From the data synthesis:
“Mammography screening reduces breast cancer mortality by 15% for women age 39-49 (relative risk [RR] 0.85; 95% credible interval [CrI], 0.75-0.96; 8 trials). Results are similar to those for women age 50-59 years (RR 0.86; 95% CrI, 0.75-0.99; 6 trials), but effects are less than for women age 60-69 years (RR 0.68; 95% CrI, 0.54-0.87; 2 trials). Data are lacking for women age 70 years and older. Radiation exposure from mammography is low. Patient adverse experiences are common and transient and do not affect screening practices. Estimates of overdiagnosis vary from 1-10%. Younger women have more false-positive mammography results and additional imaging but fewer biopsies than older women. Trials of CBE [Clinical Breast Exams] are ongoing; trials of BSE [Formal Breast Self-Exams] showed no reductions in mortality but increases in benign biopsy results.”
What this states is that, for women between the ages of 39 and 59, there is about a 15% reduction in breast cancer mortality associated with screening mammography. I’m glad to hear that it has done some good. And I have not ever said anywhere that I think women should stop having screening mammograms. But the crucial points here are:
- A 15% reduction in breast cancer mortality among women who have had screening mammograms means that for the other 85%, screening mammograms made no difference in reducing breast cancer mortality.
- There were no studies cited in this portion of the NIH report for women under the age of 39, a population for whom breast cancer is often more aggresive, and for whom mammography is often ineffective in detecting breast cancer due to breast tissue density.
As early as 2003, a review of much of the data on breast cancer screening, published in 2003 in the Journal of the American Board of Family Medicine, found errors in the studies then available showing that screening mammography was effective in reducing mortality. Some studies done by Canadian researchers showed no benefit at all. In one study, CBE, performed by a doctor during an office exam, found breast tumors that mammography had missed, and other studies showed that women found their own tumors, from 55% to 65% of the time, whether they were screened by mammography or not. The self-discovery of these tumors were found by both formal BSE and informal palpation, with no increase in detection demonstrated by BSE over informal palpation.
Finally, I just want to reiterate the explanation I included in a comment on my last post about the difference between screening and diagnostic mammography:
The basic technology is the same for both screening and diagnostic mammograms, but the specificity & number of images done are different. Screening mammograms are done for women who do not have any symptoms. They take only a few standard views of each breast. Diagnostic mammograms are for checking breasts that have symptoms or for women who have had breast cancer in the past. They take more views from various angles and usually zero in on any suspicious area. Often, the mamm tech will place small stick-on markers over the nipple or previous scars or any other area that needs to be highlighted.
So, now you have some hard data. It still doesn’t make the conclusions easier to swallow. It doesn’t change the fact that we need better screening techniques. It doesn’t change the incidence of invasive breast cancer, which has, in fact, increased since 1975. And for women with metastatic breast cancer, it doesn’t change the odds.
I think we can all agree that what we want is real survival. Please don’t shoot the messenger.
Breast Cancer Deadline 2020 — Why Now?
Metavivor Research and Support, Inc., for women and men with metastatic breast cancer.
Metastatic Breast Cancer Network
Theories on Metastasis: An Advocacy Perspective, a presentation Musa Mayer made in a Leadership Training workshop at the recent NBCC Conference.
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