Breast Cancer Awareness Month comes to culminates today in Australia with Pink Ribbon Day. This has been a great motivator for me to take a look at the latest literature on the subject. I must admit I’ve found a few surprises.
Mammograms remain controversial. According to the Cochrane Collaboration, one of the largest and most respected organizations that analyses medical research, mammograms remain a vexed method of diagnosis in breast cancer. Cochrane summarizes their latest systematic review linked above (Gøtzsche PC, Nielsen M. Screening for breast cancer with mammography. Cochrane Database of Systematic Reviews 2008, Issue 4. Art. No.: CD001877. DOI: 10.1002/14651858.CD001877.pub3):
Screening with mammography uses X-ray to try to find breast cancer before a lump can be felt. The goal is to treat cancer early, when a cure is more likely. The review includes seven trials that involved 600,000 women who were randomly assigned to receive screening mammograms or not. The review found that screening for breast cancer likely reduces breast cancer mortality, but the magnitude of the effect is uncertain. Screening will also result in some women getting a cancer diagnosis even though their cancer would not have led to death or sickness. Currently, it is not possible to tell which women these are, and they are therefore likely to have breasts or lumps removed and to receive radiotherapy unnecessarily. The review estimated that screening leads to a reduction in breast cancer mortality of 15% and to 30% over diagnosis and over treatment. This means that for every 2000 women invited for screening throughout 10 years, one will have her life prolonged. In addition, 10 healthy women, who would not have been diagnosed if there had not been screening, will be diagnosed as breast cancer patients and will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress for many months because of false positive findings.
There are further issues with mammograms that are less controversial. Firstly, younger (pre-menopausal) women have denser breast tissue that means it is more difficult for x-rays to detect cancer and secondly there is the fact that x-rays themselves are a form of ionizing radiation and a known cause of cancer.
US based Breast Cancer Action looks at some of the issues around early detection of breast cancer and throws light on the complexity of assessing ‘survival rate’.
The complex biology of breast cancer means that women diagnosed with “early” breast cancer fall into one of three groups.
One group has very aggressive disease that, no matter how small it is when it is found, cannot be effectively treated with the therapies that are currently available. These women will die of breast cancer eventually, no matter what treatment they are given, unless they die of something else first.
Another group of women diagnosed with breast cancer has a type of either non-aggressive invasive disease or some presentations of DCIS (ductal carcinoma in situ) that will never be life-threatening.
The third group has a type of breast cancer that responds to currently available treatments. Finding breast cancer earlier does increase the likelihood that treatment will work for women in this group.
‘Survival rate’ is a vexed issue. When your doctor talks of surviving cancer, the harsh reality is they mean only that you will be alive 5 years after you are diagnosed. Statistically you’ve a “cancer survivor”, even if you die 5 years and 1 day later. Due to the unique nature of breast cancer a 10, 15 or 20 year survival figure may be more useful in helping women choose treatment option.
Detecting breast cancer in younger women relies heavily on a combination of learning how to and regularly practicing breast self examination and from the age of 20, asking your doctor to manually check your breasts each year as well.
So who gets breast cancer in Australia?
In 2006 12,614 were diagnosed with breast cancer:
24% are under 50 y.o.
51% are aged 51-69
25% are over 70 y.o.
stats from The National Breast and Ovarian Cancer Centre
However, while there are more women alive 5 years after initial diagnosis than in the previous decade, the number of women with breast cancer is increasing.
Younger women diagnosed with breast cancer have a greater chance of having a more aggressive (and more life challenging) type of cancer.
Over 100 men a year are diagnosed with breast cancer. While this may seem a small number, they tend to be diagnosed later than women and there is less support infrastructure.
Is breast cancer caused by a virus?
There has been some media attention in recent years connecting the HPV (warts) virus with breast cancer. While some breast cancer samples have been found to contain various types of the HPV virus, and this could be an interesting strand of inquiry into unraveling the myriad of causes of breast cancer, the link is still shaky at best. The renewed attention appears to be more about beating up more support for the ‘cervical cancer’ vaccine than anything else.
However, even in a pro-vaccine article you don’t need a science degree to question the quantum leap that those supporting the pharmaceutical industry appear to be making:
The study is very small, meaning it needs to be reproduced using a much bigger group of women to be more credible.
The largest type of cancer HPV was found in was 5/13 cases of ductal cancer, the least aggressive type of breast cancer.
HPV was found in much fewer cases of the more aggressive and life threatening invasive ductal cancers, only 21% (3/14 tissue samples).
Other studies in 15 countries have found widely varying results form 4-86% of breast cancer tumours containing the virus. This raises questions of cross-contamination (in the PCR process) creating inaccurate results.
The HPV family encompasses at least 100 variations of the virus. Gardasil, the HPV vaccine used in Australia, includes only 4 varieties.
The presence of the virus alone does not translate into a definite cancer risk.
Take home message
Stop living in fear of breast cancer. Check your own breasts and get you doctor to check them on a regular basis.
Most breast lumps are not cancer, the stress of worrying that a lump is cancer may be more detrimental to your health than the lump itself. If you have a lump, call your doctor now rather than investing more time and energy in worrying about it.
Genetic mutations account for only a small percentage of breast cancers – diet and lifestyle are likely to be the biggest cause.
Avoid unnecessary hormonal medications. There is a proven link between hormone replacement therapy (HRT) and breast cancer. Despite the overwhelming evidence in 2002 and further studies published this year confirming the link, HRT continues to be prescribed in this country.
So-called “natural HRT” or “bio-identical hormones” may also carry similar cancer risks. As they are not as “natural” as women are lead to believe.
The use of hormones in younger women in the form of the pill, injections and implants must also raise questions.
We already know that
Avoid unnecessary x-rays. Does your chiropractor really need a full spinal series of x-rays to treat your back? Leave x-rays for emergencies or to rule out series pathologies.
Get more Vitamin D. There’s growing evidence that this necessary nutrient found in sunlight and seafood may prevent a fast growing number of cancers including breast cancer. The link will also take you to a guide that shows just how much sun exposure you need, in different Australasian cities, to be adequately protected.
There are many more simple ways to decrease your breast cancer risk – read and make a few changes, you’ll feel better for it.