BRCA genes and breast cancer risk

Stats 101

From the NIH website

‘About 13% of women in the general population will develop breast cancer sometime during their lives (1). By contrast, 55%–72% of women who inherit a harmful BRCA1 variant and 45%–69% of women who inherit a harmful BRCA2 variant will develop breast cancer by 70–80 years of age .’

Lets start with the ‘13%’ of us who will develop cancer sometime during our lives. This number refers to cumulative risk. The NIH seem to be very confused about what this means. Cumulative risk cannot tell us about lifetime risk of developing cancer or how many women will be affected, it is simply the sum of the incidences of breast cancer at each year of age up to a certain age, 90 years in this case. That means the average incidence of breast cancer per year of life is about 0.1%.

Now lets say we are entering a lottery once a year for a 100 years with a 0.1% chance of winning each time. The chances of winning are the same each year, they don’t increase with the number of times we enter. However, adding up the chances of winning each year up to 100 years, for the ‘cumulative chance’, gives a figure of 10%. By NIH logic this means that 1 in 10 entrants will win a lottery that they have a 1 in 1000 chance of winning each year at some point during their lives.

Now lets see those with the BRCA mutation. ‘Up to 72% of women will develop cancer by age 70-80.’ ‘72%’ refers to the cumulative incidence. This gives an average incidence of breast cancer among women with the BRCA genes per age year of their life of about 1%.

Those who enter the lottery now have a 1% chance of winning each year. The chances of winning are the same each year, they don’t increase with the numbers of times we enter. However, adding up for the ‘cumulative chance’ and using the NIH logic means that 100%, every single entrant, will have won the lottery by the age of 100. If they live that long they just cannot loose. That is just plain nuts.

Can we know what percentage of people will win? We know that over 100 years there will be 100 winners, but the percentage will depend on how many people enter. Can we know the life time chances. Even with 100 goes the lifetime chance of winning will still be 1%.

From the breast cancer figures can we know the lifetime risk of getting a first time diagnosis? My risk as I move through life not getting a diagnosis is what it is for each age of my life. As a baby it’s nil and then may increase at 30-50. My risk at 70 is whatever the risk at 70 is, it does not need the risk of all the other previous years I managed to live through, without getting cancer, added to it. If I am unfortunate enough to get a diagnosis, say at 40, my risk in that year wasn’t influence by the previous years, nor do I need the years following to be added to the risk, as I am then at no risk of getting another first diagnosis. My lifetime risk is the risk at whatever age I either live to or get a diagnosis at. I don’t think ‘lifetime risk’ is even a statistical thing, just a way for the NIH to bump up the numbers.

Can we know the percentage of women who will get a diagnosis? In the general population without the mutation the risk is on average 1 in 1000 each year and let’s say they live until 100. So that’s 100 chances in 100,000 life years, or 1 in 1000 or 0.1% of women will get a diagnosis.

For the BRCA population the chances are allegedly 1 in 100 per life year, so if they live for 100 years, 100 chances in 10,000 life years or 1% of women.

The mutation appears to increase the risk of a diagnosis by an absolute value of 0.9%.

From the CDC website; ‘About 50 out of 100 women with a BRCA gene mutation will get breast cancer by the time they turn 70 years old, compared to only 7 out of 100 women in the general U.S. population.’

Should read; About 1 in 100 women with a BRCA gene mutation will get a diagnosis by the time they turn 70 years old, compared to only 1 in 1000 women in the general population.

There are many other problems with the NIH ‘information’;

The repeated use of the word ‘harmful’ is misleading. The BRCA genes may be correlated with; but have not been shown to be causative of cancer. They have allegedly some role in tumour suppression and not cancer initiation. This role is only surmised from animal, mostly mouse, models, which as well as being cruel are useless as it is not known if these genes have the same function in mice as in humans.

The one gene one protein model is also ancient history. What is actually going on is something much more interactive involving genes in the nucleus, RNA, the microbiome and environmental factors.

Women with a family history of cancer are much more likely to have mammography (which may itself cause cancer), leading to more diagnosis. Screening often leads to over-diagnosis of small cancers, and the treatment may be more harmful than the cancer. If more women who are considered at lower risk and without family history of cancer, and presumably without the gene, were screened and were then also over-diagnosed, the difference between the risk of diagnosis with and without the gene would be even smaller.

Women in the same families are often be exposed to the same toxins, stresses, lifestyle habits and socioeconomic factors, such as likelihood of smoking, excess alcohol or obesity, that are involved in the formation of cancers. Maybe the familial mutation is an innocent bystander. Perhaps the factors that caused the cancer also caused the mutation.

Women with BRCA genes do not have a higher risk of developing ‘aggressive’ cancers. ‘Patients with young-onset breast cancer who carry a BRCA mutation have similar survival as non-carriers. However, BRCA mutation carriers with triple-negative breast cancer might have a survival advantage during the first few years after diagnosis compared with non-carriers.’

The NIH goes on to recommend screening, chemoprevention (though ‘the role of these drugs in women with harmful BRCA1 or BRCA2 variants is not yet clear’) and cutting off ones breasts or taking out ones ovaries; ‘For example, in several studies women who underwent bilateral salpingo-oophorectomy (removal of Fallopian tubes and ovaries) had a nearly 80% reduction in risk of dying from ovarian cancer, a 56% reduction in risk of dying from breast cancer’. NB this is relative risk reduction. The absolute risk reduction of dying from these particular cancers, using these drastic measures, was just 2.6% and 4% and doesn’t mean that the surgery improved overall survival.

The mutations may be correlated with cancer, but are not shown to be causative. Perhaps the mutations are a cell mechanism to deal with trauma and part of the healing process. Supposing that cancer itself is an adaptation to stress; allowing tumours to encapsulate toxins to protect the rest of the body for example. Would it be sensible to suppress these processes or to cut off parts of a body that’s trying to heal itself, or to recommend removal of healthy breasts and ovaries prophylatically.

In the UK the incidence of at least one of the mutations is allegedly about 0.25% or 1 in 400, yet only about 0.1% or 1 in a 1000 women will get a diagnosis of breast cancer. In Chinese populations the incidence of the gene is higher around 0.38% or 1 in 265 women but breast cancer rates are much lower, around 1 in 28,000 women, although this is rising with increased westernisation, especially with more saturated animal fats in their diets. Lifestyle trumps genes.

I would be as non-plussed with a positive gene test as I would be with a positive ‘covid’ PCR. Just like the novel gene sequences found in one patient in Wuhan were declared, with no evidence, to be the cause of the patient’s symptoms, the novel gene sequences in one Irish family were simply declared to be the cause of breast cancer.

Just another lie by Pharma/Regulation to create fear and a market for lucrative testing, pills and procedures.

🐒

https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet

https://pubmed.ncbi.nlm.nih.gov/29337092/

https://pubmed.ncbi.nlm.nih.gov/32467295/