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Mar 5, 2014 09:41AM
lightandwind, I didn't mean to suggest or imply that no one develops breast cancer from having fibrocystic breasts. Yes, it does happen. And I wasn't offended by your posts, but just concerned about the impression that they might leave with someone who is new and scared and comes to this board with a fibroadenoma or a cyst. I spend most of my time in the "Not Diagnosed" forum, and so many women arrive here with these conditions, often scared out of their wits. The vast majority of these women will never have any serious problem - and will never develop breast cancer - because they had a cyst or a fibroadenoma or fibrocystic breasts. And that's the point that I wanted to clarify.
I understand things through numbers, so let me lay out the numbers, starting with those from the link that you provided.
"The relationship between fibrocystic disease and the risk of developing
breast cancer has been established based on proliferative changes seen
in breast biopsies and the follow-up of patients. 70% of the female
patients present a non-proliferative fibrocystic process without any
risk of further development of cancer as compared with the rest of the
population. 30% of patients with fibrocystic disease present a
proliferative process with or without atypia. Those without atypia have a
risk of 1.5-2.0 X as compared to non-biopsied patients. Age, family
history and presence of microcalcification increases the risk factor in
those patients with proliferative lesions. It is recommended that the
pathologic diagnosis include the risk factor when fibrocystic disease is
So let's start here, with a well-established number:
- 60% of women have fibrocystic breasts. Then let's incorporate the information from this article.
- 42% of women have fibrocystic breast conditions that do not increase breast cancer risk.
According to this article, 70% of women with fibrocystic breasts are not at increased risk. They have non-proliferative changes, fibrocystic conditions that do not increase risk. Most cysts fall into this category. So does fibrosis, mild hyperplasia, fat necrosis, lipomas, and various other conditions.
- 18% of women have fibrocystic breast conditions that increase breast cancer risk. This is the other 30% of women with fibrocystic breasts, those who do have conditions that increase risk.
Some of these women have conditions such as sclerosing adenosis, complex cysts, moderate or florid hyperplasia without atypia - conditions described as 'proliferative lesions without atypia'. These conditions present a small increase in breast cancer risk, raising the risk by 1.5X to 2X. That sounds like a lot, but it's not. In North America, the average woman faces a 12.4% chance that she will develop breast cancer during her lifetime. That's the risk level we all tend to think we have, but in fact it's an 'average' risk, the risk faced by all women combined, whether they have a family history or not, whether they are BRCA positive, whether they have no risk factors at all, etc.. It's everyone's risk all blended together and averaged out.
The "1.5X to 2X the risk" estimates are not assessing risk against 'average' risk. These increases are instead measured against 'base' risk, the risk level that each of us starts out with just because we are women, before any of our individual risk factors are considered. Base risk is about 4% - 6% (recently I read 3% - 5% - but I'll err on the high side). So when it's said that proliferative lesions without atypia increase risk by 1.5X to 2X, it means that women with these conditions have a 6% to 12% risk of breast cancer (average risk: 9%). That's still below the average 12.4% risk that we all tend to think we have - and that's why these are considered to be low risk conditions.
Then there are the women who have fibrocystic breasts that include conditions such as ADH and ALH. These are 'proliferative lesions with atypia'. These conditions increase risk by 3.5X to 5X vs. base risk. So having these conditions put women at a 14% to 30% risk (average risk: 22%) to develop breast cancer. Where someone falls depends on whether they have other risk factors such as family history.
I don't know how the 18% is split - what percentage of these women have conditions without atypia vs. those who have conditions with atypia. But let's say it's half and half. So (finally!) here's how many women develop breast cancer because they have fibrocystic breasts:
- 9% of women with fibrocystic breasts have proliferative changes without atypia, which puts their average risk in the range of 9%, meaning that approx. 1% will develop breast cancer because of having this condition.
- Another 9% of women with fibrocystic breasts have proliferative changes with atypia, which puts their average risk in the range of 22%, meaning that approx. 2% will develop breast cancer because of having this condition.
- 3% of women have fibrocystic breast conditions that will lead to the development of breast cancer. In most cases, the particular condition that leads to the development of breast cancer is ADH or ALH. The rate of cancer from having cysts and fibroadenomas (without associated atypia) is just a fraction of a percent.
Of course, if you are one of the 3%, you don't care that the risk from having fibrocystic breasts is so low. But for the hundreds of women who come to this board every year who have fibrocystic breasts (and who may happen upon this thread), it's really not something that they could be worried about all, particularly if they do not have a condition with atypia. Of course, they should be diligent and they need to understand the specifics of their condition and whether in fact it does increase their risk or not. But in most cases, it doesn't.
My apologies to those bored by this, and my apologies for taking this discussion off track. I started writing this post not actually knowing what the final numbers would be (although I knew the risk would be low) - my curiousity was tweaked by lightandwind's posts and I wanted to see for myself how this would all add up.
Dx 9/15/05, DCIS-MI, 6cm+ Gr3 DCIS w/IDC microinvasion, Stage IA, 0/3 nodes, ER+/PR- “No power so effectually robs the mind of all its powers of acting and reasoning as fear.” Edmund Burke