The math of invasive breast cancer risk for LCIS

Posted by elsie37 @elsie37, Sat, Mar 30 1:32am

Lobular Cacrinoma in Situ (LCIS) confers a risk of invasive breast cancer of about 2% a year, maybe a little less, when chemoprovention endocrine meds are NOT taken. If meds are taken, the risk is cut in about half, maybe even cut a little more, so 1% or less.

Furthermore, LCIS is a lifetime risk. That means any 40 year old woman diagnosed with LCIS who could expect to live until 85 has a lifetime risk of 2%/year x 45 more years of life = 90% lifetime risk of cancer. Let's say the risk is only 1.5% per year, to be wildly optimistic and not 2%, since some studies have indicated the annual risk is less than 2%. Then that comes out to a 67.5% lifetime risk, still a big number. (1.5%/year x 45 more years of life)

Other sources show a lifetime risk of developing invasive breast cancer with LCIS to be 20% with some showing up to 35%. Those results do not come out to 2%/year for most women, unless the diagnosis is made at around 65 years or older.

Examples: Age 65 at diagnosis with life expectancy of 85 years means if using even the lower 1.5%/year risk, it is 1.5%/year x 20 more years of life = 30% lifetime risk. Age 70 at diagnosis with life expectancy of 85 years, again using the 1.5% figure is 1.5%/year x 15 more years = 22.5% lifetime risk.

Even the halved annual risk of 1% over a lifetime that may be obtained by taking chemoprovention endocrine meds still does not add up to a halved 10%-18% (instead of 20%- 35%) life time risk of invasive breast cancer,

Example: LCIS diagnosis at age 40 with life expectancy of 85. 1%/year x 45 years to reach age 85 = 45% lifetime risk. While better than even odds for a 40-year old, I think many women would consider something that close to 50% of getting cancer to be too high, especially after investing 5-10+ years of taking risk-reducing drugs, which produce substantial side effects for many. But a diagnosis at age 55 with a 1% annual risk due to medications, would result in a 30% lifetime risk, if life expectancy was 85. (1%/year x 30 years = 30%)

Interestingly, I have repeatedly seen that of all the LCIS diagnoses, only 10%-20% are in women past menopause, so using ages 55-75 for examples to make the annual risk come out similar as lifetime risk does not reflect the reality of who has the most cases of LCIS. I have also read that the number of post-menopause LCIS cases, though now a minority, is growing. And I am one.

Some of us have high hopes of making it to 90+ if we've had many relatives who have lived that long, so that means that 2%/year (or the more optimistic 1.5% or even the 1% with drugs) really makes lifetime risk soar upward.

For women diagnosed in their 30s, or younger, those 2%s accumulate over an even longer period, so that the odds of invasive cancer could easily reach 100% over a lifetime. Or more, but of course that is not possible. However, no studies I have found warn of guaranteed invasive breast cancer (100%) for those with LCIS if you live long enough.

Something does not add up. Perhaps it is the mathematician, (me). Or my LCIS assumptions are wrong. Maybe risk does not increase in a linear fashion year after year, maybe it tapers off? It seems to me that either all the lifetime risk numbers out there from reputable sources are wrong or the 2%/year over a lifetime (halved or more with medication) is wrong. So that those of us with LCIS can decide what treatment is best, we need to know which numbers are right–and which are wrong.

Can the Mayo experts or the moderator or another poster shed some light? Thank you in advance.

Liked by amy11559

That was impressive. Personally for me just based on how the diagnosis has changed back and forth over the years from pre cancer to benign to “increased risk”. This was enough for me to make the decision of pbm. With that said I am not a good candidate for tamoxifen since I have RA to begin with. I did read somewhere that up to 40% are unable to stay on tamoxifen due to side affects. As others have said it’s not an easy decision either way. Now I am faced with the decision of implants or diep flap with the latest news on implants. Another scary decision. This is a journey even without a cancer diagnosis. Prayers to all of us faces with this decision on how to proceed.

Liked by elsie37

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@amy11559, have you had your pbm already? May I ask what age your diagnosis was?

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@elsie37

@amy11559, have you had your pbm already? May I ask what age your diagnosis was?

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My surgery is this week. I am 50 yrs old. I am scheduled for nspbm with expanders. I hope to do ok and I hope to have DIEP at some point in the next few months. I am honestly terrified but this past year when An enhanced 6 cm nodular nonmass was found on my mri I felt a total loss of control. This was only two months after having a biopsy that showed a benign fibroadeonoma on the other breast. The fear that went through me that week was worse. I felt betrayed after having mammos and Sonos every year and doing everything I was suppose to do. I always felt we as woman were in control by having our yearly mammograms. This year I found that lobular hyperplasia and chances doesn’t always show up on imaging and that mad me angry. One one of three surgeons agreed to remove the fiboadenoma along with the nonmass on the opposite side. That is where the alh was found

Liked by elsie37

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Tried anastrozole, side effects were so bad I had to stop taking it , I did not do well with no estrogen and I know I would not live to 90 and I am 64 now . It is a slow growing cancer , they said they got it all and i did 30 rads . This is also a chemo drug and I would have been on it 10
Years . Don’t let fear control your treatment

Liked by elsie37

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Thank you for your experiences and responses, @cancersucks and @amy11559. Amy, you decided to do the DIEP at a later date then your nspbm, why did you choose that instead of getting it all done at once, may I ask? Best of luck with your surgery and I understand you may not be checking online forums and responding for a while with your upcoming schedule, @amy11559.

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@elsie37

Thank you for your experiences and responses, @cancersucks and @amy11559. Amy, you decided to do the DIEP at a later date then your nspbm, why did you choose that instead of getting it all done at once, may I ask? Best of luck with your surgery and I understand you may not be checking online forums and responding for a while with your upcoming schedule, @amy11559.

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Hi. Thank you for your well wishes. The plastic surgeon did not think I was a good candidate for one procedure. I was originally upset but he explained why and the more I thought about it I felt so overwhelmed making the decision of what I wanted anyway (silicone, saline or DIEP). I felt a sense of relief not having to make that decision yet. The ps said since I am larger chested that does not make me a good candidate for direct implant. Also in February I had a bilateral lumpectomy with reconstruction and he felt putting a heavy implant at the time of the mastectomy would jeopardize the blood supply to the breast. I spoke to many woman who have been through this and was surprised to find that several have reconstruction the same way. It’s called immediate reconstruction but not direct.

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@elsie37

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Thanks for your additional info, @amy11559. The time frame seems very appropriate for your situation. I have thought about the timing as well and wondered if doing the operations separately would be less taxing on the body. That seems to be the case for you–and for the other women you spoke to.

Liked by amy11559

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But I am still wondering, how one set of facts regarding LCIS, based on National Center for Biotechnology Information (NCBI) research, can provide a risk of invasive breast cancer of 50%, 60%, 70% over a lifetime (when 2%/year is given) and other reputable sites like American Cancer Society state 20% to maybe 35% lifetime risk? Without accurate information, we cannot make decisions. And 20% compared to 70% is a huge discrepancy.

Liked by amy11559

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@elsie37

But I am still wondering, how one set of facts regarding LCIS, based on National Center for Biotechnology Information (NCBI) research, can provide a risk of invasive breast cancer of 50%, 60%, 70% over a lifetime (when 2%/year is given) and other reputable sites like American Cancer Society state 20% to maybe 35% lifetime risk? Without accurate information, we cannot make decisions. And 20% compared to 70% is a huge discrepancy.

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Completely agree. My alh pathology was an accidental finding at age 50. How do I know this hasn’t been there for 15 years. How can I get a 20 percent chance over 5-15 years of being discovered. Very unsettling

Liked by elsie37

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@amy11559

Completely agree. My alh pathology was an accidental finding at age 50. How do I know this hasn’t been there for 15 years. How can I get a 20 percent chance over 5-15 years of being discovered. Very unsettling

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Nothing correlates as far as I can see. They all seem to recommend cancer preventing drugs which come with its own set of risks. For me I was researching after a year of hell of waiting for biopsy results. One woman on a fb group page wrote. “Would you get on a plane if it had a 20 percent chance of going down.” Granted that is not a great example. I personally have lost trust in the system. For years I felt that I was doing everything so that I can catch something in time unlike many of my family members that have passed. My family tree is so sad. Never in my wildest dreams did I expect for a doctor to tell me that they have a hard time seeing lobular since it forms lines similar to those in normal imaging. I became angry. I hope and pray my pathology comes back ok. What I am doing tomorrow is making me feel in more in control than I have felt in years. I pray for all of us those who have gotten sick from implants and just anyone touched in any way by cancer because it affects everyone involved. I am so sorry you are thinking of all of this also. It is not fair and upsetting. Please message I will be happy to talk or exchange thoughts about the process I am going through or anything. Good luck ❤️

Liked by elsie37

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I posed that question to my oncologist –"Would you get on a plane if it had a 20 percent chance of going down?” Her response was that a plane going down and probably killing people is not the same as a diagnosis of breast cancer. And that is true, THANK GOD, that most women diagnosed with IBC do not suddenly die like they would in a plane crash.

But how about this? Would you eat at the best restaurant in the world if it gave you a 20% or so lifetime risk of invasive breast cancer? Let's even say it is free food! Even the Biggest Foodie in the World would not do it I'm pretty sure.

But here are some more stats that many sources agree upon: About 25% of all early stage cancers metastasize within 20 years. So, even given a 30% chance of cancer, if you get it then that is followed by 25% chance of metastasizing. So 30% x 25% and we are at 7.5% of metastasized cancer. That's too high!

@amy115599, your attention to the forums just before your surgery is commendable! 'llI check out the PM feature, but not for quite some time. You have other priorities now.

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I so can relate to this! I was told at first I had a 60% chance of getting breast cancer. Very scary! Mayo said my risk is 20-30%
Then I was in my opinion "over mammeod" as they did six (almost seven I refused the last one) in one year but that was NOT at Mayo, it was at Seattle Cancer Care… I went again to Mayo and will follow up care there. I am not willing to take the drugs, I have autoimmune issues, so these would be bad for me….The math for LCIS does NOT add up, I have tried to figure it out. Even good medical websites have risk ALL over the place….
I personally believe that we need more research into LCIS especially as to what our risk is. I know this is a rare issue, but this is something that could be possibly preventable from progressing……

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Mammeogram next week. Let's hope all is well.

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I would like to say that I think the current "preventative treatments" for LCIS are awful. We need better understanding and treatment if any. I chose to watch and wait with careful monitoring.

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