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The math of invasive breast cancer risk for LCIS
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.
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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 ❤️
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1 ReactionI 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.
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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3 ReactionsMammeogram next week. Let's hope all is well.
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2 ReactionsI 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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1 ReactionTurns out my risk is even higher than 30%. Mayo recent study shows a much lower dose of tamoxifen is pretty much as effective as the higher dose. I have started on it due to my high risk. Switched to Mayo Clinic for my care.
I was 49 when I was diagnosed with LCIS. I had a lumpectomy and followed up with 5 years of tamoxifen. Side effects were minimal at first but my uterus started growing like crazy so I had it removed. There was no cancer but many polyps. At age 63 I was diagnosed with invasive lobular cancer in the same breast, pretty much the same area. I’ve gone through another lumpectomy followed by 20 radiation treatments. I am taking Anastrozole and of course experiencing many side effects. I have been on a plant based diet for over 6 years now, maintained a healthy weight and have a regular Yoga practice. I also have been frustrated with the lack of research done on LCIS. It might not be called cancer but...So we live each day with as much joy as we can, make the best choices we can and lean on one another for support. Thanks for this opportunity to share.
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4 ReactionsYour history is a lot like mind. Except I had Brachytherapy and an Ablation.
Do you have a family history of breast ca? My Mom had ca when she was 28. It metastasized when she was 39 and she passed on at age 43. I don’t test positive for any genetic mutations KNOWN but can’t help to think that there is a connection.
I was diagnosed with LCIS six years ago and Invasive Lobular Cancer four years ago. I had a lumpectomy with the LCIS and then a bi lateral mastectomy with the invasive four years ago. I have tried all the drugs and have had significant side effects, so I was unable to take them all, starting with Tamoxifen and trying Letrozole and Arimidex. I chose the bi lateral mastectomy because my LCIS was in my left breast and the invasive was in the right. I'm hopeful that will reduce my risk but the statistics don't always show that these days. I did not have to do radiation or chemo as my nodes were clear. I was 56 years old when I had the bi lateral. I was post menopausal. Thought I'd share that to go with the stats above.
Just this past November I had a scare with cellulitis from my lymphedema (with only one node removed in surgery, unlucky I guess) and it moved quickly to sepsis. I am recovering from that mess now AND while in recovery....my Mom, who is 83 was diagnosed with DCIS (Ductal Carcinoma in Situ)....I was the first person in my family for generations to have breast cancer, so I wouldn't think there was any genetic connection but now with my Mom (?)....however hers is ductal. My sister did die of lung cancer however about 9 years ago. I believe cancer is sometimes linked to family/genetics but more likely to environment and I think ours is consistently more polluted (but I have no real scientific basis for that).
Hugs to all