Confused about significance of Ki-67

From what I understand, Ki-67 is another factor taken into consideration when deciding on a treatment course after surgery. When I had my recurrence last year, my score was 29, whereas 8 years ago at my first diagnosis, my score was 6. My surgeon and oncologist both take the score into consideration, but not as a sole factor for decision making purposes. It seems that not everybody agrees on the significance of a high Ki-67 score. Of more concern is tumor size, grade, and lymph node involvement.

When I consulted at Sloan Kettering, the doctor there said that it also helps to classify a cancer as Luminal A or B. If your PR score is very low or negative, plus your Ki-67 score is high, then you're classified as a Luminal B cancer, which has a less favorable outcome in general than Luminal A. My second cancer is considered Luminal B, but again, that alone isn't determining treatment. I had the recurrence surgically removed, went through 30 radiation sessions, and am on an AI. This would have been the prescribed treatment regardless of my Ki-67 score.

Since Ki-67 measures the mitotic rate of growth, the higher the score, the faster the tumor is growing, therefore the higher potential grade of the tumor. The key is to have it removed ASAP and move forward with your treatment. I've been told not to be overly focused on that score because of the lack of clarity as to its overall prognostic significance, as well as the variability in actually scoring it (i.e. pathologists differ in their scoring even based on the same tumor sample).

Best wishes as you prepare to move forward!

Yes, the learning curve is huge, but it's amazing how quickly we can gather and synthesize the information when we're faced with such critical decisions!

Good idea to wait on emotionally settling in to a surgical decision. Definitely factor in the genetic results, that's key. The fact that you're so highly ER and PR positive means that you're an excellent candidate for hormone therapies following surgery. Depending on whether you're pre or post-menopausal, you may be offered Tamoxifen or an Aromatase Inhibitor. You'll also want to find out your Oncotype score, which is a prognostic indicator for recurrence and helps guide the decision for adding chemotherapy to your treatment plan.

Don't let the high Ki-67 score make you feel rushed in your surgical choice, however. In other words, it's not so worrisome that you need to feel like you want a lumpectomy ASAP before you can do your research on mastectomy with or without reconstruction. Whatever choices you make now will have long term, lifelong consequences, so take the time to educate yourself like you're doing, and don't panic about that score. You don't want to sit around for months trying to decide, but you also don't need to be in surgery tomorrow.

Dear S12Clear,

my name is Desiree, I am from Germany. I have been diagnosed in February 2016 with a triple negative breast carcinoma, KI67 at 80%. I completely freaked out on that number, scared to death. My onc was pretty much concerned too..In the course of my treatments, I insisted on a DNA based pathology of my tumour to confirm my hormone receptor status which was unclear (Luminal B or TN). The path report came back with a KI67 at 20%. You can easily imagine how confused I have been and I started to ask questions. The molecular pathologist told me that KI67 staining is very subjective and therefore not reliable.

All the best, Desiree

My Ki-67 is 70%. I am also Her2+. My MO wasn't/isn't concerned about my high Ki-67 so I don't worry about it either. I believe that my MO gave me the best current treatment available so I have to have faith in it.

Hi S12. I was dx 3 years ago in June 2014. Initial biopsy had my 2 tumors at 87% and 81% ki-67%!!! I was very freaked out and depressed when I did the research. I am also ER/PR+, HER2-. My doctor who is head of breast oncology at large cancer center said he used the number in his determination of treatment but didn't concern himself too much with it. He said all labs measure it differently. After surgery, the ki-67% on same tumors in final pathology report were 65% and 35%. Still crazy high but very different. Doctor said that the number is considered "unfavorable" but the higher the ki67% the more successful the chemo will be. It kills cells during a certain growth phase and since mine were turning quickly they would likely respond to chemo. Also...I was misdiagnosed 15 months prior to my cancer dx. I had scan done on a palpable lump that measured 5-6mm (was told benign/no follow up needed). 15 months later that same lump was 1.3cm (and determined to be cancerous)....so it basically grew a little over double. As awful as that is...I didn't think that sounded like a tumor growing out of control with ki67% over 80%. Not sure what a doc would say about all that but thats my thought. Also had larger tumor not detected at all initially. So many unknowns with this damn disease. Just wanted to share and hopefully help you worry about ki67 less.

I also had a high Ki67, I think around 60%. Both the MO and the RO mentioned it, but the MO said it's a highly subjective test (in regards to how they run it in the lab) and the RO said that my sample for it was "teeny tiny" which she said could affect the results, so they said in light of the rest of my pathology being favorable (luminal A), it didn't change their plans or recommendations. However, with a small tumor (1.2 cm) and one positive lymph node though, I wonder sometimes if those cells were more aggressive than we thought. I'm actually glad that my surgeon went ahead and ordered post-surgical scans, even though it may not have been necessary being earlier stage. It was nice to see those clear scans...

6 years ago my KI-67 was 15% and I still recently got a recurrence of DCIS, for now, so they say. It's my understanding that anything over 30% should be reason for concern. The lab did not do a test for KI-67 this go-around, but I will insist on a second opinion, with all the bell and whistles.

I was more focused on my ER/PR percentages, this time. That is more important, in my opinion.

Here's something interesting I'd like to share, Progesterone percentages. This higher the % the better the prognosis.

I added Source Naturals progesterone cream to my daily regimen. That was over 5 years ago. Shortly after I started applying the cream to my arms and inner thighs I noticed a small reduction in hot flashes. I have used it ever since. Honestly, I never gave it much stock that it would raise my PR levels. At that time my PR+ level was only 25%. This explained, in large part, why I had such a lousy score on OncotypeDX.

I finally got a hold of my Final Pathology report last week. The PR+ is shown at >50%. 6 years ago my ER+ was 99% and tamoxifen did some amazing damage to my cancer cells within a month! I don't have to tell you that although I was VERY disappointed with an ER+ at only slightly above 50%, I do take notice that the cream DOES work. It added 25% to my PR+ level. I take it!!

I'm in agreement with the others let your doctor know about the progesterone cream peppopat. I've just been identified with a reacurrance of my original tumor. I have lobular breast cancer. ER100% but PR-. As far as I can figure out I'm luminal A because my k67 is 1%. If my k67 had been above 14 I'd be luminal B .

S12clear let me know what he/she says. I didn't ask my oncologist unfortunately. I'm just learning as we all are.

I have a Ki67 of 60%. I was concerned with this (almost 6 years ago ER+ PR- Her2- with a high oncotype score of 39), but found a research article that determined a Ki67 of 55% was ideal with chemo. Could never find that research paper again.

I had a ki67% of 20, which is the low end of high. I asked Genomic Health, the maker of the Oncotype Dx test, about it and their test has other markers of proliferation included along with the ki67%. I also had a grade 3 (or 2, depending on the hospital) tumor. But my Oncotype score was 8. No chemo. The Oncotype test will help. My understanding was that I didn't need chemo due to high Er/Pr responsiveness but it is also possible that my cancer would not respond well to chemo for whatever reason. Chemo works best with cells that are dividing rapidly. (And my Oncotype and clinical pathology differed on that count.)

peppopat: I believe you might be thinking the hormone tests are of levels in our body. But they are tests of the responsiveness of our cancer to those hormones. If a tumor is fed by a hormone, then taking additional amounts of that hormone could be dangerous. That said, I don't know much about the idea of opposing estrogen-fueled growth by using bioidentical progesterone cream.

Yes, same side.

Now that you mention it, I should probably clarify that in my profile.

Well it looks like I'm the "winner", with a KI67 of 96%. However, a follow up ultrasound shows my tumor growing slowly. Additionally, my MO said they don't put too much significance on the KI67 as it is an unreliable test and many places don't even use it because it can be so inaccurate. My greater concern is that my doctors have doubts about all my numbers (ER/PR and her2) somthe plan is lumpectomy and SNB, then we'll start over with the pathology from the surgery.

This stuff is quite a challenge, isn't it

S12Clear...I completely agree! As I'm reading the above posts I'm thinking why on earth do they do them then?? Just another invalid test in the BC world. They really need to do better. We deserve it!