The first time I had BC in 2007, my tumor markers were ok. I did not pay so much attention then. I was stage 0 with no lymph node involvement. The second time I had it, my tumor markers were in the 40s. I had stage 1 invasive BC with no lymph node involvement in 2018. Lumpectomies both time. Only 2 times since then have they been in the 30s. I had a full body CT scan and nothing showed it...that was in May 2019. They seem to be fluctuating from the 30s thru the 40s this time. My oncologist tests me for them, but is not alarmed at all. I took tamoxifen the first time...this time anastrozole...which I may stop and go on tamoxifen in April. That is to keep my bones healthy. I cannot tell you not to worry because I would be too, but a friend of mine was told by her doctor that he doesn’t use them because they are not definite and only cause fear in the patient when they go up. This time around I am still concerned, but much more relaxed about it. I think going for the scans is a good thing either way. If nothing shows up then just relax. My doctor has told me that the 40s are the magic number for me. The CA 27.29 is not supposed to be used as a diagnostic in early stage breast cancers.