4 years ago, my sister was diagnosed with stage III colon cancer. At the time, the CEA (carcinoembryonic antigen) level in her blood was elevated. As we learned in class, this oncofetal antigen is found in the blood of patients with colon carcinoma and other cancers. After undergoing surgery and months of chemotherapy, her CEA level fell to zero and her PET scan came back negative.
Since then, every 6 months, she has blood work done to measure, among other things, her CEA level.
One year ago, she was 4-months pregnant with twins and at that time, her CEA level was still at zero. (Does anyone know at what stage the fetus starts producing CEA?)
Then, when she was 7-months pregnant, she was admitted to the hospital with excrutiaing pain in her right upper quadrant. After 5 days of tests and scans, they were able to rule out the gall bladder and kidney stones and yet she was on a morphine drip for the pain. Unfortunately, because she was preganant, the babies were in the way of the doctors being able to see where the problem was AND they were limited in the amount/type of scans they could do for fear of the effects of the radiation on the developing fetuses. Their (the doctors') suspicion was that the cancer was back. Normally, they informed us, they would check her blood for the cancer marker but because this marker is elevated in pregnant women, the test would be inconclusive. I would agree with this IF the test came back positive but what if it came back negative (as it was 3 months prior)? Couldn't that at least have offered my sister some much needed emotional relief, who at this time was facing her greatest fear - that she would give birth to twins and then be told that her cancer was back? Then again, perhaps the doctors knew that it would definitively be positive at this stage in her pregnancy.
As it turned out, the cancer was not back. The pain she was experiencing was due to one of the babies pushing on one of her ureters and blocking the flow of urine.
Reading about real world cases is very interesting. I don't know a ton about embryology or development, but I was under the impression that by 7-8 weeks gestation (5-6 weeks fetal age), the fetus begins to produce all of its hormones aside from the placental HcG, estrogen, progesterone, etc. So the CEA test would have been elevated regardless of the presence of cancer.
ReplyDeleteI'm also no expert on nuclear medicine, but could an MRI have been used on her instead of using radiation? If there were some surgical intervention, scar tissue could be confused for a suspicious lesion but it seems better than no scans at all. Either way, I'm glad it turned out to be a more benign diagnosis.
I'm glad this turned out to be a scare, and not a recurrence of cancer.
ReplyDeleteIn terms of her treatment, maybe staying in the dark about her CEA level was the best course of action to take at that point in time?
If the CEA did show a positive result, what could be done besides worry about it? Maybe surgical resection could have been done, but the option for adjuvant or neoadjuvant systemic therapy (not always part of the treatment plan, but sometimes it is) would be contraindicated due to preganacy.
Also, MRI contrast (gadolinium) passes through the placenta. My quick research showed that there have not been any longitudinal studies to determine the possible effects of this on a fetus/child. Since the effects are undocumented, it is a potential safety issue, the radiologists maybe considered this a contraindication.
Another thing, logistically, is that it could be pretty tight squeeze to fit a woman who is 7 months pregnant with twins into a MRI machine.
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ReplyDeleteI did a little research on this and found a few interesting articles. One measured the amount of CEA (and three other tumor-associated antigens) in healthy pregnant women for all three trimesters of pregnancy. They said that CEA levels during all three trimesters of pregnancy remained in normal levels, but did state that in another paper, CEA levels rose 12% and could give a false positive. Maybe if the doctors feared a fale positive, they did not run the test? Or maybe they thought it had something to do with the pregnancy?
ReplyDeleteHere are the links to the studies:
http://onlinelibrary.wiley.com/doi/10.1002/1097-0142(19801101)46:9%3C2091::AID-CNCR2820460930%3E3.0.CO;2-D/pdf
I'm not sure if you will be able to open the following link so I will also leave a citation after the link.
http://onlinelibrary.wiley.com.ezproxy1.library.arizona.edu/doi/10.1002/(SICI)1098-2825(1999)13:1%3C35::AID-JCLA7%3E3.0.CO;2-R/pdf
Measurement of four tumor marker antigens in the sera of pregnant women.
Journal of clinical laboratory analysis, 1999; 13(1): 35-9
I hope this helps.
Thank you KellyG for the post.
ReplyDeleteI actually had not heard of potential normal elevation in tumor markers in pregnancy prior to this. I have a friend with a strong family history of uterine and breast cancer who is screened every 6 months with serum tumor markers.
I too found the article AngelF referenced in a PubMed search to be very interesting.
I know that she and her husband are currently trying to get pregnant, so I will be sure to discuss this topic and article with her. Hopefully she and her doctors can discuss a plan for continued screening in pregnancy BEFORE she gets pregnant. If the weigh the pro-cons together, hopefully they can avoid any potential false-positive scares without being prepared ahead of time.
Thanks again.