Bowel cancer treatment and side effects

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CT & Colonoscopy brought forward - big drop in Serum Ferritin

Hello everyone.

By way of a quick recap, husband was diagnosed Stage 3b in July last year (pT4a N1c (0/47) V1 Pn0 R0 M0). He finished 8 cycles of CAPOX 2 months ago. Throughout chemo his CEA rose from 3,4,5,7. No one ever seemed to mention this which I found odd as to me there was enough there to warrant further investigation. Fast forward to mid May and he had his first call with CNS back on the surgical team. She said it was great that his CEA after surgery had dropped from 12 to 3. It was at this point I said that it had crept up to 7 during chemo. She hastily shuffled her papers around, spotted this, and arranged a follow up CEA. My husband had been feeling tired in his legs again so asked if he could tag on a FBC to the CEA test. Just a couple examples of how important it is to be your own advocate!

We got the results a couple of days ago and whilst it is great that his CEA has dropped back down to 4, his Serum Ferritin has tanked to 20. For background, at diagnosis his Serum Ferritin was 5 and hb 90. He had two Iron infusions and the readings went up to 292 and 134 respectively just prior to surgery. They are now wanting to bring forward his CT and Colonoscopy (first annual ones were going to be in September). The motive seems to be that they are worried there is a bleed somewhere. This has really rattled us. His hb at the latest count is 126 so now looking slightly anaemic.

Has anyone had any issues with their Serum Ferritin at this stage? I'm guessing we're heading back to Iron Deficiency Anaemia. What's tricky is that I'm not sure they included Serum Ferritin in the bloods he had throughout chemo so we have no picture.

Thanks all. Just feeling so nervous all over again and worried the bastard is back. The CNS was saying they're being extra cautious and we shouldn't worry but when they want to bring everything forward it's hard not to!!


Hi @DFTP sorry you are so worried! I don’t know if positive stories from others help, but I found out my serum ferritin had dropped sharply (to 6 micro g/l) just after I had had a colonoscopy and CT earlier this year. Both exams were fine.
I had bloods done for a health issue unrelated to bowel cancer, and in my case it is likely that caused the drop in ferritin.


@Wegwe - I'll take positive stories all day long! thank you for responding so quickly. I guess I just wasn't expecting to go down the rabbit hole so soon. But, a lot of that is down to me so need to get my big girl pants on! At least they are being proactive I's taken them a while to get going though. Thanks again :x:


Hi @DFTP, I have had issues with low serum ferritin on and off for about four years. It is not routinely tested for and in fact my Hb is always normal! When the reason for my breathlessness wasn’t clear they tested for ferritin and found it was very low. I have needed three ferritin transfusions over time. In my case, and I am on permanent chemo, they are not worried, but we monitor the levels every three months or so. So no rhyme nor reason with me! Take care, Kim :x::x:


Hi @DFTP actually so have I since diagnosis and I dont think it is cancer related. Also think @kawa909 has had this issue too and he is NED etc. He has had lots of investigation too and he may be able to advise.

I get your worry. One of my red flags was low ferritin, which I assumed was the cancer....however now its still low and I have had a clear bowel and no internal bleeding. So my guess is that it may be that I always had low ferritin and it was just picked up and viewed as because of bowel cancer but actually was unrelated! So i take iron pills. Apparently diff bits of colon can be affected in terms of iron absorption too so may be to do with that. I'm like Kim in that my HB is fine and bloods all good, but the ferritin is low. :x:


@DFTP I was diagnosed stage 3 in July 2020, finished chemo in Dec 20, at which point my HB was fine. Fast forward to May last year and both ferratin and hb had tanked (think ferratin) was around 5 - was exhausted again and utterly triggered as anemia was my only real symptom on diagnosis. I had CT, colonoscopy, endoscopy and finally small bowel capsule endoscopy. They couldn't find anything wrong, and slowly very slowly and with the help of iron pills my HB recovered and my ferratin started creeping back up . Been off iron pills a few months now and HB was fine at last blood test and ferratin up to the very low end of normal. No doctor has been able to identify the cause but I've been thoroughly investigated and they aren't worried, and things now heading in right direction. 🤷🤷 I do hope that's the same for your husband. But I totally totally get how worrying and triggering it is! :x::x:


@Lirio345 @momentbymonent @louise28 - thank you all so much for responding. Sounds like this isn't as uncommon as I had thought. And you're right, it's hard to know what is 'normal' for him as serum ferritin isn't often part of a FBC. He's got an iron infusion booked for next week, colonoscopy week after and we await a booking for the CT. You're all so kind for taking the time to reply. thank you.


Hi @DFTP hope you're ok, what a worrying time for you. You have had some very helpful responses above, but just if it helps, I have recently had a rectal cancer diagnosis and my fit test was >200ug (should be <10ug) and my serum ferritin level was actually high at diagnosis. I think the cut off was 50 and I was 58. I know our stories are different but just wanted to relay to you that just because it's low again doesn't mean it's back, it could be a number of things. Thinking of you at this time, the waiting for tests and results is awful :x::x::x:


Hi @DFTP - as @louise28 mentioned I have had a lot of investigation into these issues and indeed there appears to be quite a few similarities in mine and your husband’s patient history to date. I was diagnosed stage 3 in Autumn 2020 with only symptom being IDA with serum ferritin 5 and Hb around 70-80. Also had gradually rising CEA during chemo which then fell back again afterwards, something that is not especially uncommon.

Since then I’ve remained disease free but serum ferritin has remained stubbornly low with most of the time it being below the minimum normal level, although my Hb has stayed around 120-130. Oncologist referred me to gastroenterologist and I’ve had various investigations such as small bowel capsule endoscopy and CT small bowel enterography but no explanation has yet been found for the low iron and no evidence of any bleeding. I recently had an iron infusion and have a follow up consultation in August to see what blood scores are after this infusion.

Gastroenterologist thinks may be an absorption issue but blood tests for things like coeliacs have been negative and nothing evident in any of the investigations that would indicate absorption problems. That said, I have read some research that suggests Omeprazole can reduce absorption of iron from food due to suppression of gastric acid secretion. I have been on Omeprazole since diagnosis so something I am going to raise at my consultation as a possible explanation. Good luck and hope your husband’s levels improve.


@kawa909 thank you very much for your reply. Marked similarities indeed! Seems you are both otherwise very fit and active and the real tell tale sign was frustrating performances on your runs. Your oncologist sounds very switched on and proactive. Sadly we've had quite the opposite experience this end and I dare say I'm going to have to keep right on top of this.
My husband has always complained of fatigue and I wonder if he simply runs low on iron as his default. The bleeding tumour of course tipped that over to dangerous levels. He also had tests prior to diagnosis which would probably rule out absorption issues.
Your comments on omeprazole were interesting. On cycle 2, my husband had the first of two severe stomach/chest one seemed to really want to spend the time getting to the bottom of it. Disappointing given the paramedics thought he was having a heart attack when they arrived he looked so awful! In response, oncologist increased his omep dose and told him to keep taking it which he did for 6 months. This might not constitue long term use but may be enough to mess with his serum ferritin if he tends to run low normally.
He has his ct this morning. Iron infusion Thursday and colonoscopy next Saturday. He's not been running since the beginning of chemo as his hand foot syndrome continues to plague him. On the one occasion we saw the onc face to face during chemo, I asked him to look at his feet and he simply said it wasn't necessary. He is doing nearly 200km a week on the bike so getting fitness levels back up but very much looking forward to some extra iorn!
I'll keep you posted. Thanks again.


@DFTP good luck with the CT results and hopefully the colonoscopy will be all clear too. For info if you’ve not tried it, it could be worth using some 25% urea cream on the feet and hands. I did start to get a bit of soreness in cycle 2 on the feet but once started using this cream it disappeared v quickly. The cream I used was flexitol 25% urea heel balm and was prescribed by my GP.


I have genetic Haemochromatis, which means I have iron overload, I was 439 at diagnosis and now 32, so I need to keep levels under 50 to avoid organ damage. Low iron has the same symptoms as high, weakness, tiredness and generally feeling unwell.