How easy is it to differentiate between benign liver spots and small mets on a CT scan?

[Static500]

Hi,

Currently undergoing 3m of CAPOX for stage IIIb ascending colon cancer following successful right sided hemicolectomy in October.

Just revisiting my (second) CT scan at diagnosis and for the lungs there were “no significant pulmonary nodules” whereas for the liver there were “sub centimetre simple hepatic cysts unchanged” and “focal low attenuation change adjacent to falciform ligament likely to represent focal fatty deposition”. Note that where it mentions unchanged / changed this is in relation to the first CT scan 7 weeks earlier (which only said inflammation in colon rather than diagnosing cancer).

Have read some research saying that it can be hard to differentiate between very small liver mets, cysts and fatty deposition so just wondering if anyone has had similar and know how certain they can be from the scan that the above findings are not infact v early mets? Oncologist has never raised it and I’m not worried about it, more of general interest having done some research and re read my reports. My CEA has also doubled from 1.6 to 3.2 in the 3 weeks between first and second CAPOX cycles but again these are normal type levels and can often increase during chemo so don’t think anything to be concerned about.

Thanks.

[GrouseMan]

Imaging is not a very good means of differentiating one thing from another and it really takes specialists with a good eye to even see the very subtle changes in between scans. One would like to have the same radiologist compare the scans and hopefully not be the first or last of the day that they do. It can be quite subjective when looking for a needle in a hay stack! The physics involved the imaging technology and resolution makes it a very difficult task. Additionally you probably don't want just any radiologist to do this. Best if one that is a specialist in abdominal cancers does it as they have a practiced eye verses someone that is a general radiologist looking for fractures or orthopedics issues.

Benign can really only be determined by a biopsy. Visually they probably look to be very much the same. My wife's liver mets looked like they had calcified according to her oncologist after Chemo, and he said probably dead. The one on her spleen disappeared completely. But the one that was in her peri cavity was very hard to visualize and wasn't really able to resolve very well until about 2 months before she passed away! That was the one that really did her in. It caused a blockage pinching off her colon basically from the outside and also pinched off one of her ureters' from her kidney to her bladder. The spots they thought might be mets in her lungs never ever changed and early on after initial chemo her oncologist believed they were not mets. So CT PET etc are only good for monitoring progress really.

Your CEA test are well within what is considered normal range. Doubling could be well within the range of testing error. And as some will indicate it can be raised by other factors. For many its not a good test at all. If it continues to climb out of the 5.0 range over several tests during the next 6 weeks then you might become concerned. My wife's started to go down and was in/near the normal range for quite some time but towards the end it started to climb back out again. So it was an indicator in her case of further growth when the chemo no longer was effective.

Good luck and try not to stress too much. If you haven't had a second opinion you might look into that. But still it appears your treatment is the standard one almost everyone starts out with in Stage IIIb. They don't seem to think there are any mets as far as I can see. If there where they would have staged you at stage IV.

GrouseMan

[Basil]

I was on my second to last scan before being released from surveillance and they found a small liver spot “not definitively seen” on my prior. My onc is not concerned about it (and my CEA is unchanged) but he ordered a MRI for my next scan, which was then eight months away. Says it’s probably a cyst. We’ll see in March!

[boxhill]

In my experience, a regular CT can't even pick up a 5 mm or so liver thing. It's too small. A multiphase CT may be able to. An MRI definitely can. But none of them, not even the MRI, can definitively say what they are and whether they are malignant. Only a biopsy can do that. And for a spot that small, it likely makes more sense to just remove it, depending on where it is in the liver. But even if it is on the surface of the liver, like my little mass, they are likely to say that it isn't worth even the small risk of liver injury unless it changes. Which is why my little liver thing is still there, but after 2+years of no change at all is considered to be something inert. So I am NED.

BTW, it is my understanding that a PET scan has the same size constraints as a CT scan, so if a mass is tiny it is not likely to pick it up.

Please note that everything I've said pertains strictly to VERY SMALL liver masses. Under a cm.

[I_will_fight]

Not sure if this helps, but I am asking myself the same question:

I have a 1cm nodule in my liver, the report mentioned it was more likely an hemoangioma.

This is what the CAT report says:

"In the periphery of liver's segment VIII a high-gain 10mm lesion in arterial-phase which becomes homogeneous in portal-phase, unchanged from previous CAT study, this suggest hemoangioma, but given the clinical context RMI is advised"

I was a bit nervous so I asked my surgeon and oncologist.

My surgeon (really great guy!) opened my last CT scan in his screen, and he patiently explained to me the following:

- The lesion has not changed in 6 months
- The lesion shows up with due to contrast when filled by artery blood.
- The lesion does not show up with Porta vein contrast.

Apparently this is not the way colon carcinoma mets show up in TACs, so they think it is not a MET, but being a cancer patient they still recommend an MRI which I will have in three weeks time.