The Colon Club

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.

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

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!

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.

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.

I have a similar problem ATM. A MRI in December showed a 5mm thing in my liver that the radiologist judged to be a cyst. Looking at my most recent CT scans, the thing is clearly visible (once you know it's there), but in the CT it's just a slightly darker spot in one slice. In the MRI you can make out a high-intensity center surrounded by a dark shell, whereas the rest of the liver looks greyish with whitish vasculature.

Anyhow, the cyst is visible in my CT scans back to late last summer, but not visible before that. So it's safe to say the blob is either new or growing. Meanwhile the upward trend of my CEA continues with a new high measurement in January.

The MRI also notes a smaller cyst in my kidney, but my amateur eyes have trouble seeing it. That is a much less likely location for mets, anyhow.

There are some open access papers talking about how to distinguish between benign and metastatic liver cysts on MRI.
"Differentiating metastatic mucinous colorectal adenocarcinomas from simple cysts of the liver using contrast-enhanced and diffusion-weighted MRI" is not hard to read and has lots of picture examples.

"Colorectal liver metastases: radiopathological correlation" is harder to read but has lots of pictures of different types of scans compared to pictures of actual resected tumors.

My impression is that on an MRI an expert can have some clues about whether a small cyst is a met or benign, but the CT can only check for the presence and maybe the size of the thing. Another option is ultrasound. Much easier to get.

I may have replied to this in the past, but I'll do a brief response. I am a radiologist, but this is NOT medical advice. I saw some information in the other posts that I wanted to comment on.

CT has better spatial resolution than MRI, but MRI has better contrast resolution. They have different pros/cons. CT slices can be as thin as 0.625 mm. MR slices tend to be significantly bigger (5 mm for example) -- depending on the protocol that is in use, which varies from place to place. But "spots" will show up as bright on the MRI on certain sequences, so they can be easier to see. Regarding "regular" CT vs "multiphase" CT --> it really depends what is meant by "regular." If it is without contrast, mets are very difficult to see. CT for CRC mets should be done with contrast, but sometimes people cannot have contrast for other reasons. Multiphase CT means you do multiple CT exams in different phases of where the contrast is in your body (no contrast, contrast in the arteries, contrast in the portal veins, contrast in the systemic veins, delayed phases, etc) -- and this also depends on the protocol being used by your hospital or imaging center. Seeing the liver in different phases makes it easier to see "spots." Ultrasound is less sensitive than CT and MRI, so this is not typically recommended in the US, but may be recommended in other healthcare settings. Ultrasound is less expensive and has no radiation. PET/CT requires that a lesion be at least 8mm to be detected (sometimes smaller spots can be detected if they are very active).

If a "spot" is less than 8-10mm, it can be difficult to tell on CT if it contains water only (a cyst). The phrase "too small to characterize" is often used. If it's bigger than 10mm, looks like water (this is determine by density on CT and signal on MRI), and does not enhance (meaning the contrast gets into it and it gets brighter), it is called a cyst (a benign finding). Anything that does not meet the criteria for water or that enhances is looked at much more carefully --> maybe it is a complex cyst, a benign liver tumor, or cancer. There are many enhancing tumors in the liver that are not cancer, and they have certain patterns on CT and MRI (especially the latter) that a radiologist can evaluate. But if your CT is for colon cancer surveillance, the radiologist is looking with special attention to where CRC mets go (liver, lungs, brain, peritoneum, ovaries, bones, etc). Fatty infiltration looks different than a "spot" - it is shaped differently and not as well defined. It looks different from typical metastases. Small mets will be indistinguishable from benign lesions, which is why surveillance and looking at change over time is necessary, as well as following CEA levels and any other markers that are helpful for that cancer.

I hope everyone's spots stay small and benign!

menreeq wrote:I may have replied to this in the past, but I'll do a brief response. I am a radiologist, but this is NOT medical advice. I saw some information in the other posts that I wanted to comment on.

CT has better spatial resolution than MRI, but MRI has better contrast resolution. They have different pros/cons. CT slices can be as thin as 0.625 mm. MR slices tend to be significantly bigger (5 mm for example) -- depending on the protocol that is in use, which varies from place to place. But "spots" will show up as bright on the MRI on certain sequences, so they can be easier to see. Regarding "regular" CT vs "multiphase" CT --> it really depends what is meant by "regular." If it is without contrast, mets are very difficult to see. CT for CRC mets should be done with contrast, but sometimes people cannot have contrast for other reasons. Multiphase CT means you do multiple CT exams in different phases of where the contrast is in your body (no contrast, contrast in the arteries, contrast in the portal veins, contrast in the systemic veins, delayed phases, etc) -- and this also depends on the protocol being used by your hospital or imaging center. Seeing the liver in different phases makes it easier to see "spots." Ultrasound is less sensitive than CT and MRI, so this is not typically recommended in the US, but may be recommended in other healthcare settings. Ultrasound is less expensive and has no radiation. PET/CT requires that a lesion be at least 8mm to be detected (sometimes smaller spots can be detected if they are very active).

If a "spot" is less than 8-10mm, it can be difficult to tell on CT if it contains water only (a cyst). The phrase "too small to characterize" is often used. If it's bigger than 10mm, looks like water (this is determine by density on CT and signal on MRI), and does not enhance (meaning the contrast gets into it and it gets brighter), it is called a cyst (a benign finding). Anything that does not meet the criteria for water or that enhances is looked at much more carefully --> maybe it is a complex cyst, a benign liver tumor, or cancer. There are many enhancing tumors in the liver that are not cancer, and they have certain patterns on CT and MRI (especially the latter) that a radiologist can evaluate. But if your CT is for colon cancer surveillance, the radiologist is looking with special attention to where CRC mets go (liver, lungs, brain, peritoneum, ovaries, bones, etc). Fatty infiltration looks different than a "spot" - it is shaped differently and not as well defined. It looks different from typical metastases. Small mets will be indistinguishable from benign lesions, which is why surveillance and looking at change over time is necessary, as well as following CEA levels and any other markers that are helpful for that cancer.

I hope everyone's spots stay small and benign!

This was super insightful- thank you so much sharing!!!

Thanks for all the detailed replies. Turns out I have the BRAF V600E mutation so rather than waiting till post chemo (just started cycle 4 Capox) then my oncologist has scheduled a CT with contrast for tomorrow. If anything concerning re small spots in the liver then will have MRI to follow. My CEA has only risen slightly since last read a few weeks back now 3.5 so still normal and oncologist not concerned about it.

My CT recent scan during final CAPOX cycle in Feb showed NED with the v small liver spots unchanged (this radiologist - rather than classifying them as cysts or fatty deposition - stated that differential diagnosis of these spots included cysts and hemangiomas). However, my most recent CEA has climbed again to 4.6 to continue the trend over the three months of chemo. This has prompted the oncologist to act as although it often rises during chemo the concern is that time to recurrence and risk of recurrence is higher with the BRAF V600E mutation and CT scans can often be clear for a number of months after CEA starts to rise before a met shows on the scan (if that is what is causing the CEA to increase). Thus my next CT scan has been brought forward from Sep to Jun and colonoscopy brought forward too. Another option we discussed was doing a PET scan now incase it shows something not picked up by the CT but in the end decided to go with the earlier CT and colonoscopy route. I’m pretty relaxed about it as think chemo is the most likely reason for the rise and in absolute terms the level isn’t that high albeit it is trending up consistently.

Static500 wrote:My CT recent scan during final CAPOX cycle in Feb showed NED with the v small liver spots unchanged (this radiologist - rather than classifying them as cysts or fatty deposition - stated that differential diagnosis of these spots included cysts and hemangiomas). However, my most recent CEA has climbed again to 4.6 to continue the trend over the three months of chemo. This has prompted the oncologist to act as although it often rises during chemo the concern is that time to recurrence and risk of recurrence is higher with the BRAF V600E mutation and CT scans can often be clear for a number of months after CEA starts to rise before a met shows on the scan (if that is what is causing the CEA to increase). Thus my next CT scan has been brought forward from Sep to Jun and colonoscopy brought forward too. Another option we discussed was doing a PET scan now incase it shows something not picked up by the CT but in the end decided to go with the earlier CT and colonoscopy route. I’m pretty relaxed about it as think chemo is the most likely reason for the rise and in absolute terms the level isn’t that high albeit it is trending up consistently.

Yeap, I think if they are small PET might not pick them up (it seems PET is not reliable for lesions under 8mm)

I understand MRI might be best to diagnose liver lesions and has the advantage of not being relatively harmless (no radiation). Have you considered it?

Good luck

I_will_fight wrote:

Static500 wrote:My CT recent scan during final CAPOX cycle in Feb showed NED with the v small liver spots unchanged (this radiologist - rather than classifying them as cysts or fatty deposition - stated that differential diagnosis of these spots included cysts and hemangiomas). However, my most recent CEA has climbed again to 4.6 to continue the trend over the three months of chemo. This has prompted the oncologist to act as although it often rises during chemo the concern is that time to recurrence and risk of recurrence is higher with the BRAF V600E mutation and CT scans can often be clear for a number of months after CEA starts to rise before a met shows on the scan (if that is what is causing the CEA to increase). Thus my next CT scan has been brought forward from Sep to Jun and colonoscopy brought forward too. Another option we discussed was doing a PET scan now incase it shows something not picked up by the CT but in the end decided to go with the earlier CT and colonoscopy route. I’m pretty relaxed about it as think chemo is the most likely reason for the rise and in absolute terms the level isn’t that high albeit it is trending up consistently.

Yeap, I think if they are small PET might not pick them up (it seems PET is not reliable for lesions under 8mm)

I understand MRI might be best to diagnose liver lesions and has the advantage of not being relatively harmless (no radiation). Have you considered it?

Good luck

I would support the above... my liver has never imaged well on CT. There was something funny happening on a PET-CT, and my surgeon ordered an MRI Liver. This is a detailed liver study which is different to a regular abdominal MRI. This picked up a 14mm lesion hiding behind my right hepatic vein, which was then able to be resected. We then added MRI Liver as my surveillance scan for 6 months.

As mentioned one benefit of these is no radiation - main downside is they are expensive and time-consuming (1-1.5 hours per scan). I live in a “free” healthcare country and even they will only pay for one of these per year!

Thanks both. Yes the potential inability of even a PET-CT to identify tiny liver lesions - and that these few spots on my liver have remained unchanged - was one of the factors we discussed when deciding on the imaging strategy. I guess in theory they could have grown from the pre-surgery scan until chemo started and then shrunk back to roughly the same size as pre-scan during chemo hence appearing unchanged but think this is a v low probability scenario. My oncologist did say a while ago that a liver MRI would be used if there were any suspicious spots on my liver but as these are unchanged then did not suggest it on our most recent call. They did not do a liver MRI pre surgery either when originally diagnosed and spots were visible on the pre surgery scan.

Have not discussed the exact scheduling yet but am presuming would make sense to do my next CEA a couple of weeks before the CT scan as if it has continued to rise materially post chemo then could warrant going straight to a PET-CT rather than doing a CT first. And if it has reverted back to pre chemo level below 2 then may not even be a need to have the scan in June although I get the sense my oncologist wants to monitor me a bit more closely than standard protocol given my BRAF V600E mutation.

jts wrote:I have a similar problem ATM. A MRI in December showed a 5mm thing in my liver that the radiologist judged to be a cyst. Looking at my most recent CT scans, the thing is clearly visible (once you know it's there), but in the CT it's just a slightly darker spot in one slice. In the MRI you can make out a high-intensity center surrounded by a dark shell, whereas the rest of the liver looks greyish with whitish vasculature.

Anyhow, the cyst is visible in my CT scans back to late last summer, but not visible before that. So it's safe to say the blob is either new or growing. Meanwhile the upward trend of my CEA continues with a new high measurement in January.

The MRI also notes a smaller cyst in my kidney, but my amateur eyes have trouble seeing it. That is a much less likely location for mets, anyhow.

There are some open access papers talking about how to distinguish between benign and metastatic liver cysts on MRI.
"Differentiating metastatic mucinous colorectal adenocarcinomas from simple cysts of the liver using contrast-enhanced and diffusion-weighted MRI" is not hard to read and has lots of picture examples.

"Colorectal liver metastases: radiopathological correlation" is harder to read but has lots of pictures of different types of scans compared to pictures of actual resected tumors.

My impression is that on an MRI an expert can have some clues about whether a small cyst is a met or benign, but the CT can only check for the presence and maybe the size of the thing. Another option is ultrasound. Much easier to get.

Interesting. I know cea rises for many different reasons. However, was your increase in CEA due to a liver cyst?