When people hear “tumour size,” they assume it’s the main variable. Bigger means worse. Smaller means better. End of discussion.
That’s how we’re trained to think — because size is measurable, clean, and easy to compare.
But in metastatic colon cancer, especially when the disease is liver-dominant, size is only one part of the risk equation. Sometimes it isn’t even the most important part.
What shapes mortality more reliably is a combination of:
- where the tumours are located
- how much of the liver they occupy (overall burden)
- whether they interfere with the liver’s plumbing (bile ducts and blood flow)
- and whether liver function markers begin to shift
In other words: the liver doesn’t fail because a single lesion hits a magic number. It fails when enough of the liver becomes unusable or obstructed, leaving the organ unable to do its job.
Why I Went Looking for This Answer
James Van Der Beek’s recent passing was a jolt. Not because it gave me a new fear of death, but because it sharpened a question I’ve been carrying quietly: How do people actually die of colon cancer?
When you live inside scans and biomarkers, you start to realize that “stage” is not a storyline. It’s a label. What matters is the mechanism — what fails, what spreads, what accelerates, what stays contained.
It pushed me to understand the practical, clinical reality: If tumours stay localized to the liver, the end of the story often looks very different than if the cancer spreads to lungs, bone, peritoneum, or multiple organs.
And in my case, the situation is complicated: most lesions have been described as stable, while one keeps growing. That pattern raises a different set of questions than “everything is exploding.”
Understanding those differences doesn’t make anything easy. But it does take some of the power away from vague fear.
Why Placement Can Matter More Than Size
The liver isn’t just a chunk of tissue. It’s an engineered system. It has critical structures that make it function:
- Bile ducts that drain bile out of the liver
- Blood vessels that bring blood in and carry it out
- Functional reserve — the amount of healthy liver still doing the work
A tumour can be relatively modest in diameter but dangerous if it sits in the wrong place.
If a lesion is located near major bile ducts or central vascular structures, it can cause disproportionate consequences:
- reduced bile drainage
- rising bilirubin
- infections related to obstruction
- decreased ability to metabolize medications
- higher bleeding risk as the liver struggles to produce clotting factors
That isn’t drama. That’s mechanics.
By contrast, a lesion can be larger and still less immediately threatening if it’s located in the periphery and the rest of the liver remains functional and unobstructed.
That doesn’t mean “safe.” It means the failure mode is different.
The Trap of Asking “How Big Is It?”
This is the question everyone asks first — and it makes sense because it feels like control.
But the more important question is: How much functional liver remains?
One large lesion isn’t necessarily worse than multiple smaller ones scattered across both lobes. Liver failure risk rises when the disease becomes diffuse enough that healthy tissue and drainage pathways are squeezed out.
Clinicians often describe this as “tumour burden” — not just the diameter of one lesion, but the total percentage of the liver involved and whether key pathways are compromised.
Mixed Behaviour: When One Lesion Moves, and Others Don’t
This is the part that keeps my mind busy.
When multiple lesions remain stable, but one keeps growing, it suggests one of two things:
- that one lesion has slightly different biology (heterogeneity), or
- that systemic therapy is applying pressure unevenly
Either way, it changes the conversation. It becomes less about “the drug is working” or “the drug is failing,” and more about where control exists and where it doesn’t.
That’s also why local-control discussions enter the picture: if most of the disease is being held and one spot is misbehaving, the question becomes whether you can control the outlier without throwing away the whole strategy.
What Predicts the Typical Endpoint More Than Size
When clinicians worry that the liver is becoming the limiting factor, they watch for signs that the liver is losing reserve or becoming blocked.
The big ones are not mysterious:
- Bilirubin rising (bile flow and processing)
- INR / PT worsening (clotting factor production)
- Albumin falling (synthetic function and reserve)
- imaging evidence of biliary dilation (blocked drainage)
- imaging evidence of vascular compromise (flow problems)
- increasing fluid issues (often a sign reserve is thinning)
Those signals predict where things are headed far more reliably than “the lesion grew by 0.9 cm.”
Because what ends life in liver-dominant disease isn’t the number on a ruler. It’s the loss of function — and the complications that follow that loss.
One more reassuring note: my platelet trend is stable. My CBC trend shows platelets staying in the normal range (roughly 198–252) across multiple dates from mid-November through early February. In liver-dominant disease, a falling platelet trend can sometimes be an early hint that portal pressure is rising or liver reserve is being stressed. That isn’t what my numbers are doing right now. The scan may show one lesion pushing, but the bloodwork doesn’t show my liver “system” bending with it yet.
The Quiet Reality: Mortality Is Often a Plumbing Problem
A person with liver-dominant metastatic disease doesn’t typically reach the end because one tumour becomes “huge.” They reach the end when:
- drainage and flow become impaired
- liver function deteriorates
- infections become more frequent or harder to clear
- the body’s ability to tolerate treatment shrinks
- and options narrow
Size matters, but placement determines leverage — whether the tumours are pushing on systems that can trigger earlier complications.
When Metastasis Moves Beyond the Liver
This is the line I’m trying to stay on the right side of.
If the cancer spreads beyond the liver into multiple organs, the situation changes. Not because hope vanishes, but because the disease becomes less contained and more chaotic. More organs involved usually means:
- fewer opportunities for local control
- more pathways for complications
- faster narrowing of treatment options
- and, often, a more hurried decline
That’s not fatalism. It’s the basic difference between fighting a contained geography and fighting a system-wide spread.
It’s why “no extrahepatic disease” is never a throwaway line in a radiology report. It’s a structural fact.
The Most Grounded Conclusion I Can Hold
Size matters. It’s part of the story.
But placement is often what changes the meaning of size.
A peripheral lesion growing is a problem — but it’s not the same problem as a central lesion that threatens bile flow or blood supply. A liver full of scattered lesions is a different risk than one dominant lesion with everything else stable. And none of those realities can be reduced to one number without losing the plot.
Cancer isn’t only biology.
It’s geometry.
Where the lesion sits determines what it can disrupt.
How much space it takes determines what the body can still do.
And mortality, more often than most people realize, is decided by function — not fear.