Colorectal liver metastases

Why colorectal cancer metastasizes to the liver

Blood from the colon and the rectum drains into the portal vein and reaches the liver before any other organ. That is why tumor cells that have separated from the primary lesion settle here first — earlier than in the lungs or the bones.

Metastases are called synchronous if they are found at the same time as the bowel tumor or shortly after it, and metachronous if they appear later, during follow-up. The sequence of treatment depends on this: in the first case it is decided what to operate on first — the bowel or the liver; in the second — whether surgery on the liver alone is enough.

Do liver metastases cause symptoms

Most often, no. The liver has a large reserve of tissue and has no pain receptors inside it, so small lesions do not hurt and do not change how a person feels. That is why most metastases are found not from complaints but on a scheduled CT during follow-up after bowel surgery — and this is the case where a missed check-up is costly.

Complaints appear when the lesions reach a considerable size or compress the bile ducts. The following are then possible:

• heaviness or dull pain under the right ribs;
• weight loss without an obvious cause and reduced appetite;
• yellowing of the skin and of the whites of the eyes, darkening of the urine — signs of impaired bile flow;
• increasing weakness and fatigue;
• an increase in the size of the abdomen.

None of these signs is specific to metastases — all of them occur in other conditions as well. Still, for a person who has already been treated for bowel cancer, any of them is a reason to have an examination earlier than scheduled rather than wait for the planned date.

Which examinations are needed before a decision

Surgery cannot be planned on an ultrasound report alone. What is needed:

• CT of the chest and abdomen with intravenous contrast — the basic study: the number, size and location of the lesions, the condition of the lungs and the lymph nodes.
• Contrast-enhanced MRI of the liver — more accurate than CT in detecting small lesions. It is often this study that changes the plan of the operation.
• PET-CT — in equivocal cases, when spread beyond the liver has to be ruled out.
• Carcinoembryonic antigen (CEA) — a marker for monitoring over time, not for making the diagnosis.
• Colonoscopy — assessment of the primary tumor or of the area of previous surgery.

A biopsy of a metastasis is not always needed: if colorectal cancer has already been confirmed histologically and the picture on CT or MRI is typical, it is often omitted. It is performed when the imaging is equivocal, the origin of the lesion is in doubt, or tissue is required for molecular testing.

When surgery is possible

The main question is not how many lesions there are in the liver, but whether enough healthy tissue will remain after they are removed. Resection is possible if:

• the remaining part of the liver is sufficient in volume and has its own blood supply, venous outflow and bile drainage;
• the lesions can be removed completely, within healthy tissue;
• the primary bowel tumor has already been removed or can be removed;
• there is no uncontrolled spread of the tumor beyond the liver;
• the patient’s general condition allows them to undergo the operation.

The number of lesions in itself is not a contraindication: it matters far more how they are located in relation to the large vessels and the bile ducts. The liver is able to regenerate, so removal of a considerable part of it is possible — provided that what remains is sufficient in volume and in function.

If surgery is not possible now

Some patients cannot be operated on straight away, but this is not always a final conclusion. In such cases the following are used:

• chemotherapy, to reduce the lesions to a size at which resection becomes possible;
• portal vein embolization, so that the healthy part of the liver increases in volume before a major resection;
• staged operations, when the liver is operated on in two stages with an interval between them.

After such treatment the examinations are repeated and the question of surgery is reconsidered. That is why a conclusion of “inoperable” made six months ago needs to be rechecked on up-to-date images.

How the operation is performed

The extent of the operation depends on the location of the lesions — from removal of individual areas (non-anatomical resection) to removal of a whole anatomical lobe of the liver.

When the location of the lesions and the required extent of resection allow it, the operation is performed laparoscopically — through several small incisions. The approach is chosen according to the size and location of the lesions, the extent of the operation and previous surgeries. This means less surgical trauma, less blood loss and faster recovery, which matters for patients who need to continue chemotherapy after the operation.

With synchronous metastases the bowel and the liver are sometimes operated on in one procedure and sometimes one after the other: the decision depends on the extent of both operations and on the patient’s condition.

For small lesions located deep in the liver, radiofrequency ablation is used — destruction of the lesion by heat without removing it. It is also used in addition to resection: some lesions are removed by the traditional technique (parenchyma-sparing or anatomical liver resections), while other lesions are treated with radiofrequency ablation.

Recovery after surgery

The length of the hospital stay depends on the extent of the operation and on the approach — after a laparoscopic operation it is usually shorter. Recovery follows the enhanced recovery after surgery protocol (ERAS): early mobilization, early return to eating, controlled pain relief.

Chemotherapy after surgery is started once the wound has healed and liver function tests have returned to normal. The exact timing is determined by the clinical oncologist together with the surgeon.

Follow-up after surgery

After resection, regular monitoring is needed: CT or MRI and the CEA level. The schedule is set by the doctor — it depends on the stage, the extent of the operation and the further treatment, and in the first years the checks are more frequent.

The appearance of a new lesion in the liver does not mean that the surgical options are exhausted: repeat resection or ablation is possible if the same conditions are met as for the first operation. Repeat operations are a separate area of my practice.

What to bring to the consultation

• the CT, MRI or PET-CT discs — the discs with the images themselves, not only the written reports;
• the histology report and, if available, the blocks and slides;
• discharge summaries of previous operations and chemotherapy regimens, with the number of cycles stated;
• recent blood tests, in particular liver function tests and CEA.

If some of the materials are missing, that is not a reason to postpone the consultation — some of the examinations can be done on site.

The consultation is free of charge. How it goes and how long it takes is described on the page “Oncologist Consultation”.