What are metastases?

Every year tens of thousands of cancer patients in our country are told that their disease has spread. Often they have known for some time that they have cancer. Now what they feared has happened: more tumors have been found, in other places in the body. Cells from the original tumor have become detached, have moved elsewhere via the bloodstream or lymphatic system and have grown into new tumors there.

How are metastases detected?

If a patient is found to have cancer, he or she will be checked for metastases (‘screened’) after this diagnosis. Screening is sometimes done with blood tests for tumor markers. These are proteins in the blood that can also occur in healthy people. Tumor markers also show whether a treatment is working; if the value decreases, tumor activity decreases.

Furthermore, metastatic cancer can be detected with ‘imaging techniques’: an X-ray, ultrasound, MRI, CT scan or PET scan. Because these techniques are getting better, it is possible to discover smaller and smaller metastases. Metastases are now visible from about half a centimeter, but sometimes only when they are one centimeter in size. Unfortunately, metastases smaller than half a centimeter are still usually missed.

Sometimes keyhole surgery is needed to determine whether there are metastases. When diagnosed with breast cancer, there is always a sentinel node procedure to check whether the lymph nodes in the armpit are ‘clean’. If so, then the cancer has not spread.

Symptoms

What does a patient notice about metastases? Initially nothing. This is because they are still very small at first. But as they get bigger, patients may experience swollen glands, persistent cough, sudden severe headache, nausea, vomiting and reduced vision.

Larger metastases can press on the surrounding tissue and can grow in an organ, making it less effective. Complaints such as weight loss, loss of appetite or sudden severe fatigue also occur. The metastases cost a lot of energy and disrupt normal metabolism. Metastases in the liver can cause yellow skin, nausea and itching.

If they are in the bones, this causes pain that gets worse over time. The cancer cells make the bone weaker and weaker, so that it can even break. A metastasis in the spine can press on nerves. This can cause pain, muscle weakness, tingling or numbness in the limbs, as well as make a person temporarily unable to move or even develop a spinal cord injury.

Risk

The risk of metastasis differs per type of cancer. Bee breast cancer 25 percent of patients will have to deal with metastases. In colorectal cancer this is 50 percent. And 20 percent in prostate cancer.

Most tumors first spread to the lymph nodes closest to the tumor. These glands are located in the neck, abdominal cavity and groin, among other places. For breast cancer, these are the lymph nodes in the armpit. In a later phase, metastases can develop in other lymph nodes, organs, bones and tissues (such as muscles, nerves and connective tissue).