Colon Cancer Metastasis to the Brain
Some cases of colon cancer can metastasize (spread) to other areas of the body, including the brain. This occurs when cancerous cells break away from the tumor in the colon, travel to the brain through the bloodstream or lymphatic system and then begin multiplying within the brain.
It’s relatively rare for colon cancer to metastasize to the brain. In fact, less than 3% of patients with colorectal cancer experience brain metastases (it’s much more common for colon cancer to metastasize to the liver, since the two organs are connected by a large blood vessel). Despite that small percentage, colon cancer is still one of the types of cancer most likely to cause brain metastases (other common types include breast cancer, kidney cancer, lung cancer and melanoma).
People often mistakenly assume that someone with brain metastases has brain cancer. That’s actually not the case. When cancer metastasizes from one area of the body to another, the resulting tumors are still made up of cancerous cells from the original body part. So, when colon cancer metastasizes to the brain, the tumors that develop in the brain will still consist of cancerous colon cells, not cancerous brain cells.
When colon cancer metastasizes to the brain, the resulting tumors can exert pressure on the brain tissue, causing symptoms such as:
- Weakness or numbness on one side of the body
- Memory loss
- Personality changes
Symptoms will vary depending on a number of factors, such as where the tumors are located, how big the tumors are and how quickly the tumors are growing.
If a physician suspects that colon cancer has metastasized to the brain, he or she may attempt to confirm or rule out the diagnosis by performing:
- A neurological examination – This may include tests for balance, coordination, reflexes, vision, hearing and strength.
- Imaging tests – Some common imaging tests include computed tomography (CT) scans, magnetic resonance imaging (MRI) scans and positron emission tomography (PET) scans.
- A biopsy – After removing a sample of abnormal brain tissue, the physician will send it to a pathologist, who will examine it under a microscope to determine whether it’s malignant (cancerous) or benign (noncancerous). The pathologist will also need to determine whether the tumor is a primary tumor or a metastatic tumor; more specifically, whether the cells are from the brain, which would indicate brain cancer, or from the colon, which would indicate metastatic colon cancer.
Once colon cancer metastasizes to the brain or another distant body part, it’s considered to be Stage 4 (advanced) and may be treated using a combination of:
- Surgery – If a patient’s brain metastases are accessible, surgery may be used to remove as much of them as possible.
- Radiation therapy – Whole-brain radiation and stereotactic radiosurgery can each be used to kill the cancerous cells in brain metastases. As its name suggests, whole-brain radiation involves applying radiation to the entire brain; this often requires 10 to 15 sessions over the course of two to three weeks. Stereotactic radiosurgery, on the other hand, delivers precisely targeted radiation and can often be completed in one session. While the individual radiation beams used in stereotactic radiosurgery aren’t especially powerful, the location where all of the beams come together receives a strong dose of radiation.
- Chemotherapy – Chemotherapy can be used to kill cells that are rapidly growing throughout the body, including cancerous cells.
- Targeted therapy – Targeted drug treatments block abnormalities found within cancer cells, thereby killing the cells.
- Immunotherapy – Unlike other types of treatment that directly attack the cancer, immunotherapy involves strengthening the body’s immune system so that it’s better equipped to destroy the cancer on its own.
- Medication – Certain medications can be used to relieve the symptoms caused by brain metastases. Corticosteroids, for instance, can be used to reduce swelling in the brain, which can in turn minimize any resulting symptoms. Patients experiencing seizures may also benefit from taking anti-seizure medication.
A physician will prescribe a course of treatment that’s customized to the patient’s specific condition and lifestyle. In many cases, the goal of treatment for colon cancer that’s metastasized to the brain is to slow the growth of the tumors, ease the patient’s symptoms and extend the patient’s life.
Notably, because brain metastases can often impact cognitive abilities, vision, speech and motor skills, rehabilitation is often a necessary component of the treatment process. Depending on the patient’s condition, a physician may recommend physical therapy, occupational therapy or speech therapy to help the patient regain these functions.
For more information
To learn more about colon cancer metastasis to the brain, turn to the experts at Moffitt Cancer Center. The specialists in our Gastrointestinal Oncology Program have experience treating all stages of colon cancer, including colon cancer that’s metastasized to the brain. Our team includes medical oncologists, radiation oncologists, surgeons, pathologists and supportive care specialists, all of whom work together to provide the individualized treatment experience that Moffitt has come to be known for. Thanks to our robust clinical trials program, patients can receive therapies that aren’t yet widely available in other settings, all while under the supervision of our knowledgeable oncology team.
Medically Reviewed by Dr. Peter Forsyth, Chair, Department of Neuro-Oncology
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