Colorectal Cancer Metastatic
Metastatic colorectal cancer occurs when cancer that starts in the colon or rectum spreads to other parts of the body, most commonly the liver and lungs. While this advanced stage presents serious challenges, new treatments and approaches are helping patients live longer and with better quality of life.
Table of contents
- What is metastatic colorectal cancer?
- Where and how does the cancer spread?
- Symptoms of metastatic colorectal cancer
- What causes metastatic or recurrent colorectal cancer?
- How is it diagnosed?
- Treatment options
- Understanding prognosis and survival
What is metastatic colorectal cancer?
Metastatic colorectal cancer, also called stage 4 or advanced colorectal cancer, is cancer that has spread from the colon or rectum to other parts of the body[1]. This is different from cancer that starts in another organ and moves to the colon. Even when colorectal cancer spreads to distant organs like the liver or lungs, it is still considered colorectal cancer because that is where it originally started[3].
Up to half of people diagnosed with colon cancer eventually develop cancer in other parts of the body[1]. About 23% of people are diagnosed with colorectal cancer after it has already spread to distant sites[7]. When the original cancer is removed before it spreads, the chances of it returning are lower[3].
Metastatic colorectal cancer remains a serious disease with a 5-year survival rate of approximately 14%[2]. However, new research and treatments are improving outcomes, and for some patients with cancer spread to limited sites, long-term control or even cure may be possible[11].
Where and how does the cancer spread?
The most common locations where colorectal cancer spreads include the liver, lungs, abdominal cavity, and distant lymph nodes (small organs that are part of the immune system)[1]. The liver is the most frequent site, followed by the lungs[3]. Less commonly, the cancer can spread to bones, the brain, or the tissue lining the abdominal wall called the peritoneum[4].
Stage 4 colon cancer is divided into three categories based on how far the cancer has spread. In stage IVA, cancer has spread to one distant organ or area. In stage IVB, it has spread to more than one distant organ or area. Stage IVC means the cancer has spread to the peritoneum and may have also spread to distant organs[4].
Research has shown that colorectal cancer may spread much earlier in the disease process than previously thought. Studies suggest that cancer cells can break away from the original tumor and travel through the blood or lymph system to distant locations long before the original tumor can be detected by screening tests[5]. In many cases, the genetic changes that allow cancer to spread are already present throughout the primary tumor early in its development[5].
Colorectal cancer often spreads first to nearby lymph nodes. From there, it may continue spreading to more distant parts of the body[6].
Symptoms of metastatic colorectal cancer
Colon cancer doesn’t always cause symptoms, even when it has progressed to stage 4[1]. Some people don’t have any symptoms for some time[3]. When symptoms do occur in metastatic colon cancer, they can be similar to colon cancer that hasn’t yet spread outside the colon.
Common general symptoms may include:
- A change in bowel habits, such as more frequent diarrhea, constipation, narrow stools, or changes in stool shape[1]
- Blood in the stool, or stools that look like black tar[3]
- Pain in the belly, especially gas pains, cramps, bloating, or a feeling of fullness[3]
- A feeling that the bowel doesn’t empty all the way during a bowel movement[1]
- Rectal bleeding[1]
- Feeling full soon after eating or a lump in the belly button area[1]
- Unexplained weight loss and loss of appetite[3]
- Constant tiredness, also called fatigue[3]
- Iron deficiency anemia (low red blood cell count), which can cause tiredness, weakness, and changes in skin color[1]
- Pain in the back, buttocks, or legs[1]
Other symptoms depend on where the cancer has spread. If cancer spreads to the liver, it may cause pain in the upper right part of the belly, yellow skin and eyes (a condition called jaundice), or belly swelling[3]. When it spreads to the lungs, it can cause shortness of breath, persistent cough (especially coughing up blood), or chest pain[3]. If it spreads to the brain, symptoms can include headaches, seizures, dizziness, confusion, or vision problems[3]. Cancer that spreads to bones may cause bone pain[6].
What causes metastatic or recurrent colorectal cancer?
Doctors don’t know the exact cause of metastatic or recurrent colorectal cancer[3]. Sometimes cancer cells are too small to be found by tests. These tiny cells may continue to grow and show up later as metastatic cancer, even years after treatment[3].
Colon and rectal cancers can return months or years after treatment. This is called recurrent cancer[3]. Recurrent colorectal cancer occurs when the cancer begins to grow again after treatment[6].
How is it diagnosed?
Metastatic colon cancer is diagnosed through a combination of physical examination and several types of tests[8].
Imaging tests look for areas of cancer inside the body. CT scans (computed tomography) and MRI scans (magnetic resonance imaging) are the main imaging tests used to detect colon cancer and determine how far it has spread[8]. A PET scan (positron emission tomography) may also be helpful to decide if surgery is an option for cancer that has spread outside the colon[8]. Brain CT scans or MRIs can help look into symptoms such as confusion, numbness, vision problems, or headaches[3]. A bone scan helps doctors find out if cancer cells have spread to the bones[3].
A biopsy is a procedure to remove a sample of tissue for testing in a lab. For colon cancer, the tissue sample is often collected during a colonoscopy (a procedure that lets your doctor see inside your intestine)[3]. Sometimes surgery is needed to get the tissue sample. If imaging tests show a mass in the liver or lung, a liver or lung biopsy might be done[3]. Tests performed on the cancer cells can show whether the cells are cancerous, what type of cancer it is, and provide information about gene changes that can guide treatment decisions[8].
Blood tests may include a carcinoembryonic antigen test, or CEA. This measures a protein made by some colon cancer cells and can help find out if cancer has returned[3]. High levels of CEA can indicate the presence or progression of colon cancer, especially in advanced stages[8].
Molecular and genetic testing examines the cancer cells in a lab to look for specific gene changes that affect how the cancer grows and responds to treatment[8]. These tests help doctors choose the best treatment, as some medicines only work for certain gene changes[8].
Treatment options
Treatment for metastatic colorectal cancer is based on many factors, including the location of the cancer, your overall health, and what matters to you[3]. Stage 4 colon cancer typically requires complex treatment strategies to manage symptoms and improve quality of life[1]. While there is no cure for most cases of metastatic colorectal cancer, treatment can keep it under control, relieve symptoms, and give you a good quality of life[7]. For a small number of people with cancer spread to limited sites, cure might be possible if surgeons can completely remove the cancer from both the bowel and the other affected organ[7].
The main treatments include:
Surgery may be an option in some cases[3]. For select patients with disease limited to the liver, options may include removal of liver tumors or even liver transplants[11].
Chemotherapy uses chemicals to kill fast-growing cancer cells in your body[7]. It is one of the main treatments for metastatic colorectal cancer[3]. If cancer has spread to the liver, some hospitals offer hepatic artery infusion, which delivers chemotherapy directly into the liver[11].
Targeted therapy uses drugs or other substances to identify and attack specific types of cancer cells[7]. This is another main treatment option for metastatic colorectal cancer[3].
Immunotherapy may help your immune system attack and kill cancer cells[7]. This treatment approach is available for some patients with metastatic colorectal cancer[1].
Radiation therapy may also be used as part of treatment[1]. Advanced techniques like stereotactic body radiation therapy (SBRT) can precisely target tumors[11].
Other treatments for liver metastases may include thermal ablation (using heat to destroy tumors) and embolization (blocking blood supply to tumors)[3]. Some centers also offer newer techniques such as histotripsy, which uses sound waves to destroy tumors in the liver[11].
A clinical trial may be an option for you[3]. Clinical trials explore new treatments that are under investigation to confirm if they may work against metastatic colorectal cancer[7].
Your doctor will talk with you about your options and help you make decisions based on your individual situation[3]. Your care team will also likely suggest supportive care (also called palliative care) to help manage pain, depression, anxiety, and other physical and emotional challenges[7].
Understanding prognosis and survival
Metastatic colorectal cancer remains a serious disease. Despite increasing survival rates overall, metastatic colorectal cancer has a 5-year survival rate of approximately 14%[2].
However, outcomes can vary greatly depending on individual circumstances. Treatment can keep cancer under control for extended periods in many patients, and for some people with limited spread, long-term control is possible[7]. Current therapeutic strategies continue to evolve, and new treatments are changing the outlook for many people with metastatic colorectal cancer[11].
Your doctor can provide information about what your diagnosis means, what is likely to happen, and how treatment can help you[7]. Many people find that knowing more about their situation makes it easier to cope[7].
