Important points regarding those aspects of colon cancer about which the general public knows the least: Metastasis, Recurrence, and Follow-up.
Metastatic cancer is a stage wherein colon cancer cells have invaded tissues or organs that are far from the primary cancer location. Microscopically, these cancer cells that are found in other organs resemble the cancer cells of the primary tumor/cancer. They usually express the same molecular proteins as well as manifest the same chromosomal changes as the primary tissue.
Metastatic colon cancer can be treated. However, rather than cure, the main goal of treatment for metastatic colon cancer is the control of growth of colon cancer cells as well as relieving unwanted symptoms caused by the invasive tumor.
Metastasis can occur via three methods:
Direct Invasion– invasion of nearby tissues
Lymphatic Spread– cancer cells gain access to the lymphatic system
Hematogenous Spread– cancer cells enter the bloodstream and can lodge to different locations throughout the body
Distribution of Colon Cancer cells in the Body
When cancer forms a polyp, it eventually grows through the wall of the colon or rectum. Then, they begin to develop into the blood vessels (angiogenesis) as well as lymph vessels. The moment cancer cells gain access to the blood or the lymph vessels; they can go to nearby lymph nodes or even to other areas of the body, commonly the liver.
Typical Location of Metastases
The site of metastasis can vary in every type of tumor or cancer. Colorectal cancer often metastasizes to the liver, kidneys, the bone, lungs, lymph nodes and the brain. When the colon cancer is confined to one distant location that is the liver or lungs, cure or remission is possible. However, if multiple sites of metastasis are detected, treatment becomes even more complicated.
2.Recurrent Colon Cancer
Recurrent colon cancer is a condition that has recurred or returned after the treatment has been completed. It is important to note that cancer may not come back in the same location as previous cancer. It may even be seen in other parts of the body such as the lungs, the liver or both.
If cancer has returned to the same site, surgery followed by chemotherapy can at times help extend the life of the patient and may even provide a cure. However, if the cancer cells cannot be surgically removed, chemotherapy may be a good first treatment option.
If cancer returned at a distant site, the most common location is the liver. Surgery is not advised in most cases. Again, chemotherapy may be started to reduce the size of the cancer cells, which is later followed by surgery.
Finally, if cancer has become too widespread for surgical correction, chemotherapy, and targeted therapies may be helpful in the treatment. It would be wise to talk with your doctor or your health care team for the proper course of action.
3.Follow Up Treatment
Following the staging and diagnosis of colon cancer, re-staging may be done to evaluate the extent of cancer further. Also, during follow-ups, you will be required to undergo further lab testing or evaluations, check-ups, blood tests, scans (i.e. CT, PET, MRI, and ultrasound) and colonoscopies to check the response of cancer cells; whether they disappeared, shrunk, or remain the same. These tests may continue for several years and may become less and less frequent as the years pass and as your cancer becomes more stable, the need for the tests reduce accordingly.
Regular exams – these are done during routine check-ups with your doctor. A thorough physical examination is conducted to check if there is a recurrence.
Colonoscopy – Colonoscopy may be required even after the cancer treatment. Most doctors recommend regular colonoscopies for 6 to 12 months after surgery and every three years after that.
Blood Test – Routine blood tests are also done to detect the presence of carcinoembryonic antigen (CEA) and CA 19-9, which are tumor markers for colon cancer. Their levels in the blood may indicate the presence or absence of colon cancer.
CT scans – CT scans are recommended for patients who are expected to have cancer recurrence. Common areas assessed include the pelvis, chest, and the abdomen.