Words to know: Colorectal cancer
- Adenocarcinoma
- The most common type of colorectal cancer. It starts in cells that line the bowel and make mucus.
- Adjuvant therapy
- Treatment given after surgery to lower the chance the cancer comes back.
- Neoadjuvant therapy
- Treatment given before surgery, often to shrink the tumor.
- Total neoadjuvant therapy (TNT)
- Giving all planned chemotherapy and radiation before surgery, used mostly for rectal cancer.
- Watch-and-wait
- Close follow-up instead of surgery when a rectal tumor seems completely gone after treatment. Also called non-operative management.
- Clinical complete response
- When exams, scopes, and scans can no longer find any tumor after treatment.
- Polyp
- A small growth on the inner lining of the bowel. Some polyps can turn into cancer over time.
- Colostomy
- An opening made on the belly so stool can leave the body into a bag. It can be temporary or permanent.
- Ileostomy
- Like a colostomy, but made from the small intestine. It is often temporary to let the bowel heal after rectal surgery.
- Total mesorectal excision (TME)
- The standard surgery for rectal cancer. It removes the rectum and the fatty tissue and lymph nodes around it.
- Lymph nodes
- Small bean-shaped glands that help fight infection. Cancer can spread to them.
- Metastatic
- Cancer that has spread from where it started to other parts of the body, such as the liver or lungs.
- Metastasectomy
- Surgery to remove cancer that has spread to another organ, such as the liver or lung.
- Mismatch repair (MMR)
- The system cells use to fix mistakes in their DNA. dMMR means this system is broken; pMMR means it works.
- Microsatellite instability (MSI)
- A sign on tumor testing that the DNA repair system is broken. MSI-high (MSI-H) is closely linked to dMMR.
- Lynch syndrome
- An inherited condition that raises the risk of colorectal, uterine, and some other cancers.
- RAS
- A group of genes (KRAS and NRAS) that act as a growth switch. RAS changes affect which targeted drugs will work.
- BRAF
- A gene that can be changed in some colorectal cancers. The V600E change has its own targeted treatment.
- HER2
- A growth protein. Some colorectal cancers have too much of it and can be treated with HER2-targeted drugs.
- CEA
- Carcinoembryonic antigen, a protein in the blood that can go up with some colorectal cancers. It is used to track the cancer.
- ctDNA
- Circulating tumor DNA, tiny pieces of tumor DNA in the blood that can be measured with a blood test.
- Immunotherapy
- Medicine that helps your immune system find and attack cancer cells.
- Targeted therapy
- Medicine aimed at a specific gene change or protein that helps the cancer grow.
- Neuropathy
- Nerve damage that causes numbness, tingling, or pain, often in the hands and feet.
- Palliative care
- Extra care focused on easing symptoms and stress. It can be given at any stage, along with cancer treatment.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.