After a rectal cancer diagnosis, other tests might be needed to find out how far the cancer has spread. This is called staging. Knowing the stage of cancer is important because it helps your healthcare team create the most effective treatment plan.
Staging tests often include blood tests and imaging scans of the abdomen, pelvis and chest. These scans create pictures that show the location and the size of the rectal cancer. Sometimes imaging isn't enough, and surgery is needed to find out the stage of the cancer.
Staging terms
Rectal cancer is typically classified in five stages, but there is no stage 5 rectal cancer. The stages are 0, 1, 2, 3 and 4. Higher numbers mean more-advanced cancer. Earlier stages often mean the cancer is limited to the rectum, while later stages may involve spread to lymph nodes or distant organs.
To describe each stage in more detail, healthcare professionals commonly use the TNM system. The TNM system looks at three key factors:
- T. The size of the primary tumor.
- N. Whether the cancer has spread to nearby lymph nodes.
- M. Whether the cancer has spread to other parts of the body, called metastasis.
Staging can be complex, so if you're not sure what something means in your chart, ask your healthcare team to explain it in a way that makes sense to you.
Stage 0 rectal cancer
In stage 0, the earliest stage of rectal cancer, cancer cells are found only in the innermost layer of the rectum, called the mucosa. At this stage, the cells have not grown into deeper layers of the rectal wall. This stage also is referred to as carcinoma in situ.
If the cancerous area is small and accessible, doctors or other healthcare professionals may operate using a tool through the anus. This is called local excision. Local excision procedures include transanal excision (TAE) or transanal minimally invasive surgery (TAMIS). These procedures aim to completely remove the cancer while preserving rectal function. If the cancer is too large or poorly located for local excision, part of the rectum may need to be removed.
Stage 1 rectal cancer
In stage 1, the cancer has grown into the deeper layers of the rectal wall, but it has not spread to nearby lymph nodes or distant parts of the body. Because the cancer is still confined to the rectum, it is considered localized.
When stage 1 rectal cancer is found inside a polyp, local excision using transanal surgery may be the only treatment needed. If the cancer is considered high grade, meaning it's more likely to grow and spread quickly, a more extensive surgery may be recommended. Additional surgery or treatment also may be needed if the cancer is not completely removed or if the margins around the removed tissue are not clear of cancer cells.
In cases where the cancer is not in a polyp or is larger or deeper, a partial resection of the rectum may be performed. This procedure usually includes removal of nearby lymph nodes to check for microscopic spread.
Stage 2 rectal cancer
In stage 2 rectal cancer, the cancer has grown through the inner layers of the rectum and may have reached nearby tissues or organs. However, it has not spread to nearby lymph nodes or distant sites. Stage 2 rectal cancer is considered localized when it remains in the rectum It's considered regional if it has begun to involve nearby structures such as adjacent organs.
- Stage 2A. The cancer has reached the outer layers of the rectal wall but has not penetrated through them and has not spread to lymph nodes or distant organs.
- Stage 2B. The cancer has grown through the rectal wall into surrounding tissue but has not invaded nearby organs and has not spread to lymph nodes or distant sites.
- Stage 2C. The cancer has invaded nearby organs or structures such as the bladder, prostate, uterus or bone, but lymph nodes and distant organs are not affected.
Surgery to remove the affected portion of the rectum is often the first treatment. Procedures may include a low anterior resection (LAR) or abdominoperineal resection (APR) depending on the cancer's location and depth. Nearby lymph nodes also are removed during surgery to check for microscopic spread. Depending on the cancer's features, such as its depth, grade or closeness to other structures, chemotherapy or radiation may be recommended either before surgery or after surgery to reduce the risk of recurrence.
Stage 3 rectal cancer
In stage 3 rectal cancer, the tumor has spread to nearby lymph nodes but not to distant parts of the body. This is considered regional cancer, because it involves the local lymphatic system surrounding the rectum but not other organs.
- Stage 3A. The cancer has grown into the deeper layers of the rectum and has spread to 1 to 3 nearby lymph nodes. Or there are tumor deposits in tissues near the rectum without lymph node involvement but no distant metastasis.
- Stage 3B. The cancer has grown through the layer of muscle tissue in the rectal wall and may have reached perirectal tissues or even surrounding structures. It also has spread to 1 to 3 regional lymph nodes but not to distant sites.
- Stage 3C. The cancer has spread to 4 or more nearby lymph nodes, regardless of how far the tumor has grown within or beyond the rectum. Distant metastasis is still not present.
Stage 3 rectal cancer is typically treated with a combination of therapies. Most people receive chemotherapy and radiation before surgery to shrink the cancer, an approach called neoadjuvant therapy. This can be followed by surgical removal of the rectum and nearby lymph nodes. After surgery, chemotherapy may be recommended to reduce the risk of recurrence. In some people, rectal cancer may go away with chemotherapy and radiation alone, and surgery is not necessary.
Stage 4 rectal cancer
In stage 4 rectal cancer, the cancer has spread to distant parts of the body, such as the liver, lungs or the lining of the abdominal cavity, called the peritoneum. This is called metastatic or distant rectal cancer.
- Stage 4A. The cancer has spread to one distant organ, such as the liver or lungs, or to distant lymph nodes, but not to multiple locations.
- Stage 4B. The cancer has spread to more than one distant organ or distant set of lymph nodes.
- Stage 4C. The cancer has spread to distant parts of the peritoneum.
Treatment for stage 4 rectal cancer mainly relies on chemotherapy. Targeted therapy and immunotherapy may be recommended for people whose cancer cells have specific gene changes. Radiation can be used to relieve symptoms or temporarily shrink the cancer. Surgery can be considered in rare, specific situations.
Depending on your situation, you may be eligible to take part in a clinical trial. Ask your healthcare team if there are available options for your type of cancer.
How fast does rectal cancer spread?
Most rectal cancers begin as growths in the lining of the rectum, such as adenomas, which are a type of polyp. These polyps often grow slowly and may take many years to become cancerous. However, not all polyps turn into cancer.
Once rectal cancer develops, how quickly it grows or spreads depends on several factors. These include the type and grade of the cancer cells, whether the cancer has invaded deeper layers of the rectum, and your overall health and age. Some cancers stay localized for a while, while others may spread more quickly to nearby lymph nodes or distant organs such as the liver or lungs.
Looking ahead
Thanks to recent advancements in rectal cancer treatment, many people are living longer with better quality of life. Your experience with cancer is unique, and your care team is here to support you through each step. After treatment, regular follow-ups can help manage your health and monitor for any signs of recurrence.
Sept. 12, 2025