Colorectal cancer stage III and what it means

Stage 0. The earliest stage also called cancer (or carcinoma) in situ. Cancer cells are found only on the innermost layer (the mucosa) of the colon or rectum wall.

Stage I. The cancer has grown beyond the mucosa and invaded the adjacent layers  (submucosa and maybe the muscle layer) but is contained within the colon or rectum wall.  Cancer has not spread to nearby lymph nodes (small organs that are part of the immune system)

Stage II cancer has spread through the colon or rectum wall but has not spread to the regional lymph nodes. Stage II could be further divided into three stages:

• Stage IIA cancer has spread through the outermost layer of the colon or rectum wall (serosa) but has not spread to other organs or the regional lymph nodes.

• Stage IIB cancer has spread through the colon or rectum wall to the tissue that is wrapped around the internal organs, the lining of the abdomen, also called visceral peritoneum. Cancer has not spread out to the nearby lymph nodes.

• Stage IIC cancer has spread through the colon or rectum wall to nearby abdominal organs. Cancer has not spread into nearby lymph nodes or other organs in the body.

Stage III Cancer has spread from the innermost layer, the mucosa, through the adjacent layers of the wall (submucosa and the muscle layer) and into nearby lymph nodes (small organs that are part of the immune system). Stage III colorectal cancer could be further divided into three stages:

• Stage IIIA cancer has spread from the mucosa, the innermost layer of the wall to the adjacent layers, the submucosa and maybe into the muscle layer and to 1-3 lymph nodes. Cancer has not spread to other organs.

• Stage IIIB cancer has grown and spread beyond the outermost layer of the colon or rectum wall (serosa).  Cancer has also spread into 1-3 lymph nodes, However, cancer has not spread to other nearby organs.

• Stage IIIC cancer can be of any size and remain within the wall or expand beyond the wall of the colon or rectum to the abdominal lining, the visceral peritoneum.  Cancer has also spread into 4 or more nearby lymph nodes. However, cancer has not spread to other nearby organs.

Stage IV Cancer has spread beyond the wall of the colon or rectum, into the nearby lymph nodes and into other, remote organs such as liver, lung, and peritoneum. Stage IV colorectal cancer can be divided into three stages:

• Stage IVA cancer has spread beyond the colon or rectum wall to one other remote organ such as liver or lungs, or ovary and also to the nearby lymph nodes.

• Stage IVB cancer has spread beyond the colon or rectum wall to more than one organ such as liver, lungs, and ovaries as well as to nearby and distant lymph nodes.

• Stage IVC cancer has spread beyond the colon or rectum wall to distant part of the abdominal lining (the visceral peritoneum) and may have spread to other distant organs and lymph nodes.

Surgery, is the most common treatment for early stages colorectal cancer and most useful when cancer is localized in the early stages of the disease.  Colectomy is a surgical procedure that consist of the removal of the tumor, the surrounding healthy tissue and the nearby lymph nodes. In some cases, surgery is also used in patients diagnosed with later stages of the disease. Once, the cancer is removed, the remaining healthy ends of the colon or rectum will be re-attached to each other. Normal bowel function is often restored in about a week.

Colectomy can be done by an open surgery for which, the surgeon will make a long, vertical cut of the belly to access the colon or rectum.  Colectomy can also be done by a laparoscopic surgery , a minimally invasive technique, in which the surgeon cut few small incisions of the belly and a video camera is inserted through one of the cuts to assist the surgeon perform the surgery with specific tools through the other incisions.  

In the case that the healthy ends of the colon or the rectom cannot be attached together (temporarily or permanently), then, one end will be directed out of the body through a stoma, an opening in the abdominal wall and skin.  A ring placed on the abdominal wall will hold the end of the colon or rectum in place. A member of your care team will instruct you on how to manage the stoma following your surgery.

Radiation therapy is also considered a local therapy. This therapy uses high energy x-rays to kill the cancer cells.  The x-rays are directed to the specific location of the tumor. Radiation therapy is a common treatment for rectal cancer and could be given before or after surgery. Radiation therapy is not frequently used for colon cancer, except when there is a concern that a tumor is growing back in its original location. Radiation therapy is usually given five days a week for several weeks.

Chemotherapy is the most commonly used systemic therapy. Chemotherapeutic drugs kill cancer cells by blocking their ability to grow and divide, they also affect some healthy cells which is the reason patients experience side effects. Over the years, multiple chemotherapeutic drugs were developed for treating colorectal cancer.  Chemotherapy is usually given multiple times (cycles) over a period of time. Your medical oncologist and the care team will decide whether you receive one drug or a combination of different drugs. In some cases, chemotherapy could be given before surgery to reduce the size of the tumor, or after surgery to kill any remaining cancer cells that were not removed.

Targeted therapy is a type of systemic therapy also given as pills or directly into the bloodstream. Targeted therapies are drugs (chemicals) that were developed to block the specific driving forces within the cancer cells that allow them to grow and divide.

Because these forces are mainly active in cancer cells and not in healthy cells, these treatments are less toxic to healthy tissues and organs. Not all colorectal cancer share the same targets.  Your medical oncologist will order a biomarker test that will characterize the specific driving forces of your tumor and help determine the most suitable targeted therapy for you. In most cases, targeted therapy is used in combination with other treatments such as chemotherapy, radiation therapy and/or surgery.