Stage 3 Colon Cancer

Symptoms, Diagnosis, Treatment, and Prognosis

Table of Contents
View All
Table of Contents

Stage 3 colon cancer is the stage of the disease when the tumor has spread beyond the lining of the colon to nearby lymph nodes. Although the lymph nodes will contain cancer cells, the disease will not yet have spread to distant organs.

With treatment, many stage 3 colon cancers can be placed into remission, meaning that the signs and symptoms of cancer will have disappeared, in some cases forever. At other times, the remission may be partial and the treatment will be used to slow disease progression, improve a person's prognosis, and increase survival times.

With improved therapies and treatment protocols, people with stage 3 colon cancer are living longer than ever.


While people with stage 1 and stage 2 colon cancer will often have no signs of the disease, those with stage 3 are more likely to develop overt symptoms. This is not always the case and depends largely on the size and location of the tumor.

In some cases, a tumor can cause an intestinal passage to narrow as the surrounding tissues begin to contract (leading to strictures) and the tumor itself takes up more and more of the interior space (leading to an obstruction).

At the same time, the bleeding that can be mild with stage 1 and 2 disease can intensify as the tumor breaks through the confines of the colon and invades nearby tissues. In some cases, the bleeding will be visible and, in others, may only be confirmed with testing.


Symptoms common to stage 3 colon cancer include:

  • Abdominal pain or cramps
  • Bloating and gas
  • Rectal bleeding
  • Blood in stool
  • Fatigue: Due to the loss of blood and the onset of anemia
  • Constipation: Due to partial bowel obstruction
  • Diarrhea: Due to the buildup of fluids behind an obstruction
  • Narrow or ribbon-like stools: Caused by intestinal stricture
  • Nausea and vomiting: Caused when fluids, solids, and gases become trapped in the colon
  • Loss of appetite: Often due to persistent nausea, abdominal pain, or feeling of early fullness
  • Unintended weight loss

It is not uncommon for diarrhea and constipation to be interspersed, wherein the inability to have a bowel movement will suddenly give way to explosive, watery stools followed by another period of constipation.


There are different types of colon cancer, some of which are common (like adenocarcinoma) and others of which are rare. These less-common types can sometimes manifest with distinct symptoms. Among them:

  • Mucinous adenocarcinoma: A less-common form of adenocarcinoma affecting mucus-producing cells, it is characterized by abundant secretion of mucus, which will be visible on stools.
  • Gastrointestinal stromal tumors (GIST): This condition affects cells in the wall of the colon and can sometimes manifest with a hardened mass in the abdomen that can be felt.
  • Leiomyosarcoma: These affect the smooth muscles of the colon and are more likely to cause tenesmus (the feeling that you need to defecate even when the bowel is empty).

Other rare forms of colon cancer, like signet ring carcinoma and primary melanoma, are more aggressive and can rapidly progress from stage 3 to stage 4 if not detected early.

Colon Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman


If colon cancer is suspected, your doctor will perform a battery of tests, starting with a physical examination and medical history.

The findings of the physical exam are typically non-specific but may reveal abdominal tenderness, abdominal distention (either with hyperactive or absent bowel sounds), a palpable mass, fecal impaction, significant weight loss, and evidence of rectal bleeding.

In addition to evaluating symptoms, your doctor will ask about your family history of cancer, whether you have been diagnosed with inflammatory bowel disease (IBD), and if you have any other risk factors for colon cancer. Based on these initial findings, other tests may be ordered.

Lab Tests

There are no blood, urine, or body fluid tests able to diagnose colon cancer, but they can confirm characteristic features of the disease. Among them:

Liver function tests (LFTs) and renal function tests may also be used to determine whether cancer, if present, has spread to the liver or kidneys.

A newer blood-based test, called the CellMax liquid biopsy, is proving effective in detecting advanced adenomatous polyps (precancerous) and colorectal cancer with an accuracy reported by the company of 76% and 100% respectively. Though it has not yet been approved by the Food and Drug Administration (and thus is not commercially available), some predict that it may one day replace imaging scans in the diagnosis of certain cancers.

Imaging Studies

Before more invasive procedures are performed, your doctor may order imaging scans to visualize the gastrointestinal tract. This typically includes one of two common tests:


A more direct method of diagnosis is colonoscopy, an outpatient procedure in which a flexible scope with a lighted fiber-optic camera directly visualizes the interior of the colon on a video monitor.

Colonoscopy is relatively non-invasive and typically performed under monitored anesthesia. The scope, called a colonoscope, is not only able to navigate the intestinal passageway but can also take photos and obtain tissue samples for examination in the lab.

Most diagnostic colonoscopies can be performed within 30 to 60 minutes, not including preparation and anesthesia recovery time.


A biopsy is considered the gold standard for colon cancer diagnosis. The procedure, which extracts tissue samples for examination in the lab, is performed during a colonoscopy and is the only way to definitively diagnose the disease.

To obtain a sample, special instruments are fed through the tube of the colonoscope to pinch, cut, or electrically resect pieces of tissue. Once obtained, the sample is sent to a pathologist who specializes in the causes and effects of disease.

By viewing the sample under the microscope (referred to as histopathology), the pathologist can confirm whether cancer cells are present and begin the process by which the cancer is characterized, staged, and graded.

Staging and Grading

Staging and grading are processes by which the extent and severity of the cancer are determined. Together, the tests help direct the appropriate course of treatment and help predict the likely outcome (referred to as the prognosis).

Cancer Staging

The staging of most solid tumors, including colon cancer, utilizes a staging system called the TNM Classification of Malignant Tumors, established by the American Joint Committee on Cancer (AJCC). The TNM system classifies the stage (progression) of cancer based on an alphanumeric system:

  • T describes the depth of invasion of the primary (original) tumor.
  • N describes the number of regional (nearby) lymph nodes with cancer.
  • M describes whether the cancer has metastasized (spread) to distant organs or not.

Numbers are also attached to each letter—from 0 to as high as 5—to describe the degree of involvement.

To aid with the staging, additional tests—such as a CT scan with iodine-based contrast agents, MRI with gadolinium contrast, or positron emission tomography with a CT scan (PET/CT)—may be ordered.

With stage 3 colon cancer, there will be a positive finding of a primary tumor and regionally affected lymph nodes but no signs of metastasis. The stage is further broken down into three substages—stage 3A, 3B, and 3C—with each advancing letter representing a progression of the disease.

Stage TNM Stage Description
3A T1-2 N1 M0 Tumor cells in 1 to 3 regional lymph nodes with cancer in either the mucosal or underlying muscle layer
  T1 N2a M0 Tumor cells in 4 to 6 regional lymph nodes with cancer in the mucosal layer
3B T3-4a N1 M0 Tumor cells in 1 to 3 regional lymph nodes with cancer extending just beyond the confines of the colon or in the surrounding peritoneum (abdominal cavity)
  T2-3 N2a M0 Tumor cells in 4 to 6 regional lymph nodes with cancer either in with the muscle layer or extending just beyond the confines of the colon in adjacent tissues
  T1-2 N2b M0 Tumor cells in 7 or more regional lymph nodes with cancer in either the mucosal or underlying muscle layer
3C T4a N2a M0 Tumor cells in 4 to 6 regional lymph nodes with cancer in the peritoneum
  T3-4a N2b M0 Tumor cells in 7 or more regional lymph nodes with cancer extending just beyond the confines of the colon or in the peritoneum
  T4b N1-2 M0 Tumor cells in at least 1 regional lymph node with direct invasion of the tumor into adjacent organs

Tumor Grade

In addition to staging, the tumor will be graded by the pathologist. The grade predicts the likely behavior of a tumor based on its morphology (i.e., the structure of cells and cell groupings).

The grading will involve stains and other histologic techniques to establish how different the cancer cells look from normal cells (referred to as cell differentiation). These features can usually tell the pathologist how aggressive or indolent (slow-growing) the cancer will be.

The cancer grades range from G1 to G4, with lower values conferring to slower, low-grade tumors and higher numbers conferring to more aggressive, high-grade tumors.

Grade Classification Cell Differentiation
G1 Low-grade Well-differentiated
G2 Intermediate-grade Moderately-differentiated
G3 High-grade Poorly-differentiated
G4 High-grade Undifferentiated


Stage 3 colon cancer is typically treated with surgery, chemotherapy, and, in some cases, radiation therapy. The treatment plan will often require several medical specialists, including a gastroenterologist, surgical oncologist, medical oncologist, radiation oncologist, and your general physician.

Typically, the medical oncologist oversees and helps coordinate all facets of cancer treatment, while the general physician confers with the specialists to manage your overall health. All are essential to your long-term health and well-being.

Ultimately, the aim of treatment is to achieve remission, ideally complete remission where there is no evidence of disease. Even if partial remission is achieved, treatment can slow cancer progression and extend disease-free survival.


Stage 3 colon cancer is typically treated with surgical resection, in which a surgeon will remove the affected portion of the colon. The procedure, called a partial colectomy or subtotal colectomy, will be accompanied by a lymphadenectomy in which nearby lymph nodes are removed.

The colectomy may be performed laparoscopically (with tiny "keyhole" incision and specialized narrow equipment) or with traditional open surgery. The cut ends are then sutured or stapled together in an anastomosis (surgical attachment).

Generally speaking, a lymphadenectomy—also known as lymph node dissection—is considered adequate when at least 12 lymph nodes are removed. The number of lymph nodes removed is based on a number of factors, including the extent of the resection, the location and grade of the tumor, and the age of the patient.


Chemotherapy is typically used in adjuvant therapy, meaning that is delivered after surgery to clear any remaining cancer cells. There are several forms of combination chemotherapy used in people with stage 3 colon cancer:

  • FOLFOX: A combination of 5-FU (fluorouracil), leucovorin, and oxaliplatin delivered by intravenous infusion
  • FLOX: A combination of leucovorin and oxaliplatin delivered by intravenous infusion accompanied by an injection of 5-FU delivered all at once a single (bolus) dose
  • CAPOX: A combination of Xeloda (capecitabine) and oxaliplatin

For advanced stage 3 tumors that cannot be removed completely with surgery, a course of chemotherapy along with radiation may be prescribed before surgery. The treatment, referred to as neoadjuvant therapy, can help shrink the tumor so that it is easier to resect.

For people with good performance status, the standard course of chemotherapy for stage 3 colon cancer is six months, given over seven or eight cycles.

Radiation Therapy

Radiation may sometimes be used as neoadjuvant therapy, typically in tandem with chemotherapy (referred to as chemoradiation therapy).

At other times, radiation may be used as adjuvant therapy, particularly with stage 3C tumors that have attached to a nearby organ or have positive margins (tissues left behind after surgery that have cancer cells).

For people who are not fit for surgery or whose tumor is inoperable, radiation therapy and/or chemotherapy may be used to shrink and control the tumor. In cases like this, a form of radiation called stereotactic body radiotherapy (SBRT) can deliver precise beams of radiation to ensure greater tumor control.


The prognosis of stage 3 colon cancer has improved enormously in the past decades. From the 1970s to the early 1990s, the mortality rate for colon cancer essentially stagnated. By the early 2000s, with improved screening methods and the introduction of newer therapies, the rate dropped by more than 2% annually and is now nearly half of what it was in the 1990s.

Even with improved prognosis, colorectal cancer is the fourth most common cancer in the United States, accounting for nearly 150,000 new diagnoses each year and over 50,000 deaths.

The prognosis of stage 3 colon cancer is reflected by survival rates. These are typically measured in five-year intervals and described by the percentage of people who live for at least five years following the initial diagnosis compared with people in the general population.

The survival rate is divided into three stages. The stages are based on epidemiological data collected by the National Cancer Institute in its Surveillance, Epidemiology, and End Result (SEER) program and are defined as follows:

  • Localized: A tumor confined to the primary site
  • Regional: A tumor that has spread to regional lymph nodes
  • Distant: A tumor that has metastasized

By definition, stage 3 colon cancer is considered regional.

Relative 5-Year Survival Rates for Colorectal Cancer
Stage Percentage (%) of Cases Relative 5-Year Survival
Localized 37% 90.6%
Regional 36% 72.2%
Distant 22% 14.7%
Unknown 5% 39%

The above-listed five-year survival rates are not cast in stone but only provide a general overview of expectations. Many people live well in excess of these estimate, and some never have evidence of the disease.

In the end, survival rates are based solely on the extent of the disease, irrespective of a person's age, health, sex, cancer type, or general health. All of these factors can positively (or negatively) influence survival times.


While it can be distressing to be diagnosed with stage 3 colon cancer, it is important to remember that even if the disease is advanced, it is still highly treatable. To better cope with the challenges of treatment and recovery, there are several things you can do:

  • Educate yourself. Knowing what to expect not only helps reduce stress but allows you to participate fully in your treatment decisions. Do not hesitate to ask questions or express fears or concerns. The more that you know and understand, the better and more informed your choices will be.
  • Eat appropriately. Colon cancer and cancer treatment can affect your appetite and lead to malnutrition. Start early by working with a nutritionist to formulate a dietary strategy, including how to find nourishment if you are nauseous, have lost your appetite, or are unable to tolerate solid foods.
  • Keep active. While it is important to get plenty of rest, an appropriate amount of daily exercise can help you feel less tired and increase your ability to cope. Don't overdo it, but rather confer with your oncologist about the level and kinds of activity you can reasonably pursue, including walking, swimming, or gardening.
  • Manage stress. Rest and exercise can certainly help, but you can also engage in mind-body therapies like yoga, meditation, and progressive muscle relaxation (PMR) to better center yourself on a daily basis. If you feel severely anxious or depressed, do not hesitate to ask your doctor for a referral to a psychologist or psychiatrist for help.
  • Seek support. Start by building a support network of family and friends who can help you emotionally and functionally (with transport, childcare, chores, etc.) By educating loved ones about your disease and treatment, they will better able to understand what you need. Support groups are also invaluable and are commonly offered by cancer treatment centers.

A Word From Verywell

Stage 3 colon cancer is not the same disease it was 20 years ago, and the outcomes are almost certain to improve as newer targeted therapies and immunotherapies increase survival times and the quality of life even in those with advanced metastatic disease.

Even if complete remission is not achieved, do not give up hope. Every case of colon cancer is different, with some people responding to certain therapies better than others. In addition to approved therapies, there are numerous clinical trials to explore, offering a possible bridge to future treatments.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Cancer Society. Survival rates for colorectal cancer. Updated January 29, 2021.

  2. American Cancer Society. Do I have colorectal cancer? Signs, symptoms and work-up. Updated February 8, 2021.

  3. Luo C, Cen S, Ding G, Wu W. Mucinous colorectal adenocarcinoma: clinical pathology and treatment optionsCancer Communications. 2019;39(1):13. doi:10.1186/s40880-019-0361-0

  4. Crystal JS, Korderas K, Schwartzberg D, Tizio SC, Zheng M, Parker G. Primary leiomyosarcoma of the colon: A report of two cases, review of the literature, and association with immunosuppression for IBD and rheumatoid arthritisCase Rep Surg. 2018;2018:1-5. doi:10.1155/2018/6824643

  5. Theodorpoulos DG. Uncommon colorectal neoplasms. Clin Colon Rectal Surg. 2011 Sep;24(3):161-70. doi:10.1055/s-0031-1286000

  6. Georgios SK, Bampali AD. Colorectal cancer. In: Bustamante M, ed. Colonoscopy and Colorectal Cancer Screening - Future Directions. InTech; 2013. doi:10.5772/53524

  7. American Society of Clinical Oncology. ASCO answers colorectal cancer. 2018.

  8. Digestive Disease Week. A highly sensitive and quantitative multimodal blood test for the detection of colorectal adenomas and cancer. May 3, 2020.

  9. National Institute of Diabetes and Digestive and Kidney Diseases. Colonoscopy. Updated July 2017.

  10. National Cancer Institute. Colorectal cancer screening (PDQ). In: PDQ Cancer Information Summaries [Internet]. Updated March 17, 2020.

  11. Bruening W, Sullivan N, Paulson EC, et al. Colorectal cancer. In: Imaging Tests for the Staging of Colorectal Cancer. September 2014.

  12. National Cancer Institute. Table 4. Definitions of TNM stages IIIA, IIIB, and IIICa. In: PDQ Cancer Information Summaries [Internet]. Updated 2017.

  13. National Cancer Institute. Tumor grade. Updated May 3, 2013.

  14. Recio-Boiles A, Cagir B. Colon cancer. In: StatPearls. 2021.

  15. Batista VL, Iglesias ACRG, Madureira FAV, Bergmann A, Duarte RP, Fonseca BFS da. Adequate lymphadenectomy for colorectal cancer: A comparative analysis between open and laparoscopic surgeryABCD, arq bras cir dig. 2015;28(2):105-8. doi:10.1590/S0102-67202015000200005

  16. Sobrero A, Lonardi S, Rosati G, et al. FOLFOX or CAPOX in stage II to III colon cancer: Efficacy results of the Italian three or six colon adjuvant trialJCO. 2018;36(15):1478-85. doi:10.1200/JCO.2017.76.2187

  17. Grothey A, Sobrero AF, Shields AF, et al. Duration of adjuvant chemotherapy for stage III colon cancerN Engl J Med. 2018;378(13):1177-88. doi:10.1056/NEJMoa1713709

  18. Häfner MF, Debus J. Radiotherapy for colorectal cancer: Current standards and future perspectivesVisc Med. 2016;32(3):172-7. doi:10.1159/000446486

  19. American Cancer Society. Radiation therapy for colorectal cancer. Updated June 29, 2020.

  20. National Cancer Institute. Cancer stat facts: Colorectal cancer. Updated 2021.