Before reading any of the following, please read Stephen Jay Gould's The Median Isn't the Message, which helps put into perspective some things about statistics.

And remember - somebody has to be in that survival percentage! Why not you?!

More detailed information is available by following the "source" links for each entry.

>>> My list of colon cancer resources. <<<

[ incidence ] [ screening ] [ risk factors ] [ symptoms ] [ staging ] [ treatment ]

links/info last checked/updated 19 Jul 2015


Incidence of colorectal cancer [ top ]

Colorectal cancer (CRC) is the third most common malignant neoplasm worldwide, and the third leading cause of cancer deaths in the United States. It is estimated that there will be 147,950 new cases diagnosed in the United States in 2020 and 53,200 deaths due to this disease. From 2007 to 2016, CRC incidence declined by 3.6% per year among adults aged 55 years and older. However, from 2007 to 2016, in adults younger than 55 years, CRC incidence rates have been increasing by 2% per year. From 2008 to 2017, mortality from CRC declined by 2.6% per year among adults aged 55 years and older but increased by 1% per year among adults younger than 55 years. Incidence is higher in men than in women. The incidence rates range from 40.0 per 100,000 per year in Hispanic men to 52.4 per 100,000 per year in African American men. In women, the incidence rates range from 28.8 per 100,000 per year in Hispanics to 39.1 per 100,000 per year in African Americans. The age-adjusted mortality rates are 16.9 per 100,000 per year in men and 11.9 per 100,000 per year in women. About 4.4% of Americans are expected to develop the disease within their lifetime, and the lifetime risk of dying from CRC is 1.8%. Age-specific incidence and mortality rates show that most cases are diagnosed after age 54 years and 78.7% of cases occur in patients aged 55 years and older; about 15% of CRC cases occur in patients aged 45 to 54 years.

Genetic, experimental, and epidemiologic studies suggest that CRC results from complex interactions between inherited susceptibility and environmental or lifestyle factors. Efforts to identify causes led to the hypothesis that adenomatous polyps (adenomas) are precursors of most CRCs. In effect, measures that reduce the incidence and prevalence of adenomas may result in a subsequent decrease in the risk of CRCs; however, some CRC mortality may be caused by fast-growing lesions or lesions that do not pass through an adenomatous phase. Overall, details about the growth rates of adenomas and CRC are unknown; most likely, there is a broad spectrum of growth patterns, including formation and spontaneous regression of adenomas.

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Screening for colon cancer [ top ]

There are several tests to detect colorectal cancer. Some of these are still under investigation. [ more detailed information ] 

(source)

Factors associated with an increased risk of developing colorectal cancer [ top ]

For the great majority of people, the major factor that increases a person's risk for colorectal cancer (CRC) is increasing age. Risk increases dramatically after age 50 years; 90% of all CRCs are diagnosed after this age. Incidence and mortality rates are higher in African Americans compared with other races; however, a meta-analysis found no evidence that African Americans have higher rates of precancerous lesions. The history of CRC in a first-degree relative, especially if before the age of 55 years, roughly doubles the risk. A personal history of CRC, high-risk adenomas, or ovarian cancer also increases the risk. Other risk factors are weaker than age and family history. People with an inflammatory bowel disease, such as ulcerative colitis or Crohn disease, have a much higher risk of CRC starting about 8 years after disease onset and are recommended to have frequent colonoscopic surveillance. A small percentage (<5%) of CRCs occur in people with a genetic predisposition, including familial adenomatous polyposis and hereditary nonpolyposis coli.

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More facts and figures.


Factors with adequate evidence of increased risk of colorectal cancer:
     Excessive alcohol use
     Cigarette smoking
     Obesity
     Family/personal history of colorectal cancer and other hereditary conditions
Factors with adequate evidence for a decreased risk of colorectal cancer
     Physical activity
Interventions with adequate evidence for a decreased risk of colorectal cancer
     Nonsteroidal anti-inflammatory drugs
     Aspirin (benefits or harms)
     Hormone therapy (estrogen plus progestin)
     Estrogen-only therapy
     Polyp removal (benefits or harms)
Factors With Inadequate Evidence of an Association With Colorectal Cancer
     Nonsteroidal anti-inflammatory drugs (NSAIDs) (benefits or harms)
     Calcium supplementation
     Dietary factors
Factors and interventions with adequate evidence of no association with colorectal cancer
     Estrogen-only therapy
     Statins (benefits or harms)

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More information regarding prevention and risk factors can be found at this MSKCC link.


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Symptoms of colon cancer [ top ]

Colon cancer can be challenging to detect because you may feel only slight symptoms or even none at all. By the time you do feel symptoms, the cancer may be more advanced.

These are symptoms you should not ignore, because they may be signs of colon cancer:
rectal bleeding or blood in your stool
a change in your bowel habits, such as diarrhea, constipation, or narrow stool that lasts more than a few days
unexplained abdominal pain or cramping
a persistent urge to have a bowel movement that doesn't go away after you have one
unexplained weakness and fatigue
unintended weight loss
a diagnosis of anemia
women who have bloating that doesn't go away or happens with unexplained weight loss


Contact your doctor if any of these problems are severe or continue longer than you think they should. If you have any rectal bleeding or blood in the stool, tell your doctor as soon as possible.

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Some information on screening.


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Staging of colon cancer [ top ]

Detailed information on current methods of dealing with colorectal cancer can be found at this link to the health professionals' version, or at this link to the patients' version (which is written in less technical language).

The TNM classification system is the newer system of tumor classification, made by the American Joint Committee on Cancer (AJCC). Dukes' and Modified Astler-Coller (MAC) are older systems, but you will still run across references to them. Below are an explanation of the TNM classification system; the most recent AJCC staging; equivalencies of the current staging system and the older staging systems; and the Dukes'/MAC versions of the classification system.

TNM classification explanation [ top ]
[ staging ] [ TNM explanation ][ AJCC staging ] [ old/new equivalents ] [ Dukes'/MAC staging ]

The stages are in the next section.

T assesses the primary tumor

TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
Tis: Carcinoma in situ, intramucosal carcinoma (involvement of lamina propria with no extension through muscularis mucosae)
T1: Tumor invades the submucosa (through the muscularis mucosa but not into the muscularis propria)
T2: Tumor invades the muscularis propria
T3: Tumor invades through the muscularis propria into pericolorectal tissues
T4: Tumor invades the visceral peritoneum or invades or adheres to adjacent organ or structure
- T4a: Tumor invades through the visceral peritoneum (including gross perforation of the bowel through tumor and continuous invasion of tumor through areas of inflammation to the surface of the visceral peritoneum)
- T4b: Tumor directly invades or adheres to adjacent organs or structures

N assesses the regional lymph nodes

NX: Regional lymph nodes cannot be assessed
N0: No regional lymph node metastasis
N1: One to three regional lymph nodes are positive (tumor in lymph nodes measuring ≥0.2 mm), or any number of tumor deposits are present and all identifiable lymph nodes are negative
- N1a: One regional lymph node is positive
- N1b: Two or three regional lymph nodes are positive
- N1c: No regional lymph nodes are positive, but there are tumor deposits in the subserosa, mesentery, or nonperitonealized pericolic, or perirectal/mesorectal tissues
N2: Four or more regional nodes are positive
- N2a: Four to six regional lymph nodes are positive
- N2b: Seven or more regional lymph nodes are positive
 
M assesses distant metastasis

M0: No distant metastasis by imaging, etc.; no evidence of tumor in distant sites or organs. (This category is not assigned by pathologists.)
- M1a: Metastasis to one site or organ is identified without peritoneal metastasis
- M1b: Metastasis to two or more sites or organs is identified without peritoneal metastasis
- M1c: Metastasis to the peritoneal surface is identified alone or with other site or organ metastases

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AJCC staging [ top ]
[ staging ] [ TNM explanation ][ AJCC staging ] [ old/new equivalents ] [ Dukes'/MAC staging ]
Stage 0 Tis N0 M0
Stage I T1 N0 M0
T2 N0 M0
Stage IIA T3 N0 M0
Stage IIB T4a N0 M0
Stage IIC T4b N0 M0
Stage IIIA T1 N2a M0
T1-2 N1/N1c M0
Stage IIIB T1-2 N2b M0
T2-3 N2a M0
T3-4a N1/N1c M0
Stage IIIC T3-4a N2b M0
T4a N2a M0
T4b N1-2 M0
Stage IVA any T any N M1a
Stage IVB any T any N M1b
Stage IVC any T any N M1c

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AJCC/Dukes'/MAC equivalencies [ top ]
[ staging ] [ TNM explanation ] [ AJCC staging ] [ old/new equivalents ] [ Dukes'/MAC staging ]

Note: Dukes' and Astler-Coller (MAC) have been superseded for some time by AJCC; this table is not entirely accurate due to there now being more subdivisions in TNM, but it is being left here for historical reference.

current: AJCC
old: Dukes'
old: MAC
Stage 0 Tis N0 M0 n/a
 n/a
Stage I T1 N0 M0 A A
T2 N0 M01
Stage IIA T3 N0 M0 B
 B2
Stage IIB
 T4a N0 M0
Stage IIC
 T4b
 N0
 M0
 B3
Stage IIIA T1-T2
 N1 / N1c
 M0 C C1
T1
 N2a
 M0
Stage IIIB
 T3-T4a N1 / N1c M0C2
T2-T3
 N2a
 M0
 C1 / C2
T1-T2
 N2b
 M0
 C1
Stage IIIC
 T4a
 N2a
 M0
 C2
T3-T4a N2b M0
T4b N1-N2
 M0
 C3
Stage IVA
 any T any N M1a n/a n/a
Stage IVB
 any T
 any N
 M1b
 n/a
 n/a

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Histopathologic Grade
is also defined by the pathologist and is a measurement of how well differentiated - how well specialized - the cells in the tumor are. A normal cell is very well differentiated. Cancer cells are always less differentiated. The less differentiated they are, the faster they usually grow and the more prone they are to metastasize.

GX: Grade cannot be assessed
G1: Well differentiated
G2: Moderately well differentiated
G3: Poorly differentiated
G4: Undifferentiated

(source)


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Older tumor classification systems [ top ]
[ staging ] [ TNM explanation ] [ AJCC staging ] [ old/new equivalents ] [ Dukes'/MAC staging ]

Dukes'

A: invasion into but not through the bowel wall
B: invasion through the bowel wall but not involving lymph nodes
C: involvement of lymph nodes
D: widespread metastases

Astler-Coller (MAC)

A: limited to mucosa
B1: extending into muscularis propria but not penetrating through it; nodes not involved
B2: penetrating through muscularis propria; nodes not involved
C1: extending into muscularis propria but not penetrating through it; nodes involved
C2: penetrating through muscularis propria; nodes involved
D: distant metastatic spread

(source)


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Treatment of colon cancer [ top ]

Please note: the information in this section was available in 2013; the information on cancer.gov has changed and does not appear to be as detailed now - and treatment has likely advanced in the last couple of years. The information below is left for reference. The links have been changed to where the old links now forward.

Detailed information on current (October 2020) methods of dealing with colorectal cancer can be found at this link to the physicians' version or at this link to the patients' version (which is written in less technical language).


STAGE 0 COLON CANCER

Stage 0 colon cancer is the most superficial of all the lesions and is limited to the mucosa without invasion of the lamina propria. Because of its superficial nature, the surgical procedure may be limited.

Standard treatment options for stage 0 colon cancer include the following:
Local excision or simple polypectomy with clear margins.
Colon resection for larger lesions not amenable to local excision.

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STAGE I COLON CANCER

Because of its localized nature, stage I colon cancer has a high cure rate.

Standard treatment options for stage I colon cancer include the following:

Wide surgical resection and anastomosis.

The role of laparoscopic techniques in the treatment of colon cancer was examined in a multicenter, prospective, randomized trial (NCCTG-934653 [NCT00002575]), comparing laparoscopic-assisted colectomy (LAC) with open colectomy. Three-year recurrence rates and three-year overall survival rates were similar in the two groups. The quality-of-life component of this trial has been published, and minimal short-term quality-of-life benefits with LAC were reported.

(source)


STAGE II COLON CANCER

Standard treatment options for stage II colon cancer include the following:

Wide surgical resection and anastomosis.

The role of laparoscopic techniques in the treatment of colon cancer was examined in a multicenter, prospective, randomized trial (NCCTG-934653 [NCT00002575]), comparing laparoscopic-assisted colectomy (LAC) with open colectomy. Three-year recurrence rates and three-year overall survival rates were similar in the two groups. The quality-of-life component of this trial has been published, and minimal short-term quality-of-life benefits with LAC were reported.

The potential value of adjuvant chemotherapy for patients with stage II colon cancer remains controversial. Although subgroups of patients with stage II colon cancer may be at higher-than-average risk for recurrence (including those with anatomic features such as tumor adherence to adjacent structures, perforation, and complete obstruction), evidence is inconsistent that adjuvant fluorouracil (5-FU)-based chemotherapy is associated with an improved OS compared with surgery alone.

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STAGE III COLON CANCER

Standard treatment options for stage III colon cancer include the following:

Wide surgical resection and anastomosis.

The role of laparoscopic techniques in the treatment of colon cancer was examined in a multicenter, prospective, randomized trial (NCCTG-934653 [NCT00002575]), comparing laparoscopic-assisted colectomy (LAC) with open colectomy. Three-year recurrence rates and three-year overall survival rates were similar in the two groups. The quality-of-life component of this trial has been published, and minimal short-term quality-of-life benefits with LAC were reported.

Adjuvant chemotherapy (more detailed information is available at the "source" link below)

(source)


STAGE IV AND RECURRENT COLON CANCER

Treatment options for stage IV and recurrent colon cancer include the following:
Surgical resection of locally recurrent cancer.
Surgical resection and anastomosis or bypass of obstructing or bleeding primary lesions in selected metastatic cases.
Resection of liver metastases in selected metastatic patients (5-year cure rate for resection of solitary or combination metastases exceeds 20%), or ablation in selected patients.
Resection of isolated pulmonary or ovarian metastases in selected patients.
Palliative radiation therapy.
Palliative chemotherapy.
Targeted therapy.
Clinical trials evaluating new drugs and biological therapy.
Clinical trials comparing various chemotherapy regimens or biological therapy, alone or in combination.

More detailed information is available at the "source" link below.

(source)


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