Colorectal cancer

Location and appearance of two example colorectal tumors
Longitudinally opened freshly resected colon segment showing a cancer and four polyps. Plus a schematic diagram indicating a likely field defect (a region of tissue that precedes and predisposes to the development of cancer) in this colon segment. The diagram indicates sub-clones and sub-sub-clones that were precursors to the tumors.
Colon cancer with extensive metastases to the liver
Relative incidence of various histopathological types of colorectal cancer. The vast majority of colorectal cancers are adenocarcinomas.
Micrograph of colorectal adenocarcinoma, showing "dirty necrosis".
A diagram of a local resection of early stage colon cancer
A diagram of local surgery for rectal cancer
Colon and rectum cancer deaths per million persons in 2012

Development of cancer from the colon or rectum (parts of the large intestine).

- Colorectal cancer
Location and appearance of two example colorectal tumors

76 related topics

Alpha

Sigmoidoscopy

Minimally invasive medical examination of the large intestine from the rectum through the nearest part of the colon, the sigmoid colon.

Minimally invasive medical examination of the large intestine from the rectum through the nearest part of the colon, the sigmoid colon.

However, although in absolute terms only a relatively small section of the large intestine can be examined using sigmoidoscopy, the sites which can be observed represent areas which are most frequently affected by diseases such as colorectal cancer, for example the rectum.

Polyp of sigmoid colon as revealed by colonoscopy. Approximately 1 cm in diameter. The polyp was removed by snare cautery.

Colorectal polyp

Polyp occurring on the lining of the colon or rectum.

Polyp occurring on the lining of the colon or rectum.

Polyp of sigmoid colon as revealed by colonoscopy. Approximately 1 cm in diameter. The polyp was removed by snare cautery.
Incidences and malignancy risks of various types of colorectal polyps.
Microvesicular hyperplastic polyp. H&E stain.
Microvesicular hyperplastic polyp. H&E stain.
Traditional serrated adenoma. H&E stain.
Gross appearance of a colectomy specimen containing two colorectal polyps and one invasive colorectal carcinoma
Micrograph of a tubular adenoma, the most common type of dysplastic polyp in the colon.
Micrograph of a sessile serrated adenoma. H&E stain.
Micrograph of a Peutz–Jeghers colonic polyp – a type of hamartomatous polyp. H&E stain.
Micrograph of a tubular adenoma – dysplastic epithelium (dark purple) on left of image; normal epithelium (blue) on right. H&E stain.
Micrograph of a villous adenoma. These polyps are considered to have a high risk of malignant transformation. H&E stain.
Paris classification of colorectal neoplasms.<ref>{{cite book|title=Colonoscopy and Colorectal Cancer Screening: Future Directions|author=Luis Bujanda Fernández de Piérola, Joaquin Cubiella Fernández, Fernando Múgica Aguinaga, Lander Hijona Muruamendiaraz and Carol Julyssa Cobián Malaver|contribution=Malignant Colorectal Polyps: Diagnosis, Treatment and Prognosis|year=2013|doi=10.5772/52697|isbn=9789535109495}} Creative Commons Attribution 3.0 License</ref>

Untreated colorectal polyps can develop into colorectal cancer.

Modern CT scanner

CT scan

Medical imaging technique used in radiology (x-ray) to obtain detailed internal images of the body noninvasively for diagnostic purposes.

Medical imaging technique used in radiology (x-ray) to obtain detailed internal images of the body noninvasively for diagnostic purposes.

Modern CT scanner
Drawing of CT fan beam and patient in a CT imaging system
Computed tomography of human brain, from base of the skull to top. Taken with intravenous contrast medium.
120x120px
Bronchial wall thickness (T) and diameter of the bronchus (D)
Example of a CTPA, demonstrating a saddle embolus (dark horizontal line) occluding the pulmonary arteries (bright white triangle)
160x160px
Types of presentations of CT scans:
- Average intensity projection
- Maximum intensity projection
- Thin slice (median plane)
- Volume rendering by high and low threshold for radiodensity
Typical screen layout for diagnostic software, showing one volume rendering (VR) and multiplanar view of three thin slices in the axial (upper right), sagittal (lower left), and coronal planes (lower right)
148x148px
3D human skull from computed tomography data
Left image is a sinogram which is a graphic representation of the raw data obtained from a CT scan. At right is an image sample derived from the raw data.

It has more recently been used for preventive medicine or screening for disease, for example, CT colonography for people with a high risk of colon cancer, or full-motion heart scans for people with a high risk of heart disease.

The simplified structure of beta-catenin.

Catenin beta-1

Protein that in humans is encoded by the CTNNB1 gene.

Protein that in humans is encoded by the CTNNB1 gene.

The simplified structure of beta-catenin.
Partners competing for the main binding site on the ARM domain of beta-catenin. The auxiliary binding site is not shown.
Simplified structure of the beta-catenin destruction complex. Note the high proportion of intrinsically disordered segments in the axin and APC proteins.
The moonlighting of beta-catenin.
Beta-catenin level regulation and cancer.

Mutations and overexpression of β-catenin are associated with many cancers, including hepatocellular carcinoma, colorectal carcinoma, lung cancer, malignant breast tumors, ovarian and endometrial cancer.

Scheme of digestive tract, with rectum marked

Rectum

Final straight portion of the large intestine in humans and some other mammals, and the gut in others.

Final straight portion of the large intestine in humans and some other mammals, and the gut in others.

Scheme of digestive tract, with rectum marked
The inside of a normal human rectum in a 70-year-old, seen during colonoscopy
Retroflexed view of the human rectum seen at colonoscopy showing anal verge
A digital rectal exam is conducted to investigate or diagnose conditions including of the prostate.
Arteries of the pelvis
Blood vessels of the rectum and anus
Cross-section microscopic shot of the rectal wall
Dog rectum cross-section (40×)
Microscopic cross-section of the rectum of a dog (400×), showing a high concentration of goblet cells in amongst the column-shaped lining. Goblet cells can be seen as the circular cells with a clear inner material (cytoplasm).

Rectal cancer, a subgroup of colorectal cancer specific to the rectum.

Radiation therapy of the pelvis, using a Varian Clinac iX linear accelerator. Lasers and a mould under the legs are used to determine exact position.

Radiation therapy

Therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator.

Therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator.

Radiation therapy of the pelvis, using a Varian Clinac iX linear accelerator. Lasers and a mould under the legs are used to determine exact position.
Radiation therapy for a patient with a diffuse intrinsic pontine glioma, with radiation dose color-coded.
Histopathology of radiation cystitis, including atypical stromal cells (“radiation fibroblasts”).
The beam's eye view of the radiotherapy portal on the hand's surface with the lead shield cut-out placed in the machine's gantry
A teletherapy radiation capsule composed of the following:
Varian TrueBeam Linear Accelerator, used for delivering IMRT
A SAVI brachytherapy device
X-ray treatment of tuberculosis in 1910. Before the 1920s, the hazards of radiation were not understood, and it was used to treat a wide range of diseases.

Contact x-ray brachytherapy (also called "CXB", "electronic brachytherapy" or the "Papillon Technique") is a type of radiation therapy using kilovoltage X-rays applied close to the tumour to treat rectal cancer.

Blood smear showing iron-deficiency anemia, with small, pale red blood cells.

Anemia

Blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin.

Blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin.

Blood smear showing iron-deficiency anemia, with small, pale red blood cells.
Main symptoms that may appear in anemia
The hand of a person with severe anemia (on the left, with ring) compared to one without (on the right)
Figure shows normal red blood cells flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin.
Peripheral blood smear microscopy of a patient with iron-deficiency anemia
A Giemsa-stained blood film from a person with iron-deficiency anemia. This person also had hemoglobin Kenya.

In the United States, the most common cause of iron deficiency is bleeding or blood loss, usually from the gastrointestinal tract. Fecal occult blood testing, upper endoscopy and lower endoscopy should be performed to identify bleeding lesions. In older men and women, the chances are higher that bleeding from the gastrointestinal tract could be due to colon polyps or colorectal cancer.

Cetuximab

Cetuximab, sold under the brand name Erbitux, is an epidermal growth factor receptor (EGFR) inhibitor medication used for the treatment of metastatic colorectal cancer and head and neck cancer.

Cards and bottle used for the Hemoccult test, a type of stool guaiac test

Fecal occult blood

Not visibly apparent (unlike other types of blood in stool such as melena or hematochezia).

Not visibly apparent (unlike other types of blood in stool such as melena or hematochezia).

Cards and bottle used for the Hemoccult test, a type of stool guaiac test
A LabCorp fecal occult blood immunoassay testing kit.
A positive traditional guaiac fecal occult blood test

Positive tests ("positive stool") may result from either upper gastrointestinal bleeding or lower gastrointestinal bleeding and warrant further investigation for peptic ulcers or a malignancy (such as colorectal cancer or gastric cancer).

Micrograph of a lung primary small cell carcinoma, a type of carcinoma. The clustered cancerous cells consist primarily of nucleus (purple); they have only a scant rim of cytoplasm. The surrounding pale staining, discoid cells are red blood cells. Cytopathology specimen. Field stain.

Carcinoma

Sometimes a type of carcinoma but is more often benign.

Sometimes a type of carcinoma but is more often benign.

Micrograph of a lung primary small cell carcinoma, a type of carcinoma. The clustered cancerous cells consist primarily of nucleus (purple); they have only a scant rim of cytoplasm. The surrounding pale staining, discoid cells are red blood cells. Cytopathology specimen. Field stain.

For some common tumors, however, classical staging methods (such as the Dukes classification for colon cancer) are still used.