Gastrointestinal Carcinoid Tumors

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Early Detection, Diagnosis, and Staging TOPICS

How are gastrointestinal carcinoid tumors staged?

Staging — or determining the stage of disease — is the process of finding out if the tumor has spread, and if it has, how far. To help stage the tumor, doctors might use several types of imaging, endoscopy, or other tests described in the previous section, "How are gastrointestinal carcinoid tumors diagnosed?"

The stage of the tumor, along with the place it started, tells us about the prognosis (outlook) for someone with a gastrointestinal (GI) carcinoid tumor. These 2 factors also help the doctor decide what treatment to recommend.

Localized, regional, and distant stages

GI carcinoid tumors/cancers can start in several different locations, and until recently there had been no standard system for describing their spread. In the past, many doctors simply divided GI carcinoid tumors into 3 general stages: localized, regional spread, and distant spread. This approach was fairly easy to understand and could be useful when choosing among treatment options. It might not be possible to tell a benign tumor from a cancer when it is localized because the cells can look the same under the microscope. Any tumor that spreads, though, is a cancer (by definition).

Localized

The cancer has not spread beyond the wall of the organ it started in (for example, the stomach, intestine, or rectum).

Regional spread

The cancer has either spread to nearby lymph nodes or it has grown through the wall of the organ where it started to grow into nearby tissues such as fat, ligaments, and muscle (or both).

Distant spread

The cancer has spread to tissues or organs that are not near the organ where the cancer started (such as the liver, bones, or lungs).

The AJCC TNM system

Modern staging of GI carcinoid tumors/cancers uses a system created by the American Joint Committee on Cancer (AJCC) that is known as the TNM system. The TNM system for staging has 3 key pieces of information:

  • T describes the size of the primary tumor, measured in centimeters (cm), and whether the cancer has spread to organs next to the tumor.
  • N describes the extent of spread to nearby (regional) lymph nodes.
  • M indicates whether the cancer has metastasized (spread) to other organs of the body.

Numbers or letters appear after T, N, and M to provide more details about each of these factors:

  • The numbers 0 through 4 indicate increasing severity.
  • The letter X means "cannot be assessed" because the information is not available.
  • The letters "is" mean "carcinoma in situ," or the tumor is contained within the top layer of cells and has not yet reached deeper layers of tissue.

The T categories for GI carcinoid cancers differ depending on where the cancer starts, but the N and M categories are the same. Once the T, N, and M categories for a tumor are known, the information is combined to determine the overall stage. This process is known as stage grouping.

T categories for carcinoid tumors of the stomach

The T category describes how far down through the stomach layers the cancer has grown. The wall of the stomach is made of 5 layers. From innermost to outermost, they are:

  • Mucosa: This innermost layer is where stomach acid and digestive enzymes are made. The mucosa has 3 parts: epithelial cells which lie on top of a layer of connective tissue (the lamina propria), which is on top of a thin layer of muscle (the muscularis mucosa).
  • Submucosa: This is a supporting layer under the mucosa.
  • Muscularis: This is a layer of muscle that moves and mixes the stomach contents.
  • Subserosa and serosa: These are the two outermost layers. They act as wrapping layers for the stomach.

TX: Primary (main) tumor cannot be assessed due to incomplete information.

T0: The primary tumor cannot be found.

Tis: The tumor is less than 0.5 mm (about half the width of a grain of rice) and the cancer cells are found only in the top layer of cells of the stomach lining. This is also known as carcinoma in situ or severe dysplasia.

T1: The tumor has grown from the top layer of cells and into deeper layers, such as the lamina propria or the submucosa. The tumor is 1 cm (less than half of an inch) or less.

T2: Either:

  • The tumor has grown into the lamina propria or submucosa (or both) and is greater than 1 cm.
  • OR

  • The tumor has grown through the lamina propria and submucosa and into the main muscle layer of the stomach (called the muscularis propria).

T3: The tumor has grown through the muscularis propria and into the subserosa.

T4: The tumor has grown into the serosa (the outer layer of tissue covering the stomach, also called the visceral peritoneum) or into nearby organs or structures.

T categories for carcinoid tumors of the small intestine

T categories of small intestine cancer describe the extent of spread through the layers that form its wall.

The layers of the intestine (from innermost to outermost) are:

  • Mucosa: This is the innermost layer of the intestine. It has 3 parts: the top layer of cells (called the epithelium), a thin layer of connective tissue (called the lamina propria), and a thin layer of muscle.
  • Submucosa: This is the fibrous tissue that lies beneath the mucosa.
  • Thick muscle layers (muscularis propria): This layer of muscle contracts to force the contents of the intestines along the tract.
  • Subserosa and serosa: These are the thin outermost layers of connective tissue that cover the small intestine. The serosa is also known as the visceral peritoneum.

TX: Primary (main) tumor cannot be assessed.

T0: The primary tumor cannot be found.

T1: The tumor has grown from the top layer of cells and into deeper layers, such as the lamina propria or the submucosa. The tumor is 1 cm (less than half of an inch) or less.

T2: Either:

  • The tumor has grown into the lamina propria or submucosa (or both) and is greater than 1 cm.
  • OR

  • The tumor has grown through the lamina propria and submucosa and into the main muscle layer of the colon (called the muscularis propria).

T3: The tumor has grown through the muscularis propria and into the subserosa, the pancreas, and/or the retroperitoneum (the area in back of the abdomen).

T4: The tumor has grown into the serosa (the outer layer of tissue covering the intestine, also called the visceral peritoneum) or into nearby organs.

T categories for carcinoid tumors of the colon or rectum

T categories for carcinoid tumors of the colon and rectum cancer describe the extent of spread through the layers that form its wall. These layers are similar to those found in the wall of the small intestine (see above). From innermost to outermost, they are:

  • Mucosa: This is the innermost layer of the intestine. It has 3 parts: the top layer of cells (called the epithelium), a thin layer of connective tissue (called the lamina propria), and a thin layer of muscle.
  • Submucosa: This is the fibrous tissue beneath the mucosa.
  • Thick muscle layers (muscularis propria): This layer of muscle contracts to force the contents of the intestines along the tract.
  • Subserosa and serosa: These are the thin outermost layers of connective tissue that cover the large intestine. The serosa is also known as the visceral peritoneum.

TX: Primary (main) tumor cannot be assessed due to incomplete information.

T0: The primary tumor cannot be found.

T1: The tumor has grown from the top layer of cells and into deeper layers, such as the lamina propria or the submucosa. The tumor is 2cm (about 4/5 of an inch) or less.

    T1a: The tumor is less than 1 cm across (1 cm is less than half an inch).

    T1b: The tumor is 1 to 2 cm across.

T2: Either:

  • The tumor has grown into the lamina propria or submucosa (or both) and is greater than 2 cm.
  • OR

  • The tumor has grown through the lamina propria and submucosa and into the main muscle layer of the colon (called the muscularis propria).

T3: The tumor has grown through the muscularis propria and into the subserosa or other tissue around the colon or rectum.

T4: The tumor has grown through the wall of the colon (or rectum) and into the serosa (also called peritoneum) and/or into nearby organs.

T categories for carcinoid tumors of the appendix

TX: Primary (main) tumor cannot be assessed.

T0: No signs of a primary tumor.

T1: The tumor is no more than 2 cm (2 cm is about 4/5 of an inch) across.

  • T1a: The tumor is no more than 1 cm across (1 cm is a little less than half an inch).
  • T1b: The tumor is larger than 1 cm but not larger than 2 cm across.

T2: Either:

  • The tumor is larger than 2 cm but not larger than 4 cm.
  • OR

  • The tumor has grown into the cecum (the first part of the large intestine).

T3: Either:

  • The tumor is larger than 4 cm.
  • OR

  • The tumor has grown into the ileum (the last part of the small intestine).

T4: The tumor has grown into nearby organs or tissues (such as the abdominal wall).

N categories for GI carcinoid tumors/cancers

NX: The cancer has spread to nearby (regional) lymph nodes and cannot be assessed.

N0: The cancer has not spread to nearby lymph nodes.

N1: The cancer has spread to nearby lymph nodes.

M categories for GI carcinoid tumors/cancers

M0: The cancer has not spread (metastasized) to distant organs or structures.

M1: The cancer has spread (metastasized) to distant organs or structures (such as the liver, lungs, bones, etc).

Stage groupings for carcinoid of the stomach

Stage 0: Tis, N0, M0: Carcinoma in situ: the tumor is less than 0.5 mm (and the cancer cells are found only in the top layer of cells of the stomach lining (Tis). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage I: T1, N0, M0: The tumor is 1 cm or less in size and has grown from the top layer of cells and into deeper layers, such as the lamina propria or the submucosa (T1). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIA: T2, N0, M0: Either the tumor has grown into the lamina propria or submucosa (or both) and is greater than 1 cm in size; OR the tumor has grown into the main muscle layer of the stomach (called the muscularis propria) (T2). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIB: T3, N0, M0: The tumor has grown through the muscularis propria and into the subserosa (T3). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIIA: T4, N0, M0: The tumor has grown into the outer layer of tissue covering the stomach (the serosa or visceral peritoneum) or into nearby organs or structures. The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIIB: any T, N1, M0: The tumor can be any size and may or may not have grown into nearby structures (any T). It has spread to nearby lymph nodes (N1), but not to distant sites (M0).

Stage IV: any T, any N, M1: The tumor can be any size and may or may not have grown into nearby structures (any T). It may or may not have spread to nearby lymph nodes (any N). The cancer has spread to distant sites (most often the liver).

Stage groupings for carcinoid of the small intestine

Stage I: T1, N0, M0: The tumor is 1 cm or less and has grown from the top layer of cells and into deeper layers, such as the lamina propria or the submucosa (T1). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIA: T2, N0, M0: Either the tumor has grown into the lamina propria or submucosa (or both) and is greater than 1 cm; OR the tumor has grown into the main muscle layer of the intestine (called the muscularis propria) (T2). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIB: T3, N0, M0: The tumor has grown through the muscularis propria and into the subserosa (T3). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIIA: T4, N0, M0: The tumor has grown into the outer layer of tissue covering the intestine (the serosa or visceral peritoneum) or into nearby organs or structures. The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIIB: any T, N1, M0: The tumor can be any size and may or may not have grown into nearby structures (any T). It has spread to nearby lymph nodes (N1), but not to distant sites (M0).

Stage IV: any T, any N, M1: The tumor can be any size and may or may not have grown into nearby structures (any T). It may or may not have spread to nearby lymph nodes (any N). The cancer has spread to distant sites (most often the liver).

Stage groupings for carcinoid of the colon and rectum

Stage I: T1, N0, M0: The tumor is 2 cm (about 4/5 of an inch) or less and has grown into the lamina propria and may have grown into the submucosa. The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIA: T2, N0, M0: Either the tumor has grown into the lamina propria or submucosa (or both) and is greater than 2 cm; OR the tumor has grown into the main muscle layer of the colon (called the muscularis propria). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIB: T3, N0, M0: The tumor has grown through the muscularis propria and into the subserosa or other tissue around the colon or rectum. The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIIA: T4, N0, M0: The tumor has grown through the wall of the colon (or rectum) and into the serosa (also called peritoneum) and/or into nearby organs. The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIIB: any T, N1, M0: The tumor can be any size and may or may not have grown into nearby structures (any T). It has spread to nearby lymph nodes (N1), but not to distant sites (M0).

Stage IV: any T, any N, M1: The tumor can be any size and may or may not have grown into nearby structures (any T). It may or may not have spread to nearby lymph nodes (any N). The cancer has spread to distant sites (most often the liver).

Stage groupings for carcinoid tumors of the appendix

Stage I: T1, N0, M0: The tumor is no more than 2 cm. The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage II: T2 or T3, N0, M0: The tumor is either larger than 2 cm or it has grown into the cecum (T2) or ileum (T3). The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage III: Either:

T4, N0, M0: The tumor has grown into nearby organs or tissues. The cancer has not spread to nearby lymph nodes (N0) or to distant sites (M0).

OR

Any T, N1, M0: The tumor can be any size and may or may not have grown into nearby structures (any T). It has spread to nearby lymph nodes (N1), but not to distant sites (M0).

Stage IV: Any T, any N, M1: The tumor can be any size and may or may not have grown into nearby structures (any T). It may or may not have spread to nearby lymph nodes (any N). The cancer has spread to distant sites (most often the liver).


Last Medical Review: 12/31/2013
Last Revised: 12/31/2013