Small Intestine Cancer

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Early Detection, Diagnosis, and Staging TOPICS

How is small intestine adenocarcinoma staged?

Staging is a process that tells the doctor how widespread your cancer may be when you are first diagnosed. It will show if the cancer has spread and how far. The treatment and outlook for small intestine cancer depends, to a large extent, on its stage. For early stage cancer, surgery may be all that is needed. For more advanced cancer, other treatments, such as chemotherapy or radiation therapy, may be required. Please be sure to ask your doctor to explain the stage of your cancer so that you can make the best choice about your treatment.

The staging system used is that of the American Joint Committee on Cancer (AJCC). It is also called the TNM system. Stages are described using the number 0 (zero) and the Roman numerals I through IV.

This staging system describes the spread of the cancer in relation to the layers of the wall of the small intestine. Because for most patients, this stage is unknown until after surgery, most doctors wait till then to decide on the cancer's stage. The stages described below are called pathologic stages. The pathologic stage is determined by the findings of the pathologist from looking at the cancer and other actual tissue that has been removed.

The AJCC/TNM System describes the extent of the primary Tumor (T), the absence or presence of metastasis to nearby lymph Nodes (N), and the absence or presence of distant Metastasis (M).

T categories for small intestine adenocarcinoma

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

These layers, from the inner to the outer, include the lining (mucosa), the fibrous tissue beneath this muscle layer (submucosa), a thick layer of muscle that contracts to force the contents of the intestines along (muscularis propria), and the thin outermost layers of connective tissue (subserosa and serosa) that cover the small intestine. The serosa is also known as the visceral peritoneum.

Tx: No description of the tumor's spread is possible because of incomplete information.

Tis: The cancer is only in the epithelium (the top layer of cells of the mucosa) − it has not grown into the deeper tissue layers. This is the earliest stage and is also known as carcinoma in situ (CIS).

T1: split into 2 groups

  • T1a: The cancer has grown from the top layer of cells of the mucosa and into the layer of connective tissue below (the lamina propria).
  • T1b: The cancer has grown through the mucosa and into the submucosa

T2: The cancer has grown through the mucosa and submucosa into the muscularis propria.

T3: The cancer has grown through the inner layers of the intestine wall (mucosa, submucosa, and muscularis propria) into the subserosa. It has not started to grow into any nearby organs or tissues.

T4: The cancer has grown through the entire wall of the small intestine (including the serosa). It may be growing into nearby tissues or organs.

N categories for small intestine adenocarcinoma

N categories indicate whether or not the cancer has spread to nearby lymph nodes.

Nx: No information about lymph node involvement is available (often because no lymph nodes have been removed).

N0: Lymph nodes near the tumor were checked and do not contain cancer.

N1: Cancer cells found in 1 to 3 nearby lymph nodes.

N2: Cancer cells are found in 4 or more nearby lymph nodes

M categories for small intestine adenocarcinoma

M categories indicate whether or not the cancer has spread to distant organs, such as the liver, lungs, or distant lymph nodes.

M0: No cancer has been found in other organs or tissues.

M1: Cancer has been found in other organs or tissues.

Stage grouping

The T, N, and M categories are combined (in a process called stage grouping) to determine the stage. The stage is expressed in Roman numerals from stage I (the least advanced stage) to stage IV (the most advanced stage). The following guide illustrates how TNM categories are grouped together into stages:

Stage 0: Tis, N0, M0

The cancer is in the earliest stage. It has not grown beyond the top layer of cells of the mucosa of the small intestine. This stage is also known as carcinoma in situ.

Stage I: T1 or T2, N0, M0

The cancer has grown from the top layer of cells of the mucosa and into deeper layers such as the lamina propria (T1a), the submucosa (T1b), or the muscularis propria (T2). It has not spread into nearby lymph nodes (N0) or distant sites (M0).

Stage IIA: T3 or T4, N0, M0

The cancer has grown through most of the wall of the small intestine and into the subserosa (T3 or T4). It has not yet spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIB: T4, N0, M0

The cancer has grown through the wall of the intestine and into the serosa or into nearby tissues or organs (T4). It has not yet spread to nearby lymph nodes (N0) or to distant sites (M0).

Stage IIIA: Any T, N1, M0

The cancer has spread to 1 to 3 nearby lymph nodes (N1) but not to distant sites (M0).

Stage IIIB: Any T, N2, M0

The cancer has spread to 4 or more nearby lymph nodes (N2) but not to distant sites (M0).

Stage IV: Any T, Any N, M1

The cancer has spread to distant sites such as the liver, lung, peritoneum (the membrane lining the abdominal cavity), or ovary.


Last Medical Review: 02/04/2013
Last Revised: 02/14/2014