Pathology

Any time tissue is removed from your body—from a colon polyp to a piece of a
tumor—it is sent to a pathologist for careful review under a microscope.

Pathology

Any time tissue is removed from your body—from a colon polyp to a piece of a tumor—it is
sent to a pathologist for careful review under a microscope.

Pathology reports on colonoscopy specimens usually reveal the type of polyp and determine if it was precancerous or cancerous.

Pathology reports after surgery that are done to remove a cancer and a portion of the colon or rectum, or those done after tumor biopsies, may share more information about if a tumor is cancerous, the size of the tumor, the tumor grade, and if it has spread to other organs.

Pathology reports typically include:

  • Size of the specimen(s) and the location(s) removed from
  • Description of the specimen(s) evaluated
  • Diagnosis (also called histologic type)

Pathology reports on colonoscopy specimens usually reveal the type of polyp and determine if it was precancerous or cancerous.

Pathology reports after surgery that are done to remove a cancer and a portion of the colon or rectum, or those done after tumor biopsies, may share more information about if a tumor is cancerous, the size of the tumor, the tumor grade, and if it has spread to other organs.

Pathology reports typically include:

  • Size of the specimen(s) and the location(s) removed from
  • Description of the specimen(s) evaluated
  • Diagnosis (also called histologic type)

Cancer Grades

A pathology report may reveal a histologic grade if your biopsy is cancerous. This grade indicates how quickly the cancer is expected to grow and spread.

  • GX: Grade cannot be determined.
  • G1: Cancer cells look similar to healthy cells. (Called well differentiated or low grade.)
  • G2: Cancer cells are somewhat different from healthy cells. This is called moderately differentiated or intermediate grade.
  • G3: Cancer cells barely look like healthy cells. This is called poorly differentiated or high grade.
  • G4: Cancer cells are very abnormal looking. Highest grade and typically grow and spread faster than lower grade tumors. Also called undifferentiated or high grade.

Cancer Grades

A pathology report may reveal a histologic grade if your biopsy is cancerous. This grade indicates how quickly the cancer is expected to grow and spread.

  • GX: Grade cannot be determined.
  • G1: Cancer cells look similar to healthy cells. (Called well differentiated or low grade.)
  • G2: Cancer cells are somewhat different from healthy cells. This is called moderately differentiated or intermediate grade.
  • G3: Cancer cells barely look like healthy cells. This is called poorly differentiated or high grade.
  • G4: Cancer cells are very abnormal looking. Highest grade and typically grow and spread faster than lower grade tumors. Also called undifferentiated or high grade.

Stage Classification

Cancer grades are different from cancer stages, because grades are based on what the cells look like under a microscope and not where the cells have gone, which is how staging is determined. Before surgery, most staging is a clinical stage, determined by the colonoscopy, biopsy, labs, and imaging. After surgery, it’s a pathologic stage, determined by all the above plus the colorectal specimen including lymph node status and invasion into adjacent organs. This gives a clearer picture of the stage of the cancer.

Your pathology report may tell you the TNM classification of your biopsy. This is used to stage your cancer. Your tumor will be given a score in each of these areas, and the score will determine your stage of cancer:

  • T (tumor): How far the tumor has grown into or through the colon or rectum wall. (scored from 0–4)
  • N (node): Whether any lymph nodes near the original tumor have cancer in them (scored from 0–3)
  • M (metastasis): Whether cancer has spread to areas or organs outside the colon (scored from 0 to M1, M1a and M1b)

Based on your TNM score, you will receive a stage 0, stage I, stage II, stage III, or stage IV diagnosis. Sometimes a, b, and c are added to your cancer stage to further subclassify the stage of the tumor as well, which is also determined by the TNM score.

Stage Classification

Cancer grades are different from cancer stages, because grades are based on what the cells look like under a microscope and not where the cells have gone, which is how staging is determined. Before surgery, most staging is a clinical stage, determined by the colonoscopy, biopsy, labs, and imaging. After surgery, it’s a pathologic stage, determined by all the above plus the colorectal specimen including lymph node status and invasion into adjacent organs. This gives a clearer picture of the stage of the cancer.

Your pathology report may tell you the TNM classification of your biopsy. This is used to stage your cancer. Your tumor will be given a score in each of these areas, and the score will determine your stage of cancer:

  • T (tumor): How far the tumor has grown into or through the colon or rectum wall. (scored from 0–4)
  • N (node): Whether any lymph nodes near the original tumor have cancer in them (scored from 0–3)
  • M (metastasis): Whether cancer has spread to areas or organs outside the colon (scored from 0 to M1, M1a and M1b)

Based on your TNM score, you will receive a stage 0, stage I, stage II, stage III, or stage IV diagnosis. Sometimes a, b, and c are added to your cancer stage to further subclassify the stage of the tumor as well, which is also determined by the TNM score.

Immunohistochemistry

Most colorectal cancers form from glands in the inner wall of the colon or rectum that make mucus. These tumors are called adenocarcinomas.

Once an adenocarcinoma or any tumor is sent to pathology, immunohistochemistry (IHC) should be performed. This is a test that looks for the presence or absence of certain proteins in the tumor to determine if you could have a hereditary form of cancer.

The proteins the IHC looks for are considered mismatch repair proteins (MMR), and they
include: MLH1, PMS2, MSH2, and MSH6. Depending on if any of these proteins are present or absent in your pathology report, you may be referred to meet with a genetic counselor.

Immunohistochemistry

Most colorectal cancers form from glands in the inner wall of the colon or rectum that make mucus. These tumors are called adenocarcinomas.

Once an adenocarcinoma or any tumor is sent to pathology, immunohistochemistry (IHC) should be performed. This is a test that looks for the presence or absence of certain proteins in the tumor to determine if you could have a hereditary form of cancer.

The proteins the IHC looks for are considered mismatch repair proteins (MMR), and they
include: MLH1, PMS2, MSH2, and MSH6. Depending on if any of these proteins are present or absent in your pathology report, you may be referred to meet with a genetic counselor.

Who gets the pathology report?

The doctor who collected and sent the specimen, usually your GI specialist and/or surgeon. If your primary care doctor ordered the colonoscopy, they will also likely receive the report.

Timing

It can take 10–14 days for your pathology report to come in. Follow up with your doctor’s office if they haven’t contacted you about your results. Your report will dictate your next steps.

Each time you have polyps removed during a colonoscopy and/or each time you have surgery or a biopsy performed, you will receive a pathology report.

Who gets the pathology report?

The doctor who collected and sent the specimen, usually your GI specialist and/or surgeon. If your primary care doctor ordered the colonoscopy, they will also likely receive the report.

Timing

It can take 10–14 days for your pathology report to come in. Follow up with your doctor’s office if they haven’t contacted you about your results. Your report will dictate your next steps.

Each time you have polyps removed during a colonoscopy and/or each time you have surgery or a biopsy performed, you will receive a pathology report.