Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die and new cells take their place. Sometimes this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor.

Defining Tumors

A tumor is a clump of abnormal cells. Tumors can be either benign or malignant.

  • Benign tumors are not cancer. They can grow large, but they do not invade tissues or travel to other areas of the body.
  • Malignant tumors are cancer. When tumors spread elsewhere in the body, it is called metastasis. Cancer that is metastatic has spread away from the original (primary) site where it was found.

Tumor Staging

Your doctor will learn more about your cancer through staging. Staging is a system doctors use to describe a malignant tumor by its size and how far it has spread. Your doctor may order tests to stage the cancer. These tests show how large the tumor is and if it has spread to other parts of your body. Staging helps your doctor plan your treatment. It also helps your doctor plan treatment goals discussions. Cancer is often staged as soon as a tumor type has been confirmed.

Different types of cancers may be staged using different systems. If you have a solid tumor, your doctor may describe it using the TNM staging system.

The TNM system gives 3 key pieces of Information:

  • T refers to the size of the original or primary tumor.
  • N describes whether the cancer has spread to nearby lymph nodes.
  • M shows whether the cancer has spread (metastasized) to other organs of the body.

Numbers are often added to the letters to provide additional information about your tumor. In general, the lower the number, the smaller the tumor and the less the cancer has spread. A higher number can mean more advanced cancer. For instance, a tumor staged as T1 N1 M0 is a small tumor that has spread outside the original site to nearby lymph nodes. It has not spread to other parts of the body.

After numbers have been determined for T, M, and N, many cancers are said to be in 1 of 5 stages:

Numbered Stage Definition
Stage 0 Early cancer that is present only in the layer of cells where it began.
Can also be called carcinoma in situ.
Stage I, II, and III Higher stage numbers are for cancer with greater tumor size and/or spread of cancer.
Stage IV The cancer has spread to another organ(s).

For some types of cancers—such as breast cancer, Hodgkin's disease, and non-small-cell lung cancer—the letters A, B, or X may be added after the stage number. These letters indicate more information about the tumor.

Talk with your doctor to find out more about the stage of your tumor and what it means for your treatment.

A Closer Look: Yvonne*
Yvonne
Yvonne's doctor stages her breast tumor as T4 N2 M0. This means it is a large tumor that has spread outside the original site to nearby lymph nodes. But it has not spread to other parts of the body.
Her doctor tells her that the size of her tumor and how far it has spread means the cancer is in stage III. The tumor has also grown into the chest wall, so a "B" is added to the stage number (shown as stage IIIB).
Her doctor prescribes surgery followed by a chemotherapy (chemo) regimen.
Yvonne's doctor explains about chemo side effects that she may experience with this regimen, including fatigue, hair loss, and low blood cell counts.
Yvonne asks her doctor to help her prepare for these chemo side effects.
She takes notes during visits with members of her care team. She makes a list of things she can do to help manage chemo side effects.
She reviews her diet with a nutritionist who gives Yvonne tips on eating well during her course of treatment.

*This is a fictional case study based on chemo patient experiences. Your experience is unique. Your doctor and care team will create a plan that will best treat your type of cancer and manage your chemo side effects.

Tumor Grading

Your doctor can learn more about your cancer through grading. A doctor called a pathologist will look at cells from your tumor. This may include studying the cells under a microscope to determine the grade of the tumor. The less the cancer cells look like normal cells, the higher they are graded. Lower-graded cells tend to grow more slowly and look more like normal cells. Higher-graded cells tend to grow and spread quickly. The figure in the following case study is an example of grading in prostate cancer.

A Closer Look: Ricardo*
Ricardo
Ricardo is diagnosed with prostate cancer. The pathologist looks through a microscope at cells taken from the affected area.
Below is an example of what kind of cells might be seen. You will see that 1 = cells that look normal and 5 = extremely abnormal cells.
The pathologist grades Ricardo's cancer as 3A.
Grading of prostate cells under a Microscope
His doctor determines the course of treatment for Ricardo's stage and grade of cancer.
Ricardo has heard that side effects are common in chemotherapy. He asks his doctor how he can prepare for and manage chemo side effects.

*This is a fictional case study based on chemo patient experiences. Your experience is unique. Your doctor and care team will create a plan that will best treat your type of cancer and manage your chemo side effects.

  • The Chemotherapy and Infection Discussion Guide can help you understand your
    risk of infection

    Infection can be a serious side effect of strong chemo. Find out the factors that affect your risk of infection. Simply answer a few questions, and then print your results to share with your doctor.

    Use the Chemotherapy and Infection Discussion Guide to find out more.