Know Your Breast Tumor Size

Compare These Objects With Your Breast Tumor Size

Tumor Scale
Tumor Scale. Credit: Photo © Pam Stephan

Finding out the exact size of your breast cancer tumor affects the staging of your cancer and your treatment decisions. Do you know what size your tumor is?  Here's a good way to visualize your tumor size, using common foods you are probably familiar with.

In this photo, several objects are used to offer a scale comparison in centimeters. The black peppercorn and the black-eyed pea would fit into the T-1 category. The cranberry and walnut would be in T-2, and the lime would appear in T-3 class.

Breast cancer is staged by the TNM System: Tumor size, node status, and metastasis. This is also called the AJCC staging system.

Tumor Size is divided into four classes:

  • T-1 is from 0 - 2 centimeters.This is less than an inch in diameter, up to four-fifths of an inch. The size of a peppercorn up to the size of a black-eyed pea.
  • T-2 is from 2 - 5 cm. This range is from about four-fifths of an inch to two inches in diameter. The size of a cranberry to the size of a walnut.
  • T-3 is greater than 5cm. This is larger than two inches in diameter. The size of a lime.
  • T-4 is a tumor of any size that has broken through (ulcerated) the skin, or is attached to the chest wall.

How Tumor Size is Measured

Tumor sizes are measured by the radiologist using the mammogram or ultrasound image taken of your breast. But not all tumors are simple, round shapes that are easy to measure. The tumor could be elongated like a baked potato and the image could be at an angle so the radiologist can't see all of the dimensions. Some tumors have irregular edges and so it is hard to estimate the total diameter of the tumor. 

How Tumor Size Relates to Staging in Breast Cancer

Tumor size, lymph node status, and metastasis, are combined to calculate the stage of your breast cancer with the TNM system. This important information is used to assess your options for surgery, as well as local and systemic therapies.

T = Tumor Size: T1 = 0-2 cm, T2 = 2-5cm, T3 = >5cm, T4 = ulcerated or attached

N = Node Status: N0 = clear, or negative nodes, N1 = cancerous, or positive nodes

M = Metastasis: M0 = no spread of tumor, M1 = tumor has spread

Stage 0Pre-cancerous

Stage 1  T-1,  N-0,  M-0

Stage 2: Can be any of these combinations:

  • T-1, N-1, M-0.  Notation: T1 N0 M0
  • T-2, N-0 or N1, M-0 Notation: T2 N0 M0 or T2 N1 M0
  • T-3, N-0, M-0 Notation: T3N0M0

Stage 3: Can be any of these combinations:

  • T-Any, N-1, M-0  Notations: T1 N1 M0, T2 N1 M0, T3 N1 M0, T4 N1 M0
  • T-3, N-0 or N-1, M-0 NotationS: T3 N0 M0, T3 N1 M0
  • T-4, N-0, M-0 Notations: T4 N0 M0

Stage 4 T-Any size, N-Any status, M-1.
Notations: T1 N0 M1, T1 N1 M1, T2 N0 M1,T2 N1 M1,T3 N0 M1,T3 N1 M1, T4 N0 M1,T4 N1 M1

Learning More About Your Breast Cancer Diagnosis


Cancer Staging, National Cancer Institute, Updated January 6, 2015.

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