How is breast cancer diagnosed?
Breast cancer diagnosis usually begins when a screening mammogram shows an
abnormal area or when a person notices a breast change such as a lump, nipple
change, discharge, swelling, or skin change. An abnormal result does not always
mean cancer, but it usually needs follow-up testing.
Common diagnostic tools include diagnostic mammogram, breast ultrasound,
breast MRI, and biopsy. A biopsy is the key test that removes tissue or fluid
so cells can be examined under a microscope.
Main tests used in breast cancer diagnosis
01
Diagnostic Mammogram
A more detailed X-ray of the breast used when a screening mammogram or
breast symptom needs closer evaluation.
02
Breast Ultrasound
Uses sound waves to create images and may help evaluate a lump, cyst,
dense breast tissue, or lymph nodes.
03
Breast MRI
Uses magnets and a computer to create detailed breast images and may be
used in selected diagnostic or staging situations.
04
Biopsy
Removes tissue or fluid for microscopic examination and additional testing.
Biopsy types can include fine-needle, core needle, or surgical biopsy.
What does a breast cancer pathology report show?
A pathology report describes what the biopsy or surgical tissue shows under
the microscope. It may include the cancer type, tumor grade, whether the cancer
is invasive or in situ, margin information after surgery, lymph node results,
and biomarker results.
Cancer type
For example, ductal carcinoma, lobular carcinoma, DCIS, or invasive cancer.
Tumor grade
Describes how abnormal cancer cells look and how quickly they may grow.
ER / PR status
Shows whether tumor cells have estrogen or progesterone receptors.
HER2 status
Shows whether tumor cells have high HER2 expression or amplification.
Ki-67
A marker sometimes used to describe how actively cells are dividing.
Lymph nodes
Shows whether cancer cells are found in nearby lymph nodes.
What is breast cancer staging?
Staging is the process of finding out how much cancer is in the body and where
it is located. It helps doctors describe how serious the cancer is, plan
treatment, and discuss prognosis.
Breast cancer staging considers whether cancer is only in the breast, has
reached nearby lymph nodes, or has spread to distant organs.
TNM staging: Tumor, Nodes, Metastasis
The TNM system is central to breast cancer staging. T describes the primary
tumor, N describes nearby lymph nodes, and M describes distant metastasis.
T — Tumor
How large is the breast tumor, and has it grown into nearby tissue?
N — Nodes
Has cancer spread to nearby lymph nodes, such as underarm lymph nodes?
M — Metastasis
Has cancer spread to distant organs such as bone, liver, lung, or brain?
Breast cancer stages explained
Stage 0
In situ disease
Abnormal cells are present but have not invaded nearby breast tissue.
Stage I
Early invasive cancer
Usually smaller cancer with limited or no lymph node involvement.
Stage II
Larger or limited regional spread
May involve a larger tumor or nearby lymph nodes.
Stage III
More extensive regional disease
May involve larger tumors, multiple lymph nodes, or nearby structures.
Stage IV
Metastatic breast cancer
Cancer has spread to distant parts of the body.
Clinical stage vs. pathologic stage
Clinical staging is usually based on physical exam, imaging tests, and biopsy
results before surgery. Pathologic staging is based on examination of tissue
removed during surgery, including breast tissue and lymph nodes when removed.
Both staging approaches help doctors understand the cancer, but pathologic
staging can provide more detailed information after surgery.
Research context
Diagnosis and staging research may involve pathology, tumor tissue sections,
biomarker testing, ER, PR, HER2, Ki-67, lymph node evaluation, tumor grade,
molecular subtype analysis, and metastatic behavior.
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