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Cancer Explained
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Biopsy: How Cancer Is Confirmed

A plain-language guide to biopsies — the procedures that remove a tissue sample so a pathologist can check for cancer — based on National Cancer Institute resources.

NCI source

Last reviewed: 2023-01-17

30-Second Summary

  • A biopsy removes a sample of tissue so a pathologist can look at the cells under a microscope.

  • In most cases, a biopsy is the only way to tell for sure whether you have cancer.

  • Samples can be taken with a needle, through an endoscope, or during surgery.

  • The findings are written in a pathology report, which contains details about the diagnosis and can guide treatment.

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The full explanation.

The simple version

In most cases, a biopsy is the only way to tell for sure whether you have cancer. During a biopsy, a doctor removes a small sample of abnormal tissue. A pathologist then looks at the tissue under a microscope and runs other tests on the cells.

Scans and lab tests can point toward cancer, but they usually can't confirm it. A biopsy lets a specialist look directly at the cells — which is why it is so often the deciding test.

How the sample is taken

The biopsy sample may be obtained in several ways:

  • With a needle. The doctor uses a needle to withdraw tissue or fluid. This method is used for bone marrow aspirations, spinal taps, and some breast, prostate, and liver biopsies.
  • With endoscopy. The doctor inserts a thin, lighted tube called an endoscope into a natural body opening, such as the mouth or anus, and can remove some or all of the abnormal tissue through it. A colonoscopy (colon and rectum) and a bronchoscopy (windpipe, airways, and lungs) are examples.
  • With surgery. A surgeon removes an area of abnormal cells during an operation. In an excisional biopsy, the surgeon removes the entire area of abnormal cells, often with a little normal tissue around it. In an incisional biopsy, the surgeon removes just part of the abnormal area.

Comfort during a biopsy

Depending on the type of biopsy, you may receive a sedative or anesthesia. A sedative helps you relax and stay very still or sleep. Anesthesia keeps you from feeling pain and comes in three forms:

  • local anesthesia — loss of feeling in one small area of the body
  • regional anesthesia — loss of feeling in a part of the body, such as an arm or leg
  • general anesthesia — loss of feeling and a complete loss of awareness that seems like a very deep sleep

What happens next

The pathologist describes the findings in a pathology report, which contains details about your diagnosis and can help show which treatment options might work for you. Sometimes the tissue is tested further for tumor markers or biomarkers. If the biopsy shows cancer, you may have more tests to find out the stage and to help your team plan treatment.

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Common questions

What is a biopsy?

A biopsy is a procedure in which the doctor removes a sample of abnormal tissue. A pathologist then looks at the tissue under a microscope and runs other tests on the cells. In most cases, doctors need to do a biopsy to be certain that you have cancer.

Why do I need a biopsy if I already had scans?

Imaging tests and lab tests can suggest that cancer may be present, but they usually cannot confirm it on their own. A biopsy lets a pathologist look directly at the cells, which is often the only way to tell for sure if you have cancer and what type it is.

How is a biopsy sample taken?

There are several ways. With a needle, the doctor withdraws tissue or fluid — used for bone marrow aspirations, spinal taps, and some breast, prostate, and liver biopsies. With endoscopy, a thin, lighted tube is inserted through a natural opening (as in a colonoscopy or bronchoscopy). With surgery, a surgeon removes the abnormal area, either entirely (excisional) or in part (incisional).

Will a biopsy hurt?

Some biopsies may require a sedative or anesthesia so you are comfortable. A sedative helps you relax and stay still or sleep. Anesthesia keeps you from feeling pain and can be local (one small area), regional (a part of the body such as an arm or leg), or general (loss of feeling and awareness, like a deep sleep).

What happens to the sample after a biopsy?

A pathologist examines the tissue and describes the findings in a pathology report, which contains details about your diagnosis. The information in the report can also help show which treatment options might work for you. Sometimes the tissue is tested further for tumor markers or biomarkers.

Questions for your care team

Consider bringing these to your next appointment.

What kind of biopsy will I have, and why is that method best for me?
Will I have a sedative or anesthesia, and how should I prepare?
What are the possible risks or side effects of this biopsy?
When will the pathology results be ready, and who will explain them?
Will the sample be tested for tumor markers or biomarkers?
Quick quiz

Test your knowledge

0 of 4 answered

  1. Q1.According to this article, why is a biopsy so often the deciding test for cancer?
  2. Q2.Which of the following is one way described for taking a biopsy sample?
  3. Q3.According to this article, what is the difference between an excisional and an incisional biopsy?
  4. Q4.What does this article say happens to the sample after a biopsy?

This quiz checks understanding of educational content only. It is not medical advice. Open this quiz on its own page.

Related learning map

How this explanation connects to 17 other things you can explore — related topics, terms, questions, practice, and its NCI source.

Biopsy: How Cancer Is Confirmed