When a scan shows a suspicious lump or abnormality, many patients ask an important question: “If doctors can already see the tumour on CT, MRI or PET scan, why is a biopsy still needed?”
The reason is that imaging can show where an abnormality is located and how it behaves, but tissue examination is often required to determine exactly what the abnormal cells are.
What Is a Biopsy?
A biopsy is a medical procedure in which a sample of cells or tissue is removed from the body and examined by a pathologist.
The tissue may be studied under a microscope and may undergo additional laboratory tests to identify the exact disease.
Why Is a Biopsy Important in Cancer?
A biopsy can help answer important questions such as:
- Is the abnormality actually cancer?
- What type of cancer is present?
- What is the tumour subtype?
- How abnormal or aggressive do the cells appear?
- Are particular biomarkers present?
- Which treatments may be appropriate?
Why Is Imaging Alone Sometimes Not Enough?
CT, MRI, ultrasound and PET scans can identify suspicious areas, but some infections, inflammatory conditions and benign growths can resemble cancer on imaging.
Pathology provides direct information about the cells or tissues involved.
What Are the Different Types of Cancer Biopsy?
Fine Needle Aspiration
Fine Needle Aspiration, or FNA, uses a thin needle to collect cells or fluid from a suspicious area.
Core Needle Biopsy
A core needle biopsy removes small cylinders of tissue. It often provides more information about tissue architecture than fine needle aspiration.
Endoscopic Biopsy
A biopsy may be obtained during an endoscopy, such as:
- Gastroscopy
- Colonoscopy
- Bronchoscopy
Incisional Biopsy
During an incisional biopsy, only part of a suspicious mass is removed for testing.
Excisional Biopsy
An excisional biopsy removes the entire suspicious abnormality in selected situations.
Bone Marrow Biopsy
Bone marrow biopsy may be performed when doctors are investigating blood cancers or disorders involving the bone marrow.
What Happens to the Biopsy Sample?
After collection, the tissue is sent to a pathology laboratory.
A pathologist examines the sample and may perform additional tests such as:
- Special stains
- Immunohistochemistry
- Hormone receptor testing
- HER2 testing
- Molecular testing
- Genetic or biomarker testing
What Information Can a Cancer Pathology Report Contain?
Depending on the cancer, the report may include:
- Exact diagnosis
- Histological type
- Tumour grade
- Margins after surgery
- Lymph-node findings
- Immunohistochemistry results
- Hormone receptors
- HER2 status
- PD-L1 status
- Mismatch-repair proteins
- Other molecular biomarkers
Not every patient requires every test.
Can a Biopsy Cause Cancer to Spread?
This is one of the most common concerns patients have before undergoing biopsy.
For the vast majority of cancers, appropriately performed needle or surgical biopsy is an established diagnostic procedure and does not generally cause cancer to spread throughout the body.
There are certain specific tumours where the route and method of biopsy must be carefully planned. This is why biopsy should be performed according to specialist advice rather than through an inappropriate or unplanned procedure.
Can a Biopsy Result Be Inconclusive?
Yes. Occasionally, the sample may not provide enough information to establish a diagnosis.
Reasons may include:
- Insufficient tissue
- The needle missing the most representative part of the lesion
- Sampling mainly dead or damaged tissue
- The lesion being difficult to access
- Additional specialised tests being required
A repeat biopsy may then be advised.
What Is a Liquid Biopsy?
A liquid biopsy usually involves analysing blood for tumour cells, tumour DNA or other cancer-related material.
In selected cancers, liquid biopsy can provide useful information for molecular testing or treatment planning.
However, it does not universally replace a traditional tissue biopsy.
What Should You Ask Before Having a Biopsy?
Useful questions include:
- What type of biopsy is recommended?
- Why has this particular method been chosen?
- Do I need to stop any blood-thinning medicines?
- Will local anaesthesia or sedation be used?
- How long will the procedure take?
- When should the pathology result be available?
- Will enough tissue be collected for biomarker testing?
- What symptoms should I watch for after the biopsy?
Is Biopsy Always Required Before Cancer Treatment?
In many cancers, obtaining tissue confirmation before starting treatment is extremely important.
However, there are specific clinical circumstances where doctors may make decisions differently. The requirement for biopsy therefore depends on the cancer type, location, imaging findings and overall clinical situation.
Conclusion
A biopsy does much more than answer whether cancer is present.
Modern pathology can reveal the exact cancer type and important biological characteristics that may influence surgery, chemotherapy, targeted therapy, hormone therapy, immunotherapy and other treatment decisions.
A properly planned biopsy is therefore one of the most important steps in developing an individualised cancer treatment strategy.
This article is intended for educational purposes and does not replace personalised medical advice.
