First step in cancer treatment: Should we be afraid of biopsy?

“If a knife touches it, cancer will spread.”

I first heard this sentence when I was a child, when a neighbor fell ill. The doctor suspected cancer and recommended a biopsy. I vaguely remember someone saying in the kitchen, “But touching the tumor isn’t good.” There was only one question in everyone’s mind: What if the biopsy spreads the tumor?

Years passed, and these questionable rumors spread further through word of mouth and, more recently, through social media, fueling fear.

When it comes to our loved ones or our own health, such concerns run deep. Let’s address this anxiety with scientific facts: Can a biopsy spread cancer?

Why is a biopsy performed? 

Biopsy, is a medical procedure in which a small sample is taken from a lump or suspicious area in the body to be examined in a laboratory.

Doctors need this sample to understand the nature of the tumor—whether it’s benign or malignant. In fact, according to Cancer Research UK, biopsy is the only definitive way to determine if a tumor is cancerous.

Depending on the location of the suspicious tissue or organ, different biopsy techniques may be used. Your doctor will decide which type of biopsy is safest and most appropriate for your situation.

No — biopsy does not spread cancer

From a technical standpoint, it is possible for cancer cells to be dislodged during a biopsy. This is called tumor seeding — or in medical terms, needle tract seeding. It refers to tumor cells breaking off during the passage of the biopsy needle and settling along the needle’s path.

But this possibility does not mean it’s likely or dangerous. In fact, it is extremely rare. Scientific research clearly shows this:

• 2008: A review reported tumor seeding in liver cancer biopsies at a rate of only 2.7%.
• 2015: Another analysis found the rate was below 1% across various cancer types.
• 2019: In a study of 42 bladder cancer patients followed for 28 months, none showed tumor spread after biopsy.
• 2024: A recent review found that needle biopsy in breast cancer does not affect recurrence, metastasis, or overall survival.
• 2015 (Mayo Clinic): Research showed that biopsy actually leads to better treatment outcomes and longer survival, because it enables accurate diagnosis and treatment planning.

Lead researcher Dr. Michael Wallace emphasized:

“This study shows both doctors and patients should be reassured that biopsy is extremely safe. We perform millions of cancer biopsies each year in the U.S., yet one or two cases have led to a widespread myth that biopsies spread cancer.”

Real risks of biopsy: bleeding, infection, pain

The most common risks of biopsy are:

• Bleeding
• Infection
• Pain

Spreading cancer cells is not considered a realistic risk, as there is no evidence that it affects disease progression.

On the contrary, by enabling accurate diagnosis, biopsy allows for a personalized treatment plan—making it essentially the first step in cancer treatment.

Misinformation can delay correct treatment

False claims on social media can delay necessary treatments and lead to dangerous consequences. These claims are often based on personal anecdotes or incomplete information.

Such misinformation can discourage people from seeking medical help. If a critical step like biopsy is postponed, diagnosis is delayed, which poses serious health risks and can cause psychological and financial strain.

When it comes to our health or that of our loved ones, it’s normal to have doubts. But such claims exploit our fears. The healthiest step we can take is to approach content without scientific evidence with caution.

We are here to address all your questions about cancer-related claims.