Do PET Scans and Biopsies Help Spread Cancer? Find Out What the Oncologists Have to Say About This!

When someone is told they might have cancer, it feels like the ground has shifted and when the doctor mentions a biopsy or a PET scan, the first reaction from many patients and families is hesitation. Some even refuse to move ahead with the diagnostic plan. They’ve heard things like: “A biopsy will make the cancer spread” and “PET scans can activate cancer cells.” More often than not, these come from a relative forwarding a WhatsApp video, or even an alternative medicine practitioner claiming these tests are dangerous. But misinformation can be more fatal than the disease itself. So let’s break this down clearly.

What Are Biopsies and PET Scans?

Biopsies and PET scans are commonly used to diagnose and stage cancer. A biopsy involves removing a small sample of tissue for testing. Whereas, a PET scan uses a safe, low-dose radioactive sugar to highlight active areas in the body, including tumors.

These are powerful tools that help doctors understand what they’re dealing with. Yet some believe they might do more harm than good. The idea that a test can “trigger” cancer to spread is a myth and a harmful one at that.

Can a Biopsy Make Cancer Spread?

Biopsies are a routine, safe part of cancer diagnosis. In fact, they are essential. Without them, doctors cannot confirm the type of cancer or decide on the best treatment.

Dr. Raman Narang, Senior Consultant Oncologist at HealthPil, explains:

“Biopsies don’t cause cancer, that’s a common myth. PET-CT scans and mammograms do use radiation, but the risk of developing cancer from them is close to zero. What’s far more dangerous is delaying these tests and missing an early diagnosis.”

There are rare exceptions. In a few cancers like testicular tumors or kidney cancers, doctors may opt for a slightly different approach or use a needle biopsy under special precautions. But in the vast majority of cases, biopsies do not cause any spread.

The truth is, they help catch cancer early, when treatment has the best chance of success.

What About PET Scans? Do They Activate Cancer?

Again, the answer is no. PET scans are imaging tools. They don’t interfere with cancer physically. They don’t poke it or touch it. They simply capture how the body uses energy and since cancer cells tend to consume more glucose, they show up more brightly.

This doesn’t mean the scan is making the cancer grow. It only means the scan is doing what it’s designed to do: detect.

Dr. Nilaxi Khataniar, Consultant Radiation Oncologist at HealthPil, puts it clearly:

“Glucose is used by all the cells of the body, and is in fact the primary source of energy for the brain. Cancer cells, like all the other cells, do use glucose for their energy, but consuming sugar in no way leads to cancer or makes existing cancer grow faster. Similarly, PET scans, which track glucose uptake, are safe diagnostic tools and do not cause or spread cancer.”

Why Do People Still Believe These Myths?

Sometimes, after a biopsy or scan, a patient’s condition gets worse. It’s easy to think the test caused it. But what really happened is this:

● The cancer was already at an advanced stage.

● The symptoms would have worsened anyway.

● The test only revealed what was already happening inside the body.

It’s human nature to connect the dots emotionally. But medically, those dots often don’t connect the way we think they do.

What’s the Real Risk?

If someone avoids a biopsy or scan out of fear, the cancer may quietly grow. By the time it’s caught, it may no longer be treatable. Early detection can mean the difference between needing chemotherapy or just surgery. It can be the difference between life and death.

Many cancers like breast, lung, lymphoma, or sarcoma respond very well to treatment if caught early. But for that, we need to stop letting fear guide our choices.