A study involving more than 2,000 patients has dispelled the myth that cancer biopsies cause cancer to spread. Published in Gut (2015; doi:10.1136/gutjnl-2014-307475), the study showed patients who underwent a biopsy had a better outcome and longer survival than patients who did not.

Researchers at the Mayo Clinic campus in Jacksonville, Florida, studied pancreatic cancer, but the findings likely apply to other cancers. The diagnostic technique used in this study, fine needle aspiration, is commonly used across tumor types, said the study’s senior investigator and gastroenterologist Michael Wallace, MD, MPH, professor of medicine.

Fine needle aspiration is a minimally invasive technique that uses a thin and hollow needle to extract a few cells from a tumor mass. A long-held belief by a number of patients and even some clinicians has been that a biopsy can cause some cancer cells to spread.

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While there have been a few case reports that suggest this can happen, though very rarely, there is no need for patients to be concerned about biopsies, said Wallace.

“This study shows that physicians and patients should feel reassured that a biopsy is very safe,” he said. “We do millions of biopsies of cancer a year in the US, but one or two case studies have led to this common myth that biopsies spread cancer.”

Biopsies offer “very valuable information that allow us to tailor treatment. In some cases, we can offer chemotherapy and radiation before surgery for a better outcome, and in other cases, we can avoid surgery and other therapy altogether,” Wallace said.

Surgery for pancreatic cancer is a very big operation, and most people should want to confirm they have cancer before undergoing surgery. One study has shown that 9% of patients who underwent surgery because of suspected pancreatic cancer actually had benign disease.

In the current study, the researchers examined 11 years (1998-2009) of Medicare data on patients with nonmetastatic pancreatic cancer who underwent surgery. The researchers examined overall survival and pancreatic cancer-specific survival in 498 patients who underwent EUS-FNA and 1,536 patients who did not undergo a biopsy.

During a mean follow-up time of 21 months, 285 patients (57%) in the EUS-FNA group and 1,167 patients (76%) in the non-EUS-FNA group died. Pancreatic cancer was identified as the cause of death for 251 patients (50%) in the EUS-FNA group and 980 patients (64%) in the non-EUS-FNA group.

Median overall survival in the EUS-FNA group was 22 months compared to 15 months in the non-EUS-FNA group.

“Biopsies are incredibly valuable. They allow us to practice individualized medicine—treatment that is tailored for each person and designed to offer the best outcome possible,” Wallace said.