GI Needle Biopsies Do Not Spread Cancer, Study Suggests

Nick Mulcahy

January 15, 2015

Needle biopsies of the pancreas are not associated with an increased risk for death in patients with pancreatic cancer, according to a retrospective study published online January 9 in Gut.

The findings reinforce the safety of ultrasound-guided fine-needle aspiration (EUS-FNA), say the study investigators, who are all from the Mayo Clinic.

EUS-FNA is a well-established technique for the diagnosis of suspicious pancreatic lesions. It helps identify malignant lesions that require major surgery and spares patients with benign lesions unnecessary surgical resection.

However, there has been some concern about the safety of EUS-FNA because of the "rare but serious" adverse event of "tumor seeding," write senior investigator Michael Wallace, MD, MPH, from the division of gastroenterology and hepatology at the Mayo Clinic in Jacksonville, Florida, and colleagues.

The phenomenon can occur when the needle, with its extracted pancreatic tumor cells, punctures the peritoneal cavity, resulting in gastric wall implantation and dissemination of those tumor cells.

There are a handful of case studies in the literature in which tumor seeding has been reported "along the needle track" (i.e., the needle path from body entry to the destination of the pancreas) or in the peritoneum.

The investigators note that some physicians avoid using EUS-FNA in pancreatic lesion management because of this improbable event. Furthermore, a general fear exists among patients, said Dr Wallace.

"We do millions of biopsies of cancer a year in the United States, but one or two case studies have led to this common myth that biopsies spread cancer," he said in a press statement.

So the Mayo team came up with a study idea.

"We hypothesized that if tumor cell dissemination occurs with EUS-FNA, survival after complete resection [of the pancreas] would be impaired," they write.

They used the linked Surveillance, Epidemiology, and End Results (SEER)–Medicare datasets to identify 2034 patients with locoregional pancreatic cancer who underwent curative-intent surgery from 1998 to 2009.

In this cohort, 498 (24%) patients underwent EUS-FNA for the work-up of suspicious pancreatic lesions and 1536 (76%) did not.

During a mean follow-up of 21 months, 285 patients (57%) in the EUS-FNA group died, as did 1167 (76%) in the non-EUS-FNA group.

Pancreatic cancer was identified as the cause of death for 251 patients (50%) in the EUS-FNA group and 980 (64%) in the non-EUS-FNA group.

Median overall survival was better in the EUS-FNA group than in the non-EUS-FNA group (22 vs 15 months).

In a multivariate Cox regression model, EUS-FNA was associated with better overall survival (hazard ratio [HR], 0.84; 95% confidence interval [CI], 0.72 - 0.99) and did not affect cancer-specific survival (HR, 0.87; 95% CI, 0.74 - 1.03).

Among the variables significantly associated with decreased overall survival were older age at diagnosis, nonwhite race, higher disease stage, higher Charlson Comorbidity Score, adenocarcinoma-type cancer, higher tumor histologic grade, earlier year of diagnosis, and no receipt of chemotherapy or radiation therapy.

In summary, the study showed that EUS-FNA does not have a negative impact on outcomes in patients who receive it.

"These data suggest that EUS-FNA can be safely performed for the work-up of suspicious pancreatic lesions," conclude the investigators.

That is good news, especially because the overall use of EUS-FNA appears to be on the upswing.

The use of EUS-FNA increased from 10% (18 of 172 patients) in 2001 to 47.1% (96 of 204 patients) in 2009 (P < .001), Dr Wallace and collegues report.

This is the second study of this subject to come out of the Mayo Clinic. In this study, the investigators looked at survival; in a previous study, investigators examined disease recurrence in 256 pancreatic cancer patients treated at the Mayo Clinic in Jacksonville (Endoscopy. 2013;45:619-626).

That study found no difference in cancer recurrence between the 208 patients who underwent EUS-FNA and the 48 who did not.

Dr Wallace reports financial ties with industry, including Olympus, Boston Scientific, NinePoint, and US Endoscopy.

Gut. Published online January 9, 2015. Abstract

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