Core needle biopsy alternative to more invasive proc - Academy News at the 2007 AAOS Annual Meeting

Core needle biopsy good alternative to more invasive procedures

By Peter Pollack

In recent decades, the focus of musculoskeletal tumor treatment has shifted toward limb-salvage surgery—an approach that can benefit from less invasive diagnostic procedures. According to the authors of scientific paper 265, in certain cases, core needle biopsy may serve as a less invasive alternative to traditional biopsies, which have high complication rates and often lead to unnecessary treatment alterations.

“The core needle biopsy is excellent for diagnosis and treatment planning when it is diagnostic for a specific pathologic process (both benign and malignant),” said the authors.

On the other hand, core needle biopsies are “highly unreliable for diagnostic and treatment purposes” if the sampling is found to have inflammatory, normal or tissue “suggestive” of a pathologic process. In these cases, said the authors, further tissue evaluation is necessary, “most reliably in the form of a subsequent, appropriately performed open biopsy.”

Safe and effective

According to the authors, previous studies have found core needle biopsy to be a safe and effective technique, with diagnostic accuracy ranging from 69 percent to 99 percent and complication rates between 0 percent and 6 percent. Their retrospective review of cases in a primary musculoskeletal tumor referral center found 100 percent accuracy (43 of 43) in diagnosing malignancy in soft-tissue lesions and a 93 percent accuracy (40 of 43) in defining specific histological tumor type.

Of the 119 biopsies studied, 105 were performed by a single ortho-paedic oncologist, and 14 were performed with computed tomography (CT) guidance by one of two musculoskeletal radiologists. Based on the initial pathology report, biopsy material was classified as diagnostic, inflammatory/normal or non-diagnostic. The researchers determined accuracy by adding the number of true positive and true negative biopsies, dividing by the total of all biopsies, and multiplying by 100.

Bone lesion biopsies had an accuracy of 82.5 percent in diagnosing malignancy and 77.5 percent in defining tumor type. Overall accuracy was 91.5 percent in determining malignancy and 85.5 percent in determining histological tumor type.

“The utility of core needle biopsy in diagnosis and preparation for definitive treatment of a musculoskeletal lesion relies heavily on the pathologist’s interpretation of the sampled tissue,” noted the authors. “Their evaluation of the tissue in terms of its adequacy for diagnosis, instead of the actual diagnosis, appears to be an additional important factor in ensuring the accuracy of individual biopsies.”

Important caveats

The researchers noted that in more than half (57 percent) of the cases in which the core biopsy was determined to be nondiagnostic by the pathologist, a second core biopsy or a follow-up open biopsy revealed a undiagnosed malignancy. “Even more importantly,” they said, “core biopsies that were reported as simply inflammatory tissue were found to have a 40 percent incidence of malignancy on subsequent open biopsy.”

The researchers noted that in more than half (57 percent) of the cases in which the core biopsy was determined to be nondiagnostic by the pathologist, a second core biopsy or a follow-up open biopsy revealed a undiagnosed malignancy. “Even more importantly,” they said, “core biopsies that were reported as simply inflammatory tissue were found to have a 40 percent incidence of malignancy on subsequent open biopsy.”

Additionally, the authors list several factors that may contribute to difficulties in musculoskeletal tumor diagnosis. Among these are sampling errors, tumor size, anatomic location and needle gauge. They note that as tumors enlarge, they can outgrow their blood supply, leading to necrotic areas in the central tumor mass. Although the best biopsy samples are typically found at the margins of the tumor, “targeting this area may lead to retrieval of normal or inflammatory tissue...from the reactive zone...instead of from the tumor itself.”

While concluding that core needle biopsy is a good choice for diagnosis and treatment planning when used for a specific pathologic process, the authors suggest a subsequent open biopsy for those that are found to have inflammatory, normal or tissue suggestive of a pathologic process.

“We believe this makes our observations even more important to institutions that perform low numbers of core needle biopsies,” they wrote. “Understanding the inherent difficulties with core needle biopsy and the need to confirm normal, inflammatory or nondiagnostic biopsy results may decrease the number of complications and adverse clinical outcomes based solely on diagnostic errors.

“The inherent limitations of this technique make it less reliable for definitely ruling out the presence of aggressive disease and highlight the need for further invasive tissue evaluation when normal, inflammatory or nondiagnostic tissue specimens are obtained.”

The authors include Matthew E. Oetgen, MD; Qusai Hammouri, MD; Gary E. Friedlander, MD, and Dieter M. Lindskog, MD—all of New Haven, Conn.; and Dawn M. Grosser, MD, of Corpus Christi, Texas. Dr. Friedlander serves as a consultant to Stryker Biotech and Biomimetic.


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