• Michael Misialek, MD

Pathologist Responds to Breast Biopsy Diagnosis Study

How do I know if my breast biopsy is accurate? Who is the pathologist that read my biopsy? These are just a few of the questions you might be asking yourself after having seen the recent Journal of the American Medical Association (JAMA) study. If you have ever had a biopsy, these questions probably never came up. Now with this study casting doubts on diagnostic accuracy, many people are understandably anxious. The JAMA article has received wide-spread media coverage.

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Let’s break the study down and ease some anxiety. Perhaps most importantly, this provides a great opportunity to learn about one of the lesser known medical specialties, pathology…my specialty.

The JAMA study “Diagnostic Concordance Among Pathologists Interpreting Breast Biopsy Specimens,” published on March 17, 2015, revealed the following key finding:

  • Overall agreement between individual pathologists’ interpretations and that of an expert consensus panel was 75%, with the highest concordance for invasive breast cancer and lower levels of concordance for ductal carcinoma in situ (DCIS) and atypical hyperplasia.

While the study’s findings may not be surprising to physicians who understand the challenges of diagnosing complex breast cases, news of the article could lead to unnecessarily heightened anxiety for patients and the public as breast cancer is a highly publicized and pervasive disease.

The study confirmed that the majority of breast pathology diagnoses, especially at either end of the spectrum (benign without atypia and invasive breast cancer) are readily and accurately made by practicing pathologists regardless of practice setting. The overall concordance rate for invasive breast cancer cases was 96%. Issues with diagnostic discordance mainly center on the borderline between atypical hyperplasia and DCIS.

Why does this matter? Overdiagnosis can lead to unnecessary surgery, treatment and anxiety. Underdiagnois can lead to a delay in treatment. The bottom line is that experience matters. Factors that contributed to greater discordance included: a low case volume, small practice size, nonacademic practice and high breast density.

The study has many weaknesses. Chief among them was that only a single slide per case was given to each pathologist. As a practicing pathologist, this never happens. I will review multiple slides, often ordering several additional deeper sections and ancillary special stains, studying each carefully. This practice was prohibited in the study. Additionally, the study cases were a mixture of core biopsy and excision specimens. Diagnostic criteria vary between a needle core and excision. Often times it is not necessary to render an exact diagnosis on the core biopsy, but rather recognize an abnormality and recommend an excision for which additional tissue will clarify the diagnosis.

Even the experts disagreed in the study (75% initial concordance then 90% after discussion). This illustrates the fact that pathology is both a science and art. Experts may stress slightly different criteria in their pathology training programs. The “eye of a pathologist” is a difficult measure to quantify and is dependent on multiple factors that best function in real time, not an artificial study.

Another weakness is that there is no evidence that the experts were more accurate in predicting outcomes than test subjects. Perhaps most importantly a second opinion was not allowed in the study, even when study participants indicated uncertainty. These are in fact the very cases that would most likely have been shown around, sent out for consult and further worked up.

It is not realistic to introduce such a large caseload of breast biopsies that are heavily weighted towards atypical hyperplasia and DCIS. Since these borderline cases represent only a small fraction of breast biopsies in actual practice, diagnostic concordance in routine practice is higher than that reported in this study. No clinical information other than patient’s age was given to the study pathologists, and no imaging findings were included. In actual practice, integration of the clinical setting and imaging findings is routinely used in making a diagnosis.

The findings are not unique to pathology. All of medicine has grey zones, where controversy often exists. The study does have an important message for pathologists. As noted in the accompanying editorial, it should serve as a “call to action”. A better, more reproducible definition of atypical hyperplasia is needed.

The article highlights the need for an active quality management program in surgical pathology that includes targeted review of difficult or high risk cases. The College of American Pathologists (CAP) and the Association of Directors of Anatomic and Surgical Pathology have been developing an evidence-based guideline expected to be released in May to provide recommendations to reduce interpretive diagnostic errors in anatomic pathology.

The CAP is proactively addressing educational opportunities through advanced breast pathology training programs designed to provide a route for pathologists to demonstrate their expertise regardless of the setting in which they practice.

Patients can take steps to help ensure their breast biopsy is read accurately:

  • Inquire about the pathology laboratory that will examine your tissue sample. Is the laboratory accredited? The CAP accredits more than 7,600 laboratories worldwide and provides an online directory for patients.

  • Make sure the pathologists who are examining your tissue samples are board-certified.

  • Find out if your hospital has a multidisciplinary breast conference. This is a team of physicians and other health care professionals that meets regularly to discuss diagnosis and management of patients with breast disease, guaranteeing more consultation about the best approach for your care.

  • If your hospital doesn’t have a multidisciplinary breast conference, consider getting a second opinion. Second opinions are always welcome. Have your doctor send the biopsy slides to another laboratory and request they be read by a pathologist who specializes in breast pathology.

  • Seek out accurate and credible resources to help you understand your pathology report and diagnosis, such as the CAP’s resource, “How to Read Your Pathology Report.”

  • Most accredited surgical pathology laboratories include second opinion slide review as part of their quality management program. Ask about this.

Take home messages

This is an opportunity to get to know your pathologist. Consider meeting your pathologist. You can review your slides with a pathologist.

  • It is important for patients and the public to know that the JAMA study, by design, is not an accurate reflection of what happens in the “real world” clinical practice of pathology.

  • It is common practice for pathologists to obtain second opinions in difficult cases such as DCIS and atypical hyperplasia to avoid both underinterpretation and overinterpretation.

  • Because DCIS and atypical hyperplasia do not represent invasive breast cancer, women have time to make informed decisions about their health, including time to obtain a second opinion.

  • If a woman (or man) receives a diagnosis of DCIS or atypia, they may consider seeking a second opinion.

Remember, all treatment begins with a diagnosis. Take control of your healthcare, ask questions, get answers and become engaged, it makes for better care.

A version of this story can be found on WBUR's CommonHealth.

#breastcancer #biopsy #DCIS #atypicalhyperplasia

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