May 19, 2023

The science behind a cancer diagnosis

Residents Drs. Margarita Consing-Gangelhoff and Claire Castaneda and pathologist Dr. Kristina Matkowskyj in a lab
From left to right, UW Department of Pathology and Laboratory Medicine residents Drs. Margarita Consing-Gangelhoff and Claire Castaneda and pathologist Dr. Kristina Matkowskyj

An important part of a patient’s oncology team involves highly-trained physicians the patient likely will never meet.

When a physician orders a biopsy of a concerning lump or lesion, that tissue sample is sent to pathologists to determine first whether the tissue is cancerous, and if so what type of cancer it is for treatment purposes. UW Health’s pathologists subspecialize in different organ systems of the body to best direct how samples are classified and tested to ensure an accurate, detailed diagnosis.

“It’s like being a detective,” said Dr. Kristina A. Matkowskyj, a pathologist who specializes in the gastrointestinal system.

One of the initial steps of tumor identification is to stain the sample and look for patterns that can give a clue about where the cancer is originating. Pathologists use what they know about the patient’s biology and medical history to help guide their investigation.

If the tumor cells have an uncommon growth pattern, or if pathologists are considering more than one tumor type, they can use immunohistochemistry to dig deeper. This is a staining technique that involves the use of multiple types of antibodies to see which markers are present in the tissue.

Matkowskyj said members of the pathology team frequently collaborate across subspecialties to evaluate unusual samples and discuss where the tumor may have started. This ensures the most efficient use of time and resources and, most importantly, optimizes the use of a limited amount of patient tissue.

“If I have an unusual looking tumor and I’ve already considered or excluded lesions within the gastrointestinal tract, I’ll bring it to my subspecialty pathology colleagues and ask, ‘What entities are you thinking about when looking at this tumor? Are there any I may not have considered?’ because we want to be strategic in how we select our stains/tests to determine tumor origin,” she said.

Immunohistochemistry is also useful for biomarker testing in specific subtypes of cancer, which give oncologists key information to decide which treatments would be most likely to benefit the patient. This information also is relevant for matching patients to appropriate clinical trials.

UW Health | Carbone Cancer Center's pathologists typically spend two to four days completing their analysis of biopsied tissue. Their detailed results include the grade of cancer and whether it is metastatic. Identifying specific biomarkers in tumor cells also helps the patient’s oncology care team determine which treatments are most likely to benefit the patient.

“Working closely with our medical and surgical oncology colleagues, we have identified workflows for a wide array of cancer types. This enables pathologists to order and report tumor biomarkers at the time of diagnosis, so patients are not waiting on additional testing,” she said. “Testing up front ensures their care is personalized to them and the type of tumor they have and there are no delays in delivering treatment.”