Tumor Grades and Understanding Your Pathology Report

At the 2015 American Urological Associations Annual Scientific Meeting, findings were presented with regards to tumor size predicting more aggressive cancers. A study from the Washington University School of Medicine in St. Louis, MO., identified 975 patients with a T1a N0M0 RCC tumor treated through a robotic partial nephrectomy. 

Researchers determined that a larger tumor size is associated with high grade pathology in patients with a pT1a renal cell carcinoma (RCC) —a tumor grade given to predict how fast the tumor is likely to grow and spread. 

In the patients, the clinical tumor size was 2.84 cm in patients with high-grade pathology and 2.56 cm in patients with low-grade pathology. The difference in size is statistically significant —a larger tumor size was associated with 62% increased odds of high-grade pathology.

The study also found that male patients had a 66% increased odds of high-grade pathology compared to female patients.

The study authors wanted to note the parallels with regards to an increased focus on the use of renal mass biopsies and surveillance of small renal masses, the confirmation of size to grade correlation allows urologists to predict more accurately which masses are appropriate to treat versus watching.

Understanding Your Pathology Report

When it comes to the diagnosis of cancer, pathologists work closely with physicians and specialists to diagnose and "grade" tumors. A tumor grade analyzes how abnormal the tumor cells and tissue look under a microscope and is an indicator of how quickly the tumor is likely to grow and spread.

Listen to Dr. David Samadi talk with Dr. Michael Misialek on the role of pathology in diagnosing prostate cancer.

It's important to note that the tumor grade is not the same as the stage of the cancer. The stage refers to the size and/or the reach of the original tumor and whether or not cancer cells have spread in the body.  Determining the stage of the cancer stems from factors such as location of the primary tumor, size, spread of cancer to nearby lymph nodes and number of tumors present.

The following tumor grade system is generally used:

• GX: Grade cannot be assessed (undetermined grade)
• G1: Well differentiated (low grade)
• G2: Moderately differentiated (intermediate grade)
• G3: Poorly differentiated (high grade)
• G4: Undifferentiated (high grade)

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Many patients who have been diagnosed with cancer and presented with their options, rarely understand how to read and interpret their pathology report. Of course, it's important to have a specialist that explains all the components  but it's also critical that you know how to read that report as well. 

Pathologists are doctors who examine cells, tissues, and body fluids to diagnose cancer and other diseases. When your doctor performs a biopsy, the pathologist will then examine the sample of your tissue to determine if cancer is found. The pathologist makes the diagnosis, writes the pathology report, and assists with your treatment along with your other doctors. More than 70 percent of all decisions about your diagnosis, treatment, hospital admission, and discharge rest on the pathology report.

Typically, a surgical pathology report is divided into a minimum of four to five sections:

• Patient Identifiers and Clinical Information
• Specimen Section
• Gross Description
• Microscopic Description
• Diagnosis

In summary, the surgical pathology report represents a description, which includes the location of the specimen and what your specimen looks like both with the naked eye and under microscope examination. Your pathologist will integrate all the clinical information about you into the pathology report to make a pathologic diagnosis and will consult with your other doctors regarding your treatment and care.

We found a detailed, comprehensive resource here to dive deeper into analyzing your pathology report. 

Other resources:

Breast Cancer: Pathology Report

Prostate Cancer: Pathology Report