Joe Biden prostate cancer diagnosis: What a Gleason score of 9 means?

Former President Joe Biden has been diagnosed with an aggressive form of prostate cancer, his office announced. The 82-year-old was examined last week after he experienced urinary symptoms, according to a statement Sunday from spokesperson Kelly Scully. The cancer had metastasized to the bone.

“While this represents a more aggressive form of the disease, the cancer appears to be hormone-sensitive which allows for effective management,” Scully said. “The president and his family are reviewing treatment options with his physicians.”

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The press release noted a Gleason score of 9 (Grade Group 5) and metastasis to the bone. Below is an explanation of what a Gleason score of 9 means in the context of this diagnosis. 

What is a Gleason Score?

The Gleason score is a grading system used to assess the aggressiveness of prostate cancer based on the appearance of cancer cells under a microscope. It ranges from 6 to 10, with higher scores indicating more aggressive cancer. A score of 9 is among the highest, signifying a highly aggressive form.

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Score Breakdown: A Gleason score of 9 typically combines two patterns, such as 4+5 or 5+4, where the first number represents the most common cell pattern and the second the secondary pattern. Pattern 5 indicates the most abnormal, least differentiated cells, suggesting rapid cancer growth.

Grade Group 5: A Gleason score of 9 corresponds to Grade Group 5, the highest risk category, indicating a cancer that is likely to grow and spread quickly, per the American Cancer Society. 

Metastasis to Bone: The diagnosis includes bone metastasis, meaning the cancer has spread beyond the prostate to the skeletal system, a hallmark of advanced-stage (Stage IV) prostate cancer. This complicates treatment and worsens prognosis, per Mayo Clinic.

Source

Press Room May 18, 2025