Leading medical experts have weighed in on President Joe Biden’s recent diagnosis of aggressive prostate cancer, which had already spread to his bones by the time it was discovered. Many were surprised the cancer wasn’t caught earlier, especially given Biden’s regular access to top medical care.

Doctors say that men over 70 are often not screened for prostate cancer due to potential side effects from treatment and shorter life expectancy. This could explain why Biden, 82, was not tested routinely. Experts believe his last PSA test may have been before he became president.

Prostate cancer is highly treatable if caught early, but aggressive forms can develop even with low PSA levels and without clear symptoms. Some doctors note that Biden’s other health issues—like high cholesterol and sleep apnea—might have diverted attention from cancer screening.

Although the exact stage of Biden’s cancer is unknown, it likely progressed over several years. Despite the seriousness of the diagnosis, experts say that older patients with metastatic prostate cancer often respond well to modern treatments, and Biden could still live many more years with proper care.