Former President Joe Biden’s diagnosis of an aggressive, stage-4 prostate cancer has reignited a long-simmering medical debate: When should men get screened for prostate cancer? For decades, doctors have wrestled with how often to screen men for the disease and when to start and stop.

It’s aggressive. The cells have an ugly, disordered appearance under a microscope. Pathologists gave them a Gleason score of 9 (out of 10) for their likelihood to advance quickly. The cancer has already moved from Biden’s prostate to his bones, which means it cannot be cured — only controlled with drugs.

People from all over the country sent encouragement to the 46th president after he revealed his cancer diagnosis.