A patient undergoes prostate Cancer brachytherapy at the Nairobi Hospital. [File, Standard]

Former US President Joe Biden's illness has renewed public discussion about what happens when prostate cancer spreads to the skeleton.

Biden's prostate cancer has metastasised to his bones, which is described as painful and debilitating.

The discussion comes as experts raise concerns that many Kenyan men are diagnosed with prostate cancer at an advanced stage, when the disease may already have metastasised.

Dr Catherine Nyongesa, a consultant clinical and radiation oncologist and Director of Medical Services at Kenyatta National Hospital, explains that bone is the most common site of metastasis for advanced prostate cancer.