Former President Joe Biden diagnosed with aggressive prostate cancer, doctor weighs in on risks and treatments

Former President Joe Biden announced he's been diagnosed with an aggressive form of prostate cancer. It comes just days after doctors revealed a mass had been found in his prostate gland. Dr. Ash Tewari, the chair of urology at Mount Sinai, joined us on 'The Nine' to discuss prevention and screening, treatments and who's most at-risk.