WASHINGTON (AP) — Former President Joe Biden on Monday completed a round of radiation therapy treatment for the aggressive form of prostate cancer he was diagnosed with after leaving office, a spokesperson said.

Biden had been receiving treatment at Penn Medicine Radiation Oncology in Philadelphia, said aide Kelly Scully.

The 82-year-old Democrat left office in January, six months after he dropped his bid for reelection following a disastrous debate against Republican Donald Trump amid concerns about Biden's age, health and mental fitness. Trump defeated Democrat Kamala Harris, who was Biden's vice president.

In May, Biden's postpresidential office announced that he had been diagnosed with prostate cancer and that it had spread to his bones. The discovery came after he reported urinary symptoms.

Prostate cancers are graded for aggressiveness using what is known as a Gleason score. The scores range from 6 to 10, with 8, 9 and 10 prostate cancers behaving more aggressively. Biden’s office said his score was 9, suggesting his cancer is among the most aggressive.

Last month, Biden had surgery to remove skin cancer lesions from his forehead.