The former president has remained optimistic despite his diagnosis, previously telling CNN "the expectation is we're going to be able to beat this."

Former President Joe Biden is going through a new phase of treatment for prostate cancer, according to multiple media outlets. In comments first reported on by NBC News, a spokesperson said Biden is currently undergoing radiation therapy along with hormone treatment.

The radiation therapy is set to last five weeks, a source told NBC.

Biden was already taking a pill form of hormone medication for prostate cancer, which he was diagnosed with in May. He received the diagnosis after visiting doctors because of urinary symptoms, and they discovered a nodule on the former president's prostate.

At the time, Biden's office said the cancer was a "more aggressive form of the disease" that spread to his bones. However, it also appeared to be hormone sensitive, "which allows for effective management."

Speaking to CNN two weeks after his diagnosis, Biden said, "the expectation is we're going to be able to beat this." He added, "It's not in any organ, it's in -- my bones are strong, it hadn't penetrated. So, I'm feeling good."

Prostate cancer, according to the Mayo Clinic, is one of the most common forms of cancer. It's known to grow slowly, and if caught early, is most often treatable.

In September, Biden's spokesperson confirmed he had surgery to remove skin cancer lesions days after he was seen leaving church with a scar on his forehead. The spokesperson confirmed to The Associated Press that Biden, 82, had Mohs surgery. The procedure involves cutting away thin layers of skin until cancerous cells are totally removed.