Former President Jimmy Carter, who is battling malignant brain cancer, got good news when he learned the disease has stopped spreading and is “responding well to treatment,” the Carter Center in Atlanta said in a statement on Tuesday.

Carter, 91, revealed in August that he had been diagnosed with melanoma, a deadly form of skin cancer, which was in an advanced stage and had spread to his brain.

He received the diagnosis following surgery for liver cancer, saying at that time that he had thought all of the disease had been removed but subsequent tests had revealed it had spread. 

Although malignant brain cancer has a poor prognosis, Carter’s doctors at Emory University’s Winship Cancer Institute were upbeat. They said that the cancer was treatable, and that Carter would immediately begin radiation treatment as well as receive a new immunologic treatment called Keytruda, which the FDA approved just last year.

The Carter Center issued the statement saying that the former president had received “good news” from his Winship Cancer Institute doctors.

“They tell him that recent tests have shown there is no evidence of new malignancy, and his original problem is responding well to treatment,” the statement said.

Carter will continue to undergo further testing, the center also said.