Former President Jimmy Carter said Sunday his cancer is gone.

Carter said in a statement that his most recent MRI brain scan did not reveal any signs of the original cancer spots or any new ones and that he’ll continue his treatment.

Carter, 91, initially made the announcement near the beginning of the Sunday School class he was teaching at Maranatha Baptist Church in Plains, a close friend and fellow church member said.

“He said he got a scan this week and the cancer was gone,” Jill Stuckey said by phone from Maranatha, where Carter was still in the midst of teaching to about 350 people, many of them visitors. “The church, everybody here, just erupted in applause.”

Even one of Carter’s closest friends had no idea the news that was coming — which only added to her sense of gratitude as the news filled the little church.

Watch: Carter tells church he’s cancer free

“It’s like getting the biggest Christmas gift that you could ever want,” said Jan Williams, who spends the hour before Carter’s class humorously instructing visitors on the do’s-and-don’ts of being around their famous teacher. “This week was just horrible in the world in terms of all the bad things happening. How wonderful in the midst of all this to get such wonderful, encouraging news.”

Carter’s grandson, James Carter, confirmed that a recent test showed his grandfather was cancer-free.

“There’s no cancer in his body at this point,” said James Carter. “He’s not going to stop doing the treatment, but at this point, there’s no cancer. It’s incredible news.”

“See?” he added. “I knew he wasn’t really human.”

Or as his friend, Williams, put it: “I never felt God was through using Jimmy Carter yet. He’s done what the doctors told him to do, and what an example that is for the rest of us.”

Carter’s doctors at Emory University’s Winship Cancer Institute, deferred all requests for comment to the Carter Center on Sunday. Meanwhile, one expert who is not involved in the former president’s treatment cautioned that this latest bit of good news doesn’t mean he is cured or is totally cancer-free.

“It doesn’t mean that there is no cancer in his body; it means that there is no indication that they can find cancer for the present,” said Dr. Len Lichtenfeld, deputy chief medical officer for the Atlanta-based American Cancer Society, who stressed he was speaking about cancer in general.

While the scans of Carter’s brain and liver show no signs of the disease, cancerous cells could still be in his bloodstream, said Lichtenfeld. Still, he said, the news is encouraging for Carter.

“The President has done exceptionally well. There are still many patients with melanoma who don’t have this outcome,” said Lichtenfeld. “He’s in the best possible place.”

And yet, only a few years ago, Stage IV melanoma was tantamount to a death sentence, and it still is a very difficult disease for many.

Carter: “So I have good news.”

Outcomes for the illness began to change as few as five years ago, when drugs that rally the body’s own immune system to fight the disease began to show promise.

And, one of Carter’s physicians at Winship Cancer Institute of Emory University, Dr. David Lawson, happened to be one of several researchers at sites around the country who were studying the effect of these drugs.

These so-called immunotherapeutic drugs have shown great promise in treating melanoma. Lawson was involved in studies that resulted in approval of the drug Yervoy in 2011. Since then, several others also have been approved by the FDA, including the drug, pembroluzimab, that Carter has been treated with since August.

Carter said in August that doctors had found four small melanoma lesions on his brain. The discovery followed the removal of a lesion on his liver that took about ten percent of the organ. He said he would receive four drug treatments, along with radiation therapy, and that he would cut back significantly on his schedule.

At a Habitat for Humanity build in Memphis last month, Carter said he had completed his round of four treatments and was feeling good. A week later, the Carter Center released what it termed a “good news” statement, in which it said his doctors at Emory University’s Winship Cancer Institute had told their famous patient that recent tests had shown no evidence of new malignancy and that he was “responding well to treatment.”

(A spokeswoman for Emory and Winship said Sunday that all inquiries were being referred to The Carter Center and no experts would be available to discuss this lastest news.)

Back in Plains, meanwhile, no one appeared to be holding back. The mood around town was one of “elation,” said Plains Trading Post owner Phil Kurland. Someone who’d been at Maranatha for Sunday School didn’t stay around for the church service, and instead came into the political memorabilia store on Main Street to relate what Carter had said. And people kept streaming in later in the day to express their wonder, and in some cases, slight apprehension.

“Apprehension in that they’re hoping (the news) stays good,” Kurland explained. “Certainly, though, the feeling is it’s a happy surprise.”

Even before this latest piece of good news, the former president was upbeat and active. Another Carter grandson, former state Sen. Jason Carter, said Wednesday during an address to the Atlanta Press Club that his grandfather was doing well physically, emotionally and mentally. Jason Carter took the job as the chair of the Carter Center after his grandfather said his cancer would force him to take a step back from his day-to-day duties.

“There’s been no evidence of that at all,” the younger Carter quipped.

Staff writer Greg Bluestein contributed to this article.