A look back at Jimmy Carter's health journey and thoughts on aging

Former President Jimmy Carter, who is receiving hospice care at home after a series of short hospital stays, has had several health issues in recent years.

At 98 years old, Carter is the oldest and longest-lived U.S. President, telling People Magazine in 2015, when he was 95, that he never expected to be alive for as long as he has.

Here are some of the recent health challenges that Carter has faced:

Surgery on his liver

Carter underwent elective surgery on Aug. 2, 2015, at Emory University Hospital to remove a small mass in his liver, the Carter Center announced at the time.

While the surgery was successful and doctors said he would make a full recovery, the surgery revealed further health challenges for the former president.

2015 cancer diagnosis

On Aug. 11, 2015, Carter said that the surgery on his liver revealed that he had cancer and it spread to other parts of his body.

"I will be rearranging my schedule as necessary so I can undergo treatment by physicians at Emory Healthcare," he said in a statement through his organization.

There is a history of cancer in Carter's family. His mother died of breast cancer. His father, two sisters and brother all died of pancreatic cancer.

Doctors discovered that Carter had melanoma, one of the most common cancers affecting men and women in the U.S. and the most dangerous form of skin cancer.

Melanoma has a very high risk of metastasizing throughout the bloodstream or lymphatic system and to other body parts.

The 39th president said at an Aug. 20, 2015 press conference, that an MRI of his head and neck revealed that the cancer had spread to four different parts of his brain.

Carter, who was 90 years old at the time, said that when he discovered that the cancer had spread, he thought he didn't have much time left, which didn't alarm him.

"I just thought I had a few weeks left, but I was surprisingly at ease," Carter said. "I've had a wonderful life. I have thousands of friends…so I was surprisingly at ease, much more so than my wife was."

At the press conference, Carter said that despite the ease of knowing he lived a full life, he would follow his doctors' recommendation to ensure he "extends" his life as long as he can.

He underwent surgery, radiation therapy and cancer treatment called immunotherapy to fight the disease.

Carter received treatments between August 2015 through February 2016.

In December 2015, responding well to treatment, Carter said MRI scans showed that there were no longer any signs of spots of melanoma on his brain, nor did any new ones develop.

The former president announced to his church in March 2016, that doctors stopped his treatment after seeing no signs of tumors.

According to experts, the successful treatment was likely primarily due to the drug pembrolizumab, which targets cancer by ramping up the body's immune system. The U.S. Food and Drug Administration approved the treatment in 2011.

Dehydration at Habitat for Humanity

On July 13, 2017, the 2002 Nobel Peace Prize recipient was taken to the hospital for observation after becoming dehydrated while building homes in the hot sun at a Habitat for Humanity site in Winnipeg, Canada.

Carter was back at the work site the next day following his discharge from the hospital, the Carter Center announced.

Falls at his Georgia home

Carter fell at his Plains, Georgia, home as he was leaving to go turkey hunting, breaking his hip, his organization announced in May 2019.

The Grammy Award winner had hip replacement surgery at Phoebe Sumter Medical Center in Americus, Georgia, on May 13, 2019.

"President Carter said his main concern is that turkey season ends this week, and he has not reached his limit," the Carter Foundation said. "He hopes the State of Georgia will allow him to rollover the unused limit to next year."

A few days later, the Carter Center announced that he would be undergoing physical therapy from the surgery and recovering at home.

On Oct. 6, 2019, Carter fell at his home in Georgia. He ended up getting stitches above one of his eyebrows.

A few weeks later, on Oct. 22, 2019, the former president fell again at his home. He was admitted to the hospital and treated for a minor pelvic fracture, the Carter Center said.

Carter had surgery on Nov. 12, 2019, to relieve pressure on his brain caused by bleeding because of the falls at his home. According to the Carter Center, there weren't any complications from the surgery.

At-home hospice care

On Saturday, The Carter Center announced that the former president is receiving hospice care at home, where he is expected to spend his final moments with his loved ones, rather than seek further medical treatment.

"He has the full support of his family and his medical team," the Carter Center said in a statement. "The Carter family asks for privacy during this time and is grateful for the concern shown by his many admirers."

Despite the health challenges in recent years, Carter credits his marriage to his wife, former first lady Rosalynn Carter, for his longevity.

"It's hard to live until you're 95 years old," he told People Magazine in 2019, a few weeks after his second fall. "I think the best explanation for that is to marry the best spouse, someone who will take care of you and engage and do things to challenge you and keep you alive and interested in life."

ABC News' Meredith Deliso, Julia Jacobo, Dr. Chantel Strachan and Gillian Mohney contributed to this report.