By Kathleen Doheny
WebMD Health News
Reviewed by Michael W. Smith, MD
Aug. 13, 2015 -- Doctors treating former President Jimmy Carter are in the process of trying to figure out what type of cancer he has and where it has spread.
The 90-year-old humanitarian issued only a brief statement on Wednesday, saying he had cancer that has spread to other parts of his body. He also said he would seek treatment at Atlanta's Emory University.
Although the disease was discovered during surgery to remove a mass on his liver, that does not mean the cancer started there -- the liver is often a place for cancer to spread.
WebMD turned to two oncology experts to ask what may lie ahead for the former president. Neither doctor has treated Carter.
Q: How do doctors find out where a cancer started?
It takes detective work.
"Usually the way we know where something started is through our pathologist," says Dale Shepard, MD, a medical oncologist at Cleveland Clinic. "If someone has an abnormality in the liver, the tumor may have started in the liver, or the tumor may have originated somewhere else and spread to the liver. We would need to get a biopsy of that tissue," he says.
The biopsy will help determine if the tumor has cells that came from liver tissue or tissue from another area of the body where the cancer started.
Doctors may also use scans to find the cancer, depending on where they think it is, says Vincent Chung, MD, a medical oncologist at City of Hope Comprehensive Cancer Center. "If you see sites outside the liver [where cancer is lurking], you will potentially go searching in those areas, with an upper endoscopy or colonoscopy [for instance].''
Q: Is there a point where finding out where the cancer started is not possible?
"There absolutely are cases where we cannot determine where a metastatic lesion came from," Shepard says. Cells may lose the unique characteristics that show where they come from. "This is actually surprisingly common."
Q: If you can't find out where a cancer started, how might that impact treatment?
"If you have an unknown primary cancer, we treat usually with two different chemotherapy drugs that cover a wide range," Shepard says.
"There are chemotherapy regimens that can be used to slow down the growth," Chung agrees.
Q: Would regular cancer screening tests be done on a 90-year-old?
"Guidelines would suggest not doing cancer screenings at that age," Shepard says. After a certain age, ''it's more likely that people would die of another cause rather than the cancer you find," he says. But ''because we don't do screenings for cancer for older people does not mean we don't treat older people with cancer," Shepard adds.
In treating patients, he says, doctors think about ''functional'' age, not actual age. "There are patients who are 50 or 60 who are far more debilitated... that I would hesitate to give chemotherapy to. But I see 80-year-olds who are running large corporations and very active and very able to take chemotherapy. I think that's important."
Treatment of cancer that has spread is often focused on symptom management, Shepard says. For instance, ''if a person develops a metastasis in an arm or leg and it is painful, we sometimes do radiation in that area to improve pain control. When we think about treatment for disease that has spread, the primary treatment becomes something like chemotherapy because it treats the entire body.'' Surgery would not typically come into play, he says.
Q: Carter told the media in 2007 that he used to get scans twice a year due to a family history of pancreatic cancer. He said he'd stopped getting them regularly, opting instead for "extensive blood work" and physical exams. With frequent health checks, how could cancer spread?
"Different cancers have different growth rates," Chung says. "Certain cancers are much more aggressive than others. The caveat here is, we don't know how extensive his disease is."
"Cancer can sometimes develop very quickly," Shepard says. "We don't know what he is ultimately going to be found to have."
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SOURCES: Statement, The Carter Center, Aug. 12, 2015. Dale Shepard, MD, medical oncologist, Cleveland Clinic Foundation. Vincent Chung, MD, medical oncologist, City of Hope Comprehensive Cancer Center, Duarte, CA.
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