Ethan Zohn, 'Survivor' Star, Says His Hodgkin's Lymphoma Has Returned: What Is It?

"Survivor" star Ethan Zohn has announced that his Hodgkin's lymphoma has returned, according to news reports.

Zohn, who won "Survivor: Africa," told People that he had been in remission from the cancer for 20 months until doctors found that it had returned on Sept. 14.

"It's localized in my lung area," Zohn, 37, told People. "But it's good that it's not all over my body."

Hodgkin's lymphoma, which is a cancer of lymph tissue, is much less common than the other lymphatic cancer, non-Hodgkin's lymphoma, according to the Mayo Clinic. Government data shows that there were 8,830 new cases of Hodgkin's lymphoma last year, and 1,300 deaths from the disease.

The disease is considered very curable when found early (and can even be curable when it's progressed to a more advanced stage), according to the A.D.A.M. Medical Encyclopedia. More than 90 percent of people with early-stage Hodgkin's lymphoma will go on to live for 10 or more years, and even if the cancer has progressed and spread, 90 percent of those people will go on to live for at least another five years.

There are two main types of Hodgkin's lymphoma -- the classical Hodgkin's lymphoma, and the nodular lymphocyte-predominant Hodgkin lymphoma, which is much rarer, according to the National Cancer Institute. Symptoms of the cancer include an enlarged spleen, lymph nodes or other tissues involved in the immune system, as well as weight loss, fever, fatigue and night sweats.

Hodgkin's lymphoma and non-Hodgkin's lymphoma are different in that in Hodgkin's lymphoma, there is the presence of a cell called the Reed-Sternberg cell, the Mayo Clinic reported. If this kind of cell isn't present, then the cancer is considered non-Hodgkin's lymphoma.

The exact cause of the disease, formerly known as Hodgkin's disease, is still unknown, the Mayo Clinic reported. But doctors and scientists do know that the cancer occurs when a DNA mutation occurs in one of the body's types of infection-fighting cells. The mutation spurs rapid cell division and gives them the ability to live on when the cells are supposed to die, which results in an accumulation of these cells, according to the Mayo Clinic.

Hodgkin's lymphoma is most common in people ages 15 to 35 and people over the age of 55. It's also more common in people with a family history of the disease, as well as men, according to the Mayo Clinic. People who have a weak immune system (whether from disease like HIV/AIDS or from immunosupressing drugs) or people who have been infected with the Epstein-Barr virus also have an increased risk of this kind of cancer.

Treatments for Hodgkin's lymphoma depend on the kind of lymphoma the person has and the severity of the cancer, according to the A.D.A.M. Medical Encyclopedia. Radiation therapy and chemotherapy, alone or together, are typically used to treat this disease, though if they don't work, a bone marrow transplant may also be conducted.

Previously, Zohn had undergone rounds of chemotherapy and a stem cell transplant in efforts to beat the cancer. This time around, People reported that Zohn began "smart" chemotherapy in October that targets cancerous cells, and will also undergo another stem cell transplant from one of his family members.

Stem cell transplants become an option for treatment of the disease when chemotherapy doesn't work, according to Fox Chase Cancer Center.

Fox Chase explains how the stem cell method works:

Immature blood cells (otherwise known as stem cells) are removed from the blood or bone marrow of the patient to be frozen and stored. Following therapy, the stored stem cells are given back to the patient. These reinfused stem cells grow into (and restore) the body's blood cells, which makes recovery more successful.

Zohn joins a list of other big names who have been diagnosed with a lymphoma in the past. Paul Allen, co-founder of Microsoft, was diagnosed with non-Hodgkin's lymphoma in 2009, and mohawked actor Mr. T -- whose real name is Laurence Tureaud -- was diagnosed with T-cell lymphoma in 1995.

Country music star Gene Autry died in 1988 of lymphoma at age 91 and Joseph Coors Sr., of the Coors beer family, died of lymphatic cancer at 85 in 2003.