Dave Coulier, 65, announced on Tuesday that he has stage 3 non-Hodgkin lymphoma.
The actor and comedian, best known for his role as Joey Gladstone in "Full House" from 1987 to 1995, said he was diagnosed in October after experiencing an upper respiratory infection caused by major swelling in his lymph nodes.
"Three days later, my doctors called me back, and they said, ‘We wish we had better news for you, but you have non-Hodgkin lymphoma, and it's called B cell, and it's very aggressive,'" he told People.
'FULL HOUSE' STAR DAVE COULIER DIAGNOSED WITH 'VERY AGGRESSIVE' CANCER
Non-Hodgkin lymphoma (also known as non-Hodgkin’s lymphoma, NHL or lymphoma) is a blood cancer that originates in the white blood cells (lymphocytes) that are part of the body’s immune system, according to the American Cancer Society (ACS).
Every year, more than 80,000 Americans are diagnosed with NHL.
"Non-Hodgkin lymphomas are a diverse group of white blood cell cancers that can vary greatly in terms of how aggressive or indolent they are," Dr. Joshua Strauss, an attending hematologist and medical oncologist at Advanced Care Oncology and Hematology Associates of the Atlantic Medical Group in Morristown, New Jersey, told Fox News Digital.
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Patients with aggressive types of NHL may develop rapidly growing masses that they can feel, or they may experience more general symptoms, such as fevers, night sweats and unintentional weight loss, noted Strauss, who has not treated Coulier.
An important part of diagnosis is determining what type of lymphoma the patient has, according to the ACS.
"The type of lymphoma depends on what type of lymphocyte is affected (B cells or T cells), how mature the cells are when they become cancerous and other factors," the organization states on its website.
Like other cancers, lymphomas are assigned a stage, from 1 to 4.
People with stages 1 and 2 have "limited disease," according to Strauss, while patients with stages 3 and 4 have "advanced disease," where the disease has spread to multiple areas of the body.
"However, as opposed to some other cancers, prognosis in NHL is more affected by histopathology, which is the particular subtype as determined by the appearance of the cancer under the microscope," the doctor said.
Depending on the subtype, some patients with stage 3 disease can have an "excellent prognosis," Strauss said, with recent advances in treatment improving outcomes.
Aggressive non-Hodgkin lymphoma is typically treated with intravenous chemo-immunotherapy.
"This is a cocktail of various chemotherapy drugs combined with an immune treatment that attacks the cancer cells while trying to spare normal cells," Strauss said.
After several months of treatment, doctors typically use imaging to determine whether any cancer remains.
Coulier revealed in the "Full House Rewind" podcast that he started chemotherapy two weeks after his diagnosis, and preemptively shaved his head.
While anyone can be diagnosed with NHL, there are several known risk factors.
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"People with autoimmune diseases or those who take medications to suppress the immune system may be at higher risk of developing NHL over time," Strauss said.
Certain infections, such as HIV and Epstein-Barr infection, as well as exposure to chemicals such as pesticides, may increase risk, the doctor warned.
"While NHL can occur at any age, risk increases as we get older," he said.
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The cancer type has also been associated with smoking and obesity, Strauss said — "so quitting smoking and maintaining a healthy weight may be protective."
Stephanie Giang-Paunon contributed reporting.