On Friday, two-time Academy Award winner Jane Fonda announced on Instagram that she’s been diagnosed with non-Hodgkin’s lymphoma. The 84-year-old said she has already started chemotherapy treatments.

According to Fox News, non-Hodgkin’s lymphoma (NHL) is a type of cancer that begins in the immune system. The immune system is designed to fight infection, but sometimes cancer can attack its white blood cells, called lymphocytes, and trigger NHL. The American Cancer Institute estimates that 763,401 Americans were living with this form of cancer in 2019. There are several subtypes of NHL, with diffuse large B-cell lymphoma and follicular lymphoma being the most common subtypes, says the Mayo Clinic.

Symptoms of NHL include:

• Swollen lymph nodes in the neck, armpits, or groin

• Abdominal pain or swelling

• Chest pain, coughing or trouble breathing

• Persistent fatigue

• Fever

• Night sweats

• Unexplained weight loss

The exact cause of NHL is not known, but it occurs when the old lymphocytes refuse to die and the body keeps creating new ones, resulting in an overabundance of lymphocytes. This oversupply crowds into your lymph nodes, causing swelling.

NHL most often begins in the B cells but could occur in T cells, according to the Mayo Clinic. Risk factors for the disease include medications that suppress the immune system, infection from certain viruses and bacteria, environmental chemicals, and advanced age.

After diagnosis by a physical exam, blood and urine tests, imaging tests and in some cases a lymph node biopsy among other diagnostic tools, a doctor determines the subtype of NHL and which treatments would be most effective. If the lymphoma does not appear to be aggressive and is growing slowly, doctors may adopt a wait-and-see treatment schedule with regular checkups.

If the NHL is aggressive and causes signs and symptoms, treatment options include:

• Chemotherapy, either orally or by injection to kill cancer cells. This is usually the first line of treatment for NHL.

• Radiation therapy. This option uses high-powered energy beams, such as X-rays and protons, to destroy cancer cells. If the cancer is slow growing and located in just one or two spots, this may be the only treatment needed.

• Targeted drug therapy. Targeted drug treatments focus on specific abnormalities within cancer cells. By blocking these abnormalities, these treatments kill cancer cells.

• Stem cell transplant. This treatment involves harvesting stem cells from the bone marrow or blood.  High doses of chemotherapy and radiation suppress bone marrow and the immune system. Then healthy bone marrow stem cells from the patient’s own body or from a donor are infused into the bloodstream where they travel to the bones and rebuild bone marrow, says the Mayo Clinic.

According to Fonda, she’s been “doing chemo for six months and am handling the treatments quite well.” The overall survival rate for NHL is 73.8% according to the National Cancer Institute.