Is it the flu or cancer? The two diseases share many common symptoms

The flu and some cancers share many common symptoms. Learn what to do if your flu symptoms worsen or do not get better after two weeks.

After weeks of suffering from fatigue and shortness of breath in the fall of 2016, Hunter Brady went to the doctor, who diagnosed him with the flu. But when the 16-year-old’s prescribed treatment didn’t relieve his symptoms, a second opinion revealed the Florida boy had stage 4 Hodgkin lymphoma. Fatigue, chills, fever, weight loss, swollen lymph nodes and persistent cough are common symptoms of the flu. But they also are common symptoms of some cancers, especially hematologic malignancies, such as lymphoma and leukemia.

As flu season approaches, there may be rare cases when patients who think they have the flu are later diagnosed with cancer, says Mashiul Chowdhury, MD, Chief of Infectious Diseases at Cancer Treatment Centers of America® (CTCA), though he says there is no need for anyone to be alarmed, stressing that the occurrences are rare. “The symptoms of the flu or an infection often are similar to symptoms of cancer because some of the mechanisms are quite similar,” Dr. Chowdhury says. “Your immune system is down. So, you feel a malaise, you have a fever. Then you go to get a chest X-ray and you get a bad surprise—cancer.”

Cases of common symptoms

While it is rare for cancer to be inaccurately diagnosed as the flu, several cases have made headlines. For instance: 

  • In 2012, a women who fought through weeks of flu symptoms was later treated at the Mayo Clinic in Jacksonville, Florida, for thyroid cancer.
  • In 2016, Jaime Luis Gomez, known as rapper Taboo and a former member of pop group The Black Eyed Peas, said in an interview that he thought his pain, headaches and shortness of breath were brought on by the flu. He was later diagnosed with stage 2 testicular cancer.

The inaccurate diagnoses should not cause panic. Dr. Chowdhury says patients who have been diagnosed with the flu or have flu-like symptoms should not be alarmed or immediately think they have something other than the flu. But if symptoms worsen or do not get better after two weeks, they should see a doctor. “If you have an infection, and this is especially important for older people, and it lasts longer than the average period, then there should be concern,” Dr. Chowdhury says. “Then you need to go tell your doctor this is not going away.”

Cancer may increase flu risk

It’s also important to know that patients who are undergoing cancer treatment may be at a higher risk for catching the flu, because their immune system may be weak. As flu season approaches, here are some tips for cancer patients and their caregivers that may help reduce the risk of getting sick:

  • Get the flu vaccine. The American Cancer Society says flu vaccines are safe for cancer patients. But check with your doctor first.
  • Make sure your family members and caregivers also are vaccinated.
  • Avoid crowds or wear a mask if you must be in a large group.
  • Wash hands frequently.
  • If you think you may have been exposed to the flu, talk to your doctor as soon as possible. A doctor may choose to prescribe prophylactic antibiotics that may ease symptoms or prevent the flu from developing.

Learn more about the flu-like symptoms associated with leukemia, Hodgkin lymphoma and non-Hodgkin lymphoma.