Managing a cancer diagnosis requires close attention to your overall health, including protecting yourself from infections. Although tuberculosis (TB) is relatively rare in the United States, cancer can put you at a higher risk of contracting TB. This is because cancer can weaken your immune system. Understanding how this infection behaves, how it interacts with cancer therapies, and what steps you can take will help keep you safe throughout your care.
What is tuberculosis (TB)?
TB is an infectious disease caused by a bacterium called Mycobacterium tuberculosis. It mainly affects the lungs but can also spread to other parts of the body, including the lymph nodes, brain, kidneys, and spine. TB spreads through tiny droplets in the air when an infected person coughs, sneezes, or speaks. TB exists in two primary stages:
Latent TB infection (LTBI): The bacteria lives in the body in an inactive state. You do not feel sick, cannot spread the bacteria to others, and have no symptoms. However, the bacteria can "wake up" (reactivate) if your immune system becomes weakened.
Active TB disease: The bacteria actively multiply, causing illness and symptoms. Active TB can spread to others if it infects the lungs.
Common symptoms of active lung TB include:
A persistent cough lasting longer than 3 weeks
Chest pain
Coughing up blood or sputum
Unexplained weight loss and loss of appetite
Fever, chills, and night sweats
Fatigue or severe tiredness
How common is tuberculosis in the United States?
Compared to global figures where over 10 million people contract TB annually, TB is relatively rare in the United States. According to CDC surveillance data, the U.S. records roughly 9,000 to 10,000 cases of active tuberculosis per year (about 3 cases per 100,000 people). However, millions of Americans carry latent tuberculosis without knowing it. Because cancer treatments suppress the immune system, cancer patients face a much higher risk of latent TB turning into active disease.
What are risk factors for having tuberculosis?
For people with cancer, key risk factors that increase the likelihood of getting TB or reactivating a latent infection include:
Weakened immune system. This could be caused by the cancer itself or treatments like chemotherapy, radiation, and corticosteroids.
Treatment with immune checkpoint inhibitors (ICIs). While advanced immunotherapies strengthen T-cell responses against tumors, they can disrupt immune signals like TNF-alpha. This can destabilize protective TB structures (granulomas) and cause active infection.
Other conditions. Having chronic obstructive pulmonary disease (COPD), asthma, or old lung scarring increases susceptibility to lung infections.
Age. Older adults (aged 60 and older) are more likely to be exposed to TB.
Location and travel habits. People born in or frequently traveling to areas where tuberculosis is common face higher exposure rates.
Lifestyle factors. Smoking tobacco, heavy alcohol use, and malnutrition significantly compromise respiratory defenses.
What is tuberculosis chemotherapy?
Many patients are surprised to hear doctors refer to anti-TB therapy as "TB chemotherapy."
Historically and medically, the term chemotherapy simply refers to treating disease with chemical agents or medications to eliminate or stop the growth of targeted cells whether those cells are cancer cells or invading bacteria.
The treatments share several practical similarities like both therapies require ongoing blood work to monitor liver function, metabolic balance, and potential medication interactions.
Can TB and lung cancer be misdiagnosed?
In a 2022 study published in the International Journal of Medical Microbiology, researchers explored how TB infection interacts with host tissue to potentially drive cell changes similar to cancer.
Research showed that TB infection and lung cancer regulate many of the same key genes involved in cell cycle regulation and cell division (such as BIRC5, BRCA1, and CHEK1). It also observed that bacteria toxins and chronic inflammation caused by TB can damage cellular DNA and inhibit tumor suppressor pathways, potentially creating an environment where abnormal cells grow unchecked.
The study concluded that TB and lung cancer often mimic each other on chest scans and blood work. Misdiagnosing lung cancer as TB leads to delayed cancer care, while misdiagnosing TB as cancer can expose a patient to unnecessary toxic treatments while the infection worsens.
Does tuberculosis increase the risk of lung cancer?
A more recent review published in the journal Cancers (2025) focused on the relationship between TB and lung cancer. They found that people with a history of TB have a 1.5 to 3-fold increased risk of developing lung cancer. The highest risk occurs within two years after diagnosis.
How do cancer treatments affect tuberculosis?
In the same study, they found thatImmune checkpoint inhibitors (such as PD-1/PD-L1 inhibitors) can trigger inflammatory responses that destabilize dormant TB bacteria. This can lead to sudden reactivation during cancer therapy.
Can tuberculosis medications impact cancer care?
In the same study, researchers found that the TB medication rifampicin speeds up liver enzyme activity (CYP3A4). This can rapidly lower the levels of oral cancer drugs in the bloodstream and make cancer therapies less effective.
How can I prevent tuberculosis?
Ask your healthcare provider about getting tested for latent TB before starting chemotherapy, radiation, or immunotherapy. If you have symptoms that may seem like TB, report them immediately. For example, if you experience a new cough, unexplained fevers, night sweats, or unexpected weight loss, notify your care team right away rather than assuming it is a side effect of cancer treatment.
Families should support patients by avoiding exposure to people with active respiratory illnesses and ensuring proper home ventilation.
TB and cancer are complex conditions, but proactive screening, timely diagnosis, and coordinated care make both manageable. Communicating openly with your healthcare team about past infections or new symptoms ensures your cancer treatments remain safe and effective.
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Sources:
Tuberculosis and Lung Cancer: Insights from a Narrative Review
Tuberculosis and risk of cancer: A systematic review and meta-analysis
