Shortness of Breath & Radiation Pneumonitis

This page is for people who have had radiation to the chest and notice trouble breathing. It covers warning signs, possible causes, and what may help.

New or worsening shortness of breath after chest radiation is never a "wait and see" symptom. Call your cancer care team right away, day or night, even if it seems mild.

Call 911, or your local emergency number, right away for any of these signs.

• Shortness of breath that starts all at once, is severe, or does not get better with rest.
• New wheezing that makes it hard to breathe.
• Trouble speaking in full sentences because you are so short of breath.
• Chest pain, tightness, or pressure that starts suddenly, is severe, lasts more than a few minutes, or goes away and comes back.
• Dizziness or weakness that makes you feel like you might pass out.
• Confusion, trouble thinking clearly, or being hard to wake.
• Coughing up a large amount of blood along with shortness of breath, or substantial bleeding of any kind.
• Vomiting blood or coffee-ground material, or black tarry stool.

Source: American Cancer Society.

Call your cancer care team right away, day or night, for these signs. If you are on chemotherapy, a fever of 100.4°F (38°C) or higher, chills, or any sign of infection needs the same right-away call. A normal temperature is not a reason to wait.

• More shortness of breath than usual with routine activities.
• New wheezing that is not blocking your breathing.
• Breathlessness while speaking, but you can still finish your sentences.
• Brief, mild chest discomfort that goes away. Call 911 if it comes back.
• Coughing up yellow, green, or blood-tinged mucus.
• More restlessness or anxiety along with the breathing change.

One possible cause is radiation pneumonitis: inflammation of the lung tissue caused by radiation. MedlinePlus calls it potentially treatable and asks you to tell your provider if you notice it.

MedlinePlus describes the pattern to watch for. "After your treatment is over, if you notice a dry cough and worsening shortness of breath, this could be a side effect of radiation treatment to the lungs called radiation pneumonitis. Make sure you let your provider know if you have this, as it is potentially treatable."

Two features matter most: a dry cough, and shortness of breath that is getting worse.

During or shortly after your radiation course, watch for a different pattern too. MedlinePlus notes: "You may develop a fever, more mucus when you cough, or feel more out of breath." Their advice is clear. "Contact your provider if you have pain that doesn't go away, a fever, severe vomiting or diarrhea, cough, or blistering of the skin."

The American Cancer Society gives the same advice for radiation side effects in general. "If you notice any side effects, talk to your doctor right away so they can be managed."

The National Cancer Institute, or NCI, lists these possible side effects of radiation therapy to the chest.

• Fatigue.
• Hair loss.
• Skin changes.
• Throat problems, such as trouble swallowing.
• Cough.
• Shortness of breath.

NCI says healthy cells damaged by radiation usually recover within a few months after treatment is over. But NCI warns that other side effects may show up months or years later. These are called late effects. Its advice is simple. "Ask your doctor or nurse which late effects you should watch for."

NCI's summary on cardiopulmonary syndromes, meaning heart and lung complications, lists several causes of breathlessness in people with cancer.

• A tumor blocking an airway.
• Fluid around the lung or heart.
• Blood clots.
• Infection.
• Radiation damage to the lungs.
• Weakened heart muscle caused by chemotherapy.

The cause changes the treatment. That is why your team needs to assess you rather than guess.

Postradiation bronchiolitis obliterans. NCI describes this as a rare complication. It occurs in 0.8% to 2.9% of women who receive radiation therapy for breast cancer. NCI says patients are usually treated with corticosteroids.

Immunotherapy-related pneumonitis. If you also received a checkpoint inhibitor, a type of immunotherapy, NCI states that pneumonitis linked to these drugs "is uncommon but can be serious or life-threatening." It can start anywhere from several days to over a year after treatment.

NCI lists these tools for finding the cause.

• A physical exam.
• Health history.
• Functional assessment.
• Chest x-rays.
• CT scans.
• Blood counts.
• Oxygen saturation tests.

NCI says treatment depends on the cause. Ask your radiation oncologist what they would use for radiation pneumonitis.

These steps do not treat the underlying cause. The American Cancer Society, or ACS, lists them as ways to ease the feeling of breathlessness.

• Sit up, or raise your upper body by elevating the head of your bed or using pillows.
• Try pursed-lip breathing: inhale deeply through your nose and exhale slowly through puckered lips.
• Loosen tight clothing. Try relaxation or distraction, such as music or reading.
• Avoid smoking, secondhand smoke, and allergens like dust and pet dander.
• Ask your doctor about medicines for the symptom itself.

These patient-facing federal and cancer-organization sources leave some questions open. They do not give a precise onset window for radiation pneumonitis. They do not give a steroid dose or duration. NCI says only that late effects "may show up months or years after radiation therapy is over." Ask your radiation oncologist what window they expect, based on the dose and lung volume you received.

• National Cancer Institute: Radiation Therapy Side Effects. https://www.cancer.gov/about-cancer/treatment/types/radiation-therapy/side-effects
• National Cancer Institute: Cardiopulmonary Syndromes (PDQ) — Patient Version. https://www.cancer.gov/about-cancer/treatment/side-effects/cardiopulmonary-pdq
• National Cancer Institute: Cardiopulmonary Syndromes (PDQ) — Health Professional Version. https://www.cancer.gov/about-cancer/treatment/side-effects/cardiopulmonary-hp-pdq
• MedlinePlus (National Library of Medicine): Chest radiation - discharge. https://medlineplus.gov/ency/patientinstructions/000057.htm
• American Cancer Society: Shortness of Breath. https://www.cancer.org/cancer/managing-cancer/side-effects/shortness-of-breath.html
• American Cancer Society: Radiation Therapy for Esophageal Cancer. https://www.cancer.org/cancer/types/esophagus-cancer/treating/radiation.html