Lung Cancer After Radiation: What to Know

Medically Reviewed by Jennifer Robinson, MD on August 04, 2022
Written by Stephanie Watson
5 min read

When you're in the middle of cancer treatment, your main goal is to control the disease. But you should also be aware of how each type of therapy might affect you now and in the future.

Radiation therapy uses high-energy X-rays to kill cancer. Getting it after surgery or on its own could slow your cancer's growth or stop it from coming back. But radiation to the chest might also raise your odds of lung cancer down the road, especially if you've smoked for many years. The good news is that the chance of this happening is low overall. Here’s what we know.

Radiation uses a beam of intense energy to damage the genetic material, or DNA, inside cancer cells. This damage stops cancer cells from dividing and causes them to die.

But over time, radiation can also damage the DNA in healthy cells and turn them into cancer. And because your lungs are in your chest, radiation for cancers in that area – like breast or lung cancer – can reach and damage cells in your lungs. If a cancer were to form, it would take a while for it to grow. Lung cancers often take 10 years or more to form after radiation therapy.

Your risk of lung cancer may be higher when you get radiation therapy to your chest to treat:

It's been hard for researchers to figure out the risk of lung cancer after radiation therapy. That’s because most of the studies were done many years ago with older radiation techniques that are no longer used. But a few studies have reported a higher chance of lung cancer with the newer radiation therapy techniques in use today.

A study of several thousand women from 1992 to 2012 found that those who had breast cancer and got radiation therapy were more likely to get lung cancer 20 years later than women who didn't have breast cancer. In real numbers, the risk was small -- 3% of women who had radiation therapy got lung cancer, compared to 2% of women who didn't have breast cancer.

You're more likely to get lung cancer after radiation therapy if you're a long-term smoker who kept smoking after cancer treatment. In one study, the risk of dying from lung cancer after radiation treatment for breast cancer was 4% for long-term smokers compared to 0.3% in nonsmokers.

Like radiation therapy, smoking also damages DNA. That's why smokers are already at high risk for many types of cancer.

The dose of radiation you get and the area that's exposed to radiation could affect your chance of getting lung cancer in the future. In general, your odds of lung cancer go up if you get higher doses of radiation and they're delivered closer to your lungs.

There are a few things that both you and your treatment team can do to lower your chances of lung cancer after radiation therapy:

Quit smoking. One of the most important things you can do to avoid lung cancer is to stop smoking if you do. Smoking is a major cause of lung cancer on its own. Continuing to smoke may raise your risk for lung cancer even more after radiation treatment.

Quitting takes time, but there are tools to help ease your cravings, including:

  • Nicotine replacement therapy patches, gums, and lozenges
  • Medicines like bupropion (Zyban) and varenicline (Chantix)
  • Online and in-person stop-smoking programs
  • Therapy and other forms of support

Ask your doctor for advice on the different methods to help you quit.

Get lung-sparing radiation therapy. Modern radiation therapies are designed to avoid damage to the lungs. Doctors can now map out the treatment area beforehand using 3D modeling. This allows them to deliver a more precise beam of radiation to your tumor.

A newer type of radiation called proton beam therapy aims a very precise beam of radiation at the tumor. This treatment can protect your lungs from damage, but it is expensive.

Accelerated partial breast radiotherapy treats smaller areas of the breast at one time to lower radiation exposure to the lungs. This treatment may be an option if you have a small, early-stage breast cancer.

Hold your breath. Ask your doctor and radiation therapist about deep inspiration breathing. That’s when you take a deep breath and hold it for 20 seconds while you get radiation. This moves your heart out of the way of the radiation beam to reduce its exposure. This same technique might also lower the amount of radiation exposure to your lungs.

Lie on your stomach. The prone position, or lying on your stomach, moves your breasts further away from your lungs. Lying in this position also helps the radiation spread more evenly throughout your breasts.

Skip radiation treatment. Depending on the size of your cancer and the likelihood of it growing, you might be able to skip radiation altogether. Talk to your treatment team about the best option based on your lung cancer risks and preferences.

Once you finish cancer treatment, you'll have regular follow-up visits with your doctor. During these visits, your doctor will see if the cancer you had has come back and screen you for new cancers. If you're at higher risk for lung cancer because of radiation therapy, smoking, or a family history, you may need to follow up with your doctor more often.

Between visits, watch for lung cancer symptoms like these and report them to your oncologist (a doctor who treats cancer):

  • A cough that doesn't go away
  • Shortness of breath
  • Coughing up blood
  • Chest pain
  • Hoarse voice
  • Weight loss you didn't plan

Treatment for lung cancer depends on the stage, but it can include:

  • Surgery to remove part or all of the lung
  • Radiation therapy
  • Chemotherapy
  • Targeted drugs
  • Immunotherapy

Fear of a future lung cancer doesn’t mean you shouldn’t treat the cancer you have now, but it is a reason to be more aware. For many people with cancer, the benefits of radiation far outweigh the risks. Ask your treatment team why they are recommending radiation therapy, how it will help you, and what side effects it might cause – both now and in the future.