When you hear your doctor mention “radiation pneumonia” during chest radiation therapy, it can be mysterious and scary. Is this “pneumonia” serious? How do you deal with it if it happens? Next, let’s talk about it.
What is “pneumonia”?
What is “radiation pneumonia”?
What is radiation pneumonia?
With any form of treatment, there can be adverse effects, but they can be mild or severe. Radiation therapy is no exception.
Radiation pneumonitis, also called acute radiation lung injury, is one of the common adverse effects of chest radiotherapy. It is an injury to the lung tissue that occurs after a certain dose of radiation exposure and generally occurs within 6 months of the start of radiotherapy, called radiation pneumonitis, and after 6 months, called radiation pulmonary fibrosis. The former is likely to recover with active and effective treatment, while the latter is often irreversible. However, in practice, the two clinically observed stages are a continuous process with no clear boundary between them.
Why does radiation pneumonia occur?
The current professional opinion is that after a certain dose of irradiation of lung tissue, damage occurs to the alveolar epithelium, which in turn causes the release of various cytokines and induces a variety of cellular inflammatory responses to repair the damage, which also gradually leaves a fibrotic scar during the repair process.
Which patients are more susceptible?
- Those who are older (mostly 60-70 years old)
- with concomitant lung disease (chronic obstructive pulmonary disease, interstitial lung disease, lung infection, etc.)
- Large extent of lung lesions and thus higher dose of irradiation to normal lung tissue
- Lower lung lobe lesions are more likely to occur compared with other lung lobe lesions
- Concurrent or recent use of gemcitabine, bleomycin, or other chemotherapeutic agents that predispose to interstitial pneumonia, pulmonary edema, and pulmonary fibrosis
If you have any of these high-risk factors, there is no need to be overly anxious or worried. In addition to the above factors that may be associated with the occurrence of radiation lung injury, the sensitivity to radiation varies widely from person to person. Your radiologist will make sure to weigh and consider your situation when planning your treatment and make an individualized judgment about whether you can tolerate radiation therapy to treat the tumor while protecting as much normal lung tissue as possible.
What are the signs?
The majority of radiation lung injuries occur.
Radiation lung injury occurs mostly within 6 months of the start of radiotherapy. the manifestations of upper CT pneumonitis are mostly confined to the irradiated area, with a few imaging changes outside the irradiated area.
You may have a cough, shortness of breath, or fever that worsens after radiation therapy, or reappears after being reduced or resolved by radiation therapy.
It is important to note that not all pneumonia that occurs after radiation therapy is associated with radiation therapy. This requires a comprehensive assessment and judgment by the radiotherapist based on the extent of exposure, the direction of field incidence, the dose and volume of lung irradiation, and the patient’s underlying lung condition, as well as pathogenic testing to rule out lung infection (bacterial, fungal, or viral).
In addition to infection (or concomitant infection), care must be taken to differentiate from tumor progression, cancerous lymphangitis, acute exacerbation of preexisting chronic obstructive pulmonary disease, and pulmonary embolism.
How to respond?
After a diagnosis of radiation lung injury, whether and how treatment is needed is treated in the following ways:
- If there is only a mild manifestation of fibrous scarring on CT but no symptoms or only a mild dry cough, no medication is needed;
- If cough and shortness of breath are present, but the symptoms are mild and there is no fever, only symptomatic treatment such as oral cough syrup or phlegmolytic or asthma medication is needed, and antibiotics can be considered to prevent infection;
- If the cough and shortness of breath are severe and interfere with daily life, or if they are accompanied by high fever or CT showing significant exudation, and occur during radiotherapy, radiotherapy needs to be stopped immediately, and intravenous anti-inflammatory therapy along with glucocorticoids, oxygen, and ventilator-assisted ventilation is required.
It is important to note that once hormones are administered, they must be administered in full doses for the full duration of the treatment, and then tapered after symptoms are controlled and imaging is significantly better. You should not reduce the dose too quickly or stop the medication at will to avoid rebound.
Radiation pneumonia, it’s not that bad
You may think that radiation lung injury after radiation therapy is more serious than the complications of open-heart surgery. Let’s just use the data and compare the incidence of the two.
The incidence of radiation lung injury in patients undergoing chest radiotherapy ranges from 7% to 37%, both asymptomatic and symptomatic. Not all changes in radiological lung injury that show up on CT will be symptomatic, and only 30% to 35% of these will be symptomatic and require treatment.
With control of the volume and dose of normal lung irradiation, the incidence of severe symptomatic radiation lung injury is only about 10% to 15%, and the lethality rate is only 0.6% to 2% of all patients undergoing chest radiotherapy.
The National Cancer Institute (NCI) database shows that the complication rate after open-heart surgery is 54.4%, including 8.5% for pneumonia, 15.6% for atelectasis, 4.5% for the need for a ventilator, and 1.4% for sepsis. The mortality rate was 2% within 30 days and 3.59% within 90 days after early lung cancer surgery, and increased with age and extent of surgery.
From these comparisons, radiological lung injury is not more frightening than surgical complications, and the incidence is not as high as one might think, but the “fear” is simply a lack of awareness.
Summary: Your doctor will consider your health before treatment to develop the most appropriate radiotherapy plan. In the event of radiation pneumonitis, please also cooperate and follow your doctor’s instructions to respond proactively and adjust your medication and dose according to changes in your condition to ensure that you can get through this period safely. Never give up an important and effective local treatment because of fear or misunderstanding.
Co-reviewed by: Guangdong Provincial People’s Hospital Guangdong Provincial Lung Cancer Institute Dr. Pan Yao, Chief Physician Dr. Chen Zhiyong Dr. Zhang Jiatao