What is Pulmonary Function Testing and How It is Used in Lung Cancer Diagnosis
What is Lung Cancer?
Lung cancer is currently the leading cause of cancer-related death in the United States. It is responsible for the highest number of “neoplastic” deaths among men and women. An estimated mortality rate of Americans suffering from lung cancer in 2018 is 154,050, which is approximately 25% of all cancer deaths. Smoking remains the major risk factor that causes lung cancer. It contributes to 80 – 90% of lung cancer deaths in women and men respectively. Signs and symptoms may vary depending on the type of tumor and state of metastases.
What is Pulmonary Function Test?
Pulmonary Function Test (PFT) includes a series of non-invasive tests that monitor breathing, and how efficiently the lungs are working. With these tests, the lung volume, diffusion capacity, and airflow are measured. It also assesses the ability of the lungs to facilitate oxygen flow from the air into the bloodstream, and carbon dioxide from the bloodstream into the lungs.
Your doctor may suggest PFTs
- If you have any symptoms of lung problems
- To evaluate the course of various chronic lung diseases such as asthma or chronic obstructive pulmonary disease (COPD)
- To determine whether or not your lungs are performing in an optimal condition before you have surgery
- To diagnose small cell and non-small cell lung cancer in patients
Pulmonary Function Test in Lung Cancer Diagnosis
Recent studies show an average of 50-80% of patients diagnosed with lung cancer had pre-existing COPD, or chronic obstructive pulmonary disease. Having a lung problem in any stage of life is expected to increase the risk of lung cancer, and this is independent of smoking exposure, sex, and ethnicity. There exists a close relationship between obstructive pulmonary disease and lung cancer.
The COPD-lung cancer association may be based on the cause of pathogenetic pathways overlapping with each other, where extreme inflammation and lung remodeling leads to COPD, and subsequent epithelial-mesenchymal transition causes malignancy. A pulmonary function test helps determine the lung condition, which can eventually aid in lung cancer diagnosis.
PFTs are performed on a routine basis on the patients diagnosed with lung cancer. The results from lung function tests may help the physician determine the right treatment plan – surgery, radiation, and/or chemotherapy. For patients showing signs & symptoms of lung cancer, pulmonary function tests can be useful in early diagnosis and treatment. Prior to planned surgical treatment of lung cancer, it is important to evaluate the patient’s respiratory system functioning. Certain measurements achieved through lung function test can also be of use in such case.
What Does Pulmonary Function Test Measure in Lung Cancer Diagnosis & Resection?
PFTs are conducted both for lung cancer diagnosis and qualifying diagnosed for lung parenchyma resection. As per the current guidelines of ESTS and ERS, two kinds of PFTs are recommended – Spirometry, which measures FEV1 or Forced Expiratory Volume in 1 second, and evaluation of DLcoor the carbon monoxide diffusion capacity of the lungs.
If either of the parameters are less than 80%, your physician may suggest an exercise test with VO2 Max measurement, i.e. oxygen consumption during maximal exercise. If the measurement is < 35 % p.v. or < 10 ml/kg/min, lung cancer surgery is associated with considerable risk. The exercise test may also be replaced with other PFTs such as stair climbing test and the shuttle walk.
Exercise tests are commonly used in lung cancer diagnostics due to high prognostic value in terms of FEV1 and DLCO measurements. High levels of muscle engagement in exercise tests burden the respiratory system significantly, helping in monitoring lung performance and identifying abnormal measurements if any.
Doctors may also suggest certain post-operative pulmonary function tests to evaluate lung functioning after lung resection.
Types of Pulmonary Function Test Used in Lung Cancer
According to the latest guidelines, your doctor may suggest Spirometry and Diffusion Capacity Test for lung cancer diagnosis and preoperative or postoperative evaluation.
- Spirometry: Spirometry is a type of pulmonary function test that assesses the amount of air you breathe in and out. For the test, you have to sit in front of a machine and wear a sung-fit mouthpiece. A nose clip will be attached to prevent you from breathing air out through the nose. Breathe normally. The respiratory technologist will ask you to breathe in and out as quickly or as deeply you can for a few seconds. If nasal airways are closed, you may have to breathe in a medication, and then breathe into the machine.
- Diffusion Capacity Test: This kind of PFT is useful in assessing how optimally the alveoli (small air sacks inside your lungs) work. For this test, you have to breathe in certain gases such as oxygen, carbon dioxide, or helium. You may also be asked to breathe in ‘tracer gases in one breathe. The machine will automatically identify when you breathe out the gas. The test helps evaluate whether your lungs can optimally move oxygen and carbon dioxide to and from the bloodstream.
What are the Risks of Pulmonary Function Tests?
Pulmonary function tests are usually safe for most patients. However, in certain cases, it can cause problems. A PFT can have risks if:
- You have a heart disease
- You have recently had a chest surgery, heart attack, or eye surgery
- You have recently undergone abdominal surgery
- You are suffering from acute respiratory infection
Since you may have to breathe in and out fast during a PFT, you may feel dizzy and lightheaded. Report it to your doctor immediately. In rare cases, pulmonary function tests for lung cancer may lead to the risk of collapsed lungs.
How to Prepare for Pulmonary Function Test for Lung Cancer Diagnosis
When you visit EPIC Primary Care for Pulmonary Function Test, an experienced physician will elaborately explain the procedures, evaluation parameters, and risk factors. If you are under any kind of medication, please inform the same to your doctor. Here is how to prepare for a PFT:
- Stop smoking & certain medications several hours before the test as suggested by your doctor
- The technician will measure your weight and height to calculate the results effectively
- Wear loose clothes; remove all jewelry
- Avoid heavy meals and empty your bladder before the test
- Sit in front of the machine and wear the mouthpiece for a snug fit. A clip will be attached to your nose to keep you from breathing out the air
- Breathe in and out, deeply or quickly, as instructed by the technician
- The technician will closely monitor for signs of breathing trouble, dizziness, etc.
If you are suspected of lung cancer and your physician has recommended pulmonary function tests, EPIC Primary Care is the right choice for you. We are equipped with state-of-the-art technology and vast knowledge to deliver unmatched healthcare services to our patients.
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