Lung Cancer Symptoms, Diagnosis and Screening in Canada
Lung cancer is often called a silent disease.
In its early stages it usually causes no symptoms at all, and in Canada nearly half of all lung cancers are diagnosed at an advanced stage.
Knowing the symptoms, when to seek help, and whether you qualify for screening can make a real difference.
Key Takeaways
- In Canada, nearly half of all lung cancers are diagnosed at an advanced stage, because early disease usually causes no symptoms.
- A cough lasting more than three weeks, any blood when coughing, unexplained weight loss or new breathlessness should be discussed with a healthcare provider.
- Symptoms are easily mistaken for COPD, bronchitis or asthma, which is why people with COPD are at particular risk of delayed diagnosis.
- Diagnosis follows four steps: imaging, biopsy, molecular testing and staging.
- Low-dose CT screening can reduce lung cancer deaths by up to 20% in high-risk groups, and is available through provincial programs for adults aged 55 to 74 with a significant smoking history.
Table of Contents
Lung cancer is often called a silent disease. In its early stages, it usually causes no symptoms at all. In Canada, nearly half of all lung cancers are diagnosed at an advanced stage. Understanding the symptoms, knowing when to seek help, and knowing whether you qualify for screening can make a real difference.
Symptoms of Lung Cancer
Most Common Symptoms
- A cough that does not go away after three weeks, or one that worsens over time
- Coughing up blood, even a small amount
- Shortness of breath that is new or getting worse
- Chest pain, especially when breathing deeply or coughing
- Unexplained weight loss
- Persistent tiredness or loss of energy
- Loss of appetite
- Hoarseness or a change in voice
- Recurring chest infections
Less Common Symptoms
- Swelling of the face, neck, or arms
- Shoulder, arm, or hand pain from a tumour pressing on nerves near the top of the lung
- Difficulty swallowing
- Persistent wheezing
- Finger clubbing
When Cancer Has Spread
- Brain: headaches, confusion, vision changes, weakness or numbness
- Bones: aching pain in the back, hips, or ribs
- Liver: jaundice, abdominal discomfort
Why Symptoms Are Often Missed
A persistent cough is easily blamed on a cold, bronchitis, or seasonal changes. Shortness of breath may be attributed to aging or other known conditions, such as COPD or asthma.
People with COPD are at especially high risk of having lung cancer symptoms attributed to their existing lung disease. If you have COPD and notice any new or worsening symptom, it is worth discussing with your healthcare provider. Learn more about the connection between COPD and lung cancer.
When to See Your Healthcare Provider
Talk to your family doctor or nurse practitioner if you have:
- A cough lasting more than three weeks with no clear explanation
- Any blood when you cough
- Unexplained weight loss
- New or worsening breathlessness not explained by a known condition
How Lung Cancer Is Diagnosed
Step 1: Imaging
Chest X-ray or CT scan are usually the first tests ordered. A PET scan highlights areas where cancer may be active. A brain CT or MRI is often ordered in confirmed NSCLC to check for brain metastases, particularly if a driver mutation is identified (ALK, EGFR).
Step 2: Biopsy
A biopsy is essential to confirm the diagnosis. Methods include bronchoscopy, EBUS (Endobronchial Ultrasound), CT-guided needle biopsy, thoracentesis, and VATS (Video-Assisted Thoracoscopic Surgery).
Step 3: Molecular Testing
Once cancer is confirmed, the tissue is tested for specific genetic changes. These results determine which targeted therapies, if any, are appropriate.
Biomarkers routinely tested include: EGFR, ALK, ROS1, KRAS, BRAF, RET, MET, HER2, NTRK, and PD-L1. Comprehensive molecular testing is now standard of care for all patients with non-squamous NSCLC and should happen before treatment begins. Read more about molecular subtypes and biomarkers.
Step 4: Staging
NSCLC stages run from I (localized) to IV (spread to other organs). SCLC uses "limited" and "extensive" stage classification. Staging determines what treatment is possible.
Lung Cancer Screening in Canada
Low-dose CT scanning (LDCT) can detect lung cancer before symptoms appear and reduce lung cancer deaths by up to 20% in high-risk groups.
General eligibility in Canada:
- Aged 55 to 74
- Current smoker or quit within the past 15 years
- Significant smoking history (20 or more pack-years, varies by province)
Ontario Lung Screening Program (OLSP): Open to adults aged 55 to 74 with a significant smoking history. Referrals from family doctors or nurse practitioners.
British Columbia: Provincial program launched in 2022. Quebec and Alberta pilot programs are underway.
People with COPD and a significant smoking history are often among the best candidates for screening.
Free Video Education Series
RESPIPLUS has produced a 12-part video series on ALK-positive non-small cell lung cancer for healthcare professionals, covering diagnosis, treatment selection and the day-to-day management of targeted therapy.
Related Resources
References
Show references
- NHS. Lung Cancer. Symptoms. nhs.uk
- NHS. Lung Cancer. Overview. nhs.uk
- Mayo Clinic. Lung Cancer. Diagnosis and Treatment. mayoclinic.org
- Cleveland Clinic. Lung Cancer: Types, Stages, Symptoms, Diagnosis and Treatment. clevelandclinic.org
- Cancer Care Ontario. Ontario Lung Screening Program. cancercareontario.ca
- Canadian Association of Radiologists / CSTR. Practice Guideline on CT Screening for Lung Cancer 2025. car.ca
- Lim KP et al. Lung cancer screening primer. Can Fam Physician. 2021;67(11):817–820. cfp.ca
- Canadian Cancer Society. 5 Facts About Lung Cancer in Canada. 2023. cancer.ca
- Statistics Canada. Lung Cancer is the Leading Cause of Cancer Death in Canada. statcan.gc.ca
About this article
Written by Katrina Metz, RT, respiratory therapist and medical writer at RESPIPLUS. Medically reviewed by Dr. Claudia LeBlanc, MD, Senior Scientist at Princess Margaret Cancer Centre and a leading Canadian expert in ALK-positive NSCLC management.
About this project
This series was supported by Pfizer and developed independently by RESPIPLUS with the CARMA-BROS network. Scientific Committee: Dr. Geoffrey Liu (Princess Margaret), Maria Sedeno (RESPIPLUS), Emily Horvat (RESPIPLUS), Katrina Metz (RESPIPLUS), Christopher Deutschman (CARMA-BROS), Faisal Al Agha (CARMA-BROS). All materials are free and permanently hosted on chroniclungdiseases.com.
Published August 4, 2026. Last reviewed . For educational purposes only. Not a substitute for medical advice.