Lung cancer doesn’t always shout when it arrives. In fact, it can creep in quietly—no warning, no pain, no obvious symptoms—until it’s well advanced. So how do doctors catch it in time? That’s where diagnosis comes in. But what does that process look like? What tests are involved? And how do you even know when it’s time to get checked?
Let’s break it all down.
Why Early Diagnosis of Lung Cancer Matters
Let’s be honest—most people don’t rush to the doctor for a mild cough. But with lung cancer, waiting can cost lives. According to the American Lung Association, the five-year survival rate for early-stage lung cancer is around 60%. Once it spreads? That rate drops dramatically—sometimes below 10%.
Why? Because early-stage lung cancer often has no symptoms. By the time someone starts coughing up blood or feels chest pain, the disease might already be on the move.
That’s why early detection is everything.
It gives you options. It opens the door to curative treatments. And it gives doctors a fighting chance to stop the disease before it spreads.
When Should You Get Tested?
That’s the million-dollar question.
Not everyone needs to get screened for lung cancer. But certain people should absolutely consider it:
- Adults aged 50 to 80 who have a 20 pack-year smoking history (meaning a pack a day for 20 years—or two packs a day for 10 years), and
- Are currently smoking or have quit within the past 15 years
This group is considered high-risk. For them, screening can actually save lives.
What about symptoms? If you experience any of the following, it’s time to see a doctor:
- Persistent cough that won’t go away
- Chest pain
- Hoarseness
- Shortness of breath
- Coughing up blood
- Unexplained weight loss
Still unsure? Ask yourself: Has something changed in my body that I can’t explain? That’s reason enough to get checked.
Chest X-Ray: The Starting Point
This is usually where the journey begins. It’s quick, painless, and widely available.
A chest X-ray can spot larger tumours or lung abnormalities. But here’s the catch—it can miss smaller or early-stage cancers. That’s why a clear X-ray doesn’t always mean you’re in the clear.
Think of it as a first glance, not the whole picture.
CT Scan: A Closer, More Detailed Look
If an X-ray raises suspicion—or if you’re in the high-risk group—your doctor may order a CT scan (computed tomography).
What’s so special about it?
- It takes multiple images of your chest from different angles
- Then, it stitches them together to form detailed cross-sections
This allows doctors to see much smaller tumours that an X-ray might miss. It’s also the go-to test for lung cancer screening, especially low-dose CT (LDCT) for high-risk individuals.
Is it safe? Generally, yes. While CT scans use more radiation than X-rays, LDCT minimizes exposure, making it a safer tool for routine screening.
PET Scan: Tracking Active Cancer Cells
Imagine if doctors could see not just the tumour, but also how active it is. That’s what a PET scan (positron emission tomography) does.
It uses a small amount of radioactive sugar. Cancer cells love sugar—they gobble it up. The scanner then highlights these sugar-hungry cells, making cancer stand out.
PET scans are especially useful for:
- Checking if the cancer has spread
- Distinguishing between scar tissue and active tumours
It’s not typically a first test, but it plays a crucial role in staging.
Sputum Cytology: Can Your Phlegm Reveal Cancer?
Yes, really—your phlegm can tell a story.
Sputum cytology involves coughing up mucus from the lungs and examining it under a microscope to look for cancer cells.
It’s:
- Non-invasive
- Inexpensive
But it’s not perfect. It works best for central lung cancers (those near the airways) but often misses peripheral tumours.
Still, in the right context, it’s a useful clue.
Bronchoscopy: Looking Inside Your Lungs
When doctors need to see what’s going on inside your airways, they use a bronchoscope—a thin tube with a camera that goes into your lungs via your mouth or nose.
Sounds uncomfortable? Don’t worry. You’ll usually be sedated.
During a bronchoscopy, doctors can:
- Visually inspect the airways
- Collect tissue samples (biopsy)
- Wash parts of the lung to collect cells (lavage)
This is especially helpful for centrally located tumours.
Biopsy: Getting a Tissue Sample
This is the gold standard. You can’t confirm lung cancer without a biopsy.
There are different ways to get a sample:
- Needle biopsy: Often guided by a CT scan
- Bronchoscopic biopsy: Taken during bronchoscopy
- Surgical biopsy: For hard-to-reach areas
What happens to the tissue?
It gets sent to a lab, where pathologists look under a microscope and test for cancer type, aggressiveness, and even specific genetic mutations (more on that below).
Risks? There’s a small chance of bleeding or a collapsed lung, but it’s generally safe and done under local anesthesia.
Blood Tests and Biomarkers: What Do They Tell Us?
Can a simple blood test detect lung cancer?
Not quite yet—but we’re getting there.
Currently, blood tests can’t diagnose lung cancer on their own. But they do help by:
- Checking overall health (e.g., liver and kidney function)
- Looking for markers of inflammation
- Monitoring treatment response
Emerging tests like liquid biopsy are making headlines. These detect fragments of tumour DNA floating in the blood. They’re not yet routine for diagnosis but may soon become part of the standard workup.
Genetic and Molecular Testing
Once lung cancer is confirmed, the next question is: What kind is it? That’s where molecular testing comes in.
Doctors test the tumour for specific gene mutations like:
- EGFR
- ALK
- ROS1
Why does this matter?
Because some drugs only work if your tumour has a specific mutation. These are targeted therapies, and they’ve revolutionized treatment for many patients.
No two cancers are alike. Molecular testing helps doctors personalise your care.
Staging Tests: Has It Spread?
Once cancer is found, the next step is figuring out how far it’s spread. This is called staging, and it guides treatment.
Staging tests may include:
- PET scan (we discussed earlier)
- MRI of the brain (to check for spread to the brain)
- Bone scans (to look for bone metastases)
- Ultrasound or CT of the abdomen (for liver, adrenal glands)
The stage ranges from Stage I (early) to Stage IV (advanced).
Knowing the stage is key to choosing between surgery, chemotherapy, immunotherapy—or a mix.
What to Expect During the Diagnostic Journey
Let’s face it—getting tested for lung cancer can be overwhelming. There’s fear, waiting, and a ton of medical jargon.
But knowing what to expect can help ease the stress.
Here’s a rough path:
- Initial visit – Symptoms or screening prompts a doctor’s evaluation
- Imaging tests – Chest X-ray → CT scan → PET scan
- Biopsy – Tissue sample confirms cancer
- Molecular testing – Identifies mutations
- Staging – Determines treatment path
Each step brings you closer to answers. Ask questions. Take notes. Bring someone with you for support.
Conclusion: Don’t Wait for Symptoms to Speak Loudly
Lung cancer doesn’t always come with sirens and flashing lights. Sometimes, it whispers—or stays silent altogether. But if you’re at risk or notice unusual symptoms, speak up. The earlier it’s caught, the better the outcomes.
Diagnosis may involve several steps, but each test has its place. Together, they build a complete picture—helping you and your doctors make the best possible decisions.
References
- “Lung Cancer Screening Guidelines,” American Lung Association, 2023. https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/screening
- “Low-Dose CT Screening for Lung Cancer,” National Cancer Institute, 2022. https://www.cancer.gov/types/lung/research/ct-screening
- “How Lung Cancer Is Diagnosed,” Cancer Research UK, 2023. https://www.cancerresearchuk.org/about-cancer/lung-cancer/getting-diagnosed/tests
- “Understanding PET Scans,” RadiologyInfo.org, 2022. https://www.radiologyinfo.org/en/info/pet
- “Molecular Testing for Lung Cancer,” American Society of Clinical Oncology (ASCO), 2023. https://www.cancer.net/navigating-cancer-care/diagnosing-cancer/tests-and-procedures/molecular-testing