Lung cancer can present with respiratory or systemic symptoms, but may be silent early on. Smoking is the main risk factor, though radon, pollution, occupational exposures, and genetics also contribute. Diagnosis uses imaging and biopsy; molecular testing guides targeted and immunotherapy options. High-risk individuals may benefit from annual low-dose CT screening. Prompt medical evaluation improves treatment choices and outcomes.

Overview

Lung cancer symptoms can be subtle early on. Many people attribute cough, breathlessness, or fatigue to smoking, infections, or aging. Still, persistent or new respiratory symptoms deserve evaluation because early detection improves treatment options and outcomes.

Common signs and symptoms

Respiratory symptoms

  • A new or changing cough that lasts more than a few weeks
  • Shortness of breath or wheezing
  • Coughing up blood (even small amounts)
  • Chest pain that is persistent or worsens with breathing or coughing

Systemic symptoms

  • Unexpected weight loss or poor appetite
  • Unexplained fatigue or weakness
  • Recurrent chest infections
Some early-stage lung cancers cause no symptoms and are found incidentally on imaging.

Types and risk factors

Lung cancer is broadly divided into two categories: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC includes common subtypes such as adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Smoking remains the leading risk factor, but other contributors include radon exposure, air pollution, workplace exposures (asbestos, diesel exhaust), prior radiation to the chest, and family history. Tumors may also harbor genetic changes (EGFR, ALK, ROS1, KRAS and others) that guide treatment.

Diagnosis and screening

Initial tests often include a chest X-ray and a contrast CT scan. For tissue diagnosis, doctors use bronchoscopy, CT-guided needle biopsy, or surgical biopsy. Staging commonly uses PET-CT and brain MRI when spread is suspected.

For people at high risk, low-dose CT (LDCT) screening can detect cancers earlier. Current guidelines recommend annual LDCT screening for selected high-risk adults; eligibility criteria vary by age and smoking history ( - verify the most recent USPSTF or society guideline for the exact thresholds).

Molecular testing on tumor samples is routine for many NSCLC cases to identify targetable mutations. PD-L1 testing helps determine suitability for immunotherapy.

Treatment overview

Treatment depends on stage and tumor biology. Options include:
  • Surgery for early-stage disease
  • Radiation therapy for localized disease or symptom control
  • Chemotherapy, historically a backbone for many cases
  • Targeted therapies for tumors with driver mutations (EGFR, ALK, ROS1, BRAF, NTRK, KRAS G12C, etc.)
  • Immunotherapy (PD-1/PD-L1 inhibitors) alone or in combination with chemotherapy
Side effects vary by treatment: fatigue, nausea, hair changes, immune-related effects, and blood count changes are common. Supportive medications and symptom management improve tolerance.

When to see a doctor

See a clinician if you have a persistent cough, unexplained weight loss, blood in sputum, or worsening breathlessness. If you meet high-risk criteria for lung cancer screening or have significant exposure history (long-term smoking, radon, occupational hazards), discuss LDCT screening with your provider.

Early evaluation, accurate diagnosis, and molecular testing expand treatment choices and can improve outcomes.

  1. Confirm current USPSTF (or relevant society) lung cancer screening age and pack-year eligibility criteria for annual low-dose CT.
  2. Verify any recent changes (2023-2025) to screening recommendations or major guideline updates relevant to high-risk populations.

FAQs about Signs Of Lung Cancer

What are the earliest signs of lung cancer?
Early signs can be subtle or absent. Common early symptoms include a new or changing cough, mild shortness of breath, or recurrent chest infections. Persistent symptoms should prompt evaluation.
Who should get screened for lung cancer?
People at high risk - generally those with a significant smoking history - may benefit from annual low-dose CT screening. Exact eligibility criteria depend on current guideline thresholds (). Talk with your clinician about whether screening applies to you.
How is lung cancer diagnosed?
Diagnosis typically starts with imaging (chest X-ray and CT). A tissue diagnosis is obtained with bronchoscopy, needle biopsy, or surgery. PET-CT and brain MRI help stage the disease, and molecular testing on the tumor guides targeted therapy options.
Can non-smokers get lung cancer?
Yes. While smoking is the leading risk factor, non-smokers can develop lung cancer due to radon, air pollution, occupational exposures, prior radiation, or underlying genetic changes.
What treatments are available now?
Treatment depends on stage and tumor biology and may include surgery, radiation, chemotherapy, targeted drugs for tumors with specific mutations, and immunotherapy. Many patients receive combination approaches tailored to their cancer.