
Lung Cancer Staging – What Patients Need to Know
By Dr. Kamran Ali, Thoracic Surgeon Introduction A diagnosis of lung cancer can change your whole world. There are so many questions, worries, and urgency to find clarity. An important first step after someone has been diagnosed with lung cancer is the step of staging. Understanding Lung Cancer Staging provides both doctor and patient with context for the disease – where it started, where it has spread, and the options for treatment that are the most relevant. In this article, we will describe in depth what Lung Cancer Staging means, how we stage the disease, and why Lung Cancer Staging is so significant in the treatment planning process. Regardless of whether you’re the newly diagnosed or caring for someone who is navigating this complex condition, this guide serves as a resource for understanding the process of lung cancer staging with an informed and confident perspective. What Is Lung Cancer Staging? Staging Lung Cancer is the determination of how much cancer is in the body and how far it has spread. Staging enables doctors to understand both the extent of the disease, which organs or lymph nodes are affected, and whether the disease has spread beyond the lungs. The purpose of staging the cancer is to answer the following three key questions: 1. Where is the primary tumor? 2. Has the cancer spread to nearby lymph nodes? 3. Has the cancer spread to distant places (metastatic)? If these are determined your doctor can derive the most effective plan for treatment, whether surgery, chemotherapy, radiation, immunotherapy, or some combination of all these approaches. Why Is Lung Cancer Staging So Important? To patients, Lung Cancer Staging is not a medical concept — it establishes a roadmap for any subsequent decision. It determines: • Treatment Options: Whether surgical options are feasible or if non-surgical treatments are deemed more effective. • Prognosis: It gives you an idea of the expected outcome and survival statistics. • Clinical Trials: Many clinical studies or new therapies have patients enrolled in a certain cancer stage. • Communication: It allows doctors across many health care systems from around the world to discuss each treatment, using the same terms, and for hospitals to compare those treatment outcomes. Types of Lung Cancer Before we cover further details about Lung Cancer Staging, it’s important to note that lung cancer is not a single disease. Lung cancer is primarily divided into two main categories: 1. Non-Small Cell Lung Cancer – this is the most common, approximately 85% of lung cancers fall into this category, some of the subtypes include, 2. Small Cell Lung Cancer – this is more aggressive and spreads quicker than non-small cell lung cancer and it accounts for approximately 10% to 15% of lung cancers. Both types have different staging systems, but the principles are largely the same. How Is Lung Cancer Staging Done? Staging consists of a series of tests, scans, and occasionally minor procedures. It may seem complicated, but every step eventually leads to information that helps develop an accurate picture. 1. Tests with Imaging These are used to find the tumor and determine if it has spread: • CT (Computed Tomography) Scan: Provides detailed cross-sectional images of the chest and abdomen. • PET (Positron Emission Tomography) Scan: Shows areas of active cancer cell throughout the body. • MRI (Magnetic Resonance Imaging): Used frequently to determine if there is brain metastasis. • Bone Scan: Shows if cancer has gone to the bones. 2. Biopsy and Pathology Looking at a sample of the tumor establishes that the tumor is cancer and sometimes can provide additional molecular information that helps determine treatment. Some methods to obtain tissue are: • Bronchoscopy: A camera-tipped tube goes through the airway to visualize and biopsy tissue from the area of suspicion. • CT-guided Needle Biopsy: Uses imaging to obtain a sample from a lung mass. • Mediastinoscopy: Permits biopsy of lymph nodes located in the chest. 3. Surgical Assessment Sometimes surgery alone serves the purposes of determining the extent of disease spread, especially the lymph nodes. 4. Molecular and Genetic Testing Newer testing seeks to identify specific mutations (most commonly EGFR, ALK, KRAS mutations) that can be targeted with precision therapies — a major component of planning lung cancer treatment in 2022. The TNM System of Lung Cancer Staging The stage of lung cancer is most commonly estimated by the TNM classification established by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC). The letters represent different aspects of the disease: ‘T’ represents the size and location of the primary tumor, ‘N’ indicates whether the cancer has spread to nearby lymph nodes, and ‘M’ indicates whether the cancer has spread to distant organs. Each of these components has its own numerical grading, and the overall stage is determined by the combination of the components. T – Tumor (Primary Site) Category Description T1 Tumor ≤3 cm, confined to one lobe of the lung T2 Tumor >3 cm but ≤5 cm or involves nearby structures like the main bronchus T3 Tumor >5 cm but ≤7 cm or invades nearby structures such as the chest wall T4 Tumor >7 cm or invades major organs (heart, trachea, esophagus) or has multiple nodules in the same lobe N – Nodes (Lymph Node Involvement) Category Description N0 No lymph node involvement N1 Spread to nodes within the lung or near the bronchi N2 Spread to mediastinal or subcarinal lymph nodes (mid-chest) N3 Spread to lymph nodes on the opposite side of the chest or neck M – Metastasis (Spread to Other Organs) Category Description M0 No distant metastasis M1a Cancer in the opposite lung or in the fluid around the lung/heart M1b Single distant metastasis (one organ site) M1c Multiple distant metastases (multiple organs) Lung Cancer Staging Chart (Stage I to IV) Once the TNM classifications are made, they are placed into greater overall stages (Stage 0 – Stage IV). Stage 0 (Carcinoma in situ) • The cancer is located only in the top








