Bronchogenic carcinoma is the medical term for lung cancer, referring to tumors that originate in the lung tissue or the lining of the bronchi (the airways that carry air into the lungs). It is the leading cause of cancer death in the United States, with an estimated 226,650 new cases and 124,730 deaths expected in 2025. The term sounds more exotic than it is: if you’ve been reading about lung cancer, you’ve been reading about bronchogenic carcinoma.
Main Types of Bronchogenic Carcinoma
Bronchogenic carcinoma is divided into two broad categories based on how the cancer cells look under a microscope, and the distinction matters because it determines how the cancer behaves and how it’s treated.
Non-small cell lung cancer (NSCLC) accounts for 80% to 85% of all lung cancers. It has three main subtypes: adenocarcinoma (the most common, often found in non-smokers and in the outer parts of the lung), squamous cell carcinoma (more closely linked to smoking, typically found near the central airways), and large cell carcinoma (a less common, faster-growing form). These subtypes grow and spread at different rates, but they share enough biology that doctors often group them together when planning treatment.
Small cell lung cancer (SCLC) makes up 10% to 15% of cases. It is almost always tied to heavy smoking and is the more aggressive of the two. SCLC tends to grow quickly and spread early, often before it causes noticeable symptoms. A small remaining fraction of lung tumors, fewer than 5%, are carcinoid tumors, which grow much more slowly.
Risk Factors
Smoking is overwhelmingly the biggest risk factor. People who smoke cigarettes are 15 to 30 times more likely to develop lung cancer than people who never smoked. The risk climbs with the number of years you smoke and the number of cigarettes per day, and it drops steadily after quitting, though it never returns entirely to baseline.
Smoking isn’t the only cause. Indoor radon, a naturally occurring radioactive gas that seeps into homes from the ground, is the second leading cause of lung cancer in the United States and can cause the disease even in people who have never smoked. Workplace exposure to asbestos, arsenic, diesel exhaust, silica, and certain chromium compounds also raises risk, and the danger is compounded for workers who smoke. Living in areas with higher levels of air pollution adds a smaller but real increase in risk, and arsenic or radon in well water can contribute too.
Symptoms and When They Appear
Lung cancer typically produces no symptoms in its early stages. By the time people notice something wrong, the disease is often advanced. Symptoms that come from the tumor itself include a new cough that doesn’t go away, chest pain, coughing up blood, wheezing, and shortness of breath. Shortness of breath can result from the tumor blocking a major airway or from fluid collecting around the lungs or heart.
When the cancer spreads beyond the lungs, symptoms shift. Bone pain, headaches, unexplained weight loss, loss of appetite, and swelling in the face or neck are all signs that the disease has reached other parts of the body. None of these symptoms are unique to lung cancer, which is part of what makes early detection difficult.
Where Bronchogenic Carcinoma Spreads
The two types of lung cancer favor slightly different destinations when they metastasize. For NSCLC, the most common sites are the brain (29% of metastatic cases), bone (25%), adrenal glands (15%), and liver (13%). SCLC tends to spread to the liver first (33%), followed by the brain (30%), bone (27%), and adrenal glands (10%). The brain, bone, liver, and adrenal glands are the four organs that oncologists monitor most closely once lung cancer is diagnosed.
Genetic Drivers and Why They Matter
Some lung cancers are driven by specific genetic mutations that act like an “on switch” for tumor growth. The most important ones in NSCLC are mutations in the EGFR gene (common in adenocarcinoma in non-smokers), rearrangements of the ALK gene, and KRAS mutations (more common in adenocarcinoma in smokers). Squamous cell carcinoma is more often associated with mutations in a gene called TP53.
These mutations matter because they open the door to targeted therapy. If your tumor carries a specific driver mutation, there may be a drug designed to block exactly that growth signal. This is why virtually all newly diagnosed NSCLC patients now have their tumors tested for a panel of genetic changes before treatment begins.
How It’s Treated Today
Treatment depends on the type of lung cancer, the stage at diagnosis, and whether the tumor carries a targetable genetic mutation. The landscape has changed dramatically in the past decade.
For NSCLC with a known driver mutation, targeted drugs are now the cornerstone of treatment. Tumors with EGFR mutations are typically treated with drugs that block that specific growth signal, and these treatments have shown substantial survival benefits even in early-stage disease after surgery. ALK-positive tumors have their own class of targeted drugs, with multiple options available. Rarer mutations affecting genes like ROS1 and BRAF V600E also have approved targeted treatments. These therapies are generally taken as pills and tend to cause fewer severe side effects than traditional chemotherapy, though they come with their own set of side effects and the cancer can eventually develop resistance.
For NSCLC without a targetable mutation, immune checkpoint inhibitors have become a standard part of treatment. These drugs work by removing a “brake” that cancer cells use to hide from the immune system. They’re used alone or combined with chemotherapy, and they’ve extended survival for many patients with advanced disease. Immunotherapy is also increasingly used before or after surgery in earlier-stage cancers.
SCLC is typically treated with a combination of chemotherapy and immunotherapy for advanced disease, or chemotherapy with radiation for more limited disease. SCLC often responds well to initial treatment but tends to recur.
Surgery remains the best option for early-stage NSCLC that hasn’t spread. Radiation therapy plays a role for tumors that can’t be surgically removed and as a complement to other treatments.
Survival Rates and Prognosis
The overall death rate for lung and bronchus cancer is 31.5 per 100,000 people per year, making it the deadliest cancer in the country. Prognosis depends heavily on the stage at diagnosis. Lung cancer caught while still localized to the lung has a much better outlook than cancer that has already spread to distant organs. The challenge is that most cases are not caught early, since symptoms tend to appear late.
Survival rates have been improving, driven by better screening with low-dose CT scans for high-risk individuals, the explosion of targeted therapies, and the addition of immunotherapy to standard treatment. Patients whose tumors carry a treatable genetic mutation and who respond to targeted therapy often live significantly longer than historical averages would suggest. The gap between “lung cancer” as a single prognosis and the reality of many different diseases with very different outcomes continues to widen, making molecular testing at diagnosis one of the most important steps in modern lung cancer care.