What Is Bronchogenic Carcinoma?

Bronchogenic carcinoma was once used to describe a specific type of cancer that arises in the bronchi (the large airways of the lungs) and bronchioles (the small branches into which the airways divide). Today, it is considered another name for lung cancer in general.

Bronchogenic carcinoma is the most common cancer worldwide and is the leading cancer-related cause of death in both men and women in the U.S.

While the survival rate for lung cancer continues to be relatively low compared to other cancers, treatment options are improving. Those diagnosed with bronchogenic carcinoma today are living longer than those diagnosed in previous generations.

Read on for a review of the different types of bronchogenic carcinoma, their symptoms and what causes them, and how healthcare providers identify and treat cases.

Types of Bronchogenic Carcinoma

There are three types of bronchogenic carcinoma:

• Small cell lung cancer (SCLC): Approximately 10% to 15% of people with lung cancer are diagnosed with SCLC. This type of cancer is named for the size of the cells as viewed under a microscope. There are two subtypes of SCLC: small cell carcinoma (sometimes called oat cell cancer) and combined small cell carcinoma.
• Non-small cell lung cancer (NSCLC): NSCLC accounts for most bronchogenic carcinomas (around 80% to 85%). NSCLC is further subdivided into lung adenocarcinoma, squamous cell carcinoma of the lungs, and large cell lung cancer.
• Carcinoid tumors: This rarer type of bronchogenic carcinoma accounts for less than 5% of lung cancer cases.

Historically, squamous cell NSCLC was the most common type of bronchogenic carcinoma. That trend has been changing as rates of squamous cell carcinoma have fallen as smoking habits have changed.

Adenocarcinoma is now the most common form of bronchogenic carcinoma. Approximately 40% of NSCLC patients are diagnosed with adenocarcinoma, which usually begins with tumors in the outer areas of the lungs. It often isn't detected until the cancer has grown large enough to affect breathing in the central region of the lung.

Symptoms of Bronchogenic Carcinoma

People with adenocarcinoma often have no symptoms in the early stages of the disease. With other types of bronchogenic carcinoma, however, there may be some general signs of cancer such as:

• Unintentional weight loss
• Fatigue
• Shortness of breath, especially with exercise

As tumors begin to interfere with the function of the lungs and cause problems in the large airways, symptoms specifically related to breathing usually occur.

Other body systems may also be affected by tumor growth or tumor secretion of substances that interfere with normal functions.

Among the most common symptoms of bronchogenic carcinoma are:

• Persistent cough
• Wheezing
• Coughing up blood
• Hoarseness
• Pain in the chest or back
• Repeated infections such as pneumonia or bronchitis
• Clubbing (rounding) of the fingers

Causes

The leading risk factor for bronchogenic carcinoma is smoking, which is linked to 80% to 90% of lung cancer deaths each year.

Other leading risk factors for developing bronchogenic carcinoma include:

• Secondhand smoke: An estimated 7,330 lung cancer deaths each year are related to smoke exhaled by smokers and emitted from the lit end of a cigarette, pipe, or cigar, or from tobacco burning in a hookah.
• Radon exposure: Radon is the second most common cause of NSCLC and the most common cause among never-smokers. It is responsible for roughly 21,000 lung cancer deaths each year.
• Occupational exposure to carcinogens: Direct, on-the-job exposure to arsenic, beryllium, vinyl chloride, polycyclic aromatic hydrocarbons (PAHs), silica, wood dust, and asbestos is known to raise your risk of bronchogenic carcinoma. Asbestos is also highly associated with mesothelioma, a rare type of cancer that affects the lungs.
• Ionizing radiation: This type of radiation administered to the chest, usually as a treatment for another disease such as breast cancer, can significantly increase your risk of bronchogenic carcinoma.

Diagnosis

The diagnosis of bronchogenic carcinoma may be made in several ways including through the use of imaging, tissue sample evaluations, and blood tests.

As part of making a diagnosis, a cancer specialist known as an oncologist will stage bronchogenic carcinoma to assist with making your treatment plan.

• SCLC is usually divided into two stages: limited and extensive.
• NSCLC is divided into four stages with subtypes and designations for each.

Imaging

Sometimes a healthcare provider finds an abnormality on a chest X-ray prompting further evaluation with chest computed tomography (CT) or other imaging methods.

A positron emission tomography (PET) scan may also be ordered. This is the most sensitive test among the three and may be the best way to accurately stage the disease.

Biopsy

A lung biopsy is also usually required to make an accurate determination about the stage of bronchogenic carcinoma.

It is also used for genetic testing, in which healthcare providers identify genetic mutations that might be present in your lung cancer cells. If they identify certain known mutations, targeted therapies can be used to prevent the cancer cells from growing or causing further problems.

A biopsy may be done in a few different ways:

• Bronchoscopy: A flexible tube equipped with a camera is inserted into the mouth and advanced to the location of the tumor for removal of a small tissue sample.
• Fine needle aspiration (FNA): A special long needle is inserted into the chest to remove a small number of tumor cells.
• Thoracoscopic biopsy: In this minimally invasive procedure, a tissue sample is taken through small incisions.
• Open lung biopsy: The chest is opened and a tissue sample removed surgically.
• Thoracentesis: Chest fluid samples are taken using a special needle.

Blood Tests

Healthcare providers will also order a complete blood count and blood chemistries to get a comprehensive picture of your cancer and overall health. If tumors are associated with paraneoplastic syndromes, your tests may include measures of sodium and calcium levels in the blood.

Increasingly, healthcare providers are using liquid biopsy (rapid plasma genotyping) to help diagnose and direct treatment of cancer. This is a blood test that can detect cancer cells circulating in the blood, as well as genetic mutations in those cells.

Using those results, healthcare providers determine if your cancer might respond to treatment with targeted medications.

Who Should Be Screened?

Many bronchogenic carcinoma cases are caught because testing is done to investigate the cause of worrisome symptoms. Others are detected because of lung cancer screening tests.

Screening tests are done to look for signs of disease in patients who are considered to be at advanced risk. In the case of bronchogenic carcinoma, screening may decrease the mortality rate by at least 20%.

Low-dose CT screening for bronchogenic carcinoma is advised for people who:

• Are between 50 and 80 years old
• Have a 20 pack-year history of smoking
• Currently smoke or have quit within the last 15 years
• Are healthy enough overall to tolerate treatment if diagnosed with lung cancer

If you meet these criteria or have other risk factors for lung cancer, talk to your healthcare provider about screening. They may also recommend continuing annual screening even after it's been 15 years since quitting smoking.

Unfortunately, only a minority of people who are eligible do. As a result, lung cancers that could have been caught and more effectively treated early on aren't diagnosed until they advance to later, incurable stages.

Treatment

The treatments your healthcare provider recommends will depend on several factors, including the type and stage of lung cancer you are diagnosed with.

It is important to learn about your diagnosis because being actively involved in your lung cancer care may help you have a better outcome.

Possible treatments may include:

• Surgery: Surgery may be an option for early-stage NSCLC. However, some tumors can't be removed this way due either their location or the extent of the spread (metastasis).
• Chemotherapy: Chemotherapy drugs kill cancer cells and may be used alone or after surgery to ensure all the cancer cells are destroyed.
• Radiation therapy: Radiation therapy may be used to target local tumors or to support chemotherapy or surgery.
• Targeted therapies: Targeted therapy drugs can stop cancer cells with specific genetic mutations from growing.
• Immunotherapy: These drugs help your own immune system recognize and attack cancer cells.

New cancer treatments are continually being tested. You can enroll in clinical trials if you want to try out experimental treatments, which may offer new hope.

Prognosis

The overall five-year survival rate for bronchogenic carcinoma is about 18.6%. Prognosis varies based on the type and stage of lung cancer, with survival rates being much better when the disease is diagnosed in the earlier stages.

Though these statistics are sobering, advances in the treatment of lung cancer are improving survival—even for people with metastatic (stage 4) disease.

The survival rate for lung cancer has increased steadily over the past 40 years from 12.4% in the mid-1970s to 20.5% by 2016.

Finding the right treatment may take some additional testing and a new perspective. Getting a second opinion, preferably at a National Cancer Institute-designated cancer center, can be of tremendous importance.

A Word From Verywell

While the overall incidence of bronchogenic carcinoma has been decreasing in recent years, it has increased significantly for young women who have never smoked.

This shows that there is still much to learn about the risks of lung cancer and the ways doctors should approach the disease.