Today, “bronchoalveolar carcinoma” is an obsolete term.
In
The purpose of the reclassification was to better differentiate between cancers that tend to be aggressive versus nonaggressive.
What was formerly known as bronchoalveolar carcinoma (BAC) has now been separated into four categories:
- adenocarcinoma in situ
- minimally invasive adenocarcinoma
- lepidic predominant adenocarcinoma
- invasive mucinous adenocarcinoma
Adenocarcinoma is a cancer that forms in mucous glands. Along with your lungs, it can form in other organs, such as the breasts, stomach, or prostate.
In this article, we look at why the classification system was changed and examine the new types of lung cancers that replaced BAC.
The two main categories of lung cancer are small cell lung cancer and non-small cell lung cancer. They’re diagnosed based on the microscopic appearance of cancer cells. Non-small cell lung cancers are separated into three subcategories:
Formerly, BAC referred to a specific type of adenocarcinoma. It used to be divided into even further subcategories called mucinous or non-mucinous BAC.
The mucinous form tended to cause multiple groups of cancer cells whereas the non-mucinous form tended to create a solitary tumor.
The term “bronchoalveolar carcinoma (BAC)” has been replaced with “adenocarcinoma with a lepidic growth.” A
Invasive mucinous adenocarcinoma is also a new category that was previously under BAC, and is one that has a non-lepidic growth pattern.
These types of adenocarcinomas are classified into three categories:
- Adenocarcinoma in situ. These cancers are less than
3 centimeters and grow in solitary tumors showing entirely lepidic growth. This type of cancer is closest to the previous definition of bronchioalveolar carcinoma. - Minimally invasive adenocarcinoma. These cancers are smaller than 3 centimeters and grow in solitary tumors with primarily lepidic growth and less than 5 millimeters of invasion. They haven’t invaded blood vessels, supporting connective tissue, or the lining of the lungs.
- Lepidic predominant adenocarcinoma. These cancers have lepidic growth and either more than 5 millimeters of invasion or evidence of invasion into blood vessels, the lining of the lungs, or the lymph system.
Adenocarcinomas with lepidic growth make up about
| Adenocarcinoma | Squamous cell carcinoma | Large cell lung cancer | Small cell lung cancer | |
|---|---|---|---|---|
| Cells affected | mucus-producing cells | flat cells lining the airways called squamous cells | anywhere throughout the lungs | anywhere throughout the lungs |
| Prevalence | about | |||
| Risk factors | • primarily occur in people who smoke or have smoked • most common type in people who don’t smoke • more likely to occur in younger people than other types | • more than • reoccurring lung infections • exposure to chemicals like asbestos and arsenic | • smoking • exposure to radon, asbestos, and other chemicals | • smoking • exposure to some chemicals like asbestos, arsenic, and soot |
| Symptoms | • persistent cough • coughing up blood • difficulty breathing | • persistent chest pain • shortness of breath that doesn’t get better • reoccurring lung infections | • persistent cough • coughing up blood • chest pain | • symptoms tend to onset rapidly • coughing • shortness of breath • coughing up blood |
| Behavior | • more likely to be found before it’s spread • tends to be found in the outer part of lung | • tends to be found in the central part of lungs | • tends to grow quickly | • tends to grow and spread faster than other types |
| Outlook | • adenocarcinoma in situ and minimally invasive adenocarcinoma tend to have a very good outlook | • tends to have a better outlook than large cell carcinoma and small cell lung cancer | • often hard to treat because of fast growth | • tends to have a poor outlook • cancer returns in |
Traditionally, BAC was known as the “mystery” lung cancer since less was known about it than other types of non-small cell cancers.
Minimally invasive adenocarcinoma and adenocarcinoma in situ make up about 2 to 14 percent of lung cancers. They tend to occur most often in:
- nonsmokers
- women
- Asian people
Other risk factors include:
- tuberculosis scar
- pulmonary infarction (dead part of lung from a lack of blood flow)
- scleroderma
Most people with adenocarcinoma in situ have no symptoms.
Another 17 percent had excessive mucus production in their lungs and 10 percent had nonspecific chest pain.
It’s also been reported that some people can have frothy secretions up to several liters per day. This can lead to electrolyte imbalance and a poorer outlook.
Other
Symptoms of lung cancer can overlap with pneumonia, but the main difference is that lung cancer symptoms tend to come on slowly, while pneumonia causes symptoms shortly after an infection develops.
The process of diagnosing most types of lung cancers is similar. Diagnosis often starts with a doctor taking an X-ray of your lungs to screen for a potential tumor. A CT scan may also be used to search for cells that may not be identified with X-rays.
A tissue biopsy is needed for a doctor to confirm the diagnosis. A type of biopsy called a frozen section biopsy correctly identifies adenocarcinoma with lepidic growth in
Treatment for the formally known BAC usually consists of surgical removal using either a lobectomy or pneumonectomy. A lobectomy is when an entire lung lobe is removed. A pneumonectomy is when an entire lung is removed.
Chemotherapy and radiation therapy are options for people who are not good candidates for surgery.
Survival statistics can give you a rough idea of what to expect from your cancer. But your chances of survival can vary widely depending on factors such as:
- your overall health
- how far your cancer has spread
- your age
Your cancer team can give you the best idea of what to expect.
People with minimally invasive adenocarcinoma and adenocarcinoma in situ have excellent outlooks. When the cancer is surgically removed, they have nearly a 100 percent survival rate.
In a
“Bronchoalveolar carcinoma (BAC)” is an obsolete term. This type of lung cancer has been separated into other types to better differentiate between aggressive and nonaggressive forms.
Adenocarcinoma in situ is the type of cancer most similar to the previous definition of bronchoalveolar carcinoma. People with this cancer have a very good outlook with a survival rate of almost 100 percent.
You can talk with your cancer team to develop a treatment plan. Treatment usually consists of surgical removal of part of your lung.