What is Bronchioloalveolar Carcinoma?

Bronchioloalveolar CarcinomaBronchioloalveolar carcinoma (BAC) is a term which, as of July 2016, is no longer in use, but was once used to describe a certain subtype of lung adenocarcinoma (cancer that starts in the glandular cells of the lungs). Because some oncologists (cancer doctors) still use the term, this article will focus on the history and characteristics of what was once classified as BAC.

The Mystery Lung Cancer

When BAC was classified under this heading, it was often referred to as the “mystery” lung cancer. This was because, although it accounted for 2% to 14% of all lung cancers, less was known about this type of lung cancer compared to other types of non-small cell lung cancers (NSCLC).

What is BAC Called Now?

You may hear BAC being referred to as lepidic predominant adenocarcinoma, a term based on the typical growth pattern of the tumor. BAC starts in the cells nearest the alveoli (air sacs) of the lungs, spreading along the tissue that separates the alveoli or through the airways (air tubes) of the lungs. Unlike other types of lung cancer that spread to the pleura (lining) of the lungs and then to other regions of the body, BAC spreads predominantly within the lungs, appearing as a single spot in the outer part of the lungs or as scattered spots throughout the lungs.

Types of BAC

Bronchioloalveolar carcinoma is more likely to occur in non-smokers, women and in the eastern Asian population and seems to be increasing among younger, non-smoking women. There are two main types of BAC:

  • Mucinous BAC – more common and most often found in smokers.
  • Non-mucinous BAC – less common and often found in non-smokers.

Symptoms of BAC

BAC shares symptoms similar to those of other forms of lung cancer which include:

  • Persistent cough
  • Hemoptysis (coughing up blood)
  • Chest pain

However, BAC is also known as the “masquerader” as it’s not uncommon for it to be misdiagnosed as pneumonia or another lung disease before it’s finally diagnosed correctly.

Diagnosis of BAC

Unlike other forms of cancer that can be diagnosed using a CT or Pet scan, a diagnosis of bronchioloalveolar carcinoma requires your doctor to perform a fine needle aspiration biopsy, whereby a fine (long) needle is inserted through the skin and into the tumor for the purpose of aspirating (removing) a small sample. A pathologist will then look at the sample under a microscope to determine if the tumor is cancerous. If it is, she will also be able to determine what type of cancer it is just by looking at the sample.

Treatment of BAC

The treatment of choice for BAC is surgery. That said, if only a single tumor is to be removed, there’s an excellent chance that surgery will cure the cancer. BAC has also been treated with chemotherapy, but it doesn’t seem to respond as well to this treatment option as other lung cancers. Although controversial, some doctors may suggest adjuvant chemotherapy (combination of chemotherapy and surgery), especially if the tumor is more difficult to reach or it has spread. What’s more, many people with BAC have responded well to targeted therapies, treatment that targets specific genetic mutations within the tumor itself, without affecting the surrounding, healthy tissue. Lastly, lung transplant may be a possibility in the treatment of BAC, and if the cancer doesn’t reoccur in the transplanted lung, this may present another option for long-term survival.

Prognosis of BAC

When discovered early enough and there is only one tumor, BAC prognosis (how long a person lives after diagnosis) is better than with other types of NSCLC. One study showed that patients with tumors less than 3 centimeters in diameter who had surgical removal of the tumor had a five year survival rate of 100 percent. Survival rates in later stages of the disease vary significantly, especially if there are separate tumors in the same lobe, involvement of the lymph nodes or spread of the tumor to other regions of the body.

For more information about bronchioloalveolar carcinoma, talk to your primary health care provider.


Lynne Eldridge, MD. What Type of Lung Cancer is BAC (Bronchioloalveolar Carcinoma)? Verywell.com. Updated July 14, 2017.


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