Bronchoalveolar lung cancer
Bronchoalveolar lung cancer, also referred to as bronchioloalveolar carcinoma, is a specific subtype of non-small-cell lung cancer (NSCLC) that originates in the alveoli, the tiny air sacs in the lungs. This cancer can manifest as a single tumor or multiple tumors and has a propensity to grow quickly in a pneumonia-like manner, but it is less likely to spread beyond the lungs compared to other lung cancer types. Key risk factors include smoking, secondhand smoke exposure, environmental pollutants, and certain inherited conditions, with a significant portion of cases occurring in nonsmokers, particularly women.
Symptoms of bronchoalveolar lung cancer often include persistent cough, shortness of breath, wheezing, chest pain, and hemoptysis (coughing up blood). Diagnosis typically involves imaging tests such as chest X-rays and CT scans, as well as biopsies to confirm the cancer type. Staging of the cancer is vital for determining treatment options, which may include surgery, chemotherapy, and radiation therapy. Research continues to advance in the understanding and management of bronchoalveolar lung cancer, with efforts aimed at improving early detection and exploring new treatment modalities. Overall, avoiding smoking and exposure to harmful substances remains crucial for prevention.
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Bronchoalveolar lung cancer
ALSO KNOWN AS: Non-small-cell lung cancer (NSCLC), bronchioloalveolar lung cancer, lung adenocarcinoma
RELATED CONDITIONS: Pleural effusion, pneumonia
DEFINITION: Bronchoalveolar lung cancer is a type of NSCLC that arises in the alveoli (the air sacs of the lung). It can begin in a single site or multiple sites or spread rapidly as a pneumonic form. Bronchoalveolar lung cancer is less likely than other types of NSCLC to spread beyond the lungs.
Risk factors: The most common cause of lung cancer is smoking cigarettes. Another major cause is exposure to secondhand smoke. Other risk factors include exposure to radon gas or asbestos, environmental pollution, tuberculosis, lung disease, and an inherited predisposition to lung cancer.
Etiology and the disease process: With bronchoalveolar lung cancer, cells in the alveoli begin to grow wildly. As they grow, they progress along the alveolar walls. Multiple sites may develop and then converge to consolidate some areas of the lungs. An obstructed area of the lung may become pneumonic.
Incidence: NSCLCs account for about 75 percent of all lung cancers. Bronchoalveolar lung cancer makes up about 2 to 3 percent of this group. Although 10 percent of patients with lung cancer in the United States are nonsmokers, 25 to 30 percent of patients with bronchoalveolar lung cancer are nonsmokers. It is more common in women.
Symptoms: The symptoms of bronchoalveolar cancer are coughing, shortness of breath, wheezing, chest pain, large amounts of watery sputum, and hemoptysis (coughing up blood). On physical examination, the lungs are dull to percussion (tapping on the chest wall), and breath sounds may be weak or absent on auscultation (listening with a stethoscope). If the tumor is pressing on a nerve, it can cause shoulder pain or hoarseness.
Screening and diagnosis: Currently, no accurate, inexpensive screening test for bronchoalveolar lung cancer exists. Researchers are working to develop such a test by examining a marker in the blood and also by analyzing breath.
To diagnose lung cancer, pulmonary function tests and a chest X-ray may be performed. Chest X rays can demonstrate most lung cancers, except the very small ones. More sensitive tests are computed tomography (CT) scans, magnetic resonance imaging (MRI), and positron emission tomography (PET) scans.
A biopsy of the tumor must be performed to differentiate between the types of lung cancer. Bronchoscopy, thoracoscopy, or mediastinoscopy may be performed to examine pulmonary secretions and the lymph nodes of the lung. If the cancer exists on the periphery of the lung, a needle biopsy through the chest wall may be necessary. If none of these procedures is effective in determining the type of lung cancer, a surgical procedure called a thoracotomy (opening the chest) can be performed.
The actual diagnosis of bronchoalveolar lung cancer is made by the pathologist, who examines the tumor cells under a microscope. The pathologist identifies the type of lung cancer and stages the cancer. All NSCLCs are staged similarly, using numeric tumor grading and the TNM (tumor/lymph node/metastasis) stages. The stages are as follows:
- Stage IA, T1 N0 M0: The tumor is less than 3 centimeters (cm), and there is no lymph node involvement or metastases.
- Stage IB, T2 N0 M0: The tumor is greater than 3 cm, but it has not spread beyond the lung.
- Stage IIA, T1 N1 M0: The tumor is less than 3 cm, and it is spread to local lymph nodes.
- Stage IIB, T2 N1 M0, or T3 N0 M0: Either the tumor is greater than 3 cm, or it has spread into the outside of the lungs, the chest cavity, or the pericardium (sac around the heart).
- Stage IIIA, T 1-3 N2 M0, or T3 N1 M0: Either the cancer has spread to distant lymph nodes but has not metastasized, or the cancer has spread into adjacent tissues and muscles and has spread to local lymph nodes.
- Stage IIIB, T4 N3 M0: Either the cancer has spread to nearby organs, or it has spread to distant lymph nodes but has not metastasized.
- Stage IV, M1: The cancer has metastasized to distant organs.
Treatment and therapy: Lung cancer treatment can include surgery, chemotherapy, and radiation. To remove a bronchoalveolar tumor, the surgeon can perform a wedge resection, a lobectomy, or a pneumonectomy. Chemotherapy for lung cancers is effective only 35 percent of the time. The most commonly used drugs are combinations of cisplatin (Platinol), carboplatin (Paraplatin), vinorelbine (Navelbine), vincristine (Oncovin), vinblastine (Velban), paclitaxel (Taxol), docetaxel (Taxotere), and gemcitabine (Gemzar). Newer chemotherapy drugs that interfere with cell growth and reproduction and angiogenesis (formation of new blood vessels) are being used. They are gefitinib (Iressa), erlotinib (Tarceva), and bevacizumab (Avastin).
Radiation therapy for bronchoalveolar lung cancer is not effective as a cure, so it is reserved for treatment when surgery is not possible.
Prognosis, prevention, and outcomes: Patients with lower-stage cancers survive longer than those with high-stage cancers. Research has shown that patients who have never smoked respond better to treatments for bronchoalveolar cancer. The best way to avoid lung cancer is by not smoking and by avoiding exposure to secondhand smoke.
Patients with lower-stage cancers survive longer than those with high-stage cancers. Research has shown that patients who have never smoked respond better to treatments for bronchoalveolar cancer. The best way to avoid lung cancer is by not smoking and by avoiding exposure to secondhand smoke.
As of the mid-2020s, several advances have been made to address bronchoalveolar and other lung cancers. These include methods for earlier detection of lung cancer and screening candidates who might have a predisposition to this disease. Enhancements in blood markers seek to do likewise. CT scans are now being used to pre-screen heavy smokers who are likely to develop cancers. Computer algorithms and artificial intelligence may soon be more adept at searching and detecting cancer in patients than traditional radiology or pathology. New treatments, including immunotherapy, are being developed for lung cancers. Other targeted therapies may be able to replace other more invasive methods of combatting cancer.
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