Lung cancer is the leading cause of death among men and women. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined, according to the American Cancer Society, which estimates more than 220,000 new cases of lung cancer will be diagnosed in 2015.
There are three main types of lung cancer. The most common is non-small cell lung cancer, which includes squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. Next common is small cell lung cancer, or oat cell cancer, which tends to spread rapidly. Lung carcinoid tumors, or lung neuroendocrine tumors, are less common. They grow slowly and tend to be confined to the lung.
Some oncologists estimate just 10% of lung cancers are identified upon chest x-ray in patients with no obvious symptoms. The most common symptoms of lung cancer include a persistent, worsening cough; chest pain that increases with deep breathing, coughing or laughing; hoarseness; coughing up blood or reddish-brown sputum; shortness of breath; wheezing; weakness; weight loss; or bronchitis/pneumonia that does not resolve. If lung cancer spreads or metastasizes, it may cause bone pain, changes to the nervous system, or lumps near the neck or collarbone. Tumors in the upper right lung or nearby lymph nodes may press on the superior vena cava, the large vein that carries blood from the head and upper extremities to the heart, causing swelling in the upper body, headaches, dizziness, or altered consciousness. Cancers in the upper lungs may cause severe shoulder pain or affect nerves in the eye and face causing a triad of symptoms known as Horner syndrome: a single drooping eyelid, a smaller pupil in the same eye, and limited or no sweating on the affected side of the face.
Paraneoplastic syndromes, caused when lung cancers produce chemicals similar to hormones that trigger problems with distant tissues and organs, such as water retention in the kidneys, excessive cortisol secretion, breast growth in men (gynecomastia), or a wide variety of neurologic problems, may present the first suspicion signs of lung cancer.
Smoking is responsible for 80% of lung cancer deaths, according to the American Cancer Society. Second-hand smoke is responsible for thousands of lung-cancer deaths. Work-related exposure to asbestos, radon, arsenic, chromium, nickel, vinyl chloride and ionizing radiation may increase a person’s risk for developing lung cancer. People with existing lung diseases, such as chronic obstructive pulmonary disease and tuberculosis, also have an increased risk for lung cancer.
As with most cancers, early detection provides the best chance for curative surgery. The National Lung Screening Trial recently found that compared with chest x-rays, spiral CT scans performed on people at high risk for developing cancer due to their smoking history lowered their risk of death from lung cancer.
Diagnosing lung cancer may begin with an x-ray of the lungs to identify an abnormal mass or nodule. A CT scan is better equipped to reveal small lesions on the lungs. Positron emission technology (PET) scans are useful to confirm the placement and spread of tumors. Sputum samples may reveal lung cancer cells, or a biopsy to remove a tissue sample for examination under a microscope by a pathologist may be required to confirm a diagnosis. A biopsy may be taken with a needle biopsy inserted through the chest into the lung, an open biopsy using a surgical incision in the chest, during bronchoscopy, when the doctor passes a lighted tube down the throat and into the lungs, or during thoracoscopy, when a thin tube passes through the chest wall into the lungs, pleura (membranes lining the lungs and chest cavity), or mediastinum (area between the lungs).
Surgical removal of the cancerous tissue is usually the first-line treatment for non-small cell carcinoma, although advanced stages may require radiotherapy, chemotherapy, and palliative care. Some studies suggest preoperative chemotherapy improves survival in patients with non-small cell carcinoma. Chemotherapy, sometimes combined with radiation, is typically used to treat small cell carcinoma.
Radiation therapy may be administered to treat lung cancer or relieve associated symptoms. External beam radiation may cause skin irritation, fatigue, and diarrhea. Internal radiation therapy using implanted radioactive seeds may also cause bleeding, infection, or risk of injury to healthy tissue.
Targeted therapy identifies specific genes, proteins, or tissue environments that promote cancer growth and survival, and blocks those targets to inhibit the growth and spread of cancer cells. Certain lung cancers that are associated with the vascular endothelial growth factor (VEGF) protein may respond to the anti-VEGF agent bevacizumab, which, when combined with chemotherapy, has shown increased survival rates in some advanced cancers.
Many clinical trials are underway to study the best approaches for preventing, diagnosing, and treating lung cancer, including testing sputum samples for cancer cells and identifying DNA changes specific to the development of lung cancer.
Find support groups, studies, ways to quit smoking, research and access to clinical trials for lung cancer at the American Lung Association.
Mobile Molecular Imaging is a designated ACR Lung Cancer Screening Center.