Approximately 175,000 people are diagnosed with lung cancer in the United States every year. The rate of lung cancer is dropping among men but increasing among women. This is because fewer men and more women now smoke. Smoking and second-hand smoke causes more than 85% of lung cancer. Lung cancer forms primarily in the cells lining the air passages, or bronchia, in the upper lungs.
Lung cancer is seldom caught early. The disease was once virtually incurable, but new treatments and technologies have improved the prognosis.
Types of Lung Cancer
Small Cell Lung Cancer
Approximately 20% of all lung cancer cases are small cell lung cancer, or SCLC. This is the fastest growing and spreading type of lung cancer. SCLC metastasize rapidly beyond the lungs to other parts of the body. SCLC is very strongly linked to smoking. Smokers account for 99% of SCLC patients.
Non-Small Cell Lung Cancer
Approximately 70-75% of lung cancer cases are non-small cell lung cancer, or NSCLC. There are three main types of NSCLC, which may occur individually or in combination.
Adenocarcinoma is the most common type of non-small cell lung cancer. It accounts for approximately half of all NSCLC, or 40% of all lung cancer. Although, like all lung cancer, adenocarcinoma is closely associated with smoking, it is the type of lung cancer non-smokers are most likely to get. Adenocarcinoma usually occurs in the outer part of the lungs and along the walls of the air sacks of the lungs.
Squamous Cell Carcinoma
Squamous Cell Carcinoma accounts for about 30% of non-small cell lung cancer. It usually occurs in the bronchial tube area toward the center of the lungs.
Large Cell Carcinoma
Large cell carcinoma are the least common type of non-small cell lung cancer. It accounts for 10-15% of NSCLC. Large cell carcinomas are called undifferentiated tumors because the cells lack the specific structure of other types of cancer cells. Large Cell Carcinoma tends to grow quickly and metastasize sooner than other NSCLCs.
Bronchial carcinoids are the only form of lung cancer which appear to be unrelated to smoking. They account for about 5% of lung cancers. Bronchial carcinoids grow and spread slower than other lung cancers.
Metastatic Cancer of the Lung
When cancers from other parts of the body spreads to the lungs, it is not lung cancer, but a metastatic cancer of the lung. These metastasized tumors have the same kind of cancer cells – and similar characteristics – as the original tumor.
Lung Cancer Risk Factors
To find out if you’re at risk for developing lung cancer, take this brief risk assessment.
Smoking is the greatest single risk factor for developing lung cancer. About 90% of lung cancer is a result of smoking.
- One-pack-a-day cigarette smoker = 25 times more likely to get lung cancer than a non-smoker.
- Cigar or pipe smoker = 5 times more likely to get lung cancer than a non-smoker.
- Quitting can eventually reduce the risk. Fifteen years after quitting, former smokers’ risk of getting lung cancer is about the same as non-smokers.
Breathing in smoke from smokers at home or at work increases the chance of getting lung cancer by about 25%. Young children’s lungs are especially susceptible to damage from second-hand smoke. If smokers avoid smoking around non-smokers or in rooms, automobiles or other enclosed spaces non-smokers use, they can reduce the risk of causing the non-smoker to get lung cancer from passive, or second-hand, smoke.
Asbestos was once widely used in the United States. Since 1989 most – but not all – industrial and construction uses of asbestos have been banned. Because of its widespread former use in insulation materials, many older buildings still contain asbestos. Working with or around asbestos greatly increases the risk of getting lung cancer. Smoking multiplies that risk.
- Working with or around asbestos = 5 times more likely to get lung cancer than average.
- Working with or around asbestos and smoking = 50-90 times more likely to get lung cancer than average.
- Meticulous care is using a respirator when working with or around asbestos may reduce the risk. Strict adherence to workplace regulations may also help.
Radon is the leading cause of lung cancer among non-smokers. It is a colorless, odorless, tasteless radioactive gas produced by the decay of uranium in the ground. Radon gas generally dissipates outdoors, but it can accumulate in dangerously high levels in buildings. Factors which may lead to high indoor air radon levels include:
- Geography. Radon levels vary significantly by location.
- Slab foundation
- Un-ventilated or not-fully-ventilated crawl space
- Sump pump
- Private well water
- Buildings over granite
The EPA has recommends a level of less than 4 picocuries per liter as safe. They estimate that approximately 6-7% of U. S. homes are above the safe level. Kits to test radon levels are available in most hardware stores. When an unsafe level is found it can be lowered by sealing the routes through which radon enters the house or increasing ventilation in the building to reduce the radon concentration.
Having a relative with lung cancer increases a person’s chance of getting lung cancer. This genetic susceptibility to the disease makes it especially important to be aware of lung cancer warning signs and to avoid smoking.
Lung Cancer Warning Signs
Possible symptoms or primary lung cancer may include:
- A new persistent cough
- Worsening of a chronic cough
- Persistent bronchitis
- Frequent respiratory infections
- Coughing up blood
- Chest pain
- Unexplained weight loss
- Unexplained fatigue
- Breathing problems or shortness of breath
When lung cancer has metastasized to other areas of the body, possible symptoms may include:
- Shoulder pain
- Difficulty swallowing
- Severe bone pain
- Blurred vision
- Weakness or loss of feeling in part of the body
Lung Cancer Diagnosis and Staging
The first step in lung cancer detection and diagnosis is a routine history and physical examination by a primary care physician. Learning about the patient’s symptoms and observing possible indicators such as difficulty breathing, bluish skin or nail bed clubbing may alert the physician to the possibility of lung disease.
The first step in determining if a mass is cancer or benign is a diagnostic image. One or several of these may be used:
The first diagnostic step is a chest X-ray. A chest X-ray can detect suspicious lung masses, but cannot be used to determine if they are cancerous or benign. Patients are exposed to small amounts of radiation during the X-ray procedure.
A computerized tomography (or CT or Cat) scan can provide a more-detailed image of the lung. CT scans are a series of X-rays combined by a computer in a cross-section view. They can be performed with injected contrast material to highlight lung tissue and suspicious masses. Since the basic imaging mechanism of a CT scan is X-rays, patients receive a low dose of radiation during the procedure. The radiation dosage is significantly lower with low-dose helical CT scans, but masses detected with this technology must be reexamined.
Magnetic resonance imaging (or MRI) scans uses magnetism, radio waves and computer image manipulation to produce an extremely detailed image without radiation. Because of the extremely powerful magnetism of MRI scanners they cannot be used on patients with any metal implants or pacemakers.
Positron-emission tomography (or PET) scans are three-dimensional images of the metabolic functioning of body tissues. PET scans can be used to determine the type of cells in a mass and to detect whether or not a tumor is growing. Patients receiving PET scans are injected with a radioactive drug with about as much radiation as two chest X-rays.
Biopsies are procedures in which a small amount of a suspicious mass is removed for examination by a pathologist. There are three main types of biopsy for suspected lung masses:
A surgical biopsy is a procedures in which patient’s chests is opened to gain access to a small sample of a suspected mass. The sample is analyzed by a pathologist while the surgery is proceeding, and all – or as much as possible – of the mass is usually removed during the operation, called a thoracotomy. A thoracotomy is a major surgical procedure performed under anesthetic in a hospital operating room.
In bronchoscopy a fiber-optic tube – called a bronchoscope – is inserted through the patient’s mouth or nose and passed through the trachea and bronchial tubes to the suspected area. The tube has a lens and light source which allow the physician to examine the lung mass. Frequently the bronchoscope has a sampling devise to retrieve a small section of the suspected mass for analysis. A bronchoscopy can be performed in an outpatient suite or a hospital operating room and requires a sedative and anesthetic.
Needle Aspiration or Core Biopsy
In needle aspiration (often called core biopsy) a thin needle is inserted into the suspected mass and a small sample withdrawn for analysis. Needle aspiration is performed on an outpatient basis and requires a local anesthetic.
In sputum cytology a pathologist examines the patient’s sputum under a microscope. The cells of centrally-located tumors are often present in sputum, and if they are, the pathologist can diagnose the condition by simple visual examination.
Lung Cancer Staging
Staging is the evaluation of the extent to which a lung cancer tumor has grown and/or spread. Different lung cancer treatments are specifically for various stages of the disease. The stages of non-small cell and small cell cancers are:
- NSCLC stage I – the cancer is only in the lung.
- NSCLC stage II – the cancer is confined to the chest area.
- NSCLC stage III – the cancer is confined to the chest, but the tumors are larger and more invasive.
- NSCLC stage IV – the cancer has spread beyond the chest to other parts of the body.
- Limited-stage SCLC – the cancer is confined to the chest.
- Extensive-stage SCLC – the cancer has spread beyond the chest to other parts of the body.
Lung Cancer Treatment Planning
Lung cancer treatment can involve a surgeon, medical oncologist, radiation oncologist, pulmonologist, pathologist and others caregivers in a precise and intricate sequence. Planning and coordinating the best possible sequence of care for each patient is critically important.
The Multidisciplinary Chest Conference/Clinic at Thompson Downtown
At Thompson Downtown, the cases of patients with chest disease are presented to a team of physicians and other medical professionals during a weekly chest conference. After the conference the patient may meet with individual specialists one at a time. In one afternoon a course of treatment can be agreed upon and scheduled. Participants may include:
- Medical oncologist
- Radiation oncologist
- Cardiothoracic Surgeon
- Licensed clinical social worker
- Genetic counselor
- Clinical trial nurse
- Nurse navigator
Throughout the process a multidisciplinary cancer care coordinator is available to be sure each patient understands the plan of care. At the conclusion of the multidisciplinary clinic the multidisciplinary cancer care coordinator helps schedule the planned care.
The Comprehensive Chest Clinic at Thompson at Methodist
At Thompson at Methodist the Comprehensive Chest Clinic eliminates any unnecessary delay in diagnosing and beginning treatment of possible chest cancers. As soon as a family doctor or other physician refers a patient to the Comprehensive Chest Clinic an appointment is set for an examination within the next two days. If additional an additional examination or diagnostic procedure (such as a biopsy) is needed, it is arranged quickly. A special care coordinator schedules appointments with any specialists who need to see the patient. Within one week of the original referral, all examinations are complete, a diagnosis is determined, a treatment plan is developed and treatment is scheduled to begin.
Lung Cancer Treatment
Lung cancer treatment is either curative (to eliminate the cancer) or palliative (to reduce pain and discomfort for patients whose cancer cannot be cured). In either case surgery, radiation, chemotherapy or a combination of two of the treatment types may be used.
Surgery is most often used to remove stage I non-small cell lung cancer tumors and some NSCLC stage II tumors. Surgery for lung cancer may involve removal of part of a lobe (wedge resection), removal of an entire lobe (lobectomy) or removal of an entire lung (pulmonectomy). Surgery is seldom performed on small cell lung cancer because the disease has usually spread beyond the lung by the time it is detected and diagnosed.
External Radiation Therapy
External radiation therapy is used in both curative and palliative treatment, alone and in combination with chemotherapy. In external radiation therapy a map of the tumor’s location is created with a CT scan, either before the treatment is planned or, with TomoTherapy, at the time of treatment, and then on subsequent visits the tumor is radiated from different angles to maximize the dose delivered to the tumor with minimum impact on surrounding healthy tissue.
Thompson Cancer Survival Center was one of the first facilities in the world to treat patients with intensity modulated radiation therapy. Since 1998 more than 1,000 patients have received IMRT treatment at Thompson. Now both Thompson Downtown and Thompson at Methodist offer this treatment. In IMRT the multileaf collimator reshapes the treatment field between individual doses of radiation, so the beam is matched to the shape of the tumor from all angles.
In high-dose-rate brachytherapy radioactive pellets are implanted into the tumor. The benefits of the technology are significant. Treatment time is reduced, affected areas receive a maximum dose and surrounding healthy tissue is spared.
Thompson at Methodist pioneered high-dose-rate brachytherapy in 1998, and has done more than 700 procedures with this technology. The HDR brachytherapy team here is the most experienced in the area
Thompson’s Downtown facility has the area’s first dedicated brachytherapy suite. The patient’s scan is made and all preparation for treatment is done right in the HDR brachytherapy suite. Since the patient doesn’t have to be transported from a separate CT room to the treatment area, the placement of the radioactive pellets is more precise. And with a dedicated suite, treatment can always be scheduled exactly when needed.
Both non-small cell and small cell lung cancer are treated with chemotherapy. This chemical treatment is especially effective in treating small cell lung cancer, and can increase patients’ expected survival by four or five times what it would be otherwise. The latest chemotherapy drugs are tested in clinical trials
Thompson is a world leader in photodynamic therapy, and is now the first facility in Tennessee – and one of the few in the world – using this technology to treat early endobronchial lung cancer.
The treatment is usually performed on an outpatient basis, has limited side effects and preserves healthy lung tissue.