There are two major forms of lung cancer: SCLC and non-small cell lung cancer (NSCLC), which is far more common and carries a better outlook than SCLC.
Cancer cells associated with SCLC tend to be smaller and tumors progress relatively rapidly, making early detection and diagnosis challenging.
Causes and risk factors
Lung cancer may be caused by a variety of different factors, but tobacco or smoke exposure remains the leading cause.
A variety of factors influence the chances of developing lung cancer, but tobacco or smoke exposure is the leading cause of SCLC cases. In the United States, smoking is responsible for 83 percent of male lung cancer deaths and 76 percent of female deaths each year.
Most people who develop SCLC have a history of smoking or have been exposed to secondhand smoke, but not all. Some people with no history of smoking or smoke exposure will still develop lung cancer.
When cigarette smoke is inhaled, tiny particles damage lung tissues.
Anytime a cell must repair itself or regrow, there is a chance for things to go wrong. If certain mutations occur, a cell can become cancerous. With repeated smoke exposure and damage, the chances of a cancerous lung cell developing increase dramatically.
Age is a major risk factor for developing lung cancer. Roughly 98 percent of those diagnosed with lung cancer are over the age of 45. Roughly two-thirds of people who develop lung cancer are 65 or older.
Causes and risk factors for SCLC include:
- exposure to tobacco smoke
- exposure to radiation
- CT scans
- exposure to asbestos, tar, or soot
- exposure to diesel fuel
- exposure to nickel or beryllium
- living in areas with heavily polluted air
- arsenic exposure from drinking water
- HIV status
- beta carotene supplements combined with heavy smoking
Research is still underway to better understand the influence of gender, ethnicity, and race on lung cancer.
While black American men and women are more likely than white Americans to develop lung cancer, fewer develop SCLC. Rates for the latter are 15 percent less for men and 30 percent less for women.
Often symptoms do not begin until the tumor has spread. Many lung cancer symptoms can sometimes be mistaken for those of other conditions.
The location, size, and extent of the tumor greatly influence the chances of someone experiencing symptoms.
Symptoms of SCLC include:
- hoarseness or rough cough
- changes in cough pattern
- shortness of breath
- long-term chest infections
- chest pain or pain when breathing
- coughing up blood
- loss of appetite
- pain or difficulty swallowing
- swelling in the face or neck veins
- excess fluid in the lungs or lining of the heart
- high-pitched sound upon inhalation
If any of the above symptoms become long-term or troublesome, a person should see their doctor. People over 55, or with a history of heavy smoking or smoke exposure, should be monitored even if they are not experiencing symptoms.
After an initial examination by a healthcare professional, a CT scan may be required to determine the stage of SCLC.
A doctor will first complete a physical examination, review the person's history, and take blood, urine, or tissue samples, if required. A chest X-ray may also be taken.
Doctors may decide to continue monitoring people whose symptoms, personal history, or test results are cause for concern.
Depending on the results of this initial workup, a CT scan can be used to examine the chest, torso, and brain. A sputum cytology test, where phlegm and mucus are inspected under a microscope, can help spot cancerous cells.
A biopsy, where cells are removed from the lungs to be examined by pathologists, may also be performed. Lung biopsies are divided into surgical and nonsurgical options.
The most commonly used and least invasive form of biopsy is fine needle aspiration, a nonsurgical option where general anesthesia is used.
Once a cancer diagnosis has been made, the stage of the cancer must be established to determine the best treatment plan.
Tests used to determine SCLC stage include:
- CT scan of upper body and pelvis
- bone scan
- bone marrow aspiration
- PET scans
- MRI of brain
- further biopsy
Many of these procedures and tests are also used to determine if treatments are working and to monitor cases long-term.
Stages of SCLC
There are generally four recognized stages of lung cancer, ranging from 1 to 4.
- Stage 1 cancers are confined to the lung. Tumors are typically 2 inches or less in diameter.
- Stage 2 cancers involve tumors that have exceeded 2 inches in diameter or have spread to surrounding tissues. The lymph nodes may be involved.
- Stage 3 cancers are defined by large tumors that have spread to other organs neighboring the lungs or smaller tumors in lymph nodes further away from the lungs.
- Stage 4 cancers involve tumors that have spread far beyond the lungs to affect more distant regions of the body.
In SCLC cases, additional stages defined as "limited" and "extensive" are used to describe whether the cancer is present in one or both lungs.
Limited stage cancer
In the limited stage, SCLC tumors are restricted to one lung and any affected lymph nodes will be on the same side of the chest. Because limited cases of SCLC can be targeted within a single radiation field, they are often treated with both radiation and chemotherapy.
About one in three SCLC cases are in the limited stage when first diagnosed.
Extensive stage cancer
In the extensive stage, both lungs are affected, as are other parts of the chest and sometimes body. An SCLC case may also be considered in the extensive stage when the cancer has spread to the fluid surrounding the lungs.
About two in three SCLC cases are in the extensive stage when diagnosed.
Treatments and outlook
SCLC may be treated with a combination of treatments including radiation, surgery, and chemotherapy.
Because SCLC cases are often diagnosed late in the course of the disease, aggressive treatment plans are often used.
When possible, SCLC is treated with a combination of chemotherapy, radiation, and surgery. Different specialists will work together to find the best course of action for each case.
A range of medications will be prescribed to help manage the symptoms. Nursing care may also be ordered.
Chemotherapy given orally or intravenously, alongside radiation therapy, is the preferred treatment for SCLC because of how quickly the tumors grow and spread. Fortunately, most SCLC cases respond well to radiation therapy, at least initially.
In limited stage SCLC cases, radiation therapy may also be used after 3-4 months of initial chemotherapy.
Common surgery options include:
- segmental, wedge, or sleeve resection to remove the affected part of lung
- lobectomy to remove one lung lobe
- bilobectomy to remove two lung lobes
- pneumonectomy to remove the whole lung
- lymph node removal
The cancer stage, the person's gender, age, family history, lifestyle habits, and general health will influence the chances of recovery for a person with SCLC.
The outlook for SCLC varies according to the individual and the stage of the cancer, but the average 5-year survival rate is 7 percent.
For SCLC cases in the limited stage, the relative 5-year survival rate is 31 percent. For SCLC cancers in the extensive stage, the relative survival rate varies from 8-19 percent. Stage 4 SCLC cancers have a 5-year survival rate of 2 percent.
It is important for people to keep in mind that each SCLC case is unique while statistics are averages. While they should be used with caution, lung cancer staging calculators exist.
Complementary therapies are those used alongside conventional medical therapies and may help manage SCLC symptoms.
Complementary therapies and lifestyle recommendations include:
- nutritional supplements
- guided meditation
- avoiding non-essential daily tasks to save energy
Alternative therapies are not meant to replace conventional therapies. Anyone thinking about an alternative treatment should discuss it first with a doctor.
Despite research, there are no treatments available today to cure SCLC outright. Many clinical trials exist that offer people new options and the number of such trials continues to grow.