Small Cell Lung Cancer FAQ

Small cell lung cancer (SCLC) is one of those terms that doctors toss around casually and can be unnerving for a patient or family member who doesn’t understand the term.  This FAQ collection is designed to provide the basic information about this lung cancer variant, why it differs from other forms of lung cancer, and what treatment methods are used to attack it.

Why is it called small cell lung cancer?

The “small cell” in small cell lung cancer is called an oat cell, different from other types of lung cancer cells in several respects; the name comes from the fact that it is smaller than other types of malignant cells.  Small cell cancer can also develop in other areas of the body.

What makes the “oat cell” different?

It is small, oval in shape, relatively flat, and holds almost no cytoplasm – a gel-like material that has all of the cell components except the nucleus within it.  Other types of lung cancer cells, which cause “non-small cell lung cancer,” are larger, of various shapes and hold substantial cytoplasm.

What is mixed small cell lung cancer?

Some cases of SCLC have two types of malignant cells: the oat cell and one of the non-small cell lung cancer types.  Mixed SCLC is still referred to as a small cell form of cancer and treated as such; the drugs used for chemotherapy will include those that target oat cells and others that are effective with whatever non-small cell is present.

Is SCLC a common form of lung cancer?

Small cell lung cancer accounts for about 15% of all lung cancer cases today.  That was not always the case; a few decades ago the percentage was higher.  Researchers believe the reason that the ratio has changed is the gradual reduction in smokers among the populace.

Why is it called an “aggressive” cancer?

Small cell lung cancer spreads rapidly.  It also moves into distant parts of the body early in the development of the disease, unlike other forms of lung cancer.  SCLC will spread to the lymph nodes near the lungs and from there be transported through the lymph system while the main tumor is still developing.  Many SCLC patients will exhibit no symptoms at all prior to diagnosis; 65 – 70% of all SCLC patients aren’t diagnosed until the disease has reached an advanced stage.

How is small cell lung cancer staged?

SCLC is staged with a simplified two-classification system, unlike most cancer staging protocols which use a four stage protocol.  SCLC is either “limited,” which means the disease is still confined to one side of the body and hasn’t spread beyond the lung and local lymph nodes; or “extensive,” which is the term for advanced SCLC that has spread to remote areas of the body.

What causes small cell lung cancer?

The foremost catalyst for SCLC is smoking; 98% of all people diagnosed with small cell lung cancer have a history of smoking.  The disease has also been linked to exposure to certain toxic substances: radon, a gas that develops from decaying radium; and asbestos which increases the likelihood of any lung cancer nine times.  The combination of asbestos and smoking increases the likelihood of developing lung cancer by fifty times.

How common is lung cancer in general?

Lung cancer is the second most common form of cancer in the United States, following prostate cancer.  In 2011 the National Cancer Institute expects a total of 221,000 new cases of lung cancer; applying the 15% formula for SCLC, that suggests there will be about 33,000 new cases of small cell lung cancer.

What are the symptoms for SCLC?

The symptoms for this disease are similar to those for non-small cell lung cancers; a persistent cough, chest pain, coughing up blood, shortness of breath, and wheezing.  About a quarter of all lung cancer cases are diagnosed before any symptoms appear.  SCLC can also bring on “paraneoplastic syndromes;” these conditions are a consequence of the presence of cancer, but not caused directly by the malignant cells.  They may be neurological, causing dizziness, difficulty with balance,  slurred speech; or they may develop in the gastrointestinal system or other internal organs.

How is SCLC diagnosed?

Physicians use a variety of tests to identify small cell lung cancer.  The initial exam is usually an imaging process, either a chest X-ray or a MRI study, a CT scan, or a PET scan.  If a tumor is apparent in the images, the tools used to decide what type of lung cancer it is include a needle biopsy, an analysis of sputum, thoracentesis, which involves extracting fluid from around the lungs and testing for malignancy, and if the tumor is in the bronchi as most SCLC tumors are, a bronchoscopy is performed.

How is SCLC treated?

The two treatment modalities employed with small cell lung cancer are chemotherapy and radiation.  Usually they are use in conjunction with one another, but chemotherapy is the primary treatment mode for most cases.  Because the large majority of SCLC cases are diagnosed at the advanced stage the treatment must be systemic in nature, attacking the malignant cells in several parts of the body.  Radiation may be used on the central tumor and in selected areas where it can have an impact on remote tumors that have developed.

Why don’t SCLC doctors use surgery?

The unfortunate fact that most small cell lung cancer cases have spread through the body when diagnosed makes surgery impractical in most cases.  In those rare instances when an early diagnosis occurs there may be surgery to remove the tumor that has developed in the lung.  Surgery is so rare in SCLC treatments that it is often not mentioned as an option.

Is treatment for SCLC effective?

One of the distinguishing factors for the oat cell is its dramatic response to both chemotherapy and radiation.  Each form of treatment is extremely effective; it is not unusual even with extensive cases of SCLC to see all evidence of malignant cells eliminated during the first round of treatment.  Unfortunately relapse usually occurs in a matter of months and the cancer returns.

How is it different from other forms of lung cancer?

SCLC grows more rapidly than non-small cell forms of lung cancer.  It also metastasizes to distant parts of the body much earlier in the disease development process than is the case with the more common forms of the disease.  SCLC is probably more responsive to chemotherapy and radiation than non-small cell lung cancer; however it is also more likely to come out of remission relatively quickly.

Are there clinical trials for SCLC?

Yes, there are clinical trials for every type of lung cancer and small cell lung cancer is no exception.  A recent look at the clinical trial database maintained by the National Cancer Institute showed nearly 150 clinical trials underway for some aspect of SCLC.  There has been a lot of experimentation with new methods of delivering radiation to malignant cells, as an example.

Can the disease be treated if it returns?

The treatment for recurring small cell lung cancer is the same as when the disease is diagnosed: chemotherapy and radiation.  Generally the disease is not as responsive to chemotherapy the second time around.

What is the average age of diagnosis?

The average age for diagnosis of all types of lung cancer is 68 years.  It is usually diagnosed in the later stages of life which means that other medical conditions can both mask symptoms and complicate treatment.  Cases that involve both asbestos and smoking may be impacted by the extremely long latency period for all types of asbestos related diseases.

What are the survival rates for SCLC?

The survival rates for limited small cell lung cancer are a median of 20 months, with 45% of patients surviving at least 2 years and 20% of patients reaching five years.  For extensive or advanced SCLC the median survival rate is 6-12 months.

Are there new treatments being developed

There are new chemotherapy drugs in the pipeline all the time.  The clinical trial process takes years; however lung cancer is such a widespread disease that several drug companies have made it a priority, using recent research in gene targeting for some of their products.  Traditional radiation therapy has expanded to include intensity-modulated radiation therapy (IMRT) which uses computer controlled linear accelerators to apply radiation in precise doses to a very small area.

Are clinical trials worthwhile?

If a clinical trial is underway with a site in your area it is worth looking into.  For small cell lung cancer the trial will most likely be for a new chemotherapy drug which can be a reason for hope.  In many cases the company conducting the clinical trial will pay for some or all of a patient’s treatment costs in return for participation.