Small Cell Lung Cancer
The less common form of lung cancer is known as small cell or oat cell lung cancer. It generally originates in areas surrounding the bronchi, which are the airways that connect the windpipe and lungs, and then spreads to the glands known as the bronchial submucosa. Small cell lung cancer (SCLC) metastasizes in the early stages of the disease and infiltrates the lymph nodes in the space between the lungs, bones, liver, adrenal glands, and brain.
In addition, the patient may also develop certain syndromes such as:
- Inappropriate secretion of antidiuretic hormone – This condition causes the salt level in blood serum to fall too low possibly resulting in too much fluid in the blood.
- Ectopic adrenocorticotropic hormone production – The hormone adrenocorticotropic is produced by the cancer cells rather than the pituitary gland. It causes a number of symptoms including a fattening of the face and neck, puffy eyes and a ruddy complexion.
- Lambert-Eaton syndrome – This causes muscle weakness.
Causes of SCLC
The following three activates have been associated with developing the disease:
- Smoking – This is the primary cause. Approximately 98 percent of all SCLC patients are or were smokers. Patients who are current smokers can improve their prognosis by stopping.
- Uranium mining – If the patient was a miner and a smoker, the incidence rate for developing SCLC increases.
- Radon exposure – Decaying uranium creates radon, which creates additional risk of developing the disease.
Research Shows Smoking Cessation Affects Prognosis
In a study titled “Influence of Smoking Cessation after Diagnosis of Early Stage Lung Cancer on Prognosis: Systematic Review of Observational Studies with Meta-Analysis”, published January 21, 2010 in BMJ, researchers evaluated how much smoking cessation affected survival in early stage lung cancer patients.
They searched several databases to find studies that measured the effect of stopping smoking after diagnosis of lung cancer on prognostic outcomes. Ten studies were included in their analysis, nine of which studied patients with early stage cancer.
The researchers found that continued smoking was associated with a significant increase in death from all causes, development of a second primary tumor, and recurrence in early stage small cell lung cancer. In addition, life tables constructed by the researchers estimated that 29 percent of 65-year old continuing smokers with SCLC would survive for five years as compared with 63 percent of those who stopped.
Small Cell Lung Cancer Prognosis
Nearly 65-70 percent of SCLC patients present with extensive disease at the initial diagnosis, which is incurable. If left untreated, the average survival time is six weeks. However, patients who present with early stage SCLC who are left untreated have an average survival time of 12 weeks.
The average survival of patients with SCLC who are treated with multimodality therapy are:
- Twenty months, a 2-year survival rate of 45 percent and a 5-year survival rate of 20 percent for early stage disease
- Twelve months and a 2-year survival rate of 4.6 percent for late stage disease
Patients who spend less than 50 percent of the time they are awake walking and those with 10 percent or more weight loss in six months worsen their prognosis.