What is Lung Cancer?
Lung cancer is one of the most common forms of cancer in the world. With the exception of skin cancer, lung cancer is now the number one cancer in the USA. In the UK it’s the third most common cancer (after skin and breast cancer).
Unfortunately in the majority of cases this type of cancer is self inflicted – smoking and passive smoking cause nine out of ten lung cancers. That said, it’s therefore one of the most preventable types of cancer. But despite being avoidable, it’s one of the most difficult cancers to treat because symptoms don’t normally appear until the disease has got a firm grip.
Despite the huge advances in treatment over the past few decades survival rates are incredibly low – only about 14% of all people who develop lung cancer are alive after five years. Even more frightening is that 80% of people die within a year of being diagnosed.
How does lung cancer occur?
Like any cancer, lung cancer occurs when the normal cells for some reason begin to grow and multiply uncontrollably. In this case the cells lining the lungs, the bronchi (air passages) or trachea (windpipe) divide up into clumps which form tumors.
The majority of lung cancers start in the bronchi which is why another term for lung cancer is bronchogenic cancer. They usually develop over a very long period of time, starting as pre cancerous changes in the lungs before progressing into full blown cancer.
As with any cancer, survival rates are far better if the disease can be caught early – but with lung cancer that’s rarely an option.
Lung cancer can also spread to the lymph nodes which will then transport it to other major organs in the body in a process called metastasis. The lungs are also a very common calling point for other forms of cancer from elsewhere in the body.
Types of Bronchogenic Cancer
Lung cancers are usually divided into two types – non small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). About 80% of lung cancers are NSCLCs and although SCLCs are less common they are far more aggressive and very likely to metastasize – in fact the cancer has usually spread to other parts of the body before being diagnosed. Having said that, both forms of lung cancer can spread rapidly and are difficult to treat. In many cases once lung cancer has been diagnosed it’s more a case of helping someone to live longer rather than curing the disease.
A small number of lung cancers (about 5%) are rare types such as carcinoid tumor or lymphoma.
Lung cancer is still the most common cause of male deaths from cancer. Smoking was very popular among men in the 50s, 60s and 70s and the cases being diagnosed today are the result of that trend.
Over the last decade there has also been an increase in the number of women being diagnosed thanks to a smoking boom among females in the 70s.
However over the last couple of years, particularly in the UK and America, the number of lung cancer cases are beginning to slowly drop indicating that a decade or so ago the messages regarding the dangers of smoking were getting through.