How does CT screening increase the chance of cure of lung cancer – and lower the risk of dying of lung cancer?
Lung cancer is the most common cause of cancer death in both men and women. At present at least 150,000 people die of lung cancer in the U.S. each year and millions of others die, around the world.
As my career progressed, I came to realize that, despite the efforts of thousands of bright, hard working people and the constant addition of new drugs, treatment of lung cancer cured only a small percent (currently about 17%) of those with the disease.
The core problem is that, if lung cancer is diagnosed only after the patient develops symptoms (for example chest pain, shortness of breath or coughing blood) the disease is usually in an advanced stage, in most (75% or greater) cases, where treatment is difficult and cure uncommon.
It is much better to prevent a disease than to try to treat it. Unfortunately, most cases of lung cancer are caused by cigarette smoking. This is a very difficult problem because the tobacco industry has spent as much as 20 times more money to try to convince people to start and keep smoking, than public health does to try to convince young people from starting to smoke.
A second strategy is to try to get people who are already smoking to quit as quickly as possible. This is a wise strategy, but it has limited success. The tobacco companies ensure that their products contain nicotine, a very addictive substance that makes quitting difficult.
Another problem is that, even if a person stops smoking, damage (thousands of mutations) in DNA has already taken place and, although a person who quits lowers risk of lung cancer, a substantial risk still remains.
The third strategy – the one this site will focus on – is screening for early stage cancer detection. The goal of screening is to detect lung cancer – before – it causes symptoms, while it is still small in size, early in stage – and most important, still curable.
To understand what screening is, a few facts about cancer in general and about lung cancer specifically are in order.
In general, the smaller the size at which a primary cancer (T) is detected, the lower is the chance that it has spread (metastasized) to lymph nodes (N) or to other body organs distant from the lung (M).
The combination of T, N and M status is categorized in shorthand as “TNM”. TNM categories, in turn, lump lung cancers into stages 1-4 – in increasing severity. The reason that doctors “stage” cancers is to guide prognosis and treatment.
Stage 1 and 2 cancers can typically be treated with surgery or sometimes radiation therapy alone, while stage 3 and 4 lung cancers usually require “multimodality” treatment, for example chemotherapy plus radiation therapy or chemotherapy plus radiation therapy followed by surgery etc.
Unfortunately, in the case of lung cancer today, when we screen very few people, most (75-80%) cases detected with symptoms are in stage 3 and 4.
While as many as 30% of stage 3 lung cancers can be cured with multimodality treatments, stage 4 cancers have a very low cure rate.
Caption: Large lung cancer in the left lung with spread to lymph nodes in the right side of the chest – stage IIIB.
Caption: Lung cancer with metastasis to the brain – stage IV.
There is some good news. Most cancers in Stage 1 can be cured by surgery alone, or in some cases by radiation therapy alone.
It is also important that, the smaller the cancer is, within Stage 1, the higher is the chance of cure. For example, if a lung cancer can be diagnosed at 1 cm. In diameter, the chance of cure is better than 90%.
Unfortunately, in the absence of screening, only 15% of lung cancers are found in stage 1 and only a tiny fraction are 1 cm..
Can screening detect lung cancer in stage 1? Yes.
Can screening detect lung cancer at a small size e.g. 1 cm.? Yes.
Using computerized tomography (CT), lung cancer can be safely and efficiently be detected in Stage 1 in most cases. 
Caption: 9mm. Lung cancer in the right upper lobe detected by CT screening.
The good news is that, if you meet certain eligibility criteria set up by Medicare/Medicaid, the CT scan is free.
The bad news is, that despite this test having been available in the U.S. for more than 20 years, to date only about 4-6% of U.S. citizens -those determined to be at very high risk for lung cancer – have been screened.
The failure of our public health system to offer this life-saving test to those at risk has resulted in innumerable deaths.
In future pages, I will try to explain how this tragedy has unfolded and what we can do about it now, today, to help individuals at high risk of lung cancer (and their doctors) to understand benefits and possible risks of screening and how to go about participating in a high-quality screening program with the goal of preventing thousands of unnecessary deaths from lung cancer.