Sunday, February 7, 2010

Lung cancer when radon invites himself home

Radon is a naturally occurring radioactive gas accounts for 9% of annual deaths from lung cancer in Europe. This carcinogen kills miners for centuries. But it is also present in our homes, where, even at low doses, it is particularly dangerous.

Radon is a carcinogen

For the French population exposure to radon is a major source of exposure to ionizing radiation. Radon is a radioactive gas that is naturally concentrated in poorly ventilated habitats. And we spend 90% of our lives in buildings, 70% at home. But radon is a lung carcinogen. He represents the 2nd cause of lung cancer. Although it lags far behind smoking, radon is responsible for approximately 9% of deaths from lung cancer in Europe. In France, the annual number of deaths from lung cancer is attributable to residential exposure to radon vary from 1234 to 2913, ie 5 to 12% of the 25,134 deaths from lung cancer in France.

Low doses of radon enough ...

According to one analysis identified in an article published in the Weekly Epidemiological Bulletin (BEH), the risk of lung cancer increases by 8.4% for every increase of 100 Bq/m3 the measured concentration of radon, which is adjusted an increase of 16%. But in the homes of people with cancer, the average concentration of radon is 104 Bq/m3 cons 97 Bq/m3 in the control group. Thus, most deaths are attributable to exposures well below 200 Bq/m3: 47% occur among 76% of French who are exposed to concentrations at 0 and 99 Bq/m3, 27% among those exposed to 9% over 200 Bq/m3. If we divided the subjects into groups according to concentrations of radon to which they are exposed, we find a linear relationship between cancer risk and cumulative dose. In other words, there is no threshold of dangerousness. The risk is almost the same for concentrations between 100 and 200 Bq/m3 and for concentrations below 100 Bq/m3.

In France, the average exposure is 90 Bq/m3, with lower concentrations in urban areas than in rural areas. Some departments were classified with high potential for radon. This is particularly the case of Brittany and Corsica where radon is responsible for 20% of annual deaths from lung cancer.

Please note that smoking is a powerful co-risk factor, especially since it is ubiquitous.

Protection against radon

The impact of radon exposure on the health of the population requires the implementation of policy actions. The Nuclear Safety Authority (NSA) has developed an action plan for 2005-2008 interdepartmental coordinating the actions of various national bodies involved in this field. It is organized around 3 themes:

- Construct a new policy for risk management of radon in existing houses and new construction;
- Supporting and monitoring the implementation of regulations for managing the risk associated with radon in public places;
- Improve and disseminate knowledge about exposures and risks associated with radon.

Note that exposures can be significantly reduced in homes by means often simple:

* Increase the level of aeration.
* Breakdown under floors.
* Installation of barrier antiradon.
* Sealing of soils.
* Boucher cracks.
* Avoid porous materials.
* For new homes: building pressure with double ventilation system sumps and connected to an extractor to pump the radon coming from the basement to the outside.

Note that there are devices for measuring the concentration of radon in his apartment. They are "dosimeters" that can be purchased from one company that sells (Algade, Dosirad, Saphymo). You can also use a professional.

Statins: cholesterol cons and lung cancer!

Smokers who have too much cholesterol they have better luck? In any case they would more than other smokers. Why? Because they take a statin, an anti-cholesterol, and that this molecule also protects against lung cancer!

Statins and cancer

Smokers are the luckiest paradoxically those who suffer from high cholesterol because treatment confers protection against lung cancer.
The description of this new effect of statins is particularly interesting because except smoking cessation, we do not currently have any weapons preventive from this terrible cancer.

Lung cancer

Each year there are 28,000 new cases of lung cancer and nearly 150,000 deaths (or 26 times more than road fatalities). In 95% cases it is caused by tobacco. Smokers and former smokers are the most concerned, but also non-smokers from passive smoking victims.

A 55% reduction in risk of lung cancer in statin

This study examined a population of approximately 480,000 persons followed in a clinic for veterans between 1998 and 2004. Lung cancer was reported in 7280 of these subjects (1.5%) and 164,000 were receiving treatment with statins (34%). Among subjects in whom lung cancer was reported, 27% were taking a statin, against 34% of those without cancer. Regardless of all the risks that may affect the risk of lung cancer (smoking, age, sex, weight, diabetes, alcohol consumption ...), we see that taking a statin for more than 6 months is associated with a 55% reduction in risk of lung cancer. This effect of statins appears from treatment over 6 months. Then, it seems that more processing time is longer, the protective effect tends to increase. In contrast, the type of statin and dosage does not seem to intervene in this study.

These data are important and are similar to those obtained for other statins on cancer. Studies should continue on the protection afforded by statins against tumors. It is at least a good reason for motivation for those who take a statin daily.

Lung cancer: It also affects non-smokers

Lung cancer also affects people who have never smoked. However, the lung tumors of these patients are generally not the same as those of smokers.

Lung cancer is different in smokers and nonsmokers

If smoking is the most important risk factors for lung cancer, the disease also affects non smokers. It is estimated that 15% of patients with lung cancer have never smoked. However, as an increasing number of data suggests, lung cancer non-smokers are often different from those diagnosed in smokers: the abnormalities observed in cancer cells of these two categories of patients are not the same.

What are the risk factors of lung cancer among non-smokers?

Side risk factor, it is well established that passive smoking and exposure to radon pollution play an important role in the occurrence of lung cancer in nonsmokers. Exposure to asbestos, wood smoke and fumes of cooking oil could also pose a risk. However, all of these factors can explain only half of cases of lung cancers diagnosed among non-smokers.

The treatment of lung cancer is different there too?

Later treatment, it appears already that certain drugs are more targeted therapy effective in non-smokers. This is particularly the case of "inhibitors of EGFR (Epidermic Growth Factor Receptor). But a better understanding of the molecular characteristics of tumors developing in people who never smoked could lead to an improvement in their care. It would not only choose treatments best suited among those existing, but also to develop new therapeutic molecules specifically targeting tumors from smokers.