The lung cancer usually begins to form in the mid-fifties or sixties. The smoking is responsible for 80% to 90% of cases of lung cancer.
This cancer is particularly threatening because it can more easily spread to the rest of the body than other types of cancer. Indeed, all the blood passes through the lungs to be oxygenated, and the lungs are in close contact with several blood and lymphatic vessels. Lung cancer is all the more alarming because it is often discovered late. It is the leading cause of cancer deaths in Canada for both men and women.
The Canadian Cancer Society predicts there will be 24,100 new cases of lung cancer in 2010 in the country: 12 900 men and 11 200 women.
However, this cancer can be prevented very effectively by stopping smoking or smoking less.
causes Lung cancer
- The smoking .
- Exposure to second-hand smoke .
- Exposure to carcinogenic particles in the air , such as those from asbestos, arsenic, radon or air pollutants (carbon monoxide, ozone, etc.).
Some facts about smoking and second-hand smoke
- It was in the mid-1960s that the causal link between smoking and lung cancer was established with certainty.
- In Canada, tobacco control efforts have been successful: in 1965, half of Canadians aged 15 and over smoked, compared with 25% in 1999 and 18% in 2008.
- Through provincial legislation , Canadians are much less exposed to second-hand smoke in their workplace and in public places.
- Smoking is twice as prevalent among Aboriginal populations as it is among the general Canadian population.
- With the reduction of tobacco use, lung cancer has been declining since the mid-1980s in men . However, in women , this cancer has steadily increased since 1980 and is only beginning to stabilize.
Types Lung cancer
There are 2 types of lung cancer. They grow and spread differently in the body.
- Small cell lung cancer . This is the most dangerous form of lung cancer. About 20% of lung cancer cases occur in this form. At the time of diagnosis, the risk of cancer already spreading elsewhere in the body is high. It grows rapidly and is often impossible to treat with surgery. Instead, chemotherapy and radiotherapy are used.
- Non-small cell lung cancer. This form of lung cancer, which accounts for about 80% of cases , is more easily detected and treated than small cell cancer. It develops more slowly. This category includes 3 subgroups: adenocarcinoma , squamous cell carcinoma and undifferentiated large cell carcinoma . There are other forms, much rarer.
The lung cancer is among the deadliest, with pancreatic cancer . The survival rate of people with this cancer, 5 years after diagnosis, is 17% for women and 14% for men. Even if the person responds well to the treatment at first, relapses are common in the following years or months.
Lung cancer often clogs the airways, creating a breeding ground for respiratory infections, such as bronchitis or pneumonia .
As previously mentioned, cancer can spread to other parts of the body by metastasis . Generally, metastases will lodge in other parts of the lungs, and in the bones, brain or liver. They are more common in small cell lung cancer cases.
symptoms Lung cancer
Sometimes no symptoms are detectable. The most common symptoms are as follows. However, other health problems can also cause these symptoms.
- Cough that intensifies or does not go away (you have to pay attention to a worsening smoker’s cough).
- Constant chest pain, which gets worse when you cough or breathe deeply.
- Shortness of breath.
- Coughing up blood.
- Hoarse voice lasting more than 3 to 4 weeks.
- As the case may be: recurrent bronchitis or pneumonia, loss of weight and appetite, chronic fatigue, headache, bone pain, etc.
People at risk
- Smokers with a genetic predisposition to cancer . Experts argue that genetic factors may explain, for example, that some people smoke little and develop cancer, while others smoke a lot, but do not develop it.
- People with chronic lung disease , such as scleroderma , or who have fibrosis (scar tissue) in the lungs. The fibrosis can appear as a result of pneumonia or tuberculosis.
|Avoiding these factors helps reduce the risk of lung cancer. Nevertheless, most people who have a risk factor will not have this cancer. On the other hand, it happens that the disease is declared even in the absence of all these risk factors.|
Main risk factor
- Smoking the cigarette. By far, this is the most important risk factor. Smokers are 10 to 25 times more likely to develop lung cancer than non-smokers. For smoking two packs of cigarettes a day, the risk is 50 times higher. The risk depends on the age at which smoking began, the number of years and the amount of cigarettes consumed per day. Although lung cancer takes several years to develop, physiological changes in lung tissue are visible well before. The women who smoke may be slightly higher risk of lung cancer than men, for unknown reasons.About other types of cigarettes. “Exotic” cigarettes (kretek, bidi, etc.), often flavored, are safer than cigarettes. Some have no filter, others contain less tobacco, but more nicotine than regular cigarettes. It should be noted that chewing tobacco is one of the main causes of cancer of the mouth and throat.
|Light cigarettes: safer? According to experts at the Mayo Clinic in the United States, believe that we reduced the cancer risk by choosing low tar cigarettes or nicotine is often a mistake. This slight protective effect would be offset by the fact that the majority of people who smoke these cigarettes inhale the smoke more deeply, without realizing it, in order to obtain the same amount of nicotine.|
Other risk factors
- Smoking the pipe or the cigar. Their smoke would be as harmful to the lungs as that of the cigarette. However, pipe and cigar smokers generally smoke less frequently than cigarette smokers, which reduce the risk of cancer.
- Être fréquemment exposé à la fumée secondaire. Chez les non-fumeurs, il s’agit du principal facteur de risque de cancer du poumon. Vivre avec un fumeur augmente le risque, par un facteur de 1,25 à 2,5. Les enfants dont les parents fument on plus de risque de cancer de poumon à l’âge adulte.
- Being exposed to carcinogenic products in the course of a job. Carcinogens may cause genetic mutations that cause cancer. This is the case for workers exposed to asbestos (miners in an asbestos mine, construction workers), radon (in uranium mines), chromium (welders) or furnace vapors. gas . People in frequent contact with chemicals or minerals that may be inhaled ( arsenic , beryllium, vinyl chloride, nickel chromate, coal products, mustard gas, gasolinediesel exhausts, talc dust, etc.) that do not comply with safety measures also have an increased risk.
- Be exposed to carcinogens at home. Exposure to high levels of radon in the home increases the risk of lung cancer, especially for smokers. Radon is a radioactive gas naturally present in soil and rocks, resulting from the degradation of uranium. It is colorless and odorless . The risk occurs in homes built on soils containing uranium. Radon infiltrates basements through dirt floors, concrete walls (and even more if they are cracked), drains and sump pumps.
There is more radon in certain geographical areas. Radon is also found in high concentrations in soils contaminated by some industrial waste (uranium byproducts, phosphate mines). In the United States, one home in 15 would expose residents to unsafe radon rates and 12% of lung cancer cases would be attributable to radon. According to Health Canada, “radon levels are not high in homes in Canada”. Some Canadian cities are more affected than others. It is possible to measure the radon content of the air in your home. Canadians can consult a guide written for this purpose (see the Sites of Interest section). In France, a cartography has been carried out which indicates the average radon concentrations in the air of dwellings.
Exposure to asbestos , a fibrous mineral used as insulation in homes and buildings, also increases the risk of lung cancer. In homes, these insulators are not dangerous as long as they are not broken or handled in the open, which can be the case during renovations.
The wood stoves , if they are not waterproof, are fine sources of particles in the air of homes, particularly dust and ashes. Wood smoke contains more than 100 toxic substances, some of which are carcinogenic.
Note.In its natural form, talc can contain asbestos. However, since 1973, a Canadian law has required that consumer products containing talc (body, face and baby powders) be free of asbestos.
- Frequent exposure to air pollution Air pollution is thought to be responsible for 5% of mortality from cancer of the trachea, bronchi and lungs. Particles from the burning of coal , oil , natural gasand garbage incineration are responsible for this. This problem is of particular concern in the poorer and more densely populated countries, especially in Asia, but concerns, to some degree, all major cities.
- Consume small amounts of fruits and vegetables. Many studies ( cohort or case-control ) on dietary habits indicate a slightly lower risk for consumers of fruits and vegetables rich in beta-carotene (sweet potatoes, pumpkins, carrots, spinach and other vegetables). dark green, winter squash, etc.).
|According to epidemiological studies, beta-carotene consumed in the form of supplements is contraindicated in smoker. For more information, see the Complementary Approaches section.|
Potential risk factors
- Smoking marijuana. For now, evidence suggests that marijuana does not increase the risk of lung cancer. Marijuana smoke, or cannabis, although nicotine-free, contains many of the carcinogenic substances found in tobacco smoke. Researchers believe that the tetrahydrocannabinol (THC) found in marijuana smoke exert a protective effect, but more research was observed a deleterious effect. Marijuana smoke is often inhaled deeply and stored for a long time in the lungs. Some evidence suggests that marijuana may cause cancer of the mouth or throat.
- Smoking narghile (oriental pipe, water pipe, houka). The data is currently insufficient to know the impact of this practice on the risk of lung cancer. The amount of smoke smoked in the hookah is much lower than that found in cigarettes. In this regard, the position of the Canadian Cancer Society and the American Cancer Society is: “No amount of tobacco is safe”. Smoking narghile is a tradition in North Africa and the Middle East. The smoker inhales through a long pipe the flavored tobacco smoke. Although filtered by water, the smoke contains certain amounts of nicotine, carbon monoxide and other harmful substances.
|Basic preventive measures|
Main preventive measure Lung cancer
The most effective preventative way is definitely not to start smoking or quit. Reducing its consumption also reduces the risk of lung cancer.
Avoid second-hand smoke.
Avoid exposure to carcinogens in the workplace. Follow the precautionary measures specific to each product and do not bring your work clothes home.
Have a healthy diet, which includes 5 to 10 servings of fruits and vegetables a day. The preventive effect is also observed in smokers . It seems that people at risk should pay particular attention to include in their diet fruits and vegetables rich in beta-carotene (carrots, apricots, mangos, dark green vegetables, sweet potatoes, parsley, etc.) and crucifers ( cabbages of all kinds, watercress, turnips, radishes, etc.). Soybeans appear to have a protective effect. Foods rich in phytosterols to.
Avoid exposure to asbestos. Check if the insulation contains asbestos before starting renovations. If this is the case and you want to remove them, it is better to ask a professional to do it. Otherwise there is a risk of exposure to it seriously.
If necessary, measure the radon content of the air in your home. This can be helpful if your community is in one of the areas where radon levels are high. You can test the radon level inside the house with a device designed for this purpose, or by calling a private service. The radon concentration in the outdoor air varies from 5 to 15 Bq / m. The average radon concentration in indoor air varies greatly from country to country. In Canada, it fluctuates from 30 to 100 Bq / m. The authorities recommend that individuals take measures to correct the radon concentration when it exceeds 800 Bq / m. See the Sites of Interest section for radon concentrations in different geographic areas of North America.
Here are some measures to reduce radon exposure in homes at risk :
|In case of symptoms (unusual cough, shortness of breath, chest pain, etc.), mention it to your doctor, who will suggest various medical tests if necessary.
Some medical associations, such as the American College of Chest Physicians recommend lung cancer screening by Ct Scan under certain circumstances, such as smokers over 30 pack-years aged 55 to 74 years. But we must be aware of the high number of false positives, the morbidity associated with the investigations and the anxiety it causes in patients. A decision aid is available (in English).
In the study
|Measures to prevent aggravation and complications|
The treatment depends on several factors: the type of cancer (small cell or not), its stage of evolution, the state of health of the person, and obviously, what the person wishes.
Several medical tests can be used to diagnose and evaluate the severity of the cancer: analysis of sputum or blood samples, biopsy of the suspicious lung mass, as well as images of the lungs obtained by various techniques (radiography, computed tomography, Magnetic resonance imaging). Positron emission tomography and bone scintigraphy complete the assessment and help determine whether there is metastasis elsewhere in the body.
In some cases, the physician and the patient may conclude that the undesirable effects of the treatments outweigh the benefits. It is then possible to opt for palliative care, which will relieve without treating the disease.
|Although in practice it is impossible to take this into account when planning a surgery, it is still interesting to know that the survival rate after surgery seems to be higher in the summer , because of the sunshine. The sun makes the body produce more vitamin D. This vitamin plays a role in the proliferation cycle of cells.|
Small cell cancer
A combination of chemotherapy and radiotherapy is usually offered . This type of cancer responds well to chemotherapy. Treatments help reduce the size of cancer, slow its growth, and prevent metastasis . They usually last a few weeks or months, with stops to allow the body to recover. Nevertheless, relapsesremain unfortunately frequent.
In case of metastases, the radiotherapy will be administered at the place where they are housed.
Surgery is rarely used to treat small cell lung cancer.
Non-small cell cancer
We resort to surgery when the tumor is localized and can be removed safely. The surgeon will remove either a small portion of the lung (peripheral wedge resection), a segment (segmentectomy), an entire lobe (lobectomy), or a whole lung. (We have 2 lungs, the left consists of 2 lobes, and the right of 3.) The operations require only a few days of hospitalization, but the recovery can take several months. If necessary, a rehabilitation programmay help the patient regain range of motion in the chest and arm and full respiratory capacity. With time and breathing exercises, the lung tissue in place expands and the breath improves.
Sometimes, radiation or chemotherapy is combined with surgery to prevent a relapse.
In people who are diagnosed with advanced cancer , it is often too late for the tumor to be removed by surgery. The doctor then offers chemotherapy or radiation to slow the growth of cancer. These treatments can prolong life. However, they cause side effects. For more details, see our Cancer fact sheet (overview).
Experimental drugs can also be used to slow the progression of the tumor.
|Tips to better manage treatment side effects
Read our Cancer fact sheet (overview) for additional approaches that can be used.
Psychological and social support
Seeking support from loved ones, joining a self-help group, attending conferences, or getting support in psychotherapy are all ways to help you get through the difficult times that can occur when the diagnosis is announced and during of the disease. Several programs and services are offered in hospitals and by cancer associations. Ask your medical team.