What is Lung Cancer?
Lung cancer is caused by the excessive
proliferation and without control of certain cells of the lung, causing
initially local problems by occupation of space and compression of surrounding
structures (such as for example, the bronchi). If the growth of the cancer are
not controlled in time, malignant cells move to other organs of the body
through the blood or lymphatic, circulations which is called metastasis. The
extension to other organs prevents, current media, to offer effective
treatments.
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In the Western world, lung cancer is the
most common malignant tumor and causing more deaths. In the United States of
America, a year there are more deaths by lung cancer than the three most common
cancers combined (colon, breast and prostate cancer). In 1995, 600,000 deaths
occurred worldwide as a result of lung cancer. Not many years ago, the most
common cancer in women was breast, but in some Western countries such as the
United States, lung cancer exceeds, both incidence and mortality.
Lung cancer statistics are so poor for two
fundamental reasons:
- High prevalence of smoking. Smoking is the
risk factor most important in the development of lung cancer. It is estimated
that approximately 90% of malignant lung tumors are caused by tobacco. In a
study of patients with cancer of lung carried out in Edinburgh found that only
2% of the patients had never smoked. It is estimated that a smoker has a risk
of developing lung cancer from 10 to 30 times higher than a non-smoker.
- Lack of early detection techniques.
Three most common malignancies following cancer of lung, i.e. the colon, breast
and prostate, there are diagnostic techniques that are effective in early
detection. Thanks to these techniques have been implemented program for the
population at risk in order to decrease the mortality of these tumors. On the
other hand, for lung cancer there no screening program because until a few
years ago there were no techniques that would allow us to detect a tumor at
early stages in which still can be cured by surgical removal.
A study of the Cornell from NYU, which
demonstrated the effectiveness of the thoracic scanner of low doses of
radiation in the detection of early stages lung nodules (tumors), was published
in 1999. As a result of this study, Cornell University has organized an
international multicenter study, which involved the University Clinic of
Navarra, whose aim is to study using thoracic scanner (CT) of low doses of
radiation to the largest possible number of patients.
This collaboration is expected that the
implementation of program of early detection at the national level with the
objective of increasing the percentage of patients diagnosed in stages in which
cancer is still curable by surgery can be recommended in the near future.
Who has lung cancer risk?
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The factor of greatest risk for lung cancer
is smoking. In a study carried out in Edinburgh in 1991, more than 3,000
patients with lung cancer, only 2% had never smoked. In males, tobacco is the
causative agent of lung cancer in 90% of cases, this percentage to decrease in
women to 79%.
The risk that has a smoking chronic a
cancer of lung throughout his life can reach up to 30%, while in non-smokers
this risk is 1%. This risk depends on the number of cigarettes smoked per day,
as well as the number of years that is smoked. Thus, for example, estimated
that the risk of a 35-year-old male of lung cancer before the age of 85 is
approximately 9% If you smoke less than 25 cigarettes a day, or 18% if you
smoke more than 25 cigarettes.
Other risk factors include exposure to
asbestos, polycyclic aromatic hydrocarbons, arsenic and nickel, and suffer
other lung diseases such as lung fibrosis. They have recently gained interest
as potential risk factors exposure to smoke from other smokers (smokers)
tobacco and exposure to radon.
At what age is suffer lung cancer?
The peak of lung cancer incidence occurs in
people over 70 years of age, but people who smoke from an early age, the risk
begins to be apparent from the 40 years. It is rare to develop lung cancer
before this age.
What are the symptoms of lung cancer?
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Only 10% of patients with lung cancer are
diagnosed without having any symptoms. In these cases, diagnosis usually occurs
by chance by becoming a routine chest x-ray or other reasons (insurance,
checks, etc.).
In the majority of cases, the patient goes
to the doctor for symptoms produced, either directly by the primary tumor
(original tumor in the lung), either metastases or Paraneoplastic syndromes
(parallel to the cancer syndromes, usually caused by substances produced by the
tumor itself).
Symptoms caused by the primary tumor
The most common symptom is cough,
persistent, associated or not with expectoration, occurring in a 45-75% of
patients. Sometimes cough is caused by the tumor but by associated with chronic
bronchitis, very common disease in smokers with lung cancer. Coughing is not
specific and occurs frequently in patients with chronic bronchitis. More
specific of a type of lung cancer, bronchoalveolar carcinoma is the
bronchorrhea, defined as persistent and heavy coughing.
Another very common symptom is
breathlessness or shortness of breath sensation. Nor is it a place specific
symptom which occurs frequently in patients very smokers with chronic
obstructive pulmonary disease.
Hemoptysis, or blood in the sputum, is a
worrying sign that should always be studied. However, lung cancer is the cause
of only 20% of all cases of hemoptysis, being the most common cause acute
bronchitis. Up to 50% of patients with lung cancer have hemoptysis on occasion.
Other less common symptoms include: chest
pain, wheezing unilateral (whistles on one side of the chest), weight loss and
loss of voice.
Symptoms caused by extension of the tumor
(metastasis)
The organs where they occur more often the
Metastases of lung cancer are: brain, bones, liver, adrenal glands, and skin.
Metastases in the brain can cause headaches (headache), nausea and vomiting,
focal neurologic deficits (e.g., weakness in an arm or leg), changes in
personality, and seizures. Liver metastasis often produces generalized weakness
(asthenia) and thinning.
How is lung cancer diagnosed?
The study of a patient with suspected lung
cancer has two objectives: first rule out or confirm the presence of cancer,
and then determine its extension or Stadium.
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For the diagnosis of pulmonary tumor begins
to do the following tests that will determine the location of the tumor and the
general State of the patient to undergo the required invasive testing:
radiography, chest CT (scan) of the chest and abdomen, tests of respiratory
function (spirometry) and blood tests. Once located the injury, it is necessary
to obtain a biopsy to determine if the lesion is cancer or not. For this
purpose it resorts to one of four techniques depending on the location in the cancer:
- Bronchoscopy.
- (Through the chest wall) percutaneous
puncture guided by CT.
- Videothorascopy.
- Thoracotomy (incision on the chest wall).
Bronchoscopy is to introduce into the
Airways a thin tube whose end there is a video camera that allows direct
visualization of the bronchi. Because the caliber of the Airways decreases as
it moves the bronchoscope, is technique has the limitation that only allows seeing
the Central bronchi. I.e., if the tumor is on the periphery of the lung,
bronchoscopy is not the preferred technique and intends to do a CT-guided
percutaneous puncture.
With this technique, the radiologists
locate the tumor with a scanner and a thin needle inserted into the lesion
through the chest wall. With the scanner you can check that the needle is in
the tumor and proceeds to aspirate cells that are then studied in the
laboratory. The two techniques described are the least invasive of the four.
However, sometimes it is necessary to resort to surgery to obtain a sample of
the tumor.
The videothorascopy is a surgical technique
that requires general anesthesia and which consists of introducing a rigid tube
into the pleural cavity through the chest wall. Through this tube you can enter
another thinner tube with a video camera at the end. This camera allows you to
locate the injury and obtain the necessary biopsies.
Finally, in a small percentage of patients,
it is not possible to obtain a biopsy for any of the techniques described and
must proceed to surgical removal of the mass by Thoracotomy.
After obtaining biopsy and confirmed the
diagnosis of cancer, it is necessary to determine the extent of the disease to
decide the most appropriate treatment. The study of extension is not equal in
all the centers depending on the available techniques.
The University Clinic of Navarra is
frequently used to the PET (positron emission tomography) Consists of injecting
the patient intravenously radioactive glucose. Malignant tumors are generally
very metabolic so pick up radioactive glucose and can be located using a gamma
camera (radioactivity detector).
Other tests that may be performed, to
determine the presence of metastases or not, include bone scans and magnetic
resonance imaging or CT of the brain.
How is lung cancer?
The treatment of lung cancer is depends on
the stadium in which In early stages, i.e. when the tumor is not spread to
lymph nodes or he has made metastasis to other organs, the treatment of choice
is surgical resection of the lung lobe where the tumor is.
Sometimes it is necessary to draw up a
whole Lung (pneumonectomy), which is usually well tolerated and produces no
significant limitations in terms of the life that the patient may lead in the
future. The prognosis in early stages, when the entire tumor may dry out and
there is no invasion of ganglion, is very good. In these cases you can get the
cure in up to 80% of patients.
Once the tumor has spread the treatment varies
according to the degree of extension. In some cases we offer treatment with
chemotherapy and radiotherapy after resection of the tumor by surgery. Once metastasis
occurs, surgery is not useful, and treatment consists of combinations of
chemotherapy and radiotherapy.(source: cun.es - All about Lung Cancer)
