Diagnosing lung cancer

Lung cancer is one of the highest prevailing diseases in our world today. Like any other cancer, it occurs due to the abnormal growth of cancerous cells originating either from the lung tissue itself or elsewhere in the body and metastasizing to the lung. Most of the cases are diagnosed at a later stage where the cancer has spread and increased in severity. However, proper diagnosis and treatment can go a long way.

A thorough medical history of the patient is always the first step towards establishing a diagnosis. It points the physician towards the right direction; a correct diagnosis.

Various tests are performed in patients in order to diagnose lung cancer. The information from these tests enables the physician to determine the type and stage of the cancer and the best way to treat it. The tests include physical examination, chest examination, chest X-ray, CT scan, positron emission tomography (PET) scan, MRI, sputum cytology, bronchoscopy, biopsy and spiral CT scan.

Physical examination is important for detecting any external signs of cancer such as swollen lymph nodes in the neck or nearby area that can point towards a possible diagnosis.

Examining the chest and listening to the lungs with a stethoscope provides information about abnormal breathing sounds or patterns that may be characteristic to the disease.

Computed tomography, also known as CT or CAT scan, is a sophisticated instrument that uses a computer to create a two-dimensional scan from a series of X-ray images. The newest version of the CT is called a helical or spiral scan. CT scans show much more detail than x-rays and the new helical or spiral scans are even more sensitive than regular CT scans. Extensive details of cancer affected tissues, if present, can be received through this scan. MRI is similar to a CT scan except is uses a magnetic field instead of X-rays to create an image. The spiral (or helical) CT scan can image the lungs in a single breath hold and are more sensitive than the normal CT scans.

Chest X-rays are "flat" pictures of the lungs, which help in identifying any abnormal growths. The variation in the resulting picture depends on the variable density of the tissues that the radiation is passing through.

Recently published results from a large clinical trial showed that annual screening with chest x-ray does not reduce mortality. Newer tests, such as low-dose spiral CT scans and molecular markers in sputum, have produced promising results in detecting lung cancers at earlier, more operable stages in high-risk patients. Results from the National Lung Screening Trial, showed 20% fewer lung cancer deaths among current and former heavy smokers who were screened with spiral CT compared to standard chest x-ray.

Positron Emission Tomography (PET) is a scan that makes a diagnosis using a cancer's rapidly dividing cells. Radiologists administer a radioactive substance to the patient that will be absorbed more by the cancer than by normal tissues, due to the cancer cells' increased need for energy. The PET scan records the areas where the radioactivity is focused.

Sputum cytology examines phlegm coughed out by the patient, under a microscope to check for abnormal or cancerous cells. More information on treatments can be found on healthcarevilla.com.

Bronchoscopy is viewing of the lungs through a lighted, flexible tube (bronchoscope) that is passed through the nose and throat into the main airway of the lungs. The tube, which has a light on the end, allows the doctor to see inside of the lung. If abnormal areas or tumors are seen, cell tissue samples can be obtained through special tools located at the end of the bronchoscope for evaluation under a microscope. These samples are also called biopsy samples. A biopsy sample can be obtained in other different ways, depending on the location of the tumor. For example, by inserting a needle through the chest into the lung and removing part of the tissue for testing, by removal and examination of an enlarged lymph node in the neck or by a small surgery on the lung.

An overview of lung cancer

Lung cancer is the uncontrolled growth of abnormal cells taking place in one or both lungs. As tumors become larger and more numerous, they undermine the lung’s ability to provide the bloodstream with oxygen.

The statistics from the GLOBOCAN 2008 cancer fact sheet state that lung cancer has been the most common cancer in the world for several decades, and by 2008, there were an estimated 1.61 million new cases, representing 12.7% of all new cancers. It was also the most common cause of death from cancer, with 1.38 million deaths. Majority of the cases now occur in the developing countries. It is still the most common cancer in men worldwide (1.1 million cases), with high rates in Central-Eastern and Southern Europe, Northern America and Eastern Asia. In females, incidence rates are generally lower, however, worldwide, it is now the fourth most frequent cancer of women (516 000 cases) and the second most common cause of death from cancer (427 000 deaths). The highest incidence rate is observed in Northern America and the lowest in Middle Africa. Because of its high fatality (the ratio of mortality to incidence is 0.86) and the lack of variability in survival in developed and developing countries, the highest and lowest mortality rates are estimated in the same regions, both in men and women.

According to the American Cancer Society, this cancer makes up 14% of all newly diagnosed cancers in the USA today. Annually, more patients die from it alone than prostate, breast and colon cancers put together (in the USA). An American man’s lifetime risk of developing lung cancer is 1 in 13; for a woman the risk is 1 in 16. These risk figures are for smokers, ex-smokers and non-smokers. The risk for a regular smoker is considerably higher.

Cigarette smoking is by far the most important risk factor for lung cancer. Exposure to radon gas released from soil and building materials is estimated to be the second leading cause of lung cancer in Europe and North America. Other risk factors include occupational or environmental exposure to smoke, asbestos, certain metals (chromium, cadmium, arsenic), organic chemicals, radiation, air pollution, and paint. Risk is also increased among patients of tuberculosis. Genetic susceptibility also contributes to the development, especially in people who develop the disease at a younger age.

Most patients are over the age of 60 years when they are diagnosed. It takes several years to reach a level where symptoms are felt and the sufferer decides to seek medical help. Symptoms may take year to appear and are quite varied and depend on its location, spread, and size of tumor. These include:

·         persistent or intense coughing,

·         pain in the chest shoulder, or back from coughing,

·         changes in color of the sputum,

·         difficulty breathing and swallowing,

·         hoarseness,

·         stridor,

·         chronic bronchitis or pneumonia,

·         hemoptysis

·         swollen/enlarged lymph nodes

·         fever,

·         fatigue,

·         unexplained weight loss,

·         pain in joints or bones,

·         swelling in the neck or face,

·         general weakness,

·         bleeding and blood clots.  

In the case of metastasis, the symptoms depend upon the site of spread.

Early screening can help detect cancer development at an early stage and help reduce mortality. Sputum cytology, chest x-rays and CT scans are mainly used for screening. New technologies are emerging that aim for early detection. More information on screening and diagnostic tests can be found on healthcarevilla.com.

Lung cancer is classified as small cell or non-small cell for the purposes of treatment which includes surgery, radiation therapy, chemotherapy, and targeted therapies. For most cases, surgery is usually the treatment of choice, and survival for most of these patients is improved by giving chemotherapy after surgery. Because the disease has usually spread at the time of diagnosis, radiation therapy and chemotherapy are often used, sometimes in combination with surgery. Prognosis is generally poor. Of all patients, 15% survive for five years after diagnosis.