Lung cancer: Timeline, Causes, Treatment and Prevention

Definition

Cancer is a disease in which cells in the body grow out of control. When cancer starts in the lungs, it is called lung cancer.

Lung cancer

Lung cancer begins in the lungs and may spread to lymph nodes or other organs in the body, such as the brain. Cancer from other organs also may spread to the lungs. When cancer cells spread from one organ to another, they are called metastases.

Timeline

Cavemen with cancer: 200 possible cancer sightings made by archaeologists, dating to prehistoric times

1500 B.C.: world’s oldest documented cases of cancer. 8 recorded on papyrus.

Fact: Egyptians believed cancer was caused by the Gods.

Fact: Egyptians treated by cauterization using a hot instrument called “The fire drill.” [Sounds gruesome, doesn’t it?]

Hippocrates (460-370 B.C.): Used the word carcinos and carcinoma for tumors. Called cancer Karkinos.

The Greeks believed: cancer caused by excess of black bile in the body.

1761: Lung cancer identified as a distinct disease.

1810: Various characteristics of lung cancer identified.

1876-1938: 60 to 80% of all miners died from the disease. Mines were known as “death pits,” where workers got sick.

1878: lung cancer still considered rare. Malignant lung tumors are only 1% of all cancers.

By 1918, the percentage rises to 10%

And by 1927: more than 14%.

1929: German physician Fritz Lickint first recognized the potential connection between smoking and lung cancer. This discovery led to a nationwide anti-tobacco movement in Nazi Germany.

1940: Lung cancer becomes second most frequent cause of cancer death, stomach cancer being #1

1954: An American Cancer Society links smoking and lung cancer.

1964: The U.S. Surgeon General report: says smoking cigarettes is cause of lung cancer and laryngeal cancer in men and a probable cause of lung cancer in women.

By 2013: Lung cancer accounts for more deaths than any other cancer: 159,480 deaths, that’s 27 %

Epidemiology

An estimated 1.35 million people were diagnosed with lung cancer worldwide during 2002 (12% of all invasive cancers), an increase of about 110,000 compared with the number of lung cancers diagnosed in 2000.24 About 71% (or about 960,000) of these lung cancer diagnoses were among males, with age-standardized rates (using the World Health Organization World Standard population)25 of 40 and 13 new cases per 100,000 population for males and females respectively.

Globally, lung cancer has been the most common cancer diagnosed each year since 1985.  Lung cancer had a higher incidence among males worldwide than any other cancer, followed by prostate cancer (more common in developed countries) and stomach cancer (particularly in developing countries). Among females, lung cancer was the fourth most diagnosed cancer, behind breast cancer, cervical cancer (mostly in developing countries), and colorectal cancer.

For both sexes, the estimated number of lung cancer cases diagnosed in more developed countries during 2002 was similar to that in less developed countries. However, after allowing for differences in population size and age structures, lung cancer incidence rates were around twice as high in more developed countries (61/100,000 among males and 19/100,000 among females) compared with less developed countries (29/100,000 among males and 10/100,000 among females).

Sex-specific incidence rates varied substantially between countries. For males, estimated lung cancer incidence rates ranged from 104/100,000 in Hungary to less than 5/100,000 in many African countries (such as Kenya). The highest estimated rate for females was in the United States (40/100,000 population) compared with a rate of between 2 to 3/100,000 in a range of less developed countries including India, Algeria, Kenya, and Iran

Types

Doctors divide lung cancer into two major types based on the appearance of lung cancer cells under the microscope. Your doctor makes treatment decisions based on which major type of lung cancer you have. The two general types of lung cancer include:

Small cell lung cancer. Small cell lung cancer occurs almost exclusively in heavy smokers and is less common than non-small cell lung cancer.

Non-small cell lung cancer. Non-small cell lung cancer is an umbrella term for several types of lung cancers that behave in a similar way. Non-small cell lung cancers include squamous cell carcinoma, adenocarcinoma and large cell carcinoma.

Risk factors

A number of factors may increase your risk of lung cancer. Some risk factors can be controlled, for instance, by quitting smoking. And other factors can’t be controlled, such as your family history.

Risk factors for lung cancer include:

Smoking. Your risk of lung cancer increases with the number of cigarettes you smoke each day and the number of years you have smoked. Quitting at any age can significantly lower your risk of developing lung cancer.

Exposure to secondhand smoke. Even if you don’t smoke, your risk of lung cancer increases if you’re exposed to secondhand smoke.

Exposure to radon gas. Radon is produced by the natural breakdown of uranium in soil, rock and water that eventually becomes part of the air you breathe. Unsafe levels of radon can accumulate in any building, including homes.

Radon testing kits, which can be purchased at home improvement stores, can determine whether levels are safe. If unsafe levels are discovered, remedies are available.

Exposure to asbestos and other carcinogens. Workplace exposure to asbestos and other substances known to cause cancer  such as arsenic, chromium and nickel  also can increase your risk of developing lung cancer, especially if you’re a smoker.

Family history of lung cancer. People with a parent, sibling or child with lung cancer have an increased risk of the disease.

Causes

Lung cancer is caused by a mutation in your DNA. When cells reproduce, they divide and replicate, forming identical cells. In this way, your body is constantly renewing itself. Inhaling harmful, cancer-causing substances, or carcinogens, damages the cells that line your lungs. Examples of these carcinogens include:

  • Cigarette smoke
  • Asbestos
  • Radon

At first, your body may be able to repair itself. With repeated exposure, your cells become increasingly damaged. Over time, the cells begin to act abnormally and grow uncontrollably. This is how cancer can develop.

Several precancerous changes have to occur before cancer actually manifests. The buildup of extra cells causes tumors, which are either benign or malignant. Malignant cancerous lung tumors can be life-threatening. They can spread and even return after they have been removed.

Personal history and lifestyle choices

Genetics

Current research suggests that if a member of your immediate family has had lung cancer, you may have a slightly higher risk of developing the disease. Immediate family includes the following relations:

  • mother
  • father
  • sibling
  • aunt
  • uncle
  • grandparent

This elevated risk is true even if you don’t smoke. It’s unclear whether genetics causes lung cancer or merely increase your susceptibility to it.

Age

According to the American Cancer Society, lung cancer mostly occurs in older adults. Two out of three people diagnosed with lung cancer are 65 or older. The average age at the time of diagnosis is about 70. The older you are, the longer you have been exposed to harmful chemicals. This longer exposure increases your risk for cancer.

Past lung diseases

Past lung diseases can cause inflammation and scarring in the lungs. Examples of these diseases include tuberculosis, chronic obstructive pulmonary disease (COPD), chronic bronchitis, and emphysema. You may be at a greater risk of developing lung cancer if you have a history of chronic diseases that affect the lungs.

Radiation therapy to the chest

Radiation therapy used to treat other cancers like non-Hodgkin’s lymphoma and breast cancer may increase your risk of lung cancer. This risk is higher if you smoke.

Secondhand smoke

Even if you don’t smoke, being exposed to secondhand smoke can increase your risk of lung cancer. This exposure can occur at any place you spend time, such as:

  • Home
  • Work
  • Restaurants
  • Bars

According to the CDC, each year about

Symptoms

Find out about possible symptoms of lung cancer and when to see your doctor.

These symptoms could be due to lung cancer but can also be caused by other medical conditions.

A cough that won’t go away

You might have a cough most of the time. It might be worse at different times of the day.

A change in a cough you have had for a long time

Your cough might:

  • Be more painful
  • Have a different sound
  • Bring up coloured mucus or phlegm

Being short of breath

You might get out of breath doing the things you used to do without a problem.

Coughing up blood

This might be small amounts of blood. You might be coughing up rust coloured phlegm (sputum). Or your sputum might have flecks of red in it.

It is more unusual to cough up larger amounts of blood. But see your doctor straight away if this happens.

An ache or pain in the chest or shoulder

You might have pain in your chest or shoulder. It could be a dull ache or a sharper pain.

Loss of appetite

You might have lost your appetite or may not feel like eating foods that you normally like.

Losing weight

You might lose a lot of weight quickly when you are not dieting.

Feeling very tired (fatigue)

You might feel very tired a lot of the time.

Ongoing chest infections

You might have chest infections most of the time. Or you might have a chest infection that doesn’t get better with treatment.

Hormone related symptoms

Some types of lung cancer cells produce hormones that go into the bloodstream. These hormones can cause symptoms that don’t seem related to the lung cancer. Doctors call them paraneoplastic syndrome.

These hormone symptoms might include:

  • Pins and needles or numbness in the fingers or toes
  • Muscle weakness
  • Drowsiness, weakness, dizziness and confusion
  • Breast swelling in men
  • Blood clots

Diagnosis and test

Several organizations recommend people with an increased risk of lung cancer consider annual computerized tomography (CT) scans to look for lung cancer. If you’re 55 or older and smoke or used to smoke, talk with your doctor about the benefits and risks of lung cancer screening.

Some studies show lung cancer screening saves lives by finding cancer earlier, when it may be treated more successfully. But other studies find that lung cancer screening often reveals more benign conditions that may require invasive testing and expose people to unnecessary risks and worry.

Tests to diagnose lung cancer

If there’s reason to think that you may have lung cancer, your doctor can order a number of tests to look for cancerous cells and to rule out other conditions. In order to diagnose lung cancer, your doctor may recommend:

  • Imaging tests.An X-ray image of your lungs may reveal an abnormal mass or nodule. A CT scan can reveal small lesions in your lungs that might not be detected on an X-ray.
  • Sputum cytology.If you have a cough and are producing sputum, looking at the sputum under the microscope can sometimes reveal the presence of lung cancer cells.
  • Tissue sample (biopsy).A sample of abnormal cells may be removed in a procedure called a biopsy.

Your doctor can perform a biopsy in a number of ways, including bronchoscopy, in which your doctor examines abnormal areas of your lungs using a lighted tube that’s passed down your throat and into your lungs; mediastinoscopy, in which an incision is made at the base of your neck and surgical tools are inserted behind your breastbone to take tissue samples from lymph nodes; and needle biopsy, in which your doctor uses X-ray or CT images to guide a needle through your chest wall and into the lung tissue to collect suspicious cells.

A biopsy sample may also be taken from lymph nodes or other areas where cancer has spread, such as your liver.

Lung cancer staging

Once your lung cancer has been diagnosed, your doctor will work to determine the extent (stage) of your cancer. Your cancer’s stage helps you and your doctor decide what treatment is most appropriate.

Staging tests may include imaging procedures that allow your doctor to look for evidence that cancer has spread beyond your lungs. These tests include CT scans, magnetic resonance imaging (MRI), positron emission tomography (PET) and bone scans. Not every test is appropriate for every person, so talk with your doctor about which procedures are right for you.

Stages of lung cancer

Stage I. Cancer is limited to the lung and hasn’t spread to the lymph nodes. The tumor is generally smaller than 2 inches (5 centimetres) across.

Stage II. The tumor at this stage may have grown larger than 2 inches, or it may be a smaller tumor that involves nearby structures, such as the chest wall, the diaphragm or the lining around the lungs (pleura). Cancer may also have spread to the nearby lymph nodes.

Stage III. The tumor at this stage may have grown very large and invaded other organs near the lungs. Or this stage may indicate a smaller tumor accompanied by cancer cells in lymph nodes farther away from the lungs.

Stage IV. Cancer has spread beyond the affected lung to the other lung or to distant areas of the body.

Small cell lung cancer is sometimes described as being limited or extensive. Limited indicates cancer is limited to one lung. Extensive indicates cancer has spread beyond the one lung.

Treatment and medications

About one-third of lung cancer patients are diagnosed with localized disease that may be treated by either surgical resection or, if the patient is not a candidate for full surgical resection, with definitive radiotherapy. Another third of patients have disease that has already spread to the lymph nodes. In these cases, radiation therapy along with chemotherapy and occasionally surgery is used. The last third of patients may have tumors that have already spread to other parts of the body via the blood stream and are typically treated with chemotherapy and sometimes with radiation therapy for the relief of symptoms.

Surgery with removal of the entire lobe in which the tumor is located, is the primary treatment for patients with early-stage cancer who are in good general health. The goal of surgery is to totally eliminate all the tumor cells and thereby provide a cure. Unfortunately, lung cancers tend to develop in smokers more than 50 years of age, who very often have other lung disease or serious medical conditions that magnify the risk of surgery. The location and size of a lung tumor dictate how extensive the operation must be. Open thoracotomy or less invasive video-assisted thoracic surgery, using smaller incisions, may be recommended for appropriately selected patients.

Lobectomy- removal of an entire lobe of the lung  is an accepted procedure for removing lung cancer when the lungs are functioning well. The mortality risk is 3 percent to 4 percent, and tends to be highest in older patients. If lung function prohibits lobectomy, a small cancer confined to a limited area can be removed with a small portion of surrounding lung tissue. This is called a sublobar resection, and may be either a wedge resection or a segmentectomy. There is a possible higher risk of recurrence with more limited surgery than a lobectomy. Sublobar resections cause less loss of lung function, as a smaller portion of lung is removed, and carries an operative mortality risk of 1.4 percent. If the entire lung must be taken out by pneumonectomy, the expected mortality rate is 5 percent to 8 percent. The oldest patients are at highest risk and recurrent cancer is very common.

In a majority of cases, either the patient is not fit for surgery or it is not possible to remove the entire tumor because of its size or location.

Radiation therapy, or radiotherapy, delivers high-energy x-rays that can destroy rapidly dividing cancer cells. It has many uses in lung cancer:

  • As primary treatment
  • Before surgery to shrink the tumor
  • After surgery to eliminate any cancer cells that remain in the treated area

To treat lung cancer that has spread to the brain or other areas of the body

In brachytherapy, radiation is delivered directly to the site of disease. This is usually achieved either through a surgical procedure where after resection of the primary tumor radioactive seeds are sutured to the edge of the surgical resection. Also, in the setting of an obstructive tumor within an airway, radiation is delivered to the site of obstruction through plastic tube that is temporarily inserted into the airway. This may help to relieve severe symptoms but does not cure the cancer.

Chemotherapy involves drugs that are toxic to cancer cells. The drugs are usually given by direct injection into a vein or through a catheter placed in a large vein. Often given after surgery to sterilize microscopic disease, chemotherapy also may slow tumor growth and relieve symptoms in patients who cannot have surgery. Newer biologic agents, which may have fewer side effects than traditional chemotherapy and in some instances may be just as effective, are being used. This treatment is used in all stages of lung cancer and can prolong life even in elderly persons as long as they are in good general health. Some chemotherapy drugs increase damage done to tumors by the radiation treatment of cancer cells. Others keep the tumor cells at a stage where they are most susceptible to radiation treatment, or impair the ability of cancer cells to repair themselves after a course of radiation therapy. Evidence is mounting that a combination of these drugs integrated with radiotherapy is more effective than radiotherapy alone, but there is a substantial risk of serious side effects. Chemotherapy may cause significant side effects, such as nausea with vomiting and damage to the white blood cells that are needed to combat infection, but there now are ways to counter and treat most of these effects.

Prevention

There’s no sure way to prevent lung cancer, but you can reduce your risk if you:

Don’t smoke: If you’ve never smoked, don’t start. Talk to your children about not smoking so that they can understand how to avoid this major risk factor for lung cancer. Begin conversations about the dangers of smoking with your children early so that they know how to react to peer pressure.

Stop smoking: Stop smoking now. Quitting reduces your risk of lung cancer, even if you’ve smoked for years. Talk to your doctor about strategies and stop-smoking aids that can help you quit. Options include nicotine replacement products, medications and support groups.

Avoid secondhand smoke: If you live or work with a smoker, urge him or her to quit. At the very least, ask him or her to smoke outside. Avoid areas where people smoke, such as bars and restaurants, and seek out smoke-free options.

Test your home for radon: Have the radon levels in your home checked, especially if you live in an area where radon is known to be a problem. High radon levels can be remedied to make your home safer. For information on radon testing, contact your local department of public health or a local chapter of the American Lung Association.

Avoid carcinogens at work: Take precautions to protect yourself from exposure to toxic chemicals at work. Follow your employer’s precautions. For instance, if you’re given a face mask for protection, always wear it. Ask your doctor what more you can do to protect yourself at work. Your risk of lung damage from workplace carcinogens increases if you smoke.

Eat a diet full of fruits and vegetables: Choose a healthy diet with a variety of fruits and vegetables. Food sources of vitamins and nutrients are best. Avoid taking large doses of vitamins in pill form, as they may be harmful. For instance, researchers hoping to reduce the risk of lung cancer in heavy smokers gave them beta carotene supplements. Results showed the supplements actually increased the risk of cancer in smokers.

Exercise most days of the week: If you don’t exercise regularly, start out slowly. Try to exercise most days of the week.

About DiseasesDic

Check Also

Leukocytosis – Causes, Symptoms and Treatment

Definition Leucocytosis is the condition in which the body has a higher level (more than …

Leave a Reply

Your email address will not be published. Required fields are marked *