7
Lung Cancer
IN THIS CHAPTER YOU’LL DISCOVER
→ Screening/Specific Diagnostic Tests
→ What Happens if Lung Cancer Spreads
JENNY WHITE WAS CLEANING her bathroom when she unwittingly breathed in a noxious combination of bleach and bathroom cleaner that sent her into a coughing fit and eventually to see her doctor. He sent her for a chest X-ray, which showed an unrelated nodule on her lung. Her doctor monitored it and, since it was growing, she had no choice but to undergo surgery so a biopsy could be taken.
“My doctor had told me before the surgery that if I saw one chest tube in me when I awakened, it meant that the nodule was harmless, but if I saw two, it was cancer. When I awoke, I saw the two tubes,” she recalls. Stunned, Jenny, a lifelong smoker, realized she was dealing with lung cancer.
What Is Lung Cancer?
Also known as pulmonary carcinoma, lung cancer forms just like other cancers — abnormal cells begin to grow and divide at an uncontrollable rate. In the case of the lungs, the two sponge-like organs that make up the main component of the respiratory system, cancerous cells form a tumor, lesion, or nodule. As cells continue to multiply, nearby tissues and organs are also threatened by the disease.
When we breathe, our lungs drink in oxygen, and when we exhale, they expel carbon dioxide, the waste product our body’s cells produce. This process is vital for life. As the cancer grows and spreads, it becomes impossible for the lungs to serve this very important, life-giving function.
Statistics
There are about 250,000 new cases of lung cancer each year, roughly affecting men and women equally, and resulting in an estimated 160,000 deaths each year, which accounts for about 27 percent of all cancer deaths.
Lung cancer is by far the leading cause of cancer death among both men and women. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined. Traditionally thought of as a man’s disease, it is now an equal opportunity killer. This is because lung cancer may take up to 20 years to develop, and women historically began smoking heavily about two decades or so after men.
“The incidence of lung cancer has decreased slightly in men because a lot of men who used to smoke quit, but not in women because they started smoking later,” says Bruno Bastos, MD, an oncologist who specializes in lung cancer at Cleveland Clinic Florida.
Lung cancer mainly occurs in older people. About two-thirds of those diagnosed with lung cancer are 65 or older; fewer than two percent of all cases are found in people younger than 45. The average age at the time of diagnosis is about 70.
Overall, the chance that a man will develop lung cancer in his lifetime is about one in 13; for a woman, the risk is about one in 16. (These numbers include both smokers and non-smokers.)
Outcome and Survival Rates
There are about 400,000 lung cancer survivors living in the United States today. “Although the survival rate for lung cancer has stayed relatively unchanged, it is expected to climb thanks to new treatments. In the meantime, the quality of life for lung cancer patients is improving,” Dr. Bastos says.
If lung cancer is caught at its earliest stage (Stage 0), the survival rate is 60 to 80 percent. If it is caught at Stage I or Stage II, the survival rate is 40 to 50 percent. For people with large tumors, but no evidence of spread, this may be higher. The survival rate for Stage III lung cancer is about 23 percent, and if the cancer reaches Stage IV, this figure drops to 10 percent.
It is important to recognize, though, that lung cancer can be diagnosed at any of the stages. In addition, the type, size, and location of the cancer can make a big difference. Typically, women survive with lung cancer longer than do men. Whether or not other lung diseases are present also makes a difference.
SMOKING AND LUNG CANCER
It will come as no shock that the chief cause of lung cancer is cigarette smoking. Although people who are non-smokers can get lung cancer, well over 80 percent of cases are due to smoking. People who smoke cigars, pipes, and even marijuana are also at higher risk, although not as high as those who smoke cigarettes.
Cigarette smoke contains thousands of chemical compounds, many of which are carcinogenic (cancer-causing). When we smoke, our lungs retain 70 to 90 percent of these compounds. There is also is evidence that these chemicals damage DNA, the body’s genetic code, paving the way for cancer to develop.
How much do you need to smoke to develop cancer? Experts discuss this question in terms of “pack-years.” They place at highest risk the smoker who has accumulated 30 pack-years. This amount can be accrued in different ways: a person can smoke a pack a day for 30 years, two packs for 15 years, three packs for 10 years, and so on.
But don’t confuse these distinctions with real life. In real life, there’s no magic number; susceptibility to cancer varies widely from person to person. Some people can smoke their entire, long lives and remain cancer-free; others may never have smoked even one cigarette and develop the disease.
Not all smokers get lung cancer, which is an indication that genetics is involved. People with relatives who developed lung cancer are at higher risk than others. In addition, chronic obstructive pulmonary disease, or COPD (the umbrella label for a group of diseases that include emphysema and chronic bronchitis), increases lung cancer risk.
“Although smoking is by far the greatest risk factor, some non-smokers do develop lung cancer. This is true of both men and women non-smokers, but there appears to be an albeit small, but growing group comprised of female lung cancer victims who have developed the disease for, thus far, no explicable reason,” says Dr. Bastos. Indeed, statistics show that one in five women who develop lung cancer are non-smokers.
Although cigarette smoke accounts for the vast majority of lung cancer cases, a host of environmental pollutants can play a role. Chief among these is asbestos, a carcinogenic material used mainly for things like insulation and brake linings. Over the years, the awareness of the danger posed by asbestos has grown and we’ve limited our exposure. Asbestos is still found in some places, although removing it — causing fibers to become airborne — sometimes poses more of a danger than leaving it in place. Lung cancer from exposure to asbestos can take decades to develop.
Radon is another lung cancer risk factor. This radioactive gas, which is given off by uranium, thorium, certain rocks, and soil, surrounds us. In open areas, radon diffuses into the air, so low-level, outdoor exposure is not harmful, but it can seep into buildings, such as homes, as well. Large concentrations of radon in poorly ventilated conditions (like underground mines), pose an extremely detrimental threat.
Long-term exposure to air pollution also heightens risk because it is filled with some of the same toxic gases, such as nitrogen oxide and carbon monoxide, found in cigarette smoke.
In addition, excessive alcohol use (more than three drinks a day) is associated with higher lung cancer risk. Since many people are inclined to smoke while imbibing alcoholic drinks, this would obviously raise the risk more.
Some diseases — or the treatment for them — will hike lung cancer risk as well. For example, radiation to treat breast cancer or blood cancers (like leukemia and non-Hodgkin’s lymphoma), raises the risk, even decades later.
Types of Lung Cancer
There are many different forms of pulmonary carcinoma, but the more common ones are broadly divided into two basic categories: small cell lung cancer and non-small cell lung cancer.
SMALL CELL CARCINOMA
This is the more aggressive, but less common type of lung cancer. Its small, oat-like cells (which is why it’s also known as oat-cell cancer) occur in the tissue of the lungs and often it is not diagnosed until it has spread elsewhere in the body. It is usually found in smokers and former smokers. This type of carcinoma accounts for 15 to 20 percent of all cases.
NON-SMALL CELL LUNG CANCER (NSCLC)
This type of lung cancer grows more slowly than small cell carcinoma. Non-small cell is the largest category of lung cancer and accounts for some 80 percent of lung cancer cases.
Although there are other, rarer types of non-small cell lung cancers, this form of pulmonary carcinoma is divided into major three types:
- • Squamous cell: Also called epidermoid, this type of cancer begins in the lung’s central areas or in one of the two major air passages and grows slowly. It occurs more commonly in men. Epidermoid lung cancers are almost always caused by smoking.
- • Adenocarcinoma: This type often develops along the outer edges of the lung and under the membranes of the large air passages of the lungs. It is the most common type of lung cancer, and slightly more predominant in women.
- • Large cell lung cancer: Large, abnormal cells characterize this type of lung cancer, which usually begins in the smaller breathing tubes, but can appear anywhere in the lungs.
Stages of Lung Cancer
STAGE 0, OR CARCINOMA IN SITU
This describes abnormal cells that have not grown beyond the lining of the airways. Again, if the cancer is described as being in situ, this means that it is non-invasive, and, at this early stage, is not yet capable of spreading to other regions. As the cancer grows, however, it may spread. Lung cancer that is caught this early is usually picked up accidentally, possibly due to a person getting a chest X-ray or CT scan for some other reason.
STAGE I
This stage involves a situation in which the cancer is confined to the lung and hasn’t spread to the lymph nodes. The tumor is generally three centimeters or smaller.
STAGE II
This describes a tumor that is not larger than seven centimeters and may have spread to areas nearby, such as the chest wall, the diaphragm, the lining around the lungs or heart, or the area not less than two centimeters below where the trachea meets the bronchus (the large airway that bridges the trachea and lung). The cancer may also have spread to the nearby lymph nodes. The portion of the lung where the trachea meets the bronchus may be collapsed or inflamed. One lobe of the lung may contain one or more separate tumors.
STAGE III
This stage is marked by the cancer’s invasion of other organs near the lungs, like the heart and its major blood vessels, the esophagus, and larynx (voice box). The tumor(s) may be large, but even in the event of smaller tumors, cancer cells may be present in the lymph nodes farther away from the lungs. Part of the lung may have collapsed or become inflamed.
STAGE IV
The cancer has spread beyond the affected lung to the other lung and to distant areas of the body, such as the brain, liver, kidneys, or bones.
Signs and Symptoms of Lung Cancer
Lung cancer is so dangerous because it usually causes no early symptoms, which provides it with the opportunity to spread before it is diagnosed. If lung cancer develops in the windpipe, it does cause a cough, but too often that is brushed off as “smoker’s cough.” It is important to bring any of these symptoms to a doctor’s attention immediately:
- • Persistent, deep, wheezing cough
- • Increased sputum (mucus) which may be streaked with blood
- • Chronic chest pain
- • Belabored breathing
- • Recurring pneumonia or bronchitis
- • Difficulty swallowing
- • Hoarseness
- • Arm and shoulder pain (this can occur in one type of rare lung cancer)
- • Fatigue
Lung Cancer Screening
For the past several years, researchers have been testing low-dose, spiral CAT screening to determine whether the method could be used for early detection of lung cancer. Finally, in 2013, enough evidence had been collected proving that, for high-risk individuals, the benefits of this type of screening greatly outweigh the dangers (complications from low-dose radiation exposure). The US Preventive Services Task Force now recommends that current smokers between the ages of 55 and 80 or those who have quit within the past 15 years undergo screening. The task force defines high-risk as those who have 30 pack-years or more.
Specific Diagnostic Tests
PHYSICAL EXAMINATION
The doctor will take a detailed inventory of the patient’s symptoms, medical history, and smoking history, and will also perform a general examination.
SPUTUM CYTOLOGY
A sample of mucus will be taken and examined under a microscope to look for signs of cancer. The doctor will collect a sample by having the patient cough (often induced by having the patient breathe a saline mist) or via a bronchoscopy — a procedure that enables the doctor to insert a scope in order to view the patient’s airways, at which time a sample may be taken as well.
CHEST X-RAY
Not suitable for early lung cancer screening, chest X-rays are able to pick up more advanced tumors. Smaller tumors will not show up on chest X-rays, necessitating a CT (or CAT) scan or other imaging test.
CT SCAN (ALSO CALLED A CAT, SPIRAL CT, OR HELICAL SCAN)
This more sophisticated imaging test can detect smaller tumors, making it a far more reliable tool than a chest X-ray for detecting lung cancer in its earlier stages. The CT scan is the best method available for lung cancer screening; however, since it exposes the recipient to low doses of radiation, the test is recommended only to those who are considered high-risk for the disease (current or former smokers between 55 and 74 with a 30 pack-year or more history).
OTHER IMAGING TESTS
These include magnetic resonance imaging (MRI) and positron emission tomography (PET scan), which are done both to detect tumors and to see if they have spread.
BIOPSY
In order to confirm the diagnosis of lung cancer as well as determine the cell type to correctly recommend treatment, this test must be performed. A biopsy involves removing a bit of tissue from the lungs and examining it under a microscope. A biopsy is also performed to determine the stage of the cancer.
BRONCHOSCOPY
The doctor uses a thin viewing instrument, the bronchoscope, to view the airway, lungs, or lymph nodes of the chest to check for signs of cancer. A bronchoscopy can also be done to remove tissue samples for biopsy.
MEDIASTINOSCOPY
This is a surgical procedure that calls for the making of a small cut in the neck or on the left side of the chest. Then a thin scope called a mediastinoscope is inserted through the opening in order to explore the mediastinum (the space between the lungs). This is another way to perform a biopsy.
PULMONARY FUNCTION TEST
An evaluation of lung capacity is measured, either by means of breathing tests or by having the patient inhale nitrogen or helium for a specific period of time, after which the amount of gas in the lungs is measured to determine lung volume.
THORACENTESIS
The doctor will insert a needle between the lung and the chest wall, collecting fluid to be checked for cancer cells.
THORACOSCOPY
An endoscope (a thin, tubelike instrument outfitted with a camera) is placed into an incision made in the skin to examine the pleura (membrane lining chest cavity and the outside of each lung), lungs, and mediastinum, and also remove tissue for examination.
BLOOD TESTS AND TUMOR MARKERS
Lung cancer can secrete proteins and hormones into the bloodstream. These tumor markers can furnish important information as to the diagnosis, type of tumor, and evaluating what types of treatments might be most effective.
Such molecular testing is not being done often enough. In fact, a 2015 study showed that 25 percent of patients who might have benefited from such testing missed out. So a consortium of organizations has come out with guidelines specifying that all patients with advanced lung adenocarcinoma should be tested for abnormalities in two genes: EGFR and ALK. Patients with the EGFR abnormality can be treated with Tarceva (erlotinib), and those with ALK can receive Xalkori (crizotinib). In addition, clinical testing is underway for new drugs targeting these genetic abnormalities.
Treatments
There are four types of treatments for lung cancer: surgery, chemotherapy, radiation therapy, and targeted therapy. The treatment depends on the type of cancer found and whether it has spread to the lymph nodes and/or to other parts of the body.
SURGERY
Small cell lung cancer is very aggressive, fast-growing, and very often has extensively spread by the time it is discovered. Therefore, surgery is only curative in a very small number of patients (about five percent). However, when surgery is done on these patients in combination with chemotherapy and radiation, it can result in a 35 to 40 percent cure rate.
Non-small cell lung cancer grows more slowly, so the chance of discovering it while the tumor is still operable is greater.
CHEMOTHERAPY
Chemical treatment may be administered before surgery to try and shrink the tumor, after surgery to keep the cancer from returning, or as the main type of treatment in lung cancer cases that are too far advanced for surgery.
RADIATION
Radiation can be used as the main treatment for tumors that cannot be surgically removed. Radiation can also be done to shrink the tumor before surgery or afterwards to kill any remaining cancer cells and prevent recurrence.
There are several different types of radiation that can be used for lung cancer, including high-dose brachytherapy (also called high-dose remote radiation), which is used on people with lung cancers located in the major bronchi, or breathing passages.
IMMUNOTHERAPY
This personalized medicine requires genetic testing on tumors to determine if they can be treated with drugs targeted specifically for them. Opdivo (nivolumab), FDA approved in 2015, is the first immunotherapy drug for non-small cell lung cancer. In a clinical trial, it extended the lifespan of 30 percent of patients by two years.
Jenny White, whose story was told at the beginning of this chapter, credits this type of therapy with helping save her life. “Because I had cancer, my surgeon sent me to an oncologist after my surgery who suggested I have my tumor tested for a biomarker. It turned out to be positive for the EGFR mutation, which is more common in non-smokers, so I underwent chemotherapy targeted at that. My oncologist said that before that, I had an 85 percent chance of survival, but this would squash any rogue cells and get that estimate up to 95 percent,” she says.
What Happens If Lung Cancer Spreads?
One of the areas that lung cancer tends to spread, especially in women, is to the brain. While this is obviously not good, it does not mean that the situation is hopeless, says Lee M. Tessler, MD, a neurosurgeon and executive director of the Long Island Brain Tumor Center. “Once, if lung cancer spread to the brain, that was it. But now, we can use [new] techniques to treat it, and so people are living for years, even though their cancers had spread to the brain,” he says. And, he adds, “their quality of life is good too” — a message he is trying to bring not only to patients, but to their oncologists as well. See the chapter on brain cancer for a list of treatment techniques.