LUNG CANCER

The main function of the lungs is to exchange gases between the air we breathe and the blood. In the lungs, carbon dioxide is removed from the bloodstream and oxygen from inhaled air enters the bloodstream. The right lung has three lobes, while the left lung is divided into two lobes and a small structure called the lingula that is the equivalent of the middle lobe on the right. The major airways entering the lungs are the bronchi, which arise from the trachea. The bronchi branch into progressively smaller airways called bronchioles that end in tiny sacs known as alveoli where the exchange of oxygen and carbon dioxide occurs. The lungs and chest wall are covered with a thin layer of tissue called the pleura.

Lung cancers can arise in any part of the lung, but 90%-95% of cancers of the lung are thought to arise from the epithelial cells, the cells lining the larger and smaller airways (bronchi and bronchioles); for this reason, lung cancers are sometimes called bronchogenic cancers or bronchogenic carcinomas. Cancers also can arise from the pleura (mesotheliomas) or rarely from supporting tissues within the lungs, for example, the blood vessels.

Lung cancer is the most common cause of death due to cancer in both men and women throughout the world. The American Cancer Society estimated that 222,520 new cases of lung cancer in the U.S. will be diagnosed and 157,300 deaths due to lung cancer would occur in 2010. Approximately one out of every 14 men and women in the U.S. will be diagnosed with cancer of the lung at some point in their lifetime. Almost 70% of people diagnosed with lung cancer are over 65 years of age, while less than 3% of lung cancers occur in people under 45 years of age.

The incidence of lung cancer is strongly correlated with cigarette smoking, with about 90% of lung cancers arising as a consequence of tobacco use. The risk of lung cancer increases with the number of cigarettes smoked and the time over which smoking has occurred. Tobacco smoke contains over 4,000 chemical compounds, many of which have been shown to be cancer-causing or carcinogenic. The two primary carcinogens in tobacco smoke are chemicals known as nitrosamines and polycyclic aromatic hydrocarbons. The risk of developing lung cancer decreases each year following smoking cessation as normal cells grow and replace damaged cells in the lung. In former smokers, the risk of developing lung cancer begins to approach that of a nonsmoker about 15 years after cessation of smoking.

Passive smoking or the inhalation of tobacco smoke by nonsmokers who share living or working quarters with smokers, also is an established risk factor for the development of lung cancer. Research has shown that nonsmokers who reside with a smoker have a 24% increase in risk for developing lung cancer when compared with nonsmokers who do not reside with a smoker. An estimated 3,000 lung cancer deaths that occur each year in the U.S. are attributable to passive smoking. Air pollution from vehicles, industry, and power plants can raise the likelihood of developing lung cancer in exposed individuals. Up to 1% of lung cancer deaths are attributable to breathing polluted air, and experts believe that prolonged exposure to highly polluted air can carry a risk for the development of lung cancer similar to that of passive smoking.

Lung cancers are broadly classified into two types: small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). This classification is based upon the microscopic appearance of the tumor cells themselves. SCLC comprise about 20% of lung cancers and are the most aggressive and rapidly growing of all lung cancers. SCLC are strongly related to cigarette smoking, with only 1% of these tumors occurring in nonsmokers. SCLC metastasize rapidly to many sites within the body and are most often discovered after they have spread extensively. NSCLC are the most common lung cancers, accounting for about 80% of all lung cancers. NSCLC can be divided into three main types that are named based upon the type of cells found in the tumor: Adenocarcinomas are the most commonly seen type of NSCLC in the U.S. and comprise up to 50% of NSCLC. While adenocarcinomas are associated with smoking, like other lung cancers, this type is observed as well in nonsmokers who develop lung cancer. Most adenocarcinomas arise in the outer, or peripheral, areas of the lungs. Bronchioloalveolar carcinoma is a subtype of adenocarcinoma that frequently develops at multiple sites in the lungs and spreads along the preexisting alveolar walls. Squamous cell carcinomas were formerly more common than adenocarcinomas; at present, they account for about 30% of NSCLC. Also known as epidermoid carcinomas, squamous cell cancers arise most frequently in the central chest area in the bronchi. Large cell carcinomas, sometimes referred to as undifferentiated carcinomas, are the least common type of NSCLC.

Symptoms of lung cancer are varied depending upon where and how widespread the tumor is. Warning signs of lung cancer are not always present or easy to identify. A person with lung cancer may have various symptoms.  In up to 25% of people who get lung cancer, the cancer is first discovered on a routine chest X-ray or CT scan as a solitary small mass. These patients with small, single masses often report no symptoms at the time the cancer is discovered. The growth of the cancer and invasion of lung tissues and surrounding tissue may interfere with breathing, leading to symptoms such as cough, shortness of breath, wheezing, chest pain, and coughing up blood. If the cancer has invaded nerves it may cause shoulder pain that travels down the outside of the arm (called Pancoast's syndrome) or paralysis of the vocal cords leading to hoarseness. Invasion of the esophagus may lead to difficulty swallowing (dysphagia). If a large airway is obstructed, collapse of a portion of the lung may occur and cause infections (abscesses, pneumonia) in the obstructed area.

The stage of a cancer is a measure of the extent to which a cancer has spread in the body. Staging involves evaluation of a cancer's size and its penetration into surrounding tissue as well as the presence or absence of metastases in the lymph nodes or other organs. Staging is important for determining how a particular cancer should be treated, since lung-cancer therapies are geared toward specific stages. Staging of a cancer also is critical in estimating the prognosis of a given patient, with higher-stage cancers generally having a worse prognosis than lower-stage cancers.

Standard treatment of lung cancer can involve surgical removal of the cancer, chemotherapy, or radiation therapy, as well as combinations of these treatments. The decision about which treatments will be appropriate for a given individual must take into account the location and extent of the tumor as well as the overall health status of the patient.

As with other cancers, therapy may be prescribed that is intended to be curative (removal or eradication of a cancer) or palliative (measures that are unable to cure a cancer but can reduce pain and suffering). More than one type of therapy may be prescribed. In such cases, the therapy that is added to enhance the effects of the primary therapy is referred to as adjuvant therapy. An example of adjuvant therapy is chemotherapy or radiotherapy administered after surgical removal of a tumor in an attempt to kill any tumor cells that remain following surgery.

Surgical removal of the tumor is generally performed for limited-stage (stage I or sometimes stage II) NSCLC and is the treatment of choice for cancer that has not spread beyond the lung. About 10%-35% of lung cancers can be removed surgically, but removal does not always result in a cure, since the tumors may already have spread and can recur at a later time. Among people who have an isolated, slow-growing lung cancer removed, 25%-40% are still alive five years after diagnosis. Surgery for lung cancer is a major surgical procedure that requires general anesthesia, hospitalization, and follow-up care for weeks to months. Following the surgical procedure, patients may experience difficulty breathing, shortness of breath, pain, and weakness. The risks of surgery include complications due to bleeding, infection, and complications of general anesthesia.

Radiation therapy may be employed as a treatment for both NSCLC and SCLC. Radiation therapy uses high-energy X-rays or other types of radiation to kill dividing cancer cells. Radiation therapy can be given if a person refuses surgery, if a tumor has spread to areas such as the lymph nodes or trachea making surgical removal impossible, or if a person has other conditions that make them too ill to undergo major surgery. Radiation therapy generally only shrinks a tumor or limits its growth when given as a sole therapy, and in 10%-15% of people it leads to long-term remission and palliation of the cancer. Combining radiation therapy with chemotherapy can further prolong survival when chemotherapy is administered. Radiation therapy can have several side effects, including fatigue and lack of energy. A reduced white blood cell count (rendering a person more susceptible to infection) and low blood platelet levels (making blood clotting more difficult and resulting in excessive bleeding) also can occur with radiation therapy. If the digestive organs are in the field exposed to radiation, patients may experience nausea, vomiting, or diarrhea. Radiation therapy can irritate the skin in the area that is treated, but this irritation generally improves with time after treatment has ended.

Both NSCLC and SCLC may be treated with chemotherapy. Chemotherapy refers to the administration of drugs that stop the growth of cancer cells by killing them or preventing them from dividing. Chemotherapy may be given alone, as an adjuvant to surgical therapy, or in combination with radiotherapy. Chemotherapy is the treatment of choice for most SCLC, since these tumors are generally widespread in the body when they are diagnosed. Only half of people who have SCLC survive for four months without chemotherapy. With chemotherapy, their survival time is increased up to four- to fivefold. Chemotherapy alone is not particularly effective in treating NSCLC, but when NSCLC has metastasized, it can prolong survival in many cases. Unfortunately, the drugs used in chemotherapy also kill normally dividing cells in the body, resulting in unpleasant side effects. Damage to blood cells can result in increased susceptibility to infections and difficulties with blood clotting (bleeding or bruising easily). Other side effects include fatigue, weight loss, hair loss, nausea, vomiting, diarrhea, and mouth sores. The side effects of chemotherapy vary according to the dosage and combination of drugs used and may also vary from individual to individual.

Since no therapy is currently available that is absolutely effective in treating lung cancer, patients may be offered a number of new therapies that are still in the experimental stage, meaning that doctors do not yet have enough information to decide whether these therapies should become accepted forms of treatment for lung cancer. New drugs or new combinations of drugs are tested in so-called clinical trials, which are studies that evaluate the effectiveness of new medications in comparison with those treatments already in widespread use. Experimental treatments known as immunotherapy are being studied that involve the use of vaccine-related therapies or other therapies that attempt to utilize the body's immune system to fight cancer cells.

Although there have been moderate advances in treatment, mortality and the threat of recurrences remain problematic. Only 50% of stage III or stage IV cancer patients are alive at 1 year and 8 months, respectively even with the most advanced and comprehensive treatment. Overall, only 16% of lung cancer survivors are alive 5 years after diagnosis. Cessation of smoking is the most effective means of preventing lung cancer.

Natural Killer or NK cells may be important in limiting lung cancer growth and metastases. Multiple studies have shown that Enercel^® is a potent activator of NK cell function. In addition, Enercel^® showed benefit in an animal model of rat mammary (breast) gland cancer. Escalating IM Enercel^® doses up to 1 ml/day for 10 days were assessed. After 10 days, the animals showed a clear improvement in their general wellness as manifested by greater mobility, friskiness and an increase in body weight as compared to placebo-treated controls. Tumor growth was arrested, and sometimes regressed, in a high proportion of lesions in the treated rats. Some tumors developed a characteristic central lesion consistent with tumor breakdown on histopathologic specimens. Statistical evaluation demonstrated that the survival of the test animals was significantly greater than that of the controls (p <0.01). The clinical and pathologic benefits of Enercel^® were dose-dependent. There was no difference in end points between animals treated with low-dose (0.05 ml/day) Enercel^® than in untreated controls. Thus, Enercel^® treatment was beneficial in a rat model of induced mammary tumors in a dose-dependent fashion. All but the lowest dose was successful. Tumor regression, improved clinical signs and greater survival were observed in treated animals compared to no response in placebo-treated ones.

Enercel^® was shown in a clinical trial to be beneficial in late-stage pancreatic carcinoma. Eighty-seven patients with stage III or IV pancreatic cancer were enrolled in this trial. A questionnaire was devised to measure selective aspects of quality of life.  A survival curve was analyzed; and group follow-up was for twelve months. Daily doses of Enercel^® 4 cc IM were administered during the entire study period. Sublingual and oral doses were also added for an additional 2.5 cc administered in four daily doses. A significant, beneficial effect was noted on several clinical parameters:  pain, appetite, nausea and vomiting, emotional state and physical function. Compared with historical controls with this stage and type of cancer, 1-year survival was significantly improved. Sixty subjects were still alive at 1 year.  The results of this study revealed that patients with advanced pancreatic cancer treated for 1 year with Enercel^® had a significant improvement on selective aspects of quality of life and survival compared to historical controls.

Enercel^® has been beneficial in multiple patients with lung cancer. Improved quality of life, survival, decreased side-effects of chemotherapy, tumor regression and decreased metastases were all noted. As a result of this patient experience, a major European country has approved a comprehensive study, “Open-Label Study of Enercel^® in Stage I, II, III and IV Lung Cancer Patients That Are Treatment Naïve or Have Failed Standard Medical Therapy” to begin later in 2011. If your health care practitioner believes that immune system suppression and/or energy depletion plays a role in your lung cancer, then Enercel^® may be very beneficial for you.