Treatment for 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 localization 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 order to be certain that all tumor cells are killed.
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 may not be possible if the cancer is too close to the trachea or if the person has other serious conditions (such as severe heart or lung disease) that would limit their ability to tolerate an operation. Surgery is less often performed with SCLC because these tumors are less likely to be localized to one area that can be removed.
The surgical procedure chosen depends upon the size and location of the tumor. Surgeons must open the chest wall and may perform a wedge resection of the lung (removal of a portion of one lobe), a lobectomy (removal of one lobe), or a pneumonectomy (removal of an entire lung). Sometimes lymph nodes in the region of the lungs are also removed (lymphadenectomy). 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: 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 may be given as curative therapy, palliative therapy (using lower doses of radiation than with curative regimens), or as adjuvant therapy in combination with surgery or chemotherapy. The radiation is either delivered externally, by using a machine that directs radiation toward the cancer, or internally through placement of radioactive substances in sealed containers within the area of the body where the tumor is localized. Brachytherapy is a term used to describe the use of a small pellet of radioactive material placed directly into the cancer or into the airway next to the cancer. This is usually done through a bronchoscope.
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, yet in 10% -15% of people it leads to long-term remission and palliation of the cancer. Combining radiation therapy with chemotherapy can further increase the chances of survival when chemotherapy is administered. External radiation therapy can generally be carried out on an outpatient basis, while internal radiation therapy requires a brief hospitalization. A person who has severe lung disease in addition to a lung cancer may not be able to receive radiotherapy to the lung. A type of external radiation therapy called the "gamma knife" is sometimes used to treat single brain metastases. In this procedure, multiple beams of radiation are focused on the tumor over a few minutes to hours while the head is held in place by a rigid frame.
For external radiation therapy, a process called simulation is necessary prior to treatment. Using CT scans, computers, and precise measurements, simulation maps out the exact location where the radiation will be delivered, called the treatment field or port. This process usually takes 30 minutes to two hours. The external radiation treatment itself generally is done over four or five days a week for several weeks.
Radiation therapy does not carry the risks of major surgery, but it can have unpleasant 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) can also 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.
Chemotherapy: 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. While a number of chemotherapeutic drugs have been developed, the class of drugs known as the platinum-based drugs have been the most effective in treatment of lung cancers.
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 have metastasized, it can prolong survival in many cases.
Chemotherapy may be given as pills, as an intravenous infusion, or as a combination of the two. Chemotherapy treatments are usually given in an outpatient setting. A combination of drugs is given in a series of treatments, called cycles, over a period of weeks to months, with breaks in between cycles. 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. Medications have been developed that can treat or prevent many of the side effects of chemotherapy. The side effects generally disappear during the recovery phase of the treatment or after its completion.
Brain prophylactic radiation: SCLC often spreads to the brain. Sometimes people with SCLC that is responding well to treatment are treated with radiation therapy to the head to treat very early spread to the brain (called micrometastasis) that is not yet detectable with CT or MRI scans and has not yet produced symptoms. Brain radiation therapy can cause short-term memory problems, fatigue, nausea, and other side effects.
Treatment of recurrence: Lung cancer that has returned following treatment with surgery, chemotherapy, and / or radiation therapy is called recurrent or relapsed. If a recurrent cancer is confined to one site in the lung, it may be treated with surgery. Relapsed tumors generally do not respond to the chemotherapeutic drugs that were previously administered. Since platinum-based drugs are generally used in initial chemotherapy of lung cancers, these agents are not useful in most cases of recurrence. A type of chemotherapy referred to as second-line chemotherapy is used to treat recurrent cancers that have previously been treated with chemotherapy, and a number of second-line chemotherapeutic regimens have been proven effective at prolonging survival. People with recurrent lung cancer who are well enough to tolerate therapy are also good candidates for experimental therapies (see below), including clinical trials.
Targeted therapy: One alternative to standard chemotherapy is the drug erlotinib (Tarceva) which may be used in patients with NSCLC who are no longer responding to chemotherapy. It is a so-called targeted drug, a drug that more specifically targets cancer cells, resulting in less damage to normal cells. Erlotinib targets a protein called the epidermal growth factor receptor (EGFR) that helps cells to divide. This protein is found at abnormally high levels on the surface of some types of cancer cells, including many cases of non-small cell lung cancer. Erlotinib is taken by mouth in pill form.
Other attempts at targeted therapy include drugs known as antiangiogenesis drugs, which block the development of new blood vessels within a cancer. Without adequate blood vessels to supply oxygenated blood, the cancer cells will die. The antiangiogenic drug bevacizumab (Avastin) has recently been found to prolong survival in advanced lung cancer when it is added to the standard chemotherapy regimen. Bevacizumab is given intravenously every two to three weeks. However, since this drug may cause bleeding, it is not appropriate for use in patients who are coughing up blood, if the lung cancer has spread to the brain, or in people who are receiving anticoagulation therapy ( "blood thinner" medications). Bevacizumab is also not used in cases of squamous cell cancer, because it leads to bleeding from this type of lung cancer.
Photodynamic therapy (PDT): One newer therapy used for different types and stages of lung cancer (as well as some other cancers) is photodynamic therapy. In photodynamic treatment, a photosynthesizing agent (such as a porphyrin, a naturally occurring substance in the body) is injected into the bloodstream a few hours prior to surgery. During this time, the agent deposits itself selectively in rapidly growing cells such as cancer cells. A procedure then follows in which the physician applies a certain wavelength of light through a handheld wand directly to the site of the cancer and surrounding tissues. The energy from the light activates the photosensitizing agent, causing the production of a toxin that destroys the tumor cells. PDT has the advantages that it can precisely target the location of the cancer, is less invasive than surgery, and can be repeated at the same site if necessary. The drawbacks of PDT are that it is only useful in treating cancers that can be reached with a light source and is not suitable for treatment of extensive cancers. Research is ongoing to further determine the effectiveness of PDT in lung cancer.
Radiofrequency ablation (RFA): Radiofrequency ablation is being studied as an alternative to surgery, particularly in cases of early stage lung cancer. In this newer type of treatment, a needle is inserted through the skin into the cancer, usually under guidance by CT scanning. Radiofrequency (electrical) energy is then transmitted to the tip of the needle where it produces heat in the tissues, killing the cancerous tissue and closing small blood vessels that supply the cancer. RFA usually is not painful and has been approved by the US Food and Drug Administration for the treatment of certain cancers including lung cancers. Studies have shown that this treatment can prolong survival similarly to surgery, when used to treat early stages of lung cancer, but without the risks of major surgery and the prolonged recovery time associated with major surgical procedures.
