Screening for Lung Cancer
If lung cancer can be found early, it has fairly good survival rates. The question is, how do we find early stage lung cancers? Screening has long been found to make a significant difference in the early detection of certain cancers with the result of better treatment at an earlier stage and thus improved survival. PAP smears have been done for a number of years for cervical cancer and in doing so, the risk of cervical cancer, and thus, the death rate from cervical cancer has decreased considerably. Colonoscopies and removal of pre-cancerous polyps has resulted in the decline in deaths from colon cancer. Mammograms resulted in the earlier detection of breast cancers. Detection at an earlier stage allowed for less radical surgery to be done successfully with subsequent improvement in survival from breast cancer. In the past, both chest x-rays and sputum cytology have been evaluated as methods to detect lung cancer at an earlier stage but neither of these procedures were found to improve overall long-term survival.
The vast majority of patients that are operated on in our practice have their cancers found on a chest x-ray that was done for another reason. Commonly, patients have chest x-rays as part of a pre-operative exam for another type of surgical procedure, as part of a physical exam, as part of a job physical, or as the result of trauma in a car wreck or some other accident and when the chest x-rays are evaluated they are found to contain a mass that is then evaluated further and found to be a lung cancer. Even though most of the cancers that we operate on are found on chest x-rays, chest x-rays are not very effective for finding lung cancer and routine chest x-rays are no longer used to screen for lung cancer.
The only procedure currently available for lung cancer screening before symptoms are present is a spiral (or helical) CAT scan. A spiral CAT scan is similar to a conventional CAT scan which you may have seen before but is performed more quickly and results in less exposure to radiation. For a screening technique to be successful, it needs to be both sensitive, that is accurate in detecting the disease in the early stages, but also specific, meaning it does not pick up too many insignificant findings. One problem with CAT scans are that they can pick up spots in the lungs that are not cancerous. This can lead to unnecessary procedures to help diagnose the findings. There is also a significant risk of exposure to radiation from CAT scans. It is clear that screening for lung cancer with CAT scans should not be taken lightly.
In spite of the draw backs of CAT scanning for lung cancer screening, we know that there is a much better chance of curing small, early stage lung cancer than those found in later stages. Approximately fifteen years ago, the radiologists at Cornell Medical Center in New York began a lung cancer screening program. Their results were published in the October 2006 New England Journal of Medicine which included 31,000 patients who were considered to be at a high risk for lung cancer. It was found that the patients who were diagnosed with lung cancer on an annual CAT scan screening had an estimated cure rate of 80%. The research showed that when cancers were found at the earliest stage (1cm or less) and are properly removed with surgery that the patients had a 92% chance of being cured. 85% of the patients who were diagnosed with the annual screening had this curable early stage cancer. It was noted that the chest x-rays done at the same time as the CAT scans missed 85% of the early stage cancer which were detected by the CAT scans. By contrast, 95% of patients who are diagnosed with lung cancer after they begin having symptoms will ultimately die of their disease. The studies at Cornell have now expanded into international study groups known as the International Early Lung Cancer Action Program (IELCAP). In order to enroll in the IELCAP study, you must be 40 years of age, have smoked greater than 100 cigarettes, have a family history of lung cancer, or a history of exposure to significant second hand smoke or occupational chemicals that can cause lung cancer. The results from Cornell look very promising, however. If you or your loved one happens to be the patient that has the 1cm or less tumor diagnosed with the screening process then the screening may be productive for you.
The Staging and Treatment of Lung Cancer
How is lung cancer treated?
In order to know about the treatment of lung cancer, you should know the stages of lung cancer and the types of lung cancer. The two types of lung cancer are non-small cell lung cancer, which is the most common kind of cancer and makes up at least 80% of all cases. Small cell lung cancer makes up around 20% of all lung cancer cases. Because of small cell lung cancer’s rapid reproduction, it is particularly susceptible to chemotherapy and in only a very few selected cases will a patient with small cell cancer be a candidate for surgery. It is almost always associated with smoking.
The staging of lung cancer predicts how far the cancer has progressed. Clinical staging is based on scans, physical exam, and limited biopsies, such as a needle biopsy. Surgical staging is staging that is determined after a tumor and lymph nodes have been removed. Lung cancer is divided into four stages. Stage I means that the cancer is localized to the lung and there is no cancer in the surrounding lymph nodes. Stage II means it has spread to the lymph nodes closest to the affected lung or that it has spread instead to the chest wall or the outer covering of the heart, known as the pericardium. Stage III means that the cancer has spread to the lymph nodes in the central part of the chest, known as the mediastinum, or that there is more than one tumor in the affected lung. If the tumor has grown into another major structure inside your chest or if lymph node on the other side of the chest have cancer within them, this would also be a stage III cancer. Stage IV usually means that the cancer has spread to another part of the body, such as the liver, brain, or bones. In general, surgery is the best option for stage I and stage II non-small cell cancer, sometimes accompanied by post-operative chemotherapy. For stage III and stage IV non-small cell cancer, a combination of chemotherapy and radiation therapy is often used.
Prior to deciding upon the type of treatment for lung cancer, accurate staging must be performed. There are published standards that we adhere to in our practice which are called the National Comprehensive Cancer Network Standards. These recommendations are followed and used in the staging process.
The best standard of diagnosis of lung cancer is a CAT scan. It is important to not only know whether or not the patient has cancer but also know whether or not the cancer has spread. In addition to the CAT scan, a very useful test which almost all cancer patients receive now is called a PET (Positive Emission Tomography) scan. In this particular scan, radioactive glucose is given to the patient and theoretically, cells that are dividing rapidly will use the glucose as an energy source. Because the glucose is radioactively labeled, it will show up as a “hot spot” on the scan. Tumors are often fast growing and therefore use more glucose and show up as a hot spot on the PET scan. The PET scan is particularly useful to look for disease outside the chest cavity. The degree of uptake within the mass also has some predictive value as to the degree of aggressiveness of the tumor.
As helpful as PET scans are, they are at best 80% to 85% accurate as far as predicting the extent of the disease.
PET scans are not particularly accurate in predicting whether or not a patient has brain metastasis. In fact, 10% of patients that are otherwise asymptomatic and have been diagnosed with lung cancer will have brain metastasis at the time of diagnosis. An MRI is recommended to complete the staging along with the PET scan to make sure there is no spread to the brain. With the degree of accuracy of a PET scan being 10% to 15% false positive or false negative, it is our practice to recommend a biopsy of PET scan positive areas before confirming they are in fact metastasis from the primary lung cancer. Objective data, such as needle biopsies and surgical biopsies, should be performed to confirm whether or not the PET scan is accurate before making definite recommendations as to the treatment plan for the patient with lung cancer. Sometimes a bone scan is recommended, along with the PET scan to predict whether or not there has been any spread to the bones.
Once an accurate objective staging process has been established then treatment recommendations can be made.
Surgery as a treatment option
Surgery has been shown to be the most effective form of treatment for lung cancer. In order for surgery to be effective, the tumor must be confined to the same side of the chest cavity where it is located and the patient must be able to tolerate having the surgery performed from a heart and lung standpoint. Surgery is most effective for stage I (tumor without any spread to the lymph nodes) or stage II (tumors that have direct spread to the sack around the heart, the diaphragm, the chest wall, or the lymph nodes close to the tumor). An adequate cancer operation should consist of 1) evaluation of the wind pipe and bronchial tubes with a scope known as a bronchoscope to rule out any unexpected tumors within the bronchus or to make plans about where to divide the bronchus in removing the lung; 2) evaluation of the lymph nodes behind the breast bone known as the mediastinum through a procedure known as a mediastinoscopy where a scope is placed behind the breast bone and pieces of lymph nodes are obtained or through a procedure known as an EBUS where an ultrasound guided bronchoscope is placed and needle aspiration of lymph nodes behind the breast bone and adjacent to the wind pipe are carried out. This procedure is important to rule out false negative PET scan results and make sure there is no spread to the lymph nodes in this area, which would make the patient a stage III patient and thus inoperable at this point in time. 3) an adequate surgical procedure should be complete removal of the tumor to include the lobe of the lung that is affected with the cancer. There are three lobes on the right side and two lobes on the left side. Pulmonary testing prior to the surgery would determine whether or not the patient is a candidate for a lobectomy. 4) Complete removal of any lymph nodes in the area known as the mediastinum. This not only assists in surgical staging but also has been shown to increase the cure rate from the cancer. The size of the tumor, the number of lymph nodes involved, and other associated condition, such as scarring within the chest would predict whether or not this surgical procedure can be performed using minimally invasive techniques, known as video assisted thoracic surgery (VATS). Currently in our practice, if the anatomy is suitable, we provide a high percentage of pulmonary resections using VATS technique.
Chemotherapy involves the use of drugs to kill cancer cells. For most lung cancers now, platinum based therapy is used. Chemotherapy is indicated for patients with stage III and IV disease. There have been studies that have shown a survival benefit to chemotherapy given after removal of stage II lung cancers. There is also enthusiasm for novel targeted therapies for non-small cell lung cancer. There are molecular markers in every tumor that can be identified and by targeting chemotherapy to attack different areas of the tumor cell and molecular pathways, it is hoped that the effectiveness of chemotherapy will be increased while decreasing the toxicity of the drugs. Targeted therapy is in its infancy and at the present time we send resected tumor specimens, not only to be studied in a tumor bank but also for special studies to determine what chemotherapeutic agents will be most effective.
Conventional external beam radiation therapy
Conventional external beam radiation therapy is often used to treat patients that are inoperable because of distant spread or because they are inoperable from medical problems, such as heart disease or severe emphysema. Conventional external beam radiation therapy is delivered as a daily dose over a period of 35 daily fraction administered. When the radiation is delivered either to the tumor itself or to the lymph nodes in the mediastinum, it is fairly successful with local control. Five year survival rates range widely but have averaged between 20% and 30% with radiation of the lung. Unfortunately, standard external beam radiation is limited by the worry of damaging the normal surrounding tissue. Because of this, recent developments in radiation therapy technology have attempted to apply very high doses to small targets, either as a single dose or a brief fractionated regimen. This is known as stereotactic body radiotherapy. It often goes by the trade names of Trilogy or CyberKnife. This technique requires rigid patient immobilization and methods of managing the target through tumor tracking, restriction of tumor motion, or control of respiration. The results of stereotactic body radiotherapy are promising with respect to local control rates and tolerability. Local control rates in the range of 50% to 60% have been reported but it is not clear whether these local control rates are going to extrapolate into higher survival rates. Stereotactic radiotherapy is also limited as to the size of the tumor that can be radiated (generally anything less than 5cm) and stereotactic radiotherapy cannot be given close to vital structures within the chest, such as the heart, the aorta, and major bronchi without worrying that there can be damage to these structures as well.
Radiofrequency ablation is another alternative form of treatment and is generally reserved for patients that are medically inoperable. It is useful for localized tumors in patients that have medical conditions that deem them inoperable for surgery. Radiofrequency ablation (RFA) involves the application of high frequency electrical current to heat and coagulate target tissue. Radiofrequency ablation consists of an alternating current which moves from an active electrodes that are placed within the tumor in the CAT scan suite to dispersive electrodes placed on the patient. As the radiofrequency energy moves from the active electrode to the dispersive electrode and then back to the active electrode, frictional heating of the tissue occurs and results in instantaneous cell death due to protein destruction and death of tumor cells. RFA is more applicable to tumors 2 cm or less and also tumor that are located in the periphery of the lung. It is not recommended for patients with widespread disease nor with patients with tumors that are adjacent to major structures, such as the diaphragm, large blood vessels, large bronchi, or the chest wall.
If you or a loved one has been diagnosed as having lung cancer, seek appropriate care. Studies have shown that institutions that perform a number of thoracic surgical procedures have higher survival rates with less complications.
Make sure that you seek advice from someone who is well versed in the treatment of lung cancer. Lung cancer is a multi-specialty disease and the decision about treatment should be based upon a variety of opinions from an Oncologist, a Radiation Oncologist, and a surgeon. At Northside Hospital, we present lung cancer patients to a multi-disciplinary board and therefore obtain a wide variety of opinions about treatment before any treatment is decided upon and recommended to the patient. This multi-disciplinary approach to lung cancer has proven to be most effective. Before a patient is deemed inoperable, it would be wise to consult with a surgeon who regularly performs lung cancer operations.
It is scary to have a diagnosis of lung cancer. It is wise to remember that statistics are applied to large groups of patients and do not necessarily predict an individual’s ultimate outcome. No matter how daunting the statistics seem to be stacked against you with a diagnosis of lung cancer, remember that there are people who survive even the highest stages of lung cancer.