Around 1950’s, lung cancer became the most common cause of cancer deaths in men, and in the mid 1980’s, it became the leading cause of cancer deaths in women. Lung cancer deaths have begun to decline in both men and women, reflecting a decrease in smoking.
The term lung cancer, or bronchogenic carcinoma, refers to malignancies that originate in the airways or lung tissue. Approximately 95 percent of all lung cancers are classified as either small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC). This distinction is essential for staging, treatment, and prognosis. Other cell types comprise about 5 percent of malignancies arising in the lung.
A number of environmental and life-style factors have been associated with the subsequent development of lung cancer, of which cigarette smoking is the most important. The primary risk factor for the development of lung cancer is cigarette smoking, which is estimated to account for approximately 90 percent of all lung cancers. The risk of developing lung cancer for a current smoker of one pack per day for 40 years is approximately 20 times that of someone who has never smoked. Factors that increase the risk of developing lung cancer in smokers include the extent of smoking and exposure to other carcinogenic factors, such as asbestos.
Thus, the most important aspects of lung cancer prevention are preventing people from starting to smoke and inducing those who already smoke to stop. In individuals who do quit smoking, the risk of developing lung cancer gradually falls for about 15 years before it levels off and remains about twice that of someone who never smoked.
Radiation therapy can increase the risk of a second primary lung cancer in patients who have been treated for other malignancies. In women who receive radiation following a mastectomy for breast cancer, there appears to be an increased risk of lung cancer among smokers. Similarly, radiation therapy for Hodgkin lymphoma has been associated with an increased risk of secondary lung cancer.
Improved radiation techniques limit the dose of radiation to nonmalignant tissue, and contemporary equipment and dose planning is thought to significantly reduce the risk for secondary lung cancer.
Environmental factors have been associated with an increased risk for developing lung cancer. These include exposure to second-hand smoke, asbestos, radon, metals (arsenic, chromium, and nickel), ionizing radiation, and polycyclic aromatic hydrocarbons.Pulmonary fibrosis:
Several studies have shown that the risk for lung cancer is increased about sevenfold in patients with pulmonary fibrosis. This increased risk appears to be independent of smoking.HIV infection:
The incidence of lung cancer among individuals infected with HIV appears to be increased compared to that seen in uninfected controls.
Genetic factors can affect both the risk for and prognosis from lung cancer. Although the genetic basis of lung cancer is still being investigated, there is a clearly established familial risk.Dietary factors:
Epidemiologic evidence has suggested that various dietary factors (antioxidants, cruciferous vegetables, phytoestrogens) may reduce the risk of lung cancer, but the role of these factors is not well established. Attempts to confirm these epidemiologic findings and to decrease the incidence of lung cancer in high-risk patients have not been successful. As example, the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study actually showed an increase in lung cancer among smokers with dietary supplementation of beta-carotene.
The diagnosis of lung cancer is primarily based upon evaluation of individuals with symptoms. Screening for lung cancer has not been widely used, since chest radiography and sputum cytology have not been shown to reduce mortality from lung cancer.
Studies have shown that a large percentage of lung cancers detected by CT screening are early stage tumors, which have a favorable prognosis. These findings led to the randomized National Lung Screening Trial that compared CT screening with chest x-ray. This trial demonstrated a 20 percent decrease in lung cancer mortality in heavy smokers who were screened annually for three years.
Unfortunately the majority of patients with lung cancer have advanced disease at clinical presentation. This reflects the aggressive nature of the disease, the frequent absence of symptoms until locally advanced or metastatic disease is present, and the lack of an effective screening test.
Symptoms may result from local effects of the tumor, from regional or distant spread, or from distant effects not related to metastases (paraneoplastic syndromes). Approximately three-fourths of patients have one or more symptoms at the time of diagnosis.
There are a wide range of symptoms due to lung cancer, the most common of which are cough, hemoptysis, chest pain, and dyspnea.
Cough is present in 50 to 75 percent of lung cancer patients at presentation and occurs most frequently in patients with squamous cell and small cell carcinomas, because of their tendency to involve central airways. The new onset of cough in a smoker or former smoker should raise suspicion that lung cancer is present.
Hemoptysis (coughing up blood) is reported by 25 to 50 percent of patients who are diagnosed with lung cancer, although bronchitis is the most common cause of this symptom. Any amount of hemoptysis can be alarming to the patient, and large volumes of hemoptysis may cause asphyxia.
Chest pain is present in approximately 20 percent of patients presenting with lung cancer. It can be quite variable in character and is more common in younger compared to older patients. Pain is typically present on the same side of the chest as the primary tumor. Dull, aching, persistent pain may occur but the presence of pain does not necessarily preclude a good prognosis.
Dyspnea (shortness of breath) is a common symptom in patients with lung cancer at the time of diagnosis, occurring in approximately 25 percent of cases. Dyspnea may be due to airway obstruction, tumor spread, collapsed lung or fluid accumulation around the lung. Partial obstruction of a bronchus may cause a localized wheeze, heard by the patient or by the clinician on auscultation.Pulmonary function testing may be useful in a patient with dyspnea due to lung cancer. Unilateral paralysis of the diaphragm may be due to damage of the phrenic nerve. Patients may be asymptomatic or report shortness of breath.
Persistent hoarseness in a smoker increases the concerns for possible laryngeal cancer or lung cancer.
Patients with malignant effusions (Cancer fluid around the lungs) are considered incurable and managed palliatively. Although malignant pleural effusions can cause dyspnea and cough, approximately one-fourth of patients who have lung cancer and pleural metastases are asymptomatic. Although a malignant pleural effusion precludes curative resection, not all pleural effusions in patients with lung cancer are malignant. A benign pleural effusion may occur in a patient with a resectable lung cancer. In a patient with a pleural effusion, the presence of tumor needs to be confirmed or excluded so that a chance for curative resection is not missed. Surgical thoracoscopy or medical pleuroscopy should be considered prior to surgical resection of a primary lesion.
Lung cancer can spread to any part of the body tissue. Metastatic spread may result in the presenting symptoms or may occur later in the course of disease.The most frequent sites of distant metastasis are the liver, adrenal glands, bones, and brain.
The initial stage in management is to assess whether the patient has a non-small cell lung cancer (NSCLC) or a small cell lung cancer (SCLC), the stage of the disease, and the overall performance status of the patient
A tissue diagnosis is necessary to determine whether a lung cancer is a NSCLC or an SCLC, as well as to rule out the possibility that disease represents lung metastasis from a primary tumor at another site. This information is critical for treatment planning. A biopsy of the lung can be performed via bronchoscopy, CT guided needle biopsy or open surgical biopsy.
Staging for NSCLC is critical in determining the appropriate treatment for a patient with resectable disease and avoiding unnecessary surgery in advanced disease.
Staging of SCLC is considered limited (confined to one lung) or extensive (beyond one lung) disease. This distinction is important since patients with limited disease may benefit from thoracic radiation therapy in addition to systemic chemotherapy.
Treatment of lung cancer, whether with surgery, chemotherapy, radiation therapy or a combination of these, can be associated with substantial toxicity. Patients with significant impairment due to their lung cancer or other conditions may not be able to withstand resection or alternatively aggressive chemoradiotherapy. Performance status of the patient will need to be factored in the decision process of treatment options.PET and PET-CT: Positron emission tomography (PET), alone or integrated with computed tomography (CT), is useful in the initial staging to identify sites of tumor involvement
Non-small cell lung cancer; surgical resection offers the best opportunity for long-term survival and cure in patients with resectable NSCLC. The appropriateness of surgical resection of candidates with known or suspected NSCLC includes preoperative staging and an assessment of performance status with concurrent medical conditions and pulmonary function to allow prediction of postoperative function.
A patient with lung cancer may be "resectable" by virtue of having a surgically removable NSCLC, but may not be "operable" due to poor pulmonary function or multiple medical conditions. Advances in surgical technique, the role of limited resection, and postoperative care may provide the opportunity for surgical resection in patients who previously might not have been considered candidates for aggressive treatment.
Small cell lung cancer is a disseminated (scattered) disease in most patients, even at presentation. Thus systemic chemotherapy is an integral part of the initial treatment. Patients with limited stage disease are primarily treated with a combination of chemotherapy and radiation therapy, since the addition of radiation therapy has been shown to prolong survival compared to chemotherapy therapy alone. Surgery is not used except in the rare patient who presents with a solitary pulmonary nodule without metastases or regional lymph node involvement.
Lung cancer is the most common cause of cancer mortality worldwide for both men and women. Cigarette smoking is responsible for approximately 90 percent of cases of lung cancer. Thus prevention of smoking and cessation of smoking offer the most important route to decreasing the morbidity and mortality associated with this disease.
Lung cancer is divided into several histologic types. The most important distinction is between non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).
All of these symptoms can also be caused by conditions that are not lung cancer. But if you have these symptoms, you should let your doctor or nurse know.
— Yes. If your doctor suspects that you have lung cancer, she or she will do an exam and a chest X-ray. If the chest X-ray shows a spot that looks like it could be cancer, he or she will probably follow up with other tests. These can include:
— Cancer staging is a way in which doctors find out how far a cancer has spread. The right treatment for you will depend, in part, on the stage of your lung cancer. Your treatment will also depend on the type of lung cancer you have, your age, and your other health problems.
— Most people with lung cancer have one or more of the following treatments: Surgery — Lung cancer can sometimes be treated with surgery to remove the cancer. Radiation therapy — Radiation kills cancer cells. Chemotherapy — Chemotherapy is the term doctors use to describe a group of medicines that kills cancer cells. Targeted therapy — Some medicines work only for cancers that have certain characteristics. Your doctor might test you to see if you have a kind of lung cancer that would respond to these medicines.
People with lung cancer also receive treatment for any symptoms they have. For example, if you have trouble breathing because fluid has collected around your lungs, your doctor can drain the fluid to help you breathe more easily.
— After treatment, you will be checked every so often to see if the lung cancer comes back.
Follow up tests usually include exams, chest X-rays, or CT scans. You should also watch for the symptoms listed above, because having those symptoms could mean the cancer has come back. Tell your doctor or nurse if you have any symptoms.
— If the lung cancer comes back, you might have more chemotherapy, radiation, or surgery.
— Maybe. The best way to avoid getting lung cancer is to not smoke. People who smoke have a much higher chance than those who don’t smoke of getting lung cancer. If you smoke, you can reduce your chance of getting lung cancer by quitting smoking.
— It is important to follow all your doctors’ instructions about visits and tests.
It’s also important to talk to your doctor about any side effects or problems you have during treatment.Getting treated for lung cancer involves making many choices, such as what treatment to have and when.