LCLC is differentiated from SCLC primarily by the larger size of the anaplastic cells, a higher cytoplasmic-to-nuclear size ratio, and a lack of "salt-and-pepper" chromatin. Symptoms
Many of the symptoms of NSCLC can be signs of other diseases, but having chronic or overlapping symptoms may be a signal of the presence of the disease. Some symptoms are indicators of less advanced cases, while some may signal that the cancer has spread. Some of the symptoms of less advanced cancer include chronic cough, coughing up blood, hoarseness, shortness of breath, wheezing, chest pain, weight loss, and loss of appetite. A few more symptoms associated with the early progression of the disease are feeling weak, being very tired, having trouble swallowing, swelling in the face or neck, and continuous or recurring infections such as bronchitis or pneumonia. Signs of more advanced cases include bone pain, nervous-system changes (headache, weakness, dizziness, balance problems, seizures), jaundice, lumps near the surface of the body, numbness of extremities due to Pancoast syndrome, and nausea, vomiting, and constipation brought on by hypercalcemia. Some more of the symptoms that indicate further progression of the cancer include shortness of breath, superior vena cava syndrome, trouble swallowing, large amounts of mucus, weakness, fatigue, and hoarseness. Cause
Smoking is by far the leading risk factor for lung cancer. Cigarette smoke contains more than 6,000 components, many of which lead to DNA damage (see table of tobacco-related DNA damages in Tobacco smoking).
Non-small-cell lung carcinoma (NSCLC) is any type of epithelial lung cancer other than small-cell lung carcinoma (SCLC). NSCLC accounts for about 85% of all lung cancers. As a class, NSCLCs are relatively insensitive to chemotherapy, compared to small-cell carcinoma. When possible, they are primarily treated by surgical resection with curative intent, although chemotherapy has been used increasingly both preoperatively (neoadjuvant chemotherapy) and postoperatively (adjuvant chemotherapy). Types
The most common types of NSCLC are squamous-cell carcinoma, large-cell carcinoma, and adenocarcinoma, but several other types occur less frequently. A few of the less common types are pleomorphic, carcinoid tumor, salivary gland carcinoma, and unclassified carcinoma. All types can occur in unusual histologic variants and as mixed cell-type combinations. Nonsquamous-cell carcinoma almost occupies the half of NSCLC. In the tissue classification, the central type contains about one-ninth.Sometimes, the phrase "not otherwise specified" (NOS) is used generically, usually when a more specific diagnosis cannot be made. This is most often the case when a pathologist examines a small number of malignant cells or tissue in a cytology or biopsy specimen.Lung cancer in people who have never smoked is almost universally NSCLC, with a sizeable majority being adenocarcinoma.On relatively rare occasions, malignant lung tumors are found to contain components of both SCLC and NSCLC. In these cases, the tumors are classified as combined small-cell lung carcinoma (c-SCLC), and are (usually) treated as "pure" SCLC. Lung adenocarcinoma
Adenocarcinoma of the lung is currently the most common type of lung cancer in "never smokers" (lifelong nonsmokers). Adenocarcinomas account for about 40% of lung cancers.