Lung

There are many occupational exposure risks that have been linked to lung cancer including coal tar fumes, nickel, chromium, and arsenic. Dealing with radioactive isotopes can increase your risk factor mainly those that produce alpha particles in their decay process such as radon and uranium. Genetic and environmental factors may increase the risk factors of exposure. 8 ||
 * **Epidemiolgy:** || Around 1.35 million new cases of lung cancer present every year. Lung cancer is the leading cause of cancer death in the United States. 7 ||
 * **Etiology:** || Smoking greater than one pack a day is the most significant contributor to lung cancer. Increasing the number of cigarettes smoked per day, a longer smoking history, as well as smoking unfiltered cigarettes may all increase the incidence of lung cancer in an individual. Second hand smoke has also been linked to the development of lung cancer.
 * **Signs & Symptoms:** || In many cases the signs and symptoms of lung cancer are hard to differentiate from those of chronic obstructive pulmonary disease. These signs and symptoms are separated into three different categories.

Local disease: usually the earliest symptoms, they include a cough that can be unremitting. In many cases blood may accompany this cough and is usually the first sign on disease. A small percentage of patients complain of shortness of breath and chest pain during this stage.

Regional disease: usually includes extension into the central Mediastinal, paratrachel, parahilar, and subcarinal lymph nodes. Pain, coughing, dyspena, and in some cases the formation of an abscess may all accompany this stage. Esophageal compression may result from Mediastinal involvement causing dysphagia. Superior vena cava syndrome (SVC) a condition, most common in lesions of the right lobe extending into the mediastinum, where the tumor puts pressure on the superior vena cava. This pressure can result in the inability to lie flat, swelling of the face neck and arm, cyanosis, and difficulty breathing. This condition will present during the regional phase.

Metastatic disease: most common symptoms during this phase are loss of appetite, fatigue, and weight loss. During this phase of the disease a very small percentage of patients may experience paraneoplatic syndrome, which is when chemicals produced by the lesion itself can cause nerve muscle and endocrine gland complications. || * Non Small Cell Lung Cancer (NSCLC) Table 1 || Mediastinal and intrapulmonic  Table1 || Local (intrathoracic) spread: Regional (lymphatic) spread: Distant (hematogenous) spread: Squamous cell carcinoma has the greatest tendency to remain confined to the thorax. Small cell cancers (particularly adenocarcinoma) have a higher incidence of distant metastases. 3 || Grade: GX Grade cannot be assessed (Undetermined grade) G1 Well-differentiated (Low grade) G2 Moderately differentiated (Intermediate grade) G3 Poorly differentiated (High grade) G4 Undifferentiated (High grade) || TX: Tumor cannot be evaluated or tumor is proven by the presence of cancer cells in the sputum or bronchial washings, but it cannot be seen during imaging or bronchoscopy ("occult" tumor) T0: No evidence of primary tumor Tis: Carcinoma in situ T1: Tumor 3 centimeters (< 3 cm) or less in greatest dimension, surrounded by lung or pleura, and not located in the main stem bronchus. T2: Tumor more than 3 centimeters (> 3 cm) in greatest dimension, or tumor involving the main stem bronchus, 2 cm or more from the carina, or tumor invading the visceral pleura, or tumor with incomplete lung expansion or obstructive lung infection that does not involve the entire lung. T3: Tumor of any size that directly invades the chest wall, diaphragm, pleura, or pericardium, or tumor that involves the main stem bronchus less than 2 centimeters (< 2 cm) from the carina (ridge between the right and left main stem bronchi), or tumor that is associated with complete lung collapse or obstructive lung infection involving the entire lung. T4: Tumor of any size that invades the heart, great vessels (aorta, superior or inferior vena cava, pulmonary artery, or pulmonary vein), trachea, esophagus, vertebral body, or carina, or separate tumor nodules in the same lung lobe, or tumor associated with a malignant pleural effusion. **Lymph nodes (N**) NX: Regional lymph nodes cannot be assessed N0: Regional lymph nodes contain no metastases N1: Metastasis to same-side peribronchial (around the bronchi) and/or hilar (pit in the lungs where vessels enter and exit) lymph nodes and nodes within the lungs that are involved by direct spread of the primary tumor N2: Metastasis to same-side mediastinal and/or subcarinal (under the carina, or tracheal ridge) lymph nodes N3: Metastasis to opposite-side mediastinal or hilar nodes or to same- or opposite-side scalene (neck/upper rib) or supracalvicular (above collarbone) lymph nodes. MX: Distant metastases cannot be assessed M0: No distant metastases are found M1: Distant metastases are present (this also includes separate tumor nodules in a different lobe of lung on either side). STAGING ||< || || **Resectable NSCLC** 6 **Inoperable NSCLC** 6 **SCLC** 6
 * **Diagnostic Procedures:** || * Routine chest X-Ray—most common examination 1
 * Computed Tomography (CT) scans can be used, and is a valuable study for evaluation, staging and therapeutic planning if lung cancer. 1
 * Cannot differentiate between inflammatory disease from neoplasia
 * PET (positron emission tomography) can be used to determine whether lesions are malignant and to identify the extent of the tumore. 1
 * Increased sensitivity and specificity for staging when PET scans are used with CT scans ||
 * **Histology:** || The World Health Organization (WHO) has classified 12 different primary tumor types within lung cancer. These are more efficiently distributed into the more recognized categories: 2
 * Adenocarcinoma, large cell carcinoma and epidermoid (squamous cell)
 * Small Cell Lung Cancer (SCLC)
 * Anaplastic carcinomas
 * Mesothelioma
 * Less frequent
 * **Lymph node drainage:** || Primary lymphatics that drain the lungs include: 2
 * **Metastatic spread:** || The lung has a rich network of lymphatics, as well as bronchial and pulmonary vessels. This stands for high frequency of mediastinal lymph node and blood vessel metastatic involvement. The pattern of spread may be local (intrathoracic), regional (lymphatic), or distant (hematogenous).
 * Apical tumors involve cervical and thoracic nerves, resulting in Pancoast’s or superior sulcus tumor syndrome.
 * Metastatic tumors in the right mediastinal lymph nodes may cause superior vena cava syndrome.
 * Brain
 * Bone
 * Adrenal glands
 * Liver
 * **Grading:** || The American Joint Commission on Cancer recommends the following guidelines for grading tumors: 4
 * **Staging:** || ** Primary Tumor (T) **
 * Distant metastasis (M) **
 * Stage Ia: || T1, N0, M0 ||
 * Stage Ib: || T2, N0, M0 ||
 * Stage IIa: || N1, M0 ||
 * Stage IIb: || T2, N1, M0 or T3, N0, M0 ||
 * Stage IIIa: || T1-2, N2, M0 or T3, N1-2, M0 ||
 * Stage IIIb: || T(any), N3, M0 or T4, N(any), M0 ||
 * Stage IV: || T(any), N(any), M1 ||  ||
 * **Radiation side effects:** || Acute side effects of radiation therapy include dermatitis, mild to chronic esophagitis, as well as cough. Radiation-induced lung disease (RILD) can present in the form on radiation pneumonitis (RP), which is similar to bacterial pneumonia. Symptoms include cough, dyspnea, chest pain, malaise, and fever. Late RILD comes in the form of radiation induced-induced fibrosis (RIF). Symptoms include chronic dyspnea and even respiratory failure. 6 ||
 * **Prognosis:** || ** Patient-specific Prognostic Factors ** 5
 * Performance status (Karnofksy score)
 * Extent of disease
 * Weight loss
 * Tumor-specific Pragnostic Factors ** 5
 * Tumor size
 * Histologic grade
 * Treatment-specific Prognostic Factors ** 5
 * Resectable patients
 * Surgical stage
 * Completeness of resection
 * Inoperable patients
 * Weight loss
 * Karnofsky performance status
 * Age
 * Gender
 * Dyspnea
 * Hoarsness
 * Histology
 * Stage
 * Normal protein, hemoglobin, blood urea nitrogen, and lactate dehydrogenase
 * Tumor location
 * Molecular Prognostic Factors ** 5
 * Gene mutations ||
 * **Treatments:** || The two primary types of lung cancer are non-small cell lung cancer (NSCLC), and small cell lung cancer (SCLC). Treatment for lung cancer is determined by the type of cancer, and whether or not it is able to be surgically resected. 6
 * Preoperative Radiation Therapy
 * Postoperative Radiation Therapy
 * Preoperative Chemotherapy
 * Adjuvant Chemotherapy
 * Preoperative Chemoradiotherapy
 * Radical Radiation Therapy for Inoperable Early-Stage NSCLC
 * Radical Radiation Therapy for Locally Advanced NSCLC
 * Radiation Therapy Alone
 * Sequential Chemotherapy and Radiation
 * Concurrent Chemoradiation
 * Surgery normally not an option
 * Concurrent Chemoradiation
 * Prophylactic Cranial Irradiation (in case of brain metastasis)

**Radiation Therapy Techniques** 5 Image courtesy of: Nocolaou N. Prevention and Management of Radiation Toxicity. In: Pazdur R, Coia LR, Hoskins WJ, Wagman LD, eds. Cancer Management: A Multidisciplinary approach [e-book]. 10th ed. CMPMedica; 2007. Available from: CancerNetwork. Accessed June 4, 2012. ||
 * Traditional Portals
 * 2 cm margin around GTV
 * 1 cm margin around electively treated lymph nodes
 * Ipsilateral supraclavicular region included in upper lobe portals
 * Inferior margin 5 to 6 cm below carina
 * No need to treat supraclavicular regions in middle or lower lobe with no lymphadenopathy present
 * Ipsilateral hilum is typically included, and contralateral hilum is not
 * Three-Dimensional Conformal Radiation Therapy (3DCRT)
 * Different portals, target volumes, and beam arrangements due normal tissue sparing
 * Optional brachytherapy ||
 * **TD 5/5:** || TD 5/5 for one-third, two-thrids, and three-thirds lung is 45, 30, and 17.5 Gy, respectively. 5
 * **References:** || # Stinson D, Wallner PE. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, Missouri; Mosby Inc: 669-676.
 * 1) Chao KC, Perez CA, Brady LW. //Radiation Oncology Management Decisions.// 3rd ed. Philadelphia, PA; Lippincott Williams & Wilkins. 2011: 327-330.
 * 2) Chao KC, Perez CA, Brady LW. //Radiation Oncology Management Decisions.// 3rd ed. Philadelphia, PA; Lippincott Williams & Wilkins. 2011:305-320.
 * 3) MedicineNet. Tumor grade. Available at: []. Accessed June 5, 2012.
 * 4) Perez CA, Brady LA, Halpern EC, Schmidt-Ullrich RK. Principles and Practice of Radiation Oncology. 4th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2004.
 * 5) Hoppe RT, Phillips TL, Mack III M. Leibel and Phillips Textbook of Radiation Oncology. 3rd ed. Philadelphia Pa: Elsevier Saunders; 2010. ||

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