Lung

Pablo, Lung cancers make up 13% of all new cancers in the United States, as well as 28% of all cancer deaths. 1 The most common population in which lung cancers occur is in smokers over fifty years old. This falls in line with what we know of the effects smoking has on the lungs, as incidences of lung cancer continued to climb as smoking increased in popularity. || The risk for lung cancer is increased by the number of cigarettes smoked, the number of years spent inhaling, the tar and nicotine content of the specific cigarettes inhaled, and whether or not the cigarettes were filtered or not. 2 But, when smoking is cessated, the risk to the ex-smoker is decreased proportionally to the years without smoking. 2 Other etiologic factors include the exposure to asbestos, radon, bis (chloromethyl) ether, polyctic aromatic hydrocarbons, chromium, nickel, and organic arsenic compounds. 2 || The histology of lung cancers is divided into two different groups. 5 The thorax is an area of the body rich in lymphatics. One of the ways lung cancer can spread to other parts of the body is by using the lymphatic system. The following form the lymph node drainage of the lungs. The inferior lobes of both lungs drain into the superior and inferior tracheobronchial nodes, also known as the carinal nodes. The remaining lobes of each lung drain to the ipsilateral superior tracheobronchial lymph nodes. Eventually, all lymph from the lungs drain into the bronchomediastinal trunks. 6
 * **Epidemiolgy:** || Adam
 * **Etiology:** || Megan
 * **Signs & Symptoms:** || Kevin Tsai
 * Major symptom – Coughing (75% of patients and is severe in 40%)
 * Hemoptysis – 57% of patients
 * Common symptoms – Dyspnea and chest pains
 * Weight loss, weakness, anorexia, and malaise – 15% of patients
 * Pancoast’s or superior sulcus tumor syndrome – shoulder pain, brachial plexopathy, or Horner’s syndrome occur when tumors located in the apex of the lungs
 * Hoarseness – Involvement of the recurrent laryngeal nerve (more common with tumors of the left lung)
 * Involvement of the phrenic nerve can result in dyspnea and paralysis of the hemidiaphragm
 * Dysphagia may result from compression of the tumor on the esophagus
 * Superior vena cava syndrome – primary tumors located in the right lung or metastatic tumors in the right mediastinal lymph nodes
 * Secondary tumor effects (paraneoplastic syndromes) are sometimes seen 3 ||
 * **Diagnostic Procedures:** || Erin The following procedures and exams are done for diagnostic workup:
 * Chest x-ray – the most common exam for diagnostic workup 4
 * Computer tomography (CT) – valuable for evaluation, staging, and treatment planning (however, cannot differentiate between inflammatory disease and neoplasia)
 * Positron emission tomography (PET) – used to determine whether a lesion is malignant, to more accurately define tumor extent or lymph node involvement, and to aid in 3D treatment planning (3D-CRT)
 * Bronchoscopy examination – can aid in determining malignancy
 * Bone scan may be done if metastatic symptoms are present
 * A brain CT scan is frequently as part of the workup for small cell carcinoma
 * Pulmonary function tests – done prior to surgery or radiation ||
 * **Histology:** || Spencer
 * - Non-Small Cell Carcinoma **
 * Squamous Cell
 * Epidermoid
 * Large Cell Undifferentiated
 * Adenocarcinoma
 * Bronchoalveolar Carcinoma – Sometimes presents in Non-Smokers.
 * Carcinoid
 * - Small Cell Carcinoma (Oat Cell Cancer) ** ||
 * **Lymph node drainage:** || Pablo/Becky
 * Intrapulmonary lymph nodes: These are located inside the lungs themselves, either in the periphery of the lungs or in the hilar region forming what is called the hilar nodes
 * Mediastinal lymph nodes: Located in between the lungs, the mediastinum
 * Extrathoracic lymph nodes: These are located outside the thoracic cavity. They include the supraclavicular lymph nodes and the scalene lymph nodes. 6

|| Lung cancer can spread to different lymph nodes and organs throughout the body. Patterns of spread can be local, regional or distant. Metastasis also depends on the type of cancer that affects the individual. Small cell carcinomas tend to spread more than non-small cell carcinomas. 4 The grade of a tumor is based on its differentiation, and gives an indicator of how aggressive it is. While some cancers have their own grading systems, lung does not. 1
 * **Metastatic spread: ** || Pablo/Becky
 * Local metastases: Tumors can invade the mediastinum, upper middle and lower lobes of the lung, and the hillar lymph node. This is called intrathoracic metastases
 * Regional metastases: The supraclavicural nodes may also become involved, special the ipsilateral nodes.
 * Distant metastases: Distant organs of the body are usually involved in the later stages of the disease. Lung tumors tend to involve organs such as the liver, brain, bones, the adrenal glands and in some cases abdominal lymph nodes. 4 ||
 * **Grading:** || Adam

G1: Well-differentiated G2: Moderately-differentiated G3: Poorly differentiated G4: Anaplastic || Table taken from Chao 4 || Prognosis depends on tumor size, stage (extent of disease), histology, clinical performance status (KPS), and weight loss. 4 Studies have shown that patients with advanced intra-thoracic disease, extra-thoracic extension, a KPS score below 70, or weight loss greater than 5% rarely survive longer than 2 years regardless of therapy treatment. 7 Some genetic prognostic factors include mutations in the K-ras oncogene, deletion or tumor suppressor genes (p53 gene), and presence of N-cam expression. || There are a variety of different methods to treat lung cancer. **Radiation Therapy**: The use of radiation therapy can be used in many different forms throughout the patient’s treatment. Many of the factors associated with the treatment can depend on whether it is palliative or curative, and if the tumor is resectable or unresectable.1 Radiation therapy has been used for preoperative (although with not much improvement value), postoperative, and in combination with chemotherapy (usually the best treatment modality for patients with locally advanced medically inoperable tumors). This image showing a small lung nodule treated with radiation therapy. 8
 * **Staging:** || Megan
 * **Radiation side effects:** || Kevin Tsai
 * Acute
 * Esophagitis (third week), cough, skin reaction, and fatigue – during the course of irradiation or within 1 month after its completion1
 * Cough is common (second to bronchial mucosal irritation)
 * Lhermitte’s syndrome – 10% to 15% of patients
 * Late
 * Pneumonitis/pulmonary fibrosis, esophageal stricture, cardiac sequelae, spinal cord myelopathy (doses higher than 45 Gy in 1.8 to 2.0 Gy/fraction), and brachial plexopathy 3
 * Most reported sequelae in RTOG trails – Pneumonitis (10% grade 2 and 4.6% grade 3) and pulmonary fibrosis (approximately 20% grade 2 and 8% grad 3 or greater)
 * Threshold dose for radiation pneumonitis is 20 to 22 Gy
 * Long-term esophageal problems such as stenosis, ulceration, perforation, and fistula formation are seen in 5% to 15% of patients ||
 * **Prognosis:** || Erin Prognosis
 * **Treatments:** || Spencer

<span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif;">**Chemotherapy**: The use of chemotherapy is widely used for any form of lung cancer. Whether the lung cancer is resectable, unresectable, pre-operative and post-operative, the use of cisplatin based chemotherapeutic agents improve overall survival.

Side effects of lung cancer irradiation are divided into two groups. Acute, which occur during and up to 3 month of the start of treatment and chronic, which are noticeable 3 months after the start of treatment. 9 The following organs are to be considered when planning a lung radiation treatment. || Back to Week 3
 * <span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif;">Brachytherapy **<span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif;">: Not widely used as often, brachytherapy can be used as an alternative treatment for localized unresectable tumors. This method can be used in addition to external beam radiation therapy, or as a boost to push more dose towards the tumor volume. <span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif; vertical-align: super;">5 ||
 * **TD 5/5:** || PabloTD 5/5
 * **References:** || Becky
 * CM, Leaver D. Principles and Practice of Radiation Therapy. 2nd ed. St. Louis, MO: Mosby Inc; 2004.
 * 1) Lenards, N. Lung. [PowerPoint]. La Crosse, WI: UW-L Medical Dosimetry Program; 2013.
 * 2) Chao C, Perez C, Brady L. Radiation Oncology Management Decisions. 3rd ed. PA: Lippincott Williams and Wilkins; 2011:327-339.
 * 3) Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002. P303-319.
 * 4) Chao, K, Perez, C, Brady, L. Radiation Oncology Management Decisions. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002.
 * 5) Basic Human Anatomy. Website. [|http://www.dartmouth.edu/~humananatomy/part_4/chapter_24.html. Accessed Jun 12], 2013.
 * 6) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. St. Louis, MO: Mosby Inc; 2010:666-667.
 * 7) Radiographics. Radiographics Web Site. http://radiographics.rsna.org/content/31/3/771/F16.expansion.html. Accessed June 10, 2013.
 * 8) About Cancer. Web site. []. Accessed Jun 8, 2013. ||