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Lung Cancer

Overview


Our lungs are two spongy organs that are located in the chest cavity and allow us to breathe.


Lung cancer is a type of cancer that originates from lung tissues. Incidence of lung cancer is rising steadily worldwide and it is the second most common cancer type. Moreover, it is leading cause of cancer death in both men and women.


Risk Factors


Smoking is the most significant factor that causes the lung cancer and it is responsible for the great majority of the lung cancer cases.  Besides being active smoker, exposure to cigarette smoke in the environment (passive smoking) is also an important risk factor for the lung cancer. It is believed that cigarette smoke triggers the mechanism leading to lung cancer by both the carcinogenic substances and chemicals it contains and damaging the bronchial and alveolar walls. The probability of lung cancer due to smoking is related with both the number of cigarettes smoked and how long you have been an active smoker. It is also known that the probability of lung cancer decreases over time if smoking is quitted that causes or contributes onset of many extra conditions.


However, lung cancer may develop in individuals who have never smoked or have not been exposed to environmental cigarette smoke.


Among the known risk factors of lung cancer are exposure to asbestos and carcinogens as well as family history.


Types


Lung cancer has two major types; small cell lung cancer and non-small cell lung cancer. Mesothelioma and carcinoid tumor are rare cancers of lungs.


Symptoms


The early stage lung cancer usually does not cause symptom or it is manifested by non-specific symptoms that can frequently be seen in other diseases. These symptoms include:


    • Chronic cough
    • Blood in sputum (hemoptysis)
    • Shortness of breath
    • Wheezing
    • Changes in your voice or hoarseness
    • Unintended weight loss
    • Bone and joint pains,
    • Fluid accumulation in the chest


Prevention


As is the case for all other cancers, prevention of lung cancer is also to eliminate or minimize manageable risks.


    • Do not smoke or quit, if you smoke.
    • Do not allow people to smoke in your environment or do not stay anywhere smoking is allowed.
    • Toss all substances (radon, asbestos, etc) that are known to cause lung cancer out of your house and workplace.
    • Have healthy eating habits. Prefer a diet rich in fruits and vegetables
    • Exercise regularly, but take your general health condition into consideration.


Diagnosis


If the imaging studies (CT, MRI, PET) that are ordered to investigate findings suspicious for cancer show a mass, provisional diagnosis is made. The definitive diagnosis of the lung cancer requires taking a biopsy specimen. Biopsy specimen is taken by bronchoscopy or in a surgery.


After the diagnosis of lung cancer is made, the next step is to determine the stage. Your doctor will determine stage (I to IV) of your cancer based on a set of very strict criteria.  You may think that lung cancer is very broadly staged as local, limited or regional and distant.


Treatment


All data about patient and tumor are collected, the most appropriate treatment approach is determined. Treatment of lung cancer requires a rather though struggle. When possible treatment options are reviewed, it is necessary to weigh possible benefits against possible adverse effects and risks.


Although full recovery is the expected outcome for tumors that are confined to lung(s), treatment outcomes and survival rates may not be promising in cancers that have already spread to lymph nodes and/or distant tissues and organs.


One of the most important factors that determine the survival is the stage of the tumor at diagnosis. Unfortunately, most lung cancer cases are diagnosed at the late stages (II or IV). Therefore, the lung cancer is the leading cause of cancer death for both men and women worldwide.


Among the treatment options of the lung cancer are chemotherapy, targeted treatment, radiotherapy and surgery. These treatments can directly be used to treat the tumor or they are instituted to increase quality of life and relieve symptoms in advanced stage cancers. Moreover, treatment options can be used alone or in combination.


Chemotherapy


Chemotherapy uses drugs to treat the cancer. The active substances of drugs kill the cancerous cells. Chemotherapeutic agents can be given into a vein or be taken by mouth. In case of intravenous administration, a thin tube, called catheter, is inserted into a great vein and the chemotherapeutic agent is administered through this catheter throughout the treatment period.


One or more than one chemotherapeutic agent can be administered depending on the type of cancer and response to treatment. Active chemotherapy maintained for a particular time is followed by an “off” period. After the “off” period expires, the treatment resumes. Each of these sequential active and “off” periods is called a cycle.


In the early stage lung cancers, chemotherapy may be started before or after the surgery in order to both improve outcomes of surgery and enhance the survival rates.


In the advanced stage cancers and small cell lung cancers, the objective of the chemotherapy is to relieve symptoms, improve quality of life and extend the life as much as possible.


Side effects of the chemotherapy are a function of the chemotherapeutic agent and the dose. Most common side effects of chemotherapeutics include; fatigue, nausea, vomiting, mouth sores, hair loss and inflammation of the digestive system. Side effects caused by chemotherapy will also be treated by your doctor. If these side effects are severe enough to threaten your health, your doctor may advise to suspend the treatment or to switch you to another chemotherapeutic agent.


Targeted Therapy


Targeted therapies are newer anti-cancer treatments compared to chemotherapy. These medicines target specific abnormalities that are present in cancerous cells. Before these medicines are started, cancer cells are first analyzed in laboratories to determine whether they have particular mutations or not.


Radiotherapy


Radiation therapy aims to kill cancer cells by using high-powered energy beams.  


If the radiation source is out of the body and the beams are directed to cancer, this treatment is called external radiotherapy.  On the other hand, if the radioactive agent is placed at the locus of the tumor through a needle or a catheter, method is called internal radiotherapy (brachytheraphy).


Although radiation therapy can be the first-line treatment, it is usually used to kill cells that cannot be removed operatively. In the first-line treatment, radiotherapy is mostly combined with chemotherapy and this modality is also called chemoradiotherapy.  It plays an important role in relieving or eliminating pain, shortness of breath and chronic cough in advanced stage cancers.


If the lung tumor is very small in size, stereotactic radiotherapy (radiosurgery) may be useful in killing cancer cells by focusing radiation beams precisely on the tumor. In some cases, radiosurgery may remove the requirement for traditional surgery. However, patient selection is a very important issue for radiosurgery.


Radiotherapy has a very wide spectrum of side effects depending on the body part irradiated. Sore throat, difficulty swallowing, fatigue and loss of appetite are common side effects,you’re your doctor will explain the risks that apply to you.


Surgery

Surgery is the first-line treatment for early stage cases or tumors that are confined to the lung.


For lung resection, a segment, a lobe, two lobes or the whole lung can be resected or surgically removed and a wedge-like part of the lung is removed (wedge resection). Excluding wedge resection, all options are commonly referred to as anatomic resection.


Thoracotomy implies the open surgery carried out for lung resection. If technical means or patient and disease factors (location and spread of the condition) allow, minimally invasive surgery, videothoracoscopic surgery and robotic surgery are other options.


As thoracotomy offers the best exposure, a long incision is made at level of the fifth rib and lungs are exposed.


All lung resections are major surgeries and therefore, the patient should be very carefully prepped. Review of health history is followed by a comprehensive physical examination. Blood tests are planned in the light of signs and symptoms as well as physical examination data. Moreover, advanced imaging studies, such as CT, MRI and PET/CT, are ordered to visualize stage and spread of the condition and to plan the surgery.


Moreover, the patient is assessed by anesthesiologist in order to manage anesthesia-related risks and extra examinations are ordered, if required.


For lobectomy, the patient is transferred to the operating suite and an intravenous access line is inserted. A sedative agent is infused through this IV line to relax or calm down the patient. A tube is inserted to the throat of the patient in order to maintain breathing during the surgery. After anesthesia is administered, the patient is placed left lateral decubitus position, if the right lung is resected, or the patient is placed right lateral decubitus position, if the left lung is resected.


If open surgery (thoracotomy) will be carried out, an incision, measuring approximately 25 cm in length, is made at level of the 5th rib at the relevant side and lungs are exposed.


Small incisions are made for videothoracoscopic and robotic surgeries and ports are inserted through the incisions. While a camera is inserted through one of these ports, other ports serve insertion of surgical tools into the chest cavity.


After lobectomy, bilobectomy, pneumonectomy (removal of right or left lung completely) or wedge resection is carried out, two drains are placed, one in the apex of the lung and the other at the base. These drains function to drain fluid and blood and/or air that may accumulate in the body after the surgery.


Finally, the large or small incisions are stitched and closed with wound dressing.


Lobectomy – Bilobectomy: Lobectomy implies removal of a whole lobe of the lung due to a lung pathology or primary or metastatic cancer. As there are three lobes (upper, middle and lower lobes) are present in the right lung, bilobectomy refers concomitant removal of the middle lobe or lower or upper lobe. Thoracotomy is the open surgery method; however, if technical means or patient and disease factors (location and spread of the condition) allow, minimally invasive surgery, videothoracoscopic surgery and robotic surgery are other options. Thoracic surgeon determines the best method regarding the patient and the condition by reviewing all criteria.


Lobectomy is a major surgery and the artery that feed the lobe and the vein that drains the dark blood in the lobe are tied and cut/divided. Next, the bronchi of the lobe are similarly cut and the ends are closed. The lobe is dissected off the adjacent tissues and the nearby lobe.


A cavity develops in the chest cavity after lobectomy operations, but it is filled in as the rest lobe(s) will expand.


Segmentectomy: Lobes of lungs are divided into units, called segment. A lung segment is a lung unit with own artery, vein and bronchus. Ten segments are present in the right lung, while there are 8 segments in total in the left lung. Segmentectomy is the most minor one of the anatomic resections. The basic principle is to tie and cut the artery, the vein and the bronchus of the segment, occlude the end that is left inside the body and to dissect off and remove the segment completely.


Pneumonectomy:

Pneumonectomy refers to total removal of right or left lung. It is largely preferred for patients with lung cancer, who fulfill necessary criteria. In case of pneumonectomy, patients should be far more closely monitored and fluid intake and electrolytes should be very carefully monitored and managed.


Wedge resection: It implies anatomic resection of lungs. This method is preferred for lung biopsies or removal of lesions located at the periphery of lungs. The periphery of lungs is removed in the form of wedge or “V”.


Asking your questions about the treatment of lung cancer, your life after treatment, rehabilitation, pain management, clinical studies and all the questions in your mind about the lung cancer to your doctor will help you for an informed participation to your treatment and alleviating your concerns.