What is Small Cell Lung Cancer?
Small cell lung cancer is the tumor that spreads more quickly through the lung. Also called small cell lung carcinoma, it can be divided between small cell carcinoma and small cell carcinoma combined.
Approximately 15% of all lung cancer cases are small cell, being more common in men than women. It is the most aggressive form of lung cancer, usually starting in the bronchi and with high potential to create metastases in other parts of the body, such as brain, liver and bone. Almost all cases of small cell lung cancer are due to smoking.
Small cell lung cancer may be of the metastatic type, ie be a consequence of a primary tumor in other organs such as bladder or breast.
There are two main types of lung cancer: non-small cell and small cell. While non-small cell lung cancer develops in epithelial cells, small cell lung cancer reaches the central airways.
However, it is important to note that not all small cell lung cancers are the same. Within this category there are several different characteristics that are not based exclusively on the size and shape of the cells. During the last few years it has become clear that this classification is not sufficient to understand the different biology of all lung cancers, since tumors of similar appearances have different biological characteristics.
Small Cell Lung Carcinoma
There are two main types of small cell lung cancer: small cell carcinoma and small cell carcinoma combined. This classification is made according to the appearance of tumor cells under a microscope and how they are found.
The most common cause of lung cancer is smoking for a long period of time. Most deaths from small cell lung cancer are caused by smoking or exposure to second-hand smoke.
In addition to cigarette smoking, it is clear that the smoker is at increased risk for lung cancer when exposed to other factors such as:
- Hereditary genetic disorders
- Inhalation of chemical agents such as asbestos, radon, asbestos and arsenic
- Inhalation of dust and air pollution
- Passive smoking
- Some diseases also predispose to malignancy, such as tuberculosis and chronic obstructive pulmonary disease (COPD).
Non-Smoking Lung Cancer
It is rare for anyone who has ever smoked to be diagnosed with small cell lung cancer, but it can happen. Lung cancer in non-smokers can be caused by exposure to substances such as radon, second-hand smoke, air pollution or other substances.
A small portion of lung cancer cases occur in people with no known risk factors for the disease. Some of them may be just random events that do not have an external cause, but others may be due to factors that we still do not know about.
The incidence of lung cancer is highly correlated with cigarette smoking. About 90% of lung cancer cases arise as a result of smoking. The risk of lung cancer increases with the number of cigarettes smoked over time.
The cigarette contains more than 4,000 chemical compounds, many of them proven to be carcinogenic. The two primary carcinogens of tobacco are nitrosamines and polycyclic aromatic hydrocarbons. They will influence the mutation of the lung cells, which can begin to divide uncontrollably, resulting in cancer.
In addition to cigarettes, smoking pipes, cigars and other types of tobacco can cause small cell lung cancer, although the risk is not as high. While someone who smokes a pack of cigarettes a day has a 25-fold higher risk of lung cancer than a non-smoker, people who smoke pipe and cigar smokers have a lung cancer risk about five times greater than one.
The risk of developing small cell lung cancer declines each year after cessation of smoking, as normal cells grow and replace damaged cells in the lung. In former smokers, the risk of developing lung cancer begins to approach that of a non-smoker about 15 years after cessation of smoking.
Passive smoking is also an established risk factor for the development of lung cancer. According to data at the National Cancer Institute (INCA) adults who are exposed to second-hand smoke have a 30% higher risk of developing lung cancer than non-smokers who do not expose themselves.
Other risk factors:
It is known that smoking is the main risk factor for small cell lung cancer. However, there are other lifestyle habits and factors that can influence this risk, albeit more discreetly. See what they are:
- Exposure to asbestos: Asbestos fibers are silicate fibers that can persist for life in the lung tissue after exposure. The workplace is a common source of exposure to asbestos fibers, which has been widely used in the past for the manufacture of thermal and acoustic insulation materials. Today, the use of asbestos is limited or prohibited in many countries. Lung cancer is related to asbestos exposure, and the risk increases dramatically if one also cultivates smoking habits
- Family history: The fact that not all smokers develop lung cancer suggests that other factors, such as individual genetic susceptibility, may play a role in the cause of lung cancer. Numerous studies have shown that lung cancer is more likely in people with lung cancer cases in the family than in the general population. However, further studies are needed to state which genes may be related to this predisposition
- Pulmonary disease: The presence of certain lung diseases, such as COPD, is associated with a slightly increased risk for lung cancer, even after the effects of smoking are excluded
- Previous history of lung cancer: lung cancer survivors have a greater risk than the general population of developing a second lung cancer. Those who have had non-small cell lung cancer have an additive risk of 1 to 2% per year for the development of a second lung cancer
- Pollution: Air pollution from vehicles, industries and power plants can increase the likelihood of developing lung cancer in exposed individuals. Up to 1% of lung cancer deaths are attributable to breathing polluted air, and experts believe that prolonged exposure to heavily polluted air can carry a similar risk to passive smoking for the development of small cell lung cancer.
Symptoms of Small Cell Lung Cancer
Most symptoms of small cell lung cancer take time to manifest. When the patient notices some discomfort, in many cases the tumor has already spread and may have metastasized. The main symptoms are:
- Chest pain
- Loss of appetite and weight
- Shortness of breath
- Cough with mucus expectoration
- Coughing up blood
- Recurrent infections.
Seeking medical help
Any of the manifestations of symptoms, especially if known exposure to risk factors, should serve as an alert for the search for medical advice. Characteristic changes in cough, such as increased frequency and phlegm production, are indicative of seeking a doctor.
In some patients who do not have signs and symptoms, small cell lung cancer can be detected by chest X-ray or CT scan. However, most people with lung cancer are diagnosed when the tumor grows or begins to interfere with other organs and / or tissues.
At the medical appointment
Experts who can diagnose small cell lung cancer are:
- Thoracic Surgeons.
Being prepared for the appointment can facilitate diagnosis and optimize time. That way, you can already get the query with some information:
- A list with all the symptoms and how long they appeared
- Medical history, including other conditions the patient has, and medications or supplements that he or she takes regularly
- If possible, ask a person to accompany you.
The doctor will probably ask a series of questions, such as:
- When did the symptoms start?
- Are the symptoms continuous or occasional?
- How severe are your symptoms?
- You smoke? How long?
- Do you feel a wheezing sound?
- Do you have a cough that looks like it is clearing your throat?
- Have you ever been diagnosed with emphysema or COPD?
- Do you take medicine for shortness of breath?
- What, or something, seems to improve your symptoms?
- What, or something, seems to make your symptoms worse?
It is also important to take your questions to the written consultation, starting with the most important. This ensures that you will get answers to all relevant questions before the consultation is over. For small cell lung cancer, some basic questions include:
- What is causing my symptoms?
- What exams do I need to do? Should I see a specialist?
- Are there any publications or other material that I can take with me? Which sites do you recommend?.
Do not hesitate to ask further questions if they occur at the time of the consultation.
Diagnosis of Small Cell Lung Cancer
In some patients who do not have signs and symptoms, lung cancer can be detected by chest X-ray or computerized tomography. However, most people with lung cancer are diagnosed when the tumor grows or begins to interfere with other organs and / or tissues.
Although cancer can spread to any part of the body, the most common sites are lymph nodes, lungs, bones, brain, liver, and adrenal glands. Metastases can cause respiratory discomfort, bone pain, weakness, abdominal pain, back pain, headache, seizures, neurological changes, jaundice, or swelling.
There are several important tests to be evaluated for small cell lung cancer at the time of diagnosis and follow-up. The main ones are:
- Bone scintigraphy
- Chest computed tomography
- Chest X-ray
- Cytological studies of pleural fluid or saliva
- Pulmonary needle biopsy
- Pulmonary surgical biopsy.
Among these exams, the most important are computed tomography and bone scintigraphy. An important tool has recently been used in some cases, which is the examination called positron emission tomography (PET-CT). This is an equipment that unites the diagnostic resources of Nuclear Medicine (PET) and Radiology (CT). The equipment overlies the metabolic images (PET) to the anatomical images (CT), thus producing a third type of image. It can aid in early diagnosis, assess the extent of disease, the effectiveness of a treatment, as well as in the planning of radiotherapy. In some cases, one can even avoid invasive procedures.
Talk to your doctor
After receiving a diagnosis of small cell lung cancer, you may want to ask the doctor several questions. Being informed about your condition helps you better understand the problem and get the best treatments for you:
- What type of lung cancer do I have?
- What is the stage of my lung cancer?
- Can I see a chest x-ray or CT scan, which shows my cancer?
- Has my cancer spread to other parts of the body?
- What are my treatment options?
- Can any of these treatments cure my cancer?
- What are the side effects of each treatment?
- Is there a treatment that you think is best for me?
- Is there a benefit if I quit smoking now?
- What if I do not want the treatment?
- Are there ways to alleviate the signs and symptoms that I am experiencing?
- Can I enroll in a clinical trial ?.
Treatment of Small Cell Lung Cancer
The main forms available are surgery, radiotherapy, chemotherapy, and other palliative methods. They can be used individually or in combination, depending on the type of tumor and level of progression. Treatment options should be discussed with the medical team that will set the best option for each agency.
Chemotherapy uses drugs that prevent the growth of cancer cells or kill existing cells by stopping cell division. Chemotherapy can be given orally or injected into the vein or muscle.
Drugs enter the bloodstream and can reach cancer cells throughout the body, in a process called systemic chemotherapy. When chemotherapy is placed directly into the spine, organ, or body cavity (such as the abdomen), the drugs primarily affect the cancer cells in those areas – in the treatment known as regional chemotherapy. How chemotherapy is administered depends on the type and stage of the cancer being treated.
Chemotherapy for small cell lung cancer is usually given as a combination of two drugs. The combinations most often used to treat small cell lung cancer are:
- Cisplatin and etoposide
- Carboplatin and etoposide
- Cisplatin and irinotecan
- Carboplatin and irinotecan.
Radiation therapy is a treatment that uses high energy x-rays or other types of radiation to kill cancer cells. The most commonly used type for small cell lung cancer is external radiation therapy, which uses a machine out of the body to send radiation to cancer.
In addition, radiosurgery is a method of administering radiation directly into the tumor, with little damage to healthy tissue. It does not involve a surgical procedure and can be used to treat certain tumors in patients who can not perform the surgery.
How radiation therapy is administered depends on the type and stage of the cancer being treated. The type of radiation therapy most often used to treat small cell lung cancer (CPPC) is called external radiation therapy (RT). It provides radiation from outside the body and it focuses on cancer.
Radiation can be used to shrink tumors and relieve symptoms of lung cancer such as bleeding, difficulty swallowing, coughing, shortness of breath, bone pain and problems caused by metastases.
Four types of surgery are used:
- Wedge resection: Also called a segmentectomy, wedge resection consists of the surgical procedure to remove a triangle-shaped slice of lung tissue. The segmentectomy is used to remove a tumor and a small amount of normal tissue around it. When a slightly larger amount of tissue is removed, it is called a segmental resection
- Glove resection: surgery to remove part of the bronchus
- Lobectomy: surgery to remove an entire lobe of the lung
- Pneumonectomy: the surgical procedure to remove an entire lung. This treatment is used only in very advanced cases.
In addition to conventional ways of combating small cell lung cancer, other approaches may be used. Look:
- Laser therapy: Laser therapy is a cancer treatment that uses a laser beam (a narrow beam of intense light) to kill the cancer cells. The indication of the laser and how the procedure is done depends on the type and stage of small cell cancer
- Photodynamic therapy: It is sometimes used to treat small cell lung cancer at very much stage. It can also be used to help open the airways blocked by tumors to help people breathe better. For this technique, a drug called porfimer sodium is injected into the vein and accumulates in cancer cells within a few days. Then a bronchoscope is inserted into the lung under local or general anesthesia. A special laser light placed at the end of the bronchoscope is directed at the tumor, activating the drug that destroys the cancer cells. This means that although the drug is there and spread through the cells, it will only take effect when exposed to light. Once the tumor cells are deadly, they are removed during bronchoscopy. Photodynamic therapy can cause inflammation in the airway for a few days, causing shortness of breath, coughing up blood or thick mucus.
If the treatment stops responding
For rare or very advanced cases, conventional therapies may no longer work. Even if cancer cannot be cured, one should avoid as much as possible any symptom of the disease. If curative treatment is not an option, treatment is intended to alleviate the symptoms and even slow the spread of the disease.
The decision on the right time to discontinue treatment and focus only on symptom relief should be made by the patient in conjunction with his or her medical staff. Although not an easy decision, communication with doctors, nurses, family members, and friends can help.
Living together / Prognosis
Smoking is related to more than 90% of cancer cases. That way, stopping smoking should be the first step for a person who has small cell lung cancer. Complex diseases such as lung cancer require the follow-up of a multidisciplinary team. Physicians, physiotherapists, dentists, psychologists, and occupational therapists are part of this team.
Following your guidelines and correctly using the prescribed support treatments are critical to successful oncology therapy. Maintaining a balanced diet, proper water intake and physical activity, as well as a proactive and optimistic attitude along the way, are key.
Possible complications arise from the size, site of the lesion, and eventually substances produced by the tumor and released into the bloodstream. Its growth can affect by invasion, obstruction or compression of respiratory, vascular or nervous structures. There is always the potential for bleeding, and symptoms may occur as a result of elements secreted by the tumor or the sites of metastasis.
If small cell lung cancer advances through the organ, a liquid may appear in the pleural cavity, occupying the entire lung and causing respiratory failure. If you advance to the heart, it may decrease the functionality of this as well as cause liver failure if it picks up the liver. Lung cancer can also progress to the central nervous system or spine, which can cause paralysis, injury and impaired movement.
When lung cancer spreads to distant organs (metastasis), it can cause:
- Bone pain (such as back pain or hips)
- Neurological changes (such as headache, weakness or numbness of an arm or leg, dizziness, balance problems, or seizures)
- Yellowing of the skin and eyes (jaundice)
- Protrusions near the surface of the body.
If you suffer from small cell lung cancer and have any of these problems, it is important to see your doctor immediately so that the cause is detected and treated if necessary.
Small Cell Lung Cancer Has Cure?
The 5-year survival rate refers to the percentage of patients living at least 5 years after the diagnosis of cancer. For small cell lung cancer, it is estimated that 31% of people diagnosed at an early stage have a 5-year survival rate, while 8-2% of people diagnosed at more advanced stages with metastases can achieve this goal.
Survival rates are often based on previous results of a large number of people who have had the disease, but one can not predict what will happen with each case. Many other factors can also affect a person’s perspective, such as general health, treatment received, and how cancer responds to treatment. Your doctor can tell you how the numbers apply to you.
Avoiding risk factors and increasing protective factors may help prevent small cell lung cancer.
Smoking is the most important risk factor for small cell lung cancer. Cigarette, cigar, pipe and other forms of tobacco use may increase the risk of lung cancer. Smoking causes about 9 out of 10 lung cancer cases in men and about 8 out of 10 lung cancer cases in women.
The risk of lung cancer is also related to the number of cigarettes smoked per day and the time of addiction – so the more cigarettes you smoke per day and the earlier you start, the greater the risk. People who smoke have about 20 times the risk of lung cancer compared to those who do not smoke.
Avoid second-hand smoke
Being exposed to tobacco smoke is also a risk factor for small cell lung cancer. Second-hand smoke is smoke that comes from a lighted cigarette or other tobacco product or is exhaled by smokers. People who inhale second-hand smoke are exposed to the same cancer-causing agents, albeit in smaller amounts.
Beta-carotene supplements in heavy smokers
This nutrient is present in several foods, especially in those that colour orange, such as carrots. However, supplementation of beta-carotene in smokers may reduce the risk of lung cancer, especially in those who smoke one or more packs per day.
- Artur Katz, oncologist and coordinator of clinical oncology at the Oncology Center of the Sírio-Libanês Hospital
- Junia Thirzah Gehrke, oncologist at the Cancer Institute of Brasília (CRM DF 20039)
- USA National Cancer Institute
- American Cancer Society
- World Health Organization.