Lung cancer is a disease that causes cells to divide in the lungs uncontrollably. This results in the growth of tumor that reduce a person’s ability to breathe. Lungs are two spongy organs located in the chest that take in oxygen when you inhale and release carbon dioxide when you exhale. It is the main cause of cancer death globally.
Human beings who smoke have the greatest risk of lung cancer, though it can also occur in people who have never smoked. The risk increases with the length of time and the number of cigarettes you have smoked. If you quit smoking, even after many years of doing it, you can significantly decrease your chances of developing lung cancer.
Types of lung cancer
The two types of lung cancer are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Important point to note is that NSCLC accounts for mostly nine out of every 10 diagnoses and typically grows at a slower rate than SCLC.
- Non-small cell lung cancer – The three main types are:
- Squamous cell – It is found centrally in the lung, where the larger bronchi join in one of the main airway branches or to the trachea to the lung. It is responsible for about 30 per cent of all NSCLC and is usually linked to smoking.
- Adenocarcinoma of the lung – It is the most common form of lung cancer, accounting for about 40 per cent of all NSCLC. It is found in several common cancers, including prostate, breast and colorectal. Adenocarcinomas are found in the outer region of the lung, and in glands that secrete mucus which help us breathe
- Large-cell undifferentiated carcinoma – This lung cancer spreads and grows quickly and can be found anywhere in the lung. It usually accounts for 10 to 15 per cent of all cases of NSCLC.
- Small cell lung cancer – It is known as ‘oat-cell’ cancer because the cells look like oats under a microscope. The cancer often starts in the bronchi and then quickly grows and spread to other parts, including the lymph nodes. It represents less than 20 per cent of lung cancers and is typically caused by tobacco smoking. It is divided into two types, named for the kinds of cells found in cancer and how they look when viewed under a microscope:
- Combined small cell carcinoma
- Small cell carcinoma (oat-cell cancer)
Lung cancer generally does not show any symptoms and signs in the beginning. It typically occurs when the disease is advanced. Some of them include:
- Shortness of breath
- Chest pain
- Losing weight
- Bone pain
- A new cough that does not go away
- Coughing blood, even a small amount
Causes and diagnosis of lung cancer
90% of lung cancer cases are the result of smoking. The moment you inhale smoke into the lungs, it starts damaging the lung tissue. The lungs can repair the damage, however continued exposure to smoke makes it difficult for the lungs to keep up with the repair. After the cells are damaged, they begin to behave abnormally which increases the likelihood of developing cancer. Small-cell lung cancer is mostly associated with heavy smoking.
The second leading cause of lung cancer is exposure to radon, a naturally existing radioactive gas. It enters buildings through little cracks in the foundations. Smokers who are exposed to radon develop a very high risk of lung cancer. Breathing in other hazardous substances, mostly over a long period of time, can also result in lung cancer. Other substances that can cause lung cancer are nickel, uranium, cadmium, arsenic, some petroleum products, etc.
The doctor might do imaging tests that may help diagnose lung cancer. Imaging tests form pictures of the inside of your body. The pictures help doctors to find lung cancer, to determine if it has spread, to see if treatment is working or to find a cancer that has come back after the treatment. The tests include:
- CT scan
- PET scan (Positron emission tomography)
- Bone scan
To figure if something suspicious is actually bone cancer, the doctor must study fluid or tissue from or around the lung. A lot of procedures allow doctors to remove cells from the body and study them under a microscope to determine if they are cancer. Some of these tests include:
- EBUS (Endobronchial ultrasound)
- Bronchoscopy biopsy
- EUS (Endoscopic esophageal ultrasound)
- Mediastinoscopy and mediastinotomy
- Sputum cytology
- Open biopsy
Stages and treatment options
The chance of a curative treatment is much higher when lung cancer is detected and treated in the early stages, before it grows. Since lung cancer does not cause obvious symptoms in the beginning, diagnosis often comes after it has spread. NSCLC contains four main stages:
- Stage 1 – Cancer is found in the lung but it has not spread outside of that.
- Stage 2 – Cancer is found in the nearby lymph nodes and lung
- Stage 3 – Cancer is in the lymph nodes and lung in the middle of the chest
- Stage 3A – Cancer is found in lymph nodes but on the same side of the chest where cancer first started developing.
- Stage 3B – Cancer has spread to lymph nodes above the collarbone or on the opposite side of the chest.
- Stage 4 – Cancer has spread to both lungs, into the areas around the lungs or to the distant organs.
On the other hand, SCLC has two main stages. In the limited stage cancer is found in only one lung or the nearby lymph nodes on the same side of the chest. Whereas the extensive stage means cancer has spread:
- to the opposite lung
- throughout one lung
- to fluid around the lung
- to lymph nodes on the opposite side
- to distant organs
- to bone marrow
An important point to note is by the time of diagnosis, 2 out of 3 people with SCLC are already in the extensive stage.
Lung cancer can be treated in several ways, depending on the type of cancer and how much it has spread. People with NSCLC can be treated with chemotherapy, surgery, radiation therapy, targeted therapy or a combination of these treatments. People with SCLC are mostly treated with chemotherapy and radiation therapy.
- Surgery – An operation where doctor cuts out the cancer tissue.
- Chemotherapy – Using special medicines to kill or shrink cancer.
- Surgery – An operation where doctor cuts out the cancer tissue.
- Radiation therapy – Using high energy rays which are similar to x-rays to kill the cancer.
- Targeted therapy – Using drugs to block the spread and growth of cancer cells.
A team of specialists is responsible for coming together and treating lung cancer. While medical oncologists are doctors who specialize in treating cancer, radiation oncologists specialize in using radiation to treat cancer. Pulmonologists focus on the lung diseases and thoracic surgeons operate on the chest. Last but not the least palliative care specialists treat symptoms and signs of cancer and its treatment.
Side effects of treatment
Some of the common side effects include:
- Breathing problems
- Bleeding, infection and anemia (chemotherapy can lower the blood count)
- Changes in appearance, including hair loss
- Stomach problems (vomiting, nausea, diarrhea or constipation)
- Effects on fertility and changes in sexual functioning
- Pain and discomfort
Some serious side effects of chemotherapy may include lowered white blood cell count, which increases problems with heart function and the risk of infection. It is always advisable to consult a doctor in case you face any heart problems.
Survivorship and prevention for lung cancer
For some people with lung cancer, treatment may destroy or remove the cancer. For others, lung cancer may never go away completely. Some people may get regular treatments like radiation therapy, chemotherapy and other therapies to try to control it for as long as possible. Learning to live with cancer that does not go away can be stressful and difficult.
- Follow-up care ─ If you have completed treatment, the doctors will still want to observe you closely. It is very important to go to all of your follow-up appointments. It is also important to let you doctor know about any new symptoms because it could be a sign of cancer coming back.
- Getting emotional support ─ It is normal to feel anxious, depressed, or worried when small cell lung cancer is part of your life. Few people are affected more than others. But almost everyone can benefit from help and support from others, whether family and friends, religious groups, support groups or professional counselors. Reach out to whoever you feel comfortable with to discuss your concerns.
The best way to reduce the risk of lung cancer is not to smoke and to avoid breathing in other people’s smoke. If you stop smoking before a cancer forms, the damaged lung tissue gradually starts to repair itself. Since radon is an important cause of lung cancer, you can reduce your exposure to it by having your home tested and treated, if needed. Lastly, a healthy diet with lots of fruits and vegetables may also help reduce the risk of lung cancer. A rich diet helps protect both smokers and non-smokers against lung cancer. Although we know how to prevent most of the lung cancers, presently we don’t know how to prevent all of them. Always remember it is never too early or too late to stop smoking. Stay healthy and stay safe!