What happens in lung cancer, exactly?

What is it?

Cancer is the uncontrolled growth of your own cells, and in lung cancer this growth causes tumors to form in your lungs. It can spread to other parts of the body. Typical symptoms include coughing, loosing weight, being short of breath, and chest pain.

Every year there are around 1.8 million new cases of lung cancer worldwide, and 1.6 million deaths. In the US, around 17% survive for at least five years after the diagnosis. Lung cancer is the most common cancer affecting men, and in the US, men have an 8% chance and women a 6% chance of developing it during their lifetime.

What causes it?

Smoking is the main contributor to lung cancer. It account to about 85% of lung cancer cases. Passive smoking, ie. inhaling the smoke from someone else, also increases the risk for people who live near smokers. Radon, asbestos and air pollution have been found to have an effect. About 8% of lung cancer is thought to be caused by genetics.

What happens during it?

The growth, death, and birth of our cells is carefully regulated through the genes in each cell and also the messages that cells send to each other. Cancer is the result of an unfortunate mutation in a gene that either promotes cell growth and reproduction or suppresses it. Cells communicate by chemicals that attach to specific receptors on other cell’s surfaces, and while in a normal situation the growth of cells is strictly regulated, a tumor can form, for example, if a receptor-producing gene mutates so that the cell is no longer responsive to inhibiting signals.

Tobacco smoke contains lots of carcinogens: that is, substances that have the potential to harm the DNA inside our cells and cause mutations to our genes. The more exposure we get, the more likely a mutation in a location that leads to cancer formation is. People with lung cancer tend to cough because the tumors press the cough receptors in the lungs, whose job it is to make the person cough away anything unfamiliar. Cancer leads to the breaking down of proteins and fats, and also reduces the building of new proteins – hence the characteristic weight loss. Breathing difficulties and chest pain in lung cancer are mostly caused by the physical space the tumor takes.

How can it be treated?

Cancer can be treated effectively with surgery if it’s spotted so early that it hasn’t had the time to spread to other parts of the body. Lung cancer, however, metastasizes relatively quickly, and patients often only start showing symptoms after it has done so.

Other, less specific treatments can also be used. Their aim is most often target quickly dividing cells, which include cancer cells but also hair cells, for example. The DNA is most vulnerable during the process of cell division, and many form of chemotherapy and radiotherapy take use of this fact. Both of these treatments can be very uncomfortable to the patient, and a challenge in cancer treatment is trying to find a balance between killing enough cancer cells while not harming too many healthy ones.

As with all cancers, the prognosis is relatively good if the disease is noticed relatively early, but falls sharply as the disease progresses. It is therefore a good idea to seek a medical opinion as soon as any symptoms start to appear. Raising awareness of the dangers of smoking is also very important – while others might not be entitled to stop someone else from smoking, they should be fully informed about the risks they are putting themselves into.


Sources: https://en.wikipedia.org/wiki/Lung_cancer#Management, http://www.pathophys.org/lung-cancer/, http://www.nhs.uk/Conditions/Cancer-of-the-lung/Pages/Treatment.aspx, https://en.wikipedia.org/wiki/Cancer#Systemic_symptoms, http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/chemotherapy/how-chemotherapy-drugs-work,



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