10 Chapter 11
Describe the effects of smoking on the mammalian gas exchange system, with reference to the symptoms of lung cancer;

Lung Cancer

Carcinogens are chemicals that can cause cells to become cancerous. Cigarette smoke contains many of these carcinogens. They can cause mutations in the DNA of lung cells, which could lead to uncontrollable cell growth and eventually the formation of a malignant tumour.

Malignant -meaning cancerous- tumours grow rapidly and uncontrollably which means that they can cause blockages to the air flow in the lungs. This can cause the body to struggle with the intake of Oxygen as the rapid growth of the malignant tumours causes a decrease in gas exchange and surface area within the lungs and will give the person shortness of breath.

Lung cancer causes 35,000 deaths per year in the UK. People who smoke are 20 times more likely to get lung cancer then people who don't smoke. However, lung cancer can spread all over the body. Cancerous cells may break away from the original tumour and form tumours-lumps of disorganised cells- in other parts of the body . This can make survival rates low. Some of the carcinogenic substances enter the blood stream in the lungs and are carried all over the body. Henceforth smoking increases the chance of getting cancer anywhere within the body.

Symptoms of Lung cancer:

  • A cough that doesn’t go away after two or three weeks
  • A long-standing cough that gets worse
  • Persistent chest infections
  • Coughing up blood
  • An ache or pain when breathing or coughing
  • Persistent breathlessness
  • Persistent tiredness or lack of energy
  • Loss of appetite or unexplained weight loss
  • Treatment for Lung Cancer

    First you need to be checked to see if you have small cell lung cancer or non small cell lung cancer:

    Small cell lung cancer is mostly treated with chemotherapy. Surgery is only suitable if there is no sign that the cancer has spread to the lymph glands in the centre of the chest (the mediastinal lymph glands). This is rare with small cell lung cancer. It has usually spread at the time of diagnosis. So chemotherapy is usually the main treatment. You may also have radiotherapy to treat this type of lung cancer.

    Non small cell lung cancer can be treated with surgery, chemotherapy, radiotherapy or a combination of these, depending on the stage when the cancer is diagnosed. Some people with advanced lung cancer may have biological therapy.