Every year over 10,000 people in Australia develop lung cancer. In some parts of the world, the rates of lung cancer are much higher.
Lung cancer occurs when abnormal cells in the lung multiply faster than normal, causing a lump, or tumour. These cancerous cells can grow into the surrounding lung and also travel to sites outside the lung, including lymph nodes nearby or other sites further from the lungs such as bones, liver and brain. These ‘secondary’ deposits are called metastases.
In addition, there are many cancers that start somewhere else in the body e.g. breast or bowel, and then spread to the lungs.
These are called metastases to the lung but are not lung cancers, although they may cause symptoms from being in the lungs. Lung cancer can be rapidly growing, and may grow quite large before it is detected. It may also have spread outside the lungs to another site before it is detected.
If lung cancer spreads outside the lungs it is treatable, however ‘cure’ is unlikely, and treatment is then aimed at slowing the growth of the tumour and reducing symptoms. Unfortunately, lung cancers overall do not have a good prognosis and there is a lot of work trying to improve results in this disease.
There are two main types of lung cancer: Non-Small Cell Lung Cancer and Small Cell Lung Cancer. These can behave differently and respond differently to treatment. This means that the approach to treating them is also different.
What Are the Causes of Lung Cancer?
Cigarette smoking is known to increase the incidence significantly and is the biggest risk factor for developing lung cancer. Anything toxic inhaled into the lungs, such as cigarette smoke, asbestos, radon and hydrocarbons have all been associated with lung cancer.
Lung cancer can also occur in non-smokers, although the risk is much smaller than for smokers. Lung cancer is rare before the age of 40, with the risk increasing with age. Asbestos exposure and cigarette smoking together multiply the risk of developing lung cancer.
What Are the Symptoms of Lung Cancer?
Common lung cancer symptoms are:
- a cough,
- shortness of breath and
- coughing up blood.
Patients with lung cancer may also
- feel generally unwell, fatigued or
- have poor appetite and
- may lose weight.
Other symptoms can be caused by secondary deposits outside the lung, such as symptoms from deposits in the brain (headaches, nausea, dizziness, fitting, loss of limb function), bone pain and abdominal pain.
What Are the Treatments for Lung Cancer?
The recommended treatment for lung cancer depends on which type of cancer a patient has and the stage (extent) of the cancer at the time of diagnosis, as well as the general health of the individual. If the cancer has been diagnosed early then surgery may be all that is required.
However often surgery is followed by chemotherapy or radiation therapy. Chemotherapy and radiation therapy can be used together if surgery is not possible.
New advances allow delivery of highly targeted radiation therapy called stereotactic ablative radiation therapy (SABR), also known as stereotactic body radiation therapy (SBRT), allowing small, inoperable lung cancers to be treated with curative radiation therapy.
These new techniques offer high focal doses of radiation in either one or a few treatments which are more likely to control a lung cancer with less risk of damaging normal tissues such as the surrounding lung. This field of treatment is rapidly expanding and capitalises on advanced planning techniques, superior body immobilisation and highly technical image guidance technology.
Chemotherapy and radiation therapy may also be used to reduce the symptoms from lung cancer that is not curable, depending on the site of tumour and the symptoms to be managed. For instance, coughing up blood and pain can be effectively treated with local palliative radiation therapy to the cancer.
Some forms of lung cancer (mostly occurring in young, non-smoking women) may be treated with special drug therapy that act against cancer cells, even if the cancer has spread (anti-epidermal growth factor receptor agents).
How Effective is Radiation Therapy for Lung Cancer?
The effectiveness of radiation therapy for lung cancer depends on the specific type of cancer and again, how big it is and how much it has spread. Small cell lung cancer is very sensitive to radiation therapy (as well as chemotherapy). Non-small cell lung cancer is also treatable with radiation therapy, and chemotherapy given at the same can increase the effectiveness.
This combination treatment is often recommended in cases where surgery is not feasible but the cancer is still limited to the lung plus or minus local lymph nodes.
SABR uses high doses of very targeted radiation therapy, over one or a few days (rather than a four to six weeks) and is an exciting new approach to treating small lung cancers in patients that are not suitable for an operation. The effectiveness appears to have similar results to surgery in terms of local control, without being invasive or carrying the potential risks associated with surgery.
SABR can be an appealing option particularly as more patients with other concurrent illnesses are being diagnosed. There are several ongoing scientific studies (clinical trials) further evaluating this new and sophisticated technique.
Radiation therapy is useful in many lung cancer patients to reduce distressing symptoms (palliation), and chemotherapy can be helpful in shrinking some cancers that have spread to other parts of the body.
What Are the Side Effects of Radiation Therapy?
Side effects during/soon after treatment (Early or ‘acute’ side effects)
General – Fatigue is a common side effect of radiation therapy and is more likely to occur in the second half of treatment and is variable between patients. This may persist for a few weeks after treatment and usually settles within 4-6 weeks once radiation therapy is completed.
Local – All other side effects of radiation therapy come from the structures/organs in and just next to where the radiation is being targeted.
Swallowing issues – heartburn like symptoms can occur with radiation therapy. Some patients may temporarily need to have a soft diet during this time and avoid hot drinks and spicy food. Medications can be used over the counter or prescribed by your doctor to aid in symptom control.
Skin changes – redness or tanning of the skin can occur in the area of your chest and back which is receiving treatment. Some patients may notice some itching associated. This temporary problem usually settles down 2-4 weeks after treatment and can be relieved by creams on advice from the treating team. Hair loss can also occur in the area that is being treated.
Side effects well after treatment (Late or long-term side effects)
Late side effects may occur a few months or years after treatment though they are much more rare than early side effects. Depending on the problem these may occur once and then go or may be more persistent over the long term or may come and go over time.
Breathing difficulty – 1 to 6 months after radiation therapy some patients can develop respiratory complications due to inflammation such as shortness of breath, cough and fever. It is possible to alleviate these symptoms with medication that can be prescribed by your treating team.
Lung scarring – a small minority of patients can develop potentially permanent scarring of the healthy lung tissue that occurs 6 months after radiation therapy. Usually the amount of scarring is not significant but may result in shortness of breath.
Arm weakness or numbness – this rare problem can sometimes occur in the treatment of tumours that are positioned in the upper part of the lung. The nerves that control arm and hand function lie just behind the collarbone and if damaged can cause numbness or weakness but is expected in only 1 in 1000 patients.
Spinal cord damage – this rare problem can sometimes occur in the treatment of tumours that are positioned near the spine. Damage to the spinal cord can result in numbness and weakness below the level of injury but is expected in only 1 in 1000 patients.
Developing another cancer – radiation can cause another cancer in the future but does not occur until at least 10 years after radiation therapy.
The best person to discuss radiation therapy for lung cancer with is a Radiation Oncologist. You can ask your respiratory physician (lung specialist) or general practitioner (GP) for a referral to a Radiation Oncologist for a discussion about how radiation therapy might fit into your treatment program.
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