Lung cancer is the leading cause of cancer death worldwide and the third common cancer in South African men.
The biggest risk factor is smoking, and most lung cancer deaths are related to this. The longer and more you smoke, the higher your risk. It’s also advisable to stop smoking when you start treatment. Some other risk factors are work, environmental exposure and family history.
Lung cancer unfortunately can’t always be prevented. There are lung cancer subtypes associated with patients who have never smoked before or only have a light smoking history. These are usually cancers that have a specific mutation.
Diagnosis starts with a chest X-ray. You would usually see your GP with your presenting complaint. The most common symptom is a persistent cough. Often patients are treated for chest infections or newly diagnosed asthma or allergies for long periods of time before lung cancer is suspected. It’s important that if you have a cough that isn’t going away, that at least a chest X-ray is done. Other symptoms can be chest pain, coughing up blood, shortness of breath, hoarseness, and persistent or new onset wheezing.
It’s also unfortunate that lung cancer often doesn’t have any symptoms, until it’s advanced. Sixty percent of cases will present with metastases (spread to another part of the body). The more advanced the disease is at diagnosis, the worse the prognosis.
There is no good screening test for lung cancer that has been shown to be beneficial. Recently the low-dose CT scan has shown to help detect lung cancer earlier, but only in patients with a high-risk for developing lung cancer.
Symptoms of advanced disease can be fatigue, loss of weight, bone pain (often in the back or hips) and even paralysis if there is spread to the vertebrae and it collapses onto the spinal cord. If it has spread to the brain, patients can present with headaches, strokes or seizures. If it spread to the liver, patients can have jaundice. Sometimes lung cancers are associated with other syndromes, or paraneoplastic symptoms which means symptoms that don’t seem as if they are associated with the cancer.
After an initial diagnosis is made on X-ray, then further imaging is indicated, such as CT scan. We advocate for the least invasive biopsy as possible. This decision along with the treatment should be made in a multi-disciplinary team setting, which includes a medical and radiation oncologist, cardiothoracic surgeon, pathologist and interventional radiologist.
Core needle biopsy that is sonar or CT-guided is the least invasive way to get tissue. If this can’t be done, then the cardiothoracic surgeons can use techniques such as bronchoscopy, mediastinoscopy and thoracoscopy which aren’t as invasive as surgery. These are scopes which go into the chest or pleura, where a piece of tissue can be taken from.
It’s exceptionally rare to need open surgery to make a diagnosis. Surgery is usually reserved for early stage disease that is for the intention of removing cancer with the intention of cure.
A proper tissue biopsy is vital to do proper testing which guides oncologists on which treatments to use. Tests such as sputum or fluid or fine needle aspiration for cells are usually inadequate to make a correct diagnosis.
Once the diagnosis is made, other scans, such as a PET-CT and MRI for the brain, can be used to stage the cancer correctly. Staging is essential as it helps us to decide the correct treatment.
The two main categories of lung cancer are small cell (15%) and non-small cell lung cancer (85%). Small cell lung cancer is usually associated with smoking and behaves very aggressively and spreads rapidly. It usually responds well to chemotherapy and radiation but also tends to relapse very quickly. A combination of chemotherapy and immunotherapy can also be used to treat small cell lung cancer.
Non-small cell lung cancer is further divided into three different subtypes, mainly adenocarcinoma (40%), squamous carcinoma (30%) and large cell carcinoma. The treatment of the different subtypes differs, thus the importance to get tissue for the correct diagnosis. Treatment also differs according to stage.
Treatment can either be surgery alone, if an early stage. If you aren’t fit enough or eligible for surgery, then stereotactic radiation can be used. This can be equally effective as surgery.
Adjuvant chemotherapy is used to decrease the risk of recurrence in some Stage 2 cancers. We can also use neo-adjuvant treatments, meaning that the tumour and lymph nodes can be shrunk down to make them operable.
Some more locally advanced or Stage 3 cancers can be treated with a combination of chemotherapy and radiation, definitively or curatively. There is also now immunotherapy treatment available to give after definitive chemo-radiation to further prevent relapse or prolong patients’ lives.
Stage 4 cancers for non-small cell lung cancer are often treated with a combination of chemotherapy and radiation, or chemotherapy alone or chemotherapy with immunotherapy, or immunotherapy alone. Oncologists need to do a PD-L1 test on the tissue biopsy to decide if the cancer will respond well to immunotherapy or not. Immunotherapy has changed the prognosis of lung cancer patients significantly.
Adenocarcinomas are slightly different as they can be tested using a next generation sequencing test. This extracts DNA or RNA from the tissue to test it for a driver mutation which can respond to targeted therapies. Targeted therapies are usually oral medications. Driver mutations are quite infrequent. Less than 15% of patients will have a mutation and some mutations occur in as little as 1% of lung cancers. These targeted therapies are essential, and we test all patients with adenocarcinomas for them, as patientsoften respond exceptionally well to targeted therapies and for relatively long periods of time. These drugs also have significantly less toxicities than chemotherapy.
Radiation techniques have also improved greatly. Some patients can often be treated with targeted radiotherapy or stereotactic for a specific area, if the lesions are few and small enough to convert patients to curable.
Many of the newer therapies are difficult to access in terms of cost and availability but have greatly changed the outcomes of lung cancer patients.
Always ask your doctor about clinical trials, this will help you gain access to newer therapies. These are available in both public and private healthcare settings.
Dr Ronwyn van Eeden is a specialist physician and medical oncologist in private practice in Rosebank. She is also an honorary consultant at Chris Hani Baragwanath Academic Hospital and a member of the executive committee for SASMO and editor of the Journal of Clinical Oncology SA edition. She has a special interest in breast and lung cancer with numerous publications on the subject.
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