Lung cancer is not a single disease but rather a group of cancers that develop in the lung. Cancer occurs when cells mutate (change abnormally) and begin growing out of control. These cells form tumours that can often be seen on a chest X-ray.
Some tumours that form in the lung are benign (noncancerous), meaning they do not grow into surrounding areas or spread in the body. Malignant (cancerous) tumours grow into nearby tissues or spread to other parts of the body (metastasize).
A biopsy is required to determine the diagnosis of a tumour that appears suspicious on imaging.
Many patients wonder why they developed lung cancer or if they are at a high risk for the disease.
In general, cancer develops after the genetic material in cells changes abnormally and the cells begin growing out of control. When there are enough of these abnormal cells, they can form a tumour.
Lung cancer often is a result of chronic exposure to tobacco smoke, either from smoking or from being around second-hand smoke. It also is linked to exposure to certain substances like radon gas or asbestos, or from prior radiation treatment to or over the lungs.
People who have had lung cancer before are at higher risk of recurrence. People who have a close relative who has had lung cancer are slightly higher risk of developing the disease.
Lung cancer has 2 main types. Each type is categorized by how the cancer cells look under a microscope:
• Non-small cell lung cancer
- Squamous cell carcinoma
- Bronchoalveolar carcinoma
- Large-cell undifferentiated carcinoma
• Small cell lung cancer
Other factors in diagnosis and treatment planning
There are additional considerations beyond type and subtype that affect recommendations your care team may make for treatment.
• Tumour size offers clues about how quickly the tumour may have developed and how likely it is to spread beyond the lung. Larger cancers are more likely to progress to the lymph nodes.
• Grade assigns a numeric value to describe how abnormal the cancer cells appear under the microscope. The higher the number the more aggressive the cancer is. Lower numbers are usually is associated with a slower growth
Determination of stage of lung cancer at diagnosis is important to plan best treatment modality. Stage of the Cancer is described based on:
• Size of the tumor
• Location of the cancer
• Whether the cancer has spread and, if so, to where
This information is also helpful in determining prognosis (probable outcome based on the experience of others).
The stages of lung cancer are:
Stage 1: Cancer is found in the lung, but not progressed to the lymph nodes or distant organs. Surgery is the best modality at this stage. However, decision is based on other factors also like fitness of the patient to undergo surgery.
Stage 2: Cancer has progressed from the lungs to nearby lymph nodes. Surgery followed by drug therapy is recommended.
Stage 3: Cancer is in the lung and has progressed to distant lymph nodes. Chemotherapy or chemoradiation may be recommended before and after surgery. Targeted therapies may be recommended after surgery.
Stage 4 (Metastatic): Cancer has progressed beyond the lung to distant lymph nodes and other organs. This advanced stage of cancer is commonly managed by drug therapy alone.
Recurrent: Cancer that has come back after treatment. This may be managed by some combination of surgery, drug therapy, and radiation therapy.
Many early stage lung cancers can be detected by screening or incidentally as part of xrays done for other reasons. Lung cancers are often found after they produce discomfort. Signs and symptoms of lung cancer include:.
• A chronic cough
• Coughing up blood
• Shortness of breath
• Respiratory infections that won’t go away
• Chronically hoarse voice
• Sudden, unexplained weight loss
Lung cancer risk factors include:
• Smoking: Your risk of developing lung cancer increases with the number of cigarettes you smoke each day and the number of years you have smoked. Quitting at any age lowers your risk of developing lung cancer.
• Exposure to radon gas: radon results from the breakdown of uranium in certain soils. The gas may make its way into homes, especially in basements.
• Exposure to asbestos: people exposed to asbestos through their work are at greater risk of developing a condition called mesothelioma. Mesothelioma is a type of cancer that starts in the lining around the lungs.
• Exposure to radiation: Radiation therapy to the chest from childhood through early adulthood increases lung cancer risk.
• Family history: people with a close relative who had lung cancer are at slightly higher risk for developing lung cancer themselves.
• Prior lung cancer: people who have had lung cancer before are at greater risk for recurrence of lung cancer.
If the diagnosis of Lung Cancer has already been made outside, we will have your results sent to our pathologists (doctors specializing in cancer diagnosis). They will review your test results and confirm or correct your diagnosis.
At our centre, the diagnostic phase is tailored to each individual patient. If further testing is required our team will work with you to determine which tests you need. Tests may include:
Blood Tests (Blood Draws)
Several blood tests are required to help establish the diagnosis and plan the further course of treatment. Our team will carefully look at all the test that might have been done and recommend additional tests if required.
Thoracic Imaging (Radiology)
To obtain the most precise understanding of your cancer, your doctor may schedule you for different types of imaging that diagnose cancer. If you have been screened elsewhere and received abnormal results, we may perform additional imaging, if needed.
Lung Biopsy (Pathology)
If your imaging or other screening tests show that you may have cancer, you will need a biopsy. This test takes a tiny sample of cells from abnormal areas of tissue. This is done under guidenace of an imaging modality depending on the location of the tumour.
• Ultrasound guided Lung Mass Biopsy
• CT (Computed Tomography) Guided
• EBUS Biopsy (Lymph Nodes or Centrally located tumours)
The clinical stage or the initial staging before initiation f treatment is vitally important for patients with Lung Cancer as it is not only the basis for deciding on a patient's treatment plan, but is also the basis for comparison when checking into the patient's response to treatment. This will require
• Whole Body PET/CT Scan
Positron emission tomography (PET) Scan is a special imaging modality wherein a small amounts of radioactive materials called radiotracers or radiopharmaceuticals are injected in to the veins. These radiotracers accumulate in areas where there may be tumour cells and will be detected using a special camera and a computer. By identifying changes at the cellular level, PET scan may detect the early onset of disease before other imaging tests can and also help in identifying whether the disease is limited to lungs or has spread beyond it.
• MRI Brain
Certain patients will require MRI of the brain to rule out spread to brain which sometimes is not picked up by PET scan .
• Endo-Bronchial Ultrasound Guided staging of Mediastinal Lymph nodes
This test is used to check for spread of the cancer to regional or Mediastinal Nodes. It involves the use of a special bronchoscope which has an ultrasound probe at its tip. This is used to visualise the lymph nodes from which needle biopsy is taken and which is then subjected to evaluation by Pathologists for presence of cancer cells
This is a surgical procedure which is advised in patients with Lung Cancer to conclusively rule out involvement of Mediastinal Nodes in the central part of the chets, which is the space between the heart, lungs, windpipe, and esophagus.
Small Cell Lung Cancer
In general, small cell lung cancer patients present at a stage where the cancer has already spread beyond the lungs. Such patients are usually treated with chemotherapy. Surgery is limited to very early stage disease in patients who have not yet have lymph nodal or distant spread. 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 (NSCLC)
This cancer is treated by Surgery, Chemotherapy and Radiotherapy or in combination. If detected early Surgery appears to offer the best long-term results.
For stage I NSCLC, surgery may be the only treatment needed. This may Involve removal of piece of lung as described below
The Right and the Left Lung is made up of parts which are called lobes.
Right Lung – Upper, Middle & Lower Lobe
Left Lung – Upper & Lower Lobe
Surgical removal of a lobe is known as lobectomy. Based on the current evidence wherever feasible removal of the lung cancer containing lobe is considered as the standard treatment option. Along with the lobe lymph nodes around the lung and in the mediastinum will be taken out also. Everything is sent for a detailed evaluation by a pathologist who will give the final or the pathological staging of the tumour. This will help take decision regarding requirement of any additional treatment.
• Segmentectomy or Wedge Resection
Done rarely and is generally reserved only for very small stage I cancers and for patients with other health problems that make removing the entire lobe dangerous. Still, most surgeons believe it is better to do a lobectomy if the patient can tolerate it, as it offers the best chance for cure.
Pneumonectomy means removal of the entire lung of one side either the right or the left. Its is done only in cases where complete removal of the lung cancer is not possible with a lobectomy. Experienced surgical teams will avoid doing a pneumonectomy using there expertise wherein they can salvage the lobes by doing special surgeries like sleeve resection. However despite everything sometimes pneumonectomy is unavoidable.
After surgery, the removed tissue is checked to see if there are cancer cells at the edges of the surgery specimen (called positive margins). This could mean that some cancer has been left behind, so a second surgery might be done to try to ensure that all the cancer has been removed. (This might be followed by chemotherapy as well.) Another option might be to use radiation therapy after surgery. For people with stage I NSCLC that has a higher risk of coming back (based on size, location, or other factors), adjuvant chemotherapy after surgery may lower the risk that cancer will return. New lab tests that look at the patterns of certain genes in the cancer cells may help with this.
Non-Surgical Option for Stage I NSCLC
For patients with serious health problems that prevents them from having surgery, stereotactic body radiation therapy (SBRT) or another type of radiation therapy may be considered as an alternative main treatment. Radiofrequency ablation (RFA) may be another option if the tumour is small and in the outer part of the lung.
Stage II NSCLC
People with stage II NSCLC who are otherwise fit for surgery are treated by removal of the lung cancer by lobectomy or sleeve resection. Sometimes removing the whole lung (pneumonectomy) is needed. Any lymph nodes likely to have cancer in them are also removed. The extent of lymph node involvement and whether or not cancer cells are found at the edges of the removed tissues are important factors when planning the next step of treatment.
After surgery, the removed tissue is checked to see if there are cancer cells at the edges of the surgery specimen. This might mean that some cancer has been left behind, so a second surgery might be done to try to remove any remaining cancer. This may be followed by chemotherapy (chemo). Another option is to treat with radiation, sometimes with chemo.
Even if positive margins are not found, chemo is usually recommended after surgery to try to destroy any cancer cells that might have been left behind.
In case of serious medical problems that would keep you from having surgery, you may get only radiation therapy as your main treatment.
Treating stage III NSCLC
Stage IIIA NSCLC
Treatment may include some combination of radiation therapy, chemotherapy (chemo), and/or surgery. For this reason, planning treatment for stage IIIA NSCLC often requires input from a multidisciplinary team consisting of a medical oncologist, radiation oncologist, and a thoracic surgeon. Treatment options depend on the size of the tumor, its location, which lymph nodes it has spread to and the overall health and fitness for tolerating treatment.
These patients usually require chemotherapy to start the treatment which may or may not be combined with radiation therapy (also called chemoradiation). Chemotherapy in this setting that is before surgery is called Neo-Adjuvant Therapy (NACT or NACTRT). After a few cycles of NACT/RT the patient os revaluated and in patients with good response and absence of disease progression surgery is consoderd if the surgeon thinks the entire disease can be removed and the patient os fit to undergo such treatment. In some cases surgery may be offered as the first followed by chemo, and possibly radiation therapy if it hasn’t been given before.
Stage IIIB NSCLC
Patients with Stage IIIB NSCLC have lung Cancer that has spread to lymph nodes that are near the opposite lung or in the neck or the have tumour that has grown into / invaded nearby important structures in the chest. These cancers can’t be removed completely by surgery. As with other stages of lung cancer, treatment depends on the patient’s overall health. Most of such patients are not good surgical candidates and maybe offered definitive treatment by combination of chemo and radiotherapy. Some people can even be cured with this treatment. If the cancer stays under control after 2 or more treatments of chemoradiation, immunotherapy can be considered for keeping the disease stable.
In patients not fit to undergo combination of chemotherapy, either of the modality alone may be used and these patients can be considered for immunotherapy. These are difficult to treat cancers and have relatively worse prognosis.
Stage IV NSCLC
Spread of the Lung cancer beyond the confines of the chest corresponds to Stage IV NSCLC. At this stage Lung Cancer cannot be cured, however it can be controlled using chemotherapy (chemo), targeted therapy, immunotherapy, and radiation therapy. This may increase the life of the patients and may improve the quality of life by relieving symptoms but these are not likely to cure.
The best prevention is to avoid exposure to tobacco smoke and to avoid exposure to certain workplace chemicals. A heathy diet rich in fresh fruits and vegetables and regular exercise are recommended for your overall health.
Treatment of Lung Cancer
The treatment of Lung cancer is guided by:
• The Type of Lung Cancer
• The Stage of Lung Cancer
• Patient overall condition and Fitness level