While cancer is known to be a deadly disease, it is lung cancer that accounts for the maximum number of deaths caused by cancer globally. This can be credited to mainly two factors. First, the disease affects an organ so vital for human survival. And second, lung cancer is usually diagnosed in advanced stages. Various stages of lung cancer
This article explains the different stages of lung cancer. Further, we discuss at what stage is lung cancer usually diagnosed and why it is so.
Understand The Staging Of Lung Cancer
Staging is the process of classifying a case of cancer-based on its severity and the extent of its spread. This helps provide the patient with the appropriate prognosis, treatment, and care.
Lung cancer is mainly of two types, small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Both types are distinct in their aggressiveness and how fast they spread. Hence, their staging is also based on different parameters. Before we delve into the specifics about what stage is lung cancer usually diagnosed, lets understand the stages better.
Non-small cell lung cancer (NSCLC)
NSCLC accounts for approximately 80 to 85% of lung cancer cases. This type usually originates from the lung and gradually spreads to the surrounding lymph nodes and organs.
The staging of NSCLC is done on the following basis:
- The size and location of the tumor
- The number of lymph nodes cancer has spread to
- Whether it is metastasized or not
Based on the above parameters, non-small cell lung cancer is broadly divided into four stages. The stages are explained below:
- Stage 1: Here, the cancer is in its earliest stage. The tumor affects only one of the lungs and has not yet spread to the nearby lymph nodes or tissues. If diagnosed at this stage, lung cancer can be treated relatively easily. Oncologists usually recommend surgical removal of the tumor to prevent its spread.
- Stage 2: At this stage, the tumor is usually larger than 3 cm. It might have spread to the nearby lymph nodes but not nearby organs. Oncologists usually suggest surgical removal of the tumor, if possible, along with chemotherapy or radiotherapy.
- Stage 3: The lung cancer tumor at stage 3 is generally bigger than 7 cm in size and has spread to the center of the chest. At this stage, cancer may or may not affect the lymph nodes at the opposite lung or near the collarbone. Treatment and full recovery at this stage are usually challenging.
- Stage 4: This is the most advanced form of cancer. Here, the tumor has metastasized to the nearby lymph nodes and organs. At this stage, the doctors main concern is making the patients survival comfortable and pain-free rather than recovering.
In cases of non-small cell lung cancer, researchers have estimated the 5-year survival rates based on the stage in which the cancer is diagnosed. For a localized form of lung cancer, the 5-year survival rate is 63%, while the same for regional and advanced forms is 35% and 7%, respectively. The overall 5-year survival rate of NSCLC is 25%.
Small Cell Lung Cancer (SCLC)
SCLC is found in only 15% of the cases of lung cancer. It is, however, very aggressive and spreads much faster than NSCLC. In 70% of the cases, small-cell lung cancer is diagnosed only when it has metastasized to the surrounding lymph nodes or even organs.
The staging of SCLC is done on the basis of the extent of its spread. It broadly has two stages:
- Limited Stage: At this stage, cancer affects only one side of the chest. It could spread from a point on one lung to the nearby lymph nodes on the same side.
- Extensive Stage: At this stage, cancer spreads to the other part of the chest too. It affects both the lungs, the surrounding lymph nodes, and possibly other organs too.
As SCLC is more aggressive than NSCLC, its 5-year survival rate is only 7%. However, if it is diagnosed when still localized, the survival rate is 27%. This declines to 16% and 3% in the regional and advanced stages, respectively.
At What Stage Is Lung Cancer Usually Diagnosed?
In most cases, lung cancer is not diagnosed until it has spread regionally or is in the advanced stage. This is mostly the case with stages 3 and 4.
Lung cancer can be difficult to spot during routine tests if not paid close attention to it. And, in most cases, people opt for the proper screening and diagnosis only when the symptoms of this disease are obvious.
Why Is Early Diagnosis Of Lung Cancer So Rare?
Out of all the annual cases of lung cancer, most of the diagnoses are in stage 3 or 4. Early diagnosis of this disease is not encountered very often. But why is it so?
The symptoms of lung cancer in its early stages can be easily mistaken for other lung infections or illnesses. These symptoms include persistent cough, shortness of breath, chest pain, wheezing, loss of appetite, sudden weight loss, and frequent respiratory infections. On the appearance of these symptoms, people usually take common cold medications or treatments for lung infections and move on.
Screenings for lung cancer also have some side effects. This is why it is mostly suggested for people who are more prone to developing lung cancer. It includes people who are regular smokers or have quit smoking in the past 15 years and are frequently exposed to occupational and environmental carcinogens.
However, the information and awareness regarding these screening guidelines are not as widespread. Hence, many people skip regular cancer screenings despite being at a high risk of developing that disease.
Lung cancer is a disease that shouldn be taken lightly. Hence, spreading awareness about the symptoms, screenings, diagnosis, and treatment of this disease is of immense importance. If you notice any such pulmonary symptoms, don ignore them. Instead, consult with an expert doctor about your symptoms. Also, if you fall under the category of people at a higher risk of developing lung cancer, make sure you undergo regular screening tests as per the guidelines.
For expert consultation and care for lung cancer, you can visit Dr. Arvind Kumar at Medanta Hospital, Gurgaon. With an all-encompassing team of cancer care professionals, Dr. Arvind provides the only comprehensive A to Z lung cancer treatment plan in India.
1. Can stage 1 lung cancer be detected?
Detection of lung cancer at stage 1 is very rare as the case is almost always asymptomatic. This is because the current standard cancer screening method, a low-dose CT scan (LDCT scan), is not as widely available. Also, due to the associated risks, it is not usually recommended by doctors when there are no indicative symptoms.
2. What is the first hint of lung cancer?
The first and most important indicator of lung cancer is a persistent cough. If your coughing doesn subside after 2 weeks of taking medications, consult with your doctor. Continuously coughing up dark phlegm or hints of blood is a warning sign in this case.
3. How is the lung cancer stage determined?
The stage of lung cancer is mainly determined based on how much the cancer has spread. In its early stages, the cancer is localized, affecting only a part of the lungs and possibly the surrounding lymph nodes. As it advances on stage, it spreads to other parts of the chest and other organs.