The lungs are paired cone-shaped organs situated in the thoracic cavity. They are covered with the double-layered pleural membranes (membrane directly covering the lung is called visceral pleura and the external one is called parietal pleura) that secrete and enclose a lubricating fluid within the space between them (the pleural cavity). The right lung has 3 lobes and is slightly bigger than the left lung, that has 2 lobes.
When air is inhaled, it travels from the nostrils into the lungs via trachea (windpipe) and its two branches called bronchi. Inside the lungs, bronchi further divide into small lobular bronchi and keep on dividing inside the lobes to form a network of microscopic branches called bronchioles. At the end of each bronchiole are small grape-like air-sacs called alveoli that act as a site of gases exchange during respiration. The main function of the lungs is to bring about this gases exchange, that is, intake of oxygen and removal of carbon dioxide.
Epidemiology of Lung Cancer in Delhi
Lung cancer is one of the leading causes of cancer across the world. But in Delhi, it is on the rise. With the increasing air pollution, incidence of lung cancer is rising even for non-smokers in Delhi. 30 years back, smokers accounted for almost 90% of cases of lung cancer.
But in the current scenario, it is almost equally divided between smokers and non-smokers. And in the younger age group, less than 50 years, around 70% of lung cancer cases are non-smokers. The average age of lung cancer is also falling in Delhi. 20 years back, it was 50-60 years, but currently it has come down to 30-40 years. Also, the incidence is on the rise in females, with 40% of cases being women.
Types of Lung Cancer
Broadly, lung cancer is mainly divided into 2 types:
- Non-small cell lung cancer (NSCLC) that constitutes about 80% to 85% of all lung cancers and
- Small cell lung cancer (SCLC).
Histologically, lung cancer can be of several types such as squamous cell carcinoma, adenocarcinoma, large cell carcinoma, neuroendocrine tumors, large cell neuroendocrine carcinoma, small cell carcinoma, and lung carcinoid tumors among others. Adenocarcinoma, squamous cell carcinoma, and large cell carcinoma are grouped together as NSCLC. SCLC, also known as oat-cell carcinoma is a type of neuroendocrine tumors, which tend to grow and spread very rapidly.
What is the Staging of Lung Cancer?
Staging of Non-Small Cell Lung Cancer (NSCLC)
Tis – Pre-cancerous changes or carcinoma in situ.
T1 – Cancer is </= 3 cm in greatest dimension, without invasion of pleural membrane or mainstem bronchus. It may be further sub-divided as below.
T1mi– Cancer is minimally invasive adenocarcinoma </=3 cm in greatest dimension and invasion </=5 mm.
T1a – A tumor </=1 cm in the greatest dimension.
T1b – A tumor >1 cm but </=2 cm in the greatest dimension.
T1c – A tumor >2 cm but </=3 cm in the greatest dimension.
T2 – Tumor is >3 cm but </= 5 cm in greatest dimension. It has invaded into the main bronchus but has not affected the carina or invades the visceral pleura, or is partially choking the airway
T2a – A tumor >3 cm but </=4 cm in the greatest dimension
T2b – A tumor >4 cm but </=5 cm in the greatest dimension
T3 – A tumor >5 cm but </=7 cm in the greatest dimension that has invaded into the parietal pleura, chest wall, phrenic nerve, or the membranes surrounding the heart (parietal pericardium); or
There are 2 separate primary tumor nodules within the same lobe.
T4 – A tumor >7 cm in the greatest dimension that has invaded into the diaphragm, mediastinum, heart, large blood vessels, trachea, recurrent laryngeal nerve, esophagus, backbone, or carina; or
there is another tumor nodule in the adjacent lobe of the same lung.
N0 – No spread of cancer to nearby lymph nodes
N1 – Cancer has spread to intraparenchymal, peribrochial or ipsilateral hilar lymph nodes.
N2 – Cancer has spread to subcarinal or ipsilateral mediastinal lymph nodes
N3 – Cancer has spread to contralateral mediastinal lymph nodes or supraclavicular nodes
M0 – Cancer has not spread to distant body parts
M1a – Cancer has spread to cause pleural nodules or pleural effusion, OR pericardial nodules or pericardial effusion.
M1b – Single tumor deposit in a single distant organ or to a non-regional lymph node.
M1c – Multiple tumor deposits in single or multiple distant organs.
|0||Tis N0 M0|
|IA1||T1mi N0 M0|
|T1a N0 M0|
|IA2||T1b N0 M0|
|IA3||T1c N0 M0|
|IB||T2a N0 M0|
|IIA||T2b N0 M0|
|IIB||T1a-2b N1 M0|
|T3 N0 M0|
|IIIA||T1a-2b N2 M0|
|T3 N1 M0|
|T4 N0-1 M0|
|IIIB||T1a-2b N3 M0|
|T3-4 N2 M0|
|IIIC||T3-4 N3 M0|
|IVA||Any T Any N M1a|
|Any T Any N M1b|
|IVB||Any T Any N M1c|
Staging of Small Cell Lung Cancer (SCLC)
TNM staging discussed above also holds true for SCLC. But for practical treatment planning purposes, it may be broadly divided into LIMITED and EXTENSIVE disease.
Cancer is only on one side of the chest and might have spread to lymph nodes (including lymph nodes above the collarbone) on the same side.
Cancer has extensively spread throughout the lung, to other lung, lymph nodes on the other side of the chest, pleural membrane, distant lymph nodes, or distant organ.
Now, after discussing the staging, let’s discuss about the treatment of lung cancer.
What is the Treatment of Lung Cancer?
The treatment of lung cancer mainly depends on the histological subtype (small cell or non-small cell, and in NSCLC whether it is adenocarcinoma, squamous cell carcinoma, etc), presence of molecular abnormalities, lung function, performance status, etc.
Non-Small Cell Lung Cancer
Stage 0 (Tis N0 M0)
Surgery alone is the standard treatment for Stage 0 NSCLC. Other possible treatment option are brachytherapy, photodynamic therapy, etc.
Surgery is the mainstay of treatment for Stage I lung cancer. But assessment for operability is required by lung function tests and clinical assessment. In case of poor lung reserve or poor performance status, SBRT (Radiation Therapy) may be employed for treatment. Adjuvant chemotherapy may be added in some high-risk selected cases.
Surgery is uasually the preferred modality of treatment. But, as discussed above, in case of inoperability, chemotherapy with/without radiation therapy may be considered. Adjuvant chemotherapy is recommended in Stage II disease.
The treatment decision in Stage III NSCLC depends on many factors such as T stage, N stage, site and size of tumor, location and number of mediastinal nodes, operability of the patient, etc. After assessment of all such factors, a multimodality treatment with surgery, chemotherapy, and/or radiation therapy is planned.
Stage IV (Metastatic disease)
Most cases of metastatic disease are treated with a palliative intent. Treatment depends on the histological subtype (adenocarcinoma, squamous cell carcinoma, etc), presence of molecular abnormalities, site of metastasis, performance status, etc.
Chemotherapy, targeted therapy, and/or immunotherapy are the systemic treatment option in such cases. Also, other options like surgery, radiation therapy, etc may be considered in selected cases.
Small Cell Lung Cancer
Limited stage SCLC is preferably treated with chemotherapy and/or radiation therapy. Surgery may also be employed in selected cases.
Chemotherapy or Immunotherapy is the mainstay of treatment for extensive stage disease, and radiation therapy may be employed in selected cases.
Best Lung Cancer Specialist in Delhi
Dr Sunny Garg is a renowned Medical Oncologist in New Delhi with an experience of around 10 years of treating lung cancer patients. He has treated lung cancer patients with Chemotherapy, Targeted Therapy, Immunotherapy and Personalized Cancer Treatment. He is currently practicing at Manipal Hospital, Dwarka.
Diagnostic modalities available at our hospital include CT Guided Biopsy from Lung, Bronchoscopic Biopsy from Mediastinal Lymph Node, Bronchoscopic Biopsy from Lung, Thoracoscopic Lung Biopsy, etc. Other treatment facilities for Lung Cancer available are Lobectomy, Pnemonectomy, Stereotactic Radiosurgery, Lung Resection, Thoracotomy, Mediastinotomy, Visually Assisted Thoracoscopic Surgery, etc.
Call +91 9686813020 for appointment.