New Technologies for Early Detection of Lung Cancer

Introduction:

Cancer is one of the most fatal diseases of recent times. Lung cancer is considered one of the most dangerous forms of cancer. It is regarded as the second most common form of cancer worldwide. The mortality rate in such cases is very high. Every year around 1.8 million people lose their life due to lung cancer. But an early diagnosis of such conditions can significantly increase the survival rate. Newer technologies have been utilized in detecting lung cancer at an early stage.

What Is Lung Cancer?

Abnormal cell division of the lung parenchyma is responsible for lung cancer. This excessive and abnormal proliferation of lungs is associated with the formation of dysplastic changes in the lung tissue (abnormal cell morphology, abnormal cellular function, and abnormal size and shape of the nucleus). The most common cause of lung cancer is smoking. Any form of smoking is associated with the ingestion of various carcinomatous substances. Various carcinogens present are polycyclic aromatic, hydrocarbons (PAHs), aromatic amines, N-nitrosamines, benzene, vinyl chloride, arsenic, and chromium in the smoke. These substances are responsible for DNA damage and change in cellular metabolic activity.

Occupational carcinogens like asbestos, beryllium, cadmium, bismuth, chloromethyl, ethers, chromium, nickel, radon, silica, and vinyl chloride are also associated with lung cancer. People working in mining fields or industrial areas are mostly affected by these carcinogens. Other than this indoor pollution from smoke and outdoor pollution is responsible for 17 percent of cancers in non-smokers. This type of pollution is also called secondhand smoke pollution. Genetic and familial factors are also associated with eight percent of cases of lung carcinoma. The most prominent gene associated with lung cancer is the RAS gene. Other than this mutation of tumor protein p53, MicroRNAs, and ROS1 is associated with the formation of lung cancers. Mutation of epidermal growth factor receptor (EGFR) is linked to the development of lung cancer in female non-smokers. Infections are also closely related to the formation of lung cancer. Bacterial infection caused by chlamydia pneumonia is associated with lung cancer. Apart from this viruses like the Epstein-Barr virus and human papillomavirus (HPV) is responsible for lung cancer.

The clinical manifestations of lung cancer are:

1. Difficulty in breathing even after normal activity and history of respiratory distress.
2. Heavy coughing, accompanied by a wheezing sound.
3. Presence of blood with coughing.
4. Chest pain and heaviness in the chest.
5. Weight loss.

What Are the Traditional Diagnostic Methods For Lung Cancers?

The diagnostic methods for lung cancers are:

1. Chest Radiographs:

This is the most traditional technique for cancer diagnosis. Clouding in the chest radiographs, and the presence of blackish or opaque spots is suggestive of lung pathology. Though confirmatory diagnosis is difficult to achieve through this procedure.

2. Computer-Based Tomograph (CT):

This is a radiation-based diagnostic procedure the first CT was used in 1973. Around 7 millisieverts (mSv) of radiation are used for the assessment of lung cancer. This can be used to identify arteriovenous fistulae, rounded atelectasis, fungus balls, mucoid impaction, and infarcts. Spiral and helical CT can be used to detect small nodules that can be missed between slices. The average slice thickness is 5 mm and it should not be more than 10 millimeters.

3. Magnetic Resonance Imaging (MRI):

In this technique, radio waves and magnetic fields are used to construct images of the internal organs. Soft tissue contrast and multiplanar analysis of the carcinoma can be diagnosed through this process. Also, soft tissue involvement of cancer and chest wall invasions are also can be diagnosed. But this procedure is relatively expensive and can not be done in patients with prosthetic heart valves. The blurring of the lymph nodes and overestimation of the size of the lymph nodes are potential side effects of such a procedure.

4. Positron Emission Tomography (PET): In this procedure, radioactive drugs are used to detect the metabolic activity of the cells and tissues. F-2-deoxy-D-glucose (FDG), a radiopharmaceutical drug is used for this purpose. This procedure is very useful for the defenestration of benign and malignant tumors. Also, metastasis and lymph node involvement can also be accessed in this technique.

What Are the New Technologies For Early Detection?

Different new diagnostic modalities are used for the early detection of lung cancer. These are:

1. Low-Dose Computed Tomography (LDCT): This is a single-slice spiral computed tomography technique. This method uses low radiation for good contrast imaging of air and lung tissues. This is helpful for the detection of different nodules present in lung cancer. Also, cardiovascular diseases and other lung diseases like COPD can be detected.
2. EBUS Using a Guide Sheet: In the past, the lung biopsy was done using the fluoroscopy technique. This new method is based on an endobronchial ultrasonography procedure. In this method, the ultrasound probe is covered with a sheet and inserted with the help of a bronchoscope. This method is helpful for the localization of cancerous lesions.
3. Sputum Cytology: The cytological analysis of the sputum has been identified as one of the most advanced procedures for the detection of early stages of lung cancer. In this procedure, Immunostaining with heterogeneous nuclear ribonuclear protein (hnRNP) is done for the detection of malignant changes in the DNA.
4. Pleural Fluid Cytology: In this procedure fluid within the lung is collected and accessed. This procedure is more accurate than sputum cytology.
5. Identification Of Biomarkers: Biomarkers are biological molecules that can be accessed for detection of the pathological conditions. BRAF, HER2, PTEN, EGFR, ALK, ROS, and KRAS are different biomarkers that are evaluated for detecting lung cancer. Biosensors are used to study biomarkers. These machines convert chemical signals into electronic responses.
6. Liquid Biopsy (LB): This is a new procedure in which the blood sample is collected and proteomic assessment of a wide variety of tumor-derived molecules such as circulating tumor cells circulating tumor DNA (ctDNA), tumor-derived extracellular vesicles (EVs) is done. This procedure helps to eliminate potential complexities of biopsy and radiological techniques. Molecular assessment helps to pinpoint the exact cancer disorder and its progression.

Conclusion:

Lung cancer is one of the most severe and lethal forms of cancer. Early detection of lung cancer can increase the term survival rate of the patients. New imaging methods and the identification of biomarkers are useful in detecting early-stage of lung cancer. Although the availability and affordability of these procedures are matter of concern.