Lung Cancer Diagnosis

A diagnosis of lung cancer marks the beginning of a challenging journey. It is important to approach this process with a clear understanding of the steps involved and the potential for successful treatment. In recent years, significant advancements in diagnostic techniques have enabled earlier detection and more precise staging of lung cancer, which has led to improved outcomes for many patients.

 

The diagnostic journey typically begins with thoroughly evaluating a patient’s medical history, risk factors, and symptoms. This is followed by a physical examination and a series of imaging tests, which may include chest X-rays, CT scans, PET scans, and MRI scans. These non-invasive tests provide detailed visualisations of the lungs and can help identify suspicious areas requiring further investigation.

 

This comprehensive guide aims to clarify the tests and procedures used to diagnose lung cancer, providing a roadmap for what to expect and highlighting the reasons for optimism in the face of this serious disease.

 

Diagnosing Lung Cancer: A Step-by-Step Approach

The process of diagnosing lung cancer involves a series of tests and procedures designed to identify the presence and extent of the disease accurately. The diagnostic journey typically begins with a patient presenting with symptoms or being identified as high-risk through screening. From there, a multidisciplinary team of healthcare professionals works together to gather the necessary information to make a definitive diagnosis and develop an appropriate treatment plan.

 

Medical History and Physical Examination

The first step in the diagnostic process begins with evaluating the patient’s medical history and current symptoms. The doctor will enquire about risk factors such as smoking history, exposure to environmental toxins, and family history of lung cancer. They will also perform a physical examination, assessing for signs such as lumps in the neck, difficulty breathing, or chest pain.

 

Imaging Tests

Imaging tests play a crucial role in diagnosing lung cancer by providing detailed visualisations of the lungs and surrounding structures. Common imaging tests include:

 

• Chest X-ray: A simple, non-invasive test that can reveal suspicious lung areas
• Computed Tomography (CT) Scan: A more detailed imaging test that uses X-rays and computer technology to create cross-sectional images of the lungs.
• Magnetic Resonance Imaging (MRI): An advanced imaging technique that uses magnetic fields and radio waves to produce detailed images of soft tissues in the body. MRI is used predominantly to screen the Brain for metastasis in patients at with a high risk for brain metastasis.
• Positron Emission Tomography (PET) Scan: A specialised imaging test that uses a radioactive tracer to identify areas of increased metabolic activity, which can be indicative of cancer.

 

Biopsy

If imaging tests reveal a suspicious lung area, the next step is typically a biopsy. This involves obtaining a tissue sample from the abnormal growth followed by microscopic examination by a pathologist. Several biopsy techniques may be used, depending on the location and size of the lesion:

 

• Bronchoscopy: A thin, flexible tube with a camera is inserted through the nose or mouth and into the lungs, allowing for direct visualisation and tissue sampling.
• Percutaneous Needle Biopsy: A needle is inserted through the chest wall to remove a small tissue sample from the lungs.
• Thoracoscopy: Small incisions are made in the chest, allowing for the insertion of a camera-equipped tube to visualise and biopsy the lungs.

 

Advanced Diagnostic Techniques

In addition to traditional diagnostic methods, some leading cancer centres offer advanced techniques for a more precise evaluation of lung cancer:

 

• Endobronchial Ultrasound (EBUS): A specialised bronchoscopy procedure that uses ultrasound to visualise and biopsy lymph nodes and other structures in the chest.
• Navigational Bronchoscopy: A technique that uses GPS-like technology to guide bronchoscopic tools to small, hard-to-reach lung lesions for biopsy.

 

In India, some advanced hospitals, like Apollo Cancer Centres, also offer specialised tests such as PET-CT scans or endobronchial ultrasound-guided biopsy (EBUS) to understand the stage of lung cancer.

 

However, the diagnostic process may vary depending on the availability of resources and expertise in different healthcare settings. So, it is suggested to consult a qualified healthcare professional for an accurate diagnosis and appropriate treatment plan for lung cancer.

 

What is the Most Commonly Diagnosed Lung Cancer?

Lung cancer is broadly categorised into two main types based on the appearance of the cancer cells under a microscope: small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). Understanding the differences between these two types is crucial, as they have distinct characteristics, prognoses, and treatment approaches.

 

Small Cell Lung Cancer (SCLC)

SCLC, also known as oat cell cancer, accounts for approximately 10-15% of all lung cancer cases. The rapid growth and spread of small, round cancer cells characterise this aggressive form of lung cancer. SCLC is strongly associated with a history of heavy smoking and exposure to environmental toxins like radon gas.

 

SCLC is classified into two stages:

• Limited stage: Cancer is confined to one lung and nearby lymph nodes.
• Extensive stage: Cancer has spread beyond the primary lung to other body parts.

 

Due to its rapid growth and spread, SCLC is often diagnosed at an advanced stage. Symptoms may include:

• Persistent cough,
• Shortness of breath,
• Chest pain,
• Fatigue
• Unintentional weight loss.

 

In some cases, SCLC may also cause symptoms related to paraneoplastic syndromes, such as syndrome of inappropriate antidiuretic hormone (SIADH) or Lambert-Eaton myasthenic syndrome (LEMS).

 

The prognosis for SCLC is generally poor, with a five-year survival rate of around 7%. However, early detection and aggressive treatment, typically involving a combination of chemotherapy and radiation therapy, can improve outcomes and potentially lead to long-term survival in some cases.

 

Non-Small Cell Lung Cancer (NSCLC)

NSCLC is the most common type of lung cancer, accounting for approximately 85-90% of all cases. NSCLC grows and spreads more slowly than SCLC and is classified into three main subtypes based on the type of cells that make up the tumour:

 

• Adenocarcinoma: The most common subtype of NSCLC, often found in the outer regions of the lungs and more common in non-smokers and younger individuals.
• Squamous cell carcinoma: Typically arises in the central chest area in the bronchi and is strongly associated with a history of smoking.
• Large cell carcinoma: This is a less common subtype characterised by large, abnormal-looking cells that can occur in any part of the lung.

 

Symptoms of NSCLC are similar to those of SCLC and may include persistent cough, shortness of breath, chest pain, fatigue, and unintentional weight loss. Depending on the location and size of the tumour, patients may also experience coughing up blood, hoarseness, and difficulty swallowing.

 

Treatment for NSCLC depends on the stage and subtype of the cancer and the patient’s overall health. Early-stage NSCLC may be treated with surgery, while advanced-stage disease may require a combination of chemotherapy, radiation therapy, targeted therapy, and immunotherapy.

 

Advancements in targeted therapies and immunotherapies have significantly improved outcomes for patients with specific genetic mutations or biomarkers, such as EGFR, ALK, ROS1, and PD-L1. Comprehensive molecular testing of NSCLC tumours has become essential to the diagnostic process, guiding personalised treatment decisions.

 

In addition to traditional treatment modalities, proton therapy has emerged as a promising option for some patients with lung cancer. Proton therapy is a type of radiation therapy that uses high-energy proton beams to target and destroy cancer cells with precision, minimising damage to surrounding healthy tissues.

 

Proton therapy may be particularly beneficial for patients with early-stage NSCLC, as it can deliver a high dose of radiation to the tumour while sparing nearby critical structures such as the heart, esophagus, and spinal cord. This targeted approach may reduce the risk of side effects and improve the quality of life for patients undergoing treatment.

 

Conclusion

The path forward after a lung cancer diagnosis can feel overwhelming, but you are not alone. Have open conversations with your care team about your diagnosis, treatment options, and any concerns. With the right information, support, and a collaborative partnership with your healthcare providers, you can navigate this challenging time with clarity and hope.