Lung Cancer

Lung cancer does not show any visible symptoms until it has grown and spread considerably. A nodule in the pulmonary area could grow uninterrupted for a considerable period of time and could spread outside of the lung before it causes symptoms.⁴

Lung cancer has been categorized into two major histological subtypes as non-small cell lung cancers (NSCLCs) and small cell lung cancer (SCLC).

NSCLCs account for approximately 85% of all lung cancers.⁵ These are further characterized into different types based on their anatomical and molecular attributes:

• Adenocarcinoma
• Squamous cell carcinoma
• Large cell carcinoma
• Carcinoma not otherwise specified

SCLC accounts for approximately 15% of all lung cancers. It usually originates in the bronchi of the lungs and is often associated with smoking.⁶

Presence of specific mutations can determine what kind of treatment options may be suitable for therapy. For example, rearrangements of the anaplastic lymphoma kinase (ALK) gene serve as biomarkers for cancer. FDA- approved ALK assays are available for testing for ALK protein in NSCLC metastatic tumors, which help in making immediate treatment decisions. The NCCN guidelines recommend molecular testing for oncogenes, such as ALK.⁷ The guidelines recommend ALK (D5F3) assay as a standalone IHC test, not requiring confirmation by FISH.

The initial assessment is conducted with imaging with chest X-rays or using a CT scan, followed by histological confirmation using a biopsy sample.

Hematoxylin and Eosin (H&E) staining is used for histological classification and immunohistochemistry (IHC) using monoclonal antibodies is used for subtyping.

Immunotherapy has revolutionized cancer treatment in recent years. This novel therapy bypasses traditional routes of treatment, which are directed against tumor cells. Immunotherapy works by indirectly stimulating the immune system to eliminate tumor cells through negative regulators of T-cell function, such as immune checkpoint inhibitors. Immune checkpoint inhibitors, such as Programmed death ligand (PD-L1) have been approved for use with NSCLC. However, not all patients respond to these inhibitors uniformly and immunotherapy could have unintended side effects and could prove expensive.⁸ Guiding assays, such as PD-L1 predictive assays, aid healthcare providers and labs in determining if a patient would respond to a specific therapy (for example, aterzolizumab for NSCLC). They can also provide insights into a patient’s potential overall survival.

During the course of treatment, secondary mutations might arise and affect the responsiveness of patients. For example, presence of specific mutations in EGFR can alter how the response for treatment with tyrosine kinase inhibitors would be.⁹ FDA-approved EGFR mutation tests can detect specific EGFR mutations both from tissue and liquid biopsy samples and identify patients who would respond best to tyrosine kinase inhibitor treatment. This real-time PCR-based test can also be used for tumor monitoring during the course of treatment.

Roche offers a full range of products for all stages, from initial assessment, diagnosis and prediction to monitoring of lung cancer.

Since lung cancer is complicated and benign conditions and metastases from other primary tumors can mimic lung cancer on imaging, several methods are used, often in tandem, to confirm diagnoses.