Personalizing Lung Cancer: Why Testing Matters

If you are facing lung cancer, or know someone who is, you’ve likely heard doctors or nurses mention words like targeted therapy, genetic mutation or diagnostic testing. These buzzwords all refer to personalized medicine – sometimes called “precision” medicine – a developing area of cancer research that enables oncologists to tailor treatments based on individual tumor characteristics.

How do they do that? Just as each patient has a unique personality, so does each tumor – tumors are driven by unique sets of genes that have their own mutations and alterations, often called biomarkers. The word “biomarker” refers to any molecule in the body that can be measured or identified to understand some aspect of a patient’s tumor. When doctors identify the unique thumbprint of a tumor, through biomarker testing, also referred to as “molecular testing” or “genetic testing,” they can often prescribe medicines that are designed to target those specific traits.

If you or a loved one has been diagnosed with lung cancer – whether recently or years ago – it’s important to talk with your doctor about whether biomarker testing may be appropriate to determine if personalized treatment is an option.

Lung cancer is not one disease

Personalized treatments are available for a variety of cancers, but for lung cancer treatment, especially, one size does not fit all. There are several types of lung cancer – about 10 to 15 percent are small cell lung cancers and about 80 to 85 percent are non-small cell lung cancers (NSCLC). 

Once a doctor has determined if a lung cancer is NSCLC, there are three main subtypes – including adenocarcinoma, squamous cell carcinoma and large cell carcinoma. Beyond these broad subtypes, doctors can also identify more specific mutations, or biomarkers, which can determine the best course of treatment. An estimated 60 percent of adenocarcinoma and 80 percent of squamous cell carcinoma are associated with a known mutation, such as the epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK) rearrangements, PIK3CA and KRAS mutations, which doctors can often identify when a patient is first diagnosed, and treat accordingly.

Importantly, biomarker testing isn’t only for newly diagnosed patients. EGFR mutation-positive NSCLC is smart – it changes and evolves over time, and often develops new mutations – especially as it acquires resistance to first-line targeted therapies. Identifying these new, or secondary, mutations can help doctors to determine appropriate management when the current treatment is no longer working. For example, approximately 60 percent of patients with the EGFR mutation will develop resistance to their first-line targeted therapy over time, and their cancer will progress. If a patient is re-tested, their doctor may then look for the T790M mutation, which is observed in nearly two out of three tumors that progress after first-line targeted therapy. Secondary testing results can provide valuable information and help guide that patient’s next steps.

Testing counts – more now than ever

Personalized medicine and biomarker testing are not new. In fact, targeted lung cancer therapies have existed for more than a decade – and with every passing year, our understanding of cancer genetics is becoming increasingly sophisticated, allowing doctors to more effectively identify the right medicine for the right patients at the right time. This progress makes testing more important than ever before – at diagnosis, and again if cancer progresses.

The most common way to test for biomarkers is through a tissue biopsy – the surgical removal of tissues for examination by a pathologist, which will then be studied under a microscope or tested further to identify biomarkers.

For some patients, a “liquid biopsy” –  or simply, a blood-based test – is available to identify specific mutations. This is a relatively recent development, and is particularly helpful for patients who do not qualify for more invasive biopsies. These work by analyzing tiny pieces of tumor DNA, called ctDNA, that have been shed into the blood stream.

The bottom line – biomarker testing has changed treatment decision making

When diagnosed with lung cancer, testing is critical – but all too often, patients are not tested for biomarkers that could identify them as candidates for targeted treatment options. If you or a loved one have been diagnosed with lung cancer, or if you are in the advanced stages of the disease and have progressed, talk with your doctor about the latest biomarker testing to help further personalize your treatment path.

To learn more about lung cancer mutations and why they matter, visit  

To download an infographic about lung cancer testing, click here.