New Sensitive Blood Test Detects, Characterizes and Monitors Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a fast-growing type of cancer that can rapidly spread to other parts of the body through a process called metastasis. Most small SCLC patients, representing 10-15% of all lung cancer cases, are diagnosed late with advanced metastatic disease and few survive beyond 1 to 2 years. However, of the minority of patients with SCLC who are diagnosed very early and have surgery, 6 out of 10 can live for 5 years or more. Now, doctors could one day diagnose and characterize early stage SCLC using a simple blood test.

Researchers at the University of Manchester (Manchester, UK) with a team at Memorial Sloan Kettering Cancer Center (MSKCC, New York, NY, USA) conducted a study focused on a new sensitive blood test to detect, characterize and monitor SCLC, the most aggressive form of lung cancer. The research team developed a new method to analyze blood samples and pick up specific DNA modifications called methylation that change early on in the growth of cancers. The team also developed a sophisticated computational method to assess which methylation modifications were present.

They focused on making their method sensitive enough to find methylation modifications in the very low levels of DNA shed from a patient’s tumor into the blood stream, known as called circulating tumor DNA (ctDNA). The test was sufficiently sensitive and accurate to detect methylation of ctDNA, even from patients whose tumors’ were diagnosed at the earliest stage. The standard treatment for SCLC is chemotherapy, but there are multiple types of SCLC that, recent studies suggest, would respond differently to a range of therapies. The new blood test could also classify which type of SCLC is affecting a patient, supporting the potential for more personalized treatment options.

“SCLC is a terrible disease, causing so much anguish to patients and their families. We think this blood test could be really useful in future clinical trials of new therapies to predict and monitor treatment responses,” said Professor Caroline Dive who led the study, which was funded by which was funded by the USA National Cancer Institute (NCI) and Cancer Research UK.

“A key advantage of blood-based molecular subtyping is that blood is much easier to collect and is able to circumvent the challenges often encountered in analyzing scant and often extensively necrotic tissue associated with tumor biopsies,” said Dr. Dominic Rothwell, who led the laboratory work. “Our study opens up the exciting possibility of detecting SCLC earlier and assigning patients to more personalized treatments.”

“To our knowledge, this is the first published study to show that DNA methylation analysis of a blood sample can identify the SCLC molecular subtypes,” added Prof Charles Rudin, Chief of Thoracic Oncology at Memorial Sloane Kettering Cancer Center who leads the global consortium that defined the different types of SCLC. “Though further validation is clearly now needed in a larger independent patient cohort, this blood test could one day assist clinicians in choosing better treatments for SCLC, which is currently notoriously difficult to manage.”

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