Imagine if a blood test could show whether a tumor is responding to treatment, without the need for invasive and sometimes painful biopsies. Imagine if it could give doctors an early warning that a drug has stopped working, and offer valuable information about the next one to try. Thanks to our research, these tests are now becoming a reality.

No two cancers are alike. Their genetic make-up—their DNA code—varies from person to person and can change over time. But a cancer’s specific genetics can have a big impact on how it responds to treatment.

Our researchers are developing new blood tests to stay one step ahead of this process, allowing us to predict which available treatments will give the most benefit to patients.

Quicker, simpler, less invasive

Known as liquid biopsies, the tests are already routinely used in clinical trials, including those we run with our partner hospital, The Royal Marsden NHS Foundation Trust.

Because they don’t require a tissue sample, liquid biopsies are quicker, simpler, and far less invasive than a traditional biopsy. Instead, the tests analyze cancer DNA circulating in the blood to determine whether a drug is working.

This also means they can pick up DNA from multiple tumors throughout the body, giving a more comprehensive picture than has previously been possible.

Drug resistance identified earlier

Dr. Gerhardt Attard, Clinician Scientist at The Institute of Cancer Research, London, and Consultant at The Royal Marsden, has developed a new liquid biopsy to identify patients with advanced prostate cancer who are unlikely to respond to abiraterone—the standard treatment for the disease.

Discovered at the ICR, abiraterone has given thousands of patients valuable extra months of life, while causing fewer side effects than chemotherapy. Unfortunately, some patients don’t respond to it, and need to be given a different treatment.

Dr. Attard’s research using the liquid biopsy showed that patients with certain changes to their androgen receptor gene, such as mutations within the gene and extra copies of the gene itself, were much less likely to respond to abiraterone.

The test was also able to spot drug resistance several months before patients showed signs that their disease was progressing once again.

“Our liquid biopsy isolates and analyzes tumor DNA from the blood to identify the key genetic changes that drive abiraterone resistance,” explains Dr. Attard. “In the future, the test could tell us in real time which patients have stopped benefiting from the drug, and allow us to offer other treatments much more quickly.

“We are now beginning a new clinical trial, involving up to 600 men, in which we aim to show that patients who test positive for these genetic mutations get significantly greater benefit from chemotherapy compared to abiraterone. If the clinical trial has positive results, we could see the liquid biopsy adopted into more routine clinical practice in prostate cancer.”