From detecting pre-dispositions to certain types of cancer, to determining treatment plans for hereditary conditions and identifying defective genes within diseased cells, genetic testing is a potentially life-saving oncology tool at Bumrungrad International Hospital.
An extended, 500-gene panel for investigating tumor tissue, added in April 2020, offers the possibility of novel therapies to those suffering with long-term diagnoses. Meanwhile, a new liquid biopsy panel focuses on cancer recurrence detection through plasma-extracted DNA. Genetics plays a crucial role in the fight against a disease that is one of the leading causes of death globally.
Screening for DNA Pre-Disposition
It is estimated that genetic mutations play a role in around 5-10% of cancers, with screening able to pick up on those most at risk from an inherited gene. These include breast, ovarian, colorectal, thyroid, prostate and endometrial cancer while others, such as lung cancer are far less likely to be genetically determined. Testing reveals where greater risks apply so that preventative measures can be taken or specific health monitoring put in place. A simple blood test, or germline test, enables an individual’s DNA to be decoded with sequences compared to normal ones to check for mutations or variations.
Genetic Guide to Hereditary Cancer Therapy
Understanding that a cancer has a genetic basis is important in terms of treatment too. The hereditary nature of the disease may result in different treatments and drugs being administered, while also taking into account variable prognostic risks such as recurrence rates. For example, breast cancer caused by a genetic mutation, may lead to treatment beyond surgery, chemotherapy and radiation that involves the removal of a patient’s non-affected breast, ovaries and fallopian tubes as a preventative measure. Having been diagnosed with such a cancer, a patient is by default in a higher risk group. As with screening, DNA is taken from a blood test and serves as a marker for life.
Somatic Testing to Extend Treatment Potential
Regardless of whether a cancer is hereditary or non-hereditary, genetic testing of cancerous tumor tissue, or somatic testing, can also aide in increasing medication options based on a patient’s gene profile. Genetic changes within cancer cells are used by specialists within Bumrungrad International Hospital’s dedicated Oncology Department to pinpoint where alternative, additional and advanced treatments are available. These complement rather than replace conventional therapies. This personalized medicine approach is particularly useful in advanced stages of a disease and due to the dynamic nature of the changes this type of profiling can be repeated.
The newly extended 500-gene panel can also aide in guiding therapy by determining how molecularly unstable a tumor is, (the total mutation burden). Lack of stability shows a greater variance in the mutation of an identified gene being more widespread within a tumor. An interesting advance in medical knowledge suggests that high instability tumors may be more likely to respond to immunotherapy. Finding variants in genetic pathways is key to Bumrungrad International Hospital’s commitment to finding advanced treatments.
This is a niche area, applying in the main to those patients who have battled multiple rounds of chemotherapy. However, for those reaching the end of their treatment options, somatic testing extends their potential for survival. Working alongside this, pharmacogenetics, offering personalized medication based on genes, can be applied within oncology to test cancer patients for genetic variations that impact the efficacy, tolerability and toxicity of conventional medicine too.
Preventing Recurrence with Plasma Investigation
In the case of advanced cancers, a blood test can flag-up whether tumor cells have become detached and are circulating in the bloodstream. This offers early detection of recurring cancer when tumors are not yet visible. In difficult-to-reach masses this type of liquid biopsy test, recently utilized at Bumrungrad International Hospital, means a patient does not have to undergo surgery to obtain a tissue sample. This is especially useful in cases where multiple testing is required, to avoid repeat surgeries. Although the extraction of small amount of DNA from the plasma is less invasive for the patient this procedure is less straightforward and more challenging to medical teams.
However, testing actual tissue gives more information and a a pathological examination of a tumor, such as the type of tissue and how aggressive the cancer is. For this reason, a liquid biopsy is considered an additional therapy when looking at the whole diagnostic and treatment journey.
Dr. Chanin Limwongse is a specialist in genetic medicine and pathology. His mission is to not only help in the fight to prevent cancer but to ensure treatments are as effective as possible. By better understanding cancer growth and treatment, genetic testing can offer cancer patients running out of options a possible life-line with less conventional treatment possibilities revealed as dictated by their genetic profile.