Role Of Liquid Biopsies In Cancer Diagnosis: Detecting Tumour DNA In Blood

With the global cancer burden rising, the medical community strives to advance cancer diagnosis and management. The study projected the number of annual cancer cases to increase from almost 1.4 million in 2020 to 1.57 million by 2025. Early detection is crucial in improving treatment outcomes and reducing mortality rates. Amid this challenge, liquid biopsies have emerged as a promising minimally invasive diagnostic tool that has garnered significant interest in precision medicine.

Unlike traditional tissue biopsies, which are invasive and can offer limited snapshots of tumour composition, liquid biopsies involve analysing circulating tumour DNA (ctDNA) and other cancer-related biomarkers in the blood. This approach facilitates a more comprehensive and real-time understanding of the tumour’s genetic and epigenetic landscape, aiding in early diagnosis and monitoring disease progression.

Non-invasive and patient-friendly

One of the most significant advantages of liquid biopsies is their non-invasive nature. This method involves drawing blood, a simple and low-risk procedure, as opposed to traditional tissue biopsies that require surgical intervention. This ease of procedure means that liquid biopsies can be performed more frequently, providing ongoing monitoring of cancer evolution without subjecting patients to the discomfort and risks associated with repeated surgical biopsies.

Real-time monitoring

Liquid biopsies allow for the real-time monitoring of cancer, enabling clinicians to track the genetic profile of tumours as they evolve. This capability is crucial for identifying genetic mutations that may emerge over time, particularly those that confer resistance to current therapies. By capturing these changes early, clinicians can adjust treatment strategies proactively, potentially improving patient outcomes.

Comprehensive tumor profiling

Tumours are heterogeneous, often containing multiple subpopulations of cancer cells with distinct genetic profiles. Traditional biopsies may miss this complexity, especially if the biopsy samples a non-representative portion of the tumour. Liquid biopsies, on the other hand, sample ctDNA from various parts of the tumour and metastases, providing a more holistic view of cancer’s genetic landscape. This comprehensive profiling can guide the selection of targeted therapies and help monitor their effectiveness.

Impact on treatment

In treatment, liquid biopsies are invaluable for detecting treatment-resistant clones and other changes in tumour genetics. This information is critical for tailoring treatment plans to each patient’s unique tumour profile, embodying the principles of precision medicine.

Challenges and future directions

While liquid biopsies hold immense promise, they are not without challenges. The sensitivity and specificity of these tests must be continually refined to ensure accurate detection of ctDNA amidst the myriad of non-cancerous DNA in the bloodstream. As research progresses, it is anticipated that liquid biopsies will become an integral part of cancer care, supplementing traditional diagnostic methods and offering a window into the molecular intricacies of cancer.

Through ongoing advancements, liquid biopsies are poised to significantly enhance the surveillance and management of cancer patients, improving clinical outcomes and reducing mortality

The author is Head of Molecular Biology at the National Reference Lab, Oncquest Laboratories Limited, Gurugram

Dr. Vinay Bhatia

Guest Author Head of Molecular Biology at the National Reference Lab, Oncquest Laboratories Limited, Gurugram