Newer, Less-Invasive Diagnostic Tools and the Role of Liquid Biopsy in 2026
Cancer diagnosis in India has long relied on tissue biopsy, imaging, and clinical suspicion, often after symptoms appear. While these remain the backbone of oncology practice, the limitations are obvious: invasive procedures, delays in diagnosis, difficulty accessing deep-seated tumors, and challenges in repeating biopsies over time.
Over the past few years, there has been a steady shift toward less-invasive diagnostic tools, and by 2026, this change is beginning to meaningfully influence cancer care in the Indian setting.
Advances in imaging such as high-resolution MRI, PET-CT with newer tracers, and improved endoscopic techniques have certainly reduced diagnostic morbidity. However, the most significant development has been the increasing clinical use of liquid biopsy—particularly circulating tumor DNA (ctDNA) analysis from blood samples.
Understanding liquid biopsy in simple terms
Liquid biopsy refers to the detection of tumor-derived material in body fluids, most commonly blood. This includes circulating tumor DNA, circulating tumor cells, RNA fragments, and extracellular vesicles. Among these, ctDNA has emerged as the most clinically relevant and widely used component.
Cancer cells shed small fragments of DNA into the bloodstream. These fragments carry tumor-specific genetic alterations and reflect the molecular profile of the disease. Unlike tissue biopsy, ctDNA testing does not require surgery, anesthesia, or hospitalization. More importantly, because ctDNA has a short half-life, it provides a real-time snapshot of tumor biology.
Where does ctDNA fit in Indian oncology practice in 2026?
In 2026, liquid biopsy is no longer a novelty in India’s larger cancer centres. Its role is evolving across several key areas.
1. Early detection and screening in high-risk individuals
While population-level cancer screening in India still relies on conventional methods—such as breast examination, mammography, Pap smears, and colonoscopy—ctDNA-based tests are increasingly being explored for high-risk groups. This includes individuals with strong family histories, hereditary cancer syndromes, or previous cancers.
Multi-cancer early detection blood tests are showing promise, particularly for cancers where India lacks effective screening programs, such as pancreatic, ovarian, and biliary tract cancers. However, in the Indian context, cost, accessibility, and the risk of over-diagnosis mean that ctDNA screening is best used selectively rather than universally.
2. Detection of minimal residual disease (MRD)
One of the most impactful applications of ctDNA in India has been in detecting minimal residual disease after curative-intent treatment. Patients who appear disease-free on scans may still harbor microscopic cancer that eventually leads to relapse.
In colorectal, breast, lung, and hematologic malignancies, ctDNA positivity after surgery or chemoradiation is now recognized as a strong predictor of recurrence. In 2026, Indian oncologists increasingly use ctDNA results to stratify risk, guide closer surveillance, or consider additional systemic therapy in selected patients.
3. Molecular profiling when tissue is inadequate
Obtaining adequate tissue remains a challenge in many Indian patients, especially those with advanced disease, poor performance status, or tumors in difficult anatomical locations. Liquid biopsy has become a practical alternative when tissue biopsy is unsafe or yields insufficient material for molecular testing.
For lung cancer, breast cancer, colorectal cancer, and several rare malignancies, ctDNA testing is now routinely used to identify actionable mutations and guide targeted therapy, reducing delays in treatment initiation.
4. Monitoring treatment response and resistance
Repeated tissue biopsies are neither feasible nor patient-friendly. Serial ctDNA testing allows clinicians to monitor response to therapy and detect emerging resistance mutations. Rising ctDNA levels often precede radiological progression, offering an early warning signal.
In India, this has particular value in patients receiving expensive targeted therapies, where early identification of resistance can help avoid ineffective treatment and unnecessary financial burden.
Practical limitations that cannot be ignored
Despite its advantages, liquid biopsy is not without limitations. Tumors with low burden or low shedding may result in false-negative results. Clonal hematopoiesis—common in older individuals—can cause false positives if not carefully interpreted. Standardization across laboratories and cost remain major barriers, especially outside metro cities.
Most importantly, ctDNA testing must always be interpreted in clinical context. It complements but does not replace imaging, pathology, and sound clinical judgment.
The road ahead
The future of cancer diagnostics in India lies in integration rather than replacement. Tissue biopsy remains essential, but liquid biopsy has added a powerful, patient-friendly layer to our diagnostic toolkit. By 2026, ctDNA has found its role—not as a universal screening test, but as a precision tool used thoughtfully for early detection in selected patients, for MRD assessment, and for dynamic disease monitoring.
As access improves and costs decline, liquid biopsy is likely to play an even greater role in making cancer care in India more personalized, timely, and less invasive—while keeping the patient firmly at the center of decision-making.
Disclaimer: The views expressed in this article are of the author and not of Health Dialogues. The Editorial/Content team of Health Dialogues has not contributed to the writing/editing/packaging of this article.
