Timing Matters, and Liquid is Part of the Future

In the last 20 years we have seen a seismic shift from the view of NSCLC as a single disease to that of a suite of cancers caused by various oncogenic drivers and specific genetic mutations. Diagnosis has evolved from reliance on histology to genomic-based subtyping, which has guided the development of targeted therapies.

The response rates to such therapies at first line are truly staggering – 60 to 80 percent or more for some EGFR, ALK, and RET targeted therapies (1, 2, 3). Five-year overall survival rates are also encouraging with these targeted therapies – up to 60 percent of patients with ALK inhibitors, for example (4). The need to ensure that all eligible patients are identified and offered this targeted first-line treatment as quickly as possible is clear.

The ESMO guidelines support this, recommending testing for all targetable oncogenic drivers is performed for all advanced NSCLC cases ahead of first-line treatment (5). Ideally, targeted NGS panels, covering both DNA and RNA alterations, should be used for this (5).

But is this feasible in practice? In order to review the current and future landscape of genomic profiling in NSCLC, our symposium at ELCC recreated a molecular tumor board for multidisciplinary perspectives. Our speakers were Fernando Lopez- Rios (pathologist from Spain), Francesco Passiglia (medical oncologist from Italy) and Morten Grauslund (molecular biologist from Denmark). Here is what they told us.

What to test
 

The ESMO guidelines recommend testing for the following oncogenic drivers at first line (5):

The oncologist’s perspective – Biomarker testing shortfalls
 

Sadly, the reality is that the availability of biomarker testing across Europe is highly variable. It is estimated that half of patients with advanced NSCLC are missing the opportunity to benefit from personalized medicine due to gaps in biomarker testing and adequacy (6). Barriers such as no biopsy offered, insufficient samples, tests not ordered, and inconclusive or false negative results are all too prevalent (6). In many cases, turnaround times (TAT) for test results are too lengthy, resulting in disease progression or death of the patient.

Access to NGS testing is also less than ideal. Most patients still receive only single biomarker testing in the real world. Even in the US, less than 50 percent of eligible patients receive multibiomarker NGS testing (7). This can have a detrimental effect on overall survival rates.

Even where NGS testing is available, outsourcing of the service can result in TAT of several weeks. Many patients simply cannot wait this long to start treatment, meaning they may receive less effective therapies, or their condition may advance too far for help. The solution is clear – wider adoption of in-house rapid NGS testing to decrease diagnostic TAT to days rather than weeks.

Finally, given the complexity of interpreting genetic alteration data, assembling all the relevant expertise onto tumor boards is key to timely reporting of genomic profiling in NSCLC.

The pathologist’s perspective – The future is liquid
 

Studies have shown that overall survival of advanced NSCLC patients improves when broad genomic profiling is performed prior to first-line therapy (8). Integration of biomarker testing into the diagnostic workup is crucial for informed decision making throughout the patient journey.

What can be done to improve accessibility to, and speed of, genomic profiling? With the joint attributes of convenience and speed, wider adoption of liquid biopsy could help break down some of the barriers to multibiomarker reports being available at the time of the treatment decisions (9). Not to mention it is the preferred testing option for the majority of patients. However, workflows for liquid biopsies are rarely optimized, and it is necessary to explore ways to improve the diagnostic TAT with these methods. There are two main ways to achieve this – lean workflows and reflex testing strategies.

A lean workflow starts with efficient blood collection, which, unfortunately, is not yet standardized. Ideally, this would involve two 10 mL samples of carefully drawn blood in EDTA tubes or preservation tubes that are filled to the top. At room temperature, when using EDTA tubes, there should be a maximum of 2 hours between blood collection/ stabilization and blood separation. Refrigeration should be used for longer time lapses, up to maximum of 24 hours.

Reflex testing means performing genomic profiling for all NSCLC diagnosed patients. Truly effective reflex testing would require a change of practice from seeing liquid biopsy as a last resort to using it as a complementary approach to tissue biopsies, or possibly even as plasma first approach (10, 11).

And finally, how should interpretation of broad genomic profiling be handled? Due to its sheer complexity, more and more institutions are now assembling intra-laboratory molecular tumor boards. By bringing together technicians, pathologists, molecular biologists, and clinicians, analysis of the various test results can be most effectively integrated. Experience shows that effective communication has a positive effect on overall survival of patients.

The molecular biologist’s experience – Ultra-fast in-house NGS testing is key
 

In Denmark, the recommended TAT for NSCLC diagnostic testing – including imaging, biopsy, histopathology and biomarker testing – is 24 days. A team at Rigshospitalet in Copenhagen have been studying the effect of in-house NGS testing on TAT.

The team used the Oncomine™ Dx Express Test on the Genexus Integrated Sequencer Dx System, running daily from Monday to Friday, for tests ordered by the pathologists before 12 noon. Molecular results were integrated with histopathology results into one report for the clinician. The study of 544 DNA and 490 RNA samples revealed that their TAT – from test ordered to results reported – averaged just 4 working days.

What’s more, the study revealed that the testing workflow time was reduced from 4 days (with Sanger sequencing) to around 20 hours. This is based on running six samples, starting from DNA and RNA, from library preparation to sequencing and results.

The Oncomine Dx Express Test covers the majority of actionable biomarkers recommended in the ESMO guidelines. Conclusive test results were reported for 96 percent of DNA and 99 percent of RNA analyses. Study results showed high performance for both DNA and RNA based biomarkers, and robust assays even with sparse samples. Testing success rates of 95–98 percent were reported, reducing potential re-biopsies and delays.

And was the Genexus Dx System user friendly? Well, whilst lab technicians reported it can be challenging to optimize the chip utilization, they also experienced significantly reduced hands-on time with the Genexus Dx System and, of course, shorter TAT compared to previous systems.

What needs to change?
 

Tissue biopsy is still regarded as the gold standard for molecular tests, and a cultural shift will be needed before liquid biopsies are widely adopted. That will only be achieved via education. The affordability of liquid biopsies must also be considered. Many institutions currently have insufficient funding to perform both tests.

Similarly, the business case for in-house NGS will need to be strong in order to justify the investment – studies such as the one in Copenhagen will be useful in helping this cause.

Ultimately, with so many patients missing out on effective treatments and considering the overall costs of care, including treatment, can we afford not to invest in rapid TAT and liquid biopsy testing adoption?