Patient Perspective on Testing

The LRG recently conducted a survey to better understand the types of testing GIST patients receive, such as mutational testing, circulating tumor DNA (ctDNA) testing, and genetic testing with the aim of learning how patients perceive and interpret these results. The goal of the survey was to identify knowledge gaps, highlight opportunities for patient education, and better inform the GIST community about the importance of comprehensive testing. This analysis reflects responses from 143 patients residing in the United States.

Most GIST patients undergo mutational testing, but awareness of ctDNA remains limited.

Key Takeaways

  • Mutational testing is common: 81% of GIST patients report receiving it, with KIT exon 11 being the most frequent mutation.
  • ctDNA awareness is low but interest is high: 79% had never heard of ctDNA, yet 76% believe it is very important once explained.
  • ctDNA is not for everyone: Tissue-based testing remains the gold standard, and ctDNA is still being studied; patients must meet certain criteria to benefit.
  • Patient confidence is moderate to strong: 42% of patients rated themselves a 4 out of 5 in understanding their mutational testing results.

Most respondents were LRG members (96%), and 72% are also enrolled in the LRG Patient Registry. The majority were women (64%), white, non-Hispanic (95%), and aged 65 or older (60%). At diagnosis, 64% reported a single tumor compared with 25% who were metastatic, and most patients currently reported being “no evidence of disease (NED)”.

Testing was widely reported, with 81% of participants receiving mutational testing. The most common mutation was KIT exon 11 (65%), followed by KIT exon 9 (12%), PDGFRA exon 18 (11%), and SDH-deficient GIST (9%). Awareness of ctDNA testing, however, was strikingly low—79% of patients had not heard of it prior to the survey and only 13% of those who received testing reported actually receiving ctDNA. Yet despite this lack of familiarity, 76% of patients said they believe ctDNA is a very important test.

ctDNA testing, often called a “liquid biopsy,” analyzes tumor DNA fragments circulating in the bloodstream. It offers the promise of non-invasive monitoring and may one day provide new insights into tumor mutations, treatment response, and recurrence. However, it is important to note that ctDNA is not appropriate for every patient. At this time, tissue-based testing remains the gold standard for diagnosing and guiding treatment in GIST. ctDNA is still being studied in research and clinical settings, and patients must meet certain criteria, such as having sufficient detectable tumor DNA, for the test to provide useful results.

When asked about their confidence in understanding mutational testing results, patients most often rated themselves a 4 on a 5-point scale (42%), suggesting strong but not complete confidence.

This survey highlights both the progress and the challenges in educating patients about available testing. While most GIST patients are receiving mutational testing and feel reasonably confident in understanding their results, awareness of ctDNA testing remains limited despite its promise. These findings reinforce the importance of continued patient education, advocacy, and access to cutting-edge tools, while reminding us that tissue-based testing remains the cornerstone of care today.

Why it matters for GIST:

  • Can sometimes identify tumor mutations without surgery
  • May offer a way to monitor treatment response or recurrence
  • Provides promising opportunities for more personalized care

Important to know:

ctDNA testing is not for everyone. At this time, tissue-based testing remains the standard for GIST. ctDNA is still being studied, and only certain patients meet the criteria for it to be useful.