Biomarker testing underutilized in gastric, gastroesophageal junction cancers
Key takeaways:
- Biomarker testing appeared inconsistent, with rates not reflecting guidelines.
- Less than 25% of oncologists reported feeling “very” or “extremely” comfortable interpreting or applying biomarker test results.
Less than one-quarter of oncologists surveyed indicated that every one of their patients with advanced gastric or gastroesophageal junction cancers received biomarker testing consistent with practice guidelines.
“In the gastroesophageal cancer space, the last 5 years have really had a leap into biomarker-directed therapy or approvals for therapeutic options that have some biomarker that directs that decision, which is fundamentally a good thing and leads to better outcomes for patients,” Matthew Strickland, MD, medical oncologist at Massachusetts General Hospital and instructor in medicine at Harvard Medical School, told Healio.
“However, it’s not as easy as just having these approvals and options,” he added. “We need to make sure that each patient at the time of diagnosis has the appropriate biomarkers tested in order to truly make that therapeutic option even available, which can then lead to the better outcome.”
Biomarker-driven therapeutic strategies offer the opportunity for increased treatment precision for patients with gastric and gastroesophageal junction (G/GEJ) cancers, but only if oncologists perform biomarker testing.
The surge in biomarker-directed driven therapies over the past 5 years or so has helped establish new treatment options for patients, Strickland said.
However, the availability of new therapies have raised questions about which ones are best to use when, potentially complicating the treatment landscape for some oncologists, including those who practice in community settings.
Strickland and colleagues conducted a multicenter quality improvement initiative to evaluate current gaps in biomarker testing and practice patterns in multidisciplinary care for patients with G/GEJ cancers treated at community oncology centers.
Between May and August 2024, 60 oncology team members from five community practices in the U.S. completed surveys that assessed attitudes, knowledge, competence, practice patterns, challenges and gaps related to biomarker testing and multidisciplinary care.
Only 22% of providers reported that all of their patients with advanced G/GEJ cancer received biomarker testing.
Survey respondents indicated a majority of pathology reports include information about HER2 status (67%) and PD-L1 status (62%). However, less than half of pathology reports include information about mismatch repair status (48%), microsatellite instability (47%), tumor mutational burden (43%) and BRAF V600E (32%). Less than one-quarter of reports include information about NTRK1/2/3, RET, CLDN.18.2 and FGFR2, survey results showed.
Survey respondents identified three biomarkers that most often had to be requested if not included in the original pathology workup — PD-L1 (48%), TMB (32%) and BRAF p.V600E (32%).
“Because of a variety of challenges, the testing and subsequent decision-making is not as streamlined as it could be,” Strickland said. “This study specifically sheds light on some of those technical challenges, which underscores a pathway to addressing the gaps.”
The most common challenges to incorporating biomarker testing into practice included prioritizing testing for limited tissue (38%), determining whether to begin treatment prior to receipt of molecular testing results (35%) and optimizing specimen collection for molecular testing (27%).
Approximately one-fifth of providers (23%) reported they feel “very” or “extremely” comfortable interpreting and applying biomarker test results to treatment decision-making.
In addition to turnaround time and uncertainty interpreting results, providers cited challenges with inconsistent or infrequent multidisciplinary tumor boards. Some providers reported not participating in multidisciplinary tumor boards at all (12%), while others reported participating weekly (16%), once or twice a month (21%), every other month (12%) or less frequently (23%).
Providers indicated that improving the test ordering process (47%), decreasing testing turnaround time (42%) and standardizing panels for biomarker testing (40%) could help them implement biomarker testing.
“Everyone’s wish list is that biomarker testing and uptake would be 100% but, in the real world, we would hope that it would be somewhere north of 90%. That would be satisfactory,” Strickland told Healio. “We need implementation strategies to close the gap.”
According to Strickland, biomarker testing and therapeutic decision-making has evolved at a pace that has many oncologists, particularly those in community practices, unaware of recent advancements for certain tumor types.
“Some community practices, with providers that are very smart and very hard working, are seeing all kinds of tumor types, which is different than someone like me who 90% of the time sees one kind of cancer,” Strickland told Healio. “Sometimes an educational deficit can arise but, through partnership and educational programs, this gap can be closed pretty quickly.”
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Strickland M, et al. Abstract 385. Presented at: ASCO Gastrointestinal Cancers Symposium; Jan. 8-10, 2025; San Francisco.