AACR Annual Meeting 2026 Presidential Sessions Explore Cancer Interception and Prevention

June 5, 2026 by

Lillian L. Siu, MD, FAACR, has been researching potential new treatments for head and neck cancer and treating patients with this disease for over 30 years. Recently, she has turned her attention to intercepting cancer earlier. This new direction also elicited a desire to learn more about innovative approaches researchers are taking to stop cancer even earlier—by preventing it before it begins.

Siu, who is a senior medical oncologist and codirector of the Phase I Clinical Trials Program at the Princess Margaret Cancer Centre, University Health Network in Canada, recently wrapped up her tenure as President of the American Association for Cancer Research (AACR). But among her last acts as AACR President was devoting two sessions at the AACR Annual Meeting 2026, held April 17-22, to explore advances in the fields of cancer interception and prevention.

Presidential Address Examines Minimal Residual Disease and Cancer Interception

During her Presidential Address on “Mapping the Molecular Landscape of Head and Neck Cancer to Inform Pantumor Targeting,” Siu shared how her research into head and neck cancer could apply across solid tumors. One of the most recent examples of this has been a series of clinical trials examining the ability to detect minimal residual disease (MRD)—trace amounts of cancer left behind after treatment—and also to intercept cancer recurrence before it can grow and spread.

Lillian L. Siu, MD, FAACR, during the Presidential Address at the AACR Annual Meeting 2026.

Siu and her colleagues showed how this was possible in the MERIDIAN phase II trial, which monitored patients with high-risk locoregionally advanced head and neck squamous cell carcinoma for MRD following definitive treatment. If MRD was detected, patients were randomly assigned to either receive treatment with the investigational bispecific antibody rilvegostomig or to go into the observation arm. Out of 50 patients, two were confirmed to have MRD and one was randomly assigned to receive rilvegostomig. That patient has now been disease-free for 22 months, Siu said.

“Clearly, we have seen the hint that … we are able to intercept this disease,” Siu said. “If we are able to catch more of these cancers [earlier], we are possibly able to change the outcome of these patients.”

Siu and her colleagues recently re-opened this trial for another 50 patients with an amended protocol that includes a more sensitive assay that may better detect MRD. Additionally, they received funding to launch SHERLOCK (Study of High-Precision Evaluation of Molecular ResiduaL Disease through a PlatfOrm for Cancer TracKing and Interception) with the goal of creating the world’s largest MRD pancancer cohort by enrolling approximately 7,000 patients over four years. SHERLOCK will include arms for interception as well as treatment de-escalation.

To learn more about Siu’s Presidential Address, which also included her work on identifying dynamic biomarkers for treatment response, such as spatial transcriptomics and T-cell receptor repertoire, check out this article in AACR Annual Meeting News.

Presidential Select Symposium Zeroes in on Targeted Cancer Prevention

For the Presidential Select Symposium, Siu assembled a panel of experts to dive into the topic of “Targeting Stage 0: Precision-Based Prevention.”

“As a phase I trialist who treats a lot of patients in the advanced course of their disease … I really wanted to understand more about early cancer detection and prevention,” Siu said.

Sharon E. Plon, MD, PhD, of Baylor College of Medicine, discussed what she viewed as “exciting new opportunities for cancer prevention research in children.” She explained how there is growing interest in adding screening tests for cancer predisposition genes at birth. Currently, most newborns will get a heel stick to test for about 50 to 60 conditions, but this does not include cancer. However, a simulation model showed that screening newborns for these genes could decrease cancer deaths among those with cancer predisposition syndromes by 54%. 

Plon said several researchers, including herself, are exploring what it would take to implement genomic screening for newborns in public health systems and whether parents would be open to testing their babies for these predisposition genes.

Sharon E. Plon, MD, PhD, during the Presidential Select Symposium at the AACR Annual Meeting 2026.

Joann G. Elmore, MD, MPH, of the David Geffen School of Medicine at the University of California, Los Angeles, explored the role artificial intelligence (AI) can play in helping to improve early cancer detection, while also acknowledging some of the issues that still need to be resolved before it can be widely adopted for such purposes. For example, she pointed out studies that found accuracy errors when using computer-aided detection of breast cancer from mammograms as well as racial bias when using an AI-based tool to diagnose skin conditions.

But to better understand AI’s real-world impact in diagnosing cancers, Elmore and her colleagues are working to enroll 400,000 individuals in the Pragmatic Randomized Trial of AI for Screening Mammography (PRISM), which will randomly assign patients to an arm where mammograms will be interpreted by a radiologist on their own or an arm in which the radiologist will use an AI support tool. In both arms, the radiologist will make the final decision.

“While AI tools hold great potential, and I’m optimistic, they require rigorous evaluation,” she said.

John Burn, MD, of Newcastle University, and Mary (Nora) L. Disis, MD, of Fred Hutch Cancer Center, both provided updates relevant to individuals with Lynch syndrome, which is the most common cause of hereditary colorectal cancer. Burn discussed the latest results from the CaPP3 study, which has been exploring the use of aspirin to prevent cancer in people with Lynch syndrome. The study found that after eight years, low-dose aspirin (100 mg) resulted in the fewest cases of colorectal, bladder, and prostate cancers in individuals with Lynch syndrome compared with taking 600 mg or 300 mg doses of aspirin. Meanwhile, Disis discussed various preventive cancer vaccines, including a prophylactic vaccine to prevent colorectal cancer in individuals with Lynch syndrome by targeting frameshift mutations.

To learn more about the cancer prevention and interception strategies for Lynch syndrome presented by Burn and Disis, check out this blog post.