EORTC at ESMO 2026: New findings and ongoing studies

Comparing treatment approaches in early-stage head and neck cancer

Early-stage head and neck cancers, including oropharyngeal (OP), supraglottic (SG), and hypopharyngeal (HP) squamous cell carcinoma (SCC), can be effectively treated with either transoral surgery (TOS) or dysphagia-optimised intensity-modulated radiotherapy (DO-IMRT). However, randomised evidence directly comparing the impact of these approaches on swallowing function has been limited.

Dr Christian Simon presented results from the Phase III EORTC-NCRI-GORTEC-IAG-KHT 1420 “Best-of” trial¹, which randomised 86 patients to either TOS or DO-IMRT and assessed swallowing function 12 months after treatment using the MD Anderson Dysphagia Inventory (MDADI). No significant difference in swallowing outcomes was observed between the two groups. Mean MDADI scores were 83 after TOS and 86 after DO-IMRT. Importantly, no patient required a feeding tube at 12 months.
Among patients assigned to surgery, 36% subsequently received adjuvant radiotherapy, including 19% who also received chemotherapy. In the radiotherapy arm, 25% of patients did not start treatment. One quality-of-life endpoint, dry mouth/sticky saliva, was worse in the DO-IMRT group during the first six months after treatment.

After two years, event-free survival was 84% in the TOS group and 72% in the DO-IMRT group. Overall survival was very high in both groups, at 97% following TOS and 100% following DO-IMRT.

Grade 3 or higher treatment-related adverse events occurred in 21% of patients in each group, with no treatment-related deaths. Oral mucositis and dry mouth were more frequent after DO-IMRT, whereas surgery carried specific risks such as bleeding and fistula formation.

The researchers concluded that there was no evidence of a difference in swallowing function at 12 months between TOS and DO-IMRT. Given that a third of surgically treated patients required adjuvant radiotherapy and that greater mucosal and salivary toxicity signals were observed after DO-IMRT, these findings, together with patient preferences, can help inform shared decision-making and support individualised treatment selection based on tumour characteristics, expected toxicity, and patient priorities.

Long-term outcomes after pembrolizumab in early-stage lung cancer

The final analysis of the PEARLS/KEYNOTE-091 study on the effect of the immunotherapy pembrolizumab in patients who had had complete surgical resection of stage IB to IIIA non-small cell lung cancer (NSCLC) tumours was presented by Dr Mary O’Brien.

This prespecified final overall-survival analysis was triggered by the 10 year time point from the first participant randomised, as there were few survival events. The sub group who received chemotherapy formed the largest cohort in the study. Earlier results from the study, which involved 1177 patients, showed that pembrolizumab delayed a recurrence of their cancer. This previously demonstrated disease-free survival benefit was maintained with longer follow-up of approximately 7 years. In this subgroup, median disease-free survival was 58.7 months with pembrolizumab versus 39.1 months with placebo (HR, 0.80; 95% CI, 0.68–0.94).

Although overall survival, a secondary endpoint, was not significantly improved at this analysis with pembrolizumab in NSCLC patients post surgery, its use improved the secondary endpoint of lung cancer specific survival. There was no deterioration in quality of life in the patients who received pembrolizumab compared to placebo.

¹ https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal/session/calendar?q=1420#presentation-abstract-67361297365434https://cslide.ctimeetingtech.com/esmo2025/attendee/confcal/presentation/list?q=2279MO#presentation-abstract-6780559840300

² https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal/session/calendar/2026-10-26?q=PEARLS#presentation-abstract-72932072962031 

Using ctDNA to guide treatment in early breast cancer

In patients with endocrine receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative early breast cancer, testing for circulating tumour DNA (ctDNA) may help identify breast cancer patients at risk of relapse at an early stage, before any signs can be detected by imaging. This would allow clinicians to use endocrine therapy early, when the burden of disease is still very small. The ongoing phase Ill EORTC 2129 TREAT ctDNA trial is evaluating whether an early switch to the endocrine therapy elacestrant can delay or prevent metastatic relapse in patients with negative imaging, but for whom relapse has been detected by ctDNA testing.

Teck Long King³ presented results from the first patients to undergo ctDNA surveillance. Among 882 patients being monitored, 56 patients were positive for ctDNA, 78.6% of whom were detected at the first test. Compared with those who remained under surveillance, those who tested positive for ctDNA were more likely to have more lymph nodes involved. Nodal burden may help enrich ctDNA-surveillance populations for ctDNA-guided trials in patients with ER-positive/HER2-negative early breast cancer, the researcher says. Informed by these findings, the protocol was subsequently amended to prioritise enrolment to patients with four or more positive lymph nodes. The clinical benefit of ctDNA-guided treatment escalation is currently being evaluated in the randomised TREAT ctDNA trial.

³ https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal_1/presentation/list?q=King#presentation-abstract-188112153980

A new study in high-risk uveal melanoma

Dr Paul Nathan presented the ATOM trial EORTC-2022-MG⁴ of the immunotherapy Tebentafusp in patients with high-risk uveal melanoma (UM). UM is a rare malignancy with a high risk of distant recurrence, and more than half of all patients at high risk will develop metastatic disease. In an earlier Phase III trial in the metastatic setting, patients treated with Tebentafusp had considerably increased overall survival, even after five years, and it is now the first line standard of care.

The ATOM trial is investigating whether giving Tebentafusp earlier, before any spread of the cancer is observable, could destroy any undetectable cancer cells and thus improve the longer-term outcome for UM patients. They will be randomised to two groups; those who will receive active treatment for up to six months, and those who will have no treatment but who will be monitored regularly. A total of 290 patients will be enrolled and will be followed until death or the end of the study, whichever occurs first. Recruitment started in November 2025, and the participating countries are currently Belgium, France, Germany, Italy, The Netherlands, Poland, Spain, the United Kingdom; Ireland, Norway, Sweden, and the United States, with more countries expected to join later.

⁴ https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal_1/presentation/list?q=paul+nathan#presentation-abstract-83371082514736

Brain metastases in gastroesophageal cancer survey/ How are brain metastases managed in gastroesophageal cancer?

Although there are internationally-accepted treatment guidelines for brain metastases (BMs) from solid tumours, there are none specifically for those arising from gastroesophageal cancer, and existing recommendations do not distinguish between isolated BMs and BMs that have spread to other parts of the body (extracranial metastases or ECMs). Dr Hannah C. Puhr⁵ reported the results of a survey that set out to clarify the treatments currently given to such patients. Out of 745 survey invitations, 113 oncologists from 89 institutions in 25 countries responded.

The results showed that, overall, clinicians tended to favour precision radiotherapy/radiosurgery (SRT/SRS) and systemic therapy when patients had fewer than ten brain metastases, and whole brain radiotherapy (WBRT) and systemic therapy where they had ten or more. But there was a high level of disagreement among experts, particularly in cases where patients had significant neurological symptoms. The researchers concluded that more trials were needed in order to determine the best treatment for these patients.

Understanding current practices in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is uncommon in Europe and most of the evidence concerning its management comes from countries where it is endemic, for example certain regions of East Asia. Dr Alvina Vadassery (medical fellow at EORTC) and Dr. Inês Leão are the first authors of an e-poster⁶ presenting the results from an international survey run by the EORTC Head and Neck Cancer Group (HNCG) distributed to members of four academic groups (EORTC HNCG, EHNS, DAHANCA and GORTEC) that set out to assess its diagnosis and treatment in non-endemic settings.

Responses from 131 institutions in 33 countries were analysed, and the researchers found considerable variations in practice. Most (78%) centres carried out routine testing for Epstein-Barr virus (EBV) in tumours, but only 47% tested for EBV DNA in plasma. Most centres used MRI or PET scans for staging, but differences were more pronounced in the choice of induction chemotherapy; 66% used gemcitabine plus cisplatin, and 24% docetaxel, cisplatin and 5-fluorouracil in EBV-positive NPC. Approximately one-third of centres treat patients with EBV-negative NPC differently. Advanced techniques were increasingly adopted across radiotherapy practices. The researchers conclude that clinical practice varies substantially across centres, challenging the use of real-world data as a robust external comparator and reinforcing the need for harmonised care and prospective studies.

⁵ https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal_2/presentation/list?q=Hannah+C.+Puhr#presentation-abstract-92191760620922
⁶ https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal_2/presentation/list?q=Alvina+Vadassery#presentation-abstract-19491698223578

Improving how progression-free survival is reported in cancer trials

Many trials of cancer treatments use progression-free survival (PFS) – the length of time patients live without their cancer worsening – as their primary measure of success or failure. But there is no general consensus on how to handle intercurrent events (IEs), for example a change in treatment during the course of the trial. Such events can change a study’s outcome and hinder the comparison of outcomes across multiple trials.

Dr Annemiek Van Ommen-Nijhof⁷ and colleagues carried out a review of 156 major cancer trials published in high-impact medical journals between 2020 and 2024, and which used PFS as their main endpoint. They focused on three commonly occurring IEs: disease progression after more than one missed assessment; treatment change prior to objectively assessed progressive disease; and treatment discontinuation in the absence of progressive disease. They then looked to see how these changes were handled and reported, and whether the researchers involved planned to carry out sensitivity analyses to test whether the IEs would affect the reliability of their results.

They found that, although sensitivity analyses were mentioned in 10-30% of the trials, the results were only reported in less than 5%. The researchers conclude that many new cancer therapies are adopted based on modest PFS gains, and that their findings underline the need for greater standardisation and transparency in the future.

Drug-drug interactions in PEACE III

The multi-centre EORTC PEACE III trial⁸ showed that adding the male hormone treatment enzalutamide to Radium 233 (Ra233), a type of internal radiotherapy, improved outcomes for patients with prostate cancer and bone metastases who were no longer responding to anti-testosterone treatment. However, it is known that enzalutamide may alter exposure to many coexistent medications, potentially affecting safety. Dr Mehdi Bsilat presented results from a follow-up analysis that investigated the relationship between enzalutamide and other medicines patients were taking, and any resulting side effects.

The researchers reviewed the records of 442 men who were taking other medications with enzalutamide. About 31% of the other medicines noted had a risk of a harmful interaction with enzalutamide, usually involving its lowering of the other medicine’s level. These interactions caused the patients taking enzalutamide to have more side effects; for example, heart problems, pain, high blood pressure, and nausea. Although the results show an association rather than a cause, clinicians should check for such drug interactions at the same of treatment with enzalutamide, the researchers say.

⁷ https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal_1/presentation/list?q=Van+Ommen#presentation-abstract-408092357710

⁸ https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal_1/presentation/list?q=Mehdi+Bsilat#presentation-abstract-52692119546499

What can patients teach us about informed consent?

EORTC has a long-standing history of involving patients in the review of patient information sheets and informed consent forms. But what can we learn from a decade of patient feedback to make informed consent materials more patient-friendly? A study presented by Iryna Shakhnenko⁸ sought to answer this question.

The researchers extracted patient reviewers’ comments from informed consent forms for 49 EORTC studies conducted in the past 10 years. They found that the dominant themes of comments were related to the clarity and understandability of information, study procedures and associated burdens, and the risk of participation. Additional patient priorities included transparent data and sample use, participants’ rights, patient-centred communication, trial sponsor accountability, and post-trial considerations.

The findings provide actionable guidance for improving patient facing consent documents in clinical trials, the researchers say. They support the need for clearer language, transparent communication on participant burden, risks, data use, and patient rights. Patient feedback also suggests that informed consent is not a one-time event, but an ongoing process requiring accessible information that supports patient understanding throughout their participation in the study. A follow up survey and focus groups are planned to validate and prioritise these themes, and thus enable the development of implementable standards that promote informed patient participation in clinical trials.

Capturing treatment-related toxicities through quality-of-life questionnaires

Emerging evidence suggests that clinicians may underreport symptomatic adverse events of head and neck cancer treatment compared to patients. In order to evaluate this, researchers investigated how two commonly-used patient questionnaires, the EORTC core quality of life questionnaire (QLQ-C30), and the head and neck cancer-specific module (QLQ H&N43), captured commonly clinician-reported systemic and radiotherapy-induced adverse events . It also sought to identify those adverse events that were not suitable for patient-reported outcome assessment.

The researchers reviewed European and US guidelines to identify 40 treatment head and neck cancer treatment regimes for analysis. The (very) common symptomatic adverse events were mapped to the symptom scales of the two questionnaires. Reporting their results, Dr Myrto Moutafi⁹ said that about 75% of the most common adverse events were symptomatic, and the remainder can only be captured through diagnostic testing. The most common adverse events related to systemic treatment were nausea and vomiting, diarrhoea, and loss of appetite. For radiotherapy, they were fatigue, mouth sores, and dry mouth. Of the 20 most frequently reported adverse events, 15 were symptomatic and were directly covered by one or both questionnaires.

The researchers conclude that, although the two EORTC questionnaires cover most of the symptoms patients experience during treatment for head and neck cancer, there is still a need for the evaluation of non-symptomatic adverse events to be undertaken by clinicians and through diagnostic testing.

⁸https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal/presentation/list?q=Shakhnenko#presentation-abstract-4505485331623
⁹https://cslide.ctimeetingtech.com/esmo2026/attendee/confcal_2/presentation/list?q=Myrto+Moutafi#presentation-abstract-64811232453602

The research presented by EORTC investigators at ESMO 2026 covered a broad range of topics, from clinical trial results and ongoing studies to research methodology, quality of life and patient engagement. Together, these presentations highlight the diversity of EORTC’s research activities and its continued commitment to generating evidence that informs cancer research and care.