Highlights
The ELAN-RT trial established that hypofractionated split-course radiotherapy (HSC-RT) is non-inferior to standard fractionated radiotherapy (SF-RT) regarding locoregional response at six months in frail patients aged 70 and older.
HSC-RT significantly reduced the treatment burden, requiring only 20 fractions compared to the 35 fractions necessitated by the standard protocol.
While HSC-RT showed a more favorable acute toxicity profile, a concerning trend toward decreased median overall survival (13.0 vs. 18.9 months) suggests that patient selection remains the most critical factor in clinical decision-making.
Background: The Challenge of Managing Frailty in Head and Neck Oncology
Head and neck squamous-cell carcinoma (HNSCC) is increasingly a disease of the elderly. As the global population ages, clinicians are more frequently encountering patients aged 70 and older who present with localized but unresectable disease. Historically, the gold standard for these patients has been standard fractionated radiotherapy (SF-RT), typically delivering 70 Gy over seven weeks. However, this intensive regimen is often poorly tolerated by older adults, particularly those living with frailty, multiple comorbidities, or diminished functional reserve.
The toxicity of SF-RT—ranging from severe mucositis and dysphagia to profound fatigue and dehydration—frequently leads to treatment interruptions, hospitalizations, and a permanent decline in quality of life. Consequently, many radiation oncologists have traditionally utilized tailored, hypofractionated, or split-course regimens in an attempt to balance oncologic control with patient safety. Until the publication of the ELAN-RT trial, these alternative approaches lacked high-level evidence from randomized controlled trials, leaving a significant gap in evidence-based guidelines for the geriatric population.
The ELAN-RT Trial: Designing a Study for the Vulnerable
The ELAN-RT trial was a multicenter, open-label, randomized controlled trial conducted across 30 centers in France and Monaco. It specifically targeted a population often excluded from major clinical trials: frail older patients. The study investigators defined frailty based on a comprehensive geriatric evaluation, ensuring the results would be directly applicable to the most vulnerable subset of patients.
Patient Population and Methodology
Between 2013 and 2018, the trial enrolled 202 patients aged 70 years or older (median age 82) with stage II-IV HNSCC. All patients were assessed as frail and were treated with curative intent. Participants were randomized 1:1 to receive either the standard SF-RT (70 Gy in 35 fractions over 7 weeks) or the experimental HSC-RT (55 Gy in 20 fractions, delivered in two courses of two weeks each, separated by a two-week rest period).
Study Endpoints
The primary endpoint was the proportion of patients alive with a complete locoregional response at six months post-treatment. This endpoint was chosen to reflect both the efficacy of the radiation in controlling the tumor and the patient’s ability to survive the immediate post-treatment period. The non-inferiority margin was set at 16%.
Key Findings: Non-Inferiority and Clinical Efficacy
The results of the ELAN-RT trial provide a nuanced view of how radiotherapy can be adapted for the elderly. In the intention-to-treat population, 35% of the HSC-RT group were alive with a complete locoregional response at six months, compared to 33% in the SF-RT group. The difference of +2% (95% CI -11 to 15) successfully met the criteria for non-inferiority, confirming that the shortened, split-course regimen does not sacrifice early local control.
The Survival Disparity
Despite meeting the primary endpoint for locoregional control, the secondary endpoint of overall survival (OS) revealed a more complex picture. The median OS was 13.0 months in the HSC-RT group versus 18.9 months in the SF-RT group. While the hazard ratio (1.32, 95% CI 0.97 to 1.81) did not reach statistical significance, the five-month difference in median survival is clinically substantial. This suggests that while the tumor may respond similarly at the six-month mark, the long-term curative potential or the systemic impact of the higher total dose in the standard arm may provide a survival advantage for those who can endure it.
Safety and Tolerability Profiles
One of the primary arguments for hypofractionated and split-course regimens is the reduction in acute toxicity. The ELAN-RT trial supported this hypothesis. Acute adverse events of grade 3 or higher occurred in 36% of the HSC-RT group compared to 47% in the SF-RT group. Although the p-value (0.13) did not indicate a statistically significant difference in the trial’s specific sample size, the absolute reduction of 11% is meaningful for a frail patient population where a single severe adverse event can lead to a loss of independence.
Interestingly, the number of deaths within 30 days of completing radiotherapy was slightly higher in the HSC-RT group (5%) than in the SF-RT group (3%), highlighting the inherent risks of treating this demographic regardless of the protocol used. The split-course design, however, offers a logical ‘safety valve’—the two-week break allows for recovery of the oral mucosa and nutritional status, potentially preventing the cumulative toxicity that often halts standard treatment in the fifth or sixth week.
Expert Commentary: Navigating the Trade-off
The ELAN-RT trial is a landmark study because it validates a practice that many clinicians were already performing but without the backing of a randomized trial. However, the interpretation of the results requires caution. The trend toward shorter survival in the HSC-RT arm is a significant red flag. It implies that for patients who are ‘borderline’ frail—those who might have the reserve to complete a full seven-week course—standard fractionation remains the superior choice for maximizing life expectancy.
The biological rationale for the split-course regimen involves allowing normal tissues to repair during the break. However, the risk is that the tumor cells also repopulate during this interval. The lower total dose (55 Gy vs. 70 Gy) in the HSC-RT arm likely contributes to the lower toxicity but may also be the reason for the observed survival gap. Therefore, HSC-RT should not be viewed as a replacement for standard care but as a valuable alternative for patients whose geriatric assessment suggests they would likely fail to complete a 35-fraction course.
Conclusion: A Personalized Approach to Geriatric Radiotherapy
The ELAN-RT trial successfully demonstrated that hypofractionated split-course radiotherapy is a viable, non-inferior option for achieving short-term locoregional control in frail older patients with HNSCC. It offers a more manageable schedule and a trend toward lower toxicity, which are paramount considerations in geriatric care.
However, the survival data reinforces the necessity of a multidisciplinary approach. Every patient aged 70 or older with HNSCC should undergo a formal geriatric assessment before a treatment plan is finalized. If a patient is deemed too frail for the rigors of a seven-week course, the HSC-RT protocol provides an evidence-based pathway that respects the patient’s vulnerability without abandoning curative intent. For those who are fit or only mildly frail, the standard 70 Gy regimen remains the goal for optimizing survival.
Funding and Clinical Trial Information
This study was sponsored by the Groupe d’Oncologie Radiothérapie Tête et Cou (GORTEC) and funded by the French programme PAIR-VADS 2011, GEMLUC, and GEFLUC. The trial is registered with ClinicalTrials.gov, number NCT01864850.
References
Ortholan C, Aupérin A, Tao Y, et al. Hypofractionated split-course versus standard radiotherapy in frail older patients with head and neck squamous-cell carcinoma (ELAN-RT trial): a non-inferiority, multicentre, open-label, randomised controlled trial. Lancet Healthy Longev. 2026;7(1):100812. doi:10.1016/j.lanhl.2025.100812.
Extermann M, Overcash J, Diehl ME, et al. Predicting cancer-specific and other-cause mortality in older patients with cancer: the G8 and beyond. J Clin Oncol. 2014;32(24):2580-2586.