According to a 2021 study1 across two UK tertiary centers, 22% of eligible patients declined to participate in Head and Neck Cancer (HNC) clinical trials. And among those who did enroll, many dropped out quietly, gradually — often due to predictable and preventable reasons.
In general, preventing dropout doesn’t start during follow-up… it starts during recruitment. And there are understandable reasons for that. HNC clinical trials, in particular, often involve complex treatments, multidisciplinary care, and a high burden for patients. That level of complexity doesn’t just make trials harder for patients to complete; it also makes them harder to join in the first place.
In this blog, we’ll focus on HNC as an example of why recruitment and dropout prevention are deeply connected, and how to improve them. The same barriers that keep some patients from enrolling can lead others to drop out later, which means solving one without the other simply doesn’t work.
The data from the UK study offers some patterns: older adults and patients from more deprived areas were significantly more likely to decline participation; others cited logistical burdens, unclear communication, or feeling overwhelmed by the demands of treatment. These are not isolated issues — they reflect broader structural barriers in how trials are designed and delivered. If we want to improve recruitment and reduce dropout, we need strategies that address these real-world challenges.
At IDDI, we’ve worked on nearly 900 oncology trials. The UK study aligned with what we’ve seen across some trials: patients often drop out — or never join — because the trial doesn’t fit their daily reality.
Strategies and Actions
These five practical strategies and actions we share here are based on our experience and the study’s findings — and while they’re especially relevant for head and neck cancer, they apply to many (if not all) complex trials:
1. Design studies patients can join, and can stay in
- If your protocol only works for patients with access to reliable transportation, strong caregiver support, and comfort with digital tools, you’re leaving out many others who could benefit — including those with limited resources, older adults, or people balancing complex daily responsibilities.
- Build flexibility into timelines and visits (this needs to be aligned with the endpoints of the trial).
- Make sure eligibility criteria reflect the diversity of real-world patients.
2. Build flexible participation pathways – Decentralized trials
- Reduce burden through decentralized or hybrid trials: telemedicine, remote PROs, wearable data, and home visits.
- When possible and feasible, partner with local clinics for follow-up assessments. This can reduce travel and make participation more sustainable.
3. Address common barriers from the start
- Offer transportation assistance, meal vouchers, and other forms of support to help cover additional costs.
- Provide flexible scheduling options to accommodate different needs.
- Use culturally sensitive materials and multilingual resources when relevant — especially in regions where participants may come from diverse cultural or linguistic backgrounds, such as in multinational trials across Europe or other global settings.
- For patients less comfortable with digital tools, offer phone-based follow-up instead of relying solely on apps.
4. Train your sites to build trust – Preventing dropout starts with relationships.
- Ensure site staff are trained to support the specific challenges patients with head and neck cancer may face, including communication difficulties, physical discomfort, and fatigue related to treatment.
- Keep personnel consistent across visits when possible. Continuity builds trust, and trust reduces dropout risk (or at least it should).
5. Track engagement like a real endpoint – Don’t wait for dropouts to happen.
- Monitor missed visits, declining PRO completion, and early disengagement.
- Set Key Performance Indicators (KPIs) for recruitment and dropout prevention (not just accrual).
- Use real-time data monitoring to flag issues early and act before patients disappear.
Recruitment and dropout prevention are two sides of the same challenge: building trials that work in the real world. At IDDI, we partner with sponsors to solve these and other challenges at every stage — from trial design to execution.
We help optimize eligibility criteria, define endpoints that are both clinically meaningful and relevant to patients, implement adaptive and decentralized strategies, and support data monitoring processes that help identify risks early. Whether you’re designing a new head and neck trial or trying to rescue one mid-study, our biostatistics, data management, and trial design teams are here to help make it work in the real world — not just on paper.
If you’re interested in exploring more, take a look at our Resources Page for more insights and case studies. And if you’re ready to talk about how your clinical trials can benefit from our support, feel free to reach out to me directly — or connect with one of our experts here.
We’d be happy to explore how we can help you move your trial forward!
Reference: [1] Rogers SN et al. Patient characteristics and refusal to participate in a head and neck cancer intervention trial. Annals of the Royal College of Surgeons of England. 2021; 104(2):121–124.
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