People often treat the screening visit as a one-way process — the team evaluates you. But you're evaluating them too. Before you commit weeks or months of your time, and before you put your health in the hands of a particular study team, you have every right to understand exactly what you're getting into.
Most study coordinators are happy to answer questions. It's literally part of their job. These are the ones worth asking.
About the trial itself
Question 1
What phase is this trial?
Phase 1 means they're primarily testing safety in a small group. Phase 2 expands to test whether it works. Phase 3 compares it to standard treatment in a larger population. Each phase carries different risk and benefit profiles.
Question 2
How many people are enrolled in this trial — and how many sites?
A multi-site trial with hundreds of participants has more data behind it than a single-site study with 20 people. This affects how much the team knows about what to expect.
Question 3
What's the primary endpoint? What does the trial consider 'success'?
This tells you what they're actually measuring and optimizing for. Progression-free survival is different from overall survival. Quality of life outcomes are different from tumor shrinkage.
Question 4
What do you know so far about how the treatment is working?
If the trial has interim results, the team may be able to share them. They're not always allowed to, but it's worth asking.
About your participation
Question 5
Will I receive a placebo, and what are the odds?
In a randomized controlled trial, some participants get placebo. Ask the randomization ratio — 1:1 means 50/50; 2:1 means two-thirds receive active treatment. Know your odds before you agree.
Question 6
What is the visit schedule, and how long does each visit take?
Get the full schedule, not a summary. Some trials require visits twice a week for the first month. Know what you're committing to before you commit.
Question 7
Are there any medications I'll need to stop taking?
Some trials require washout periods — time off your current medications before you can enroll. This can affect your existing condition management. Discuss it with your regular doctor before agreeing.
Question 8
What are the most common side effects seen so far?
They'll tell you everything in the consent form, but asking them to summarize the most frequent ones gives you a clearer picture than reading a long list.
Question 9
If I experience a serious adverse event, what happens?
There should be a clear protocol. Who do you call? What are the emergency procedures? What happens to your participation in the trial?
Question 10
Can I continue my standard care while enrolled?
Some trials allow it; some replace standard care entirely. This is a critical question if you're currently on treatment that's working.
About costs and logistics
Question 11
What costs does the trial cover?
Study-related procedures are usually covered. Travel sometimes is. Your regular ongoing care usually isn't. Get a clear breakdown.
Question 12
Will I receive compensation, and if so, how much and when?
Most trials compensate for time and travel. The amount varies widely. Ask when payments are made — some reimburse at the end of each visit, others at the end of the study.
Question 13
What happens to my data after the trial ends?
Your anonymized data will almost certainly be used for research and regulatory submissions. Find out what identifiable information is retained and for how long.
About what comes after
Question 14
If I respond well to the treatment, can I continue accessing it after the trial ends?
This matters enormously if the treatment works for you. Ask whether there's an extension period, a compassionate use program, or a commercial path to access.
Question 15
What happens if I want to leave?
You can always leave. But ask what the process is — whether there's a formal exit visit, whether your data is retained, and what follow-up care you'll receive.
Medical Disclaimer: This guide is for informational purposes only. Decisions about clinical trial participation should be made in consultation with your healthcare provider.