A protocol is the clinical trial’s ‘operating manual’.
This detailed document ensures all investigators follow the same process in recruiting and treating patients. Consistency allows data to be pooled in multicentre trials.
Parents have the right to see and keep a complete copy of the protocol document for their child’s study.
In addition to treatment information, the document also includes:
- Study hypothesis
- Experimental design and background
- Eligibility criteria
- Number of participants
- Study duration
- Randomization structure
- Therapy description
The question being asked by the investigators
Experimental Design And Background
A thorough analysis of the research preceding this study is provided, along with relevant references from the scientific literature. The rationale for this study is explained, and success criteria are defined.
Protocols must include details of who can and cannot participate in the clinical trial. Criteria include age, location and stage of disease, prior treatment and other medical conditions. Strictly following these rules is vital to ensure reliable data that enable investigators to answer their questions / hypotheses.
Number of Participants
Sponsors must decide the number of patients they wish to recruit. Numbers impact the study’s ability to reliably identify a difference between standard and experimental treatments. This is called the trial “power”. Statistical power increases with more patients.
The goal is usually to obtain a statistically significant result that helps answer the study hypothesis. The number of patients required depends on the question posed. For example, showing effectiveness of a treatment for trilateral retinoblastoma (usually fatal) requires fewer patients than testing treatment for small intraocular tumours (highly curable).
Cancer clinical trials often last for many years. Thoroughly assessing whether treatment has been effective, and what the side effects are requires many patients and long-term follow up.
When the cancer is rare, a large number of patients must be enrolled to detect a meaningful effect (statistical power). Finding patients with the same degree of disease and prior treatment criteria, and obtaining their consent, can be very difficult. Shortage of eligible participants is the greatest barrier to completing a clinical trial for treatment of a rare cancer like retinoblastoma.
If the trial is randomized, this section describes the different arms and the randomization process. The control group is also identified, if there is one.
Required tests, treatments and supportive care are described in full. Each arm is described if the trial is randomized.
The following is also detailed:
- pathology assessment criteria
- each drug, its potential interactions and side effects
- toxicity definitions and management
- clinical features of the success criteria
- relapse therapy
Treatment may be altered according to the toxicity details. For example, if your child has low blood counts or a drug reaction.
Sponsors, lead investigators, collaborators and contact details are included. The process for record keeping and reporting of adverse events is also described. The consent form is the last part of this section.
Protocols vary in length and may be over 100 pages. An abbreviated quick reference version of several pages is often given to parents, but you have the right to be given the complete version. Just ask for a copy.