For a treatment to become part of standard treatment, it
must first go through 3 or 4 clinical trial phases. You do not
have to take part in all phases. The early phases make sure the
treatment is safe. Later phases show if it works better than
the standard treatment.
| Purpose | Number of people
who take part |
| Phase I |
To find a safe dose
To decide how the new treatment
should be given
To see how the new treatment
affects the human body | 15-30 people |
| Phase II |
To determine if the new treatment
has an effect on a certain cancer
To see how the new treatment
affects the human body | Less than 100 people |
| Phase III |
| To compare the new treatment
(or new use of a treatment) with
the current standard treatment | From 100 to
thousands of people |
| Phase IV |
| To further assess the long-term
safety and effectiveness of a
new treatment | Several hundred to
several thousand
people |
