Subject Selection in Clinical Trials
Author: Sarah Kenyon & Charlene Stone
Modifications: Rachel Hughes & Marti Lindsey
6 class periods
Time:
Preparation Materials for the experiment:
Time: sunscreens with different SPF levels
different brand sunscreens with the same
SPF levels
sunless tanning lotion
white and black material
plastic wrap and transparencies of different
colors
glass
polarizing and non-polarizing sunglasses
lip balms with and without SPF
UV light generating lamps (like tanning
beds)
outdoors access
fluorescent lamps
incandescent lamps
UV color changing frisbees (1 per group)
Make transparencies or photocopies of subjects
Digital camera
Materials: Subject descriptions
Designing Experiments
UV Exposure Lab Prep (Power Point Presentation
Does Sunlight Cause Skin Cancer? (pdf format)
Abstract
In this explain/apply lesson, students will be given the opportunity to design an experiment
looking at the ability of different substances to interfere with the transmission of UV rays from
different sources. They will then create a question appropriate for a Human Clinical trial based on
the results of their experiment. They will complete the lesson by creating a poster that includes a
description of their experiment and results, as well as a description of the proposed clinical trial.
They will be asked to make decisions as to who should be included and who should be excluded
based on inclusion and exclusion criteria that they will construct for a provided subject list.
Students will also predict results and describe the implications of these predictions.
Objectives
Students will:
1) Design and conduct an experiment to test a hypothesis
2) Create a question/objective based on the results of their experiment that can be
answered by performing a human clinical trial.
3) Write inclusion and exclusion criteria and apply these criteria to a pool of subjects
4) Predict results of the study and describe implications of the predicted results
National Science Standards:
Content Standard A: Scientific Inquiry
Identify questions that guide scientific inquiry
Content Standard E: Science and Technology
Communicate the problem, process, and solution
Content Standard F: Science in Personal and Social Perspectives
Personal and community health
Natural and human-induced hazards
Science and Technology in local, national and global challenges
Teacher Background
As with the previous lesson, it is important to have a good understanding of the nature of clinical
trials. The following website can provide this information:
http://www.webmd.com/content/pages/13/65814.htm?z=1104_08950_8900_ct_01. Additional
information can be found at the Clinical Trials information page.
Does Sunlight Cause Skin Cancer? http://www.ccohs.ca/oshanswers/diseases/skin_cancer.html
Related and Resource Websites
http://www.webmd.com/content/pages/13/65814.htm?z=1104_08950_8900_ct_01
http://www.clinicaltrials.gov/
Designing Experiments and Writing Lab Reports http://www.ncsu.edu/labwrite/
Activity
1. At the beginning of class remind students of the article, “Does sunlight cause skin
cancer?” which they read during one of the stations of the explore lesson, Sun, Skin
and Cancer.
2. Elicit from the students the main points covered in the article. Encourage them to
point out that there are different types of light, the exposure to which can cause
different ill effects to skin. Students should also point out that these negative effects
can be prevented in a number of ways- by reducing the amount and type of UV that
the skin is exposed to- through materials, sunscreens, and other products.
3. Explain to the students that they should draw upon that reading to develop an
investigation where they test the effectiveness of certain products to reduce the
effects of UV rays. Tell them, “First you will design non-human experimental trials to
test a question of your choosing, and then design a human clinical trial. At the front
of the room there are a number of materials with which you can design your
experiment; the only requirement is that you must be testing these materials in
response to UV light.” There should be sunscreens of different SPF levels and
different sunscreens with the same SPF level as well as sunless tanning lotions,
white and black material, plastic wrap and glass, polarizing and non-polarizing
sunglasses, plus lip balms with and without SPF. There will be UV-light generating
lamps, as well as access to the outdoors and fluorescent and incandescent lamps.
UV reactive Frisbees will be used as indicators of UV blocking.
4. Students will (in groups) use the Designing an Experiment and Writing a Hypothesis
handout to record their question, their prediction and hypothesis as well as a method
or protocol for their experiment
5. On the second day, students will conduct their experiment. When they have
completed the experiment they will write their results. It would be useful to have a
digital camera on hand to take pictures, as the results are likely to be qualitatively
visual.
6. As they finish, have students clean up their areas and brainstorm, as a group, on any
questions that their experiment raised that could be answered with human trials.
Have them, as a group, identify one of these research questions that they might like
to address and what the objective of this study will be. (i.e. “We want to address
whether brand name sunscreen A (SPF 15) works as well as generic sunscreen B
(SPF 15) at blocking the effects of UV rays from the sun on human skin, with the
objective to see effectiveness versus price”).
Subject selection (day 3):
7. Ask the class “What are some reasons why some people should be excluded from a
study? Are there certain people who are riskier to have in a study than others?
Why? How homogeneous should your study group be? Does this depend on your
question? How does the homogeneity of your study group affect the study size?
What reasons are there to limit the number of subjects in your study? What reasons
are there to increase the number of subjects?”
8. When the class has considered these questions, have them individually come up with
a list of exclusion and inclusion criteria for their particular study.
9. Then have each research group get together and pool their ideas and write a
common inclusion and a common exclusion criteria for their study.
10. Each group will then receive a handout with a list of potential subjects, and they will
choose appropriate subjects for their study (indicated by a check next to the included
subjects) and a reason why each excluded patient was excluded, based on their
exclusion criteria.
11. Each group will then identify (if desired) additional criteria for exclusion that they may
have identified by assessing the provided subjects.
12. Then tell students that for their clinical trial, they MUST have 14 subjects from this
list. If they have more, who do they now exclude? If they have fewer, who do they
now include?
13. Ask the class to generate a list of exclusion criteria (you will only do this for now
(??))- taking note on the board of when there are ones common to multiple groups.
14. Then ask the class: “Which groups had not excluded enough subjects? What did you
use as extra criteria for exclusion? Which groups had excluded too many? What
criteria did you use to include some subjects you had already excluded? What might
these decisions mean for your results? Do you feel what you did was appropriate? If
not, what would you, if you were a researcher in this position, do differently?”
Treatment selection (day 4):
15. Now that students have their included subjects, they will be asked to divide them into
their treatment groups. Each research group should identify the treatment groups
they have and how they are assigning subjects to each treatment. They should
identify, in writing, how the way they assigned treatments will achieve their stated
research objective. (random vs. matched)
Poster creation (days 4-6):
16. Student research groups will then be responsible for creating a “Human Clinical Trial”
addition to their poster. These posters must include:
a. Results from their pre-clinical experiment
b. Clinical proposal (research question, objective, rationale and treatments)
c. Inclusion criteria
d. Exclusion criteria
e. Predictions
17. Posters should be ~60% from a, with the remaining 40% from b-e.
Museum Walk (day 6):
18. Students will place posters around the room and take turns standing by their poster
as the other students in the group rotate through the other posters.
Closure
Have students respond to the following in their science notebook: “In what way do our lessons on
the physiology of skin, our survey of recent research of skin cancer issues and our creation of a
clinical trial address Environmental Health?” Have them also write their own definition of
“Environmental Health”. Discuss their answers as a class.
Embedded Assessment
Through their group topics, teachers can assess their ability to work together to generate
questions based on their current knowledge. Their ability to visually represent their experiment
and Clinical trial proposal, presentation skills, as well as the ability to listen and respond or
appropriately question new material can be assessed during the Museum walk. In their final
responses to the provided statement or question, they will be assessed as to their ability to
integrate the information in the lessons in this learning cycle and describe it in relationship to the
larger concept of Environmental Health.
Homework
Throughout the week, students will work on their questions, methods, and poster presentation
both in class and at home.