Clinical trials represent a great opportunity to take an in-depth look at what considerations a scientist has when setting up an experiment. Students can compare the kinds of controls needed, they can discuss who is blinded and why, or they can try to design a hypothetical experiment.
This topic is also great for an exploration of pseudoscience. There are many cancer ‘causes’ and ‘treatments’ that rely on no evidence, but are presented as scientific. Have your students go on a pseudoscience hunt and discuss what they find.