How can data be used in retrospective studies?

How can real world evidence lead to FDA label changes?
How can real world data be used to guide treatment decision making?
When should bone marrow biopsies be repeated?
What is the post-bone marrow biopsy procedure care protocol?
What happens during the bone marrow biopsy procedure?
How are the findings of a bone marrow biopsy used?
What is the role of sedation for bone marrow biopsies?