L20 - How Do You Know a Treatment Works?

Question 1

How are tumour responses classified?

Answer 1

1 - Complete response - disappearance of all signs of disease

2 - Partial response - a reduction in tumour volume by at least 30%

3 - Stable disease - no significant change

4 - Disease progression - an increase in tumour volume by at least 20%, or the presence of new metastases

*A positive tumour response doesn’t necessarily mean prolonged survival

Question 2

In which ways can survival time be measured?

Answer 2

• Overall survival time is the time from the start of the treatment to death
• Disease-free survival time is the time between a radical treatment removing a disease and the point at which the disease relapses (if ever)
• Progression-free survival time is the time prior to disease progression

Question 3

What is a hazard ratio?

Answer 3

• A hazard ratio is a measure of relative difference in survival time between a new and a standard treatment
• Hazard ratio = risk of death in the new treatment / risk of death in the standard treatment

Question 4

List the phases of clinical trials.

What are the aims of these phases?

Answer 4

• Phase 1: to find a safe dose of a new treatment and understand the toxicities
• Phase 2: to determine if the new treatment has sufficient efficacy to be worthy of further investigation
• Phase 3: to provide sufficient evidence to potentially change clinical practice (RCT)