Epi in the News

Thank you Sujit for this very interesting method of teaching_learning. 

My answer is as follows: 

1. What was the study design?

Phase 3 clinical trial of combination immunotherapy versus standard chemotherapy among advanced head and neck cancer. 

No information is given about randomisation.

Its a superiority trial.

1b. Why can't you investigate this hypothesis with a cross-sectional design?

The outcome of the trial is a time to event outcome and hence cannot be measured with a cross-sectional design.

2. What were the exposure categories?

Combination immunotherapy (nivolumab and ipilimumab) vs standard chemotherapy

2b. Why did the researchers not use a placebo control?

Using placebo would be unethical. Participants should be provided the standard of care ( which is standard chemotherapy in this case). 

3. What was the outcome of interest?

a. Primary: Survival rate

b. Secondary: adverse effects of treatment

4. Was the outcome measured as a prevalence, incidence risk, or incidence rate? Why was this a sensible choice?

The outcome was measured as an incidence rate as it is a time to event measure. 

5. There's evidence of effect modification implied in the article. Can you find it? (Most of you wont be able to answer this yet)

The effect of immunotherapy combination varies with the presence or absence of PD-L1 marker. Hence there is evidence of effect modification by PD-L1. 

6. What are some of the mediating factors for this exposure-disease relationship? (This question is beyond the scope of our modules, but I'll ask anyways)

?? smoking status, PD-L1 mrker

Soujanya Kaup

1. What was the study design?

Ø  Intervention study design(phase 3 clinical trial)

1b. Why can't you investigate this hypothesis with a cross-sectional design?

Ø  Its because you have to assign the intervention in one group(nivolumab and ipilimumab) and compare the assigned intervention with the control group and in this case the group which is receiving the normal cancer treatment(chemotherapy and surgery)

2. What were the exposure categories?

Ø  The exposure category were people receiving new treatment of cocktail of immunotherapy medications harnessed patients’ immune systems to kill their own cancer cells(nivolumab and ipilimumab).

2b. Why did the researchers not use a placebo control?

Ø  The researcher did not use the placebo because it was unethical and would lead to loss. In this case placebo were people receiving the normal cancer treatment

3. What was the outcome of interest?

Ø  The outcome of interested was suppressed tumor and  increased survival time

4. Was the outcome measured as a prevalence, incidence risk, or incidence rate? Why was this a sensible choice?

Ø  The outcome was not measures in prevalence, incident or incident rate as this was not sensible. The disease in question is rare and the suppression of tumor and increased survival time was measures

Ø  May be survival rate

5. There's evidence of effect modification implied in the article. Can you find it? (Most of you wont be able to answer this yet)

Ø  PD-L1

6. What are some of the mediating factors for this exposure-disease relationship? (This question is beyond the scope of our modules, but I'll ask anyways

Ø  Patient immunity

Ø  Genetic factors related to cytokine production

1. Interventional trial ( phase 3) not sure of if there is randomization however and nature of comparison group if any 

1b.  the temporal relation won't be accurately estimated  ( causation won't be established, only association ) 

2. immunotherapy ( combination of nivolumab and ipilimumab ) 

2b. that will be unethical in presence of " standard of care" 

3. reduction in tumor size and survival rate 

4.  incidence rate . Sensible because of the high variability of follow up time  

5. they talked about ( reduction in size ) and others for whom the tumor completely disappeared and that there is relation with certain biomarker PD-L1"

6. not sure but will it be the presence of PD-L1??!

thank you for posting this exercise 

1. What was the study design?

Interventional study non-randomized

1b. Why can't you investigate this hypothesis with a cross-sectional design?

A cross-sectional design studies a population in a specific point of time regarding an outcome and/or exposure, and does not study its evolution over time. It does not involve interventions either.  

2. What were the exposure categories?

Exposure: Cocktail of immunotherapy medications (nivolumab and ipilimumab)

Not exposed: Standard care (chemotherapy)

2b. Why did the researchers not use a placebo control?

Because it would not be ethical to deprive patients of treatment when there is an approved chemotherapy regimen. 

3. What was the outcome of interest?

- Primary: Survival rate 

- Other: Reduction in tumor size , side effects

4. Was the outcome measured as a prevalence, incidence risk, or incidence rate? Why was this a sensible choice?

Incidence rate. It was sensible because patients did not start taking the medication at the same time and the follow-up time was variable. 

5. There's evidence of effect modification implied in the article. Can you find it? (Most of you wont be able to answer this yet)

Tumors with high levels of the immune marker PD-L1 had higher survival rates.

6. What are some of the mediating factors for this exposure-disease relationship? (This question is beyond the scope of our modules, but I'll ask anyways)