Question

A tamoxifen study claims that a combination of chemotherapy and the hormone therapy tamoxifen is more effective than tamoxifen alone in preventing breast cancer. In the study, a group of researchers from the U.S. and Canada studied 1477 postmenopausal women with early-stage breast cancer. The women were randomly assigned to one of three study groups. The first group of 361 received tamoxifen alone on a daily basis for five years. The second group of 566 received chemotherapy and tamoxifen for six months, and then completed five years of tamoxifen treatment. And the third group of 550 received chemotherapy alone for six months followed by five years of tamoxifen treatment. All 1477 patients knew which treatment they were receiving.

In this study, which is the control group?

a the second group of 566 that received tamoxifen and chemotherapy concurrently for 6 months

b the first group of 361 that received tamoxifen alone

c the 1477 postmenopausal women

d the third group of 550 that received chemotherapy alone for 6 months and then tamoxifen for 5 years

• There is no control group.

This study is

a double-blind

b not blind.

c blind, but not double-blind

d not an experiment

e none of the above

Answer 1

1) The control group is

Option b : the first group of 361 that received tamoxifen alone

  Explanation : A control group is the group in a study that does not use the thing being tested and is used as a benchmark to measure the results of the other group. In this scenario, control group is the group that does not receive the treatment, but are only there for comparison purposes.The first group is not subjected to the treatment of chemotherapy and  hormone therapy tamoxifen. They receive tamoxifen alone and is used as a benchmark in the study to determine whether the alternative treatment of chemotherapy and tamoxifen is better.

2) The study is

Option b: not blind

Explanation : A blind study is one where neither the members of the treatment group nor members of the control group know to which of the 2 groups they belong . A double blind study is one where neither the subjects nor the scientists conducting the experiments know which subjects are in control group and in treatment group.

In this scenario, researchers know what treatment is given to each subject. Hence it is not blind