Devita, Hellman, and Rosenberg's Cancer

LWBK1006-05 LWW-Govindan-Review November 24, 2011 11:20

Chapter 5•Epidemiology of Cancer 71

Question 5.8. In cohort studies, all of the following statements are true regarding relative

risk EXCEPT:

A. Relative risk is ratio of the disease incidence in the exposed group

and disease incidence in the unexposed group.

B. Relative risk is the difference between the disease incidence in the

exposed group and disease incidence in the unexposed group.

C. Relative risk measurement is useful in establishing causality for the

disease.

Question 5.9. Which of the following statements is true regarding the use of molecular

markers in epidemiologic studies?

A. Genotypic markers refer to protein sequences encoded by the genomic

DNA.

B. Genotypic markers do not generally change over time.

C. Single nucleotide polymorphisms (SNPs) are considered as pheno-

typic markers.

D. None of the above.

Question 5.10. Migrant studies have helped differentiate whether variations in cancer

rates across countries and among different racial and ethnic groups are

caused by environmental factors or inherited genetic factors. An example

of this is the difference in death rates from selected cancers comparing

Japanese in Japan with first- and second-generation Japanese in California

with native California whites. All of the following are true, EXCEPT:

A. Mortality from cancers of the stomach and liver is higher among

Japanese in Japan.

B. Among first-generation Japanese who migrated to California, the

mortality from stomach and liver cancer is substantially lower than

in Japanese in Japan and higher than in Californian whites.

C. The mortality from colon cancer approximately doubled among first-

generation Japanese who moved to California and approached the

rates of Californian whites by the second generation.

D. The mortality from colorectal cancer is higher among Japanese in

both the United States and Japan than in Californian whites.

E. All of the above are true.

Question 5.11. There has been increasing interest in the use of computed tomography

(CT) screening for lung cancer. Potential problems with CT screening for

lung cancer include:

A. Lead-time bias

B. Length-time bias

C. Neither

D. Both