In year of 1999, 4,458 women were screened for cervical cancer and 72 were found to have CIN 3 stage or above (diagnostic of carcinoma of the cervix or carcinoma-in-situ). The women who did not have cervical cancer were re-screened in 2004 and another 40 cases were diagnosed.

a) Explain the prevalence of the cervical cancer in 1999 and 2004?

b) Specify how many women were at the risk of developing the cervical cancer before being screened in

i) 1999, and

ii) 2004.

c) Describe the incidence of cervical cancer within these women? Is this a measure of cumulative incidence or incidence rate?

Assume that, on average, each of 30 women who were diagnosed along with cervical carcinoma did so half-way through during the five-year period.

d) Find the total number of person-years at the risk of developing cervical cancer at the time of five years.

e) State the incidence rate of cervical cancer in these women?