1.1. Increasing age and lifestyle factors are both associated with an increased risk of having cancer.

Smoking has been identified as a risk factor for a number of cancers.

Suggest how smoking can cause cancer.

1.2. The leading cause of cancer-related death in the United States (USA) is cancer of the lungs and bronchi.

Table 1 below shows the number of new cases and deaths related to cancer of the lungs and bronchi in the USA between 1993 and 2018.

Table 1

Showing your working, calculate the average rate of decrease per year in the number of new cases of lung and bronchus cancer between 1993 and 2018.

Express your answer to two significant figures.

1.3. The data in Table 1 suggests that the incidence of lung and bronchus cancer in the USA is decreasing.

Suggest why this could be.

1.4. Compare the data between the number of cases versus the number of deaths in Table 1.

Describe the trend seen in the data and suggest possible reasons for the pattern observed.