Question

CRC is the second most common cancer diagnoses in industrialized nations. Risk of developing colon cancer increases with age. A family history of colon cancer is another major risk factor. Individuals with one first-degree relative diagnosed after age 50 have a relative risk of 1.6. That increase to 2.6 if the relative was diagnosed before age 50. The presence of two first degree relatives diagnosed with colon cancer increase the risk further. Relative Risk is 3.5 if both realties were diagnosed after age 50; RR = 5.6 if either or both were diagnosed before age 50.

You are a primary care provider and one of your patients, Mr. Jones, is a 50-year-old male with no history of colon cancer. He has heard about the recommendations for colon cancer screening and has some questions for you. How commonly is colon cancer diagnosed in the U.S.? Is Mr. Jones at increased risk? The CDC reports that 136,717 cases of colon cancer are diagnosed annually. Of those 136,717 cases of CRC, 70,223 were male and 66,494 were female. Of the US population, 148,640,424 are male and 152,711,352 are female.

Mr. Jones is curious as to whether his gender places him at increased risk. Of those 136,717 cases of CRC, 70,223 were male and 66,494 were female. Mr. Jones is also curious about whether his old age places him at increased risk for CRC.

Exhibit 1:

Age	Cases	Population	Rate/100,000
<1	0	2,141,127
1-4	0	8,559,824
5-9	0	10,353,968
10-14	0	10,039,911
15-19	26	10,844,290
20-24	97	10,881,353
25-29	223	10,922,914
30-34	510	9,936,086
35-39	900	10,173,758
40-44	1851	10,307,818
45-49	3678	11,072,321
50-54	6673	10,462,503
55-59	7534	9,017,505
60-64	8740	7,430,412
65-69	9487	5,406,398
70-74	8986	4,002,885
75-79	8362	3,087,390
80-84	7023	2,252,255
85+	6129	1,747,706
<50	7285	105,233,370
50+	62934	43,407,054

1. Assume a total US population of 301,351,776; Calculate the overall incidence rate per 100,000 of colon cancer in the U.S.

2. Calculate the incidence rate for males and females and the relative risk (males vs. females)

3. Calculate the incidence rate for each age category and for males older and younger than 50 (i.e. complete the table Exhibit 1).

4. Calculate and interpret the relative risk for males aged 50 and over as compared to males younger than 50.

5. Assume that there are 538,584 males 50 and older alive with CRC, and 31,346 males younger than 50 alive with CRC. What are the prevalence rates (per 100,000) for each group?

Answer 1

1.45 cases of colon camcer per 100000.. ( 136717/total us population * 100000)

2.47 CRC/ 100000 for males

44 CRC/100000 for females

Relative risk for males vs females 47/44= 1.07

4.relative risk >50/<50=21

5.prevalence rates 50+ =1240.77

Prevalence rates<50 = 29.78

3.

Exhibit 1:

Age	Cases	Population	Rate/100,000
<1	0	2,141,127	0
1-4	0	8,559,824	0
5-9	0	10,353,968	0
10-14	0	10,039,911	0
15-19	26	10,844,290	.023.
20-24	97	10,881,353	.891
25-29	223	10,922,914	2.04
30-34	510	9,936,086	5.13
35-39	900	10,173,758	8.84
40-44	1851	10,307,818	17.95
45-49	3678	11,072,321	33.21
50-54	6673	10,462,503	63.78
55-59	7534	9,017,505	83.5
60-64	8740	7,430,412	117.6
65-69	9487	5,406,398	175.4
70-74	8986	4,002,885	224.4
75-79	8362	3,087,390	270.8
80-84	7023	2,252,255	311.8
85+	6129	1,747,706	351.6
<50	7285	105,233,370	6.9
50+	62934	43,407,054	144.9