Colon cancer incidences (excluding rectum cancer) among white American males, 1969 to 1971 Source: Third National Cancer Survey (1975)
| Age Group in Years | Median of the Age Group | Observed Incidence per 105 Population [(fa) × 105] | Calculated Incidence per 105 Population [(fa)cal × 105]a |
|---|---|---|---|
| 20–24 | 22 | 0.7 | 0.5 |
| 25–29 | 27 | 1.6 | 1.4 |
| 30–34 | 32 | 2.9 | 3.2 |
| 35–39 | 37 | 4.7 | 6.7 |
| 40–44 | 42 | 9.5 | 12.6 |
| 45–49 | 47 | 20.0 | 22.0 |
| 50–54 | 52 | 32.1 | 36.4 |
| 55–59 | 57 | 58.1 | 57.4 |
| 60–64 | 62 | 95.6 | 87.3 |
| 65–69 | 67 | 146.2 | 128.4 |
| 70–74 | 72 | 213.1 | 183.7 |
| 75–79 | 77 | 288.0 | 256.4 |
| 80–84 | 82 | 346.0 | 350.5 |
↵ a Based on the median-effect principle of the mass-action law, the regression line slope for log[[(fa)–1 – 1]–1 vs. log (age) is m = 4.982 ± 0.137; the y-intercept is yint = 11.988, and the correlation coefficient is r = 0.9958. The median-effect value is Dm = antilog (–yint/m) = 254.92 (years). The age-specific incidence rate is calculated by eq. 9; therefore, (fa)cal × 105 = [1 + (Dm/age)m]–1 × 105