Patients in both the cancer and non-cancer samples who were older or had greater comorbidity were less likely to survive 5 years (Table ). Age alone was an insufficient predictor of both overall survival and CRC-specific case fatality rate. For instance, among men who were 75–79-years-old with zero conditions, the 5-year survival for patients with CRC was 49.3%, compared to 82.9% for those without cancer, yielding a CRC-specific case fatality rate of 33.6% (Table , Col. D). Among men in the same age group who had ≥3 conditions, the CRC-specific case fatality rate was only 16.4%, due to a smaller difference in survival between the cancer (27.3%) and non-cancer (43.7%) patients. Similarly, the CRC-specific case fatality rate for patients diagnosed at age 75–79 years was 32.9% for women with zero conditions, compared to 21.3% for women with ≥3 conditions (Table , Col. D). As a result, the annual CRC mortality rate (incidence x CRC-specific case fatality) was lower for patients with a greater comorbidity burden (Table , Col. D-F).
Colorectal Cancer-Attributable Mortality Rates for Men
Women tended to have lower CRC incidence, but a slightly higher life expectancy. For men without cancer, life expectancy ranged from a high of 15.1 years in the youngest, healthiest cohort to a low of 3.5 years in the oldest, least healthy cohort (Table ). For women without cancer, life expectancy ranged from a high of 17.5 years to a low of 3.8 years (Table ). The life expectancy of both men and women aged 75–79 years with zero conditions (10.3 and 11.9 years) exceeded that of patients age 67–69 years with ≥3 conditions (7.4 and 8.8 years, respectively).
Benefits and Harms of Screening Colonoscopy for Men
Benefits and Harms of Screening Colonoscopy for Women
Among the non-cancer patients who received SC, the 30-day mortality rate was 0.10%. Among those who survived 90 days past SC, the 30-day mortality rate was 0.07%, resulting in a colonoscopy-attributable mortality rate of 0.03% or 30 deaths per 100,000 persons screened. The stratum-specific mortality rates ranged from 15.4 deaths per 100,000 for patients 67–74 with zero conditions to 92.2 deaths per 100,000 for patients aged 80–94 with ≥3 conditions.
The magnitude of benefit of SC (reduction in CRC mortality) was lower among patients with more comorbid conditions. For example, among men aged 75–79 years with no comorbidity, the number of life-years saved was 459 per 100,000 SC. In contrast, men who were younger (67–70 years old) but had ≥3 comorbidities had a benefit of only 81 life-years saved per 100,000 SC (Table , Col. G). The number of life-years saved for women 75–79-years-old with no comorbidity versus 67–70 years old with ≥3 comorbidities was 509 and 130 per 100,000 SC, respectively (Table , Col. G).
For most strata, pay-off time was in the range of 5–7 years. Among those who were expected to outlive pay-off time, there was substantial variation in the magnitude of SC benefit. For example, women aged 70–74 years with ≥3 comorbidities were expected to outlive their pay-off time by only 1.7 years, while women of the same age with zero comorbidities were expected to outlive pay-off time by nearly 10 years. The number of life-years saved (Table , Col. G) reflected the variation in the time expected to live past pay-off time (Table , Col. F) as well as variation in SC benefit (Table , Col. B). Among men who were expected to receive some benefit from SC, the number of life-years saved ranged from 12 to 1,128 years per 100,000 patients screened (Table ). For women, the range was from 34 to 989 years per 100,000 patients screened (Table ). The life-years saved were very similar for both sexes among the lower comorbidity strata for all age groups (Fig. ).
Number of life-years saved by sex, age, and comorbidity strata.
The number of life-years saved was greater than 100 per 100,000 patients screened for men and women aged 67–84 years with zero comorbidities and aged 67–79 years with 1–2 comorbidities, and for women aged 67–69 with ≥3 comorbidities or 85–94 with zero comorbidities. No life-years were saved, indicating no benefit from SC, for all patients ≥75 with ≥3 comorbidities or 85–94 with 1–2 comorbidities (Fig. ).
Screening colonoscopy decision rule.
In our sensitivity analysis, in which we reduced the CRC mortality rate by 50% to account for prior negative SC, the categories remained the same for 23 of the 30 strata (Appendix 2
). However, there were three strata (males and females ages 80–84 with 1–2 comorbidities, males ages 70–74 with ≥3 comorbidities) for which there was an expected benefit of SC in the main analysis but no benefit in the sensitivity analysis. Additionally, the number of life years saved was substantially lower in many of categories.