Colorectal Cancer Mortality Projections

Key Findings >

Question: How can we accelerate the reduction in colorectal cancer mortality most effectively?

Answer: Our simulation models predict that if we maintain the current rate of improvement in reducing risk factors, increasing screening, and using chemotherapy, we will see a continued reduction in colorectal cancer mortality. Beyond that, an even higher usage of screening has the largest additional impact on mortality over the next 15 years. However, the impact of delivering the best available chemotherapy to anyone who could benefit from high quality care could be immediate, responsible for almost all the further reduction in mortality for the first 5 years.


Detailed Discussion

The following graph illustrates the additional decline in mortality that our simulation models predict, given optimistic assumptions about risk factor, screening and chemotherapy improvements, over our Projected Trend baseline. The baseline projection assumes that trends in risk factors, screening and treatment will continue at their 1970-2004 rate—a challenge in some areas. (See the section on Projection Scenarios for a detailed discussion of assumptions.)

The bar chart below shows how much impact each intervention scenario has on CRC mortality and when. The impact is measured by the percent change in CRC mortality from the projected trend baseline for that year. The red bars show the effect of meeting Optimistic but Realistic goals for risk factors while screening and chemotherapy are held at projected trend levels. The blue and green bars show the effect of meeting Optimistic but Realistic goals for screening and chemotherapy, respectively, while other interventions remain at projected trend levels.

Graphs showing the Both Races, Both Sexes results for the combined (average) model. The scenarios displayed are the the projected trends baseline, Risk Factors (Optimistic Goals), Screening (Optimistic Goals) and Chemotherapy (Optimistic Goals)

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We can see that the most effective short-term intervention is to improve access to quality treatment (green bars). Our models assume that there are two ways to achieve better treatment: assure that everyone treated for CRC gets the best available chemotherapy; and assure that everyone who is healthy enough to get chemotherapy receives it. Under these assumptions, reaching optimistic goals for chemotherapy would have an almost immediate effect and would be the most effective way to lower the death rate by 2010. But without new chemotherapy approaches from translational research, the gains attributable to improved access to treatment remain relatively constant over time. (See the section on Chemotherapy for details on the improvements modeled).

After 2010, we can see that a higher rate of screening (blue bars) begins to have an impact on CRC mortality over and above the baseline projection, and surpasses that of chemotherapy by 2014. Screening in our models includes fecal occult blood tests (FOBT), sigmoidoscopy and colonoscopy. The impact is delayed because many of the problems discovered during screening would not have resulted in death for a number of years. Screening increases the chances of finding and removing pre-cancerous adenomas, as well as detecting and curing early stage colorectal cancer. (See the section on Screening for details on the tests modeled).

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