OPTIMAL COLORECTAL CANCER SCREENING TO BALANCE LIFE-YEAR SAVINGS AND COSTS

  

Purpose: Most studies on the performance of colorectal cancer (CRC) screening policies considered only the common screening policies. Our purpose is to determine the optimal colonoscopy screening policies, which balance expected total QALYs and associated costs, among all possible policies.     

Method: We use a Markov decision model to compare the performances of colonoscopy screening policies for asymptomatic average-risk, higher-risk, and post-CRC (with CRC history) males and females at different ages. We determine the policies that maximizes “w * expected total QALYs – total expected costs”, where “w” refers to the dollar value of life. By varying the dollar value of life, we develop a range of colonoscopy screening policies on the efficiency and economy spectrum. In the model, we take into account the costs associated with screening, complications, CRC treatment, and terminal care. We use clinical data from Mayo Clinic, SEER database, and literature to obtain the cost and CRC progression parameters. We estimate the parameters of polyp-to-CRC progression and mortality from undetected CRC via calibration.   

Result: Our results show that if 50-year-old average-risk males undergo colonoscopy screening complying with the current guidelines, they experience 28.55 years of QALYs and undergo 3.5 colonoscopies in average. If they comply with the optimal policy for w = $100K, then the corresponding results are 28.59 years and 5.67 colonoscopies with an extra cost of $804. The following table shows the percent improvements of the optimal policies for different dollar value of life as compared to the current guidelines. The optimal policies suggest more frequent screening than the current guidelines for 50-year-old average-risk, higher-risk, and post-CRC patients. The optimal policies decrease the CRC risk and mortality up to 66% and 75%; and lead to improvements in QALYs. Note that, for some w values, such as $25K in the average-risk males, the optimal policies are associated with higher QALYs and less cost.         

Conclusion: Recent surveys showed that many clinicians recommend more frequent colonoscopy screening than the guidelines, which is criticized in the literature. Our results provide justification for the clinicians, who practice shorter screening intervals. Furthermore, we show that more efficient and economic screening policies can be found by evaluating all possible screening policies. Therefore, more research is needed towards this direction.