What is the current status of quality-adjusted ratio and cost-effectiveness of screening for Barrett's cancer in males and females?
A.N. Kingsnorth (Liverpool)
Screening for gastrointestinal cancer is controversial and contributes relatively little to overall reduction in cancer mortality, although it may have an important impact on some tumour sites [1, 2]. The International Union against Cancer (UICC) concluded that the most effective way to evaluate the impact of screening was by randomized controlled trials . It was also concluded that the fall in cancer mortality in recent years can be attributed in part to screening programs. Quantitative approaches to evaluation of screening programs include mortality as being the initial evaluation, then the degree to which diagnosis is advanced (in time and stage of the disease), and the ability to identify presymptomatic lesions.
The dynamics of screening are important. There are methodological obstacles in proving benefit. Also the responsibilities and risks which intervention in a healthy population entails can be underestimated, and the benefits for early detection have only been successful to date for breast cancer.
The requirements of a screening program include the following:
1) a specific and sensitive method for early detection;
2) appropriate treatment options that have an impact on the natural course of the disease;
3) side effects are tolerable even to patients who have no benefit from early detection;
4) continuous quality control with repeated scientific evaluations when new therapeutic approaches/preventive measures become available;
5) cost-benefit analysis must underlie health policy decisions once favourable scientific data become available;
6) validation by an appropriate statistical assessment.
The costs of screening can be enormous . It has been estimated that for breast cancer the annual cost per life "saved" is £558,000. On the basis of these figures Wright and Mueller recommended that since the benefit achieved is marginal, the cost enormous, harm substantial, public funding for breast cancer screening in any age group is not justifiable.
The cost of screening for Barrett's cancers depends to a large extent on the number of cases detected in proportion to patient years of surveillance . Numerous publications in the world literature indicate that this ratio varies between one cancer detected for each 48-441 patient years of follow-up. We have recently demonstrated (unpublished data) that for men 1 cancer is detected for 59 patient years of follow up and for women 1 cancer is detected for 167 years of follow up. This indicates an approximately 3 fold increased cost for surveillance in women as compared to men.
Provenzale recently published a guide for surveillance in patients with Barrett's esophagus (BE) with particular reference to quality adjusted life expectancy and cost-effectiveness . The conclusions were based on the hypothesis that epidemiological data and cell growth kinetics of esophageal tumors suggested a preclinical asymptomatic phase of 4-5 years. Also the annual incidence of cancer was 1.3% and a randomized control trial of surveillance was not feasible because it would require approximately 5,000 patients with ten year follow-up to detect a 50% reduction in cancer mortality.
A further estimate of the cost of surveillance of Barrett's cancers was calculated by Skinner .
Assuming the rate of detection of cancers is 1.3-1.6 per 100 patient-years of follow-up or 8 cancers per 5 years for 100 patients and assuming $1,000 per procedure, then the cost is $500,000 to detect 8 stage l/stage 2 cancers of which 6 of 8 will be expected to be cured. In the non-surveillance group 8 patients will develop dysphagia with stage 3 cancers out of 4 and 2 of 8 will survive for 5 years. The failures (2 in the surveillance group and 6 in the non-surveillance group) will run up costs of $50,000 each for chemotherapy and repeated admission. The net gain is $320,000, i.e. $80,000 per life year saved. Provenzale  estimated that the gain in life expectancy with surveillance was minimal because of the late age of presentation of Barrett's cancer. In a non-surveillance patient the medium life expectancy is approximately 10 months after diagnosis, whereas the life expectancy with surveillance gave an estimated increase in life expectancy of only 1.4-3.9 years. With a strategy of annual surveillance the cost per quality adjusted life year gained was $118,000. Therefore when costs are an important consideration endoscopy every 5 years increases life expectancy and makes the cost effectiveness more realistic.
In conclusion screening for Barrett's cancer is expensive and in each institution is a matter of central health policy rather than a medical decision. Although the cost is greater in women they should not be excluded from surveillance on the basis of gender alone.