Excellent performance of Hemoccult Sensa in organised colorectal cancer screening

Abstract

Background: Faecal occult blood (FOB) testing is the most commonly chosen approach in organised population-based colorectal cancer screening programmes throughout the world. Several FOB tests are available which differ in their test qualities. While immunological tests are gaining popularity due to their lower labour intensive analysis and higher standardisation, they are heat labile and more expensive. We studied the real-life experience of a large population-based, organised, screening programme in Israel which employs FOB testing with Hemoccult Sensa, a guaiac test with increased sensitivity that is similar to that of the immunological tests for cancer.

Methods: Clalit Health Services is the largest health care provider in Israel. All eligible insurees are actively invited to perform a free-of-charge, home-based, faecal occult blood test, using Hemoccult Sensa. All tests with positive results are followed up and information on colonoscopy, surgical procedures and pathology findings is collected.

Results: During an 18 month period (July 2007-December 2008) 382,792 FOBT tests (in 325,851 people) were performed by the target population, of them 85% Jews and 15% Arabs. Seven hundred and eighteen colorectal cancers and 2652 adenomas were detected. The overall test positivity rate in repeatedly-tested people was 4.2%. The overall detection rate of colorectal cancer in the subsequent tests was 1.7/1000 reflecting 91% of the expected period-incidence of CRC. 70% of the cancers were detected at stages Duke's B2 and lower. Left-sided cancers were detected at a significantly better stage than right-sided cancers (P<0.001). Detection rates among Arabs were somewhat lower than among Jews but the screening programme led to a meaningful increase in national incidence rate in this subgroup by detecting tumours that were otherwise asymptomatic.

Conclusion: The Clalit organised colorectal cancer screening programme, using low cost Hemoccult Sensa, has reached the targets of very high detection rate of cancers, most of them at low stage while keeping a low positivity rate. This approach demonstrates an efficient field-tested alternative to other, more costly, screening options.