South African National Cancer Registry: Effect of withheld data from private health systems on cancer incidence estimates

Authors: E. Singh, J.M. Underwood, C. Nattey, C Babb, M. Sengayi, P. Kellet

Source: S Afr Med J 2015;105(2) 107-109

Summary:

Background: The National Cancer Registry (NCR) was established as a pathology-based cancer reporting system. From 2005 to 2007, private health laboratories withheld cancer reports owing to concerns regarding voluntary sharing of patient data.

Objectives: To estimate the impact of under-reported cancer data from private health laboratories.

Methods: A linear regression analysis was conducted to project expected cancer cases for 2005 – 2007. Differences between actual and projected figures were calculated to estimate percentage under-reporting.

Results: The projected NCR case total varied from 53 407 (3.8% net increase from actual cases reported) in 2005 to 54 823 (3.7% net increase) in 2007. The projected number of reported cases from private laboratories in 2005 was 26 359 (19.7% net increase from actual cases reported), 27 012 (18.8% net increase) in 2006 and 27 666 (28.4% net increase) in 2007.

Conclusion: While private healthcare reporting decreased by 28% from 2005 to 2007, this represented a minimal impact on overall cancer reporting (net decrease of <4%).