Estimating the incidence of colorectal cancer in Sub-Saharan Africa: A systematic analysis

Abstract

Background: Nearly two-thirds of annual mortality worldwide is attributable to non-communicable diseases (NCDs), with 70% estimated to occur in low- and middle-income countries (LMIC). Colorectal cancer (CRC) accounts for over 600 000 deaths annually, but data concerning cancer rates in LMIC is very poor. This study analyses the data available to produce an estimate of the incidence of colorectal cancer in Sub-Saharan Africa (SSA).

Methods: DATA FOR THIS ANALYSIS CAME FROM TWO MAIN SOURCES: a systematic search of Medline, EMBASE and Global Health which found 15 published data sets, and an additional 42 unpublished data sets which were sourced from the IARC and individual cancer registries. Data for case rates by age and sex, as well as population denominators were extracted and analysed to produce an estimate of incidence.

Results: The crude incidence of CRC in SSA for both sexes was found to be 4.04 per 100 000 population (4.38 for men and 3.69 for women). Incidence increased with age with the highest rates in Southern Africa, particularly in South Africa. The rates of CRC in SSA were much lower than those reported for high-income countries.

Conclusion: Few health services in SSA are equipped to provide timely diagnosis and treatment of cancer in SSA. In addition, data collection systems are weak, meaning that the available statistics may underestimate the burden of disease. In order to improve health care services it is vital that accurate measurements of disease burden are available to policy makers.

Figure 1

Sources of data.

Figure 2

Search strategy.

Figure 3

Definition of colorectal cancer in data sets. ICD – International Classification of Diseases (World Health Organisation).

Figure 4

Geographical distribution of data sets. Additional 20 unpublished data sets came from South African Cancer Registry (not shown).

Figure 5

Active data sets active in study years.

Figure 6

Incidence of colorectal cancer by age groups for both sexes (A), men (B) and women (C).

Figure 7

Crude incidence of colorectal cancer by age group for both sexes (A), men (B) and women (C).

Figure 8

Annual crude incidence of colorectal cancer by African sub–region (per 100 000 population).

Figure 9

Crude incidence of colorectal cancer in South Africa (per 100 000 population) by ethnicity for 2000–2004.

Figure 10

Colorectal cancer by anatomical tumour site.

Figure 11

Presenting symptoms in colorectal cancer.

Figure 12

Duke's staging of the colorectal cancer.

Figure 13

Comparison of incidence of colorectal cancer (per 100 000 population) in Sub–Saharan Africa between hospital–based and population–based cancer registries.