Do Bed Nets Prevent Cancer?

By Philip R. Fischer, MD, DTM&H

Professor of Pediatrics, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN

SYNOPSIS: When used properly, bed nets prevent malaria in endemic areas. A new systematic review and a meta-analysis confirm that bed net use also is associated with a reduced incidence of Burkitt lymphoma in children in sub-Saharan Africa.

SOURCE: Schmit N, Kaur J, Aglago EK. Mosquito bed net use and Burkitt lymphoma incidence in sub-Saharan Africa: A systematic review and meta-analysis. JAMA Netw Open 2024;7:e247351.

In malaria-endemic regions of Africa, Burkitt lymphoma is a common childhood cancer. It has been etiologically linked to both Epstein-Barr virus infection and Plasmodium falciparum malaria.

In the 1980s, an uncontrolled mass antimalaria treatment trial suggested that treated patients were less likely to develop Burkitt lymphoma. Two hospital-based case-control studies demonstrated that having insecticide-treated bed nets in the home was associated with a potentially reduced risk of developing Burkitt lymphoma. However, on the other hand, a population-based study identified a higher risk of developing Burkitt lymphoma in children where either bed nets or residual insecticide spraying were used.

The incidence of malaria has gone down significantly during the past 20 years with increased emphasis on the appropriate use of insecticide-treated bed nets and on the use of artemesinin-based malaria treatment. The dramatic reductions in the number of cases of malaria typically have been attributed to the use of insecticide-treated bed nets, but whether this affects the risk of Burkitt lymphoma has been less well-studied. Thus, Schmit and colleagues carefully reviewed studies about the incidence of Burkitt lymphoma in sub-Saharan Africa before and after the introduction of widespread, large-scale use of insecticide-treated bed nets.

Using standard procedures for systematic reviews, Schmit and colleagues used cancer registries and published literature to identify Burkitt lymphoma incidence rates since 1990 in sub-Saharan African countries where malaria is endemic. Incidence rates were compared before and after insecticide-treated bed nets were used in each location.

From 13 published articles and 10 cancer registries comprising 5,700 cases of Burkitt lymphoma in patients up to 15 years of age, 76 time-specific and location-specific Burkitt lymphoma incidence rates were determined. Incidence rates of Burkitt lymphoma were 44% lower after the introduction of insecticide-treated bed nets (1.36 per 100,000 person-years before and 0.76 after). However, there was variation between the 17 countries for which data were available, and the incidence of Burkitt lymphoma actually rose with the use of insecticide-treated bed nets in one country (Mali) where there were statistical concerns for under-reporting of Burkitt lymphoma during the 10 years prior to initiation of widespread bed net use.

The authors recognized the possibility of incompletely accurate reporting of cancer in various regions of Africa. Nonetheless, they rightly suggested that improved insect control not only reduces the risk of malaria but also reduces the risk of Burkitt lymphoma.

COMMENTARY

Denis Burkitt’s pioneering in Uganda during the 1960s clearly established the link between the occurrence of Burkitt’s eponymous childhood lymphoma of the jaw and underlying immunity-stimulating malaria infections combined with a “second hit” of Epstein-Barr virus infection. Approximately three-fourths of African children with Burkitt lymphoma had Epstein-Barr infection.¹ (In North America, Burkitt lymphoma usually occurs in other body areas and is not associated with these predisposing infections.) By the time I was a medical student and met Denis Burkitt, Burkitt’s focus had moved on to cancer prevention and, specifically, how dietary adjustments could prevent colon cancer. (He admonished us students to increase fiber intake so that our stools would be “floaters” instead of “sinkers.”)

Now, nearly 60 years after Burkitt’s initial work on the epidemiology of childhood lymphoma, the work of Schmit and colleagues confirms that non-pharmacologic strategies, specifically bed net use, can lower the risk of Burkitt lymphoma. This finding should prompt ongoing efforts to implement malaria prevention strategies.

Of course, multiple strategies should be employed concurrently to reduce the risk of malaria and Burkitt lymphoma in children in Africa. New data suggest that a single subcutaneous monoclonal antibody (L9LS) dose provides safe protection against malaria in Africa with effectiveness against clinical malaria over six months (77%).² This is comparable to the protection provided in other settings by the increasingly used RTS,S/AS01 malaria vaccine series (35% over four years in areas of continual year-long malaria endemicity) and the R21/Matrix-M vaccine (75% over six to 12 months in areas with seasonal malaria).²

REFERENCES

1. Velavan TP, Kremsner PG. Use of insecticide-treated bed nets and incidence of Burkitt lymphoma. JAMA Netw Open 2024;7:e247358.
2. Kayentao K, Ongoiba A, Preston AC, et al. Subcutaneous administration of a monoclonal antibody to prevent malaria. N Engl J Med 2024;390:1549-1559.