Prevention is better than cure, shows a research, which links policies aimed at restricting the use of chemicals with fewer cases of non-Hodgkin's lymphoma (nhl). The study, by Swedish oncologists, indicates that incidence of the cancer in Sweden decreased (0.8 per cent for men and 0.2 per cent for women) between 1991 and 2000 -- around 20 years after the use of chemicals associated with nhl was restricted. Lennart Hardell from the rebro University, and Mikael Eriksson from the Lund University, analysed data of the National Swedish Cancer Registry to arrive at their conclusion.
nhl is linked with three types of chemicals: phenoxyacetic acids and chlorophenols; organic solvents; and persistent organic pollutants. The cancer can develop decades after the exposure. Phenoxyacetic acids and chlorophenols were both banned in Sweden during the 1970s. Organic solvents were not banned, but occupational exposure was reduced.
The study also lends urgency to worldwide ratification of the Stockholm Convention -- other chemicals linked to nhl (polychlorinated biphenyls and dioxins) are among the 12 slated to be banned under the convention. The Swedish Environmental Protection Agency reports that the use of these chemicals peaked during the 1960s and 1970s, after which their environmental concentrations dropped significantly.
The Surveillance Epidemiology and End Results of the Maryland-based National Institute of Cancer indicate similar trends in the US. Between 1973 and 1990, the incidence of NHL in the country increased by 3.6 per cent per year. From 1990 to 1995, the increase was 1.6 per cent per year; but between 1995 and 1999, NHL incidence declined by 0.9 per cent for men, while women experienced a lower mortality rate. The incidence decreased approximately 20 years after most uses of the chlorophenoxy herbicide 2,4,5-T were banned in the nation.