Multiple myeloma in South African blacks

Characteristics and outcomes of patients with multiple myeloma at the Uganda Cancer Institute

PURPOSE

Data on multiple myeloma (MM) in sub-Sahara Africa is scarce. In Uganda, there is a progressively increasing incidence of MM over the years.

METHODS

We performed a retrospective study on 217 patients with MM at the UCI using purposive sampling method. The objectives of the study were to determine the clinical characteristics, treatment outcomes, 5 year overall survival and predictors of survival of patients with MM at the UCI from 01 January 2008 to 31 December 2012.

RESULTS

There were 119 (54.8%) males; the mean(SD) age of the study population at presentation was 59(12.8) years; 183(84.3%) patients presented with bone pain, and 135 (61.9%) had skeletal pathology; 186(85.3%) were HIV negative, and 152(70%) had Durie-Salmon stage III. The median overall survival was 2.5 years, (95% CI, 0.393-0.595); factors significantly associated with worse survival were Durie-Salmon stage III disease, HR=5.9, 95% CI (1.61 - 21.74; P=0.007) and LDH >225 U/L HR=3.3, 95% CI (0.57 - 5.92; P=0.029).

CONCLUSION

Most patients with multiple myeloma at the UCI were diagnosed at a relatively young age, presented with late stage disease and bone pain, and had a shorter survival time. Factors associated with worse survival were Durie-Salmon stage III and LDH >225 U/L.

Myeloma aetiology and epidemiology

Recently there have been substantial improvements in our understanding of the biology of myeloma. These findings have important implications for aetiological studies aimed at defining the causative factors for myeloma. Myeloma is closely related to monoclonal gammopathy of unknown significance (MGUS), which is now recognized to be very common in the older population. The epidemiology of these conditions is presented and discussed in the context of the genetic factors governing both the risk of developing MGUS or of transformation to myeloma. Biological studies support a role for aberrant class switch recombination early in the natural history of myeloma suggesting that factors in the environment may interact with this mechanism to increase myeloma risk. Case-control and cohort studies have identified several known and suspected environmental exposures. These exposures include high doses of ionizing radiation, and occupational exposure in the farming and petrochemical industries. The data supporting these associations are presented and discussed in the context of the molecular mechanisms underlying these exposures. In particular DNA damage occurring as a consequence could readily interact with the class switch recombination process to increase the risk of chromosomal translocations, oncogene deregulation and malignant transformation. A further hypothesis, which has been extensively investigated, is the role of chronic immune/antigenic stimulation and the risk of myeloma. This concept is difficult to explain in the context of our current immunological concepts. The data supporting the association and how molecular epidemiological studies using genetic variants in cytokine genes are allowing us to revisit this concept are discussed in detail.

Connective tissue responses in blacks in relation to disease: further observations

Additional information is presented in support of the hypothesis (Polednak: Am. J. Phys. Anthropol. 41:49-58, 1974) that in some black populations certain connective-tissue responses, which are involved in protection against infection and repair after injury, also may predispose to specific chronic diseases. These diseases include some autoimmune disorders (i.e., systemic lupus erythematosus, sarcoidosis, and scleroderma) and various benign and malignant tumors involving connective-tissue cells. Complex interactions between genetic factors (HLA and non-HLA loci) and environmental agents may be involved both in the etiology of these autoimmune diseases and in population differences in the incidence of these diseases. A framework is reviewed whereby cellular responses to infectious agents, involving chiefly immunoglobulin-producing cells and macrophages, may have consequences in terms of pathogenesis of specific chronic diseases more common in some black populations. The possible role of natural selection in maintaining some of these diseases is also considered, along with the need for involvement of biomedical anthropologists in their investigation.

Multiple myeloma in cosmetologists

In an hypothesis-generating activity, data in a population-based cancer registry were analyzed according to occupation and industry. The number of cases of multiple myeloma was found to be excessive for females in the occupation "cosmetologists, hairdressers and manicurists." Race did not explain the excess. People in this occupation have potential exposure to a number of chemicals that produce mutations in bacteria. Studies should be done to investigate the hypothesis that these chemicals cause multiple myeloma in cosmetologists.

Multiple myeloma in the United States, 1950--1975

A total of 68,400 whites and 10,533 nonwhites were reported to have died from multiple myeloma (MM) in the continental United States between 1950 and 1975 (excluding 1972 because of incomplete case ascertainment). Age-adjusted mortality rates for nonwhites were approximately twice as high as for whites. During the 25-year period of this survey, there was a twofold to threefold increase in MM mortality. The increase was seen in both races, but was greater in nonwhites than whites and primarily occurred in people over 55 years of age. The increases were uniform in all geographic regions and urban/rural categories. MM mortality from 1950--1969 was correlated with geographic, demographic, and occupational factors at the county level. The rates were highest in the far west and mid-central regions for whites and in the northeast for nonwhites. Urban areas had the highest rates and rural areas had the lowest, and positive associations were seen with indices of socioeconomic level and the percentage of residents with Scandinavian ancestry. For white males, MM mortality rates were elevated in areas with high petroleum and paper production, and a slight increase was seen in furniture manufacturing areas.