Multiple myeloma in the United States, 1950--1975

Multiple myeloma

Multiple myeloma (MM) is a haematological lymphoid malignancy involving tumoural plasma cells and is usually characterized by the presence of a monoclonal immunoglobulin protein. MM is the second most common haematological malignancy, with an increasing global incidence. It remains incurable because most patients relapse or become refractory to treatments. MM is a genetically complex disease with high heterogeneity that develops as a multistep process, involving acquisition of genetic alterations in the tumour cells and changes in the bone marrow microenvironment. Symptomatic MM is diagnosed using the International Myeloma Working Group criteria as a bone marrow infiltration of ≥10% clonal plasma cells, and the presence of at least one myeloma-defining event, either standard CRAB features (hypercalcaemia, renal failure, anaemia and/or lytic bone lesions) or biomarkers of imminent organ damage. Younger and fit patients are considered eligible for transplant. They receive an induction, followed by consolidation with high-dose melphalan and autologous haematopoietic cell transplantation, and maintenance therapy. In older adults (ineligible for transplant), the combination of daratumumab, lenalidomide and dexamethasone is the preferred option. If relapse occurs and requires further therapy, the choice of therapy will be based on previous treatment and response and now includes immunotherapies, such as bi-specific monoclonal antibodies and chimeric antigen receptor T cell therapy.

Rapidly changing myeloma epidemiology in the general population: Increased incidence, older patients, and longer survival

The incidence of multiple myeloma is characterized by a steep increase with advancing age. Dramatic improvements in survival have been reported in clinical trials; however, elderly patients are generally underrepresented in these. The aims of this study are to review patterns of incidence and survival in multiple myeloma in the general population. We searched PubMed for population-based studies on trends in incidence and survival published between January 1, 2000 and June 30, 2017 and based on regional or national cancer registries and report the following results of the review. The age-adjusted incidence of multiple myeloma has increased during the second half of the twentieth century in some countries but remained stable in areas with high case ascertainment and access to universal medical care. The crude incidence is increasing globally due to an aging population. Survival rates have improved, and 5-year relative survival rates are now around 50% and over 60% in patients 65-70 years or younger. Preliminary data suggest a 3-fold increase in the prevalence of multiple myeloma. We conclude that the number of multiple myeloma patients is increasing in the general population due to (i) aging populations and (ii) more patients living longer due to modern drugs.

Multiple myeloma and occupational exposures: a population-based case-control study

OBJECTIVE

The present study aims to identify occupational exposures associated with incidence of multiple myeloma (MM).

METHODS

A population-based case-control study of MM (ICD-9 203) was conducted among Canadian males, with a total of 342 cases and 1506 controls contributing to the final analyses. Conditional logistic regression was used to estimate odds ratios (OR) and confidence intervals (CI), stratifying by age groups and province of residence.

RESULTS

Based on the most parsimonious multivariable model, the following variables were significantly associated with an increased incidence of MM: exposure to coal dust (OR 1.7, 95% CI 1.2-2.4), long-held occupations as a carpenter (OR 3.2, 95% CI 1.4-7.1) or a machinist (OR 2.4, 95% CI 1.0-5.8); and immediate family member having been previously diagnosed with certain cancers (OR 1.4, 95% CI 1.1-1.8).

CONCLUSION

In this study of Canadian men, a higher risk of MM may be associated with exposure to coal dust, long-held occupations as a carpenter or machinist, and a positive family history of cancer.

Level of education and the risk of lymphoma in the European prospective investigation into cancer and nutrition

INTRODUCTION

Lymphomas belong to the few cancer sites with increasing incidence over past decades, and only a few risk factors have been established. We explored the association between education and the incidence of lymphoma in the prospective EPIC study.

MATERIALS AND METHODS

Within 3,567,410 person-years of follow-up, 1,319 lymphoma cases [1,253 non-Hodgkin lymphomas (NHL) and 66 Hodgkin lymphomas (HL)] were identified. Cox proportional hazard regression was used to examine the association between highest educational level (primary school or less, technical/professional school, secondary school, university) and lymphoma risk.

RESULTS

Overall, no consistent associations between educational level and lymphoma risk were observed; however, associations were found for sub-groups of the cohort. We observed a higher risk of B-NHL (HR = 1.31, 95% CI = 1.02–1.68; n = 583) in women with the highest education level (university) but not in men. Concerning sub-classes of B-NHL, a positive association between education and risk of B cell chronic lymphatic leukaemia (BCLL) was observed only in women. In both genders, the risk of diffuse large B cell lymphoma (DLBCL) was significantly lower for subjects with university degree (HR = 0.46, 95% CI = 0.27–0.79) versus lowest educational level. No association was found for HL.

CONCLUSION

We could not confirm an overall consistent association of education and risk of HL or NHL in this large prospective study; although, education was positively related to the incidence of BCLL and B-NHL (in women) but inversely to incidence of DLBCL. Due to limited number of cases in sub-classes and the large number of comparisons, the possibility of chance findings can not be excluded.

Patterns of multiple myeloma during the past 5 decades: stable incidence rates for all age groups in the population but rapidly changing age distribution in the clinic

OBJECTIVE

To define age-adjusted incidence trends in multiple myeloma (MM) in a well-characterized population during a long period, given that some, but not all, studies have reported increasing MM incidence over time and that clinical experience from some centers suggests an increased incidence mainly in younger age groups.

PATIENTS AND METHODS

We identified all patients (N=773) with MM diagnosed in Malmö, Sweden, from January 1, 1950, through December 31, 2005. Using census data for the population of Malmö, we calculated age- and sex-specific incidence rates. Incidence rates were also calculated for 10-year birth cohorts. Analyses for trends were performed using the Poisson regression.

RESULTS

From 1950 through 2005, the average annual age-adjusted (European standard population) incidence rate remained stable (Poisson regression, P=.07 for men and P=.67 for women). Also, comparisons between 10-year birth cohorts (from 1870-1879 to 1970-1979) failed to detect any increase. Between 1950-1959 and 2000-2005, the median age at diagnosis of MM increased from 70 to 74 years, and the proportion of newly diagnosed patients aged 80 years or older increased from 16% to 31%.

CONCLUSION

Our finding of stable MM incidence rates for all age groups during the past 5 decades suggests that recent clinical observations of an increase of MM in the young may reflect an increased referral stream of younger patients with MM, which in turn might be a consequence of improved access to better MM therapies. Importantly, because of the aging population, the proportion of patients with MM aged 80 years or older doubled between 1950-1959 and 2000-2005.

Oncologic progression of bone plasmacytomas to multiple myeloma

PURPOSE

To evaluate the clinical aspects, diagnoses, prognostic factors, and percent progression of plasmacytoma to multiple myeloma.

MATERIALS AND METHODS

103 medical records of patients suspected of plasmacytoma were surveyed covering the period between 1950 and 1998, and 30 were selected for analysis. Patients were classified into 2 groups: patients who did (n = 17) and did not (n = 13) progress to multiple myeloma. Comparative statistics regarding a variety of clinical aspects were developed.

RESULTS

Patients who progressed to multiple myeloma were younger than those who did not (52.3 +/- 2.6 vs 62.6 +/- 3.4 years; mean +/- SEM; P = 0.02). There were no significant differences in gender between groups. A higher incidence of multiple recurrence was observed in patients who progressed to multiple myeloma (75%, P = 0.049). Both groups showed a prevalence of vertebral column injuries. No significant differences were found between groups regarding the disease period (from the onset of symptoms until diagnosis) (P = 0.20) and survival (P = 0.34). The average time to progression from plasmacytoma to myeloma was 41 +/- 39 months (mean +/- SD), and the progression rate was 57%.

CONCLUSION

Patients who progressed to multiple myeloma were younger than those who did not. No significant differences were found between groups regarding sex, time from symptom onset to diagnosis, and survival time. In both groups, the most affected anatomic location was the vertebral column, and most affected sex was male. The average time to progression to multiple myeloma was 41 months. It was not possible to determine the factors that influenced the survival of patients with plasmacytoma or for those who progressed to multiple myeloma.

An overview of monoclonal gammapathies

The neoplastic proliferation of single clones of plasma cells causes synthesis of very large amount of monoclonal immunoglobulins consisting of only one type of heavy either the gamma, alpha, mu, delta or epsilon chain or only kappa or lambda light chains. Each monoclonal immunolobulin differs idiotypically from each other. These monoclonal immunoglobulins are also called paraproteins and are frequently associated with a broad heterogeneous group of plasma cell dyscrasias. Occasionally their presence is observed in a few benign conditions and in old age. In the present review a detailed account of different types of monoclonal gammapathies are described.

Socioeconomic status and multiple myeloma among US blacks and whites

OBJECTIVES

This study examined the relation between socioeconomic status (SES) and risk of multiple myeloma among Blacks and Whites in the United States.

METHODS

This population-based case-control study included 573 cases (206 Blacks and 367 Whites) with new diagnoses of multiple myeloma identified between August 1, 1986, and April 30, 1989, and 2131 controls (967 Blacks and 1164 Whites) from 3 US geographic areas. Information on occupation, income, and education was obtained by personal interview.

RESULTS

Inverse gradients in risk were associated with occupation-based SES, income, and education. Risks were significantly elevated for subjects in the lowest categories of occupation-based SES (odds ratio [OR] = 1.71, 95% confidence interval [CI] = 1.16, 2.53), education (OR = 1.36, 95% CI = 1.06, 1.75), and income (OR = 1.43, 95% CI = 1.05, 1.93). Occupation-based low SES accounted for 37% of multiple myeloma in Blacks and 17% in Whites, as well as 49% of the excess incidence in Blacks. Low education and low income accounted for 17% and 28% of the excess incidence in Blacks, respectively.

CONCLUSIONS

Our results indicate that the measured SES-related factors account for a substantial amount of the Black-White differential in multiple myeloma incidence.

Increasing multiple myeloma mortality among the elderly: a manifestation of aging and differential survival

Increasing multiple myeloma incidence and mortality among the elderly in industrialized nations has been attributed to associated environmental carcinogens. Age-specific multiple myeloma mortality rates in the United States from 1968 to 1989 were analyzed using the Strehler-Mildvan modification of the Gompertz relationship between aging and mortality. The results suggest that worsening environmental influences are not responsible for increasing multiple myeloma mortality among the elderly. Differential survival, a concept originally popularized by Charles Darwin, and its effect upon the surviving gene pool in an aging population is an alternative explanation for increasing multiple myeloma incidence and mortality in the elderly.

The epidemiology of AL and AA amyloidosis

The limited available epidemiological information on AL amyloidosis suggests that there may be differences between population-based studies and case series data with respect to variables such as age and racial patterns. Much more work in this area is required before specific aetiologic hypotheses can be tested. Most available data to approximate the epidemiology of AA amyloidosis are derived from autopsies. Most patients with AA amyloidosis die from causes other than amyloidosis, therefore mortality data based on death certificates is of limited value in AA amyloidosis. Case ascertainment in autopsy studies may be difficult due to the frequent lack of adequate histological controls. Establishment of registries for both AL and AA amyloidosis would facilitate epidemiological research in these disorders.

Prognostic factors in multiple myeloma

The pretreatment characteristics of 265 multiple myeloma patients treated between 1977 and 1983 were evaluated as potential prognostic factors for survival. Patients whose diagnosis was based on bone marrow plasmacytosis (greater than 30%) were noticed to have poorer survival (P less than 0.001). Although classification of patients according to stage has traditionally been used to identify prognostic groups, differences in survival were noted only between Stage III and Stage I or II patients using one of two common staging systems. Multivariate analysis using Cox's proportional hazards model identified the following prognostic factors in order of importance: plasmacytosis (hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.49 to 3.27), hypercalcemia (HR = 1.68, CI = 1.22 to 2.32), hypoalbuminemia (HR = 1.51, CI = 1.15 to 1.99), alkaline phosphatase (HR = 1.62, CI = 1.18 to 2.23), hyperuricemia (HR = 1.46, CI = 1.09 to 1.96), and renal insufficiency (HR = 1.48, CI = 1.08 to 2.04). All patients were followed from 2 to 7.5 years and 130 (49%) survived over 2 years. Logistic regression analysis demonstrated that hyperuricemia, hypoalbuminemia, renal insufficiency, plasmacytosis, gender, alkaline phosphatase, and hypercalcemia were significant predictors of 2-year survival. Knowledge of these factors could be of value in predicting prognosis and planning therapy in patients with multiple myeloma.

Cancer risks in painters: study based on the New Zealand Cancer Registry

Painters are exposed to a range of complex chemical mixtures which include organic solvents and dye products with known carcinogenic and mutagenic potential. Trade painters or those manufacturing paints and coatings have increased rates of non-malignant diseases and cancers; including lung cancer, acute leukaemia, bladder cancer, and cancers of the oesophagus, larynx, biliary system, liver, skin, and large bowel. A series of case-control studies of painters, based on the New Zealand Cancer Registry, are presented. These concerned 19,904 male patients registered for the period 1980-4 who were aged 20 or older at the time of registration. For each cancer site studied, the registrants for all other cancer sites formed the control group. Three cancer sites were associated with work as a painter--namely, bladder tumours (odds ratio (OR) 1.52, 95% confidence interval (95% CI) 1.00-2.31), kidney and other urothelial tumours (OR 1.45, 95% CI 0.85-2.50), and multiple myeloma (OR 1.95, 95%, CI 1.05-3.65). Risks for multiple myeloma were greater among car or spray painters and signwriters (OR 2.81) compared with construction and general painters (OR 1.80). No increased risk was found for leukaemia or for respiratory, biliary, skin, or gastrointestinal cancers.

Cancer risk following pernicious anaemia

A computer-based file of all Veterans Administration (VA) hospitalisation records for the period 1969-1985 was used to identify and follow for cancer development a cohort of 5,161 white males with pernicious anaemia. A total of 34,915 person-years were accrued, with an average length of follow-up of 6.8 years. A total of 481 cancers were diagnosed, slightly higher than the number expected (SIR = 1.2). Significant excesses were observed for cancers of the buccal cavity and pharynx (1.8) and stomach (3.2), and for melanoma (2.1), multiple myeloma (2.1), myeloid leukaemia (3.7) and other and unspecified leukaemia (4.0). Although the excess for stomach cancer was highest in the first year after diagnosis in a VA hospital, risks of 2-fold or greater persisted throughout the study period. The majority of leukaemias occurred in the first year of follow-up, but some excess risk continued beyond this time. The elevated risk of buccal and pharyngeal cancers may relate to heavy alcohol intake among this population, although risks remained high even when the cohort was restricted to patients without an admission for alcoholism. Although an elevated risk of stomach cancer among pernicious anaemia patients is consistent with most previous surveys, the low absolute risk suggests that the cost-effectiveness of intensive screening should be reassessed.

A case-control study of multiple myeloma nested in the American Cancer Society prospective study

Among the subjects enrolled in the American Cancer Society Cancer Prevention Study II, a large nation-wide prospective study, 282 died from multiple myeloma (MM) during the first 4 years of follow-up. These were divided into incident cases who were initially free from disease and prevalent cases who reported MM or related symptoms at the time of enrollment. For each case, 4 controls matched for age, sex, ethnic group and residence were randomly selected. Previous history of diabetes [odds ratio (OR) = 2.0] and employment as farmer (OR = 2.7) were the risk factors consistently suggested by the results of the analysis. The risk associated with farming showed a linear trend with duration of exposure. Pesticide or herbicide exposure was not a risk factor per se but, when combined with farming, it increased the OR to 4.3. Low education, occupational exposure to dyes, and employment in a bank, on the railroad or as a maid were also suggested risk factors, but either they were not statistically significant or they were based on small numbers of exposed subjects. No association between MM and asbestos exposure was observed.

Trends in the incidence of multiple myeloma in Denmark 1943-1982: a study of 5500 patients

The incidence of multiple myeloma in Denmark during the period 1943-82 was examined, based on the files of the Danish National Cancer Registry. A total of 5535 patients (3023 male and 2512 female) were registered. Over the period 1943-62 the incidence increased 2- to 3-fold for both men and women, but the increase in men was steeper and was seen several years before the increase in women in all 5-yr age groups from 50 to 75 yr of age. This pattern would be compatible with an impact of environmental factors. The increase, also percentagewise, rose with increasing age. Since 1963 the incidence has been virtually stable with a possibly decreasing trend during the latest 5- to 10-yr period.

Systemic treatment of cancer in the elderly

The goal of this review is to provide a readable and exhaustive reference in three major areas of geriatric oncology: complications of chemotherapy and radiotherapy, responsiveness of cancer to systemic treatment, social issues in the care of elderly patients with terminal illnesses. The conclusions of this study are: 1. Progressive deterioration of renal function is the most consistent change of aging. Adjustment of doses of renally excreted drugs to individual creatinine clearance may prevent life-threatening myelotoxicity in the elderly. 2. Intensive chemotherapy regimens (acute leukemia, non Hodgkin's lymphoma) cause more serious and prolonged myelotoxicity in the elderly. Elderly are more susceptible than younger patients to cardiotoxicity and central and peripheral neurotoxicity. Age is a poor predictor of complications in other organs or systems. 3. The prognosis of patients with Hodgkin's disease worsens with aging, possibly due to increased prevalence of mixed cellularity histology. It is controversial whether the prognosis of other neoplasias is poorer. Prognosis is not age-related in multiple myeloma. In general, elderly in good performance status may benefit from systemic cancer treatment to the same extent as younger patients, except for Hodgkin's disease. 4. The Informal Support Network, epitomized by the family, appears the most suitable environment to care for the elderly with cancer.

Plasma cell dyscrasias: current status

This is a review of the current status of the monoclonal gammopathies (plasma cell dyscrasias). We begin with the recognition of a monoclonal protein in serum and urine. We briefly discuss the differential diagnosis of the monoclonal gammopathies. Clinical and laboratory findings as well as the management of multiple myeloma are addressed. Future approaches for the treatment of myeloma are provided. The variant forms of multiple myeloma, including smoldering myeloma, plasma cell leukemia, nonsecretory myeloma, IgD myeloma, osteosclerotic myeloma, solitary plasmacytoma of bone, and extramedullary plasmacytoma, are briefly reviewed. Diagnosis and treatment of Waldenström's macroglobulinemia are presented. The recognition and differential diagnosis of the heavy-chain diseases (gamma, alpha, and mu) are included. Monoclonal gammopathy of undetermined significance ("benign" monoclonal gammopathy) is presented in detail. Amyloidosis is not included in this review.

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 and engine exhausts, fresh wood, and creosote: a case-referent study

The effect of potential risk factors for multiple myeloma was evaluated in a case-referent study encompassing 131 cases and 431 randomized referents, all alive. Information on exposure was obtained with questionnaires mailed to the subjects. An analysis of the material by means of the Miettinen confounder score technique resulted in a few rate ratios significantly exceeding unity--namely, occupational exposure to engine exhausts, creosote, and fresh wood. In view of other studies that suggest ionizing radiation as a risk factor, it was somewhat surprising that low-level gamma radiation from background exposure was less common among the cases than the referents.

Multiple myeloma in Northern Israel, 1970-1979

From 1970 to 1979, multiple myeloma was diagnosed in 184 residents of Northern Israel. The data were analyzed for variations by demographic factors, ethnicity, country of origin, and urban/rural residence areas. The average annual age-adjusted incidence rate per 100,000 residents was 1.78. The rates for males and females were 2.1 and 1.46/10(5) person-years, respectively. The male to female incidence ratio was 1.44:1.0. The average incidence rate was significantly higher for Jews than for Arabs and was higher for European Jews than for Afro-Asians or native Israelis. Urban areas had significantly higher rates than rural areas. A statistically significant increase in the incidence rates was demonstrated for the years 1975 to 1979 compared to the period 1970 to 1974. The increase was evident in all population categories, but was particularly prominent in females, the Jewish population, urban areas, and in the oldest age group. The results of the current study suggest that both culturally derived factors and industrial environment may play a role in the etiology of multiple myeloma.

Multiple myeloma in Western Australia: a case-control study in relation to occupation, father's occupation, socioeconomic status and country of birth

A death-certificate-based case-control study was undertaken covering 249 patients with multiple myeloma diagnosed in Western Australia from 1975 to 1984 whose deaths were registered in Western Australia in the same period (73.4% of the total diagnosed) and 996 control decedents who were matched to the cases by age, sex and death registration district. Death from multiple myeloma was associated with both farming [odds ratio (OR) 1.44 with 95% confidence interval (CI) 0.81-2.55] and woodworking (OR 1.70 with 95% CI 0.67-4.31) but not with farming as the father's occupation (OR 0.96 with 95% CI 0.66-1.41). It was also more frequent in migrants to Australia than in native-born Australians (OR 1.31 with 95% CI 0.99-1.74) particularly those born in England (OR 1.57 with 95% CI 1.11-2.42) and Italy (OR 2.02 with 95% CI 1.09-3.74). An apparent excess of multiple myeloma in all rural residents appeared to be due to bias introduced by matching for death registration district, as rural residents dying from multiple myeloma were more likely to die and have their deaths registered in the city than other rural residents. A conditional logistic regression analysis showed the above associations to be substantially independent of one another.

Age and the treatment of multiple myeloma. Southeastern Cancer Study Group experience

To determine the impact of age upon the response to treatment, survival, and toxicity of chemotherapy for multiple myeloma, the results of a large cooperative group trial were examined. Patients were randomly assigned to induction therapy with either carmustine, cyclophosphamide, and prednisone or melphalan and prednisone; patients with response received two years of treatment. The age distribution of patients in this trial compared with the incidence figures from the Surveillance Epidemiology and End Results (SEER) study shows a degree of under-representation of the oldest patient groups. Prognostic factors were evenly distributed over the age range and treatment groups. Older patients had responses and survival rates equivalent to younger patients and with both treatment regimens regardless of prognostic factor characteristics. Hematologic toxicity was no greater for the older group in either regimen despite the presence of a nitrosourea in one. Gastrointestinal toxicity was increased in the older patients who received the regimen of melphalan and prednisone. The study suggests that in myeloma and perhaps other such chemotherapy-responsive malignancies treated with moderately intense chemotherapy, without bone marrow ablation, elderly and younger patients have similar outcomes.

Socioeconomic status and risk of multiple myeloma

A case control study was conducted to test the hypothesis that socioeconomic status is positively associated with multiple myeloma incidence. One hundred and fifty-three myeloma cases and 459 controls were identified at the Duke University Medical Center at Durham, North Carolina. Study members were interviewed regarding indicators of socioeconomic status. The association of myeloma with family income (current and highest), education, occupation, home ownership, dwelling size, and an index of crowding in the home was examined by estimating relative risks. Among these indicators, only home ownership showed any association with multiple myeloma incidence (RR = 1.6, 95% CI: 1.0-2.6). The association of multiple myeloma with socioeconomic status that has been seen in earlier studies may have been due to underascertainment of disease in less advantaged groups. This association is disappearing as access to health care becomes more uniform across socioeconomic groups.

Comparison of trends in the incidence of multiple myeloma in Malmö, Sweden, and other countries, 1950-1979

Dramatic increases in mortality from multiple myeloma have been reported in the United States and the United Kingdom over the past three decades. To assess what fraction of this increase, if any, might be attributable to a change in the incidence of this disease, we examined the incidence of multiple myeloma during 1950 to 1979 in Malmö, Sweden, a city chosen because of its medical community's longstanding interest in this disease. The average annual incidence rates per 100,000 population were 4.9 for males and 3.7 for females (adjusted to the European age-standardized population). These rates are among the highest in the world. Unlike secular trends for myeloma in the United States and the United Kingdom, where large increases in mortality rates have been reported, the rates in Malmö have increased only slightly, and the increase was restricted to males, suggesting the possibility of environmental causes. We suggest that the rates in Malmö may represent the asymptote of myeloma's incidence that will be approached in other white populations as case ascertainment among them becomes complete.

Cancer risks associated with agriculture: epidemiologic evidence

Despite their generally favorable mortality experience, general occupational surveys of farmers suggest they have elevated risks of cancer of the lymphatic and hematopoietic systems, stomach, prostate, brain, and skin. Since farmers often serve in the role of mechanic, carpenter, welder, pesticide applicator, and veterinarian, they may be exposed to many potentially hazardous substances. The types and levels of exposures have been discussed by others earlier in the program. The evidence is strongest for the association between farming and risk of leukemia. However, the specific leukemogenic agent or agents have yet to be identified. Leukemia excesses among poultrymen and dairy farmers suggest involvement of zoonotic viruses, while associations with crop production is more indicative of pesticide usage. The associations regarding other cancers (i.e., Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, soft-tissue sarcoma, and cancers of the stomach, brain, and prostate) are even less clear. However, the Swedish reports of high risk of soft-tissue sarcomas and lymphomas among persons exposed to herbicides is particularly disconcerting and underscores the urgent need for similar epidemiologic studies in the U.S. Several case-control interview studies are underway that should help clarify the role of agricultural factors in the origin of various cancers. NCI is sponsoring studies of leukemia and non-Hodgkin's lymphoma among men from Minnesota and Iowa. Detailed information on farm practices and pesticide usage is being gathered. A study of soft-tissue sarcoma, Hodgkin's disease, and non-hodgkin's lymphoma also has just been initiated. This investigation is located in Kansas, a major wheat producing area. A wheat producing area was selected because herbicides are more heavily used on this crop than insecticides. The major objective of this project is to evaluate the role of herbicides in the origin of these cancers. A case-control study of brain cancer has also recently been initiated. Although this study focuses on contact with petrochemicals, a complete work history will be obtained and would note any farm experience. These data may help clarify the reported association between brain cancer and farming.

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.