Unexplained increases in cancer incidence in the United States from 1975 to 1994: possible sentinel health indicators?

Concentration, spatial distribution, and non-carcinogenic risk assessment of arsenic, cadmium, chromium, and lead in drinking water in rural areas of eight cities of West Azarbaijan province, Iran

Exposure to heavy metals through drinking water can cause significant adverse health effects. The aim of the present study was to investigate the concentration, spatial distribution, and assessment of non-carcinogenic risk attributed to exposure to arsenic (As), chromium (Cr), cadmium (Cd), and lead (Pb) in rural areas of eight cities of the West Azerbaijan province of Iran. Eighty-five water samples were taken from randomly selected drinking water wells in the rural areas, and the concentration of the heavy metals was measured by using standard methods. The concentration distribution maps were drawn, and the non-carcinogenic health risks for ingestion and dermal exposure pathways were calculated in four age groups (including infants, children, teenagers, and adults). According to the obtained results, arsenic is considered as the most worrying pollutant among the investigated heavy metals. The maximum measured concentration for arsenic was 371.9 μg/L, which is 37 times the maximum permissible limit. The results of the health risk assessment illustrate that exposure to heavy metals via dermal contact do not pose significant non-carcinogenic risks. However, the calculated non-carcinogenic risks for oral exposure to arsenic were very high and concerning. The highest hazard quotient for oral exposure to arsenic was related to rural of city G (82.64). It is recommended to take the necessary measures as soon as possible regarding the supply of safe drinking water in the studied areas.

Epidemiologic perspective on immune-surveillance in cancer

Common 'themes' in epidemiology related to cancer risk beg a comprehensive mechanistic explanation. As people age, risk for cancer increases. Obesity and smoking increase the risk for many types of cancer. History of febrile childhood diseases lowers the risk for melanomas, leukemias, non-Hodgkin's lymphoma (NHL), and ovarian cancer. Increasing number of ovulatory cycles uninterrupted by pregnancies correlate positively with breast, endometrial, and ovarian cancer risk while pregnancies and breastfeeding lower the risk for these cancers as well as cancers of the colon, lung, pancreas, and NHL. Chronic inflammatory events such as endometriosis or mucosal exposure to talc increase the risk for several types of cancer. Mechanisms so far considered are site specific and do not explain multiple associations. We propose that most of these events affect cancer immunosurveillance by changing the balance between an effective immune response and immune tolerance of an emerging cancer. We review recently published data that suggest that immune mechanisms underlie most of these observed epidemiologic associations with cancer risk.

Age-period-cohort analysis of cancers not related to tobacco, screening, or HIV: sex and race differences

OBJECTIVE

To identify trends in a residual category of cancers not typically associated with tobacco, screening, or human immunodeficiency virus (HIV) infection.

METHODS

For persons aged 20-84, we used sex- and race-specific age-period-cohort (APC) models to describe temporal patterns of incidence (1975-2004) and mortality (1970-2004) in the U.S. for a residual cancer category that excluded non-Hodgkin lymphoma, Kaposi sarcoma, and cancer of the oral cavity and pharynx, esophagus, pancreas, larynx, lung and bronchus, urinary bladder, kidney and renal pelvis, colon and rectum, prostate, female breast, and cervix uteri.

RESULTS

Age-specific incidence rose (0.1-0.9% per year, on average) in every sex-race group, with factors related to both time period and birth cohort membership appearing to accelerate the increases in women. Age-specific mortality fell (0.6-0.9% per year, on average) for black and white men and women, with the declines decelerating in white women but accelerating in the other sex-race groups. Extrapolations of APC models predicted higher age-adjusted incidence rates in white women (11%), black women (5%), and white men (4%) in 2005-2009, relative to 2000-2004, and lower rates in black men (-3%), accompanied by lower age-adjusted mortality rates in every sex-race group (-8% in black men, -3% in black women, -1% in white men, and -1% in white women).

CONCLUSIONS

The possibility that increased incidence in women over time reflects changes in underlying risks, diagnostic practices, or better case ascertainment should be actively explored. Declining mortality may signify improvements in cancer care.

Temporal and demographic patterns of non-Hodgkin's lymphoma incidence in Pennsylvania

Our study analyzed temporal and demographic patterns of non-Hodgkin's lymphoma (NHL) incidence in Pennsylvania and compared Pennsylvania time trends with national trends. Joinpoint and age-period-cohort analyses summarized sex- and race-specific NHL incidence time trends between 1985 and 2004. Ecologic analysis identified demographic factors associated with age-adjusted county-specific NHL incidence. NHL incidence in Pennsylvania increased annually: 1.6% and 2.5% in white and black men and 1.6% and 3.2% in white and black women. National trends were similar, except for smaller increases in white men. Diffuse lymphoma appeared to be the major contributor to the increases. NHL incidence was higher in Pennsylvania counties with greater percentages of urban residents. NHL incidence patterns in Pennsylvania were parallel to those seen nationally, with the highest rates occurring in white men and in persons residing in urban areas.

Generational risks for cancers not related to tobacco, screening, or treatment in the United States

BACKGROUND

To assess trends in cancer, the authors evaluated the risk of 1 generation compared with that 25 years earlier (generational risk) for 3 groupings of cancers: those related to tobacco; those that reflect advances in screening or treatment; and a residual category of all other cancers.

METHODS

In individuals ages 20 years to 84 years, age-period-cohort models were used to summarize time trends in terms of generational risk and average annual percentage change for US cancer incidence (1975-2004) and mortality (1970-2004) rates associated with these 3 cancer groupings.

RESULTS

Adult white men today developed 16% fewer tobacco-related cancers and had 21% fewer deaths because of those cancers than their fathers' generation, whereas adult white women experienced increases of 28% and 19%, respectively, relative to their mothers. The incidence of commonly screened cancers rose 74% in men and 10% in women, whereas mortality fell 25% in men and 31% in women. For cancers that have not been linked chiefly to tobacco or screening, the incidence was 34% and 23% higher in white men and white women, respectively, than in their parents' generation 25 years earlier. Mortality in this residual category decreased 14% in men and 18% in women. Results among blacks were qualitatively similar to those among whites.

CONCLUSIONS

Despite declining overall cancer death rates, adults are experiencing increased incidence of cancers that are not associated with tobacco or screening relative to their parents. Future research should examine whether similar patterns are exhibited in other modern nations and should identify population-wide avoidable risks that could account for unexplained increases in these residual cancers.

Lifestyle-related factors and environmental agents causing cancer: an overview

The increasing incidence of a variety of cancers after the Second World War confronts scientists with the question of their origin. In Western countries, expansion and ageing of the population as well as progress in cancer detection using new diagnostic and screening tests cannot fully account for the observed growing incidence of cancer. Our hypothesis is that environmental factors play a more important role in cancer genesis than it is usually agreed. (1) Over the last 2-3 decades, alcohol consumption and tobacco smoking in men have significantly decreased in Western Europe and North America. (2) Obesity is increasing in many countries, but the growing incidence of cancer also concerns cancers not related to obesity nor to other known lifestyle-related factors. (3) There is evidence that the environment has changed over the time period preceding the recent rise in cancer incidence, and that this change, still continuing, included the accumulation of many new carcinogenic factors in the environment. (4) Genetic susceptibility to cancer due to genetic polymorphism cannot have changed over one generation and actually favours the role of exogenous factors through gene-environment interactions. (5) Age is not the unique factor to be considered since the rising incidence of cancers is seen across all age categories, including children, and adolescents. (6) The fetus is specifically vulnerable to exogenous factors. A fetal exposure during a critical time window may explain why current epidemiological studies may still be negative in adults. We therefore propose that the involuntary exposure to many carcinogens in the environment, including microorganisms (viruses, bacteria and parasites), radiations (radioactivity, UV and pulsed electromagnetic fields) and many xenochemicals, may account for the recent growing incidence of cancer and therefore that the risk attributable to environmental carcinogen may be far higher than it is usually agreed. Of major concern are: outdoor air pollution by carbon particles associated with polycyclic aromatic hydrocarbons; indoor air pollution by environmental tobacco smoke, formaldehyde and volatile organic compounds such as benzene and 1,3 butadiene, which may particularly affect children and food contamination by food additives and by carcinogenic contaminants such as nitrates, pesticides, dioxins and other organochlorines. In addition, carcinogenic metals and metalloids, pharmaceutical medicines and some ingredients and contaminants in cosmetics may be involved. Although the risk fraction attributable to environmental factors is still unknown, this long list of carcinogenic and especially mutagenic factors supports our working hypothesis according to which numerous cancers may in fact be caused by the recent modification of our environment.

The forest for the trees: a systems approach to human health research

We explore the relationship between current research directions in human health and environmental and public health policy. Specifically, we suggest there is a link between the continuing emphasis in biomedical research on individualized, therapeutic solutions to human disease and the increased reliance on individual choice in response to environmental and/or public health threats. We suggest that continued research emphasis on these traditional approaches to the exclusion of other approaches will impede the discovery of important breakthroughs in human health research necessary to understand the emerging diseases of today. We recommend redirecting research programs to interdisciplinary and population-focused research that would support a systems approach to fully identifying the environmental factors that contribute to disease burden. Such an approach would be able to address the interactions between the social, ecological, and physical aspects of our environment and explicitly include these in the evaluation and management of health risks from environmental exposures.

The need to develop centers for environmental oncology

The scale and scope of the cancer problem in the United States today is much greater than four decades ago when the formal war against the disease was first announced. Patterns of the disease are not fully explained by known risk factors. Much progress has been made in understanding the molecular basis of carcinogenesis, particularly the near consensus (realization) that virtually all cancers arise from an accumulation of genetic mutations and the more recent recognition of the role of inflammation and the tissue microenvironment, in particular for hormone-dependent cancers. However, most genetic mutations that contribute to cancer are not inherited, and thus must be attributable to accumulation of somatic mutations and epigenetic changes, from as yet poorly understood environmental factors, that certainly cannot be explained entirely by tobacco, use and arise over the course of a lifetime. Much of the national effort to control cancer has focused on detecting and treating the disease--not on seeking approaches to prevent cases from arising. Given this reality, we present a cross-disciplinary framework for establishing comprehensive research and policy centers focused on environmental oncology to be based at selected academic cancer centers across the country. The principal goal of such centers is to improve the ability to prevent cancer, by developing effective interventions based on insights obtained from epidemiology, including molecular epidemiology and basic scientific research on genomic, metabolomic, and other biomarkers of exposure, susceptibility, and disease. As the needed scientific evidence for environmental factors contributing to cancer is revealed, these academic centers will develop specific interventions and/or policy recommendations regarding ways to lower the burden of cancer, based on existing information about cancer hazards in the personal, occupational, and general environment. Ultimately the centers will improve the ability to identify and control the underlying causes of the occurrence of cancer and its progression.

The crisis in U.S. and international cancer policy

The incidence of cancer in the United States and other major industrialized nations has escalated to epidemic proportions over recent decades, and greater increases are expected. While smoking is the single largest cause of cancer, the incidence of childhood cancers and a wide range of predominantly non-smoking-related cancers in men and women has increased greatly. This modern epidemic does not reflect lack of resources of the U.S. cancer establishment, the National Cancer Institute and American Cancer Society; the NCI budget has increased 20-fold since passage of the 1971 National Cancer Act, while funding for research and public information on primary prevention remains minimal. The cancer establishment bears major responsibility for the cancer epidemic, due to its overwhelming fixation on damage control--screening, diagnosis, treatment, and related molecular research--and indifference to preventing a wide range of avoidable causes of cancer, other than faulty lifestyle, particularly smoking. This mindset is based on a discredited 1981 report by a prominent pro-industry epidemiologist, guesstimating that environmental and occupational exposures were responsible for only 5 percent of cancer mortality, even though a prior chemical industry report admitted that 20 percent was occupational in origin. This report still dominates public policy, despite overwhelming contrary scientific evidence on avoidable causes of cancer from involuntary exposures to a wide range of environmental carcinogens. Since 1998, the ACS has been planning to gain control of national cancer policy, now under federal authority. These plans, developed behind closed doors and under conditions of nontransparency, with recent well-intentioned but mistaken bipartisan Congressional support, pose a major and poorly reversible threat to cancer prevention and to winning the losing war against cancer.

An epidemiologic study of hepatocellular carcinoma in Canada

BACKGROUND AND METHODS

To provide information on poorly described Canadian hepatocellular cancer epidemiology, we analyzed incident cases abstracted from the Canadian Cancer Registration Database (1969-1997) and Canadian annual death data (1969-1998). Age, sex, geographic distribution, and secular trends were described. Projection models were developed for the next decade.

RESULTS

Results indicated much higher incidence and mortality rates in males than females, with substantial increases for both with age. Age-standardized incidence rates increased an average of 3.4% per year in males, 1.2% per year in females (1969-1997). Age-standardized mortality rates increased an average of 1.48% in males, but decreased an average of 0.46% per year in females (1969-1998). Join-point analysis of the linear trends in the age-standardized incidence and mortality rates suggested that a new trend started to emerge about 1991. The fitted non-linear multiplicative model predicted the occurrence of 1,565 new cases and 802 deaths in the year 2010. HCC incidence was the highest in British Colombia, followed by Quebec, and the lowest in the Atlantic region.

CONCLUSIONS

Incidence rates of hepatocellular carcinoma have increased substantially, consistent with the reported increase in the prevalence of Hepatitis C Virus (HCV) and Hepatitis B Virus (HBV) infections in recent decades.

Radioimmunotherapy with yttrium-90 ibritumomab tiuxetan for patients with relapsed CD20+ B-cell non-Hodgkin's lymphoma

The clinical development and US Food and Drug Administration approval in 1997 of the monoclonal anti-CD20 antibody rituximab have been major treatment advances for patients with B-cell non-Hodgkin's lymphoma (NHL). Rituximab produces responses in approximately 50% of cases of relapsed, low grade NHL. Most of these responses are partial remissions; cure remains elusive. One way to enhance the effectiveness of monoclonal antibodies is to chelate radionuclides such as yttrium-90 ((90)Y) to the antibody. ( 90)Y is a high-energy, beta-emitting radioisotope that delivers most of its radiation over a path length of 2 to 5 mm. Therefore, the antibody delivers, or targets, the radiation only to CD20+ cells, sparing normal cells from the radiation. Ibritumomab is the murine anti-CD20 antibody that was engineered to develop the human chimeric antibody rituximab. Tiuxetan is a linker/chelator that is attached to the antibody to form ibritumomab tiuxetan (Zevalin; IDEC Pharmaceuticals, San Diego, CA). Zevalin can be reacted with (111)indium ((111)In) for imaging and (90)Y for therapy. Phase I studies of Zevalin have determined that patients with a baseline platelet count greater than 150,000 10(6)/L receive 0.4 mCi/kg. Patients with a platelet count of 100 to 149,000 10(6)/L should receive 0.3 mCi/kg. Zevalin has a higher overall response rate (ORR) than its cold antibody counterpart rituximab, as demonstrated in two separate clinical trials. The first trial (IDEC 106-04) randomized 143 rituximab-naïve patients with relapsed NHL to receive rituximab or Zevalin. The ORR for Zevalin was 80% compared with 56% for rituximab (P = 0.002). The second trial (IDEC 106-06) tested the efficacy of Zevalin in patients who were rituxan-refractory; the ORR was 74%. The main toxicity of Zevalin was reversible myelosuppression. These studies indicate that radiolabeled anti-CD20 antibodies can produce a higher ORR than rituximab. Single-dose Zevalin is another treatment alternative for patients with relapsed low grade NHL. It is well-tolerated even by older adults. The exact role of Zevalin in the therapy of NHL is undetermined. New studies are underway to explore whether patients can safely receive a second dose of Zevalin and to combine Zevalin with high-dose chemotherapy and stem cell rescue. The outcome of these studies will be helpful in deciding how best to integrate this new modality into the treatment paradigm of NHL.

Detection of DNA adducts in developing CD4+ CD8+ thymocytes and splenocytes following in utero exposure to benzo[a]pyrene

Environmental carcinogen exposure may play an important role in the incidence of cancer in children. In addition to environmental pollutants, maternal smoking during pregnancy may be a contributing factor. Major carcinogenic components of cigarette smoke and other combustion by-products in the environment include polycyclic aromatic hydrocarbons (PAH). Mouse offspring exposed during midpregnancy to the PAH, benzo[a]pyrene (B[a]P), show significant deficiencies in their immune functions, observed in late gestation which persist for at least 18 months. Tumor incidences in these progeny are 8 to 10-fold higher than in controls. We have demonstrated a significant reduction in thymocytes (CD4+ CD8+, CD4+ CD8+ Vbeta8+, CD4+ CD8+ Vgamma2+) from newborn and splenocytes (CD4+ CD8+) from 1-week-old mouse progeny exposed to B[a]P in utero. To investigate possible causes of the observed T cell reduction, we analyzed the thymocytes and splenocytes from progeny and maternal tissues for the presence of B[a]P-DNA adducts. Adducts were detected in maternal, placental and offspring lymphoid tissues at day 19 of gestation, at birth and 1-wk after birth. The presence of B[a]P-DNA adducts in immature T cells may, in part, explain the previously observed T cell immunosuppression and tumor susceptibility in mice exposed to B[a]P in utero. The effects of DNA lesions on progeny T cells may include interference with normal T-cell development. These results provide a possible explanation for the relationship between maternal smoking during pregnancy and childhood carcinogenesis.

Current therapeutic approaches in the treatment of Non-Hodgkin's lymphoma

OBJECTIVES

To review the causes, classification, treatment, and new treatment modalities of non-Hodgkin's lymphoma.

DATA SOURCES

Published literature and experimental therapies.

CONCLUSIONS

The increasing incidence of non-Hodgkin's lymphoma can be attributed to a growth in the number of immunodeficiency and autoimmune disorders, infectious agents, and human T-cell leukemia-lymphoma virus. Treatment options include watch-and-wait, radiation, chemotherapy, biologic therapy, and stem cell/bone marrow transplant. New therapies include the use of monoclonal antibodies and radioimmunotherapy. Experimental therapies include high-dose radioimmunotherapy and stem cell transplantation, vaccines, and antisense antiangiogensis agents.

IMPLICATIONS FOR NURSING PRACTICE

Nurses will need to become versed in this modality, and will play an important part not only in therapy but also in patient education.

Breast cancer and NSAID use: a meta-analysis

Recent epidemiological studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of several cancers including breast cancer. This meta-analysis examined the studies on NSAID use and breast cancer. The estimators of relative risk and associated variances, which have been adjusted for the greatest number of confounders, were abstracted and included in the meta-analysis. Combined estimators of relative risk (RR) were calculated using either fixed or random effect models. Meta-analyses were performed on 6 cohort studies (number of cases ranged from 14 to 2414) and 8 case-control studies (number of cases ranged from 252 to 5882). The combined estimate of relative risk was 0.82 (95% confidence interval [CI] = 0.75-0.89). The combined estimate for cohort studies was 0.78 (95% CI = 0.62-0.99) and was 0.87 (95% CI = 0.84-0.91) for case-control studies. The findings of this meta-analysis suggest that NSAID use may be associated with a small decrease in the risk of breast cancer. However, the available data are insufficient to estimate the dose-response effect for duration and frequency of use of any particular types of NSAID.