Cancer mortality rates fall: a turning point for the nation

Prostate cancer

In developed countries, prostate cancer is the second most frequently diagnosed cancer, and the third most common cause of death from cancer in men. Apart from age and ethnic origin, a positive family history is probably the strongest known risk factor. Clinically, prostate cancer is diagnosed as local or advanced, and treatments range from surveillance to radical local treatment or androgen-deprivation treatment. Androgen deprivation reduces symptoms in about 70-80% of patients with advanced prostate cancer, but most tumours relapse within 2 years to an incurable androgen-independent state. The recorded incidence of prostate cancer has substantially increased in the past two decades, probably because of the introduction of screening with prostate-specific antigen, the use of improved biopsy techniques for diagnosis, and increased public awareness. Trends in mortality from the disease are less clearcut. Mortality changes are not of the same magnitude as the changes in incidence, and in some countries mortality has been stable or even decreased. The disparity between reported incidence and mortality rates leads to the probable conclusion that only a small proportion of diagnosed low-risk prostate cancers will progress to life-threatening disease during the lifetime of the patient.

Screening for prostate cancer: an update

OBJECTIVES

To review evidence regarding the potential introduction of prostate cancer screening programmes and highlight issues pertinent to the management of screen-detected prostate cancer.

METHODS

Screening for prostate cancer is a controversial health care issue in general and urological practice. A PubMed database search was performed, followed by a systematic review of the literature, to examine the evidence base underlying prostate cancer screening.

RESULTS

A prostate cancer screening programme should satisfy several key postulates prior to its introduction. To date, several of these postulates have not been satisfied, and the evidence available for prostate cancer screening is currently insufficient to warrant its introduction as a public health policy. The natural history of screen-detected prostate cancer remains poorly understood, and recent evidence suggests that a screening programme may detect a large number of men with indolent disease who may be subsequently overtreated. Several randomised clinical trials are currently in progress and it is hoped that they will provide robust evidence to inform future practice.

CONCLUSIONS

National systematic prostate cancer screening programmes outside randomised clinical trial settings have not been implemented to date owing to lack of robust evidence that such programmes would improve survival and/or quality of life in men with screen-detected disease. Forthcoming results of clinical trials and the application of appropriate risk stratification to prevent overtreatment of indolent prostate cancer are likely to change practice in coming years.

Prostate cancer: epidemiology and risk factors

After years of rapid increase, the incidence of prostate cancer has begun to decline in certain areas in the USA. Although these temporal trends are consistent with the impact of screening, it still remains to be shown that early detection programmes and screening will result in a reduced mortality rate from this disease. A positive family history of prostate cancer has been established as an important risk factor, and recent research supports and points to the existence of a subgroup of prostate cancer families with a hereditary form of the disease. Diet is another well-known risk factor. Recently, it has become evident that nutritional factors might both prevent the progression of prostate cancer or induce it.

Decline in the overall incidence of regional-distant prostate cancer in Olmsted County, MN, 1980-2000

OBJECTIVE

To describe trends in the incidence of regional-distant prostate cancer over the entire course of the disease, before and after the introduction of prostate-specific antigen screening in 1987.

PATIENTS AND METHODS

All residents of Olmsted County, MN, USA, with a diagnosis of prostate cancer from 1964 to 2000 were identified using the resources of the Rochester Epidemiology Project. Their community medical records were examined to identify men with documented evidence of locally advanced (T3/4 or N+ disease) or metastatic prostate cancer between 1980 and 2000.

RESULTS

In all, 407 men had regional-distant prostate cancer, based on clinical or pathological staging at the time of initial diagnosis of prostate cancer and/or on radiological information over the entire course of their illness. The age-adjusted incidence per 100,000 men increased from 47.4 in 1980-86 to 65.8 in 1987-93, and declined to 33.3 in 1994-2000 (P < 0.001). Based on clinical and radiological information over the entire course of illness (268 men) the age-adjusted incidence of regional-distant disease was 42.3 in 1980-86, 41.2 in 1987-93, and declined to 18.1 in 1994-2000 (P < 0.001). These latter rates were 27%, 32% and 47% higher for the three periods, respectively, than rates based on clinical staging at initial diagnosis of prostate cancer.

CONCLUSIONS

The overall incidence of regional-distant stages of prostate cancer has declined in recent years, regardless of the stage at initial diagnosis. This may be a result in part of early detection and curative treatments. These findings also indicate that assessing the incidence of regional-distant prostate cancer only at the initial diagnosis underestimates the full impact of the benefits of early detection and treatment.

Secular trends in cancer mortality, California 1970-1998

BACKGROUND

Monitoring mortality is a meaningful way to evaluate the effectiveness of cancer control activities. Results of trend analysis for cancer related deaths by race/ethnicity in California from 1970 to 1998 are reported here.

METHODS

Age-adjusted cancer mortality rates in California were used in the analysis of secular trends. Mortality patterns for selected cancers in all races combined are compared with similar patterns in the US for 1973-1998.

RESULTS

The overall cancer mortality rates in California began to decline in 1987 in both men and women. Although mortality trends by site, sex, and race/ethnicity showed significant variations, the overall pattern in California is heavily influenced by trends for the non-Hispanic white (NHW) population and is very similar to the patterns in the US with minor differences in the magnitude and trend.

CONCLUSIONS

This is the first time that secular trends in cancer mortality for California are presented by race and ethnicity. Despite notable racial differences, the overall trend follows a declining pattern. Detailed explanation of the reasons behind the observed patterns is not included in this report. Some of the differences between California and the US, however, can be explained by differences in the racial and ethnic composition of the two populations. Approximately 45% of the California population has Hispanic (HSP) or Asian origins among whom cancer mortality rates are substantially lower. Another factor is the difference in the intensity and coverage of cancer related activities such as tobacco control. Prevalence of smoking in California is much lower than the rest of the US.

Screening decreases prostate cancer mortality: 11-year follow-up of the 1988 Quebec prospective randomized controlled trial

PURPOSE

This clinical trial is aimed at evaluating the impact of prostate cancer screening on cancer-specific mortality.

SUBJECTS AND METHODS

Forty-six thousand four hundred and eighty-six (46,486) men aged 45-80 years registered in the electoral roll of the Quebec city area were randomized in 1988 between screening and no screening. Screening included measurement of serum prostatic specific antigen (PSA) using 3.0 ng/ml as upper limit of normal and digital rectal examination (DRE) at first visit. At follow-up visits, serum PSA only was used.

RESULTS

Seventy-four (74) deaths from prostate cancer occurred in the 14,231 unscreened controls while 10 deaths were observed in the screened group of 7,348 men during the first 11 years following randomization. Median follow-up of screened men was 7.93 years. A Cox proportional hazards model of the age at death from prostate cancer shows a 62% reduction (P < 0.002, Fisher's exact test) of cause-specific mortality in the screened men (P = 0.005). These results are in agreement with the continuous decrease of prostate cancer mortality observed in North America.

Screening for prostate cancer

Epidemiologically, screening is justified by the importance of the disease and the lack of prospects for primary prevention, but evidence from natural history is unhelpful since men are more likely to die with, rather than from, prostate cancer. The available screening tests do not always detect men whose lesions could result in future morbidity or mortality. Evidence is limited for the benefits of treatment for localised cancers detected through screening, whereas the evidence for harm is clear. Observational evidence for the effect of population screening programmes is mixed, with no clear association between intensity of screening and reduced prostate cancer mortality. Screening for prostate cancer cannot be justified in low-risk populations, but the balance of benefit and harm will be more favourable after risk stratification. Prostate cancer screening can be justified only in research programmes designed to assess its effectiveness and help identify the groups who may benefit.

Palliative medicine and medical oncology

Traditionally, medical oncology and palliative care have been considered two distinct and separate disciplines, both as regards treatment objectives and delivery times. Palliative care in terminal stages, aimed exclusively at evaluating and improving quality of life, followed antitumor therapies, which concentrated solely on quantitative results (cure, prolongation of life, tumoral mass shrinkage). Over the years, more modern concepts have developed on the subject. Medical oncology, dealing with the skills and strategic co-ordination of oncologic interventions from primary prevention to terminal phases, should also include assessment and treatment of patients' subjective needs. Anticancer therapies should be evaluated in terms of both the quantitative and qualititative impact on patients' lives. Hence, the traditional view of palliative care has to be modified: it constitutes a philosophical and methodological approach to be adopted from the early phases of illness. It is not the evident cultural necessity of integrating medical oncology with palliative medicine that may be a matter of argument, but rather the organizational models needed to put this combined care into practice: should continuous care be guaranteed by a single figure, the medical oncologist, or rather by an interdisciplinary providers' team, including full-time doctors well-equipped for palliative care? In this paper the needs of cancer patients and the part that a complete oncologist should play to deal with such difficult and far-reaching problems are firstly described. Then, as mild provocation, data and critical considerations on the ever increasing needs of palliative care, the present shortcomings in quality of life and pain assessment and management by medical oncologists, and the uncertain efficacy of interventional programmes to change clinical practice are described. Finally, a model of therapeutic continuity is presented. which in our view is realistic and feasible: an Oncologic Programme as the unifying process, and the Comprehensive Cancer Centre, or the Oncologic Department, the delivering structure.

Lung cancer screening: improved survival but no reduction in deaths--the role of "overdiagnosis"

BACKGROUND

Randomized controlled trials (RCTs) of lung cancer screening consistently show an excess number of cancer cases and longer survival in screened groups, but no difference in mortality between screened and control populations.

METHODS

The current study reviewed the various types of biases that confuse comparisons based on intermediate endpoints such as stage distribution and survival and the reasons for basing evaluations in RCTs of screening for early cancers on mortality from a specific cancer.

RESULTS

Four RCTs all showed improved stage of disease and survival in screened subjects, but there was no difference in mortality between screened and unscreened populations. The possible explanations for the higher incidence are chance (failed randomization) or "overdiagnosis" (detection of cases by screening that otherwise would never have surfaced). Analysis of the trial results confirmed that chance alone was a very unlikely explanation. Evidence suggests that some overdiagnosis of lung cancer is likely in screened subjects. This is a consistent observation in all other programs of screening for early cancers (breast, prostate, and neuroblastoma).

CONCLUSIONS

Overdiagnosis of cancer cases resulting from the screening process itself will give rise to excess cases of disease, and may, at least in part, explain the observations in the randomized trials.

Evaluation of prostatic specific antigen and digital rectal examination as screening tests for prostate cancer

BACKGROUND

The 11,811 first visits and 46,751 annual follow-up visits performed since 1988 were analyzed in order to assess the efficacy of serum prostatic specific antigen (PSA) and digital rectal examination (DRE) for diagnosis of prostate cancer.

METHODS

At first visit, screening included DRE and measurement of PSA using 3.0 ng/ml as upper limit of normal, demonstrated as optimal value in the course of the study. Transrectal echography of the prostate (TRUS) was performed only if PSA and/or DRE was abnormal. For elevated PSA, biopsy was performed only if PSA was above the value predicted from prostatic volume measured by TRUS. At follow-up visits, it was decided during the course of the study to use PSA alone.

RESULTS

PSA was above 3.0 ng/ml in 16.6% and 15.6% of men at first and follow-up visits, respectively. Prostate cancer was found in 2.9% of men invited for screening at first visit and in only 0.4% of men at follow-up visits for a 7.1-fold decrease at follow-up visits done up to 11 years. PSA alone allowed to find 90.5% and 90. 0% of cancers at first and follow-up visits, respectively, compared to 41.1% and 25.0% by DRE alone. In the presence of normal PSA, 344 and 1,919 DREs are needed to find one prostate cancer at first and follow-up visits, respectively. A significant improvement in stage of the disease is found at follow-up (215 cancers) compared to first visits (337 cancers). Comparison made between men invited for screening and those who were not invited but screened showed no significant difference in terms of incidence and prevalence of prostate cancer as well as diagnosis of cancer as a function of age or as a function of PSA, DRE, and TRUS data. The cost for finding one case of prostate cancer is estimated at Can $2,420 and Can $7, 105 (first and follow-up visits, respectively, when PSA is used as prescreening).

CONCLUSIONS

PSA used as prescreening and followed by DRE and TRUS when PSA is abnormal is highly efficient in detecting prostate cancer at a localized (potentially curable) stage since 99% of the cancers diagnosed were at such a localized stage, thus practically eliminating the diagnosis of metastatic and noncurable prostate cancer. The approach used is highly reliable, sensitive, efficient, and acceptable by the general population. The detection of clinically nonsignificant cancer is an exception.

The annual report to the nation on the status of cancer, 1973-1997, with a special section on colorectal cancer

BACKGROUND

This annual report to the nation addresses progress in cancer prevention and control in the U.S. with a special section on colorectal cancer. This report is the joint effort of the American Cancer Society, the National Cancer Institute (NCI), the North American Association of Central Cancer Registries (NAACCR), and the Centers for Disease Control and Prevention (CDC), including the National Center for Health Statistics (NCHS).

METHODS

Age-adjusted rates were based on cancer incidence data from the NCI and NAACCR and underlying cause of death as compiled by NCHS. Joinpoint analysis was based on NCI Surveillance, Epidemiology, and End Results (SEER) program incidence rates and NCHS death rates for 1973-1997. The prevalence of screening examinations for colorectal cancer was obtained from the CDC's Behavioral Risk Factor Surveillance System and the NCHS's National Health Interview Survey.

RESULTS

Between 1990-1997, overall cancer incidence and death rates declined. Joinpoint analyses of cancer incidence and death rates confirmed the declines described in earlier reports. The incidence trends for colorectal cancer have shown recent steep declines for whites in contrast to a leveling off of the rates for blacks. State-to-state variations occurred in colorectal cancer screening prevalence as well as incidence and death rates.

CONCLUSIONS

The continuing declines in overall cancer incidence and death rates are encouraging. However, a few of the top ten incidence or mortality cancer sites continued to increase or remained level. For many cancer sites, whites had lower incidence and mortality rates than blacks but higher rates than Hispanics, Asian and Pacific Islanders, and American Indians/Alaska Natives. The variations in colorectal cancer incidence and death rates by race/ethnicity, gender, age, and geographic area may be related to differences in risk factors, demographic characteristics, screening, and medical practice. New efforts currently are underway to increase awareness of screening benefits and treatment for colorectal cancer.

The annual report to the nation on the status of cancer, 1973-1997, with a special section on colorectal cancer

BACKGROUND

This annual report to the nation addresses progress in cancer prevention and control in the U.S. with a special section on colorectal cancer. This report is the joint effort of the American Cancer Society, the National Cancer Institute (NCI), the North American Association of Central Cancer Registries (NAACCR), and the Centers for Disease Control and Prevention (CDC), including the National Center for Health Statistics (NCHS).

METHODS

Age-adjusted rates were based on cancer incidence data from the NCI and NAACCR and underlying cause of death as compiled by NCHS. Joinpoint analysis was based on NCI Surveillance, Epidemiology, and End Results (SEER) program incidence rates and NCHS death rates for 1973-1997. The prevalence of screening examinations for colorectal cancer was obtained from the CDC's Behavioral Risk Factor Surveillance System and the NCHS's National Health Interview Survey.

RESULTS

Between 1990-1997, overall cancer incidence and death rates declined. Joinpoint analyses of cancer incidence and death rates confirmed the declines described in earlier reports. The incidence trends for colorectal cancer have shown recent steep declines for whites in contrast to a leveling off of the rates for blacks. State-to-state variations occurred in colorectal cancer screening prevalence as well as incidence and death rates.

CONCLUSIONS

The continuing declines in overall cancer incidence and death rates are encouraging. However, a few of the top ten incidence or mortality cancer sites continued to increase or remained level. For many cancer sites, whites had lower incidence and mortality rates than blacks but higher rates than Hispanics, Asian and Pacific Islanders, and American Indians/Alaska Natives. The variations in colorectal cancer incidence and death rates by race/ethnicity, gender, age, and geographic area may be related to differences in risk factors, demographic characteristics, screening, and medical practice. New efforts currently are underway to increase awareness of screening benefits and treatment for colorectal cancer.

Screening and early hormonal treatment of prostate cancer are accumulating strong evidence and support

BACKGROUND

I review the data published during the last 5 years on the effects of early treatment of prostate cancer on survival.

METHODS

Data from prospective and randomized studies as well as from population-based studies are presented.

RESULTS

Two studies (European Organization for Research and Treatment of Cancer and Radiation Therapy Oncology Group) in stage T3 disease have shown that long-term (3 years or indefinite, respectively) androgen blockade prolongs life in patients receiving androgen blockade in addition to radiotherapy compared to radiotherapy alone. In the UK Medical Research Council study, androgen blockade at diagnosis of locally advanced or asymptomatic patients decreased cancer-specific death by 21% compared to delayed treatment. A 69% decrease in prostate cancer death was observed in the Quebec Randomized Prostate Cancer Screening Study. Population-based studies in Sweden and Denmark have shown that 62% and 63%, respectively, of patients diagnosed with localized prostate cancer will die from the disease if not treated immediately. Decreases in prostate cancer death rate of 6.3-23% have been found between 1991-1997 in the US and Canada, respectively.

CONCLUSIONS

Treatment of localized disease has been shown in all the available randomized studies to cause a marked decrease in prostate cancer death. Simple use of the available screening procedures and treatments for localized prostate cancer could cause a dramatic decrease in prostate cancer death.

Annual report to the nation on the status of cancer, 1973-1996, with a special section on lung cancer and tobacco smoking

BACKGROUND

The American Cancer Society, the National Cancer Institute (NCI), and the Centers for Disease Control and Prevention (CDC), including the National Center for Health Statistics (NCHS), provide the second annual report to the nation on progress in cancer prevention and control, with a special section on lung cancer and tobacco smoking.

METHODS

Age-adjusted rates (using the 1970 U.S. standard population) were based on cancer incidence data from NCI and underlying cause of death data compiled by NCHS. The prevalence of tobacco use was derived from CDC surveys. Reported P values are two-sided.

RESULTS

From 1990 through 1996, cancer incidence (-0.9% per year; P = .16) and cancer death (-0.6% per year; P = .001) rates for all sites combined decreased. Among the 10 leading cancer incidence sites, statistically significant decreases in incidence rates were seen in males for leukemia and cancers of the lung, colon/rectum, urinary bladder, and oral cavity and pharynx. Except for lung cancer, incidence rates for these cancers also declined in females. Among the 10 leading cancer mortality sites, statistically significant decreases in cancer death rates were seen for cancers of the male lung, female breast, the prostate, male pancreas, and male brain and, for both sexes, cancers of the colon/rectum and stomach. Age-specific analyses of lung cancer revealed that rates in males first declined at younger ages and then for each older age group successively over time; rates in females appeared to be in the early stages of following the same pattern, with rates decreasing for women aged 40-59 years.

CONCLUSIONS

The declines in cancer incidence and death rates, particularly for lung cancer, are encouraging. However, unless recent upward trends in smoking among adolescents can be reversed, the lung cancer rates that are currently declining in the United States may rise again.

Screening for prostate cancer: the roles of science, policy, and opinion in determining what is best for patients

Controversy over screening for prostate cancer involves both scientific and policy considerations. The principal scientific questions are whether tumors detected by screening are clinically significant, whether screening generates too many false-positive results, and whether early detection lowers morbidity or mortality. Both screening and treatment of prostate cancer can be harmful, making the tradeoff between benefits and risks especially relevant. Studies suggest that this judgment is highly personal, depending on the relative importance that individuals assign to potential outcomes. Opinions and policy considerations also influence views about the appropriateness of screening. Chief among these are personal beliefs about benefits and harms, medicolegal concerns, patient expectations, resource constraints, and opportunity costs. Appropriate policy must discriminate between what is best for populations and for individual patients. The lack of evidence of benefit and the potential harms argue against a societal policy of routine screening. Individual patients who could benefit from screening should be informed about the potential benefits and harms and invited to make a personal choice based on their priorities and concerns.

Screening decreases prostate cancer death: first analysis of the 1988 Quebec prospective randomized controlled trial

BACKGROUND

The 46,193 men aged 45 to 80 years registered in the electoral roll of Quebec City and its Metropolitan area were randomized in November 1988 between screening and no screening in a study aimed of assessing the impact of prostate cancer screening on cause-specific death.

METHODS

At first visit, screening included measurement of serum prostatic specific antigen (PSA) using 3.0 ng/ml as upper limit of normal and a digital rectal examination (DRE). Transrectal echography of the prostate (TRUS) was performed only if PSA and/or DRE was abnormal and biopsy was then done, only if PSA was above the predicted PSA value. At follow-up visits, PSA alone was used as prescreening.

RESULTS

137 deaths due to prostate cancer occurred between 1989 and 1996, inclusively, in the 38,056 unscreened men while only 5 deaths were observed among the 8,137 screened individuals. The prostate cancer death rates during the eight-year period were 48.7 and 15 per 100,000 man-years in the unscreened and screened groups, respectively, for a 3.25 odds ratio in favor of screening and early treatment (P < 0.01).

CONCLUSIONS

If PSA screening is started at the age of 50 years (or 45 years in the higher risk population), annual or biannual PSA alone is highly efficient to identify the men who are at high risk of having prostate cancer. Coupled with treatment of localized disease, this approach demonstrates, for the first time, that early diagnosis and treatment permits a dramatic decrease in deaths from prostate cancer.

Striking increase in incidence of prostate cancer in men aged < 60 years without improvement in prognosis

Increased awareness and improved diagnostic techniques have led to earlier diagnosis of prostate cancer and increased detection of subclinical cases, resulting in improved prognosis. We postulated that the considerable increase in incidence under age 60 is not attributable only to increased detection. To test this hypothesis, we studied incidence, mortality and relative survival among middle-aged patients diagnosed in south-east Netherlands and East Anglia (UK) between 1971 and 1994. Prostate-specific antigen (PSA) testing did not occur before 1990. Between 1971 and 1989, the age-standardized incidence at ages 40-59 increased from 8.8 to 12.5 per 10(5) in The Netherlands and from 7.0 to 11.6 per 10(5) in East Anglia. Five-year relative survival did not improve in East Anglia and even declined in southeast Netherlands from 65% [95% confidence interval (CI) 47-83) in 1975-79 to 48% (CI 34-62) in 1985-89. Mortality due to prostate cancer among men aged 45-64 years increased by 50% in south-east Netherlands and by 61% in East Anglia between 1971 and 1989, but decreased slightly in the 1990s. Because other factors adversely influencing the prognosis are unlikely, our results indicate an increase in the incidence of fatal prostate cancer among younger men in the era preceding PSA testing.

The decline in U.S. cancer mortality from 1991 to 1995: what's behind the numbers?

In 1996, a series of articles and news stories about cancer mortality in the United States proclaimed a "turning point in the 25-year war on cancer." While these articles and stories pointed to a recent decline in overall cancer mortality, they missed some important points about increases in specific types. They also ignored the politics behind the emphasis on smoking and diet as the main contributors to the cancer rates and the racial disparities in the U.S. data. In addition, recent articles on the decline in cancer mortality fail to note the much sharper decline in heart disease mortality. Continued efforts to reduce carcinogenic exposures at work and in the environment are needed to truly reduce the cancer burden.

Colorectal cancer screening and follow-up

Cancer of the colon and rectum is a significant health problem in the United States. Nearly 50% of the 186,000 patients diagnosed annually with colorectal cancer will eventually die of their disease. Because development of a colorectal carcinoma is most frequently preceded by the development of a well-recognized pre-malignant lesion, screening modalities can significantly impact the incidence and mortality rate of this disease. Population screening employing digital rectal examination, fecal occult blood testing and endoscopic examination of the rectum and colon has been demonstrated to reduce the risk of death from colorectal cancer. Screening regimens should be instituted at an earlier age and with increased frequency for patients in the highest risk categories. Patients who have been treated for a cancer of the colon or rectum should undergo surveillance at regular intervals in an attempt to identify recurrences of disease both in the residual colon and rectum and at distant sites. Most physicians and patients believe that intensive follow-up strategies will afford improved survival and quality of life, however few randomized studies examining the utility of intensive follow-up programs have been performed and the quality of cancer-related follow-up literature is generally poor. Good-quality clinical trials are needed to sort out which tests make a difference in the patient's long-term outcome. The algorithm for surveillance for recurrence in the future may be altered as newer testing modalities are developed.

The prevention of cancer

1. The major causes of cancer are as follows: (a) Smoking: about a third of U.S. cancer (90% of lung cancer). (b) Dietary imbalances, e.g., lack of dietary fruits and vegetables: The quarter of the population eating the least fruits and vegetables has double the cancer rate for most types of cancer compared to the quarter eating the most; micronutrients may account for much of the protective effect of fruits and vegetables. Excess calories may also contribute to cancer. (c) Chronic infections: mostly in developing countries. (d) Hormonal factors influenced by life-style. 2. There is no epidemic of cancer, except for lung cancer due to smoking. Cancer mortality rates have declined 16% since 1950 (excluding lung cancer and adjusted for the increased life span of the population). 3. Regulatory policy that is focused on traces of synthetic chemicals is based on misconceptions about animal cancer tests. Recent research contradicts these ideas: (a) Rodent carcinogens are not rare. Half of all chemicals tested in standard high-dose animal cancer tests, whether occurring naturally or produced synthetically, are "carcinogens." (b) There are high-dose effects in these rodent cancer tests that are not relevant to low-dose human exposures and which can explain the high proportion of carcinogens. (c) Though 99.9% of the chemicals humans ingest are natural, the focus of regulatory policy is on synthetic chemicals. Over 1000 chemicals have been described in coffee: 27 have been tested and 19 are rodent carcinogens. Plants that we eat contain thousands of natural pesticides which protect plants from insects and other predators: 64 have been tested and 35 are rodent carcinogens. 4. There is no convincing evidence that synthetic chemical pollutants are important for human cancer. Regulations that try to eliminate minuscule levels of synthetic chemicals are enormously expensive: EPA estimates that total expenditures on environmental regulations cost $140 billion/year. It has been estimated by others that the United States spends 100 times more to prevent one hypothetical, highly uncertain death from a synthetic chemical than it spends to save a life by medical intervention. Attempting to reduce tiny hypothetical risks also has costs; for example, if reducing synthetic pesticides makes fruits and vegetables more expensive, thereby decreasing consumption, then cancer will be increased. 5. Improved health will come from knowledge due to biomedical research and from life-style changes by individuals. Little money is spent on biomedical research or on educating the public about lifestyle hazards, compared to the cost of regulations.

Cancer incidence and mortality, 1973-1995: a report card for the U.S

BACKGROUND

The American Cancer Society, the National Cancer Institute (NCI), and the Centers for Disease Control and Prevention including the National Center for Health Statistics (NCHS) agreed to produce together an annual "Report Card" to the nation on progress related to cancer prevention and control in the U.S.

METHODS

This report provides average annual percent changes in incidence and mortality during 1973-1990 and 1990-1995, plus age-adjusted cancer incidence and death rates for whites, blacks, Asians and Pacific Islanders, and Hispanics. Information on newly diagnosed cancer cases is based on data collected by NCI, and information on cancer deaths is based on underlying causes of death as reported to NCHS.

RESULTS

For all sites combined, cancer incidence rates decreased on average 0.7% per year during 1990-1995 (P > 0.05), in contrast to an increasing trend in earlier years. Among the ten leading cancer incidence sites, a similar reversal in trends was apparent for the cancers of the lung, prostate, colon/rectum, urinary bladder, and leukemia; female breast cancer incidence rates increased significantly during 1973-1990 but were level during 1990-1995. Cancer death rates for all sites combined decreased on average 0.5% per year during 1990-1995 (P < 0.05) after significantly increasing 0.4% per year during 1973-1990. Death rates for the four major cancers (lung, female breast, prostate, and colon/rectum) decreased significantly during 1990-1995.

CONCLUSIONS

These apparent successes are encouraging and signal the need to maximize cancer control efforts in the future so that even greater in-roads in reducing the cancer burden in the population are achieved.

Participation in colorectal cancer screening: a review

The purpose of this review is to evaluate the published literature on adherence to colorectal cancer (CRC) screening with fecal occult blood testing (FOBT) and sigmoidoscopy. Specifically, the review addresses the following: 1) prevalence of FOBT and sigmoidoscopy; 2) interventions to increase adherence to FOBT and sigmoidoscopy; 3) correlates or predictors of adherence to FOBT and sigmoidoscopy; and 4) reasons for nonadherence. Other objectives are to put the literature on CRC screening adherence in the context of recently reported findings from experimental interventions to change prevention and early detection behaviors and to suggest directions for future research on CRC screening adherence. CRC screening offers the potential both for primary and for secondary prevention. Data from the 1992 National Health Interview Survey show that 26% of the population more than 49 years of age report FOBT within the past 3 years and 33% report ever having had sigmoidoscopy. The Year 2000 goals set forth in Healthy People 2000 are for 50% of the population more than 49 years of age to report FOBT within the past 2 years and for 40% to report that they ever had sigmoidoscopy. Thus, systematic efforts to increase CRC screening are warranted. To date, attempts to promote CRC screening have used both a public health model that targets entire communities, e.g., mass media campaigns, and a medical model that targets individuals, e.g., general practice patients. Most of these efforts, however, did not include systematic evaluation of strategies to increase adherence. The data on FOBT show that the median adherence rate to programmatic offers of FOBT is between 40% and 50%, depending on the type of population offered the test, e.g., patients or employees. Approximately, 50% of those initially offered testing in unselected populations will respond to minimal prompts or interventions. A salient issue for FOBT, however, is whether or not the behavior can be sustained over time. Fewer studies examined adherence to sigmoidoscopy. Adherence was highest in relatives of CRC cases and in employer-sponsored programs offered to workers at increased risk of CRC. At present, we know very little about the determinants of CRC screening behaviors, particularly as they relate to rescreening.