Calcium channel blockers, cancer incidence, and cancer mortality in a cohort of U.S. women: the nurses' health study

BACKGROUND: Some studies have suggested that the use of calcium channel blockers may increase the risk of cancer. A possible association of the use of calcium channel blockers with cancer incidence and cancer mortality was addressed using data from the Nurses' Health Study. METHODS: In this study, a total of 18,635 female nurses reported regularly taking at least 1 of 4 cardiovascular medications in 1988: diuretics, beta-blockers, calcium channel blockers, and/or angiotensin-converting enzyme (ACE) inhibitors. Cancer incidence and cancer deaths were ascertained until 1994. RESULTS: During 6 years of follow-up, 852 women were newly diagnosed with cancer and 335 women died of cancer. Women who reported the use of calcium channel blockers had no increased risk of newly diagnosed cancer compared with those taking other cardiovascular drugs (relative risk=1.02; 95% CI 0.83-1.26). The relative risk of dying from cancer associated with the self-reported use of calcium channel blockers was 1.25 (95% CI 0.91-1.72). Relative risks were adjusted for the following self-reported factors: age; weight; height; cholesterol level; systolic and diastolic blood pressure; smoking; alcohol intake; physical activity; menopausal status; postmenopausal hormone use; aspirin use; and history of diabetes, cancer, stroke, myocardial infarction, coronary artery bypass graft or percutaneous transluminal coronary angioplasty, angina, and hypertension. Regarding site specific cancer incidence and mortality, only lung cancer incidence was somewhat increased (RR=1.61; 95% CI 0.88-2.96). CONCLUSIONS: These data suggest no important increase in overall cancer incidence or cancer mortality related to the self-reported use of calcium channel blockers.     

Risk of esophageal and gastric adenocarcinomas in relation to use of calcium channel blockers, asthma drugs, and other medications that promote gastroesophageal reflux

Incidence of adenocarcinomas of the esophagus and gastric cardia has risen dramatically over the past 2 decades in the U. S., for reasons that are not yet clear. A number of common medications (e.g., calcium channel blockers, tricyclic antidepressants, and certain asthma medications) promote gastroesophageal reflux by relaxing the lower esophageal sphincter (LES). Reflux is thought to increase cancer risk by promoting cellular proliferation, and by exposing the esophageal epithelium to potentially genotoxic gastric and intestinal contents. Recent studies have suggested that calcium channel blockers may also increase cancer risk by inhibiting apoptosis. Using personal interview data from a multicenter, population-based case-control study conducted between 1993 and 1995 in three areas of the U. S., we evaluated whether the use of LES-relaxing drugs was associated with increased risk of adenocarcinomas of the esophagus and gastric cardia. Cases of esophageal adenocarcinoma (n = 293) and gastric cardia adenocarcinoma (n = 261) were compared with general population controls (n = 695). Information on additional case groups of esophageal squamous cell carcinoma (n = 221) and noncardia gastric cancer (n = 368) were also available for comparison. Overall, 27.4% of controls had used one or more of these drugs for at least 6 months, compared with 30.2% of esophageal adenocarcinoma and 23.8% of gastric cardia adenocarcinoma cases. The adjusted odds ratios (ORs) for ever use were 1.0 [95% confidence interval (CI) = 0.7-1.5] and 0.8 (95% CI = 0.5-1.1), respectively. There was little evidence of increasing risk with increasing duration of use of all LES-relaxing drugs together. We found an increased risk of esophageal adenocarcinoma among persons reporting use of asthma drugs containing theophylline (OR = 2.5; 95% CI = 1.1-5.6) or beta agonists (OR = 1.7; 95% CI = 0.8-3.8). Risks were higher among long-term users (>5 years) of these drugs (OR = 3.1; 95% CI = 0.9-10.3 and OR = 2.3; 95% CI = 0.8-7.0, respectively). In contrast, there was no evidence that the use of calcium channel blockers or other specific groups of drugs increased the risk of any of the cancers studied. These results provide reassuring evidence that the increases in incidence of adenocarcinomas of the esophagus and gastric cardia are not likely to be related to the use of LES-relaxing drugs as a group, or calcium channel blockers in particular, but they do suggest that persons treated for long-standing asthma may be at increased risk of esophageal adenocarcinoma.     

Paediatric rheumatology: clinical practice review. Physiotherapy and occupational therapy for juvenile chronic arthritis: custom and practice in five centres in the UK, USA and Canada

Calcium channel blockers can block calcium signals that trigger cell differentiation and apoptosis, which are important mechanisms of cancer growth regulation. To ascertain whether calcium channel blocker use was associated with an increased risk of cancer, 750 hypertensive persons age > or = 71 years, with no history of cancer at baseline, were followed from 1988 through 1992. The patients were using either beta-blockers, angiotensin converting enzyme inhibitors or calcium channel blockers (verapamil, nifedipine, and diltiazem; mainly of the short-acting variety). Compared to beta-blockers (n = 424, 28 events), after adjusting for age, gender, race, smoking, body mass index, and number of hospital admissions not related with cancer, the relative risks of cancer (95% confidence interval) for angiotensin converting enzyme inhibitors (n = 124, 6 events) and calcium channel blockers (n = 202, 27 events) were 0.73 (0.30 to 1.78) and 2.02 (1.16 to 3.54), respectively. These findings indicate that calcium channel blocker therapy might increase the risk of cancer. New data are needed in patients using modern calcium channel blocker agents with more gradual absorption. This report should encourage further study of cancer outcomes in elderly patients who are vulnerable to cancer and who are receiving calcium channel blockers.     

Prospective study of calcium channel blocker use, cardiovascular disease, and total mortality among hypertensive women: the Nurses' Health Study

BACKGROUND: In several observational studies, patients prescribed calcium channel blockers had higher risks of cardiovascular diseases and mortality than those prescribed other antihypertensive medications. We explored these associations in the Nurses' Health Study. METHODS AND RESULTS: A total of 14 617 women who reported hypertension and regular use of diuretics, beta-blockers, calcium channel blockers, ACE inhibitors, or a combination in 1988 were included in the analyses. Cardiovascular events and deaths were ascertained through May 1, 1994. We documented 234 cases of myocardial infarction. Calcium channel blocker monodrug users had an age-adjusted relative risk (RR) of myocardial infarction of 2.36 (95% CI, 1.43 to 3.91) compared with those prescribed thiazide diuretics. Women prescribed calcium channel blockers had a higher prevalence of ischemic heart disease. After adjustment for these and other coronary risk factors, the RR was 1.64 (95% CI, 0.97 to 2.77). Comparing the use of any calcium channel blocker (monodrug and multidrug users) with that of any other antihypertensive agent, the adjusted RR was 1.42 (95% CI, 1.01 to 2.01). An association between calcium channel blocker use and myocardial infarction was apparent among women who had ever smoked cigarettes (covariate-adjusted RR, 1.81; 95% CI, 1.20 to 2.72) but not among never-smokers (RR, 0.94; 95% CI, 0.48 to 1.84). CONCLUSIONS: In analyses adjusted only for age, we found a significant elevation in RR of total myocardial infarction among women who used calcium channel blockers compared with those who did not. After adjustment for comorbidity and other covariates, the RR was reduced. Whether the remaining observed elevated risk is real, or a result of residual confounding by indication, or chance, or a combination of the above cannot be evaluated with certainty on the basis of these observational data.     

Pancreas cancer as a second primary malignancy. A population-based study

BACKGROUND: The study of second primary malignancies may give clues to the etiology of various cancers. Little is known about risk factors for pancreatic carcinoma; therefore, its occurrence as a second primary malignancy was investigated. METHODS: Data from the Surveillance, Epidemiology, and End-Results (SEER) program were used for the period from January 1, 1973 through December 31, 1990. Person-years of follow-up for various cancer sites were calculated, excluding the initial 6 months after diagnosis, and were multiplied times the age- and sex-specific incidence rates for pancreas cancer to calculate the expected number of second primary pancreas cancer cases. The observed number of cases was divided by the expected number to estimate the relative risk (RR) of pancreas cancer as a second primary cancer, and 95% confidence limits were calculated. RESULTS: The risk of second primary cancer was elevated after lung cancer for men (RR 1.3, 95% CI 1.0-1.6) and women (RR 2.5, 95% CI 1.9-3.2). An elevation in risk also was found after head and neck cancer in women (RR 1.8, 95% CI 1.2-2.5) and bladder cancer in women (RR 1.5, 95% CI 1.1-2.0), but not in men. Other significant elevations were found after prostate cancer (RR 1.2, 95% CI 1.1-1.3), and a decreased risk was found after lymphoma in men (RR 0.2, 95% CI 0.0-0.8). CONCLUSIONS: Second primary pancreas cancer is increased after tobacco-related malignancies, particularly in females, supporting the role of cigarette smoking as a risk factor for pancreas cancer and suggesting a stronger effect of cigarette smoking for women. The elevation in risk after prostate cancer and the decreased risk after lymphoma in males need to be confirmed in other data sets.     

Use of calcium channel blockers and risk of suicide: ecological findings confirmed in population based cohort study

OBJECTIVE: To investigate possible associations between use of cardiovascular drugs and suicide. DESIGN: Cross sectional ecological study based on rates of use of eight cardiovascular drug groups by outpatients. A population based cohort study including users of drugs to control hypertension. SUBJECTS: The ecological study included 152 of Sweden's 284 municipalities. The cohort study included all inhabitants of one Swedish municipality who during 1988 or 1989 had purchased cardiovascular agents from pharmacies within the municipality. Six hundred and seventeen subjects (18.2%) were classified as users of calcium channel blockers and 2780 (81.8%) as non-users. MAIN OUTCOME MEASURES: Partial correlations (least squares method) between rates of use of cardiovascular drugs and age standardised mortality from suicide in Swedish municipalities. Hazard ratios for risk of suicide with adjustments for difference in age and sex in users of calcium channel blockers compared with users of other hypertensive drugs. RESULTS: Among the Swedish municipalities the use of each cardiovascular drug group except angiotensin converting enzyme inhibitors correlated significantly and positively with suicide rates. After adjustment for the use of other cardiovascular drug groups, as a substitute for the prevalence of cardiovascular morbidity, only the correlation with calcium channel blockers remained significant (r = 0.29, P < 0.001). In the cohort study, five users and four non-users of calcium channel blockers committed suicide during the follow up until the end of 1994. The absolute risk associated with use of calcium channel blockers was 1.1 suicides per 1000 person years. The relative risk, adjusted for differences in age and sex, among users versus non-users was 5.4 (95% confidence interval 1.4 to 20.5). CONCLUSIONS: Use of calcium channel blockers may increase the risk of suicide.     

The effect of N-acetylcysteine on total serum anti-oxidant potential and urinary albumin excretion in critically ill patients

PURPOSE: Calcium channel blockers have been reported to increase the risk of gastrointestinal bleeding. We tested this hypothesis, and also assessed whether beta blockers decrease this risk. SUBJECTS AND METHODS: A nested case-control design within a population-based cohort of all 34,074 new users of beta blockers, angiotensin-converting enzyme (ACE) inhibitors, or calcium channel blockers in Saskatchewan, from 1990 to 1993 and followed up to March 1995, was used. We identified all 311 subjects hospitalized because of gastrointestinal bleeding during this period, each of whom was matched to 10 randomly selected controls. RESULTS: The rate of hospitalization for gastrointestinal bleeding was 3.0 per 1,000 per year. The adjusted rate ratio of gastrointestinal bleeding for current use of calcium channel blockers was 1.1 (95% confidence interval [CI] 0.8 to 1.4) and 0.66 (95% CI 0.44 to 0.98) for beta blockers compared with no current use of anti-hypertensive drugs. The adjusted rate ratio for ACE inhibitor use was 1.0 (95% CI 0.7 to 1.3) while that for diuretic use was 1.4 (95% CI 1.0 to 2.0). CONCLUSIONS: The use of calcium channel blockers does not appear to increase the risk of gastrointestinal bleeding in the first five years of treatment, while beta blockers may prevent this adverse event. The unexpected elevated risk associated with the use of diuretics needs to be investigated further.     

Monoclonal antibody FC-5.01, directed against CD63 antigen, is internalized into cytoplasmic vesicles in the IIB-BR-G human breast cancer cell line

PURPOSE: Benign prostatic hyperplasia is common among men who may be candidates for prostate cancer screening using prostate-specific antigen (PSA) testing. Patterns of PSA testing among men with evidence of benign prostatic hyperplasia have not been studied. METHODS: We examined the prevalence and correlates of a self-reported history of PSA testing. In 1994, 33,028 US health professionals without prostate cancer aged 47 to 85 years provided information on prior PSA testing, lower urinary tract symptoms characteristic of benign prostatic hyperplasia, history of prostatectomy, and prostate cancer risk factors. In 1995, a subset of 7,070 men provided additional information on diagnosis and treatment of benign prostatic hyperplasia. RESULTS: From 39% of men in their 50s to 53% of men in their 80s reported PSA testing in the prior year (P <0.0001 for trend with age). Men were more likely to report PSA testing if they had lower urinary tract symptoms characteristic of benign prostatic hyperplasia (age-adjusted odds ratio for severe symptoms 2.2, 95% confidence interval 1.8 to 2.6), a prior history of prostatectomy (age-adjusted odds ratio 1.1, 95% confidence interval 1.02 to 1.2), or a physician diagnosis of benign prostatic hyperplasia (odds ratio 1.9, 95% confidence interval 1.7 to 2.2; adjusted for age, signs or symptoms of benign prostatic hyperplasia, and prostate cancer risk factors). CONCLUSIONS: These US health professionals reported preferential use of PSA testing among men least likely to benefit from early cancer detection (older men) and among men most likely to have a false-positive PSA result (men with benign prostatic hyperplasia). Physician and patient education are needed to promote more rational and selective use of this screening test.     

Retained glass foreign bodies in wounds: predictive value of wound characteristics, patient perception, and wound exploration

This report describes associations of demographic and health-related characteristics with use of prostate cancer screening. Data are from a random-digit dial survey of Washington State residents. Analyses are restricted to men ages 40-79 years (n = 332) and examine both digital rectal examination (DRE) and blood tests for prostate-specific antigen (PSA) in the previous 2 years. Results are adjusted to be representative of the state's population. In 1996, 53.6% of men received either DRE, PSA, or both. Among those screened, 42% received DRE alone, 15% PSA alone, and 43% both PSA and DRE, and the percentages of men receiving PSA increased markedly with age (30%, ages 40-49 years; 58%, ages 50-59 years; and 77%, ages 60-79 years). After control for other demographic characteristics, the relative odds for any prostate cancer screening were 5.5 for ages 60-79 versus 40-49 years, 2.4 for 16+ versus < or = 12 years of education, and 4.0 for 2+ versus no physician visits in the previous 2 years (all P < 0.05). Characteristics generally associated with good health, including regular exercise and low fat and high fruit and vegetable intakes, were also significantly associated with prostate cancer screening. In conclusion, in 1996, approximately one-half of the men in Washington State over age 40 years had received prostate cancer screening in the previous 2 years. Few men were screened with PSA alone, and the use of PSA as part of prostate cancer screening increased markedly with age. Because PSA screening increases detection of prostate cancer, epidemiological studies of health behavior and cancer risk must carefully control for screening history to avoid detection bias.     

Parietal motor syndrome: a clinical description in 32 patients in the acute phase of pure parietal strokes studied prospectively

Although survival rates are useful for monitoring progress in the early detection and treatment of cancer and are of particular interest to patients with new diagnoses, there are limited population-based estimates of long-term survival rates. We used data collected by the Surveillance, Epidemiology, and End Results Program for cases diagnosed during 1974-1991 and followed through 1992 to estimate relative survival at 5, 10, and 15 years after diagnosis of cancer of the breast, prostate, colon and rectum, and lung. Relative survival after diagnosis of breast and prostate cancer continued to decline up through 15 years after diagnosis, whereas survival after diagnosis of lung and colon or rectal cancer remained approximately constant after 5 and 10 years, respectively. Age-specific patterns of survival varied by site, stage, and demographics. Among patients with localized breast and prostate cancer, women who were younger than age 45 at breast cancer diagnosis and men who were 75 years and older at prostate cancer diagnosis had the poorest relative survival. Relative survival among lung cancer patients decreased with age at diagnosis, regardless of stage or demographics, and age-specific patterns of relative survival for patients with cancer of the colon and rectum differed according to race. Among white patients diagnosed with cancers of the colon and rectum, relative survival did not vary by age at diagnosis; among black patients older than 45 at diagnosis, relative survival decreased with age. This study provides population-based estimates of long-term survival and confirms black/white, male/female, and stage- and age-specific differences for the major cancers.     

Chronic study on the neuronal excitability of the cochlear nuclei of the cat following electrical stimulation

OBJECTIVES: To determine: (i) the prevalence, reasons for, and demographic and psychosocial predictors of prostate cancer screening among a randomly selected sample of men; and (ii) to estimate the community expenditure involved in the screening of asymptomatic men. SUBJECTS AND METHODS: A random sample of men aged 40-79 years was selected from the State Electoral Register of New South Wales, Australia, and asked to complete a computer-assisted telephone interview. The questions determined their demographic characteristics, their subjective health rating compared with others of the same age (5-point scale), the prevalence and reasons for any screening for prostate cancer ('ever screened' and 'screened within the last 12 months'), whether they had undergone a digital rectal examination (DRE), a blood test for prostate-specific antigen (PSA) or transrectal ultrasonography (TRUS), and the prevalence of urinary symptoms. Those who had been screened were then asked to nominate the single most important factor in the decision to undergo prostate cancer screening. To estimate community expenditure, the costs for prostate cancer screening were estimated by applying Medicare schedule charges to the screening and subsequent diagnostic tests performed. Two scenarios were developed to estimate costs: the first used guidelines which do not recommend the use of routine screening for all asymptomatic men, and the second was based on guidelines where the routine use of PSA or TRUS as part of a periodic health examination is not recommended, but the use of DRE in asymptomatic men aged 50-70 years is. RESULTS: Of the 551 eligible participants, 86% completed the interview; 44% of participants reported that they had 'ever' been screened, whilst 23% had been screened in the year before the study. Among those who had been screened, the reason reported most often for screening, apart from symptoms and family history, was the doctor's recommendation after a medical assessment of their prostate cancer risk status. Screening status was predicted both by the age of the man and his symptom score. As a result, the community expenditure in New South Wales for screening among asymptomatic men was estimated to be A$6.4 million and A$5.2 million for the first and second scenarios, respectively. CONCLUSIONS: The results of this study suggest that, despite the recommendations of primary bodies that asymptomatic men not be screened for prostate cancer, screening is occurring at a high level and with significant costs to the healthcare system.     

Prostate cancer in American Indians, New Mexico, 1969 to 1994

PURPOSE: Prostate cancer is the most frequently diagnosed cancer as well as the leading cause of cancer death among American Indian men. MATERIALS AND METHODS: To describe further the occurrence of prostate cancer among American Indian men, we examined population based incidence, treatment, survival and mortality data for American Indians in New Mexico during the 25-year period 1969 to 1994. RESULTS: Although American Indian men have a lower risk of prostate cancer than nonHispanic white men, the incidence and mortality rates are rising for American Indians, and mortality rates are now equal to those for nonHispanic white men. During the 25-year period age adjusted incidence rates for American Indians increased from 42.2/100,000 (95% confidence interval 27.1 to 57.3) to 64.6/100,000 (95% confidence interval 46.2 to 83.0). The burden of prostate cancer among American Indian men compared with nonHispanic white men was reflected in disproportionately high mortality rates in relation to incidence rates. The mortality rates were high because American Indian cases were more advanced at diagnosis, 23.3% of prostate cancers were diagnosed after distant spread had occurred compared with 11.6% for nonHispanic white men and the 5-year relative survival rate was poorer (57.1% compared with 77.6% for nonHispanic white men). CONCLUSIONS: Effective and culturally sensitive cancer control efforts for prostate cancer in American Indian communities are urgently needed.     

Study of prediagnostic selenium level in toenails and the risk of advanced prostate cancer

BACKGROUND: In a recent randomized intervention trial, the risk of prostate cancer for men receiving a daily supplement of 200 microg selenium was one third of that for men receiving placebo. By use of a nested case-control design within a prospective study, i.e., the Health Professionals Follow-Up Study, we investigated the association between risk of prostate cancer and prediagnostic level of selenium in toenails, a measure of long-term selenium intake. METHODS: In 1986, 51,529 male health professionals aged 40-75 years responded to a mailed questionnaire to form the prospective study. In 1987, 33,737 cohort members provided toenail clippings. In 1988, 1990, 1992, and 1994, follow-up questionnaires were mailed. From 1989 through 1994, 181 new cases of advanced prostate cancer were reported. Case and control subjects were matched by age, smoking status, and month of toenail return. Selenium levels were determined by neutron activation. All P values are two-sided. RESULTS: The selenium level in toenails varied substantially among men, with quintile medians ranging from 0.66 to 1.14 microg/g for control subjects. When matched case-control data were analyzed, higher selenium levels were associated with a reduced risk of advanced prostate cancer (odds ratio [OR] for comparison of highest to lowest quintile = 0.49; 95% confidence interval [CI] = 0.25-0.96; P for trend = .11). After additionally controlling for family history of prostate cancer, body mass index, calcium intake, lycopene intake, saturated fat intake, vasectomy, and geographical region, the OR was 0.35 (95% CI = 0.16-0.78; P for trend = .03). CONCLUSIONS: Our results support earlier findings that higher selenium intakes may reduce the risk of prostate cancer. Further prospective studies and randomized trials of this relationship should be conducted.     

Asymptomatic arrhythmias in patients with symptomatic paroxysmal atrial fibrillation and paroxysmal supraventricular tachycardia

BACKGROUND: Paroxysmal atrial fibrillation and paroxysmal supraventricular tachycardia are recognized clinically when patients seek treatment for symptoms due to recurrent arrhythmias; atrial fibrillation also increases the risk of stroke. The frequency with which asymptomatic arrhythmias occur in patients with these arrhythmias is unknown. METHODS AND RESULTS: Twenty-two patients with paroxysmal atrial fibrillation (n = 8) or paroxysmal supraventricular tachycardia (n = 14) were studied for 29 days with two different ambulatory ECG-monitoring techniques to measure the relative frequency of asymptomatic and symptomatic arrhythmias. All class I antiarrhythmic drugs, calcium channel blockers, beta-blockers, and digitalis were withheld. Sustained asymptomatic arrhythmia events (defined as lasting at least 30 seconds) were documented using continuous ambulatory ECG monitoring once weekly for a total of 5 of the 29 study days; symptomatic arrhythmia events were documented using transtelephonic ECG monitoring for all 29 days of the study. In the group of patients with paroxysmal atrial fibrillation, asymptomatic arrhythmia events occurred significantly more frequently than symptomatic arrhythmia events; the mean rates, expressed as events/100 d/patient (95% confidence interval), were 62.5 (40.4, 87.3) and 5.2 (2.7, 9.0) (P < .01); the ratio of the mean rates was 12.1 (5.8, 26.4). In contrast, in the group of patients with paroxysmal supraventricular tachycardia, asymptomatic arrhythmia events were significantly less frequent than symptomatic arrhythmia events; the mean rates were 0.0 (0.0, 5.3) and 7.4 (5.0, 10.6) (P = .02). The ratio of the mean rates was 0.0 (0.0, 0.8). CONCLUSIONS: In a group of patients with paroxysmal atrial fibrillation, sustained asymptomatic atrial fibrillation occurs far more frequently than symptomatic atrial fibrillation. However, it is not known whether asymptomatic atrial fibrillation is a potential risk factor for stroke even when patients are not having symptomatic arrhythmias.     

Prostate-specific antigen in the diagnosis of organ-confined treatable prostate carcinoma

Prostate cancer is now the most common cancer and the second most common cause of death from cancer among men. Several studies have shown a frequency of autopsy-detected cancer of 40% in men over 50 years of age. In contrast, the lifetime probability of prostate cancer being diagnosed clinically is only 8%. Thus histologically documented prostate cancer only becomes clinically relevant if the tumors are > 0.5 cm3 and the life expectancy exceeds 10 years. Therapy with curative intention is only possible for organ confined disease. Because disease specific survival is about 80-90% after 10 years for conservative treatment of organ confined disease, early detection of prostate cancer is useful for patients with a life expectancy > 10 years. Organ confined prostate cancer is usually asymptomatic. The use of prostate specific antigen (PSA) combined with digital rectal examination (DRE) results in a 2-3 fold increase in prostatic carcinoma detection rate, especially of organ confined disease, by PSA. In men with a minimally elevated PSA-value of 4-10 ng/ml (Hybritech Assays), 25% will have a prostatic carcinoma regardless of the finding of the DRE, which would have reached clinical significance in the follow-up. The indication for biopsy should be established at an early date. There is no support for the common opinion that early detection programs detect clinically unimportant cancers. 95% of tumor volumes are > 0.5 cm3. Furthermore only 3-5% of subjects show prostate cancer in detection programs though 8% will develop clinical symptoms of prostate cancer during their lifetime. This difference is a reason for longitudinal programs with PSA and DRE control once a year, as proposed by the American Cancer Society and the American and Canadian Urological Association, in contrast to other health care organizations, which would wait with general screening until data from prospective randomized trials with beneficial effects of screening are available. To introduce prostate cancer therapy with curative intention for symptomatic patients as well, the cancer should be detected below a PSA level of 10 ng/ml. Insufficient specificity of PSA (2-4 patients have to undergo biopsies to detect one cancer patient) is still an unsolved problem.     

Asymptomatic incidence and duration of prostate cancer

Prostate cancer is known as a disease with an extremely high prevalence relative to its clinical incidence in the population. The combination of preclinical incidence and duration that could yield this phenomenon is of tremendous interest to researchers trying to understand the natural history of the disease and to develop efficient screening strategies. In this article, the authors present estimates of the age-specific asymptomatic incidence and average preclinical duration of prostate cancer. The methodological approach is to first estimate the age-specific incidence of new (stage AI) prostate cancers using preclinical prevalence data from autopsy studies performed between 1941 and 1964 and clinical incidence data for the years 1960-1986 from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. Then, the preclinical prevalence estimates are divided by the derived preclinical incidence estimates to yield estimates of the average duration of asymptomatic disease. The estimated mean duration among white men is between 11 and 12 years and appears to be approximately 1 year shorter for blacks than for whites. Comparison of the lifetime risks of preclinical and clinical disease suggests that approximately 75% of prostate cancers will never become diagnosed if clinical incidence remains at levels observed in 1984-1986, prior to the introduction of prostate-specific antigen (PSA) screening in the population.     

Screening for prostate cancer in asymptomatic men: clinical, legal, and ethical implications

PURPOSE/OBJECTIVES: To describe the opposing recommendations of the major medical organizations related to screening for prostate cancer and to explore the impact of these opposing recommendations on advanced practice nurses (APNs) who are in a position to decide who gets screened and when. DATA SOURCES: Published medical, legal, and economic articles, published legal verdicts and settlements, case law, and news reports. DATA SYNTHESIS: The national recommendations for screening for prostate cancer are conflicting and have legal, economic, and ethical implications for healthcare practitioners. Both the current early diagnostic tests, age- and race-based prostate specific antigen ranges, and the resultant treatment have significant problems and further contribute to the national controversy about whether to screen asymptomatic men. Lack of coverage for early detection of prostate cancer by many managed-care plans and Medicare also contribute to the dilemma practitioners face. However, electing not to screen "at-risk" men may subject APNs to charges of negligence or other legal theories. CONCLUSIONS: Present recommendations by the leading national medical, cancer, and policy organizations related to prostate cancer screening are contradictory. Adding to this national quagmire is the lack of financial support from Medicare and most health maintenance organization plans to pay for early detection of prostate cancer. These conflicting recommendations place APNs in a legally and ethically precarious position. APNs and nurses with patient education responsibilities should individualize decision-making and counsel their asymptomatic patients who may be at risk for prostate cancer about the benefits and complications of screening. IMPLICATIONS FOR NURSING PRACTICE: Considering the multiple implications of the decision to screen for prostate cancer, counseling patients who may be at risk for the disease and involving them and their spouses may be the best approach in deciding whether to screen for prostate cancer in asymptomatic men.     

A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones

BACKGROUND: A high dietary calcium intake is strongly suspected of increasing the risk of kidney stones. However, a high intake of calcium can reduce the urinary excretion of oxalate, which is thought to lower the risk. The concept that a higher dietary calcium intake increases the risk of kidney stones therefore requires examination. METHODS: We conducted a prospective study of the relation between dietary calcium intake and the risk of symptomatic kidney stones in a cohort of 45,619 men, 40 to 75 years of age, who had no history of kidney stones. Dietary calcium was measured by means of a semiquantitative food-frequency questionnaire in 1986. During four years of follow-up, 505 cases of kidney stones were documented. RESULTS: After adjustment for age, dietary calcium intake was inversely associated with the risk of kidney stones; the relative risk of kidney stones for men in the highest as compared with the lowest quintile group for calcium intake was 0.56 (95 percent confidence interval, 0.43 to 0.73; P for trend, < 0.001). This reduction in risk decreased only slightly (relative risk, 0.66; 95 percent confidence interval, 0.49 to 0.90) after further adjustment for other potential risk factors, including alcohol consumption and dietary intake of animal protein, potassium, and fluid. Intake of animal protein was directly associated with the risk of stone formation (relative risk for men with the highest intake as compared with those with the lowest, 1.33; 95 percent confidence interval, 1.00 to 1.77); potassium intake (relative risk, 0.49; 95 percent confidence interval, 0.35 to 0.68) and fluid intake (relative risk, 0.71; 95 percent confidence interval, 0.52 to 0.97) were inversely related to the risk of kidney stones. CONCLUSIONS: A high dietary calcium intake decreases the risk of symptomatic kidney stones.     

A potential role for glucagon in the treatment of drug-induced symptomatic bradycardia

Nine cases of symptomatic bradycardia are presented in which treatment with intravenous glucagon was administered when atropine failed to improve the patient's condition significantly. Although the cause often was not obvious at presentation, all nine subjects took oral medications that could have contributed to the development of symptomatic bradycardia. Eight of nine patients demonstrated clinical improvement 5 to 10 min after glucagon administration, which was consistent with its peak clinical action. Beta-blockers, calcium channel blockers, and digoxin were ultimately thought to have contributed to the majority of these presentations. This report suggests that glucagon may have a role in the treatment of symptomatic bradycardia, particularly in the presence of beta-adrenergic blockade and perhaps calcium channel blockade. Furthermore, the results in these cases suggest that future clinical trials should not be limited to drug-induced symptomatic bradycardia.