Biomedical subjects

Charles A Coltman

Publications and source records attributed to Charles A Coltman.

15 recordsLinked to original sources

PubMed2006

Effect of finasteride on the sensitivity of PSA for detecting prostate cancer.

BACKGROUND: In the Prostate Cancer Prevention Trial (PCPT), men receiving finasteride had a 24.8% lower risk of prostate cancer than men receiving placebo but a higher risk of high-grade cancer. We examined the impact of finasteride on the sensitivity and area under the receiver operating characteristic curve (AUC) of prostate-specific antigen (PSA) for detecting prostate cancer. METHODS: We studied men in the placebo and finasteride groups of the PCPT who had a prostate biopsy and concurrent PSA tests during the 7-year study. We compared the placebo and finasteride groups for sensitivity and AUC of PSA for the detection of all prostate cancer, of Gleason grade 7 or higher prostate cancer, and of Gleason grade 8 or higher prostate cancer. All statistical tests were two-sided. RESULTS: Of 5112 men in the placebo group, prostate cancer was detected in 1111. Gleason tumor grade was available for 1100 men, of whom 240 had grade 7 or higher and 55 had grade 8 or higher. Of 4579 men in the finasteride group, 695 had prostate cancer. Gleason grade was available for 686 men, of whom 264 had grade 7 or higher and 81 had grade 8 or higher. The AUC of PSA for all outcomes was greater for the finasteride group than the placebo group. For detecting prostate cancer versus no cancer, the AUCs were 0.757 and 0.681, respectively (P < .001); for detecting Gleason grade > or = 7 versus < or = 6 or no cancer, the AUCs were 0.838 and 0.781, respectively (P = .003); and for detecting Gleason grade > or = 8 versus < or = 7 or no cancer, the AUCs were 0.886 and 0.824, respectively (P = .071). The sensitivity of PSA was higher for men in the finasteride group than in the placebo group at all PSA cutoffs matched by specificity. CONCLUSIONS: PSA had statistically significantly better sensitivity and AUC for detecting prostate cancer in the finasteride arm of the PCPT than in the placebo arm. This bias would be expected to contribute to greater detection of all grades of prostate cancer with finasteride.

Aged↗

PubMed2006

Assessing prostate cancer risk: results from the Prostate Cancer Prevention Trial.

BACKGROUND: Prostate-specific antigen (PSA) testing is the primary method used to diagnose prostate cancer in the United States. Methods to integrate other risk factors associated with prostate cancer into individualized risk prediction are needed. We used prostate biopsy data from men who participated in the Prostate Cancer Prevention Trial (PCPT) to develop a predictive model of prostate cancer. METHODS: We included 5519 men from the placebo group of the PCPT who underwent prostate biopsy, had at least one PSA measurement and a digital rectal examination (DRE) performed during the year before the biopsy, and had at least two PSA measurements performed during the 3 years before the prostate biopsy. Logistic regression was used to model the risk of prostate cancer and high-grade disease associated with age at biopsy, race, family history of prostate cancer, PSA level, PSA velocity, DRE result, and previous prostate biopsy. Risk equations were created from the estimated logistic regression models. All statistical tests were two-sided. RESULTS: A total of 1211 (21.9%) men were diagnosed with prostate cancer by prostate biopsy. Variables that predicted prostate cancer included higher PSA level, positive family history of prostate cancer, and abnormal DRE result, whereas a previous negative prostate biopsy was associated with reduced risk. Neither age at biopsy nor PSA velocity contributed independent prognostic information. Higher PSA level, abnormal DRE result, older age at biopsy, and African American race were predictive for high-grade disease (Gleason score > or =7) whereas a previous negative prostate biopsy reduced this risk. CONCLUSIONS: This predictive model allows an individualized assessment of prostate cancer risk and risk of high-grade disease for men who undergo a prostate biopsy.

Black or African American↗

PubMed2006

The prostate cancer prevention trial: design, biases and interpretation of study results.

PURPOSE: We describe the complexities of the study design of the PCPT and how they influenced the end point chosen, trial implementation, analysis and interpretation of the results. MATERIALS AND METHODS: Data from the PCPT are provided to evaluate and quantify the potential biases of this trial design. RESULTS: Six potential sources of bias, including prostate specific antigen, digital rectal examination, prostate biopsy technique, study medication nonadherence and contamination, and transurethral prostate resection are presented. These biases resulted in the need for the end of study biopsy to evaluate the trial objectives. CONCLUSIONS: There were a large number of known and potential biases that worked for and against finasteride. Because of the trial design and inherent biases, it is imperative that interim biopsy results should be interpreted with caution. While the period prevalence end point that relied on an end of study biopsy was perhaps not the most clinically relevant, it was the only way to remove as much bias as possible and meet the study objective of determining if finasteride could decrease the risk of prostate cancer. The success of the PCPT depended on constant scrutiny by the Data and Safety Monitoring Committee to monitor these biases. The design and biopsy assumptions outlined at the inception of the trial were met, including adherence and contamination rates, the for-cause biopsy rate and the final percent of men with study end points.

Bias↗

PubMed2005

Erectile dysfunction and subsequent cardiovascular disease.

CONTEXT: The risk factors for cardiovascular disease and erectile dysfunction are similar. OBJECTIVE: To examine the association of erectile dysfunction and subsequent cardiovascular disease. DESIGN, SETTING, AND PARTICIPANTS: Men aged 55 years or older who were randomized to the placebo group (n = 9457) in the Prostate Cancer Prevention Trial at 221 US centers were evaluated every 3 months for cardiovascular disease and erectile dysfunction between 1994 and 2003. Proportional hazards regression models were used to evaluate the association of erectile dysfunction and cardiovascular disease. In an adjusted model, covariates included age, body mass index, blood pressure, serum lipids, diabetes, family history of myocardial infarction, race, smoking history, physical activity, and quality of life. MAIN OUTCOME MEASURES: Erectile dysfunction and cardiovascular disease. RESULTS: Of the 9457 men randomized to placebo, 8063 (85%) had no cardiovascular disease at study entry; of these men, 3816 (47%) had erectile dysfunction at study entry. Among the 4247 men without erectile dysfunction at study entry, 2420 men (57%) reported incident erectile dysfunction after 5 years. After adjustment, incident erectile dysfunction was associated with a hazard ratio of 1.25 (95% confidence interval [CI], 1.02-1.53; P = .04) for subsequent cardiovascular events during study follow-up. For men with either incident or prevalent erectile dysfunction, the hazard ratio was 1.45 (95% CI, 1.25-1.69; P<.001). For subsequent cardiovascular events, the unadjusted risk of an incident cardiovascular event was 0.015 per person-year among men without erectile dysfunction at study entry and was 0.024 per person-year for men with erectile dysfunction at study entry. This association was in the range of risk associated with current smoking or a family history of myocardial infarction. CONCLUSIONS: Erectile dysfunction is a harbinger of cardiovascular clinical events in some men. Erectile dysfunction should prompt investigation and intervention for cardiovascular risk factors.

Aged↗

PubMed2005

Impact of the year 2000 Medicare policy change on older patient enrollment to cancer clinical trials.

PURPOSE: A prior analysis by the Southwest Oncology Group (SWOG) showed that women and African American patients were adequately represented on cancer clinical treatment trials but that older patients were substantially underrepresented. Twenty-five percent of patients > or = 65 years old were enrolled onto SWOG trials from 1993 to 1996, whereas 63% of all patients with cancer were > or = 65 years old. Recognition of this under-representation led to a change in Medicare policy in 2000 to include coverage of routine patient care costs of clinical trials. We conducted an updated analysis of accrual trends. METHODS: The proportions of enrollment onto SWOG treatment trials by sex, race/ethnicity, and age (> or = 65 years) were computed for the years 1997 to 2000; corresponding rates in the United States were derived from US Census and National Cancer Institute Surveillance, Epidemiology, and End results data. Additionally, method of payment data were analyzed over time (1993 to 2003) to assess whether patterns in method of payment changed with the new Year 2000 Medicare policy on clinical trials coverage. RESULTS: The results showed continued adequate representation by sex and race/ethnicity. Older patient accrual on SWOG trials increased significantly since 2000, with 31% of patients > or = 65 years old enrolled from 1997 to 2000 and 38% enrolled from 2001 to 2003 (v 25% from 1993 to 1996). The percentage of patients using Medicare plus supplemental insurance also increased beginning in 2000, whereas the percentage of patients using Medicare alone remained the same. CONCLUSION: Method of payment analyses provided evidence that the Year 2000 Medicare policy change had a positive impact, but only for those patients with supplemental private coverage of coinsurance costs. Improvements in the Medicare payment structure could further increase older patient participation in clinical trials.

Aged↗

PubMed2005

Operating characteristics of prostate-specific antigen in men with an initial PSA level of 3.0 ng/ml or lower.

CONTEXT: Three fourths of US men older than 50 years have been screened with prostate-specific antigen (PSA) for prostate cancer. OBJECTIVE: To estimate the receiver operating characteristic (ROC) curve for PSA. DESIGN, SETTING, AND PARTICIPANTS: Calculation of PSA ROC curves in the placebo group of the Prostate Cancer Prevention Trial, a randomized, prospective study conducted from 1993 to 2003 at 221 US centers. Participants were 18 882 healthy men aged 55 years or older without prostate cancer and with PSA levels less than or equal to 3.0 ng/mL and normal digital rectal examination results, followed up for 7 years with annual PSA measurement and digital rectal examination. If PSA level exceeded 4.0 ng/mL or rectal examination result was abnormal, a prostate biopsy was recommended. After 7 years of study participation, an end-of-study prostate biopsy was recommended in all cancer-free men. MAIN OUTCOME MEASURES: Operating characteristics of PSA for prostate cancer detection, including sensitivity, specificity, and ROC curve. RESULTS: Of 8575 men in the placebo group with at least 1 PSA measurement and digital rectal examination in the same year, 5587 (65.2%) had had at least 1 biopsy; of these, 1225 (21.9%) were diagnosed with prostate cancer. Of 1213 cancers with Gleason grade recorded, 250 (20.6%) were Gleason grade 7 or greater and 57 (4.7%) were Gleason grade 8 or greater. The areas under the ROC curve (AUC) for PSA to discriminate any prostate cancer vs no cancer, Gleason grade 7 or greater cancer vs no or lower-grade cancer, and Gleason grade 8 or greater cancer vs no or lower-grade cancer were 0.678 (95% confidence interval [CI], 0.666-0.689), 0.782 (95% CI, 0.748-0.816), and 0.827 (95% CI, 0.761-0.893), respectively (all P values <.001 for AUC vs 50%). For detecting any prostate cancer, PSA cutoff values of 1.1, 2.1, 3.1, and 4.1 ng/mL yielded sensitivities of 83.4%, 52.6%, 32.2%, and 20.5%, and specificities of 38.9%, 72.5%, 86.7%, and 93.8%, respectively. Age-stratified analyses showed slightly better performance of PSA in men younger than 70 years vs those 70 years or older with AUC values of 0.699 (SD, 0.013) vs 0.663 (SD, 0.013) (P = .03). CONCLUSION: There is no cutpoint of PSA with simultaneous high sensitivity and high specificity for monitoring healthy men for prostate cancer, but rather a continuum of prostate cancer risk at all values of PSA.

Aged↗

PubMed2005

Estimated impact of the Prostate Cancer Prevention Trial on population mortality.

BACKGROUND: The potential public health impact of the recently completed Prostate Cancer Prevention Trial (PCPT) is debated. The results indicated that the period prevalence of prostate cancer was reduced by 24.8% due to finasteride, whereas an increase in the rate of high-grade tumors (Gleason score 8-10) among men who were diagnosed with cancer also was found (5.0% in the PCPT placebo arm vs. 11.9% in the PCPT finasteride arm). Whether the increased Gleason score was valid or was a histologic artifact is under investigation. METHODS: The authors estimated the number of person-years saved assuming a 24.8% reduction in the incidence of prostate cancer for 5 years among United States males age > or = 55 years. Scenarios for different proportions of patients with high-grade Gleason scores also were considered. RESULTS: With a 24.8% reduction in the number of men with newly diagnosed prostate cancer, the authors estimated that 316,760 person-years would be saved due to finasteride in the United States. An absolute increase of 6.9% in the proportion of men with high-grade tumors in the United States cancer population (corresponding to the difference between the rates on the placebo and finasteride arms of the PCPT) would reduce the number of person-years saved to 262,567. For each absolute increase of 5% in the proportion of patients with high-grade tumors, the number of person-years saved would be reduced by approximately 39,000. CONCLUSIONS: The results of the PCPT may have a major impact on population mortality from prostate cancer if they are applied clinically. The potential detrimental effects of an increased rate of patients who have prostate cancer with high-grade Gleason scores would be outweighed by a reduction in incidence.

Finasteride↗

PubMed2005

Designing the Selenium and Vitamin E Cancer Prevention Trial (SELECT).

Prostate cancer continues to be a major health threat, especially among African American men. The Selenium and Vitamin E Cancer Prevention Trial (SELECT), which opened on July 25, 2001, was planned to study possible agents for the prevention of prostate cancer in a population of 32,400 men in the United States, including Puerto Rico, and Canada. SELECT is a phase III randomized, placebo-controlled trial of selenium (200 microg/day from L-selenomethionine) and/or vitamin E (400 IU/day of all rac alpha-tocopheryl acetate) supplementation for a minimum of 7 years (maximum of 12 years) in non-African American men at least 55 years of age and African American men at least 50 years of age. SELECT is a large, simple trial that conforms as closely as possible with community standards of care. This commentary discusses the design problems the SELECT investigators had to resolve in developing the trial, including the role of prostate cancer screening, the best forms and doses of the study agents, and estimation of the event (prostate cancer) rate of men on the placebo arm.

Black or African American↗

PubMed2004

Prevalence of prostate cancer among men with a prostate-specific antigen level < or =4.0 ng per milliliter.

BACKGROUND: The optimal upper limit of the normal range for prostate-specific antigen (PSA) is unknown. We investigated the prevalence of prostate cancer among men in the Prostate Cancer Prevention Trial who had a PSA level of 4.0 ng per milliliter or less. METHODS: Of 18,882 men enrolled in the prevention trial, 9459 were randomly assigned to receive placebo and had an annual measurement of PSA and a digital rectal examination. Among these 9459 men, 2950 men never had a PSA level of more than 4.0 ng per milliliter or an abnormal digital rectal examination, had a final PSA determination, and underwent a prostate biopsy after being in the study for seven years. RESULTS: Among the 2950 men (age range, 62 to 91 years), prostate cancer was diagnosed in 449 (15.2 percent); 67 of these 449 cancers (14.9 percent) had a Gleason score of 7 or higher. The prevalence of prostate cancer was 6.6 percent among men with a PSA level of up to 0.5 ng per milliliter, 10.1 percent among those with values of 0.6 to 1.0 ng per milliliter, 17.0 percent among those with values of 1.1 to 2.0 ng per milliliter, 23.9 percent among those with values of 2.1 to 3.0 ng per milliliter, and 26.9 percent among those with values of 3.1 to 4.0 ng per milliliter. The prevalence of high-grade cancers increased from 12.5 percent of cancers associated with a PSA level of 0.5 ng per milliliter or less to 25.0 percent of cancers associated with a PSA level of 3.1 to 4.0 ng per milliliter. CONCLUSIONS: Biopsy-detected prostate cancer, including high-grade cancers, is not rare among men with PSA levels of 4.0 ng per milliliter or less--levels generally thought to be in the normal range.

Aged↗

PubMed2004

Implementation of the Prostate Cancer Prevention Trial (PCPT).

The Prostate Cancer Prevention Trial is a randomized double blind chemoprevention trial of 18,882 men. It is designed to test the difference in the histologically proven prostate cancer prevalence between a group of participants given finasteride and another given placebo for 7 years. We present an overview of the study design, details of the administrative structure of the study and a description of the successful implementation of the accrual phase.

Chemoprevention↗

PubMed2003

Estimating the impact of new clinical trial proven cancer therapy and cancer chemoprevention on population mortality: the Karnofsky Memorial lecture.

PURPOSE: The 31-year "war on cancer" has focused largely on therapeutic (as opposed to preventative) cancer research, which, in both the public and private sector, has received the majority of funding. Meanwhile the prevention of cancer has received less attention. PATIENTS AND METHODS: We analyzed eight positive phase III therapeutic trials of the Southwest Oncology Group, and estimated how the observed improvements in survival from the new therapies would impact mortality at the population level (utilizing Surveillance, Epidemiology, and End Results-data). We compared these results with the impact of the Prostate Cancer Prevention Trial. The measure of impact was person-years saved in the first 5 years. RESULTS: Estimates of person-years saved in the first 5 years included 28,534 from improved treatment of localized bladder cancer and 26,241 from improved treatment of advanced lung cancer, representing, respectively, 31.4% and 2.8% of the person-years which could have been saved for these diseases (the "relative impact of new treatment on survival"). The new therapies from all eight positive phase III trials would have saved 114,641 person-years over the first 5 years. The estimate from the Prostate Cancer Prevention Trial was 99,441 person-years over the first 5 years. CONCLUSION: New cancer therapies have a proven and quantifiable impact on population mortality. Successful cancer prevention has a similarly large impact. However, federal funding for cancer prevention is less than half that of cancer treatment. As a result of its enormous potential for extending life, cancer prevention warrants increased funding and support from federal funding agencies.

Antineoplastic Agents↗

PubMed2003

The influence of finasteride on the development of prostate cancer.

BACKGROUND: Androgens are involved in the development of prostate cancer. Finasteride, an inhibitor of 5alpha-reductase, inhibits the conversion of testosterone to dihydrotestosterone, the primary androgen in the prostate, and may reduce the risk of prostate cancer. METHODS: In the Prostate Cancer Prevention Trial, we randomly assigned 18,882 men 55 years of age or older with a normal digital rectal examination and a prostate-specific antigen (PSA) level of 3.0 ng per milliliter or lower to treatment with finasteride (5 mg per day) or placebo for seven years. Prostate biopsy was recommended if the annual PSA level, adjusted for the effect of finasteride, exceeded 4.0 ng per milliliter or if the digital rectal examination was abnormal. It was anticipated that 60 percent of participants would have prostate cancer diagnosed during the study or would undergo biopsy at the end of the study. The primary end point was the prevalence of prostate cancer during the seven years of the study. RESULTS: Prostate cancer was detected in 803 of the 4368 men in the finasteride group who had data for the final analysis (18.4 percent) and 1147 of the 4692 men in the placebo group who had such data (24.4 percent), for a 24.8 percent reduction in prevalence over the seven-year period (95 percent confidence interval, 18.6 to 30.6 percent; P<0.001). Tumors of Gleason grade 7, 8, 9, or 10 were more common in the finasteride group (280 of 757 tumors [37.0 percent], or 6.4 percent of the 4368 men included in the final analysis) than in the placebo group (237 of 1068 tumors [22.2 percent], P<0.001 for the comparison between groups; or 5.1 percent of the 4692 men included in the final analysis, P=0.005 for the comparison between groups). Sexual side effects were more common in finasteride-treated men, whereas urinary symptoms were more common in men receiving placebo. CONCLUSIONS: Finasteride prevents or delays the appearance of prostate cancer, but this possible benefit and a reduced risk of urinary problems must be weighed against sexual side effects and the increased risk of high-grade prostate cancer.

5-alpha Reductase Inhibitors↗

PubMed2003

Southwest Oncology Group studies in bladder cancer.

Over 50,000 patients are diagnosed annually with bladder cancer, and approximately 10,000 eventually will die of their disease. Thus, the Southwest Oncology Group (SWOG) Genitourinary Cancer Committee is committed to the study of therapeutic interventions in patients with superficial, invasive, and metastatic bladder cancer. In the past 15 years, SWOG has completed six Phase III, randomized trials. Studies in patients with superficial disease have established the role of bacillus Calmette-Guerin in patient management; and a large, randomized trial has outlined the value of neoadjuvant chemotherapy and cystectomy in patients with advanced disease. SWOG plans to build on this model by evaluating patients with residual disease after chemotherapy for possible bladder preservation while evaluating more chemotherapy for patients with persistent disease. The Genitourinary Cancer Committee will continue to seek new, active agents for metastatic disease and will participate in and support large, Phase III, international trials that seek to improve current regimens. SWOG accomplishments in bladder cancer are highlighted, and future strategies are discussed.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2003

Prevention of prostate cancer with finasteride: US/European perspective.

PURPOSE: Prostate cancer is the most common male cancer, affecting one man in six. Prevention of this disease, even in a subset of patients would have a significant impact on public health. The results of the National Cancer Institute-sponsored Prostate Cancer Prevention Trial demonstrate that finasteride causes a substantial risk reduction across all known risk groups. We herein amplify on the results of this trial to assist patients and physicians in reaching individualized decisions. MATERIALS AND METHODS: The results of the Prostate Cancer Prevention Trial were reviewed. RESULTS: The PCPT demonstrated a 24.8% reduction in prostate cancer risk with the administration of finasteride. High-grade cancers were noted in 6.4% of finasteride patients compared to 5.1% of men receiving placebo. The increase in high-grade tumors was seen within one year of finasteride exposure and did not increase over time. This observation, combined with previous evidence demonstrating an alteration in cytologic and architectural features of prostate cancer with hormonal therapy suggests that the differences in high-grade disease may be an artifact and that application of Gleason grading to these tumors may not be appropriate. DISCUSSION: Men should be presented the benefits and risks of taking finasteride and be assisted in integrating their sexual and urinary symptoms into their decision-making process. Blanket statements for or against the use of this medication ignore patient preferences and differential risk-benefit profiles from finasteride.

Aged↗

PubMedDate not supplied

The person-years saved model and other methodologies for assessing the population impact of cancer-prevention strategies.

The results of the Prostate Cancer Prevention Trial spurred debate because finasteride was found to reduce the period prevalence of prostate cancer by about 25% while also increasing the rate of high-grade prostate cancers. Assessing how finasteride would impact mortality at the population level is key to evaluating the public health implications of these results. Any model for evaluating the impact of chemoprevention at the population level will involve methods for assigning weights to competing outcomes of the chemoprevention. The person-years saved model, which uses survival to weigh outcomes, assesses the impact on population mortality and has particular strengths. The person-years saved model shows that more than 300,000 person-years would be saved during a period of 10 years with the widespread use of finasteride, assuming no change in the rate of high-grade prostate cancers. The rate of high-grade prostate cancers in the population, about 20% in any given year, would have to nearly triple to 60% for the net positive impact of finasteride to be zero. The person-years saved model shows that the administration of finasteride is likely to result in a net positive impact of finasteride on population mortality, even with an increase in the rate of high-grade prostate cancers. Future models may use other outcomes to assess population impact, including economic, quality-of-life, or various combinations of outcomes.

Chemoprevention↗