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Biomedical subjects

A Krongrad

Publications and source records attributed to A Krongrad.

At least 19 recordsLinked to original sources
PubMed2001

Radiation therapy in non-surgically-treated nonmetastatic prostate cancer: geographic and demographic variation.

OBJECTIVES: To examine the geographic variation in the use of radiation to treat nonmetastatic prostate cancer and to identify factors that explain the variation in the United States. METHODS: This study was based on data from the nine geographic regions of the Surveillance, Epidemiology, and End Results Program for 1983 through 1996. Patients with localized or regional prostate cancer who did not undergo surgical treatment were included in the analysis. Logistic regression analysis was used to investigate the influence of geographic and demographic factors on the use of radiation. The squared multiple correlation coefficient R(2) was used to measure the proportion of variation in the selection of radiation explained by each factor of interest. RESULTS: Compared with San Francisco, the adjusted odds ratios for 6 of the 8 geographic areas had highly significant P values, suggesting the use of radiation therapy varies from region to region. However, geographic location only explained less than 3% of the total variation in the use of radiation. The geographic location explained a much higher proportion of variation in the youngest (younger than 55 years) and the oldest (80 years old or older) groups. Overall, age was the most important factor that influenced the use of radiation. CONCLUSIONS: The finding that geographic location explains a significant proportion of the variation in the use of radiation in the youngest and oldest age groups demonstrates the outcome of longstanding controversies in the nonsurgical treatment of prostate cancer. Documenting the impact of the interaction of age and geographic location on the treatment approaches provides for better understanding of the impact of patients and physicians making clinical decisions in the management of nonmetastatic prostate cancer.

Black or African American↗
PubMed2001

Overall and disease-specific survival after radical prostatectomy: geographic uniformity.

OBJECTIVES: To examine whether the survival (both overall and disease-specific) of patients who underwent radical prostatectomy varies from region to region in the United States. Previous reports have documented a geographic variation in the use of radical prostatectomy. METHODS: This study was based on the data from nine geographic regions of the Surveillance, Epidemiology, and End Results Program (SEER) for 1983 through 1992. Patients with localized prostate cancer who underwent radical prostatectomy were included in the analysis. A proportional hazards model was used to investigate whether geographic variation is associated with both overall and disease-specific survival. RESULTS: From 1983 through 1992, the SEER Program collected information from nine geographic regions on 66,293 patients with localized prostate cancer (mean age 71.8 +/- 8.4 years), who had SEER grade codes of 1, 2, or 3. Of these patients, 11,429 (mean age 65.3 +/- 6.5 years) underwent radical prostatectomy and lymph node dissection. Cox's proportional hazards analyses revealed that the impact of geographic location on both overall and disease-specific survival in patients who underwent radical prostatectomy was not statistically significant. CONCLUSIONS: The results of this study indicate that the survival (both overall and disease-specific) of patients with localized prostate cancer who underwent radical prostatectomy is not influenced by geographic location, suggesting that their survival is relatively uniform across the geographic regions in the United States.

Aged↗
PubMed2000

Prostate-specific antigen as a marker of prostate disease.

Serum prostate markers, in particular prostate-specific antigen (PSA), have truly revolutionised all aspects of the management of men with prostatic carcinoma (PCa), the most important application being related to its early detection and screening. Several studies have shown the clinical utility of PSA levels for staging patients with PCa, especially when associated with other parameters, such as tumour grade, digital rectal examination and transrectal ultrasound findings, to establish the likelihood of disease extension outside the gland and of positive lymph nodes. Also, serum PSA levels are useful in monitoring patients either after the initial diagnosis of PCa or following therapy.

Carcinoma↗
PubMed2000

Laparoscopic radical prostatectomy.

The radical prostatectomy has been modified over the years. With the introduction to the modern operating room of robots and other tools has come the latest modification: the laparoscopic radical prostatectomy (LRP), first described almost 10 years ago. In the past 2 years, the technique of LRP has been made standard, reproducible, and efficient. The LRP virtually eliminates the physical and emotional toll of radical prostate surgery and reduces blood loss, hospital time, and cost. Published series demonstrate oncologic and functional results comparable with and perhaps better than what is seen with open radical prostatectomy. The LRP is a standard surgical technique in a growing number of medical centers, with world experience estimated at 500 cases. The LRP offers the urologic community a rare opportunity for tangibly improving care.

Humans↗
PubMed2000

Radical prostatectomy: geographic and demographic variation.

OBJECTIVES: Previous reports have documented a geographic variation in the use of radical prostatectomy. We examined whether this phenomenon can be explained by factors other than geography alone. METHODS: This study was based on the data from nine geographic regions of the Surveillance, Epidemiology, and End Results (SEER) program for the years 1983 through 1994. Patients with localized or regional prostate cancer were included in the analysis. Logistic regression analysis was used to investigate the influence of geographic and demographic factors on the use of radical prostatectomy. The squared multiple correlation coefficient R(2) was used to measure the proportion of variation in the selection of radical prostatectomy explained by each factor of interest. RESULTS: As previously reported, the use of radical prostatectomy was significantly associated with geographic location; the degree of geographic variation varied as a function of age and was most dramatic in the youngest (younger than 45 years) and the oldest (75 years or older) groups. Overall, however, geography explained less than 2% of the total variation in the use of radical prostatectomy. Age was the most important factor that influenced the use of radical prostatectomy. CONCLUSIONS: Geography explains only a small proportion of the variation in the use of radical prostatectomy. In fact, of the factors examined, only age appeared to meaningfully explain the variation in the use of radical prostatectomy. Overall, our ability to explain the variation in the use of radical prostatectomy remains meager, and new factors must be identified if we are to better understand how patients and physicians make clinical decisions.

Adult↗
PubMed1999

The effect of marital status on survival in late-stage cancer patients: an analysis based on surveillance, epidemiology, and end results (SEER) data, in the United States.

Recently findings that marital status is associated with survival in patients with late-stage prostate cancer led to an examination of the generalizability of this association for all cancers. We restricted the investigation to patients with late-stage cancer using population-based data collected from 261,070 patients with late-stage cancer at multiple sites in the United States to determine relations between marital status and survival. After controlling for age, race, and treatment, married patients with cancers of all major primary sites had significantly better survival than single, separated, divorced, or widowed patients. Although single and widowed patients had the poorest prognosis in general, single patients appeared to show the most consistently poor survival across the different types of cancers. Survival differences by marital status were more pronounced in men than in women. This observation raises the possibility that some characteristics associated with being married delay death from cancer. These findings require investigators to ask new questions about the effect of being married and its possible correlates, such as general health status, access to health care, and socioeconomic status. Known correlates of marital status, such as available social support and social isolation also merit attention in relation to these findings.

Journal Article↗
PubMed1998

Dimensions of quality of life in prostate cancer.

PURPOSE: Quality of life research in prostate cancer involves the use of many questionnaires and specific items that may be partly redundant. We examine dimensions of quality of life in prostate cancer in the hope of somewhat simplifying communication of basic information. MATERIALS AND METHODS: We analyzed cross-sectional survey data on quality of life in patients with prostate cancer belonging to a Southern California HMO. Quality of life was assessed with the University of California, Los Angeles prostate cancer index. Scree plot and parallel analysis were used to identify factors for extraction and orthogonal (varimax) rotation to examine scale loadings. RESULTS: Four extracted factors explained a cumulative variance of 86%. The 8 physical and emotional scales loaded on 1 general factor explained 41% of the cumulative variance. Urinary function and bother, sexual function and bother, and bowel function and bother scales loaded on factors explained 16, 15 and 14% of the cumulative variance, respectively. CONCLUSIONS: The observation of only 1 general quality of life factor diverges from consistent previous observations of distinct physical and emotional factors in other types of patients, and the tight interaction of emotional and physical scales supports the vulnerability hypothesis, "with age the increasing interactions across dimensions of health leave a patient vulnerable in all when any is affected." The tight interaction of physical and emotional scales in these but not other patients opens the door theoretically to better evaluation of and targeting of health services for patients with prostate cancer.

Aged↗
PubMed1998

Disease specific death after external beam radiation of prostate cancer.

Our purpose in this paper was to examine the association of age, race, stage, grade, and calendar period with and generate estimates of disease-specific mortality after external beam radiation for prostate cancer. Using data from the Surveillance Epidemiology and End Results Program, we fit proportional hazards models and used life table analyses to estimate survival distribution. High grade and stage, black race, and early calendar period were individually associated with disease-specific mortality. Disease-specific survival ranged from 43% for poorly differentiated regional cancer diagnosed in 1978-1982 to 88% for well differentiated localized cancer diagnosed in 1983-1987. Estimates of disease-specific mortality varied by grade, stage and calendar period of diagnosis. These estimates may be considered in evaluating future treatments.

Journal Article↗
PubMed1998

Decreased incidence of prostate cancer with selenium supplementation: results of a double-blind cancer prevention trial.

OBJECTIVE: To test if supplemental dietary selenium is associated with changes in the incidence of prostate cancer. PATIENTS AND METHOD: A total of 974 men with a history of either a basal cell or squamous cell carcinoma were randomized to either a daily supplement of 200 microg of selenium or a placebo. Patients were treated for a mean of 4.5 years and followed for a mean of 6.5 years. RESULTS: Selenium treatment was associated with a significant (63%) reduction in the secondary endpoint of prostate cancer incidence during 1983-93. There were 13 prostate cancer cases in the selenium-treated group and 35 cases in the placebo group (relative risk, RR=0.37, P=0.002). Restricting the analysis to the 843 patients with initially normal levels of prostate-specific antigen (< or = 4 ng/mL), only four cases were diagnosed in the selenium-treated group and 16 cases were diagnosed in the placebo group after a 2 year treatment lag, (RR=0.26 P=0.009). There were significant health benefits also for the other secondary endpoints of total cancer mortality, and the incidence of total, lung and colorectal cancer. There was no significant change in incidence for the primary endpoints of basal and squamous cell carcinoma of the skin. In light of these results, the 'blinded' phase of this trial was stopped early. CONCLUSIONS: Although selenium shows no protective effects against the primary endpoint of squamous and basal cell carcinomas of the skin, the selenium-treated group had substantial reductions in the incidence of prostate cancer, and total cancer incidence and mortality that demand further evaluation in well-controlled prevention trials.

Basal Cell Carcinoma↗
PubMed1998

Ex vivo comparison of four lithotripters commonly used in the ureter: what does it take to perforate?

We hoped to determine the number of pulses and energy needed to create acute ureteral perforations with four different lithotripters in a reproducible ex vivo model. A simple model was constructed to control variables in the testing such as wall thickness, intraluminal pressure, distance between the probe tip and ureter, and power delivered to tissue. Segments of domestic pig ureter were prepared and fixed in position in a normal saline (NS) bath at room temperature. We then attempted perforation with the holmium:YAG (HoL) laser, coumarin pulsed-dye laser (CdL), electrohydraulic lithotripter (EHL), and pneumatic impactor (PI) by placing the instrument probes at right angles to the ureteral wall. The ureter was filled with a methylene blue-stained solution of NS at 90 cm H2O pressure via a urodynamics catheter, and perforation was recorded on initial extravasation of dye. The endpoints measured were time to perforation and total energy required. At 0.5 mm of separation between the wall and probe, the HoL perforated the ureter in an average of 2 seconds and 0.01 kJ delivered at 5 W (10 Hz and 0.5 J/pulse). The EHL perforated at an average of 24.44 +/- 8.77 seconds and a total energy of 0.01 +/- 0 kJ. The CdL was able to perforate but at much longer intervals (257.51 +/- 99.08 seconds) and higher energy levels (12.88 +/- 4.95 kJ) on average than either the EHL or HoL. Lastly, the PI was unable to perforate the ureter in more than 6 continuous minutes of application. In addition, we found that at 2-mm separation between the HoL probe tip and the ureteral wall, acute perforation was not possible even at very high power settings. We conclude that although each endoscopic lithotripter has advantages as well as disadvantages, in this ex vivo model, it was clear that the HoL and EHL can easily perforate the ureter and must be used with vigilance. It was found that at 2 mm of separation between the probe and target, the HoL, was unable to perforate acutely. The CdL and PI were associated with a much higher safety index, and the PI was unable to produce ureteral perforation.

Acute Disease↗
PubMed1998

Hospitalization, inpatient physical therapy and institutionalization after hospital discharge of prostate cancer patients in south Florida.

PURPOSE: Explaining survival variation in prostate cancer requires the identification of new predictive factors, of which physical function is attractive hypothetically. To understand physical dysfunction in prostate cancer better, we examined medical claims. Our aims were to describe the consumption of inpatient resources, examine the association of physical therapy with institutionalization after hospital discharge and determine the association of disease stage with frequency of hospitalization, inpatient physical therapy and discharge to a skilled nursing facility. MATERIALS AND METHODS: We used 1994 Medicare claims for patients in South Florida who had prostate cancer. To examine the association of disease stage with use of health services, we inferred disease stage from stage specific treatment. Multiple linear regression was used to examine the interaction of inferred disease stage with health services while adjusting for age. RESULTS: A total of 22,279 residents of South Florida a mean of 78.3 years old with prostate cancer billed Medicare in 1994. Of these patients 2,507 were admitted to a hospital 4,606 times, resulting in total charges of $70 million. Many claims indicated physical dysfunction, including 1,896 charges for physical therapy, which was associated with more institutionalization after hospital discharge. Disease stage and patient age were individually associated with the frequency of hospitalization, inpatient physical therapy and discharge to a skilled nursing facility. CONCLUSIONS: Inpatients with prostate cancer have substantial stage dependent physical dysfunction. If the hypothesized interaction of physical dysfunction with mortality is confirmed in prospective studies and outpatient settings, theoretically the door will have been opened to new interventions for prolonging survival in patients with prostate cancer.

Aged↗
PubMed1998

The significance of changing trends in prostate cancer incidence and mortality.

The increasing incidence of prostate cancer stood for years as a seemingly unshakable axiom of modern medicine. Recent evidence illustrates that the incidence of prostate cancer may have peaked and raises questions about the relative meaning of prostate cancer in the future. This article reviews the many antagonistic factors that will affect prostate cancer incidence and mortality. No projections are offered about incidence and mortality, but it is believed that the number of patient-years with prostate cancer will increase and present new clinical challenges.

Humans↗
PubMed1997

Survival after radical prostatectomy.

CONTEXT: The generalizability of currently available estimates of survival after radical prostatectomy is theoretically limited. OBJECTIVE: To obtain generalizable estimates of survival after radical prostatectomy. DESIGN: A population-based retrospective cohort study. SETTING: Nine regions of the United States. PATIENTS: Patients who were diagnosed with prostate cancer between 1983 and 1987 and underwent radical prostatectomy and lymph node dissection. MAIN OUTCOME MEASURES: Proportional hazards models incorporating geographical region, age, race, pathological stage, lymph node involvement, and tumor grade to identify independent correlates of disease-specific and overall survival and life table analyses to estimate 10-year survival distributions. RESULTS: A total of 3626 patients with a mean age of 65 years were included in the study; 92.6% were white, 54.2% had moderate-grade cancer, 60.4% had no extension beyond the prostate, and 91.2% had no lymph node involvement. Using San Francisco-Oakland, Calif, as a reference region, no other region was significantly associated with a risk of disease-specific or overall mortality. Older age and black race were independently associated with worse overall but not disease-specific survival. Higher grade, extension beyond the prostate, and lymph node involvement were independently associated with worse disease-specific and overall survival. Estimates of 10-year disease-specific survival ranged from 75% to 97% for patients with well-differentiated and moderately differentiated cancers and from 60% to 86% for patients with poorly differentiated cancers. CONCLUSIONS: Neither disease-specific nor overall survival varied by region, suggesting geographically uniform assessments of risk in patient selection for radical prostatectomy. Across regions, overall survival varied by patient and prostate cancer characteristics while disease-specific survival varied substantially by prostate cancer but not patient characteristics. The present analyses provide the most generalizable current estimates of survival after radical prostatectomy.

Aged↗
PubMed1997

Endopeptidase 24.11 activity in the human prostate cancer cell lines LNCaP and PPC-1.

Human endopeptidase 24.11 (EP) occurs in greatest abundance on terminally differentiated prostate cells; thus, loss of EP could mark dedifferentiation of prostate epithelium. To identify laboratory models that would permit continuous work on the biochemistry and hormonal regulation of EP, we examined the well-differentiated LNCaP and poorly differentiated PPC-1 human prostate cancer cell lines. Ultrastructural analysis revealed that LNCaP secretes electron-dense material that resembles the particulate matter of seminal plasma, which is associated with endopeptidase activity. LNCaP medium contained EP activity while PPC-1 medium did not. Whether the apparent deletion of EP from the PPC-1 cell line is characteristic of poorly differentiated prostate adenocarcinoma is not yet clear. However, it may be relevant to the carcinogenic process that EP can limit growth of lung small carcinomas by inactivating cell growth-promoting bombesin-like peptides. Because bombesin has been identified in aggressive human prostate cancers, loss of EP in PPC-1 could represent a necessary step in transformation to aggressive phenotype. The combination of LNCaP and PPC-1, which offers well-differentiated and poorly differentiated cancer phenotypes, appears well suited to studying the relevance of EP in prostate cancer biology.

Adenocarcinoma↗
PubMed1997

Assessment of endpoints for clinical trials for localized prostate cancer.

OBJECTIVES: The AUA Practice Guidelines Panel convened to address the issue of appropriate endpoints for assessment of treatment modalities for localized carcinoma of the prostate. METHODS: A review of the literature and the design of existing clinical trials produced a consensus, which was presented to and critiqued by the members of the general conference. RESULTS: The pitfalls associated with identification of local failure endpoints were discussed, and the more accurate endpoints of freedom from metastatic progression and overall survival were recognized. The strict definition that must be fulfilled for intermediate endpoints to become surrogates for metastasis free and/or survival endpoints was stressed. For more efficient and rapid conduct of future clinical trials, the urgent need to validate such surrogate endpoints by evaluation in randomized control trials is obvious. PSA, while an indicator of disease activity and a critical marker for estimating disease progression or regression in response to therapy, is not a surrogate for metastasis free or overall survival. CONCLUSION: Until surrogate endpoints are validated, the committee has evaluated the endpoints in current use, reviewed their limitations, and stressed the importance of quality-of-life assessment together with the traditional endpoint assessment.

Clinical Trials as Topic↗