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Elena Miravalles

Publications and source records attributed to Elena Miravalles.

7 recordsLinked to original sources
PubMed2006

Extent of prostate-specific antigen contamination in the Spanish section of the European Randomized Study of Screening for Prostate Cancer (ERSPC).

OBJECTIVES: The performance of tests outside prostate cancer screening trials (PSA contamination) may affect their statistical power. The present study addressed the extent of PSA contamination in the Spanish section of the European Randomized Study of Screening for Prostate Cancer (ERSPC) and its impact on biopsy performance and prostate cancer detection. METHODS: Data linkage was performed to address screening-related interventions outside the study. Four databases were used: (1) Spanish ERSPC database (n=4278), (2) laboratory database with all PSA determinations (n=31,140), (3) database of 1608 prostate biopsies, and (4) records of all prostate cancers (n=819) diagnosed at our centre. PSA contamination, biopsy performance, and cancer detection rates were calculated. RESULTS: Median follow-up time was 6.6 yr. A total of 2201 PSA determinations were performed for 1253 men. Cumulative PSA contamination was 29.3% (17% in the control arm during the first 4 yr). A higher proportion of men undergoing biopsies was found in the screening arm (21.3% vs. 2.9% in the control arm, p<0.0001). Similarly, higher cancer detection rates were found in the screening (4.7% vs. 1.2% in the control arm, p<0.0001). CONCLUSIONS: In our experience, the PSA contamination rate has increased during the last years, but its impact on biopsy performance and cancer detection in the control arm of the trial is limited and not likely to compromise the statistical power of the ERSPC trial.

Aged↗
PubMed2005

The predictive power of serum kappa/lambda ratios for discrimination between monoclonal gammopathy of undetermined significance and multiple myeloma.

The predictive power of serum kappa/lambda ratios on initial presentation of immunoglobulin G (IgG) or IgA monoclonal component was studied to differentiate between monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) patients. The retrospective study involved 145 patients clinically diagnosed with monoclonal gammopathy of undetermined significance or multiple myeloma, who had serum M-protein IgG <35 g/L or IgA <20 g/L at M-protein detection. Serum light chains kappa and lambda were measured by fixed-time nephelometry. Test performance indices, predictive values and likelihood ratios were calculated according to the Weissler recommendation. MM patients were considered as diseased and MGUS patients as non-diseased in order to estimate the performance characteristics of serum kappa/lambda ratios. There was a statistically significant difference in kappa/lambda ratios distribution between both groups of patients, in both M-protein kappa-type (Mann-Whitney U=168, p<0.001) and in M-protein lambda-type (Mann-Whitney U=143, p<0.001). Negative likelihood ratios at threshold levels of 0.6 and 4.2 were 2.17- and 3.32-fold greater, respectively, than positive likelihood ratios, so that the predictive power of a serum kappa/lambda ratio within these limits is better in ruling out (negative predictive power) than ruling in disease (positive predictive power). The post-test characteristics of a serum kappa/lambda ratio interval between 0.6 and 4.2 in discriminating MGUS from MM in our geographic population were: sensitivity 0.96 (0.93-0.99 95% CI); specificity 0.70 (0.63-0.77); positive predictive value 0.68 (0.64-0.73); negative predictive value 0.96 (0.94-0.99); likelihood ratios (+)LR 3.23 (2.68-4.04); and (-)LR 17.16 (11.00-63.00). Thus, serum M-protein with a kappa/lambda ratio between 0.6 and 4.2 increases the posterior probability of MGUS from 0.60 to 0.96 in asymptomatic patients, for whom only monitoring may be suggested when the serum kappa/lambda ratio is within these limits.

Adult↗
PubMed2005

Linearity and detection limit in the measurement of serum M-protein with the capillary zone electrophoresis system Capillarys.

We studied the linearity and detection limits of the capillary zone electrophoresis system Capillarys in the measurement of serum monoclonal protein. Three monoclonal proteins with different isotypes and electrophoretic migrations were diluted with a hypo-gamma-globulinemic polyclonal serum pool. Mathematical linearity was observed for all monoclonal protein isotypes in the ranges studied without removing the polyclonal gamma-globulin background. Theoretical concentrations of 0.43, 0.89 and 0.33 g/L for monoclonal proteins immunoglobulin (Ig)G, IgA and IgM, respectively, gave a discernible spike by Capillarys, although they were measured as 0.76, 1.09 and 0.76g/L, respectively. We observed overestimation of monoclonal protein inversely correlated to concentrations below 15 g/L. All these limitations have to be taken into account when monitoring monoclonal proteins, because the loss of linearity and the protein background may hide an increase in concentration at low levels.

Blood Protein Electrophoresis↗
PubMed2004

Prostate cancer detection is also relevant in low prostate specific antigen ranges.

OBJECTIVE: To address detection rates and clinical features of the cancers detected with low prostate specific antigen (PSA) levels. METHODS: In the context of a prostate cancer (PCa) screening program 1097 men attended to a new rescreen round. Sextant prostate biopsy was recommended when PSA > or =3 ng/ml. We also recommended to undergo biopsy in the range 1.0-2.99 ng/ml when free to total (f/t) PSA ratio < or =20%. Detection rate was calculated and clinical features of the cancers detected were studied. RESULTS: Mean age was 61.1 years. A total of 497 (45.3%) had total PSA <1.0 ng/ml, 439 (40%) between 1.0 and 2.99 ng/ml, and 161 (14.7%) > or =3.0 ng/ml. In the group with PSA between 1.0 and 2.99 ng/ml and f/t PSA ratio < or =20% a total of 249 biopsies were indicated (159 performed, acceptance 63.9%), and 15 cancers detected (detection rate 9.4%). Biopsy was recommended to 72 men with PSA between 3.0 and 3.99 ng/ml, performed in 56 (77.8%), and 12 tumors detected (detection rate 21.4%). All cancers in the study were clinically localized. Only 4 out of 15 cancers with PSA in the range 1.0-2.99 ng/ml (26.7%) fulfilled clinical criteria of insignificant cancer. Two were poorly differentiated and found to have patologically extracapsular disease. None of the 12 patients with PCa and PSA between 3.0 and 3.99 ng/ml had poorly differentiated features and only one complied with criteria of insignificant cancer. One out of seven who underwent RRP was found to have extracapsular disease. CONCLUSIONS: Cancer detection in low PSA ranges is lower but still relevant. The detection of potentially aggresive cancers is still of concern.

Aged↗
PubMed2002

PSA-use in a Spanish industrial area.

OBJECTIVES: To document the extent of prostate-specific antigen (PSA)-testing in the general population at Getafe (Spain) outside our prostate cancer (PC) screening program, and to check its performance in terms of PC detection. METHODS: A total of 5371 PSA-test records (1997-1999) were reviewed and testing rates estimated per 1000 person-years. The extent of patient referral (men referred to our facilities) was calculated adjusting for PSA levels. To approach the performance of testing in the general population, our PC screening program acted as a standard for comparison. The probability of missing one PC in the general population was estimated in terms of number of men necessary to screen (NNS). Calculations were made adjusting for PSA levels. RESULTS: PSA-testing rate in the general population was 21.6/1000 person-years. In the age-group 55-69 years, this rate was 86.8/1000 (152.6 in men >70 years). Referral rates were 67.9 and 39.5% for men with PSA 4-10 and >10 ng/ml, respectively. Overall PC detection rate was 1.76%. Detection rates for PSA 4-10 and >10 ng/ml were 4.66 and 12.94%, respectively. When compared with the performance of the screening program, for every 17 men with a PSA in the range 4-10 ng/ml one cancer was missed (95% confidence interval (CI), 9-580). Similarly, one cancer was lost for every four men with a PSA >10 ng/ml (95% CI, 2-8). CONCLUSIONS: The extent of opportunistic testing in our setting is very high, particularly in the older age groups. Opportunistic screening renders PC detection rates lower than expected for every PSA level and cannot be encouraged.

Age Factors↗
PubMed2002

Classification of renal proteinuria: a simple algorithm.

Total protein, albumin, alpha1-microglobulin, and immunoglobulin G (IgG) were analyzed in 1,622 urine samples without Bence-Jones proteinuria or gross hematuria. There was correlation with the histological picture obtained on renal biopsy in 61 patients. We established 24-h reference intervals for alpha1-microglobulin and IgG on 659 urine samples with total protein and albumin excretion rates below 100 mg/24 h and 30 mg/24 h, respectively, and creatinine clearance above 80 ml/min. The central 95% reference interval was found to be between 4 and 17 mg/24 h for alpha1-microglobulin and between 3 and 8.5 mg/24 h for IgG. In 80 urine samples with albumin excretion rate above 30 mg/24 h and alpha1-microglobulin and IgG within their reference intervals, we analyzed the 95% central interval of the distribution of the IgG/albumin ratios, and it was found to be within 0.01 and 0.20 (0.90 confidence interval: 0.17-0.24). Proteinuria was considered to be of the selective glomerular type if the albumin excretion rate was abnormal and the IgG/albumin ratio was under 0.20, even when the IgG excretion was within a pathological range. For the classification of proteinuria as predominantly tubular, we estimated the alpha1-microglobulin/albumin ratio in 173 urine samples with normal excretion rates of albumin and IgG and pathological excretion of alpha1-microglobulin. The discriminating value of 0.91 (0.90 confidence interval: 0.78-1.08) was accepted in order to define proteinuria of a tubular origin in the presence of a pathological albumin excretion rate. The association between albumin and IgG excretion rates and tubular reabsorption of the alpha1-microglobulin normally filtered by the glomerulus was studied in 33 urine samples from patients with no histologically significant tubulo-interstitial or vascular disease and a serum creatinine concentration below 141 pmol/l. The optimal curve-fitting function between albumin plus IgG and alpha1-microglobulin excretion rates was of the quadratic type (r = 0.927). Mixed proteinuria was considered when both, albumin and alpha1-microglobulin excretion rates were pathological and could not be included in the previously described groups.

Algorithms↗