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PubMed1990

Statistical requirements of phase I studies.

Methodological aspects of planning and evaluating phase I studies in oncology--the link between preclinical research and approval of clinical efficacy--include the human starting dose, maximum tolerable dose and dose escalation schemes. Statistical requirements of phase I studies are presented here, emphasizing the urgency of their application in current practice. For the maximum tolerable dose a distinction will be made between an individual- and a population-based approach, which is crucial for a correct definition and statistical parameter estimation. Weaknesses of the dose escalation scheme according to the modified Fibonacci scheme are shown and contrasted with the recently proposed pharmacokinetically guided dose escalation. Comprehensive phase I/II information processing is recommended for validating current practice.

Antineoplastic Agents↗

PubMedDate not supplied

Statistical analysis of white blood cell data directed to the detection of malignancy in untreated patients.

A training set of 90 malignant cases (positives) and 61 non-malignant cases (negatives) was used to determine statistics for five parameters based on white blood cell analysis. The statistics used were thresholds, differences between the positive and negative means, and the weighted correlation matrix. Three decision methods using these statistics were then applied to a test set of 90 positives and 60 negatives. The percentage of correct decisions ranged from 98.67 per cent for parameter 3. The best result using only parameters capable of recognition by an automated apparatus was 94.00 per cent.

Cytodiagnosis↗

PubMed1988

Use of statistical evaluation of antigen profiles in differential diagnosis between colonic and ovarian adenocarcinomas.

A study was carried out to determine whether it was possible to classify colonic and ovarian adenocarcinomas by their antigen profile. Colonic and ovarian adenocarcinomas were immunostained with a panel of antibodies which have a limited specificity for colon (parlam-4, 19.9, anti-secretory component) and ovary (OV-TL3 and OC125) and the most discriminatory antibodies were selected by stepwise linear discriminant analysis. For frozen material OV-TL3 and OC125 were the best classifying antibodies. Although OC125 had better discriminative power, for paraffin wax embedded material parlam-4 was selected as the best classifying antibody. OC125 had no additional effect on the classification of a tumour. These antibodies were subsequently tested on an independent test set of primary and metastatic adenocarcinomas of colonic and ovarian origin. When ovarian posterior probabilities of less than 0.1 and greater than 0.9 were selected as cut off points for a positive identification of colonic or ovarian origin (jackknifed classification method), no adenocarcinoma was incorrectly identified as ovarian carcinoma in frozen material. The same trend was noticed for paraffin wax embedded material. Statistical analysis of antigen profiles can be helpful in defining the colonic or ovarian origin of an adenocarcinoma when routine microscopy does not yield a definitive result.

Adenocarcinoma↗

PubMed2006

Mucinous expression in benign and neoplastic glandular lesions of the uterine cervix.

CONTEXT: Mucins are glycoproteins produced by both normal and neoplastic glandular epithelial cells including endocervix. OBJECTIVE: To determine the expression of mucins in uterine cervical glandular lesions and whether mucin expression correlates with the nature and origin of the glandular lesions. DESIGN: Antibodies to MUC1, MUC2, MUC4, and MUC5AC were applied on 52 cases including 14 endocervical adenocarcinomas (including 4 adenosquamous carcinomas), 9 endometrial carcinomas (8 endometrioid adenocarcinomas and 1 adenosquamous carcinoma), 8 adenocarcinoma in situ (AIS), 2 glandular dysplasias, 6 tubal metaplasias, 10 microglandular hyperplasias, and 3 normal endocervix. The presence of any staining was considered positive. RESULTS: All benign endocervical epithelia, including tubal metaplasia and microglandular hyperplasia, expressed MUC1, MUC4, and MUC5AC but not MUC2. Almost all endocervical AIS and carcinomas and all endometrial adenocarcinomas expressed MUC1; the exceptions were 2 cases of endocervical adenocarcinoma and 1 case of adenosquamous carcinoma of the endocervix. MUC2 staining was noted in 25%, 40%, and 22% of AIS, endocervical adenocarcinomas, and endometrial adenocarcinomas, respectively. About 38% of AIS, 75% of endocervical adenocarcinomas, and 44% of endometrial adenocarcinomas expressed MUC4. Half of AIS, most of endocervical adenocarcinomas, and 22% of endometrial adenocarcinomas expressed MUC5AC. The difference in MUC4 and MUC5AC expression between benign endocervical lesions and AIS and the difference in MUC5AC expression between endocervical and endometrial neoplasms were statistically significant. CONCLUSIONS: Mucin expressions differed among benign endocervical lesions and AIS and among endocervical and endometrial malignancies. These results suggest that mucin staining may potentially be helpful in differentiating various uterine cervical glandular lesions.

Adenocarcinoma↗

PubMed1985

Flash and pattern presentation and pattern-reversal evoked potentials in multiple sclerosis.

The visual evoked potential (VEP) results for 404 multiple sclerosis (MS) patients are presented. In 171 patients pattern reversal with light-emitting diode (PR (LED] VEPs and in 85 patients pattern reversal with TV (PR(TV] VEPs also were investigated. The pathologic process of MS affects the amplitude and latency of all components and the form and symmetry of responses. A complex evaluation of VEP is proposed instead of measurement of only one component. A combined flash and pattern presentation VEP evaluation may be as effective as PREPs in the detection of subclinical lesions. PR(LED) VEP seems to be more sensitive to the degree of visual disturbance and to the clinical probability of MS than the PR(TV) VEP. A statistical analysis disclosed correlation of VEP amplitude and latency data with the visual impairment, one with the duration and multiplicity (generalization) of the disease. Combination of different methods increases the discriminative power of the VEP investigation.

Adult↗

PubMed1984

The use of three baseline values in intervention studies: application to evaluation of immune modulation therapies.

In studying the effects of a treatment intervention on immunological parameters, we have found that three baseline values are a practical number to obtain on each patient. Three baseline values 1) increase the chances of detecting a statistically significant effect of the intervention, 2) provide an assessment of the daily variability of the assay and patients, and 3) enable the identification of individual patients who demonstrate significant changes associated with the intervention.

Drug Evaluation↗

PubMed2005

Maspin overexpression modulates tumor cell apoptosis through the regulation of Bcl-2 family proteins.

BACKGROUND: Maspin is a member of serpin family with tumor suppressing activity. Recent studies of maspin in animal models strongly support maspin's role as an inhibitor against the growth of primary tumor sand the process of metastasis. However, the molecular mechanism underlying this inhibition has not been fully elucidated. In this report, we analyze the effect of maspin on tumor cell apoptosis under several stress conditions. METHODS: Stable clones overexpressing maspin are established in the mouse mammary tumor TM40D cells. They are treated with staurosporine, TNF-alpha, and serum starvation. The rates of cell apoptosis are analyzed by TUNEL assay. Inhibitors against caspase 8 and 9 are used in the apoptosis assay. Western blot analysis and ribonuclease protection assay (RPA) are performed to examine the expression of Bcl2 family genes. RESULTS: We report that maspin expressing tumor cells have increased rate of apoptosis when they are treated with staurosporine and serum starvation. The effect is not through extracellular maspin. Maspin-mediated apoptosis is partially blocked by caspase 8 and 9 inhibitors, and is accompanied by changes in the Bcl-2 family proteins. Maspin-expressing tumor cells have a reduced level of anti-apoptotic protein Bcl-2, and an increased level of pro-apoptotic protein Bax. The regulation is not controlled at the transcriptional level but is through selective control of Bcl-2 and Bax protein stability. CONCLUSION: Maspin overexpression modulates tumor cell apoptosis through the regulation of Bcl2 family proteins. Such change results in an increased release of cytochrome c from mitochondria, thus the increased apoptosis in maspin-expressing cells. This evidence strongly suggests that the induction of apoptosis in maspin-overexpressing cells represents a major mechanism by which maspin inhibits breast tumor progression.

Animals↗

PubMed1988

Prognostic significance of DNA aneuploidy in stage I cutaneous melanoma.

The prognostic significance of DNA aneuploidy was studied restrospectively in 177 Stage I cutaneous melanomas. DNA content was determined by flow cytometry of propidium iodide-stained nuclei recovered from formalin-fixed, paraffin-embedded material. Of 162 evaluable histograms, 124 were diploid, 35 aneuploid, and 3 tetraploid. Aneuploidy strongly correlated with established predictors of unfavorable prognosis, namely, thickness p less than .005, level p less than 0.005, ulceration p less than 0.005, and presence of vertical growth phase p less than 0.02. Overall, aneuploidy was strongly correlated with recurrence (p less than 0.005) and shorter disease-free survival (p less than 0.0001). Aneuploidy was an independent predictor of recurrence for tumors less than 1.5 mm thick (p less than 0.0001) and greater than or equal to 3 mm thick (p = 0.031). For melanomas 1.5-2.9 mm thick, aneuploid tumors had a 27% higher recurrence rate than diploid tumors (63% vs. 36%). This was not statistically significant (p = 0.247). In a multivariate analysis of common predictors stratified by thickness, DNA aneuploidy was the most significant independent parameter (p less than 0.002). DNA content appears to be an important stratification parameter for Stage I cutaneous melanoma.

Actuarial Analysis↗

PubMed1996

Is the percentage of cancer in biopsy cores predictive of extracapsular disease in T1-T2 prostate carcinoma?

BACKGROUND: Information regarding the quantity of biopsy material invaded by cancer may supplement the usual criteria for the preoperative staging of patients suffering from clinically localized prostate carcinoma (T1-T2). However, conflicting conclusions have been drawn and this topic needs further investigation. METHODS: A total of 170 patients had radical prostatectomy for T1-T2 prostate carcinoma. Patients' mean age (+/- standard deviation [SD]) was 66.05 +/- 6.12 years and mean prostate specific antigen (PSA) level (+/- SD) was 22.5 +/- 21.4 ng/mL (Yang Proscheck). Of the patients, 110 underwent transrectal ultrasound-guided biopsy with removal of 6 cores, from whom we had the percentage of biopsy, material invaded by cancer, the Gleason score, and the preoperative PSA. These parameters were compared with the pathologic features of the surgical specimen (capsule penetration, surgical margins, and Gleason score) and biologic progression (defined as persistent/recurrent postoperative PSA > 0.1 ng/mL). RESULTS: The most valid threshold of biopsy material invaded by cancer for predicting surgical margins and capsule status, as well as biologic progression, was 10%. When < 10% of biopsy material was invaded by cancer, positive surgical margins (SM+) were present in 30.3%, capsular penetration (pT3, pathologic extracapsular involvement) in 27.3%, and biologic progression (P+) in 21.7%. The Gleason score did not improve this prognostic evaluation. The mean quantities of tissue invaded by cancer differed significantly between positive and negative surgical margin groups, between pT2 and pT3 groups, and between P- and P+ groups (no biologic progression/biologic progression). There was statistical significance (log rank test, P = 0.0320 in the survival without biologic postoperative progression between patients with < or = or > 10% of one core biopsy invaded by tumor. If < or = 10% of tissue in only 1 of 6 cores of a biopsy was invaded by tumor, the status was pT2, SM-, and P- in 87.5% of the patients. CONCLUSIONS: On an individual basis, the percent of tissue containing carcinoma in core biopsies was a factor that lacked the statistical power to predict the status of the capsule and surgical margins, and the biologic progression. The finding of < or = 10% of carcinoma in 1 of 6 cores of a biopsy was correlated with a good prognosis.

Adult↗

PubMed2005

Metallothionein expression in benign and malignant canine mammary gland tumours.

The presence of metallothioneins (MTs) were demonstrated immunohistochemically using a monoclonal antibody (E9) against a conserved epitope of I and II isoforms in canine mammary tumours. In a semiquantitative analysis MT expression in the tumour cells was observed in 54/54 cases of benign and 32/40 malignant mammary neoplasms. A statistically significant difference at the level of P<0.01 was observed for MT expression between benign and malign mammary tumours in terms of immunoreactivity score. It is concluded that immunohistochemically demonstrated MT expression is significantly associated with benign canine mammary tumours.

Animals↗

PubMed1980

[Epidemiological and clinical aspects of malignant tumors of the mouth mucosa].

Any statement regarding the frequency of cancer in the Federal Republic of Germany must be based on the mortality index. Data on the frequency of malignant tumors of the oral mucosa were collected and compared with the international statistics. The focus of the DOSAK study (German-Austrian-Swiss study group for tumors of the maxillofacial region0, which has concerned itself with epidermiologic and clinical studies since 1966, was discussed. Retrospective studies of documentation and prospective studies of therapy for carcinoma of the oral mucosa were discussed in particular.

Austria↗

PubMed2003

Radiotherapy alone for primary Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma is a rare and potentially aggressive cancer of the skin. Cumulative data from small retrospective series have supported treatment by wide excision and adjuvant radiotherapy. However, wide excision may be difficult to perform in patients with tumors of the head and neck or in older populations with comorbidities that may be incompatible with general anesthesia. OBSERVATIONS: Nine patients (group 1) with stage I (without lymph node involvement) Merkel cell carcinoma primary tumors were treated in our center by radiotherapy alone. The rate of recurrence was compared between this group and 17 additional patients (group 2) with stage I Merkel cell carcinoma who received conventional treatment (surgery followed by radiotherapy). RESULTS: The median follow-up was 3.0 years (range, 8 months to 7 years) for group 1 and 4.6 years (range, 5 months to 11 years) for group 2. During this period, we observed 1 relapse and 1 progression of disease in group 2. No statistical difference was found in overall and disease-free survival between the 2 groups of patients. CONCLUSION: This study demonstrates the possibility of treating inoperable Merkel cell carcinoma by radiotherapy alone, with outcomes similar to those of classic treatment.

Aged↗

PubMed1985

Multivariate cohort analysis.

Modern methods of categorical and survival data analysis are usefully applied to the multivariate analysis of follow-up data that arise in epidemiologic cohort studies. They provide a formal basis for extending analyses based on the standardized mortality ratio into the multivariate domain so as to permit simultaneous consideration of such risk factors as age, duration, and intensity of exposure; age and calendar year of follow-up; and personal characteristics. Analogous methods are available that control for demographic variables internally, without reference to vital statistics or other standard rates. Various model structures allow for the effects of different variables to combine in an additive, multiplicative, or mixed (additive relative risks) fashion. Illustrative analyses are provided of the relationship between respiratory cancer mortality and arsenic exposure in a cohort of Montana smelter workers.

Arsenic↗

PubMed1989

Sample sizes for constructing confidence intervals and testing hypotheses.

Although estimation and confidence intervals have become popular alternatives to hypothesis testing and p-values, statisticians usually determine sample sizes for randomized clinical trials by controlling the power of a statistical test at an appropriate alternative, even those statisticians who recommend the use of confidence intervals for inference. There is merit in achieving consistency in the techniques for data analysis and sample size determination. To that end, this paper compares sample size determination with use of the length of the confidence interval with that obtained by control of power.

Angina Pectoris↗

PubMed2006

Selective immunohistochemical comparison of polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma.

PURPOSE: Polymorphous low-grade adenocarcinoma (PLGA) is a salivary gland malignancy characterized by indolent growth and a low rate of metastasis. PLGA shares histological features with adenoid cystic carcinoma (ACC), including infiltrating solid and cribriform patterns, presence of cystic spaces, and neurotropism. The degree of polymorphism of PLGA presents diagnostic challenges, particularly in small biopsy specimens. Immunohistochemical reactions to differentiate PLGA from the more aggressive ACC would be extremely valuable but controversy exists in the current literature regarding their utility. This study examines the potential use of c-kit, Ki-67, smooth muscle actin (SMA), and muscle-specific actin (MSA) as ancillary markers for distinguishing PLGA from ACC. PATIENTS AND METHODS: Medical records of 20 cases of PLGA treated at the Massachusetts General Hospital were reviewed. Patient demographic data and tumor-specific information were elicited. Formalin-fixed paraffin-embedded sections from 10 of these cases and 12 comparison cases of ACC were accessed. The histologic diagnoses were confirmed and immunohistochemical staining using antibodies to c-kit, Ki-67, SMA, and MSA was employed to determine differences in staining. RESULTS: PLGA showed a significantly weaker immunohistochemical expression of c-kit compared with ACC (P = < .001). Ki-67, correlating with proliferative behavior, was more weakly expressed in PLGA (P = .091). The exuberant myoepithelial component of ACC resulted in stronger staining with SMA and MSA (P = .047; P = .065, respectively). CONCLUSIONS: Statistically significant immunohistochemical staining patterns using c-kit and SMA in this study support their potential use as markers to differentiate PLGA from ACC in cases where the diagnosis can be challenging.

Actins↗

PubMed1977

Assessment of inherent fluctuations of mitotic and labelling indices of human tumours.

A method is presented to evaluate the influence of statistical errors and inherent variation on the determination of mitotic and labelling indices of human tumours. In most of the experiments reported here, sufficient cells were counted to yield a statistical error which is small in comparison to the inherent differences in the proliferative indices, both between different sites in the same tumour and between different tumours of the same histological type. These inherent fluctuations are, theefore, a critical factor in cell kinetic studies of human tumours.

Cell Count↗

PubMed2005

A nonparametric comparison of conditional distributions with nonnegligible cure fractions.

Survival data with nonnegligible cure fractions are commonly encountered in clinical cancer clinical research. Recently, several authors (e.g. Kuk and Chen, Biometrika 79 (1992) 531; Maller and Zhou, Journal of Applied Probability, 30 (1993) 602; Peng and Dear, Biometrics, 56 (2000) 237; Sy and Taylor, Biometrics 56 (2000) 227) have proposed to use semiparametric cure models to analyze such data. Much of the existing work has been emphasized on cure detections and regression techniques. In contrast, this project focuses on the hypothesis testing in the presence of a cure fraction. Specifically, our interest lies in detecting whether there exists survival differences among noncured patients between treatment arms. For this purpose, we investigate the use of a modified Cramér-von Mises statistic for two-sample survival comparisons within the framework of cure models. Such a test has been studied by Tamura et al., (Statistics in Medicine 19, 2000, 2169) using bootstrap procedure. We will focus on developing asymptotic theory and convergent algorithms in this paper. We show that the limiting distributions of the Cramér-von Mises statistic under the null hypothesis can be represented by stochastic integrals and a weighted noncentral chi-squares. Both representations lead to concrete numerical schemes for computing the limiting distributions. The algorithms can be easily implemented for data analysis and significantly reduce computing time compared to the bootstrap approach. For illustrative purposes, we apply the proposed test to a published clinical trial.

Algorithms↗

PubMed2005

A pilot study on the frequency structure of histological neoplasm diagnoses in rats.

There are large differences in the frequencies of different kinds of neoplasms in a human or animal population. The question arises, whether the set of these frequencies shows some characteristic feature. Our fitting results on neoplasm frequency data relating to laboratory rats show that the frequencies are approximately lognormally distributed. At the same time, fitting results with the logarithmic series distribution, also frequently used in similar studies, are poor. A good fit of the Zipf-Mandelbrot distribution, fitted to the descendingly ordered dominant and subdominant frequencies can be achieved, sometimes after omitting some diagnoses. We point out the possibility that the omitted frequencies may be considered "unnatural" ones. The good fit of a particular frequency distribution to the diagnosis frequency set suggests a corresponding chance mechanism in forming the occurrence probabilities of different kinds of neoplasms. A frequently used scalar feature of frequency distributions of categorical data is the concentration or diversity. It was found that in the female rat population the diagnoses are more concentrated among the diagnosis categories. A possible explanation may involve the fact that females mature faster than males. The study of the distribution properties of the diagnosis frequencies promises the observation of new epidemiological phenomena.

Animals↗