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  • accelerated failure time models  (1)
  • meta-analysis  (1)
  • 1
    Electronic Resource
    Electronic Resource
    An individual patient-based meta-analysis of tamoxifen versus ovarian ablation as first line endocrine therapy for premenopausal women with metastatic breast cancer (1997)
    Springer
    Breast cancer research and treatment 44 (1997), S. 201-210 
    Details
    ISSN: 1573-7217
    Keywords: metastatic breast cancer ; tamoxifen ; ovarian ablation ; randomized trial ; meta-analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed a meta-analysis of randomized trials comparing tamoxifen to ovarian ablation carried out either by surgery or irradiation as first-line hormonal therapy for pre-menopausal women with metastatic breast cancer. Patients in all trials included were required to have measurable disease and to be currently menstruating or within 1 year of cessation of menses, and to have estrogen receptor (ER) positive or unknown disease (ER negative women were admitted to one of the studies). Individual patient data were obtained from the four studies identified and the results updated to June 1992. A total of 220 eligible patients were enrolled in the four trials. There was no difference in overall response rate between tamoxifen and oophorectomy across the four trials (p = 0.94, Mantel-Haenszel test). The odds reduction for progression was 14% ± 12% and for mortality 6% ± 13% in favour of tamoxifen, results which were not statistically significant (p = 0.32 and 0.72, respectively). Although the design of all four studies included a cross-over to the other therapy, only 54/111 patients receiving ovarian ablation and 34/109 patients receiving tamoxifen as primary therapy actually crossed over to the other arm at the time of disease progression. Response to initial treatment with tamoxifen was predictive of subsequent response to ovarian ablation (p 〈 0.05), and response to initial therapy with ovarian ablation was predictive of subsequent response to tamoxifen (p 〈 0.05). Support curves based on log-likelihood ratios revealed that this meta-analysis provides moderate evidence rejecting a 14% advantage for ovarian ablation compared to tamoxifen in terms of odds of disease progression. A 25% advantage for ovarian ablation with respect to odds of death is also rejected with moderate evidence. We conclude that the efficacy of tamoxifen appears to be similar to that of ovarian ablation by surgery or irradiation as first-line therapy for premenopausal, ER positive metastatic breast cancer, and is unlikely to be substantially inferior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005833811584
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    A comparison of all-subset Cox and accelerated failure time models with Cox step-wise regression for node-positive breast cancer (1992)
    Springer
    Breast cancer research and treatment 22 (1992), S. 263-272 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; prognostic factors ; Cox regression ; all-subset regression ; accelerated failure time models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clinical studies usually employ Cox step-wise regression for multivariate investigations of prognostic factors. However, commercial packages now allow the consideration of accelerated failure time models (exponential, Weibull, log logistic, and log normal), if the underlying Cox assumption of proportional hazards is inappropriate. All-subset regressions are feasible for all these models. We studied a group of 378 node positive primary breast cancer patients accrued at the Henrietta Banting Breast Centre of Women's College Hospital, University of Toronto, between January 1, 1977, and December 31, 1986. 85% of these patients had complete prognostic factor data for multivariate analysis, and 96% of the patients were followed to 1990. There was evidence of marked departures from the proportional hazards assumption with two prognostic factors, number of positive nodes and adjuvant systemic therapy. The data strongly supported the log normal model. The all-subset regressions indicated that three models were similarly good. The variables 1) number of positive nodes, 2) tumour size, and 3) adjuvant systemic therapy were included in all three models along with one of three biochemical receptor variables 1) ER, 2) combined receptor (ER- PgR-; ER+ PgR-; ER- PgR+; ER+ PgR+; or 3) PgR. Better multivariate modeling was achieved by using quantitative prognostic factors, a check for appropriate underlying model-type, and all-subset variable selection. All-subset regressions should be considered for routine use with the many new prognostic factors currently under evaluation; it is very possible that there may not be a single model that is substantially better than others with the same number of variables.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01840839
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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