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Desmond Curran

Publications and source records attributed to Desmond Curran.

6 recordsLinked to original sources
PubMed2004

Retrospective analysis of results of p(65)+Be neutron therapy for treatment of prostate adenocarcinoma at the cyclotron of Louvain-la-Leuve. Part II: Side effects and their influence on quality of life measured with QLQ-C30 of EORTC.

PURPOSE: Between 1978 and 1998, 533 prostate adenocarcinoma patients were treated with mixed photon-neutron radiotherapy. We report on a retrospective series of patients for whom the side effects of the treatment and their impact on quality of life were assessed by a mailed questionnaire. METHODS AND MATERIALS: The European Organization for Research and Treatment of Cancer quality-of-life core questionnaire and a prostate-specific questionnaire were used. Between 1990 and 1996, 308 consecutive patients were treated. Two protocols were used: pelvic fields (50 Gy equivalent photons, 2 Gy/fraction) followed by a prostate boost (66 Gy) or prostate alone. The neutron/photon ratio varied. The questionnaire was mailed to 262 patients presumed to be alive. RESULTS: Of the 262 patients, 230 replied. Of the 230 patients, 73% had no trouble doing strenuous activities and 4% had trouble with taking a short walk. The overall physical condition and quality-of-life questions received a mean score of 5.2 and 5.3 on a 7-point scale, respectively. Twenty-two percent had bowel movements at least four times daily, and 6% did so six times or more. Retaining stool was a problem in 26%, and only 38% reported full continence; 17% urinated four times or more nightly. Urinary incontinence was scored as "quite a bit" or "very much" in 11% and 5%, respectively. Hematuria and dysuria (pain) were reported by 7% and 16%, respectively, mainly as moderate. Only 28% reported easy erections, but 75% judged the sexual change acceptable. A greater neutron/photon ratio was significantly associated with more bowel problems (p = 0.003). CONCLUSION: Mixed photon-neutron therapy for prostate cancer was associated with significant patient-reported side effects. Their significant effect on patients' quality of life is described.

Adenocarcinoma↗
PubMed2004

Sensitivity analysis for pattern mixture models.

Incomplete series of data is a common feature in quality-of-life studies, in particular in chronic diseases where attrition of patients is high. Two alternative approaches to modeling longitudinal data with incomplete measurements have frequently been proposed in the literature, selection models and pattern-mixture models. In this paper we focus on, by way of sensitivity analysis, extrapolating incomplete patterns using identifying restrictions. Perhaps the best known ones are so-called complete case missing value restrictions (CCMV), where for a given pattern, the conditional distribution of the missing data, given the observed data, is equated to its counterpart in the completers. Available case missing value (ACMV) restrictions equate this conditional density to the one calculated from the subgroup of all patterns for which all required components have been observed. Neighboring case missing value restrictions (NCMV) equate this conditional density to the one calculated from the the pattern with one additional measurement obtained. In this paper, these three identifying restriction strategies are used to multiply impute missing data in a study in metastatic prostate cancer. Multiple imputation is employed to reduce the uncertainty of single imputation. It is shown how hypothesis testing and sensitivity analyses are carried out in this setting.

Humans↗
PubMed2002

Multicollinearity in prognostic factor analyses using the EORTC QLQ-C30: identification and impact on model selection.

Clinical and quality of life (QL) variables from an EORTC clinical trial of first line chemotherapy in advanced breast cancer were used in a prognostic factor analysis of survival and response to chemotherapy. For response, different final multivariate models were obtained from forward and backward selection methods, suggesting a disconcerting instability. Quality of life was measured using the EORTC QLQ-C30 questionnaire completed by patients. Subscales on the questionnaire are known to be highly correlated, and therefore it was hypothesized that multicollinearity contributed to model instability. A correlation matrix indicated that global QL was highly correlated with 7 out of 11 variables. In a first attempt to explore multicollinearity, we used global QL as dependent variable in a regression model with other QL subscales as predictors. Afterwards, standard diagnostic tests for multicollinearity were performed. An exploratory principal components analysis and factor analysis of the QL subscales identified at most three important components and indicated that inclusion of global QL made minimal difference to the loadings on each component, suggesting that it is redundant in the model. In a second approach, we advocate a bootstrap technique to assess the stability of the models. Based on these analyses and since global QL exacerbates problems of multicollinearity, we therefore recommend that global QL be excluded from prognostic factor analyses using the QLQ-C30. The prognostic factor analysis was rerun without global QL in the model, and selected the same significant prognostic factors as before.

Antineoplastic Agents↗
PubMed2002

Prognostic factors for survival in adult patients with cerebral low-grade glioma.

PURPOSE: To identify prognostic factors for survival in adult patients with cerebral low-grade glioma (LGG), to derive a prognostic scoring system, and to validate results using an independent data set. PATIENTS AND METHODS: European Organization for Research and Treatment of Cancer (EORTC) trial 22844 and EORTC trial 22845 are the largest phase III trials ever carried out in adult patients with LGG. The trials were designed to investigate the dosage and timing of postoperative radiotherapy in LGG. Cox analysis was performed on 322 patients from EORTC trial 22844 (construction set), and the results were validated on 288 patients from trial 22845 (validation set). Patients with pilocytic astrocytomas were excluded from this prognostic factor analysis. RESULTS: Multivariate analysis on the construction set showed that age > or = 40 years, astrocytoma histology subtype, largest diameter of the tumor > or = 6 cm, tumor crossing the midline, and presence of neurologic deficit before surgery were unfavorable prognostic factors for survival. The total number of unfavorable factors present can be used to determine the prognostic score. Presence of up to two of these factors identifies the low-risk group, whereas a higher score identifies high-risk patients. The validity of the multivariate model and of the scoring system was confirmed in the validation set. CONCLUSION: In adult patients with LGG, older age, astrocytoma histology, presence of neurologic deficits before surgery, largest tumor diameter, and tumor crossing the midline were important prognostic factors for survival. These factors can be used to identify low-risk and high-risk patients.

Adult↗
PubMed2002

Strategies to fit pattern-mixture models.

Whereas most models for incomplete longitudinal data are formulated within the selection model framework, pattern-mixture models have gained considerable interest in recent years (Little, 1993, 1994). In this paper, we outline several strategies to fit pattern-mixture models, including the so-called identifying restrictions strategy. Multiple imputation is used to apply this strategy to realistic settings, such as quality-of-life data from a longitudinal study on metastatic breast cancer patients.

Journal Article↗