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Recursive Partitioning Analysis (recursive + partitioning_analysis)
Selected AbstractsMolecular determinants of irinotecan efficacyINTERNATIONAL JOURNAL OF CANCER, Issue 10 2006Daniel Vallböhmer Abstract Molecular markers predicting the efficacy of CPT-11 based chemotherapies in patients with colorectal cancer (CRC) are unknown. Therefore, we investigated whether mRNA levels of drug targets (Topoisomerase I, TS), enzymes involved in 5-FU metabolism (DPD), in angiogenesis (EGFR, IL-8, VEGF) and in DNA-repair/drug detoxification (ERCC1, GST-P1) are associated with the clinical outcome of patients with CRC treated with first-line CPT-11 based chemotherapy. Thirty three patients with metastatic CRC were included in the study. Intratumoral gene expression levels were assessed from paraffin-embedded tissue samples, using laser capture microdissection and quantitative Real-Time PCR. Complete response was observed in 1 patient, partial response in 12 patients, stable disease in 13 patients and progressive disease in 6 patients. Response was inevaluable for 1 patient. Patients with complete response or partial response were classified as responders, while patients with stable disease or progressive disease were classified as nonresponders. High intratumoral mRNA levels of EGFR, ERCC1 and GSPT-P1 were each significantly associated with response to CPT-11 based chemotherapy. Recursive partitioning analysis showed that mRNA levels of EGFR and ERCC1 are primarily responsible for delineating responders from nonresponders. Also, the combination of high intratumoral gene expression levels of both EGFR and ERCC1 was significantly associated with progression-free survival. The mRNA levels of EGFR had a significant correlation with expression levels of ERCC1, GST-P1 and VEGF. This small retrospective study suggests that gene expression levels of EGFR, ERCC1 and GST-P1 may be useful in predicting the clinical outcome of patients with metastatic CRC treated with first-line CPT-11 based chemotherapy. © 2006 Wiley-Liss, Inc. [source] External validation of a risk group defined by recursive partitioning analysis in patients with head and neck carcinoma treated with surgery and postoperative radiotherapyHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 9 2007Xavier León MD Abstract Background: Several clinical trials have proved that concurrent chemoradiotherapy is more efficacious than radiotherapy alone among high-risk patients with head and neck squamous cell carcinoma (HNSCC) who undergo surgery. A risk-group classification defined according to a recursive partitioning analysis (RPA) for these patients has been recently proposed. The objective of the present study was to carry out an external validation of this RPA-derived classification system. Methods: A retrospective study of 442 HNSCC patients treated with surgery and postoperative radiotherapy was conducted. The external validity of the RPA-derived classification system was assessed, and its ability to stage patients and to predict locoregional control of the disease was compared with the TNM system. Results: The RPA-derived classification system succeeded in obtaining a monotonic prognosis gradient in locoregional control of the disease with increasing stage, and achieved greater differences in survival between stages than the TNM and pTNM classifications. Besides, the RPA method had a better homogeneity of the categories included in each stage, and in the heterogeneity between stages. Conclusions: The RPA-derived classification system allowed for the clear definition of prognostic groups in surgically treated HNSCC patients, improving the prognostic capacity of the TNM and pTNM classifications. The RPA-derived classification system is a useful tool in the definition of patients who, given a poor prognosis, should be considered candidates to adjuvant chemoradiotherapy. © 2007 Wiley Periodicals, Inc. Head Neck, 2007 [source] Identification and significance of sources of spatial variation in grapevine water statusAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2010J.A. TAYLOR Abstract Background and Aims:, Water stress in grapevines is directly linked to grape quality. Differential vine water management should therefore be strongly linked to the water stress in the vine. To do this, an understanding of the dominant drivers and indicators of vine water status are needed from a sub-block to whole vineyard level. This understanding will help generate effective vine water status models for variable rate irrigation systems. Methods and Results:, A vineyard in the south of France was sampled for pre-dawn leaf water potential (,PD) at several dates during the growing season for two consecutive years. Sampling was stratified by soil types and relative within-block vegetative expression. A recursive partitioning analysis identified that cultivar had a dominant effect at low water stress, while vegetative expression and then soil unit effects became dominant as water restriction increased. Variance in ,PD was calculated at difference scales (plant, site, block and vineyard) and Smith's heterogeneity law was used to evaluate the scalar nature of ,PD variance. Spatial heterogeneity increased as the season and water restriction increased. Conclusion:, Variance in ,PD changed temporally through a season and the dominant drivers/indicators also changed. The opportunity to spatially manage water stress (irrigation) increased as water restriction increased. Significance of the Study:, Managing vine water stress helps optimise production and a ,PD model would be a useful addition to a viticulture decision support system. This study identified how the variance in ,PD evolved during a season and the best ancillary indicators of ,PD for spatial and temporal modelling. [source] Whole-brain radiotherapy versus stereotactic radiosurgery for patients in recursive partitioning analysis classes 1 and 2 with 1 to 3 brain metastasesCANCER, Issue 10 2007Dirk Rades MD Abstract BACKGROUND. The authors investigated whether stereotactic radiosurgery (SRS) alone improved outcomes for patients in recursive partitioning analysis (RPA) Classes 1 and 2 who had 1 to 3 brain metastases compared with whole-brain radiotherapy (WBRT). METHODS. Data regarding 186 patients in RPA Classes 1 and 2 who had 1 to 3 brain metastases and who received either 30 to 40 grays (Gy) of WBRT (n = 91 patients) or 18 to 25 Gy SRS (n = 95 patients) were analyzed retrospectively. Eight other potential prognostic factors were evaluated regarding overall survival (OS), entire brain control (BC), local control (LC) of treated metastases, and brain control distant from treated metastases (distant control [DC]): Those 8 factors were age, sex, performance status, tumor type, number of brain metastases, extracranial metastases, RPA class, and interval from tumor diagnosis to radiotherapy. RESULTS. On multivariate analysis of OS, age ( risk ratio [RR], 1.51; P = .024), Karnofsky performance status (KPS) (RR, 1.98; P = .002), and extracranial metastases (RR, 2.26; P < .001) were significant, whereas the radiation regimen was not significant (P = .89). On multivariate analysis of BC, only the radiation regimen (RR, 1.33; P = .003) was found to be significant. On multivariate analysis of LC, radiation regimen (RR, 1.63; P < .001) and sex (RR, 1.62; P = .022) were significant. On multivariate analysis of DC, KPS (RR, 1.85; P = .049) and extracranial metastases (RR, 1.69; P = .047) were significant. The radiation regimen was not found to be significant even on univariate analysis (P = .80). In RPA class subgroup analyses, BC and LC were better after SRS than WBRT for patients in RPA Classes 1 and 2, whereas OS and DC did not differ significantly. CONCLUSIONS. For patients in RPA Classes 1 and 2 who had 1 to 3 brain metastases, SRS alone was associated with improved BC and LC compared with 30 to 40 Gy WBRT, whereas OS and DC were not significantly different. Similar results were observed in separate subgroup analyses of patients in RPA Class 1 and RPA Class 2. Cancer 2007. © 2007 American Cancer Society. [source] A boost in addition to whole-brain radiotherapy improves patient outcome after resection of 1 or 2 brain metastases in recursive partitioning analysis class 1 and 2 patientsCANCER, Issue 7 2007Dirk Rades MD Abstract BACKGROUND. The current study was conducted to compare 2 treatment regimens including surgical resection and whole-brain radiotherapy (WBRT) for patients with 1 to 2 brain metastases. METHODS. A total of 201 patients with recursive partitioning analysis (RPA) class 1 to 2 disease with 1 to 2 resectable brain metastases were analyzed retrospectively. Patients underwent either resection of the metastases plus WBRT with 10 fractions of 3 grays (Gy) each or 20 fractions of 2 Gy each (99 patients; Group A) or the same treatment plus a WBRT boost to the metastatic site (10 fractions of 3 Gy each plus 5 fractions of 3 Gy each or 20 fractions of 2 Gy each plus 5 fractions of 2 Gy each) (102 patients; Group B). Eight other potential prognostic factors were evaluated with regard to overall survival (OS), brain control (BC), and local control of resected metastases (LC): age, gender, Karnofsky performance status, extent of surgical resection, tumor type, extracranial metastases, RPA class, and interval from tumor diagnosis to WBRT. RESULTS. Group B patients had better 1-year OS (66% vs 41%; P < .001). On multivariate analysis of OS, treatment regimen (relative risk [RR] of 1.94; P < .001), extent of surgical resection (RR of 1.80; P = .001), and interval from tumor diagnosis to WBRT (RR of 1.62; P = .010) were found to be statistically significant. On multivariate analysis of BC, treatment regimen (RR of 2.15; P = .002), extent of surgical resection (RR of 2.78; P < .001), and interval from tumor diagnosis to WBRT (RR of 1.52; P = .034) were found to be statistically significant. On multivariate analysis of LC, treatment regimen (RR of 2.31; P = .002) and extent of surgical resection (RR of 3.79; P < .001) were found to be statistically significant. On RPA class subgroup analyses, outcome was found to be significantly better with a WBRT boost in both RPA class 1 and class 2 patients. A WBRT boost resulted in better outcome after both complete and incomplete surgical resection. However, the results concerning BC and LC were not found to be statistically significant if surgical resection was incomplete. CONCLUSIONS. After surgical resection of 1 to 2 brain metastases, a boost of 10 to 15 Gy in addition to WBRT was found to improve outcome. After incomplete surgical resection, further dose escalation to the metastatic site may be considered. Cancer 2007. © 2007 American Cancer Society. [source] Survival by radiation therapy oncology group recursive partitioning analysis class and treatment modality in patients with brain metastases from malignant melanomaCANCER, Issue 8 2002A retrospective study Abstract BACKGROUND In a population of patients with brain metastases from melanoma, the authors sought to determine whether various therapies provided any benefit at all, whether local therapy was better than whole brain radiotherapy (WBRT), and whether combined local therapy and WBRT provided any advantage over local therapy alone. They also analyzed survival according to a Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) to determine how well the RTOG RPA classes predicted survival in this patient population and whether treatments varied in effectiveness from category to category. METHODS A total of 74 patients with brain metastases from melanoma were treated at The Cleveland Clinic Foundation between 1984 and 1998. For this study, the authors reviewed patient charts and confirmed survival status. Survival was compared by treatment modality (surgical resection, WBRT, stereotactic radiosurgery, or WBRT combined with local therapy). Survival also was compared according to the RTOG RPA prognostic classes (Class 1, Class 2, or Class 3), which has not been validated previously in patients with malignant melanoma. RESULTS The median survival was 5.5 months for all patients. Survival varied significantly by RTOG prognostic class; The median survival was 10.5 months (range, 2.2,99.2 months) for patients in Class 1, 5.9 months (range, 0.2,43.9 months) for patients in Class 2, and 1.8 months (range, 0.1,6.9 months) for patients in Class 3 (P < 0.0001). Survival analysis showed that combined treatment offered significantly better survival (P < 0.0001; combined vs. other). The median survival was 8.8 months (range, 1.8,99.2 months) for the combined therapy group, 4.8 months (range, 1.2,27.8 months) for the local therapy alone group, 2.3 months (range, 0.2,9.6 months) for the WBRT alone group, and 1.1 months (0.1,3.0 months) for the group that received no therapy. CONCLUSIONS Adding WBRT to local therapy may improve survival in this group of patients: Combined therapy was superior to WBRT alone. The RPA classification scheme likely has prognostic value for patients with brain metastases from malignant melanoma. Prospective studies are required to overcome selection bias and confirm these results. Cancer 2002;94:2265,72. © 2002 American Cancer Society. DOI 10.1002/cncr.10426 [source] | ||||||||||