23 results on '"Wilcken NR"'
Search Results
2. Capecitabine versus classical cyclophosphamide, methotrexate, and Fluorouracil as first-line chemotherapy for advanced breast cancer.
- Author
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Stockler MR, Harvey VJ, Francis PA, Byrne MJ, Ackland SP, Fitzharris B, Van Hazel G, Wilcken NR, Grimison PS, Nowak AK, Gainford MC, Fong A, Paksec L, Sourjina T, Zannino D, Gebski V, Simes RJ, Forbes JF, and Coates AS
- Published
- 2011
3. Life after adjuvant chemotherapy for breast cancer: the news is mostly good.
- Author
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Kiely BE, Wilcken NR, and Stockler MR
- Published
- 2011
- Full Text
- View/download PDF
4. Comparing patients' and their partners' preferences for adjuvant chemotherapy in early breast cancer.
- Author
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Duric VM, Butow PN, Sharpe L, Heritier S, Boyle F, Beith J, Wilcken NR, Coates AS, Simes RJ, and Stockler MR
- Abstract
OBJECTIVE: Preferences of women who had completed adjuvant chemotherapy for early breast cancer were compared with those of their partners by determining the smallest benefits they judged sufficient to make adjuvant chemotherapy worthwhile. METHODS: Forty-six women and their partners were interviewed separately, 3-34 months after completing adjuvant chemotherapy. Preferences were elicited using four sets of validated, hypothetical trade-off scenarios about the possible benefits of adjuvant chemotherapy on survival times (5 and 15 years) and survival rates (65% and 85% at 5 years). Agreement within couples was assessed with the intraclass correlation coefficient (ICC). Associations between baseline characteristics, preferences, and agreement within couples were assessed with linear regression after normal score transformation. RESULTS: The mean age of the women was 57 years and of their partners' was 60. Most couples were married (91%). Benefits of an extra 1 day or 0.1% were judged sufficient to make adjuvant chemotherapy worthwhile by 59-72% of women and 54-59% of partners. Agreement was exact in 35-41% of couples and approximate in 59-83%. Agreement was better for scenarios with a worse prognosis (ICC 0.67 and 0.35) than for scenarios with a better prognosis (ICC 0.13 and 0.05). Having dependent children was associated with partners requiring larger benefits but patients requiring smaller benefits to make adjuvant chemotherapy worthwhile (interaction P=0.001). CONCLUSION: Patients' and partners' preferences for adjuvant chemotherapy differed and were influenced by considerations other than length and quality of life. PRACTICE IMPLICATIONS: Clinicians who are aware of these differences can tailor discussions to ensure that all interested parties understand and agree on the goals and benefits of treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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5. The importance of early breast cancer treatment: delay can be deadly.
- Author
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Wilcken NR
- Subjects
- Humans, Female, Patient Acceptance of Health Care, Time Factors, Delayed Diagnosis, Breast Neoplasms diagnosis, Breast Neoplasms therapy
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- 2023
- Full Text
- View/download PDF
6. Impact of the EndoPredict genomic assay on treatment decisions for oestrogen receptor-positive early breast cancer patients: benefits of physician selective testing.
- Author
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Dinh P, Graham JD, Elder EN, Kabir M, Doan TB, French J, Meybodi F, Hui R, Wilcken NR, Harnett PR, Hsu J, Stuart KE, Wang T, Ahern V, Brennan M, Fox SB, Dear RF, Lim E, White M, Mann GB, and Pathmanathan N
- Subjects
- Chemotherapy, Adjuvant, Cohort Studies, Female, Genomics, Humans, Prognosis, Receptor, ErbB-2 genetics, Receptors, Estrogen genetics, Breast Neoplasms diagnosis, Breast Neoplasms drug therapy, Breast Neoplasms genetics, Physicians
- Abstract
Purpose: Genomic tests improve accuracy of risk prediction for early breast cancers but these are expensive. This study evaluated the clinical utility of EndoPredict®, in terms of impact on adjuvant therapy recommendations and identification of parameters to guide selective application., Methods: Patients with ER-positive, HER2-negative, and early-stage invasive breast cancer were tested with EndoPredict®. Two cohorts were recruited: one consecutively and another at clinical team discretion. Systemic treatment recommendations were recorded before and after EndoPredict® results were revealed to the multidisciplinary team., Results: 233 patients were recruited across five sites: 123 consecutive and 110 at clinical team discretion. In the consecutive cohort 50.6% (62/123) cases were classified high risk of recurrence by EndoPredict®, compared with 62.7% (69/110) in the selective cohort. A change in treatment recommendation was significantly more likely (p < 0.0001) in the selective cohort (43/110, 39.1%) compared to the consecutive group (11/123, 8.9%). The strongest driver of selective recruitment was intermediate grade histology, whilst logistic regression modelling demonstrated that nodal status (p < 0.001), proliferative rate (p = 0.001), and progesterone receptor positivity (p < 0.001) were the strongest discriminators of risk., Conclusion: Whilst molecular risk can be predicted by traditional variables in a high proportion of cases, EndoPredict® had a greater impact on treatment decisions in those cases selected for testing at team discretion. This is indicative of the robust ability of the clinical team to identify cases most likely to benefit from testing, underscoring the value of genomic tests in the oncologists' tool kit., (© 2021. Crown.)
- Published
- 2022
- Full Text
- View/download PDF
7. The median informs the message: accuracy of individualized scenarios for survival time based on oncologists' estimates.
- Author
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Kiely BE, Martin AJ, Tattersall MH, Nowak AK, Goldstein D, Wilcken NR, Wyld DK, Abdi EA, Glasgow A, Beale PJ, Jefford M, Glare PA, and Stockler MR
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- Aged, Female, Follow-Up Studies, Humans, Karnofsky Performance Status, Male, Middle Aged, Neoplasms therapy, Prognosis, Prospective Studies, Survival Rate, Time Factors, Life Expectancy, Medical Oncology, Mortality trends, Neoplasms mortality, Physician's Role
- Abstract
Purpose: To determine the accuracy and usefulness of oncologists' estimates of survival time in individual patients with advanced cancer., Patients and Methods: Twenty-one oncologists estimated the "median survival of a group of identical patients" for each of 114 patients with advanced cancer. Accuracy was defined by the proportions of patients with an observed survival time bounded by prespecified multiples of their estimated survival time. We expected 50% to live longer (or shorter) than their oncologist's estimate (calibration), 50% to live from half to double their estimate (typical scenario), 5% to 10% to live ≤ one quarter of their estimate (worst-case scenario), and 5% to 10% to live three or more times their estimate (best-case scenario). Estimates within 0.67 to 1.33 times observed survival were deemed precise. Discriminative value was assessed with Harrell's C-statistic and prognostic significance with proportional hazards regression., Results: Median survival time was 11 months. Oncologists' estimates were relatively well-calibrated (61% shorter than observed), imprecise (29% from 0.67 to 1.33 times observed), and moderately discriminative (Harrell C-statistic 0.63; P = .001). The proportion of patients with an observed survival half to double their oncologist's estimate was 63%, ≤ one quarter of their oncologist's estimate was 6%, and three or more times their oncologist's estimate was 14%. Independent predictors of observed survival were oncologist's estimate (hazard ratio [HR] = 0.92; P = .004), dry mouth (HR = 5.1; P < .0001), alkaline phosphatase more than 101 U/L (HR = 2.8; P = .0002), Karnofsky performance status ≤ 70 (HR = 2.3; P = .007), prostate primary (HR = 0.23; P = .002), and steroid use (HR = 2.4; P = .02)., Conclusion: Oncologists' estimates of survival time were relatively well-calibrated, moderately discriminative, independently associated with observed survival, and a reasonable basis for estimating worst-case, typical, and best-case scenarios for survival.
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- 2013
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8. First story--MJA Dr Eric Dark Creative Writing Prize.
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Wilcken NR
- Subjects
- Creativity, Female, Humans, Pregnancy, Awards and Prizes, Physician-Patient Relations, Writing
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- 2012
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9. High-risk estrogen-receptor-positive breast cancer: identification and implications for therapy.
- Author
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Balleine RL and Wilcken NR
- Subjects
- Breast Neoplasms drug therapy, Breast Neoplasms genetics, Breast Neoplasms pathology, Female, Humans, Prognosis, Receptors, Estrogen genetics, Breast Neoplasms metabolism, Receptors, Estrogen metabolism
- Abstract
The estrogen receptor (ER) has long been recognized as a key discriminative feature of breast cancer, which carries profound implications for management. However, recent advances in the understanding of breast cancer heterogeneity have demonstrated the importance of biologic context to the interpretation of ER as a prognostic and predictive factor. The use of tumor subtyping methods and prognostic indicators based on molecular profiling of tumor tissue is now helping to delineate high-risk ER-positive cancer types that have distinct risk and treatment response profiles. These new approaches to breast cancer classification will have a major impact on the conduct of clinical trials and individual patient assessment in the future.
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- 2012
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10. ACP Journal Club. Individual patient meta-analysis: taxane plus anthracycline reduces mortality from early breast cancer.
- Author
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Wilcken NR and Stockler MR
- Published
- 2012
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11. Why is management of cancer pain still a problem?
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Stockler MR and Wilcken NR
- Subjects
- Bortezomib, Female, Humans, Male, Analgesics therapeutic use, Antibodies, Monoclonal, Humanized administration & dosage, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Boronic Acids administration & dosage, Breast Neoplasms drug therapy, Colorectal Neoplasms drug therapy, Healthcare Disparities, Lung Neoplasms drug therapy, Multiple Myeloma drug therapy, Pain Management methods, Practice Patterns, Physicians', Prostatic Neoplasms drug therapy, Pyrazines administration & dosage
- Published
- 2012
- Full Text
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12. Decision making in older patients with advanced cancer: does doctor know best?
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Venkateswaran LP, Butow PN, Jansen J, Wilcken NR, Wong MK, Hui R, Szonyi G, Gebski VJ, Naganathan V, Horvath LG, and Tattersall MH
- Subjects
- Aged, Aged, 80 and over, Australia, Combined Modality Therapy standards, Humans, Middle Aged, Clinical Competence, Decision Making, Neoplasms therapy, Physicians standards
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- 2012
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13. Supporting treatment decision making in advanced cancer: a randomized trial of a decision aid for patients with advanced colorectal cancer considering chemotherapy.
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Leighl NB, Shepherd HL, Butow PN, Clarke SJ, McJannett M, Beale PJ, Wilcken NR, Moore MJ, Chen EX, Goldstein D, Horvath L, Knox JJ, Krzyzanowska M, Oza AM, Feld R, Hedley D, Xu W, and Tattersall MH
- Subjects
- Anxiety, Female, Humans, Male, Middle Aged, Pamphlets, Patient Care Management, Patient Education as Topic, Patient Participation, Patient Satisfaction, Quality of Life, Referral and Consultation, Surveys and Questionnaires, Videotape Recording, Antineoplastic Agents therapeutic use, Colorectal Neoplasms drug therapy, Decision Making, Decision Support Techniques
- Abstract
Purpose: Decision making in advanced cancer is increasingly complex. We developed a decision aid (DA) for patients with advanced colorectal cancer who are considering first-line chemotherapy and reviewing treatment options, prognostic information, and toxicities. We examined its impact on patient understanding, treatment decisions, decisional conflict, decision making, consultation satisfaction, anxiety, and quality of life by using a randomized trial design., Patients and Methods: In all, 207 patients with colorectal cancer who were considering first-line chemotherapy for metastatic disease were randomly assigned to receive a standard medical oncology consultation or a consultation in which the DA (take-home booklet with audio recording, reviewed by an oncologist) was used. Participants completed questionnaires postconsultation, postdecision, and 1 month later., Results: In this study, 100 patients were randomly assigned to the control arm, and 107 received the DA. Median age of the sample was 62 years, 58% were male, 89% had a performance status of 0 or 1, and 36% had received prior adjuvant chemotherapy. Patients receiving the DA demonstrated a greater increase in understanding of prognosis, options, and benefits, with higher overall understanding (P < .001). Decisional conflict, treatment decisions, and achievement of involvement preferences were similar between the groups. Anxiety was similar across groups and decreased over time. Most patients were confident in a decision during the first consultation; 74% chose chemotherapy, 7% supportive care alone, and 10% observation., Conclusion: This randomized trial of a decision aid in advanced cancer showed that its use in advanced colorectal cancer improved patient understanding of prognosis, treatment options, risks, and benefits without increasing anxiety. DAs can improve informed consent and can be tested through randomized trials even in the advanced cancer setting.
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- 2011
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14. Effect of sertraline on symptoms and survival in patients with advanced cancer, but without major depression: a placebo-controlled double-blind randomised trial.
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Stockler MR, O'Connell R, Nowak AK, Goldstein D, Turner J, Wilcken NR, Wyld D, Abdi EA, Glasgow A, Beale PJ, Jefford M, Dhillon H, Heritier S, Carter C, Hickie IB, and Simes RJ
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- Aged, Depressive Disorder psychology, Diagnostic and Statistical Manual of Mental Disorders, Double-Blind Method, Female, Follow-Up Studies, Humans, Male, Middle Aged, Neoplasms psychology, Placebos, Psychiatric Status Rating Scales, Quality of Life psychology, Survival Rate, Treatment Outcome, Antidepressive Agents therapeutic use, Depressive Disorder drug therapy, Neoplasms mortality, Sertraline therapeutic use
- Abstract
Background: Depression, anxiety, fatigue, and impaired wellbeing are common, important, and closely related in advanced cancer. We aimed to identify the effects of an established antidepressant on these symptoms and survival in patients with advanced cancer who did not have major depression as assessed by clinicians., Methods: Between July, 2001, and February, 2006, 189 patients with advanced cancer were randomly assigned sertraline 50 mg (n=95), or placebo (n=94), once per day. The primary outcome was depression as assessed by the Centre for Epidemiologic Studies Depression scale (CES-D); the main secondary outcomes were: anxiety as assessed by Hospital Anxiety and Depression Scales (HADS-A); overall quality of life and fatigue as assessed by Functional Assessment of Cancer Therapy General and Fatigue scales (FACT-G and FACT-F, respectively); and clinicians' ratings of quality of life by use of Spizter's Quality of Life Index (SQLI). Multiple measures were used for corroboration of the most important outcomes. Primary analyses were done by intention to treat and were based on scale scores at 4 weeks and 8 weeks. The benefits of sertraline compared with placebo are expressed on a range from +100 (ie, maximum benefit) to -100 (ie, maximum harm); a difference of 10 was deemed clinically significant. This clinical trial is registered at Current Controlled Trials website http://www.controlled-trials.com/ISRCTN72466475., Findings: Sertraline had no significant effect (scale, benefit over placebo [95% CI]) on depression (CES-D 0.4 [-2.6 to 3.4]), anxiety (HADS-A 2.0 [-1.5 to 5.5]), fatigue (FACT-F 0.3 [-4.3 to 4.9]), overall quality of life (FACT-G 1.7 [-1.3 to 4.7]), or clinicians' ratings (SQLI 2.0 [-2.5 to 6.5]), and the 95% CI ruled out a clinically significant benefit for all main outcomes. Sertraline was discontinued more often and earlier than was placebo (hazard ratio 1.46 [1.03-2.06], p=0.03). Recruitment was stopped after the first planned interim analysis in February 2006 (n=150) showed that survival was longer in patients assigned placebo than in patients assigned sertraline (unadjusted hazard ratio 1.60 [95% CI 1.04-2.45], log-rank p=0.04; adjusted hazard ratio 1.62 [1.06-2.41], Cox model p=0.02). However, at the final analysis in July 2006 of all patients (n=189) and with longer follow-up, survival did not differ significantly between the treatment groups (unadjusted hazard ratio 1.35 [0.95-1.91], log-rank p=0.09; adjusted hazard ratio 1.27 [0.87-1.84], Cox model p=0.20). The trial was closed because it had ruled out a significant benefit of sertraline., Interpretation: Sertraline did not improve symptoms, wellbeing, or survival in patients with advanced cancer who do not have major depression, and should be reserved for those with a proven indication.
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- 2007
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15. Putting results of a clinical trial into perspective.
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Wilcken NR, Gebski VJ, Pike R, and Keech AC
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- Bias, Evidence-Based Medicine, Humans, Meta-Analysis as Topic, Patient Care, Patient Selection, Patients, Randomized Controlled Trials as Topic, Research Design, Risk Assessment, Treatment Outcome, Clinical Trials as Topic
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- 2007
- Full Text
- View/download PDF
16. Psychosocial factors and patients' preferences for adjuvant chemotherapy in early breast cancer.
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Duric VM, Butow PN, Sharpe L, Boyle F, Beith J, Wilcken NR, Heritier S, Coates AS, John Simes R, and Stockler MR
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- Adult, Aged, Anxiety, Breast Neoplasms drug therapy, Choice Behavior, Female, Humans, Middle Aged, Social Support, Surveys and Questionnaires, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Breast Neoplasms psychology, Chemotherapy, Adjuvant psychology, Patient Satisfaction
- Abstract
Purpose: Many women who have had adjuvant chemotherapy for early breast cancer judge small benefits sufficient to make it worthwhile despite significant side effects and inconvenience. The rationality of these preferences has been questioned. We sought to better understand such preferences by assessing associations between preferences and psychosocial factors, and by asking women who judged negligible benefits sufficient to explain why., Methods: We recruited 83 consecutive consenting women who had completed adjuvant chemotherapy for early breast cancer 3-34 months earlier. Preferences were elicited during a structured, scripted interview using four sets of validated, hypothetical trade-off scenarios about the possible benefits of adjuvant chemotherapy on survival times (5 and 15 years) and rates (65 and 85% at 5 years). Women completed questionnaires measuring anxiety, depression, optimism, quality and quantity of social support, and illness perceptions., Results: More than half the women judged benefits of 1 day or 0.1% sufficient to make adjuvant chemotherapy worthwhile. The most important factors in multivariable models were whether the woman had dependants and number of non-specific symptoms attributed to breast cancer and adjuvant chemotherapy since completing treatment. The proportion of variance explained was modest. Preferences were not associated with: scores for anxiety, optimism, and perceived quality and quantity of social support. Explanations for judging negligible benefits sufficient included minimising regret, parenting concerns, doubts about the information provided and feeling that they had no choice., Conclusions: Preferences were highly variable and influenced by women's unique circumstances and attitudes, but not by their anxiety or optimism scores., (Copyright 2006 John Wiley & Sons, Ltd.)
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- 2007
- Full Text
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17. Systematic review of taxane-containing versus non-taxane-containing regimens for adjuvant and neoadjuvant treatment of early breast cancer.
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Nowak AK, Wilcken NR, Stockler MR, Hamilton A, and Ghersi D
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- Adult, Aged, Breast Neoplasms mortality, Breast Neoplasms surgery, Chemotherapy, Adjuvant, Docetaxel, Female, Follow-Up Studies, Humans, Infusions, Intravenous, Mastectomy methods, Middle Aged, Neoadjuvant Therapy, Neoplasm Staging, Paclitaxel adverse effects, Paclitaxel therapeutic use, Randomized Controlled Trials as Topic, Risk Assessment, Survival Analysis, Taxoids adverse effects, Treatment Outcome, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Breast Neoplasms drug therapy, Breast Neoplasms pathology, Taxoids therapeutic use
- Abstract
The use of taxanes in early breast cancer is increasing. However, there are few mature studies of taxanes in this setting, and their role is uncertain. Our systematic review of randomised trials of adjuvant or neoadjuvant systemic therapy identified ten reported trials comparing a taxane-containing group with a non-taxane-containing control group in women with early breast cancer. Four of five neoadjuvant trials showed higher rates of complete response with taxanes, although differences were not significant. All five adjuvant trials showed improvements in disease-free survival with taxanes, and these improvements were significant in three trials and independent of oestrogen-receptor status. Two trials showed a significant improvement in overall survival. These results support the use of adjuvant taxanes in women with early breast cancer and involved lymph nodes. Longer follow-up of these trials and results from continuing trials are needed to clarify the best use of taxanes in early breast cancer.
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- 2004
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18. Fulvestrant: spreading the word, but not too thinly.
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Wilcken NR and Stockler MR
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- Duplicate Publications as Topic, Female, Fulvestrant, Humans, Information Dissemination methods, Publishing standards, Statistics as Topic standards, Treatment Outcome, Breast Neoplasms drug therapy, Clinical Trials as Topic statistics & numerical data, Estradiol analogs & derivatives, Estradiol therapeutic use, Estrogen Receptor Modulators therapeutic use, Publishing statistics & numerical data
- Published
- 2003
- Full Text
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19. Systematic reviews of chemotherapy and endocrine therapy in metastatic breast cancer.
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Stockler M, Wilcken NR, Ghersi D, and Simes RJ
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- Antineoplastic Combined Chemotherapy Protocols therapeutic use, Female, Humans, Antineoplastic Agents therapeutic use, Breast Neoplasms drug therapy, Breast Neoplasms secondary, Estrogen Receptor Modulators therapeutic use
- Abstract
Metastatic breast cancer is incurable but often responsive to treatment. There is little evidence-based consenus on when to use which treatments, in what combination and for how long. Systematic reviews were performed on 12 prospectively defined, clinically relevant research questions to support the development of evidence-based clinical practice guidelines. A comprehensive search of Medline from 1966 to 1996 identified over 1800 controlled trials. Eligibility and data extraction were performed independently by two blinded reviewers. Trial results were summarised by ratios of median survivals (RMS) and P -values for survival curve comparisons with meta-analysis by weighted combination of these statistics. Sixty-five publications reporting 97 treatment comparisons were included. There was moderate evidence that more rather than fewer cycles of chemotherapy improved survival (RMS:1.23, P -0.01). The evidence did not support: higher rather than lower doses of chemotherapy (or of endocrine therapy); any one class of endocrine agent over all others; multiple endocrine agents over a single agent; or, combined chemotherapy and endocrine therapy over either single modality. Only six trials assessed quality of life revealing better quality of life with more rather than fewer cycles of chemotherapy and with standard rather than lower doses of chemotherapy. These systematic reviews reveal counterintuitive evidence useful to everyday practice, in particular that more rather than fewer cycles of chemotherapy lead to better quality of life and longer survival., (Copyright 2000 Harcourt Publishers Ltd.)
- Published
- 2000
- Full Text
- View/download PDF
20. Tamoxifen hits the target in situ.
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Wilcken NR
- Subjects
- Breast Neoplasms therapy, Combined Modality Therapy, Female, Humans, Neoplasm Recurrence, Local prevention & control, Anticarcinogenic Agents therapeutic use, Antineoplastic Agents, Hormonal therapeutic use, Breast Neoplasms drug therapy, Carcinoma, Intraductal, Noninfiltrating drug therapy, Tamoxifen therapeutic use
- Published
- 1999
- Full Text
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21. Inducible overexpression of cyclin D1 in breast cancer cells reverses the growth-inhibitory effects of antiestrogens.
- Author
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Wilcken NR, Prall OW, Musgrove EA, and Sutherland RL
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- Breast Neoplasms, Cell Cycle drug effects, Cell Division drug effects, Cyclin D1 metabolism, Cyclin-Dependent Kinase 4, Cyclin-Dependent Kinases metabolism, Drug Resistance, Neoplasm, Estradiol toxicity, Female, Fulvestrant, Humans, Polyunsaturated Alkamides, S Phase, Tumor Cells, Cultured, Zinc Sulfate pharmacology, Antineoplastic Agents toxicity, Cyclin D1 genetics, Estradiol analogs & derivatives, Estrogen Antagonists toxicity, Gene Expression Regulation, Neoplastic, Proto-Oncogene Proteins, Tamoxifen toxicity
- Abstract
The development of endocrine resistance in previously sensitive, estrogen receptor-positive breast cancers is a major limitation in the treatment of breast cancer. Because antiestrogens have a cell cycle-specific action on breast cancer cells and influence the expression and activity of several cell cycle-regulatory molecules, the development of aberrant cell cycle control mechanisms is a potential mechanism by which cells might develop resistance to antiestrogens. We postulated that overexpression of cyclin D1, which is a common feature of breast cancer, may confer antiestrogen resistance. We addressed this question in vitro by testing the ability of ectopic cyclin D1 overexpression to overcome the growth-inhibitory effects of tamoxifen and the pure steroidal antiestrogens, ICI 164384 and ICI 182780, in T-47D and MCF-7 human breast cancer cells. In cells stably transfected with a human cyclin D1 cDNA under the control of a metal-inducible metallothionein promoter, cyclin D1 expression was increased 2-4-fold following treatment with zinc. Despite the continued presence of antiestrogen, cyclin D1 induction resulted in the formation of active cyclin D1/Cdk4 complexes, concurrent hyperphosphorylation of the retinoblastoma protein, and entry into S phase of cells previously arrested in G1. Elevated cyclin D1 protein levels were first detected 3 h after treatment with zinc, and the proportion of cells in S phase began to increase 6 h later. The S-phase fraction increased 2-3-fold from 13 to 17% in cells treated with antiestrogen alone, to a peak of 33-38% 15 h after zinc treatment. Both the cyclin D1 protein level and the proportion of cells in S phase increased with increasing concentrations of zinc. We conclude that the ectopic overexpression of cyclin D1 reverses the growth-inhibitory effect of antiestrogens in estrogen receptor-positive breast cancer cells, providing a potential mechanism for clinical antiestrogen resistance.
- Published
- 1997
22. Different points of action of retinoids and anti-estrogens in G1 phase identified in synchronized T-47D breast cancer cells.
- Author
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Wilcken NR, Musgrove EA, and Sutherland RL
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- Cell Division drug effects, Enzyme Inhibitors pharmacology, Estradiol pharmacology, Female, G1 Phase drug effects, G2 Phase drug effects, Humans, Lovastatin pharmacology, Polyunsaturated Alkamides, S Phase drug effects, Time Factors, Tumor Cells, Cultured drug effects, Cell Cycle drug effects, Estradiol analogs & derivatives, Estrogen Antagonists pharmacology, Tretinoin pharmacology
- Abstract
Both retinoids and anti-estrogens inhibit breast cancer cell proliferation with accumulation of cells in the G1 phase of the cell cycle, but the effect of retinoids is delayed compared to that of anti-estrogens. To determine whether this temporal difference is due to a simple delay in the action of retinoids on a common site or to different sites of action within the G1 phase, we studied the cell cycle effects of retinoic acid (RA) and the anti-estrogen ICI 164384 (ICI) in T-47D cells partially synchronized by mevalonic acid rescue of lovastatin-induced cell cycle arrest. We found that cells entering the cell cycle semi-synchronously after mevalonic acid rescue of lovastatin treatment were immediately susceptible to ICI but not RA. This suggests that RA may act at a point up-stream and ICI at a point down-stream of lovastatin action. Consistent with this, cells recommencing cell cycle progression after RA treatment were susceptible to the effects of lovastatin, while cells pre-treated with ICI then rescued with estradiol were not. In addition, cells rescued from cell cycle arrest induced by either RA, ICI or lovastatin entered S phase with the same kinetics. Our findings suggest, first, that within G1, RA acts before and ICI acts after the point of lovastatin action and, second, that despite these differences in the initiation of cell cycle arrest, the final nature of the cell cycle arrest is similar. Hence, retinoids and anti-estrogens may be expected to target different cell cycle-regulatory molecules to initiate cell cycle arrest, while overcoming this arrest may be accomplished by the activation of a common molecular pathway.
- Published
- 1997
- Full Text
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23. Differential effects of retinoids and antiestrogens on cell cycle progression and cell cycle regulatory genes in human breast cancer cells.
- Author
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Wilcken NR, Sarcevic B, Musgrove EA, and Sutherland RL
- Subjects
- Cell Cycle drug effects, Cell Cycle genetics, Cell Division drug effects, Cyclin D1, Cyclin-Dependent Kinases genetics, Cyclins genetics, Estradiol pharmacology, Female, G1 Phase drug effects, Gene Expression Regulation, Neoplastic drug effects, Humans, Oncogene Proteins genetics, Phosphorylation, Polyunsaturated Alkamides, Proto-Oncogene Proteins c-myc genetics, Time Factors, Tumor Cells, Cultured cytology, Tumor Cells, Cultured drug effects, Tumor Cells, Cultured enzymology, Breast Neoplasms, Estradiol analogs & derivatives, Estrogen Antagonists pharmacology, Retinoids pharmacology
- Abstract
Retinoids have antiproliferative effects in human breast cancer cells and share some characteristics with antiestrogens, although the molecular targets involved have yet to be identified in either case. Using T-47D human breast cancer cells, we compared the effects of retinoic acid (RA) and the antiestrogen ICI 164384 on cell cycle phase distribution and the expression of genes with known functions in cell cycle control. Both RA and ICI 164384 inhibited cell cycle progression in G1 phase, but the RA effect was delayed by 16 h. This delay in action was also seen with 9-cis RA and other retinoids. Administration of 17 beta-estradiol abolished the effects of ICI 164384 but was without effect in RA-treated cells. Antiestrogen treatment caused a rapid inhibition of c-myc and cyclin D1 gene expression and reduced Cdk2 activity by more than 50% at 24 h. RA, however, did not affect c-myc or cyclin D1 gene expression, nor did it significantly change the mRNA or protein levels of cyclins D3 or E or cyclin-dependent kinases (CDK) Cdk2 or Cdk4. RA-induced reduction in Cdk2 activity was modest and occurred after %S phase declined, while Cdk4 activity was reduced, coincident with cell cycle changes. However, following either RA or ICI 164384, there was a reduction in the amount of hyperphosphorylated pRB, first apparent well before cell cycle changes were seen. These data demonstrate that: (a) the mechanisms of action of antiestrogens and retinoids are different but converge at pRB; and (b) RA can affect CDK activity without reducing cyclin or CDK levels.
- Published
- 1996
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