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Biomedical subjects

Anthony Howell

Publications and source records attributed to Anthony Howell.

At least 19 recordsLinked to original sources
PubMed2006

Late toxicity is not increased in BRCA1/BRCA2 mutation carriers undergoing breast radiotherapy in the United Kingdom.

PURPOSE: To undertake the first substantial clinical study of breast radiotherapy toxicity in BRCA1 and BRCA2 mutation carriers in the United Kingdom. EXPERIMENTAL DESIGN: Acute and late radiation effects were evaluated in a retrospective study of 55 BRCA1 and BRCA2 mutation carriers treated with radiotherapy for breast cancer at four centers between 1983 and 2002. Individual matching with controls who had sporadic breast cancer was undertaken for age at diagnosis, time since completion of radiation, and treatment variables. Detailed assessments were undertaken by one examiner. Median follow-up was 6.75 years for carriers and 7.75 years for controls. Rates of late events (rib fractures, lung fibrosis, necrosis of soft tissue/bone, and pericarditis) as well as LENT-SOMA scores and clinical photography scores of breast size, shape, and skin telangiectasia were the primary end points. RESULTS: No increase in clinically significant late toxicity was seen in the mutation carriers. CONCLUSIONS: These data add substantial weight to the evidence that the outcomes in the treated breast from radiotherapy in women with BRCA1 or BRCA2 mutations are comparable with those in women with sporadic breast cancer.

Adult↗
PubMed2006

Acute chemotherapy-related toxicity is not increased in BRCA1 and BRCA2 mutation carriers treated for breast cancer in the United Kingdom.

PURPOSE: To evaluate acute toxicity induced by chemotherapy for breast cancer in a retrospective study of 62 BRCA1/2 mutation carriers matched 1:1 with women who had treatment for sporadic disease in the United Kingdom between 1983 and 2003. EXPERIMENTAL DESIGN: All participants were interviewed by one of two researchers using standardized questionnaires, and their medical records were reviewed by one research nurse. The two main regimens received were cyclophosphamide, methotrexate, and fluorouracil and fluorouracil, epirubicin, and cyclophosphamide. The proportion of cases and controls receiving anthracycline-based treatment was equivalent, but fewer BRCA1 cases received this treatment than did BRCA2 mutation carriers. Toxicity was documented using the Eastern Cooperative Oncology Group Common Toxicity Criteria for hematologic, infective, and gastrointestinal toxicities. No increase in toxicity was seen in BRCA1/2 mutation carriers. RESULTS: The only significant difference was that neutropenia was less evident in BRCA2 mutation carriers than in either BRCA1 mutation carriers or controls. As a result, there was no requirement for dose reduction among BRCA2 mutation carriers, in contrast to 10 of 39 BRCA1 carriers and 16 of 62 controls (P = 0.02). CONCLUSIONS: This result has implications for therapy and indicates that women with mutations in BRCA1 and BRCA2 may be given the same doses of chemotherapy as noncarriers.

Adult↗
PubMed2006

Quality of life of postmenopausal women in the ATAC ("Arimidex", tamoxifen, alone or in combination) trial after completion of 5 years' adjuvant treatment for early breast cancer.

The impact of treatment on health-related quality of life (HRQoL) is an important consideration in the adjuvant treatment of operable breast cancer. Here we report mature HRQoL outcomes from the ATAC trial, comparing anastrozole with tamoxifen as primary adjuvant therapy for postmenopausal women with localized breast cancer. Patients completed the Functional Assessment of Cancer Therapy-Breast (FACT-B) questionnaire plus endocrine subscale (ES) at baseline, 3 and 6 months, and every 6 months thereafter. Baseline characteristics in the HRQoL sub-protocol were well balanced between the anastrozole (n = 335) and tamoxifen (n = 347) groups in the primary analysis population. As with previously published results at 2 years, there was no statistically significant difference in the Trial Outcome Index of the FACT-B, the primary endpoint of the study, between treatments at 5 years. There were no statistically significant differences between treatment groups in ES total scores. Consistent with the 2-year analysis, there were differences between treatment groups in patient-reported side effects: diarrhea (anastrozole 3.1% vs. tamoxifen 1.3%), vaginal dryness (18.5% vs. 9.1%), diminished libido (34.0% vs. 26.1%), and dyspareunia (17.3% vs. 8.1%) were significantly more frequent with anastrozole compared to tamoxifen. Dizziness (3.1% vs. 5.4%) and vaginal discharge (1.2% vs. 5.2%) were significantly less frequent with anastrozole compared to tamoxifen. In this, the first report of HRQoL over 5 years of initial adjuvant therapy with an aromatase inhibitor, we conclude that anastrozole and tamoxifen had similar impacts on HRQoL, which was maintained or slightly improved during the treatment period for both groups.

Anastrozole↗
PubMed2006

BRCA1, BRCA2 and TP53 mutations in very early-onset breast cancer with associated risks to relatives.

Pathological mutations in BRCA1, BRCA2 and TP53 are associated with an increased risk of breast cancer. This study evaluated mutation frequency of these genes in early-onset breast cancer patients, and correlated this with family history and determined relative risks to family members. Patients with breast adenocarcinoma diagnosed 30 years were ascertained between 1980 and 1997. Family history was established and mutation screening of BRCA1, BRCA2 and TP53 genes was performed. Estimates of penetrance and relative risk were undertaken. DNA was obtained from 100/139 women. 17/36 familial cases had a BRCA1, BRCA2 or TP53 mutation. Of 64 non-familial cases, one BRCA2, two BRCA1 and two TP53 mutations were detected. Penetrance estimates (by age 70) for breast cancer were 84% for BRCA1 mutations and 91% for BRCA2 mutations and for ovarian cancer, 60% and 26%, respectively. Relative risks associated with mutations were consistent with previous studies. BRCA1 and BRCA2 mutations in patients with breast cancer 30 years are predicted strongly by family history. The majority of families with ovarian cancer were due to mutations in BRCA1/2 whereas these mutations only accounted for 30-50% of the excess breast cancers.

Adenocarcinoma↗
PubMed2006

Fulvestrant ('Faslodex'): current and future role in breast cancer management.

Fulvestrant ('Faslodex') is a new type of estrogen receptor antagonist with no agonist effects, that reduces cellular levels of both estrogen and progesterone receptors. Results from two Phase III trials showed that fulvestrant is at least as effective as the third-generation selective aromatase inhibitor anastrozole in postmenopausal women with advanced breast cancer following progression on antiestrogen therapy, indicating the potential for second-line fulvestrant in this setting. In clinical practice, fulvestrant is well tolerated, with good rates of clinical benefit observed as first-line therapy and following progression on prior endocrine agents. Other endocrine agents have been shown to have good clinical activity when resistance to fulvestrant has developed, showing that fulvestrant lacks cross-resistance with other treatments. Ongoing trials are investigating the efficacy of fulvestrant after failure on aromatase inhibitors and evaluating its use in combination with therapies that target growth factor receptor signaling pathways.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

High-throughput genomic technology in research and clinical management of breast cancer. Exploiting the potential of gene expression profiling: is it ready for the clinic?

Gene expression profiling is a relatively new technology for the study of breast cancers, but within the past few years there has been a rapid rise in interest in its potential to improve the clinical management of breast cancer. This technology has contributed to our knowledge of the molecular pathology of breast tumours and shows promise as a tool to predict response to therapy and outcome, such as risk of metastasis. Microarray technology is continually developing and it is becoming apparent that, despite the various platforms available, robust conclusions can still be drawn that apply across the different array types. Gene expression profiling is beginning to appear in the breast cancer clinic but it is not yet fully evaluated. This review explores the questions that must be addressed before this technology can become an everyday clinical tool.

Breast Neoplasms↗
PubMed2006

Pure oestrogen antagonists for the treatment of advanced breast cancer.

For more than 30 years, tamoxifen has been the drug of choice in treating patients with oestrogen receptor (ER)-positive breast tumours. However, research has endeavoured to develop agents that match and improve the clinical efficacy of tamoxifen, but lack its partial agonist effects. The first 'pure' oestrogen antagonist was developed in 1987; from this, an even more potent derivative was developed for clinical use, known as fulvestrant (ICI 182,780, 'Faslodex'). Mechanistic studies have shown that fulvestrant possesses high ER-binding affinity and has multiple effects on ER signalling: it blocks dimerisation and nuclear localisation of the ER, reduces cellular levels of ER and blocks ER-mediated gene transcription. Unlike anti-oestrogens chemically related to tamoxifen, fulvestrant also helps circumvent resistance to tamoxifen. There are extensive data to support the lack of partial agonist effects of fulvestrant and, importantly, its lack of cross-resistance with tamoxifen. In phase III studies in patients with locally advanced or metastatic breast cancer, fulvestrant was at least as effective as anastrozole in patients with tamoxifen-resistant tumours, was effective in the first-line setting and was also well tolerated. These data are supported by experience from the compassionate use of fulvestrant in more heavily pretreated patients. Further studies are now underway to determine the best strategy for sequencing oestrogen endocrine therapies and to optimise dosing regimens offulvestrant. At present, and for the foreseeable future, fulvestrant is the only oestrogen antagonist with no agonistic effects licensed for the treatment of advanced breast cancer in postmenopausal women. Other similar oestrogen antagonists are undergoing research and development, with a few currently being evaluated in phase II trials.

Antineoplastic Agents↗
PubMed2006

Insulin-like growth factor (IGF)-I, IGF binding protein-3, and breast cancer risk: eight years on.

Insulin-like growth factor (IGF)-I, and its main binding protein, IGFBP-3, are multi-functional regulatory peptides of cell growth and survival, attributes important for tumourigenesis. Following seminal work published in 1998, it has been hypothesised that circulating concentrations of these growth factors may be associated with cancer risk. Systematic reviews have reported that high normal range circulating levels of total IGF-I predict for pre- but not post-menopausal breast cancer. By contrast, associations with circulating IGFBP-3 have been inconsistent. A cumulative meta-analysis demonstrates that earlier reported positive associations between IGFBP-3 and pre-menopausal breast cancer risk now seem less clear as large-size cohorts are published. The reasons are complex and include differences in study design, lack of standardisation between assays, and variations in IGFBP-3 proteolytic activity--these are discussed in this commentary.

Breast Neoplasms↗
PubMed2005

Phase III trial of epirubicin plus paclitaxel compared with epirubicin plus cyclophosphamide as first-line chemotherapy for metastatic breast cancer: United Kingdom National Cancer Research Institute trial AB01.

PURPOSE: To compare the effectiveness and tolerability of epirubicin and paclitaxel (EP) with epirubicin and cyclophosphamide (EC) as first-line chemotherapy for metastatic breast cancer (MBC). PATIENTS AND METHODS: Patients previously untreated with chemotherapy (except for adjuvant therapy) were randomly assigned to receive either EP (epirubicin 75 mg/m2 and paclitaxel 200 mg/m2) or EC (epirubicin 75 mg/m2 and cyclophosphamide 600 mg/m2) administered intravenously every 3 weeks for a maximum of six cycles. The primary outcome was progression-free survival; secondary outcome measures were overall survival, response rates, and toxicity. RESULTS: Between 1996 and 1999, 705 patients (353 EP patients and 352 EC patients) underwent random assignment. Patient characteristics were well matched between the two groups, and 71% of patients received six cycles of treatment. Objective response rates were 65% for the EP group and 55% for the EC group (P = .015). At the time of analysis, 641 patients (91%) had died. Median progression-free survival time was 7.0 months for the EP group and 7.1 months for the EC group (hazard ratio = 1.07; 95% CI, 0.92 to 1.24; P = .41), and median overall survival time was 13 months for the EP group and 14 months for the EC group (hazard ratio = 1.02; 95% CI, 0.87 to 1.19; P = .8). EP patients, compared with EC patients, had more grade 3 and 4 mucositis (6% v 2%, respectively; P = .0006) and grade 3 and 4 neurotoxicity (5% v 1%, respectively; P < .0001). CONCLUSION: In terms of progression-free survival and overall survival, there was no evidence of a difference between EP and EC. The data demonstrate no additional advantage to using EP instead of EC as first-line chemotherapy for MBC in taxane-naïve patients.

Adult↗
PubMed2005

New developments in the treatment of postmenopausal breast cancer.

In recent years, new agents have challenged tamoxifen as the standard endocrine therapy for postmenopausal breast cancer. This article reviews developments with regard to the third-generation aromatase inhibitors (AIs)--anastrozole, letrozole and exemestane--and fulvestrant, the first of a new type of estrogen receptor antagonist that, unlike tamoxifen, has no partial agonist activity. The final results of the "Arimidex", Tamoxifen, Alone or in Combination (ATAC) trial, at a median follow-up of more than five years, and recent results from switching studies with anastrozole and exemestane, strengthen the position of these AIs as adjuvant treatment for hormone receptor-positive early breast cancer. Sequencing options for the future are also discussed because non-steroidal AIs are increasingly used early in the treatment sequence.

Anastrozole↗
PubMed2005

The future of fulvestrant ("Faslodex").

Changes in clinical practice regarding favoured first-line and adjuvant treatments for postmenopausal women with advanced breast cancer (ABC) mean that it is becoming increasingly important to identify agents that are effective following aromatase inhibitor (AI) failure as well as tamoxifen failure. Fulvestrant ("Faslodex") is a new oestrogen receptor (ER) antagonist with no agonist effects that binds, blocks and degrades the ER. Fulvestrant is at least as effective as anastrozole following tamoxifen failure and also shows activity after progression on AIs. Its very good tolerability profile and novel mode of action, might offer potential for the use of fulvestrant in combination regimens, and there is also scope for investigating the use of loading and higher dose regimens in an attempt to further enhance efficacy. Here, the rationale and evidence for the efficacy of fulvestrant following AI failure and its combination with AIs and novel agents such as gefitinib and trastuzumab will be reviewed. The ongoing clinical development programme for fulvestrant will more fully the role of this valuable new agent in the treatment of postmenopausal ABC.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Clinical development of fulvestrant ("Faslodex").

This paper outlines the development of fulvestrant, the first in a new class of antioestrogen agents with no agonist effects, to be used for the treatment of hormone receptor-positive advanced breast cancer in postmenopausal women. The role of the oestrogen receptor in breast cancer growth and development and the evolution of pharmacological strategies to manipulate it are also discussed. Preclinical and clinical evidence for the efficacy of fulvestrant are also reviewed, along with the tolerability profile of this agent in relation to other endocrine therapies. Further research will define the role of this exciting new agent in the endocrine treatment of breast cancer.

Aged↗
PubMed2005

Fulvestrant versus anastrozole for the treatment of advanced breast carcinoma: a prospectively planned combined survival analysis of two multicenter trials.

BACKGROUND: Fulvestrant is an estrogen receptor antagonist with no agonist effects. In the second-line treatment of advanced breast carcinoma, fulvestrant was shown previously to be as effective as the third-generation aromatase inhibitor, anastrozole, in terms of time to disease progression and objective response rates. The authors reported the overall survival results from these studies. METHODS: A prospectively planned, combined, overall survival analysis was performed, including data from two Phase III trials that compared the efficacy and tolerability of fulvestrant (250 mg monthly; n = 428) with anastrozole (1 mg daily; n = 423) in the treatment of postmenopausal women with advanced breast carcinoma who had disease progression after receipt of previous endocrine treatment. RESULTS: At an extended median follow-up of 27.0 months (range, 0-66.9 months), 319 (74.5%) patients in the fulvestrant group and 322 (76.1%) patients in the anastrozole group had died. Prolonged survival was observed with both drugs, with 10-20% of patients still alive > 5 years after randomization. The median overall survival was similar between treatments, being 27.4 months and 27.7 months in fulvestrant and anastrozole-treated patients, respectively (hazards ratio, 0.98; 95% confidence interval, 0.84-1.15; P = 0.809). Fulvestrant continued to be well tolerated, and was associated with a significantly lower incidence of joint disorders compared with anastrozole (P = 0.0234). CONCLUSIONS: The current analysis showed that fulvestrant was similar to anastrozole with respect to overall survival in the second-line treatment of postmenopausal women with advanced breast carcinoma.

Anastrozole↗
PubMed2005

Early stopping of clinical trials.

Early stopping of clinical trials in favour of a new treatment creates ethical and scientific difficulties, which are different from those associated with early stopping due to toxicity or futility. Two major breast cancer trials have recently taken such a decision, and the problem is relevant for several ongoing trials. Here we argue that such a decision should be taken with the utmost gravity and should be based on a clear overall clinical benefit for the new treatment, and not as an automatic response to crossing a predefined threshold. Predefined rules can be used to trigger a debate within the Independent Data Monitoring and Safety Committee (IDMC) about early stopping, but the IDMC should retain the responsibility of assessing overall clinical benefit in making its recommendation.

Breast Neoplasms↗
PubMed2005

Adjuvant docetaxel for node-positive breast cancer.

BACKGROUND: We compared docetaxel plus doxorubicin and cyclophosphamide (TAC) with fluorouracil plus doxorubicin and cyclophosphamide (FAC) as adjuvant chemotherapy for operable node-positive breast cancer. METHODS: We randomly assigned 1491 women with axillary node-positive breast cancer to six cycles of treatment with either TAC or FAC as adjuvant chemotherapy after surgery. The primary end point was disease-free survival. RESULTS: At a median follow-up of 55 months, the estimated rates of disease-free survival at five years were 75 percent among the 745 patients randomly assigned to receive TAC and 68 percent among the 746 randomly assigned to receive FAC, representing a 28 percent reduction in the risk of relapse (P=0.001) in the TAC group. The estimated rates of overall survival at five years were 87 percent and 81 percent, respectively. Treatment with TAC resulted in a 30 percent reduction in the risk of death (P=0.008). The incidence of grade 3 or 4 neutropenia was 65.5 percent in the TAC group and 49.3 percent in the FAC group (P<0.001); rates of febrile neutropenia were 24.7 percent and 2.5 percent, respectively (P<0.001). Grade 3 or 4 infections occurred in 3.9 percent of the patients who received TAC and 2.2 percent of those who received FAC (P=0.05); no deaths occurred as a result of infection. Two patients in each group died during treatment. Congestive heart failure and acute myeloid leukemia occurred in less than 2 percent of the patients in each group. Quality-of-life scores decreased during chemotherapy but returned to baseline levels after treatment. CONCLUSIONS: Adjuvant chemotherapy with TAC, as compared with FAC, significantly improves the rates of disease-free and overall survival among women with operable node-positive breast cancer.

Adult↗
PubMed2005

A putative human breast stem cell population is enriched for steroid receptor-positive cells.

Breast epithelial stem cells are thought to be the primary targets in the etiology of breast cancer. Since breast cancers mostly express estrogen and progesterone receptor (ERalpha and PR), we examined the biology of these ERalpha/PR-positive cells and their relationship to stem cells in normal human breast epithelium. We employed several complementary approaches to identify putative stem cell markers, to characterise an isolated stem cell population and to relate these to cells expressing the steroid receptors ERalpha and PR. Using DNA radiolabelling in human tissue implanted into athymic nude mice, a population of label-retaining cells were shown to be enriched for the putative stem cell markers p21(CIP1) and Msi-1, the human homolog of Drosophila Musashi. Steroid receptor-positive cells were found to co-express these stem cell markers together with cytokeratin 19, another putative stem cell marker in the breast. Human breast epithelial cells with Hoechst dye-effluxing "side population" (SP) properties characteristic of mammary stem cells in mice were demonstrated to be undifferentiated "intermediate" cells by lack of expression of myoepithelial and luminal apical membrane markers. These SP cells were 6-fold enriched for ERalpha-positive cells and expressed several fold higher levels of the ERalpha, p21(CIP1) and Msi1 genes than non-SP cells. In contrast to non-SP cells, SP cells formed branching structures in matrigel which included cells of both luminal and myoepithelial lineages. The data suggest a model where scattered steroid receptor-positive cells are stem cells that self-renew through asymmetric cell division and generate patches of transit amplifying and differentiated cells.

Analysis of Variance↗