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Biomedical subjects

Anthony Howell

Publications and source records attributed to Anthony Howell.

At least 37 records · Page 2Linked to original sources
PubMed2005

Are aromatase inhibitors superior to antiestrogens?

Aromatase inhibitors (AIs) have been in use to treat metastatic breast cancer for over 25 years. Recently potent and specific AIs have been introduced, which, because of their low toxicity profile, are being used in the adjuvant and neoadjuvant situation and also for the prevention of breast cancer. The two non-steroidal AIs, anastrozole and letrozole, and the steroidal AI, exemestane, have all shown superiority to tamoxifen as first-line treatment for advanced breast cancer. Interestingly, the oestrogen receptor downregulator, fulvestrant, was shown to be equivalent to anastrozole when compared as second-line therapy after the failure of tamoxifen. The first adjuvant AI trial began in 1996 and recruited over 9000 patients (ATAC trial). Anastrozole was compared with tamoxifen and a combination of the two drugs. There were no significant differences between tamoxifen and the combination. However, anastrozole showed about a 20% improvement in disease-free survival in ER+ disease compared with the other treatments. An overall survival analysis will be reported later this year. Two trials have compared 5 years of tamoxifen with 2-3 years of tamoxifen, followed by 2-3 years of AI (one trial (ITA) used anastrozole and another (intergroup) exemestane). Both trials show a disease-free advantage for the switch to AI. In another study (MA17) 5 years of tamoxifen was followed by a randomisation to letrozole or placebo and showed a significant disease-free advantage to the AI. Both letrozole and anastrozole show superiority to tamoxifen when used as a neoadjuvant therapy. Anastrozole significantly reduced contralateral breast cancer compared with tamoxifen, and this has led to two prevention trials: one in women at risk comparing anastrozole with placebo and the other after excision of DCIS comparing anastrozole with tamoxifen (IBIS II). The NCI Canada has also just initiated a trial of exemestane for prevention. Nearly all data available indicate that AIs are superior to tamoxifen. The important question is whether survival is improved when they are used as adjuvant therapy?

Aromatase Inhibitors↗
PubMed2005

Vascular effects of aromatase inhibitors: data from clinical trials.

Aromatase inhibitors (AIs) are becoming the endocrine treatment of first choice for postmenopausal women with hormone receptor-positive breast cancer and are under investigation for use in breast cancer prevention. AIs reduce circulating estrogen to barely detectable concentrations. It is possible that such a low concentration will be deleterious to the vascular system since estrogen receptors are known to be in the cell walls of blood vessels and estrogen is thought to be important in maintaining blood vessel integrity. Because most women who present with primary breast cancer are cured by surgery and systemic therapy and the major cause of female death is vascular disease, it is particularly important to investigate the vascular side effects of AIs in current breast cancer adjuvant and prevention trials. In order to set the vascular toxicities of AIs reported in the current adjuvant trials into context, here we compare them with the toxicities seen during treatment with hormone replacement therapy (HRT) and selective estrogen receptor modulators (SERMs). Clinical trial evidence indicates that HRT increases risk of coronary heart disease (CHD) whereas SERMs and AIs (to date) appear to be neutral. Cerebrovascular disease and venous thromboembotic events are increased by HRT and SERMs but appear to be unaffected by treatment with AIs. Cognitive function is also considered here since it may also have a vascular component and is potentially a serious potential side effect/benefit of AIs. Recent studies indicate that HRT has a small detrimental effect on cognitive function and is associated with a doubling of the incidence of dementia. A comprehensive study of the SERM, raloxifene, on cognitive function showed no significant effect. There are no definitive reported studies investigating tamoxifen and none for AIs on cognitive function, although there is one in progress in the context of the IBIS II prevention trial which compares anastrozole to placebo in women at high risk. At present concerns about deleterious vascular side effects are confined to HRT and SERMs. However, we have few long-term data using AIs for the treatment and prevention of breast cancer.

Antineoplastic Agents, Hormonal↗
PubMed2005

Lung cancer after treatment for Hodgkin's lymphoma: a systematic review.

Developments in modern chemotherapy and radiotherapy mean that most patients with Hodgkin's lymphoma can now be cured. However, the long-term effects of anticancer treatment include an increased risk of a second malignant disease. We have done a systematic review of studies reporting long-term complications of the treatment of Hodgkin's lymphoma published in English since 1985. These studies show that risk of lung cancer is significantly increased in patients treated for Hodgkin's lymphoma, with a reported mean relative risk of 2.6-7.0 and a significantly increased absolute excess risk. The absolute excess risk increases with time from treatment, for as long as 20-25 years, and is highest in patients treated at age 45 years or older. Both chemotherapy and radiotherapy contribute to the risk, and evidence suggests that the effects are additive. Cigarette smoking seems to multiply the risk associated with both chemotherapy and radiotherapy. In the high-risk group of patients, 50-150 patients per 1000 are expected to develop lung cancer by 10-20 years after treatment. The role of screening in this group of patients has not yet been assessed, but an international study combining CT with genomic and proteomic assessment is planned.

Adolescent↗
PubMed2005

Mechanisms of Disease: prediction and prevention of breast cancer--cellular and molecular interactions.

Breast cancer is the most prevalent female cancer in the world and its incidence is increasing, largely because of the Western lifestyle. There is a need, not only to predict women who will develop the disease, but also to apply drug and lifestyle measures in order to prevent the disease. Current risk prediction models are based on combinations of risk factors and have good predictive but low discriminatory power. New risk prediction methods might come from examination of single nucleotide polymorphisms in several genes or from an increased knowledge of the molecular and cellular biology of the breast, particularly with respect to aberrant gene expression and protein synthesis. These methods might also determine new targets for preventive agents and lifestyle change. Many potential preventive measures are available and some have been successful. New approaches are required, however, not only to prevent the disease but to devise methods for their assessment that do not require very large and expensive clinical trials.

Anticarcinogenic Agents↗
PubMed2005

Selective oestrogen receptor modulators, aromatase inhibitors and the female breast.

PURPOSE OF REVIEW: Tamoxifen has been available for over 20 years and remains the most commonly recognized endocrine therapy. This review was prompted by a wealth of new data on several newer endocrine agents, including selective oestrogen receptor modulators, aromatase inhibitors and a new oestrogen receptor antagonist, fulvestrant, which unlike the selective oestrogen receptor modulators has no oestrogen agonist effects. RECENT FINDINGS: Completed analysis of the 'Arimidex', Tamoxifen, Alone or in Combination trial demonstrated that anastrozole as initial adjuvant therapy significantly improved disease-free survival and time to recurrence compared with tamoxifen, as well as reducing the incidence of contralateral breast cancer deaths. The Italian Tamoxifen Anastrozole trial and the Austrian Breast and Colorectal Cancer Study Group 8/Arimidex Nolvadex 95 trial have indicated that anastrozole may also be beneficial in women who have already received 2-3 years of tamoxifen. Similarly, the Intergroup Exemestane Study demonstrated the efficacy of exemestane in this setting. Women who have completed a full 5-year course of tamoxifen may also benefit from aromatase inhibitor treatment as indicated by the MA 17 trial, which investigated letrozole as extended adjuvant therapy. Fulvestrant is effective in tamoxifen-resistant disease, and phase II trial data suggest that fulvestrant may also be effective following aromatase inhibitor failure. SUMMARY: The introduction of the third-generation aromatase inhibitors has caused a paradigm shift in adjuvant endocrine treatment. Research into the optimal use of selective oestrogen receptor modulators continues and the evidence base for fulvestrant, the first in a new class of endocrine agents, continues to grow, confirming its value in the treatment of hormone-responsive breast cancer.

Aromatase Inhibitors↗
PubMed2005

Association of gain and loss of weight before and after menopause with risk of postmenopausal breast cancer in the Iowa women's health study.

Obesity and adult weight gain are well-established risk factors for postmenopausal breast cancer. Although there are a few studies demonstrating the contribution of adult weight gain to breast cancer risk, whether weight gain during a critical time period is specifically associated with risk, or whether subsequent weight loss among women who have gained weight will reduce the excess risk, is not firmly established. We investigated the association of changes in weight (loss or gain in excess of 5% of body weight) using two risk factor models: (a) age 18 to 30 years and age 30 years to menopause and (b) age 30 years to menopause and after the menopause to the baseline study in 1986 on risk of postmenopausal breast cancer in a prospective cohort of 33,660 postmenopausal women in Iowa. Over 15 years of follow-up, 1,987 cases of breast cancer occurred. Data were analyzed using proportional hazards regression models adjusted for established breast cancer risk factors. The most frequently observed pattern of body weight over time was a consistent increase; these women were observed to have the highest rates of breast cancer and served as the reference category for all comparisons. The lowest-risk groups were (a) women who maintained or lost weight from age 18 to 30 years and then lost weight from age 30 years to menopause [risk ratio (RR), 0.36; 95% confidence interval (95% CI), 0.22-0.60] and (b) women who maintained or lost weight from age 30 years to menopause and then lost weight after the menopause (RR, 0.48; 95% CI, 0.22-0.65). Women who gained weight from age 30 years to menopause but then lost weight after the menopause experienced risk reductions (RR, 0.77; 95% CI, 0.64-0.92) although perhaps slightly smaller in magnitude than women who maintained their weight in both time intervals (RR, 0.63; 95% CI, 0.55-0.73). Women who gained weight from age 18 to 30 years and then lost weight from age 30 years to menopause had comparable risk reductions (RR, 0.61; 95% CI, 0.46-0.8) with women who maintained their weight in both time intervals (RR, 0.73; 95% CI, 0.64-0.84). Women who gained weight during the period from age 30 years to menopause but who had stable weight after menopause had rates similar to the reference group. These data suggest prevention of weight gain between age 18 years and menopause or weight loss and maintenance during these years reduces risk of postmenopausal breast cancer.

Adolescent↗
PubMed2005

Overview of the impact of conventional systemic therapies on breast cancer.

Survival in women with breast cancer is improving in the western world, in part related to improved surgery, radiotherapy and adjuvant systemic therapy. Aromatase inhibitors are superior to tamoxifen in this clinical situation and several studies indicate that taxane-based chemotherapy is superior to non-taxane-based regimens. Herceptin is active alone in HER-2/neu +ve advanced breast cancer and four clinical trials are testing this agent in the adjuvant situation. It seems likely that herceptin will add to conventional therapies and thus will be the paradigm for the introduction of other biological therapies to improve cure rates.

Antibodies, Monoclonal↗
PubMed2005

Defining the roles of aromatase inhibitors in the adjuvant treatment of early-stage breast cancer.

The widespread use of tamoxifen has led to significant improvements in survival for postmenopausal women with early-stage hormone receptor-positive breast cancer; however, approximately 30% of patients die despite receiving tamoxifen as adjuvant treatment. In addition, concerns exist regarding tamoxifen-associated side effects, including endometrial cancer and thromboembolic disease. The development of the third-generation aromatase inhibitors (AIs; anastrozole, exemestane, and letrozole) therefore represented a welcome potential alternative to tamoxifen. Several clinical trials have demonstrated the superiority of AIs over tamoxifen in the adjuvant treatment of postmenopausal women with hormone-sensitive breast cancer, but these trials differ in their design and in the characteristics of their patient populations. This review discusses the different designs of the primary adjuvant, switching, extended adjuvant, and sequencing trials that are investigating the use of AIs in the adjuvant treatment of breast cancer and provides direction regarding how the data from these trials could be used to guide treatment choice. This review also demonstrates why one should not extrapolate results from clinical trials to clinical situations that differ from the clinical trial or from clinical trials investigating a particular AI to clinical situations involving another AI.

Anastrozole↗
PubMed2004

Quality of life of postmenopausal women in the Arimidex, Tamoxifen, Alone or in Combination (ATAC) Adjuvant Breast Cancer Trial.

PURPOSE: To determine the quality of life (QoL) of women participating in the Arimidex, Tamoxifen, Alone or in Combination (ATAC) Adjuvant Breast Cancer Trial during the first 2 years of treatment. PATIENTS AND METHODS: A total of 1,021 women were enrolled onto the QoL subprotocol. All had completed primary treatment (surgery +/- radiotherapy +/- chemotherapy) and were to receive 5 years of adjuvant treatment with anastrozole (n = 335), tamoxifen (n = 347), or a combination (n = 339) of both. Patients completed the Functional Assessment of Cancer Therapy-Breast (FACT-B) plus endocrine subscale (ES) at baseline and 3, 6, 12, 18, and 24 months, or until disease recurrence. The primary end point was the FACT-B Trial Outcome Index (TOI). The secondary end point was the ES total score. Analyses of individual endocrine symptoms were also explored. RESULTS: Questionnaire completion approximated 85% of assessments available for analysis. Overall QoL for all groups improved from baseline during the 2-year period. There were no significant differences in TOI or ES scores across treatment groups. Endocrine symptoms increased between baseline and 3 months for all groups and stabilized thereafter. There were some small differences in side effect profiles. Compared with patients receiving tamoxifen only, patients receiving anastrozole only reported significantly fewer cold sweats and vaginal discharge, yet more vaginal dryness, painful intercourse, and loss of sexual interest. CONCLUSION: Two years of treatment with anastrozole, tamoxifen, or the combination had a similar overall QoL impact, showing gradual improvement over time. Endocrine-related symptoms for all three arms worsened initially and recovered partially during 2 years. The different symptoms experienced may assist in decision making about treatment and supportive care needs.

Anastrozole↗
PubMed2004

An early peak of relapse after surgery for breast cancer.

There is great interest among oncologists concerning what we might learn by examining the pattern of relapse after breast cancer surgery. What you see depends upon how hard you look. Up to now, investigators have examined the hazard ratio for relapse every 6-12 months. In a research paper, published in this issue of Breast Cancer Research, the Milan group have looked at the hazard ratio every three months and have found, for the first time, a distinct, very early peak of relapse in a group of premenopausal, node-positive patients not given chemotherapy or hormone therapy. What is now needed is for other groups to repeat this observation and, if found, to examine the characteristics of the tumours producing this phenomenon in order to develop hypotheses about its cause and possible treatments.

Breast Neoplasms↗
PubMed2004

Endocrinology and hormone therapy in breast cancer: aromatase inhibitors versus antioestrogens.

Endocrine therapies act by either blocking or downregulating the oestrogen receptor or by reducing oestrogen concentrations around and within the cancer cell. In postmenopausal women, oestrogen suppression is achieved by inhibition of the enzyme aromatase by aromatase inhibitors (AIs). Modern AIs (anastrozole, letrozole and exemestane) are more potent than earlier ones and suppress oestradiol levels in plasma to virtually undetectable concentrations. Recent comparisons of AIs with the most widely used oestrogen receptor blocking drug tamoxifen indicate that, in general, AIs result in increased response rates and greater durations of response. Here, we summarize data supporting the difference between the two types of treatment and attempt to account for the underlying mechanisms that favour AIs.

Animals↗
PubMed2004

Comparison of fulvestrant versus tamoxifen for the treatment of advanced breast cancer in postmenopausal women previously untreated with endocrine therapy: a multinational, double-blind, randomized trial.

PURPOSE: To evaluate the efficacy and tolerability of fulvestrant (Faslodex; AstraZeneca Pharmaceuticals LP, Wilmington, DE), a new estrogen receptor (ER) antagonist that downregulates ER and has no agonist effects, versus tamoxifen, an antiestrogen with agonist and antagonist effects, for the treatment of advanced breast cancer in postmenopausal women. PATIENTS AND METHODS: In this multicenter, double-blind, randomized trial, patients with metastatic/locally advanced breast cancer previously untreated for advanced disease were randomly assigned to receive either fulvestrant (250 mg, via intramuscular injection, once monthly; n = 313) or tamoxifen (20 mg, orally, once daily; n = 274). Patients' tumors were positive for ER (ER+) and/or progesterone receptor (PgR+), or had an unknown receptor status. RESULTS: At a median follow-up of 14.5 months, there was no significant difference between fulvestrant and tamoxifen for the primary end point of time to progression (TTP; median TTP, 6.8 months and 8.3 months, respectively; hazard ratio, 1.18; 95% CI, 0.98 to 1.44; P =.088). In a prospectively planned subset analysis of patients with known ER+ and/or PgR+ tumors ( approximately 78%), median TTP was 8.2 months for fulvestrant and 8.3 months for tamoxifen (hazard ratio, 1.10; 95% CI, 0.89 to 1.36; P =.39). The objective response rate for the overall population was 31.6% with fulvestrant and 33.9% with tamoxifen, and 33.2% and 31.1%, respectively, in the known hormone receptor-positive subgroup. Both treatments were well tolerated. CONCLUSION: In the overall population, between-group differences in efficacy end points favored tamoxifen, and statistical noninferiority of fulvestrant could not be demonstrated. However, in patients with hormone receptor-positive tumors, fulvestrant had similar efficacy to tamoxifen and was well tolerated.

Administration, Oral↗
PubMed2004

Does hormone therapy for the treatment of breast cancer have a detrimental effect on memory and cognition? A pilot study.

This pilot study examines whether hormone therapy for breast cancer affects cognition. Patients participating in a randomised trial of anastrozole, tamoxifen alone or combined (ATAC) (n=94) and a group of women without breast cancer (n=35) completed a battery of neuropsychological measures. Compared with the control group, the patients were impaired on a processing speed task (p=0.032) and on a measure of immediate verbal memory (p=0.026) after controlling for the use of hormone replacement therapy in both groups. Patient group performance was not significantly related to length of treatment or measures of psychological morbidity. The results showed specific impairments in processing speed and verbal memory in women receiving hormonal therapy for the treatment of breast cancer. Verbal memory may be especially sensitive to changes in oestrogen levels, a finding commonly reported in studies of hormone replacement therapy in healthy women. In view of the increased use of hormone therapies in an adjuvant and preventative setting their impact on cognitive functioning should be investigated more thoroughly.

Affect↗
PubMed2004

The use of selective estrogen receptor modulators and selective estrogen receptor down-regulators in breast cancer.

Tamoxifen is one of the most effective treatments for breast cancer through its ability to antagonize estrogen-dependent growth by binding estrogen receptors (ERs) and inhibiting proliferation of breast epithelial cells. However, tamoxifen has estrogenic agonist effects in other tissues such as bone and endometrium due to liganded ER activating target genes in these different types of cell. Several novel anti-estrogen compounds have been developed which have a reduced agonist profile on breast and gynaecological tissues. These compounds offer the potential for enhanced efficacy and reduced toxicity compared with tamoxifen. In advanced breast cancer clinical data exist for two groups of agents: the selective estrogen receptor modulators (SERMs), further divided into "tamoxifen-like" (e.g. toremifene, droloxifene and idoxifene) and "fixed ring" compounds (e.g. raloxifene, arzoxifene and EM-800), and the selective estrogen receptor down-regulators (SERDs; e.g. fulvestrant (ICI 182780), SR 16234 and ZK 191703) also termed "pure anti-estrogens". In phase II trials in tamoxifen-resistant metastatic breast cancer the SERMs show low objective response rates (range 0-15%), suggesting cross resistance with tamoxifen. Randomized phase III trials for toremifene and idoxifene in over 1500 patients showed no significant difference compared with tamoxifen. Fewer clinical data exist for the "fixed ring" SERMs and it remains unclear whether any clinical advantage exists for the "fixed ring" SERMs over tamoxifen as first-line therapy. The main advantage for SERMs such as tamoxifen and raloxifene probably remains in early-stage disease (adjuvant therapy or prevention). Fulvestrant and the other SERDs have a high affinity for the estrogen receptor (ER) compared to tamoxifen, but none of its agonist activities. Of the SERDs, only fulvestrant has entered the clinic and this new agent is showing promising clinical activity in the treatment of advanced breast cancer. Recently published phase III studies have shown fulvestrant to be at least as effective as the third-generation aromatase inhibitor anastrozole in patients whose disease has relapsed or progressed on prior endocrine therapy. Surprisingly, however, in a phase III trial versus tamoxifen for the first-line therapy of advanced breast cancer fulvestrant did not attain the requirements for equivalence to tamoxifen, and in terms of time-to-treatment failure was inferior (5.9 versus 7.8 months for fulvestrant and tamoxifen, respectively; P=0.029). Future clinical studies will evaluate fulvestrant in the neoadjuvant setting together with its optimal sequencing in relation to tamoxifen and other endocrine therapies in advanced disease.

Antineoplastic Agents, Hormonal↗
PubMed2004

Steroid receptors in human breast cancer.

Ovarian steroids, acting through nuclear receptors, are crucial players in normal breast development and cancer. Estrogen, in particular, is the focus of breast cancer therapies because tumours are often dependent on this steroid for growth. Recently, novel genes and/or protein isoforms of receptors for both estrogen and progesterone have been discovered, leading us to reappraise their roles in breast development and cancer. Recognition of changes in estrogen receptor biology that occur in the transition from normal development to cancer has emphasized its contribution to tumorigenesis. In addition, complex interactions with other signalling pathways, particularly growth factor pathways, have recently come to the forefront. These interactions might explain resistance to endocrine treatments and offer solutions in terms of novel therapeutic targets.

Breast Neoplasms↗
PubMed2004

Are BRCA1- and BRCA2-related breast cancers associated with increased mortality?

There has been contradictory evidence as to whether BRCA1 associated breast cancers have a poorer prognosis than non-BRCA1 cancers. In this issue of Breast Cancer Research Robson and colleagues provide further evidence for poorer survival in BRCA1 carriers and show that it could be attributed to failure to treat small node-negative grade 3 breast cancers with chemotherapy. There still remains little evidence for a survival difference for BRCA2 related breast cancers. Although the high contralateral breast cancer risk is confirmed by this study there is no real evidence for an increase in ipsilateral recurrence or new primary breast cancers in mutation carriers up to the 10-year point.

BRCA1 Protein↗