Comparative trial of nafoxidine and ethinyloestradiol in advanced breast cancer: an E.O.R.T.C. study.

A randomized clinical trial of nafoxidine, a non-steroidal oestrogen antagonist, and ethinyloestradiol in postmenopausal patients with advanced breast cancer produced objective remissions in 31% of 49 women receiving nafoxidine and in 14% of 49 receiving ethinyloestradiol. The differences in remission rates was almost significant (0.05 less than P less than 0.10). Life-threatening complications were more frequent with ethinyloestradiol than with nafoxidine but the latter produced specific toxic reactions on skin and hair that may limit its practical usefulness. Synthetic oestrogen antagonists may occupy a privileged place in the treatment of breast cancer, and other representatives of this new class of compounds should be accurately assessed in randomized clinical trials.     

The relationship between aromatase in primary breast tumors and response to treatment with aromatase inhibitors in advanced disease

Aromatase inhibitors are proving to be more effective than tamoxifen for postmenopausal patients with breast cancer. Estrogen concentrations in the breast are similar in both premenopausal and postmenopausal women, and several fold higher than circulating levels in postmenopausal women. In order to investigate the importance of intratumoral aromatase in stimulating the proliferation of the tumor, we used immunocytochemistry to determine the extent of aromatase expression in relationship to the response of the patient to aromatase inhibitor treatment. The relationship between positive staining for aromatase in the primary tumor and response to treatment with an aromatase inhibitor was investigated in a retrospective study of 102 patients with advanced breast cancer. Immunohistochemical staining using a monoclonal antibody against aromatase was performed on paraffin embedded tumor tissue. Response was evaluated using UICC criteria. Nine out of 13 patients with objective response to treatment stained positive and 49 of 89 patients with stable or progressive disease stained positive. No significant relationship between positive staining and objective response to treatment could be found. When patients with 'clinical benefit' (i.e. objective response plus prolonged stable disease of at least 6 months) were considered, also no relationship could be found. Further analysis of subgroups with positive hormone receptors, treatment with newer generation aromatase inhibitors, single metastatic site, non-visceral metastases and previous treatment only with tamoxifen did not show any relationship. Tumor aromatase expression did not correlate with response of patients with advanced breast cancer to aromatase inhibitor treatment. Most patients had relapsed from other treatments before receiving an aromatase inhibitor. It seems likely that many of these patients had tumors that may have progressed to hormone independence at this stage of the disease. Research in patients who have received treatment with aromatase inhibitors in earlier stages of disease (first line and adjuvant treatment) may provide further information on the relationship between tumor aromatase, steroid receptors and response to inhibitor treatment.     

Controlled clinical trial of L-dopa and nafoxidine in advanced breast cancer: an E.O.R.T.C. study.

L-Dopa lowers plasma prolactin levels, and there have been reports that patients with advanced breast cancer have been successfully treated with L-dopa. To test the potential value of L-dopa in this disease a randomized clinical trial of L-dopa and nafoxidine (as the reference compound) was conducted in postmenopausal women with advanced breast cancer. Objective remissions were obtained in sever out of 36 patients (19%) treated with nafoxidine but in none out of 40 patients treated with L-dopa. L-Dopa in the dose schedule used seems to be ineffective in advanced breast cancer.     

Tamoxifen versus aminoglutethimide in advanced breast carcinoma: a randomized cross-over trial.

Altogether 117 patients with advanced breast cancer were treated with either tamoxifen 10 mg by mouth twice daily or aminoglutethimide 250 mg by mouth four times daily with hydrocortisone 20 mg twice daily in a randomised cross-over trial in which patients who failed to respond to the first treatment or relapsed while receiving it were switched to the other. Eighteen (30%) out of 60 patients initially treated with tamoxifen achieved an objective response and 11 (18%) showed stable disease. Seventeen (30%) out of 57 patients treated initially with aminoglutethimide achieved an objective response and 13 (23%) achieved stable disease. Objective responses in bone metastases were achieved more commonly with aminoglutethimide (11 patients (35%)) than with tamoxifen (five (17%)). The predicted median duration of response for tamoxifen was 15 months and for aminoglutethimide over 15 months (no significant difference). Five (15%) out of 34 patients who failed to respond to tamoxifen and four out of six patients who relapsed after responding to tamoxifen subsequently responded to aminoglutethimide. In contrast, only two (6%) out of 31 patients who failed to respond to aminoglutethimide and none out of four patients who relapsed while receiving aminoglutethimide subsequently responded to tamoxifen. The main side effects occurring in the 97 patients who received aminoglutethimide as first- or second-line treatment were lethargy and drowsiness (36 patients) and rash (29); seven patients had to stop treatment because of side effects. In contrast, side effects were rare and mild with tamoxifen and no patient had to stop treatment because of them. Both tamoxifen and aminoglutethimide appeared from this study to be equally effective in the medical endocrine treatment of advanced breast cancer.     

Bias in Observational Studies of the Association between Menopausal Hormone Therapy and Breast Cancer

BackgroundDuring the period 1985-2000 the breast cancer incidence rates increased 50% in the age group invited to mammography screening in Norway and Sweden. Simultaneously, use of hormone replacement treatment therapy (HT) increased 5 times. Several influential observational studies showed that HT was associated with 50% to 100% increased risk of breast cancer and most for those using combined (estrogen plus progestin) hormone replacement therapy (CHT). In contrast, the randomized WHI trial reported that CHT increased the risk by 10% for those not having previously used hormones and 24% when including previous users in the analyses. In another randomized trial, estrogen use only was not associated with any increased risk at all. After the WHI trial was published in 2003, use of HT dropped 70% within 5 years in Norway and Sweden while breast cancer rates were essentially unchanged. After 2008, HT use has dropped further and breast cancer incidence rates have started increasing again. The study objective is to calculate and to explain potential bias in the observational study design.ConclusionsWe suggest that the mechanism causing higher hazard ratio of breast cancer (compared to the observational studies) is the time-varying effect of CHT on the breast cancer risk and selective retrospective reporting of hormone use. Other risk factors for the increase in breast cancer risk in the age group 50-69 years should be considered, for example, overdiagnosis.     

Postoperative radiotherapy and late mortality: evidence from the Cancer Research Campaign trial for early breast cancer.

OBJECTIVE--To identify any excess mortality caused by adjuvant radiotherapy for early breast cancer. DESIGN--Prospective randomised clinical trial. Two thousand subjects needed for study to have a 90% chance of detecting a difference in survival rate of 7% with 95% significance. Patients were followed up until June 1988, giving follow up of 158-216 months. SETTING--A multicentre trial mainly drawing patients from centres in the United Kingdom. PATIENTS--2800 Women presenting with clinical stage I or II carcinoma of the breast from June 1970 to April 1975. INTERVENTIONS--One group of women (n = 1376) had simple mastectomy followed by immediate postoperative radiotherapy (1320 to 1510 rets). The remaining women (n = 1424) had simple mastectomy with subsequent careful observation of the axilla, radiotherapy being delayed until there was obvious progression or recurrence of disease locally. END POINT--Increased mortality in patients treated with radiotherapy from causes other than breast cancer. MEASUREMENTS AND MAIN RESULTS--Survival was measured from time of first treatment to death or last follow up. Deaths from any cause and from specified causes were counted as events. Comparison over the whole follow up showed a slight excess mortality in the group treated with radiotherapy (relative risk 1.04; 95% confidence interval 0.94 to 1.15). The relative risk of death from breast cancer was 0.97 (0.87 to 1.08) but that of death from other causes was 1.37 (1.09 to 1.72), the increase mainly being in women who had had tumours of the left breast (1.61 (1.17 to 2.24)) and had been treated with orthovoltage (1.85 (1.27 to 2.71)). Analysis of causes of death after five years showed a relative risk of 2.11 (1.25 to 3.59) for new malignancies and of 1.65 (1.05 to 2.58) for cardiac disease, the increase in cardiac mortality being most pronounced in patients who had had tumours of the left breast and whose treatment had included orthovoltage radiation (relative risk 2.67 (1.28 to 5.55)). CONCLUSIONS--Adjuvant radiotherapy after simple mastectomy for early breast cancer produces a small excess late mortality from other cancers and cardiac disease. The risk has to be balanced against the higher risk of local recurrence when immediate postoperative radiotherapy is not given. The balance has to be assessed for each patient, and for many patients radiotherapy will still be desirable in the initial treatment of their early breast cancer.     

Predictors of response to aromatase inhibitors

Aromatase inhibitors are now considered to be part of the endocrine treatment for most hormone receptor-positive breast cancer in post-menopausal women for both early and advanced disease. Despite the impressive efficacy of these agents, up to 50% of treated patients exhibit de novo or intrinsic resistance to aromatase inhibitors and hence identification of response predictors is essential to allow treatment to be directed towards responsive populations and for alternative or additional therapies to be offered to resistant patients. Emerging data seem to suggest a role for the conventional tumour markers of oestrogen receptor and progesterone receptor as possible predictors of response but, particularly in the adjuvant setting, the extent to which these are useful has not been fully elucidated. Data from both the neo-adjuvant and advanced disease settings suggest that response to aromatase inhibitors does not appear to be adversely affected by HER-2 overexpression. Within neo-adjuvant aromatase inhibitor studies, the proliferation marker Ki67 has shown a significant correlation with relapse-free survival, suggesting a role in prediction for measurement of Ki67 and other dynamic markers of response. Analysis of multiple gene expression changes over a short treatment period may also have potential clinical utility for prediction of response.     

A follow-up study of 105 women with breast cancer following reduction mammaplasty.

Reduction mammaplasty is one of the most common procedures performed by plastic surgeons in Canada. In a recent study of 27,500 women in the province of Ontario who underwent breast reduction surgery, 105 women were identified who developed breast cancer after reduction mammaplasty. The purpose of this study was to compare women who had breast cancer and had a previous breast reduction with women who had breast cancer but did not have a breast reduction. Specifically, we wanted to document patient demographics, cancer type, surgical and nonsurgical treatment, and eventual outcome. A comparison group of non-breast reduction women was taken from the cohort of breast cancer patients in the province of Ontario, and the two groups were matched for age, year of diagnosis, and place of diagnosis. It was found that (1) the average age at diagnosis of breast cancer is significantly younger for women who have had previous breast reduction surgery than for those who have not; (2) the median interval between breast reduction and cancer is 5 years; (3) the type, location, and side of breast cancers are similar in the two groups of women; (4) breast reduction does not significantly increase or decrease survival rate from breast cancer; and (5) women who have had breast reduction receive the same treatment for their breast cancer as women who have not had reduction mammaplasty.     

Cancer chemotherapy-induced lymphocytosis: a revolutionary discovery in the medical oncology

The recent advances in the investigation of tumor immunobiology have suggested that cancer chemotherapy, in addition to its well known cytotoxic activity, may play modulatory effects on the endogenous production of cytokines involved in the control of both tumor angiogenesis and antitumor immunity. Cancer chemotherapy constantly acts with inhibitory effects on anti-bacterial, anti-viral and anti- mycotic immune responses, whereas its action on anticancer immunity, which is mainly mediated by lymphocytes, has still to be better investigated and defined. The present study was carried out to evaluate the influence of chemotherapy on lymphocyte count and its relation to the clinical response in cancer patients suffering from the most commonly frequent tumor histotypes, including lung, colorectal, breast and prostate carcinomas. The study included 144 consecutive metastatic solid tumor patients. Lung cancer patients were treated with cisplatin plus gemcitabine, colorectal cancer patients received oxaliplatin plus 5-fluorouracil, while those affected by breast cancer or prostate carcinoma were treated with taxotere alone. An objective tumor regression was achieved in 66 out of 144 (46 percent) patients, whereas the remaining 78 patients had only a stable disease (SD)or a progressive disease. Independently of tumor histotype and chemotherapeutic regimen, a lymphocytosis occurred in patients who achieved an objective tumor regression in response to chemotherapy, and lymphocyte mean count observed at the end of the chemotherapeutic treatment was significantly higher with respect to the values seen before the onset of treatment. On the contrary, lymphocyte mean number decreased on chemotherapy in patients with SD or PD, even though the decline was statistically significant with respect to the pretreatment values in the only patients who had a PD in response to chemotherapy. This study would suggest that chemotherapy itself may paradoxically act, at least in part, as a cancer immunotherapy by inducing lymphocytosis, as well as previously demonstrated for the only immunotherapy with IL-2, probably by modulating the cytokine network and correcting the altered endogenous production of cytokines, responsible for cancer-related immunodeficiency.     

The consequences of exhaustive antiestrogen therapy in breast cancer: estrogen-induced tumor cell death

Forty years ago, the endocrine treatment for breast cancer was a last resort at palliation before the disease overwhelmed the patient (1). Ovarian ablation was the treatment of choice for the premenopausal patient, whereas either adrenalectomy or, paradoxically, high-dose synthetic estrogen therapy were used for treatment in postmenopausal patients. A reduction or an excess of estrogen provoked objective responses in one out of three women. Unfortunately, there was no way of predicting who would respond to endocrine ablation, and because so few patients responded there was no enthusiasm for developing new endocrine agents. All hopes for a cure for breast cancer turned to appropriate combinations of cytotoxic chemotherapy. Today tamoxifen, a nonsteroidal antiestrogen (2), has proven to be effective in all stages of premenopausal and postmenopausal breast cancer, and several new endocrine strategies, including aromatase inhibitors, luteinizing-hormone releasing hormone (LHRH) superagonists, and a pure antiestrogen (fulvestrant), are now available for breast cancer treatment. Additionally, tamoxifen and raloxifene, a related compound, are used to reduce the risk of breast cancer and osteoporosis, respectively, in high-risk groups (3). Hormonal modulation and strategies to prevent the actions of estrogen in the breast are ubiquitous. However, with successful changes in treatment strategies comes the consequence of change. This minireview will describe the current strategies for the treatment and prevention of breast cancer and present emerging new concepts about the consequences of exhaustive antiestrogen treatment on therapeutic resistance.     

Importance of PI3-kinase pathway in response/resistance to aromatase inhibitors

Endocrine therapy has been the most effective treatment modality for hormone receptor positive breast cancer. However, its efficacy has been limited by either de novo or acquired resistance. Recent data indicates that activation of the phosphatidylinositol 3-kinase (PI3K) signaling is associated with the poor outcome luminal B subtype of breast cancer and accompanied by the development of endocrine therapy resistance. Importantly, inhibition of PI3K pathway signaling in endocrine resistant breast cancer cell lines reduces cell survival and improves treatment response to endocrine agents. Interestingly, mutations in PIK3CA, the alpha catalytic subunit of the class IA PI3K, which renders cells dependent on PI3K pathway signaling, is the most common genetic abnormality identified in hormone receptor positive breast cancer. The synthetic lethality observed between estrogen deprivation and PI3K pathway inhibition in estrogen receptor positive (ER+) breast cancer cell lines provides further scientific rational to target both estrogen receptor and the PI3K pathway in order to improve the outcome of ER+ breast cancer.     

曲妥珠单抗辅助或新辅助治疗HER2 阳性转移性乳腺癌的临床结果

目的:比较人表皮生长因子受体2过表达(HER2+)的患者既往接受以曲妥珠单抗为基础辅助或新辅助治疗后再次接受针曲妥珠单抗治疗的临床结果。方法:共247例(I-III期170例,IV期77例)HER2+转移性乳腺癌患者,其中首次接受曲妥珠单抗治疗患者211例(I-III期134例,IV期77例),再次接受曲妥珠单抗治疗患者36例(I-III期)。使用Cox比例风险回归和logistic回归分析首次或提前接受曲妥珠单抗治疗的患者的预后的临床结果,生存评估使用Kaplan-Meier法。结果:I-III期HER2+转移性乳腺癌患者中,未预先接受曲妥珠单抗治疗组的中位总生存期为36个月和预先接受曲妥珠单抗治疗组为28个月(危害比[HR],1.45;95%CI,1.05-2.02[P=0.012]);I-IV期HER2+转移性乳腺癌患者中,未预先使用曲妥珠单抗组的中位总生存期为37个月,客观缓解率58%;临床获益率77%;预先使用曲妥珠单抗组为25个月,客观缓解率28%;临床获益率37%;调整后的比值比为客观缓解率0.37(9%CI,0.18-0.77;P=0.010)和临床获益率0.28(95%CI,0.14-0.59;P=0.014)。单因素分析没有提前接受曲妥珠单抗治疗组中位总生存率较长(P=0.012)。多因素分析发现总生存率没有显著差异(P=0.19)。结论:当曲妥珠单抗用于转移性疾病,没有提前接受曲妥珠单抗治疗的HER2+乳腺癌患者临床结果优于提前接受曲妥珠单抗治疗的患者。     

Value of the history in the office diagnosis of breast cancer.

A review of the histories of 1059 patients with breast problems seen consecutively in office consultation revealed an incidence of breast cancer of 13%. Patients over 50 years of age or whose mother or sister had had breast cancer had a substantially greater likelihood of having breast cancer. The finding of the problem on routine examination, a family history of breast cancer in a relative other than the mother or a sister, or prominent breast pain or nipple discharge made the diagnosis of cancer less likely. Menstrual status, a history of previous benign disease, nulliparity, current hormone therapy and duration of symptoms did not help identify the patient likely to have breast cancer. Much time could be saved for both doctor and patient in taking the history from patients with breast disorders. Only the patient''s age and the history of the mother and sisters with regard to breast cancer will help identify the "high-risk" patient. Other historical findings are either valueless or should be used to reassure these usually anxious women.     

Dermatomyositis as paraneoplastic syndrome of peritoneal and ovarian relapse after long-term complete remission in patient with metastatic bilateral breast cancer

Dermatomyositis is a rare disease characterised by inflammatory muscle affection and characteristic cutaneous changes. When occuring in a patient with cancer, dermatomyositis may indicate recurrence or progression and poor outcome. Herein, the treatment of metastatic breast cancer, metastatic pattern, characteristics of long-term survivors, and link between dermatomyositis and breast cancer are discussed and the literature reviewed. We report a 57-year old female patient with metastatic bilateral breast cancer whose ovarian and peritoneal relapse after long-term remission was disclosed by occurence of paraneoplastic dermatomyositis. The patient previously had a 15-year long disease free-period after primary treatment for breast cancer before onset of pulmonary dissemination. Following antracycline-based chemotherapy, the complete remission lasting another 15 years was accomplished. Dermatomyositis had been resolved upon induction of second-line taxane-based chemotherapy. After completion of six cycles of gemcitabine and paclitaxel chemotherapy, check-up revealed further progression. The patient subsequently underwent six cycles of third-line CAP chemotherapy (cyclofosfamide, doxorubicine, cisplatin) but disease progressed and oral capecitabine chemotherapy was initiated. The patient received four cycles of capecitabine followed by further vast progression and finally expired following massive pulmonary embolism. Our case stresses the need of thorough staging and check-up when dermatomyositis arises in patients with breast cancer, regardless of previous stable long-term complete remission. Furthermore, we believe that treatment with curative intent in young patients with metastatic breast cancer, who have good performance statuses and no comorbidities is required, because it is more likely to produce long-term complete remission. However, following disease relapse a poor outcome can be expected.     

Concurrent or sequential use of cytotoxic chemotherapy and hormone treatment in advanced breast cancer: report of the Swiss Group for Clinical Cancer Research.

In a trial of combined hormone treatment and cytotoxic chemotherapy 464 patients with advanced breast cancer were randomly allocated to either concurrent or sequential treatment. Cytotoxic drugs were given only if the antitumour activity of the hormone treatment was inadequate. Hormone treatment consisted of oophorectomy for premenopausal and tamoxifen administration for postmenopausal patients. Length of survival was better, though not significantly, in premenopausal patients (p = 0.29) treated concurrently and in postmenopausal women (p = 0.17) treated sequentially; the difference was highly significant (p = 0.003) only for postmenopausal women in the low-risk category. The findings suggest that postmenopausal women with metastatic breast cancer should probably be treated primarily by carefully monitored hormone treatment.     

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.     

Clinical practice guidelines for the care and treatment of breast cancer: 14. The role of hormone replacement therapy in women with a previous diagnosis of breast cancer

Objective

To provide information and recommendations to women with a previous diagnosis of breast cancer and their physicians regarding hormone replacement therapy (HRT).

Outcomes

Control of menopausal symptoms, quality of life, prevention of osteoporosis, prevention of cardiovascular disease, risk of recurrence of breast cancer, risk of death from breast cancer.

Evidence

Systematic review of English-language literature published from January 1990 to July 2001 retrieved from MEDLINE and CANCERLIT.

Recommendations

· Routine use of HRT (either estrogen alone or estrogen plus progesterone) is not recommended for women who have had breast cancer. Randomized controlled trials are required to guide recommendations for this group of women. Women who have had breast cancer are at risk of recurrence and contralateral breast cancer. The potential effect of HRT on these outcomes in women with breast cancer has not been determined in methodologically sound studies. However, in animal and in vitro studies, the development and growth of breast cancer is known to be estrogen dependent. Given the demonstrated increased risk of breast cancer associated with HRT in women without a diagnosis of breast cancer, it is possible that the risk of recurrence and contralateral breast cancer associated with HRT in women with breast cancer could be of a similar magnitude. · Postmenopausal women with a previous diagnosis of breast cancer who request HRT should be encouraged to consider alternatives to HRT. If menopausal symptoms are particularly troublesome and do not respond to alternative approaches, a well-informed woman may choose to use HRT to control these symptoms after discussing the risks with her physician. In these circumstances, both the dose and the duration of treatment should be minimized.

Validation

Internal validation within the Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer; no external validation.

Sponsor

The steering committee was convened by Health Canada.

Completion date

October 2001.Hormone replacement therapy (HRT) connotes treatment with either estrogen alone or estrogen with progesterone in postmenopausal women. Menopausal symptoms, such as hot flashes and vaginal dryness, and the potential long-term effects of estrogen deprivation are a concern to women with breast cancer, particularly those in whom menopause develops early as a result of adjuvant chemotherapy.Traditionally, the use of HRT has been contraindicated in women with breast cancer because of the notion that the development and growth of breast cancer is estrogen dependent and that the introduction of HRT may increase the risk of breast cancer recurrence. The focus of this guideline is on whether it is safe to give HRT to women with breast cancer.     

Aromatase inhibitors in the treatment of breast cancer

A number of inhibitors of estrogen synthesis are now becoming available which could be of value in the treatment of breast cancer. 4-Hydroxyandrostenedione (4-OHA), the first of these compounds to enter the clinic has been found to be effective in postmenopausal patients who have relapsed from tamoxifen. Thus, in studies of 240 patients, 26% patients experienced partial or complete response to treatment. An additional 25% patients had disease stabilization. 4-OHA is a potent selective, steroidal inhibitor which causes inactivation of aromatase in vitro. It is effective in reducing concentrations of ovarian estrogens in rats and of ovarian and peripheral estrogens in non-human primate species. The compound has been shown to lower serum estrogen levels in postmenopausal breast cancer patients. However, not all of these patients experienced disease remission, suggesting that their tumors were hormone insensitive rather than that the dose of 4-OHA was suboptimal. In trials of patients who had not received prior tamoxifen treatment, 4-OHA (250 mg i.m. every 2 weeks) was found to induce complete or partial tumor regression in 33% of patients. The response of patients was not significantly different from that observed in patients treated with tamoxifen (30 mg o.d) of 37%. No significant difference between treatments was observed for disease stabilization, the duration of response or median survival. Several other steroidal aromatase inhibitors have been studied, such as 7-substituted androstenedione derivatives. MDL 18962 [10-(2-propynyl)estr-4-ene-3,17-dione] and FCE 24304 (6-methylen-androsta-1,4-diene-3,17-dione) are currently in clinical trials. Non-steroidal inhibitors of cytochrome P-450 enzymes, such as imidazole and triazole derivatives have been developed which are highly selective for aromatase. Three triazoles which are very potent and selective inhibitors are vorazole (6-[(4-chlorophenyl)(1H-1,2,4-triazol-1-yl)-methyl]1-methyl-1H-benzotriazole R 76713, arimidex 2,2′[5-( -1,2,4-triazol-1-yl methyl)-1,3-phenylene]bis(2-methylpropiononitrile) (ZD1033) and letrozole 4-[1-(cyanophenyl)-1-(1,2,4-triazolyl)methyl]benzonitril (CGS 20267). These compounds reduce serum estradiol concentration to undetectable levels in breast cancer patients. These highly potent inhibitors provide the opportunity to determine whether a further degree of estrogen suppression will be important in producing greater clinical response. With the recent approval of 4-OHA in several countries and the introduction of the potent new compounds, aromatase inhibitors either alone or in combination with the antiestrogen are likely to improve the treatment of breast cancer.     

Oestrogen Receptor in Human Breast Cancer Tissue and Response to Endocrine Therapy

Oestrogen receptor determinations were done in metastatic breast cancer tissue of patients with advanced breast cancer. In 37 patients with progressive disease evaluation of the response to endocrine treatment was possible, following the criteria of the E.O.R.T.C. Co-operative Breast Cancer Group. In 20 patients with receptor-negative tumours two objective remissions were noted; in 17 patients with receptor-positive tumours 14 objective remissions were seen. There seems to be a striking correlation between the presence or absence of oestrogen receptor in tumour tissue and the clinical response to hormonal therapy.