Tamoxifen in combination with cytotoxic chemotherapy in advanced epithelial ovarian cancer. A prospective randomized trial

Immune Modulation of Innate and Adaptive Responses Restores Immune Surveillance and Establishes Antitumor Immunologic Memory

Current immunotherapies have proven effective in strengthening antitumor immune responses, but constant opposing signals from tumor cells and the surrounding microenvironment eventually lead to immune escape. We hypothesized that in situ release of antigens and regulation of both the innate and adaptive arms of the immune system would provide a robust and long-term antitumor effect by creating immunologic memory against tumors. To achieve this, we developed CARG-2020, a genetically modified virus-like vesicle (VLV) that is a self-amplifying RNA with oncolytic capacity and encodes immune regulatory genes. CARG-2020 carries three immune modulators: (i) the pleiotropic antitumor cytokine IL12, in which the subunits (p35 and p40) are tethered together; (ii) the extracellular domain (ECD) of the protumor IL17RA, which serves as a dominant-negative antagonist; and (iii) a shRNA targeting PD-L1. Using a mouse model of ovarian cancer, we demonstrated the oncolytic effect and immune-modulatory capacities of CARG-2020. By enhancing IL12 and blocking IL17 and PD-L1, CARG-2020 successfully reactivated immune surveillance by promoting M1, instead of M2, macrophage differentiation, inhibiting MDSC expansion and establishing a potent CD8+ T cell-mediated antitumoral response. Furthermore, we demonstrated that this therapeutic approach provided tumor-specific and long-term protection against the establishment of new tumors. Our results provide a rationale for the further development of this platform as a therapeutic modality for ovarian cancer patients to enhance antitumor responses and prevent a recurrence.

Immune modulation of innate and adaptive responses restores immune surveillance and establishes anti-tumor immunological memory

Current immunotherapies have proven effective in strengthening anti-tumor immune responses but constant opposing signals from tumor cells and surrounding microenvironment eventually lead to immune escape. We hypothesize that in situ release of antigens and regulation of both the innate and adaptive arms of the immune system will provide a robust and long-term anti-tumor effect by creating immunological memory against the tumor. To achieve this, we developed CARG-2020, a virus-like-vesicle (VLV). It is a genetically modified and self-amplifying RNA with oncolytic capacity and encodes immune regulatory genes. CARG-2020 carries three transgenes: 1 ) the pleiotropic antitumor cytokine IL-12 in which the subunits (p35 and p40) are tethered together; 2) the extracellular domain (ECD) of the pro- tumor IL-17RA, which can serve as a dominant negative antagonist; and 3) shRNA for PD-L1. Using a mouse model of ovarian cancer, we demonstrate the oncolytic effect and immune modulatory capacities of CARG-2020. By enhancing IL-12 and blocking IL-17 and PD-L1, CARG-2020 successfully reactivates immune surveillance by promoting M1 instead of M2 macrophage differentiation, inhibiting MDSC expansion, and establishing a potent CD8+ T cell mediated anti-tumoral response. Furthermore, we demonstrate that this therapeutic approach provides tumor-specific and long-term protection preventing the establishment of new tumors. Our results provide rationale for the further development of this platform as a therapeutic modality for ovarian cancer patients to enhance the anti-tumor response and to prevent recurrence.

Hormone therapy for ovarian cancer: Emphasis on mechanisms and applications (Review)

Ovarian cancer (OC) remains the leading cause of mortality due to gynecological malignancies. Epidemiological studies have demonstrated that steroid hormones released from the hypothalamic-pituitary-ovarian axis can play a role in stimulating or inhibiting OC progression, with gonadotropins, estrogens and androgens promoting OC progression, while gonadotropin-releasing hormone (GnRH) and progesterone may be protective factors in OC. Experimental studies have indicated that hormone receptors are expressed in OC cells and mediate the growth stimulatory or growth inhibitory effects of hormones on these cells. Hormone therapy agents have been evaluated in a number of clinical trials. The majority of these trials were conducted in patients with relapsed or refractory OC with average efficacy and limited side-effects. A better understanding of the mechanisms through which hormones affect cell growth may improve the efficacy of hormone therapy. In the present review article, the role of hormones (GnRH, gonadotropins, androgens, estrogens and progestins) and their receptors in OC tumorigenesis, and hormonal therapy in OC treatment is discussed and summarized.

The roles of pathology in targeted therapy of women with gynecologic cancers

The role of the pathologist in the multidisciplinary management of women with gynecologic cancer has evolved substantially over the past decade. Pathologists' evaluation of parameters such as pathologic stage, histologic subtype, grade and microsatellite instability, and their identification of patients at risk for Lynch syndrome have become essential components of diagnosis, prognostic assessment and determination of optimal treatment of affected women. Despite the use of multimodality treatment and combination cytotoxic chemotherapy, the prognosis of women with advanced-stage gynecologic cancer is often poor. Therefore, expanding the arsenal of available systemic therapies with targeted therapeutic agents is appealing. Anti-angiogenic therapies, immunotherapy and poly ADP ribose polymerase (PARP) inhibitors are now routinely used for the treatment of advanced gynecologic cancer, and many more are under investigation. Pathologists remain important in the clinical management of patients with targeted therapy, by identifying potentially targetable tumors on the basis of their pathologic phenotype, by assessing biomarkers that are predictive of response to targeted therapy (e.g. microsatellite instability, PD1/PDL1 expression), and by monitoring treatment response and resistance. Pathologists are also vital to research efforts exploring novel targeted therapies by identifying homogenous subsets of tumors for more reliable and meaningful analyses, and by confirming expression in tumor tissues of novel targets identified in genomic, epigenetic or other screening studies. In the era of precision gynecologic oncology, the roles of pathologists in the discovery, development and implementation of targeted therapeutic strategies remain as central as they are for traditional (surgery-chemotherapy-radiotherapy) management of women with gynecologic cancers.

A brief review of the management of platinum-resistant-platinum-refractory ovarian cancer

Ovarian cancer, which ranks fifth in cancer deaths among women, is the most lethal gynecologic malignancy. Epithelial ovarian cancer (EOC) is the most common histologic type, with the 5-year survival for all stages estimated at 45.6%. This rate increases to more than 70% in the minority of patients who are diagnosed at an early stage, but declines to 35% in the vast majority of patients diagnosed at advanced stage. Recurrent EOC is incurable. Platinum sensitivity (or lack thereof) is a major determinant of prognosis. The current standard treatment is primary surgery followed by platinum-based chemotherapy. In recurrent platinum-resistant/platinum-refractory EOC, sequential single-agent salvage chemotherapy is superior to multiagent chemotherapy. Multiagent regimens increase toxicity without clear benefit; however, no preferred sequence of single agents is recommended. The impact of targeted therapies and immunotherapies on progression-free survival and overall survival, which remains dismal, is under active investigation. Currently, clinical trials offer the best hope for the development of a new treatment paradigm in this recalcitrant disease.

Activation of estrogen receptor α by estradiol and cisplatin induces platinum-resistance in ovarian cancer cells

Activation of Estrogen receptor (ER) α (α) promotes cell growth and influences the response of cancer cell to chemotherapeutic agents. However, the mechanism by which ERα activation antagonizes cells to chemotherapy-induced cytotoxicity remains unclear. Here, we investigated the effect of cisplatin on ERα activation. In addition, we examined whether down-regulation of ERα modulate cisplatin-mediated cytotoxicity using 2 human ovarian cancer cells (Caov-3 and Ovcar-3) transduced with ERα short hairpin RNA (shRNA). The proliferation assay showed that 17β-estradiol (E2) induced cell proliferation via activation of Akt and extracellular signal-regulated kinase (ERK) cascades, while shRNA mediated downregulation of ERα inhibited the cell proliferation. Immunoblot analysis revealed that cisplatin induced the phosphorylation of ERα at serine 118 via ERK cascade. Luciferase assay showed that cisplatin increases transcriptional activity of estrogen-responsive element (ERE). The E2-stimulated ERα activation attenuated cisplatin-induced cytotoxicity. Meanwhile, down-regulation of ERα inhibited E2-induced protective effect on cisplatin toxicity as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Moreover, Pretreatment with E2 followed by cisplatin decreased the expression of cleaved PARP, and increased the expression of anti-apoptotic protein Bcl-2. Collectively, our findings suggest that activation of ERα by E2 and cisplatin can induce platinum-resistance by increasing the expression of anti-apoptotic protein in ovarian cancer cells. Therefore, our findings provide valuable information that ERα might be a promising therapeutic target for platinum-resistant ovarian cancer.

MAPK Activation Predicts Poor Outcome and the MEK Inhibitor, Selumetinib, Reverses Antiestrogen Resistance in ER-Positive High-Grade Serous Ovarian Cancer

PURPOSE

Although 67% of high-grade serous ovarian cancers (HGSOC) express the estrogen receptor (ER), most fail antiestrogen therapy. Because MAPK activation is frequent in ovarian cancer, we investigated if estrogen regulates MAPK and if MEK inhibition (MEKi) reverses antiestrogen resistance.

EXPERIMENTAL DESIGN

Effects of MEKi (selumetinib), antiestrogen (fulvestrant), or both were assayed in ER-positive HGSOC in vitro and in xenografts. Response biomarkers were investigated by gene expression microarray and reverse phase protein array (RPPA). Genes differentially expressed in two independent primary HGSOC datasets with high versus low pMAPK by RPPA were used to generate a "MAPK-activated gene signature." Gene signature components that were reversed by MEKi were then identified.

RESULTS

High intratumor pMAPK independently predicts decreased survival (HR, 1.7; CI > 95%,1.3-2.2; P = 0.0009) in 408 HGSOC from The Cancer Genome Atlas. A differentially expressed "MAPK-activated" gene subset was also prognostic. "MAPK-activated genes" in HGSOC differ from those in breast cancer. Combined MEK and ER blockade showed greater antitumor effects in xenografts than monotherapy. Gene set enrichment analysis and RPPA showed that dual therapy downregulated DNA replication and cell-cycle drivers, and upregulated lysosomal gene sets. Selumetinib reversed expression of a subset of "MAPK-activated genes" in vitro and/or in xenografts. Three of these genes were prognostic for poor survival (P = 0.000265) and warrant testing as a signature predictive of MEKi response.

CONCLUSIONS

High pMAPK is independently prognostic and may underlie antiestrogen failure. Data support further evaluation of fulvestrant and selumetinib in ER-positive HGSOC. The MAPK-activated HGSOC signature may help identify MEK inhibitor responsive tumors.

Estrogen signaling crosstalk: Implications for endocrine resistance in ovarian cancer

Resistance to anti-estrogen therapies is a prominent challenge in the treatment of ovarian cancer. Tumors develop endocrine resistance by acquiring adaptations that help them rely on alternative oncogenic signaling cascades, which crosstalk with estrogen signaling pathways. An understanding of estrogen signaling crosstalk with these growth promoting cascades is essential in order to maximize efficacy of anti-estrogen treatments in ovarian cancer. Herein, we provide an overview of estrogen signaling in ovarian cancer and discuss the major challenges associated with anti-estrogen therapies. We also review what is currently known about how genomic and non-genomic estrogen signaling pathways crosstalk with several major oncogenic signaling cascades. The insights provided here illustrate existing strategies for targeting endocrine resistant ovarian tumors and may help identify new strategies to improve the treatment of this disease.

Ovarian and breast cancer spheres are similar in transcriptomic features and sensitive to fenretinide

Cancer stem cells (CSCs) are resistant to chemotherapy and are ability to regenerate cancer cell populations, thus attracting much attention in cancer research. In this report, we first demonstrated that sphere cells from ovarian cancer cell line A2780 shared many features of CSCs, such as resistance to cisplatin and able to initiate tumors in an efficient manner. Then, we conducted cDNA microarray analysis on spheres from ovarian A2780 cells, and from breast MCF7 and SUM159 cells, and found that molecular pathways underlying spheres from these cancer cell lines were similar to a large extent, suggesting that similar mechanisms are involved in the genesis of CSCs in both ovarian and breast cancer types. In addition, we showed that spheres from these cancer types were highly sensitive to fenretinide, a stimulus of oxidative stress-mediated apoptosis in cancer cells. Thus, our results not only provide important insights into mechanisms underlying CSCs in ovarian and breast cancer, but also lead to the development of more sophisticated protocols of cancer therapy in near future.

New insights on the role of hormonal therapy in ovarian cancer

Ovarian cancer (OVCA) is the most lethal gynecological malignancy. It is often diagnosed in advanced stages and despite therapy, 70% relapse within 2years with incurable disease. Regimens with clinical benefit and minimal toxicity are urgently needed. More effective hormonal therapies would be appealing in this setting. Estrogens (E2) are implicated in the etiology of OVCA. Estrogens drive proliferation and anti-estrogens inhibit ovarian cancer growth in vitro and in vivo. Despite estrogen receptor (ER) expression in 67% of OVCAs, small anti-estrogen therapy trials have been disappointing and the benefit of hormonal therapy has not been systematically studied in large well-designed trials. OVCAs often manifest de novo anti-estrogen resistance and those that initially respond invariably develop resistance. Estrogens stimulate ovarian cancer progression by transcriptional activation and cross talk between liganded ER and mitogenic pathways, both of which drive cell cycle progression. Estrogen deprivation and estrogen receptor (ER) blockade cause cell cycle arrest in susceptible OVCAs by increasing the cell cycle inhibitor, p27. This review summarizes and discusses scientific and epidemiological evidence supporting estrogen's role in ovarian carcinogenesis, provides an overview of clinical trials of ER blockade and aromatase inhibitors in OVCA and reviews potential causes of antiestrogen resistance. Anti-estrogen resistance was recently shown to be reversed by dual ER and Src signaling blockade. Blocking cross-talk between ER and constitutively activated kinase pathways may improve anti-estrogen therapeutic efficacy in OVCA, as has been demonstrated in other cancers. Novel strategies to improve benefit from anti-estrogens by combining them with targeted therapies are reviewed.

The role of hormonal factors and endocrine therapy in ovarian cancer

The efficacy of the second-line chemotherapy commonly used in both relapsed ovarian cancer patients and those with primary treatment failure remains unsatisfactory. This therapy has a small effect on survival, whereas associated toxicity may diminish the patient's quality of life.

Hormonal factors play a role in ovarian tumorigenesis, and inhibition of the stimulating effects of estrogens may exert a clinical benefit. The role of hormonal therapy as a palliative therapeutic alternative for ovarian cancer remains undetermined. This modality may result in long-term stabilization of disease in individual patients and less frequently in tumor remission.

In this article the role of hormonal factors and recent literature of various forms of hormonal therapy for ovarian cancer are presented.

Molecular clustering based on ERα and EIG121 predicts survival in high-grade serous carcinoma of the ovary/peritoneum

Assessment of estrogen receptor (ER) expression by immunohistochemistry has yielded inconsistent results as a prognostic indicator in ovarian carcinoma. In breast and endometrial carcinomas, panels of estrogen-induced genes have shown improved prognostic capability over the use of ER immunohistochemistry alone. For both breast and endometrial cancers, overexpression of estrogen-induced genes is associated with better prognosis. We hypothesized that analysis of a panel of estrogen-induced genes can predict the outcome in ovarian carcinoma and potentially differentiate between tumors of varying hormonal responsiveness. From a cohort of 219 women undergoing ovarian cancer surgery from 2004 to 2007, 83 patients were selected for inclusion. All patients had advanced stage ovarian/primary peritoneal high-grade serous carcinoma and underwent primary surgical debulking, followed by adjuvant treatment with platinum and taxane agents. The expression of ERα and six genes known to be induced by estrogen in the female reproductive tract (namely EIG121, sFRP1, sFRP4, RALDH2, PR, and IGF-1) was measured using quantitative RT-PCR. Unsupervised cluster analyses were used to categorize patients as high or low gene expressors. Gene expression results were then compared with those for ER immunohistochemistry. Clusters were compared using χ(2) analyses, and Cox proportional hazards models were used to evaluate survival outcomes. The median follow-up time was 38.7 months (range: 1-68). A cluster defined by EIG121 and ERα segregated tumors into distinct groups of high and low gene expressors. Shorter overall survival (OS) was associated with high gene expression (HR 2.84 (1.11-7.30), P=0.03), even after adjustment for other covariates. No difference in ER immunohistochemistry expression was noted between gene clusters. In contrast to other hormonally driven cancers, high expression of ERα and the estrogen-induced gene EIG121 predicts shorter OS in patients with high-grade serous ovarian carcinoma. Such a biomarker panel may potentially be used to guide management with estrogen antagonists in this patient population.

Tamoxifen for relapse of ovarian cancer

BACKGROUND

Tamoxifen is an important drug for treating breast cancer. Ovarian cancer cells are known to possess receptors for hormones and may thus also respond to tamoxifen.

OBJECTIVES

Tamoxifen is used to treat breast cancer in women whose tumours have oestrogen receptors. Since ovarian cancers also commonly have oestrogen receptors, it has been suggested that tamoxifen may be of some benefit. The objective of this review was to assess the effects of tamoxifen in women with relapsed ovarian cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Issue 1, 2009. Cochrane Gynaecological Cancer Group Trials Register, MEDLINE from 2002 to April 2009, EMBASE from 2002 to April 2009. We also searched registers of clinical trials, abstracts of scientific meetings, reference lists of review articles and contacted experts in the field, as well as drugs companies.

SELECTION CRITERIA

Randomised and non-randomised studies of tamoxifen in women with ovarian cancer who have not responded to conventional chemotherapy. Only trials involving 10 or more patients were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed whether potentially relevant studies met the inclusion criteria. No trials were found and therefore no data were analysed.

MAIN RESULTS

The search strategy identified 1392 unique references of which 1360 were excluded on the basis of title and abstract. The remaining 32 articles were retrieved in full, but none satisfied the inclusion criteria. Only observational data from single arm studies of women treated with tamoxifen were reported.

AUTHORS' CONCLUSIONS

We are unable to make any evidence-based recommendations as we found no comparative studies assessing the effectiveness of tamoxifen in women with recurrent ovarian cancer. There is limited evidence on anti-tumour activity from phase 2 studies, but these contain no data on the effect of tamoxifen on symptom control, QOL or the prolongation of life.

Antiestrogen therapy in recurrent ovarian cancer resulting in 28 months of stable disease: a case report and review of the literature

Hormonal therapy for adjuvant treatment of ovarian cancer may provide a low toxicity option in some patients with refractory disease. A 53 year-old patient with stage IIIC papillary serous ovarian cancer previously treated with multiple chemotherapy regimens with platinum-resistant disease was treated with antiestrogen therapy for 28 months before requiring reinstitution of cytotoxic chemotherapy. Hormonal therapy may be effective in a subset of epithelial ovarian cancer patients with endocrine sensitivity and should be considered in the treatment of platinum-resistant patients.

Estradiol attenuates EGF-induced rapid uPAR mobilization and cell migration via the G-protein-coupled receptor 30 in ovarian cancer cells

Epidermal growth factor (EGF) stimulates proliferation and migration in ovarian cancer cells, and high tumor expression of the EGF system correlates with poor prognosis. Epidermal growth factor upregulates urokinase plasminogen activator receptor (uPAR) on the cell surface via 3 distinct mechanisms: rapid mobilization of uPAR from detergent-resistant domains, increased mRNA, and decreased degradation. G-protein-coupled receptor 30 (GPR30) is a newly identified membrane estrogen receptor (ER).The objective of this study was to explore the effects of 17beta-estradiol (E(2)) on uPAR expression and cell migration in ovarian cancer cells and further to identify the ER involved.We used 7 ovarian cancer cell lines, cell migration assay, cellular binding of (125)I-uPA, cellular degradation of (125)I-uPA/PAI-1 complex, enzyme-linked immunosorbent assay for uPAR, solid-phase enzyme immunoassay for ERalpha, and quantitative polymerase chain reaction. Estradiol attenuates the stimulatory effect of EGF on cell migration and uPAR expression. Specifically, E(2) reduces the very rapid increase of detergent extractable uPAR, which occurs within minutes of EGF stimulation and probably represents mobilization of uPAR from detergent-resistant domains such as lipid rafts. Estradiol influenced neither the amount of uPAR mRNA nor the rate of uPAR degradation or solubilization. The nuclear ER antagonists ICI 182780 and tamoxifen, which are GPR30 agonists, as well as the specifically constructed GPR30 agonist G1, mimicked the effect of E(2) on uPAR expression and cell migration. OVCAR-3 cells express mRNA for GPR30.Estradiol attenuates EGF-induced mobilization of ligated uPAR from detergent-resistant domains and subsequent migration in ovarian cancer cells. The response to various ER ligands indicates that this effect is mediated via the membrane ER GPR30.

Prognostic value of hormonal receptors, p53, ki67 and HER2/neu expression in epithelial ovarian carcinoma

OBJECTIVE

The role of molecular and biological factors in ovarian cancer is controversial. We investigated the levels of the estrogen (ER) and progesterone (PR) receptors, HER2/neu, p-53 and Ki 67 in patients with advanced ovarian cancer and correlated the results with the clinical course in order to define their predictive or prognostic significance.

METHODS

Paraffin-embedded tumor tissues from 72 patients with ovarian cancer treated from 1999 to 2003 were analyzed. Overexpression of C-erb-B2 was defined as herceptest ++/+++ and positive fluorescence in situ hybridization (FISH) or herceptest +++/+++. Positivity for ER and PR was determined by > or =10% of the cellular membranes immunostained. Statistical analysis was performed to evaluate the prognostic impact of the molecular markers.

RESULTS

49 of the 72 patients were ER + (68%) and 36 PR + (50%). In 45 patients (62.5%) expression of p53 was > or =10%. Overexpression of C-erb-2 was found in 4 tumor samples (5%). A Ki67 labelled nuclear area >30% was found to be associated with a higher rate of complete response (chi(2); p=0.05). None of the biological markers were significantly associated with progression free survival (PFS). By multivariate analysis residual tumor after debulking surgery and ER status were associated with OS (p< or =0.05).

CONCLUSIONS

Ki67 nuclear expression >30% is predictive of complete response in advanced ovarian cancer. HER2/neu overexpression is scarce in our study. Positive ER is an independent prognostic factor for OS. Further research with larger studies and hormonal treatment is guaranteed.

Pharmaceutical management of ovarian cancer : current status

Over recent decades, truly impressive progress has been made in the outcome associated with the pharmacological antineoplastic management of women with advanced ovarian cancer. Following initial surgery, the large majority of patients with this malignancy will receive a chemotherapy regimen that includes a platinum drug (carboplatin or cisplatin) and a taxane (paclitaxel or docetaxel). Currently, objective responses are observed in approximately 60-80% of patients treated in the front-line setting, with documented improvements in overall survival compared with prior non-platinum and taxane programmes. Unfortunately, despite the high response rate to initial chemotherapy, the majority of women with advanced disease will experience recurrence of the malignant process and be candidates for a variety of possible second-line therapeutic options. It is well recognized that ovarian cancer patients who are documented to experience an initial response to platinum-based chemotherapy but where the disease recurs approximately 6 or more months following the completion of primary therapy, may have another clinically meaningful response (both objective and subjective) to a second platinum-based strategy. However, an optimal management approach in this setting remains to be defined. Furthermore, the malignant cell populations in all ovarian cancer patients who experience an initial relapse of the disease process will eventually be resistant to the platinum agents. In this setting, multiple drugs have been shown to be biologically active. Again, an optimal strategy to be employed in the platinum-resistant setting has yet to be demonstrated through the conduct of evidence-based trials. Reasonable goals of therapy in women with recurrent or resistant ovarian cancer are to improve overall survival, reduce the severity (and delay the occurrence) of symptoms and optimize overall quality of life.

Hormonal therapy in ovarian cancer

Ovarian carcinoma continues to be the leading cause of death due to gynecological malignancy. Epidemiologic studies indicate that steroid hormones play roles in ovarian carcinogenesis. Gonadotropins, estrogen, and androgen may be causative factors, while gonadotropin-releasing hormone and progesterone may be protective factors in ovarian cancer pathogenesis. Experimental studies have shown that hormonal receptors are expressed in ovarian cancer cells and mediate the growth-stimulatory or growth-inhibitory effects of the hormones on these cells. Hormonal therapeutic agents have been evaluated in several clinical trials. Most of these trials were conducted in patients with recurrent or refractory ovarian cancer, with modest efficacy and few side effects. Better understanding of the mechanisms through which hormones affect cell growth may improve the efficacy of hormonal therapy. Molecular markers that can reliably predict major clinical outcomes should be investigated further in well-designed trials.

Hormonal therapy for epithelial ovarian cancer

Despite the fact that hormonal therapy has been employed in the management of ovarian cancer for more than 40 years, there is limited information available in the peer-reviewed medical literature to document the beneficial impact of the strategy, either on improvement in cancer-related symptoms or prolongation of survival. Existing data suggest that approximately 5-10% of ovarian cancer patients treated with a hormone-based strategy in the second-line setting will achieve evidence of substantial tumor shrinkage, with a larger proportion of individuals likely to demonstrate stabilization of the disease process for a highly variable time interval. The major advantage with the use of hormonal treatments is the well-recognized and highly favorable toxicity profile associated with this class of antineoplastic agents.

Metastasis to sigmoid colon mucosa and submucosa from serous borderline ovarian tumor: response to hormone therapy

Distant metastasis to sites other than lymph nodes of borderline ovarian tumor is rare. We describe a case metastasized to sigmoid colon mucosa and submucosa. The metastatic lesion was detected incidentally by screening colonoscopy 7 years after the patient was treated for the primary tumor. The metastatic lesion responded well to treatment with oral Arimidex 1 mg/day. A follow-up colonoscopy with biopsy and imaging studies after 3 months of treatment revealed no evidence of disease in the sigmoid colon. This case showed that the sigmoid colon mucosa and submucosa should be considered as one of distant metastatic sites of a serous borderline ovarian tumor and the favorable response to Arimidex provides support the use of hormone therapy in women with serous borderline ovarian tumor.

Is there still a role for hormonal therapy?

Ovarian cancer arises from the specialized surface epithelium, which routinely expresses receptors for reproductive hormones and growth factors. However, as a group, ovarian tumors are less responsive to hormonal therapy than either breast or endometrial cancer. The complex factors that govern hormonal response and associated molecular interactions are under intensive investigation, with the generation of new hypotheses that merit clinical evaluation. As such, it is reasonable to consider a number of potential hormonal interventions related to the prevention and treatment of ovarian cancer.

Role of CT and MR imaging in predicting optimal cytoreduction of newly diagnosed primary epithelial ovarian cancer

OBJECTIVE

To determine the relative accuracy of CT or MR imaging in the detection of inoperable tumor sites prior to cytoreductive surgery in a large series of patients with newly diagnosed primary epithelial ovarian cancer.

METHODS

One hundred thirty-seven women with newly diagnosed primary epithelial ovarian cancer underwent CT (n = 91) or MR imaging (n = 46) prior to cytoreductive surgery. The following imaging criteria were used to identify inoperable tumor sites: (1) peritoneal implants greater than 2 cm in maximum diameter in the porta hepatis, intersegmental fissure, gall bladder fossa, subphrenic space, gastrohepatic ligament, gastrosplenic ligament, lesser sac, or root of the small bowel mesentery; (2) retroperitoneal adenopathy greater than 2 cm in maximum diameter above the renal hila; (3) hepatic metastases or abdominal wall invasion. Imaging results were compared with operability at surgery.

RESULTS

Cytoreductive surgery was suboptimal in 21 of the 137 (15%) patients. Sixteen of these patients had inoperable tumor on preoperative imaging, while one additional patient had apparently inoperable tumor on imaging but was optimally debulked at surgery. The sensitivity, specificity, positive predictive value, and negative predictive value of preoperative imaging for the prediction of suboptimal debulking were 76% (16/21), 99% (115/116), 94% (16/17), and 96% (115/120), respectively. CT and MR imaging were equally effective (P = 1.0) in the detection of inoperable tumor.

CONCLUSION

Preoperative CT and MR imaging are equally accurate in the detection of inoperable tumor and the prediction of suboptimal debulking in newly diagnosed epithelial ovarian cancer. This suggests imaging may help select patients who might be more appropriately managed by neoadjuvant chemotherapy.

Neoadjuvant chemotherapy for the management of ovarian cancer

Neoadjuvant chemotherapy refers to the administration of chemotherapy before definitive surgery is performed; this approach was introduced into the management of ovarian cancer approximately one decade ago, initially for use in women who were medically unable to tolerate aggressive cytoreductive surgery. Subsequently, neoadjuvant chemotherapy was employed in women who, by diagnostic imaging analysis, were unlikely to undergo successful optimal cytoreductive surgery. Only very limited data are available on the use of neoadjuvant chemotherapy in the management of women with apparent advanced ovarian cancer; these data are derived mainly from single institution experiences and suggest that this approach may increase disease-free survival but does not improve overall survival for the patient. However, it has consistently enhanced the feasibility of optimum surgical cytoreduction once neoadjuvant chemotherapy has been administered. Reduced blood loss, and shorter operations, intensive care unit stays and overall hospitalizations have been well documented. The methods for selecting candidates for neoadjuvant chemotherapy vary among institutions. Non-optimal surgical cytoreducibility has been assessed on the basis of diagnostic imaging studies, laparoscopic assessment and/or laparotomies. Currently, neoadjuvant chemotherapy is most beneficial for women who are medically impaired and unable to tolerate aggressive cytoreductive surgery and for women who are found to have such aggressive cancers that optimal cytoreductive surgery does not appear by diagnostic imaging or direct visualization to be possible.

Tamoxifen therapy for ovarian cancer in the adjuvant and advanced settings: systematic review of the literature and implications for future research

BACKGROUND

Ovarian neoplasms frequently express hormonal receptors and are sensitive to hormonal manipulations, as shown by preclinical and clinical studies. However, despite the outstanding relevance of hormonal adjuvant therapy in breast cancer and the importance of receptor status as a predictive factor, few trials have addressed these issues in ovarian cancer.

METHODS

Computerized and manual searches were performed to identify preclinical and clinical studies evaluating single-agent tamoxifen activity in ovarian cancer or any kind of hormonal therapy employed as adjuvant therapy for ovarian cancer.

RESULTS

In advanced tumors, none of the trials was performed exclusively in chemonaive patients, but those including less heavily pretreated patients showed greater response rates. Some studies found a correlation between receptor status and activity (although differences were not significant), whereas other trials did not. Nevertheless, none were specifically designed to answer this question. Few randomized trials comparing hormonal treatment and chemotherapy versus chemotherapy alone were identified. Although their results were negative, all were small, and none was designed with the rigor that allowed adjuvant hormonal therapy to become successfully established in breast cancer.

CONCLUSION

The activity of tamoxifen in advanced ovarian cancer has not been adequately evaluated and its role may have been underestimated. Furthermore, the relevance of adjuvant hormonal therapy in ovarian cancer and the predictive value of hormonal receptors have never been studied in well-designed trials. Additional studies to clarify the role of tamoxifen for this indication are warranted.

A combination of platinum and tamoxifen in advanced ovarian cancer failing platinum-based chemotherapy: results of a Phase II study

The treatment of recurrent or progressive ovarian cancer has limited therapeutic potential. The clinical outcome of second-line therapy largely depends on the potential chemo-sensitivity of the tumor expressed during up-front chemotherapy, as well as on the treatment-free interval from the last course of cytotoxic therapy. However, the identification of agents such as tamoxifen (TAM) at nontoxic doses, able to act synergistically with standard chemotherapy, may be useful to overcome resistance. Fifty patients with recurrent or progressive ovarian cancer following platinum (P)-based chemotherapy (28 platinum-resistant and 22 platinum-sensitive) entered a Phase II trial to evaluate the efficacy and toxicity of P re-challenge with the addition of TAM as a chemotherapy response modulator. The choice of the P compound (100 mg/m2 cisplatin or 400 mg/m2 carboplatin, q3 weeks) was made on the basis of the prior total cisplatin dose and the presence of neurotoxicity. TAM was administered at the doses of 80 mg/day for 30 days followed by 40 mg/day for the remaining period of treatment. Toxicity consisted mainly of mild to moderate nausea and vomiting (76%), peripheral neuropathy (43%), nephrotoxicity (4%), anemia (16%), leukopenia (58%) and thrombocytopenia (16%). The overall response to the P-TAM combination was 50% (complete response 30%; partial response 20%) with a median duration of 8.5 months (3-42). Sixty-four percent of the P-sensitive and 39% of the P-resistant patients responded (59% and 33%, respectively, for those bearing measurable disease). The overall median survival was 23 (3-48) and 19 months for the patients with measurable disease (20 months for the P-resistant group). This phase II trial confirmed the activity for a re-challenge employing a P compound and TAM in clinically defined P-resistant ovarian cancer patients. The mild toxicity profile and the relatively low cost of the treatment render further investigations on the P-TAM regimen worthwhile.

Tamoxifen for relapse of ovarian cancer

BACKGROUND

Tamoxifen is an important drug for treating breast cancer. Ovarian cancer cells are known to possess receptors for hormones and may thus also respond to tamoxifen.

OBJECTIVES

Tamoxifen is used to treat breast cancer in women whose tumours have oestrogen receptors. Since ovarian cancers also commonly have oestrogen receptors, it has been suggested that tamoxifen may be of some benefit. The objective of this review was to assess the effects of tamoxifen in women with relapsed ovarian cancer.

SEARCH STRATEGY

We searched the Cochrane Gynaecological Cancer Group trials register and references from relevant articles. We also contacted researchers and drug companies.

SELECTION CRITERIA

Randomised and non-randomised studies of tamoxifen in women with ovarian cancer who have not responded to conventional chemotherapy. Only trials involving 10 or more patients were included.

DATA COLLECTION AND ANALYSIS

One reviewer assessed eligibility and extracted data from non-randomised studies. Two reviewers were to have independently assessed the quality and extracted data from any randomised trials found.

MAIN RESULTS

Eleven non-randomised series, one non-randomised phase two study and two randomised trials were included. Only observational data from women treated with tamoxifen are reported. Sixty of 623 women (9.6%) treated with tamoxifen achieved an objective response to treatment. However this varied from 0% to 56% in different studies. Stable disease, for variable periods of four weeks or more, was observed in 131 of 411 (31.9%) women from eight studies. There were not enough data to assess duration of response, survival, or the palliative effect of tamoxifen on symptom control or quality of life.

REVIEWER'S CONCLUSIONS

There is some evidence from observational studies that tamoxifen may produce a response in a modest proportion of women with relapsed ovarian cancer. However, there are no reliable data from randomised controlled trials.

The oestrogen receptor (ER) in vulva, vagina and ovary

The oestrogen receptor (ER) has been identified in normal and neoplastic epithelia of the vulva, vagina and ovary using biochemical, immunohistochemical (IHC) and molecular techniques. Its presence has not translated into effective antineoplastic therapy for malignancies arising from these sites.

Primary and salvage therapy with LH-RH analogues in ovarian cancer

The efficacy of modern surgical and chemotherapeutic options for the treatment of ovarian cancer is still unsatisfactory. In spite of the availability of new cytotoxic agents, the majority of ovarian cancer patients will finally die of chemoresistant disease. LH-RH agonists in conventional doses have been shown to induce objective responses in approximately 9% of patients with refractory ovarian cancer and disease stabilization in 26% of these women. As toxicity of LH-RH agonists is low or absent, and since their efficacy is not strikingly inferior to that of experimental chemotherapy, they have a vital indication in the salvage situation. A trial is presently being performed among platinum/taxol-refractory patients, comparing the impact of the LH-RH agonist leuprorelin and that of the cytotoxic agent treosulfane on survival and quality of life. The addition of LH-RH agonists in conventional doses to standard first-line surgical and chemotherapy does not improve relapse-free and overall survival. For many years it has been suggested that LH-RH agonists inhibit proliferation of ovarian cancer by suppressing endogenous gonadotropins, which were considered to be mitogenic in this malignancy. Recent experimental and clinical data have made this hypothesis questionable. In contrast, a large body of experimental evidence has emerged during the past few years indicating that LH-RH agonists and antagonists directly inhibit proliferation of ovarian cancer through LH-RH receptors expressed by 80% of these tumors. To exploit these direct antiproliferative effects of LH-RH analogues, higher tissue concentrations are necessary than those achieved with the conventional doses used today. Alternative routes of administration or higher systemic doses of potent LH-RH antagonists, such as Cetrorelix, might improve the efficacy of this approach. Clinical trials addressing this issue are under way. Finally, the LH-RH receptors expressed by ovarian cancers could be employed for targeted chemotherapy using cytotoxic LH-RH analogues. This approach has been shown to be effective in experimental models and might be tested in clinical trials in the near future.

Progesterone receptor status is a significant prognostic variable of progression-free survival in advanced epithelial ovarian cancer

The purpose of this study was to determine if tumor estrogen receptor (ER) or progesterone receptor (PR) status were significant prognostic variables of survival and progression-free survival among patients with International Federation of Gynecology and Obstetrics (FIGO) stage III and IV epithelial ovarian cancer. Tumor steroid receptor status was evaluated among 67 consecutive patients who underwent primary surgery from June 1983 through September 1990. Characteristics of receptor-negative and receptor-positive populations were compared by chi-square analysis. Univariate and multivariate analyses were used to identify variables prognostic of survival and progression-free survival. Fifty-one of 67 patients (76.1%) had ER-positive tumors and 31 (46.3%) patients had PR-positive tumors. Significant differences between receptor-positive and receptor-negative populations were not observed. Neither univariate nor multivariate analysis identified ER or PR status as significant prognostic variables of survival (p = 0.93 and p = 0.06, respectively). Progesterone receptor-positive status was a significant prognostic variable of progression-free survival in both univariate (p = 0.03) and multivariate (p = 0.04) analyses even after adjustment for residual disease and patient age. Estrogen receptor status was not a significant prognostic indicator of progression-free survival in either univariate or multivariate analyses. Progesterone receptor-positive tumor status is shown to be an independent prognostic variable of improved progression-free survival among patients with advanced epithelial ovarian cancer.

Tamoxifen synergizes the antiproliferative effect of cisplatin in human ovarian cancer cells: enhancement of DNA platination as a possible mechanism

We investigated the chemosensitizing activity of tamoxifen (TAM) on estrogen receptor negative ovarian cancer cell lines sensitive (A2780 WT) and resistant to cisplatin (CP) (A2780 CP3). Our results showed that the treatment of both cell lines with the association TAM + CP (concentration range 0.01-1 microN and 0.1-1 microgram/ml, respectively) results in a synergistic antiproliferative activity and a complete reversal of the acquired CP-resistant phenotype. We demonstrated that in A2780 cells the addition of TAM to CP treatment is able to significantly enhance at every tested CP dose (P < 0.001) the amount of platinum (Pt) bound to the DNA. Since Pt-DNA levels in the genome are clearly related to the growth inhibitory effect of CP (correlation value = 0.97, P < 0.001) in our experimental model, we hypothesized that TAM could act synergistically with CP and overcome the acquired CP-resistance by enhancing Pt binding to the DNA. We suggest that, from a clinical point of view, TAM may be usefully included in CP-based chemotherapy regimens for ovarian cancer patients since plasma concentrations of the drug capable of in vitro CP resistance modulation are achievable in vivo. A prospective clinical trial to verify the clinical usefulness of combined TAM + CP treatment in ovarian cancer patients refractory to prior Pt-based chemotherapy is now underway in our department.

Clinical trials in patients with epithelial ovarian cancer: past, present and future

Combinations of surgery and chemotherapy are crucial in the treatment of ovarian cancer. This article reviews the conclusions of all recently performed trials and gives information on the now open randomized studies. The importance of radical surgery in combination with chemotherapy in early disease is clear, but uncertainties still exist in relation to timing and choice of chemotherapy. Many data from trials are helpful in outlining the indications for cytoreductive surgery, the timing of this procedure, second-look laparotomy in clinically complete remission, and secondary cytoreduction, but many details are yet to be addressed in future randomized studies. The place of new chemotherapeutic agents (in advanced disease and in adjuvant setting) is currently being investigated in many clinical trials.

Luteinizing hormone-releasing hormone agonist triptorelin in combination with cytotoxic chemotherapy in patients with advanced ovarian carcinoma. A prospective double blind randomized trial. Decapeptyl Ovarian Cancer Study Group

BACKGROUND

Several lines of evidence suggest that the proliferation of ovarian carcinoma might be stimulated by gonadotrophins. A number of Phase I/Phase II clinical trials have reported that the suppression of endogenous luteinizing hormone and follicle-stimulating hormone secretion by luteinizing hormone-releasing hormone (LHRH) analogs induced objective remissions and/or disease stabilization in 10-30% of patients with advanced refractory ovarian carcinoma. The current study was performed to evaluate whether the addition of LHRH agonist treatment to standard platinum-based chemotherapy could prolong survival of patients with surgically treated Stage III or IV epithelial ovarian carcinoma.

METHODS

One hundred and thirty-five patients with Stage III or IV epithelial ovarian carcinoma participated in this prospective randomized double blind trial. After cytoreductive surgery, 69 patients received monthly injections of a depot preparation of the LHRH agonist [D-Trp6] LHRH (triptorelin, 3.75 mg) and 66 patients received placebo until their deaths or termination of trial, respectively. All patients were treated with a standard platinum-based chemotherapy, and, if necessary, with second- or third-line cytotoxic regimens.

RESULTS

Endogenous gonadotrophins were reliably suppressed in patients treated with triptorelin. However, their progression free and overall survival were not significantly different from that of patients receiving placebo injections (statistical power > 80% for a difference between both groups of > or = 20%).

CONCLUSIONS

The results of this trial suggest that the suppression of endogenous gonadotrophins by conventional doses of an LHRH agonist produces no relevant beneficial effects in patients with advanced ovarian carcinoma who receive standard surgical cytoreduction and cytotoxic chemotherapy.

A trend toward more conservative surgery in gynecologic oncology

A trend toward more conservative surgical intervention is evident in the current management of many gynecologic malignancies. The trend to manage vulvar carcinoma has moved away from the standard en bloc radical vulvectomy and bilateral lymphadenectomy and now consists of more limited excision of the primary tumor as well as of the regional lymph nodes. In preinvasive cervical carcinoma, conization is preferred instead of hysterectomy. The possibility for a more conservative surgical approach is also being explored for the treatment of selected early stage and advanced or recurrent cervical carcinomas. Although the primary surgical treatment of endometrial carcinoma remains unchanged, the necessity to perform (in all cases) the more extensive procedure required for staging purposes is being challenged. In early stage borderline ovarian tumors, not only adnexectomy but cystectomy alone is considered acceptable and reexploration for staging purposes may be unwarranted. In stage IA invasive carcinoma, adnexectomy of the involved side only is probably also sufficient. In advanced ovarian carcinoma, the more aggressive cytoreduction involving multiple organ resection is being restrained. Secondary debulking is performed only on a selective basis and the routine performance of second-look laparotomy has been given up.

Frontiers of Ovarian Cancer Therapy

Since the majority of patients with ovarian cancer present with advanced stages of disease, more effective systemic approaches are needed to add to the benefits of surgical staging and debulking. New combinations of taxoids with cisplatin have prolonged survival, and other chemotherapeutic agents are being evaluated. Immunotherapy, including intraperitoneal approaches with monoclonal antibodies, cellular therapies and vaccines, hormone therapy with well-known drugs such as tamoxifen, and gene therapy give promise for the future.

Epidermal growth factor, oestrogen and progesterone receptor expression in primary ovarian cancer: correlation with clinical outcome and response to chemotherapy

The expression of epidermal growth factor receptor (EGFR), oestrogen receptor (ER) and progesterone receptor (PR) was assayed by a radioreceptor method in 117 primary ovarian cancers. EGFR was not significantly related to any of the clinicopathological parameters examined. In patients with stage II-IV disease who underwent second-look surgery after primary chemotherapy, a significant correlation between high EGFR levels and poor response to chemotherapy was demonstrated (P = 0.031). Moreover, post-operative residual tumour showed an independent role in predicting chemotherapy response (P = 0.0007) and EGFR status showed a borderline significance (P = 0.052) in the multivariate analysis. No correlation between steroid hormone receptors and clinicopathological parameters was observed. Whereas a significant relationship was shown between EGFR positivity and a shorter overall survival (OS) (P = 0.0022) and progression-free survival (PFS) (P = 0.0033), patient survival was not related to steroid hormone receptor status. Among the parameters tested only stage, ascites and EGFR status retained an independent prognostic value in the multivariate analysis.

Tamoxifen modulation of cisplatin cytotoxicity in human malignancies

Recent clinical trials have indicated that addition of tamoxifen (TAM) to a combination of cisplatin (DDP), carmustine and dacarbazine markedly increases the overall objective response rate of patients with metastatic malignant melanoma. Previous studies have determined that there is remarkable synergy between TAM and DDP in a human melanoma cell line T-289. Using the technique of median effect analysis, in clonogenic assay, we observed a highly synergistic interaction between TAM and DDP. To determine whether or not this synergistic interaction was unique to human melanomas, or is generally observed in other types of malignancy, we examined the nature of this interaction using a human ovarian carcinoma and small cell lung cancer cell line. Synergy was observed in both cell lines. In the case of all 3 types of malignancy, synergy was observed at concentrations of both TAM and DDP that can be achieved in patients. Our results demonstrate that cytotoxic synergy between the DDP and TAM is observed in cell lines established from multiple types of human malignancies. It is important to note that the synergy between TAM and DDP is not dependent on the presence of estrogen or progesterone receptors. Since TAM is well tolerated by patients, it is particularly attractive as a potential agent with which to sensitize human tumors to DDP.

Dose intensity analysis in advanced ovarian cancer patients

To determine if chemotherapy dose intensity influences treatment outcome in advanced ovarian cancer, all randomised studies of first line chemotherapy, published between 1975 and 1989, were analysed for relationships between planned dose intensity and (a) objective response and (b) median survival. Total dose intensity of each study regimen was calculated and a weighted regression model providing for systemic differences in response or survival among studies was utilised. Hence, treatment arms of different studies were never directly compared. In addition, relative dose intensities of individual drugs within combinations was similarly evaluated. The improvement in objective response rate when adding one unit of total dose intensity ranged between 12% and 16% depending on baseline response rate. The improvement in median survival when adding one unit of total dose intensity ranged between 2 and 4 months. One unit of total dose intensity corresponds to, for example, 20 mg m2 week of cisplatin, or 25 mg m2 week of doxorubicin, or 350 mg m2 week of cyclophosphamide. The analysis of individual drugs suggested that doxorubicin and the platinum compounds were about equally effective, with cyclophosphamide being less effective. The methodological benefits and limitations of the approach used and the implication of the results are discussed.

NEU protein overexpression in benign, borderline, and malignant ovarian neoplasms

In situ hybridization (ISH) analysis of 24 benign, borderline, and malignant ovarian tumor specimens revealed NEU transcript expression by epithelial elements in approximately two-thirds of the samples and high-level expression in 3 grade 3 adenocarcinomas. Immunohistochemical staining (IHC) of a total of 86 specimens (including 17 of those studied by ISH) localized NEU antigen expression to epithelial cells in 36 of 86 samples with strong membrane staining observed in 12, including 1 benign, 1 borderline serous carcinoma, 3 clear cell/endometrioid carcinomas, and 7 predominantly papillary serous carcinomas with areas of clear cell/endometrioid histology. Clinical correlation of the IHC results for the 72 Stage I-IV invasively malignant neoplasms revealed no statistically significant association of the intensity of NEU IHC staining with either relapse-free or overall survival. However, more of the patients whose tumors showed strong membrane staining for NEU antigen suffered relapses of disease by 3 and 4 years than did patients whose tumors showed weak or no membrane staining. These results suggest a role for the NEU gene product in the physiology of benign ovarian surface epithelium and the neoplastic epithelium of preinvasive borderline and some invasively malignant adenocarcinomas.

Intracellular actions of steroid hormones and their therapeutic value, including the potential of radiohalosteroids against ovarian cancer

The biological activities of steroid hormones are effected via intracellular receptors. The receptors are part of a ligand-activated family of transcription regulator proteins that are critical for steroid-regulated cell differentiation. With recombinant cDNA technology, yeast and cultured animal cells can be made to express mammalian cDNA steroid receptors from cDNA clones that contain deletions and substitutions. Among the leading problems addressed in these models is the characterization of sequences that promote association or interaction with other transcription regulating molecules, including oncogene products. Recently it has been found that heat shock proteins may serve not only to stabilize the receptor proteins but also to precondition the activation imparted by ligand binding. Aberrant receptor proteins can be found in ovarian cancer. Whether aberrant receptor proteins are associated with transformation in general or with a variable clinical response to steroidal or anti-steroidal therapy is not known. Even after chemotherapy, steroid receptors are expressed in the metastases of ovarian cancers seen clinically, and they may have potential uses for localization and treatment of receptor-rich cancers. Radioligand pharmaceuticals appropriate for imaging or for site-directed radiocytotoxicity can be sequestered to the nuclei of receptor-rich cancers. Initial clinical imaging and therapy trials with such pharmaceuticals have been approved and begun. In the use of halogenated estrogen radiopharmaceuticals, liver metabolism and enterohepatic recirculation are important considerations. Ascites prolongs retention of a radiohalogenated estrogen in the abdominal cavity. Distant metastases have been localized with [123I]-estrogen in breast cancer patients in pre-operative procedures. Receptor-mediated cytotoxicity occurs when estrogen receptor radioligand pharmaceuticals that are Auger electron emitters are used in vitro.

Synergistic antiproliferative activity of tamoxifen and cisplatin on primary ovarian tumours

We looked for the presence of the so-called type II oestrogen binding sites (EBS), in four oestrogen (ER) and progesterone (PR) receptor negative primary ovarian tumours. Moreover, the colony-forming assay was used to evaluate the response of ovarian cancer cells from these primary tumours to tamoxifen and cisplatin used alone or in combination. All tumours contained type II EBS, and tamoxifen was able to compete for [3H] oestradiol binding to these sites. Cisplatin and tamoxifen exhibited a dose-dependent inhibition of colony formation in a range of concentrations between 10 and 1000 micrograms/l and 37 and 3710 micrograms/l, respectively. The combination of the two drugs resulted in a synergistic antiproliferative activity, with a potentiation up to and beyond 50-fold. Our results show that in ovarian cancer tamoxifen interacts with type II EBS with an affinity consistent with the concentration effective both in inhibition of colony formation and in synergising cisplatin activity. Based on the experiments performed the action of tamoxifen on cell growth is independent of ER expression, and could be mediated by type II EBS. The possibility that the association of tamoxifen and cisplatin may result in an improved clinical response in ovarian cancer should be investigated.

Biodistribution, with high uptake by the reproductive tract, of an intraperitoneally infused radiohalogenated steroidal estrogen-receptor ligand

We infused [123I]16 alpha-(123I)-iodo-estradiol ([123I]E2) intraperitoneally (i.p.) into swine to study its biodistribution and to explore the i.p. use of radiohalogenated steroid estrogen-receptor (ER) ligands as a potential option for diagnosing and treating intra-abdominal, retroperitoneal, and distant sites of advanced ER-rich malignancies. Fifty to 80% of the radiolabel was absorbed from the peritoneal cavity within 30 minutes, and 30 to 50% of the infused radiolabel was excreted in the urine within 2 hr. The rate of biliary clearance was maximal within 25 minutes. At 3 hr, the ER-rich reproductive tract had greater than 63 times the concentration of radiolabel in blood; the former was blocked by non-labeled competitors for ER. Uptake by non-ER-rich tissues, compared to blood, ranged from 0.7:1 (heart and lungs) to 16:1 (spleen); the omentum, however, exhibited a concentration as high as 64:1, which was not blocked by non-labeled ER ligands. Uptake by ER-rich target tissue remained high when charcoal was used to prevent reabsorption of radiolabel from the digestive tract after its biliary excretion, and when the products of biliary excretion were removed by catheterization of the common bile duct. Neither charcoal nor exteriorization of bile appeared to affect urinary clearance of the radiolabel over the time course of the experiments. Taken together with the recent development of syntheses that yield radiohalogenated sex steroid receptor ligands of high specific activity, our findings are encouraging for the potential application of radiolabeled ligands as i.p. administered pharmaceuticals. The advantage of the i.p. route is that it provides direct uptake of the pharmaceutical by free-floating clusters and individual cancer cells in ascitic fluid, as well as delivery via the circulation to vascularized intra- and/or extraperitoneal metastases.