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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Breast cancer is a highly heterogeneous disorder with regard to biologic and clinical characteristics. Identification of patients with different biologic subtypes is important both prognostically and therapeutically. The recent introduction of estrogen and progesterone receptor measurement has considerably increased our ability to identify patients with hormone-dependent tumors who are likely to respond to endocrine therapy and enjoy a longer survival. Assessment of the tumor growth fraction by autoradiographic or flow cytometric methods and measurement of EGF receptors in tumor specimens are likely to produce additional independent information on the clinical outcome of patients with breast cancer. The endocrine therapy of breast cancer has been greatly facilitated with the introduction of newer forms of therapy such as antiestrogens and aromatase inhibitors. These forms of treatments are well established, not only in patients with metastatic disease but also in selected subgroups of women with operable breast cancer following surgery. In view of its low toxicity and ease of administration, modern endocrine therapy has obviated the need for major ablative procedures such as surgical adrenalectomy and hypophysectomy. Unfortunately, duration of response and survival have not been prolonged by these newer endocrine treatments when compared with traditional hormonal therapy. Thus, new treatment strategies need to be developed, since current therapy does not cure any patient with advanced disease and at best only a small fraction of women with early breast cancer. Hormonally induced manipulation of tumor cell kinetics may provide a tool to enhance the efficacy of cytotoxic chemotherapy, in both metastatic as well as locally advanced disease. This potential approach needs to be further evaluated in prospective randomized clinical trials. Prostate cancer is the male counterpart of hormone-dependent neoplasia. Conventional therapy of this malignancy consists of surgical or medical castration. However, despite a high initial response rate, disease progression invariably occurs with poor response to secondary forms of therapy. Potential new treatment strategies currently being tested in the attempt to improve clinical outcome include simultaneous early blockade of both adrenal and testicular androgens as well as hormonally induced tumor cell growth synchronization and recruitment prior to administration of cytotoxic chemotherapy.
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PMID:Endocrine therapy of breast and prostate cancer. 266 86

Remarkable advances in the treatment of urologic malignancies have recently been made. Monoclonal antibodies selective for a variety of normal and malignant urologic tissues have been useful in defining normal antigens and tumor-associated antigens and have potential as diagnostic and immunotherapeutic agents. In renal cancer, monoclonal antibodies can define serum markers, radiolabel tumor xenografts, and assist in specific tissue diagnosis. Additionally, there is potential for these antibodies either alone or as conjugates to localize and kill tumors. Monoclonal antibodies to bladder cancer associated antigens are able to demonstrate differential antigen expression on superficial versus invasive tumors, to refine urinary cytologic diagnosis of bladder cancer, and to predict invasive recurrence of superficial cancer. Monoclonal antibodies have localized bladder tumor xenografts and can inhibit tumor growth when conjugated to radioisotopes or toxins. In prostate cancer monoclonal antibodies to prostate antigens are not usually tumor specific. Monoclonal antibodies to prostate antigen (PA) and prostatic acid phosphatase (PAP) are able to localize prostate cancer metastases. Chemotherapy-conjugated anti-PAP monoclonal antibodies have demonstrable inhibition on human prostate cancer xenografted tumor growth. Monoclonal antibodies have defined normal and tumor-associated antigens in urologic cancers and are expected to be useful in immunodiagnosis and cancer therapy in the near future.
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PMID:Diagnostic and therapeutic utility of monoclonal antibodies in urologic oncology. 267 36

The combination of a long-acting delivery system for the agonist [D-Trp6]luteinizing hormone-releasing hormone ([D-Trp6]LH-RH) with modern somatostatin analogs was studied in the Dunning R-3327H rat prostate cancer model. Microcapsules of [D-Trp6]LH-RH releasing 25 micrograms/day were injected once a month. In the first experiment the adjunct was the somatostatin analog D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH2 (RC-121), administered at a dose of 2.5 micrograms twice a day, and the therapy was continued for 70 days. Tumor volume was significantly decreased by [D-Trp6]LH-RH microcapsules or RC-121 given alone. The combination of microcapsules and analog RC-121 caused a greater inhibition of tumor growth than the single agents. Similar effects were seen when the percent increase in the tumor volume was examined. The inhibition of tumor growth caused by the [D-Trp6]LH-RH microcapsules was greater than that caused by RC-121. The combination of the two agents was again the most effective, resulting in the smallest increase in tumor volume. Tumor weights were much lower in the groups treated with microcapsules or RC-121 alone than in controls. The lowest tumor weights were obtained in the group that received the combination of [D-Trp6]LH-RH microcapsules and RC-121. Similar results were obtained in the second experiment, in which the animals were treated for a period of 83 days with microcapsules containing the somatostatin analog D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2 (RC-160) that released 5 micrograms/day and were injected twice a month alone or in combination with microcapsules of [D-Trp6]LH-RH. Microcapsules of analog RC-160 given alone significantly decreased tumor growth as measured by the final tumor volume, the percentage change from the initial tumor volume, and the reduction in tumor weight. The inhibition of tumor growth induced by [D-Trp6]LH-RH microcapsules was greater than that caused by RC-160. The most striking decrease in tumor weight and volume was obtained in animals treated with microcapsules of [D-Trp6]LH-RH combined with the delayed delivery system for RC-160. The overall response to the combination therapy could reflect the inhibition by somatostatin analogs of the proliferation of prostate cancer cells through a decrease in growth hormone and prolactin release and interference with endogenous growth factors, in addition to the main effect, which is the suppression by [D-Trp6]LH-RH of the growth of androgen-dependent tumor cells. Our results indicate that somatostatin analogs enhance the inhibitory effects of [D-Trp6]LH-RH on the growth of prostate tumors. The administration of somatostatin analogs in combination with microcapsules of [D-Trp6]LH-RH might improve clinical response in patients with advanced prostate carcinoma.
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PMID:Somatostatin analogs as adjuncts to agonists of luteinizing hormone-releasing hormone in the treatment of experimental prostate cancer. 289 Jan 64

The combination of hormonal treatment based on a long-acting delivery system for the agonist [6-D-tryptophan]luteinizing hormone-releasing hormone ([D-Trp6]-LH-RH) with the chemotherapeutic agent Novantrone (mitoxantrone dihydrochloride) was studied in the Dunning R3327H rat prostate cancer model. Microcapsules of [D-Trp6]-LH-RH formulated from poly(DL-lactide-co-glycolide) and calculated to release a controlled dose of 25 micrograms/day were injected intramuscularly once a month. Novantrone (0.25 mg/kg) was injected intravenously once every 3 weeks. Three separate experiments were carried out. When the therapy was started 45 days after transplantation and continued for 70 days, tumor volume in the presence of the microcapsules (966 +/- 219 mm3) or Novantrone (3606 +/- 785 mm3) given alone was significantly decreased compared to controls (14,476 +/- 3045 mm3). However, the combination of microcapsules and Novantrone caused a greater inhibition of tumor growth (189 +/- 31 mm3) than the single agents. Similar effects were seen when the percent increase in tumor volume was examined. Tumor volume increased 10,527 +/- 1803% for the control group. The inhibition of growth caused by the [D-Trp6]LH-RH microcapsules alone (672 +/- 153% increase in volume) was again greater than that caused by Novantrone alone (2722 +/- 421% increase). The combination of the two agents was again the most effective, resulting in an increase in tumor volume of only 105 +/- 29%. Control tumors weighed 30.0 +/- 6.5 g. Tumor weights were much less in the groups treated with either microcapsules (3.28 +/- 0.69 g) or Novantrone (19.53 +/- 3.3 g) alone. The lowest tumor weights after 70 days of treatment were obtained in the group that received the combination of [D-Trp6]LH-RH microcapsules and Novantrone (1.02 +/- 0.2 g). Testes and ventral prostate weights were significantly diminished by the administration of microcapsules of [D-Trp6]LH-RH alone or in combination with Novantrone. In both of these groups, luteinizing hormone and prolactin levels were reduced and serum testosterone was suppressed to undetectable levels. Similar results were obtained in two other experiments in which the duration of treatment was 60 or 105 days. These results suggest that the overall response could reflect the inhibition of proliferation of hormone-independent cancer cells by Novantrone in addition to the suppressive effect of [D-Trp6]LH-RH on the growth of androgen-dependent tumor cells. The administration of Novantrone in combination with microcapsules of [D-Trp6]LH-RH might produce a better clinical response than LH-RH analog alone in patients with advanced prostate carcinoma.
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PMID:Combination of a long-acting delivery system for luteinizing hormone-releasing hormone agonist with Novantrone chemotherapy: increased efficacy in the rat prostate cancer model. 294 45

The Dunning R3327 adenocarcinoma represents a model for studying prostate cancer in rats; early studies have indicated its utility for studying relationships between tumor growth, immunologic markers, and chemotherapy. Normal animals and those bearing the metastatic Dunning R3327 MAT-LyLu tumor were treated with 10, 30, and 100 mg/kg doses of cyclophosphamide (CTX) and their spleens assayed for leukocytic subset distributions using monoclonal antibodies. Tumor-bearing animals had significant reductions in helper T cell content as well as reduced helper/suppressor T cell ratios, compared to controls. These effects occurred rapidly following implantation and were not reversed by chemotherapy. When administered to both tumor- and non-tumor-bearing animals, CTX also depleted T cell populations. Despite reductions produced in all subsets, two administrations of CTX (30 mg/kg) were capable of retaining (in non-tumor-bearing animals) or restoring (in tumor-bearing) normal helper/suppressor T cell ratios. Such studies aid in identifying therapeutically effective dosages of cytotoxic drugs that minimize their deleterious effects on the immune system.
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PMID:Effect of cyclophosphamide on leukocytic subset distributions in rats carrying the Dunning R3327-MAT-LyLu prostatic adenocarcinoma. 295 10

The effects of luteinizing hormone-releasing hormone (LHRH) agonist (Zoladex) treatment on hormone-dependent rat prostate adenocarcinoma (R3327-H) were investigated based on changes in tumor volume and histology. Tumor-bearing rats were treated for 10 weeks with Zoladex in depot preparation by implantation every 2, 4, or 6 weeks. Tumor growth rate was similar in the castrated group and in the rats treated every 2 weeks with Zoladex. This growth rate was significantly slower than in animals treated with Zoladex every 6 weeks and the nontreated group. The growth rate in rats treated every 4 weeks appeared to be faster than that in the castrated animals (not significant). Changes in testosterone levels measured during Zoladex treatment correlated with tumor growth kinetics. Zoladex implantation yields effective and complete androgen deprivation only in the rats with two weekly depot renewal regimen. Tumor histology indicated that the stromal as well as the glandular epithelial cells responded to both castration and to Zoladex treatment. However, in tumors from rats treated with Zoladex every 4 and 6 weeks progressive increasing signs of restoration of normal elements, comparable to non-treated tumors were observed. These results strongly suggest that careful attention has to be paid to the timing of LHRH depot renewal in prostate cancer treatment.
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PMID:Renewal timing of long-acting depot luteinizing hormone-releasing hormone agonist (Zoladex) is critical in the treatment of hormone-dependent rat prostatic carcinoma (R3327-H). 296 Sep 58

Hormonal control of tumor growth has shifted from what was basically an empirical discipline twenty-five years ago to what is now primarily a pharmacologic and biochemical science. Early on, medical management of malignancy relied heavily on the knowledge that deprivation of steroids produced by the sex glands could result in the regression of tumors in breast cancer and prostatic cancer. Today's approach to management is focused on the way in which different steroids feed the cancer cell itself. As a result, many new hormonal agents have been developed on the basis of the knowledge that it is possible to interfere with the process of cancer growth directly at the cellular level. The biochemical rationale for the development of many of these agents is discussed.
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PMID:Hormonal agents and treatment of cancer. 300 95

Recognition of the clinical importance of prostate cancer undoubtedly was delayed by the failure of clinicians or pathologists to distinguish consistently between benign and malignant prostatic growths until well into the 19th century. White used castration for prostatic enlargements in 1895, but Huggins and Hodges first placed endocrine therapy on a rational basis in 1941. Although a number of surgeons had attempted excision of prostate cancer, Young is credited with planning and performing the first radical perineal prostatectomy in 1904. Orthovoltage irradiation and various techniques of interstitial and intracavitary radium therapy were used in the treatment of prostate cancer early in the 20th century, but it was the development of megavoltage irradiation that reopened the door to the exploration of irradiation for localized prostate cancer following World War II. Endocrine manipulation, surgery, and irradiation remain the keystones of treatment. The management of prostate cancer is controversial for several reasons: 1) The disease occurs in an age range in which competing causes of mortality are high. 2) The natural evolution of the disease is varied, often long, and not consistently predictable. 3) Long-term survival has been reported for each of the principal modes of therapy, but randomized controlled studies have been limited. Uniformity in histologic grading, clinical staging, and evaluation of response to treatment would improve the quality of the data. Predictions of host life expectancy, tumor growth rate, metastatic potential, and tumor responsiveness to irradiation and endocrine therapy would enhance the rationale of treatment.
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PMID:Consensus Development Conference on the Management of Clinically Localized Prostate Cancer. Overview: historical and contemporary. 305 May 41

Ketoconazole is a well-tolerated, synthetic, imidazole derivative currently in widespread therapeutic use against mycotic infections. Recent evidence that it depresses testosterone synthesis in humans prompted us to investigate the effects in rats of its administration alone or in combination with the gonadotropin releasing hormone superagonist analogue leuprolide. Plasma luteinizing hormone, testosterone, and ketoconazole levels as well as ventral prostate weight and tumor growth in rats bearing the androgen-dependent Dunning R3327H model of prostate adenocarcinoma were measured. Doses of 30 mg/kg twice daily of ketoconazole alone depressed plasma testosterone levels by approximately 75% to a nadir of 0.47 +/- 0.08 (SE) ng/ml on day 20 (P less than 0.001 versus basal). This effect of ketoconazole was exerted directly at the testicular level since plasma luteinizing hormone levels were not suppressed. In response, ventral prostate weight declined and growth of the Dunning R3327H tumor was retarded to rates observed in castrate controls. Leuprolide alone lowered basal testosterone levels to 0.20 +/- 0.02 ng/ml after 35 days of daily administration but persistent androgen increments after each injection (acute-on-chronic effect) were observed (i.e., to 4.41 +/- 0.62 ng/ml). The addition of ketoconazole to leuprolide inhibited the acute-on-chronic rise in testosterone to 0.33 +/- .07 ng/ml and also lowered basal testosterone levels further to 0.11 +/- 0.01 on day 10 of combined administration. Ketoconazole also blunted the response to the first injection of leuprolide from a 3-h peak level of 8.74 +/- 0.53 to 4.17 +/- 0.80 with the 40 mg/kg dose. These results indicate that combining ketoconazole with leuprolide achieves greater suppression of testosterone than either agent alone. When such protocols are applied to humans with prostate cancer, more extensive effects may be expected because of the greater sensitivity of patients than of the rodent species to these agents.
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PMID:Inhibition of testosterone production with ketoconazole alone and in combination with a gonadotropin releasing hormone analogue in the rat. 307 88

The therapy for the treatment of prostate cancer and other sex-steroid-dependent tumors based on agonists of LH-RH has been made more practical and efficacious by the development of a long-acting formulation of microcapsules of D-Trp-6-LH-RH for controlled release. Antiandrogens, which neutralize the effect of endogenous androgens, have been used also in the management of prostate cancer in man. The effects of a simultaneous administration of the antiandrogen flutamide and microcapsules of the agonist D-Trp-6-LH-RH were studied in the Dunning R-3327H rat prostate adenocarcinoma model to determine whether the combination of these two drugs might inhibit tumor growth more effectively than single agents. Microcapsules of D-Trp-6-LH-RH, calculated to release a controlled dose of 25 micrograms/day for a period of 30 days were injected intramuscularly once a month. Flutamide was administered SC at a daily dose of 25 mg/kg. The therapy was started 100 days after the tumor transplantation and continued for 60 days. Tumor weights and volumes were significantly reduced in rats treated with microcapsules or flutamide alone, but the former drug inhibited tumor growth more than the latter. The combined treatment of flutamide and microcapsules significantly decreased tumor weight and volume, but did not exert a synergistic effect on tumor growth, the reduction being smaller for the combination than for the microcapsules alone. There was a significant elevation of serum testosterone, LH, and prolactin in rats treated with flutamide. On the other hand, in rats given microcapsules of D-Trp-6-LH-RH, testosterone fell to castration levels within 7 days and remained at nondetectable values, serum LH and prolactin levels being also suppressed in this group. The combined administration of microcapsules and flutamide also significantly decreased serum testosterone to nondetectable levels by day 7 and suppressed serum LH and prolactin. Our findings raise doubts of whether the daily administration of the combination of LH-RH agonist with an antiandrogen offers an advantage over the use of microcapsules of an agonist like D-Trp-6-LH-RH alone in the treatment of prostatic carcinoma.
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PMID:Investigation of the combination of the agonist D-Trp-6-LH-RH and the antiandrogen flutamide in the treatment of Dunning R-3327H prostate cancer model. 315 27


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