Background. Cryosurgical ablation of prostate (CSAP) has gained popularity as alternative treatment for localized prostate cancer with excellent local tumor control, being performed at more than 100 centers in USA (1). But there are only isolated reports with CSAP with CSPA using for palliation of stage D prostate cancer, includingsolely to eliminate or ease local symptoms and make the patients more comfortable (2,3).
Remarkable recent advances in our understanding of the immune system and the advent of new immunostimulants, especially recombinant cytokines, now permit direct activation and regulation (direction) of immune responses as well as ways of obtaining more long-lasting immunity (4).
As it is known, IL-1 is as main cytokine vital to the proliferation and maturation of whole immune cascade (5).
Aims and Objectives. The purpose of this study is to use the combination of CSAP with cytokinotherapy by IL-1 as more guided and accordingly more effective approach to treat patients with advanced (stage D) prostate cancer. There will be attempt to eradicate the prostate cancer or treat any metastases or other symptoms arising from this disease.
Rationale and Methods. Many investigators (6,7) on the basis of the wide range of tissue effects that can be attained by cryonecrosis, expressed great expectations for the cryoimmunologic (both a specific humoral and a cellular immune response) augmentation of tumor destruction. Moreover, in advanced-stage disease- where tumor heterogeneity confounds treatment by conventional therapy and patients succumb to the direct effects of metastasis and complications associated with treatment- cryoimmune response may additionally be tumoricidal to metastases (4).
Cryoimmunisation may result in a response that may be tumoricidal as well as tumor enhancing - bidirectional (Figure 1). Primary tumor-antigen liberation lies not merely in augmentating an antitumor response but in directing (modulating) the response toward that will be tumoricidal. However further antigenic stimulation actually attenuates the immune response by an intrictic biochemical feedback mechanism. This one decreases the T cell activity, thereby self-regulating the production of interleukin- 1 and other cytokines. This idea further explains a prolongation of immune response. This a "booster" response was successfully achieved by multiple freezing of the prostate at intervals of 30 days or more (8).
But these considerations may be prevented by precryosurgical using of rec. IL-1 with pleiotropic action. Our preliminary results of immunotherapy have shown the efficacy of this modality in advanced prostate cancer (9). We have noted the preventive action of IL-1 to the whole cascade of humoral and cellular immunity to possible side-effects of basic palliative therapy- chemotherapy, radiotherapy and cryodestruction ( ).
The regime of proposed immunotherapy may be as follow: IL-1b (betaleukin), which has already got an approval from Russian National Pharmacological Comittie and now is produced by St.Petersburg State Research Institute of Highly Pure Biopreparations , - in dose 5ng/kg subcutaneously daily during 3-5 days with 1-2 days interval of resting before cryoablation . Then cryoablation of the prostate will be performed utilising the Spembly Cryosurgical Systems (LCS 3000, manufactured by Candela ,Inc.) with a standard five probe double freeze technique. Respectively we suspect to treat patients with advanced prostate cancer- T3-4,N1-2,MX/0-1. Based upon the data of immunity disturbances changing, may be repeating of systemic IL-1b course at 1 month (minimum) after cryoablation.
Moreover, in an inflammatory response, such as that initiated by cryonecrosis, the target tissue will be subjected to the action of not just only IL-1 but several cytokines as a result of chain-reaction, that may act synergistically to promote one arm of the immune response while inhibiting the other. Cytokines are pleiotropic and may function in autocrine, paracrine and endocrine manner. Developing data suggest that locally produced cytokines may arouse immunogenicity and facilitate cell-to-cell interactions and antigen presentation by inducing or enhancing expression of select membrane proteins.
According to this hypothesa, we are proposing to inject IL-1b (up to 10 ng) into tumor also followed 24 hours later by cryosurgery (Fig.1).
The initial immunological status and its consequent alterations will be evaluated by studies of systemic and local immunity .
An evaluation of this new therapeutic approach against advanced prostate carcinoma will be conducted with routine clinical evaluation (physical examination, sexual story, laboratory findings, Internationalo Prostate Symptom Score:IPSS, urodynamic pressure-flow studies) as well as stated markers of tumor progression- bone scan, prostate-specific antigen (PSA), acid phosphatase, lymph node status by CT and MRI. In addition, the newer diagnostic immunocytochemical and molecular-biological methods especially for chemo-and hormonal relapsed prostate cancer- multidrug resistance (P-glycoprotein expression by Western blotting cell lysates using specific antibodies) with determination the sensivity to Estracyt, level of androgen receptors ( exon 2-8 amplification of androgen receptors gene by
polymerase-chain reaction) and apoptosis index (tumor supressor gene p53 from paraffin-embedded prostate specimens using monoclonal antibody do7- Dako UK Ltd.) (10 ).
Expected results. One important clinical consideration is the fact that nearly all prostate cancers are at least initially sensitive to a variety of anti-neoplastic drugs. Treatment regimemens incorporating combinations of these drugs currently are the mainstay of theraoy, and can often achieve substantial reductions in tumor burden and prolongation of survival. One of the more attractive this drug is estracyt, consisting of cytotoxic as well as antiandrogen agent. Unfortunately, for many of the tumor cases, recurrence with drug-resistant tumors often follows chemo-and hormonal therapy-induced remissions. It seems likely that our new approach that attempt to generate T-cell mediated anti-tumor immunity will need to occur in the context of existing remission including systemic chemo- and hormonotherapies. Many of these agents are themself highly immunosuppressive. Nevertheless, our preliminary results have demonstrated that in the setting of cryoimmunmotherapy with basic adjuvant therapy by estracyt resulting in a combined efficiacy that exceeds either modality ( 9 ). Additionally, human recombinant IL-1b has prevented significantly myelosuppression and other adverse effects of estracyt, allowing to increase its doses up to maximum efficacy. Finally, from the bidirectional nature of the cryoimmune response exhibited, evaluation and elucidation of the role of local and systemic cytokinotherapy before and after cryosurgery and their possible
regulation should prove most enlightening. We hope this approach allows us to improve the CSAP efficacy and inhibit the metastases growth in the combinative treatment of advanced prostate cancer.
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