Regression of prostatic cancer following sequential cryotherapy to the prostate

Cryoablation triggers type I interferon-dependent antitumor immunity and potentiates immunotherapy efficacy in lung cancer

BACKGROUND

Cryoablation is a minimally invasive option for patients with medically inoperable non-small cell lung cancer (NSCLC) and can trigger abscopal immune-regulatory effects. However, it remains unclear how cryoablation affects the host-level immune response in NSCLC. In this study, we investigated the local and systemic immunological effects of cryoablation and the potential of combining cryoablation with programmed cell death protein 1 (PD-1) blockade to boost immunotherapy efficacy in NSCLC.

METHODS

We first investigated systemic immunological effects induced by cryoablation in patients with early-stage NSCLC. Subsequently, we explored cryoablation-induced antitumor immunity and the underlying biological mechanisms using KP (Kras G12D/+, Tp53 -/-) mutant lung cancer cell allograft mouse models. Moreover, the synergistic efficacy of cryoablation and PD-1 blockade was explored in both mouse models and patients with unresectable NSCLC.

RESULTS

We found that cryoablation significantly increased circulating CD8+ T cell subpopulations and proinflammatory cytokines in patients with early-stage NSCLC. In lung cancer cell allograft mouse models, we demonstrated that cryoablation resulted in abscopal growth inhibition of contralateral, non-ablated tumors. Integrated analysis of bulk, single-cell RNA and T cell receptor (TCR) sequencing data revealed that cryoablation reprogrammed the intratumoral immune microenvironment and increased CD8+ T cell infiltration with higher effector signature, interferon (IFN) response, and cytolytic activity. Mechanistically, cryoablation promoted antitumor effect through the STING-dependent type I IFN signaling pathway, and type I IFN signaling blockade attenuated this antitumor effect. We also found that the combination of PD-1 blockade with cryoablation further inhibited tumor growth compared with either treatment alone in an allograft mouse model. Moreover, the combination therapy induced notable tumor suppression and CD8+ T cell infiltration in patients with unresectable NSCLC.

CONCLUSIONS

Our results provide mechanistic insights into how cryoablation triggers the antitumor immune effect in lung cancer, thereby potentiating programmed cell death ligand 1 (PD-L1)/PD-1 blockade efficacy in the clinical treatment of NSCLC.

Radiotherapy, photodynamic therapy, and cryoablation-induced abscopal effect: Challenges and future prospects

Local therapy modalities such as radiation therapy, photodynamic therapy, photothermal therapy, and cryoablation have been used to treat localized tumors for decades. The discovery of the abscopal effect causes a paradigm shift where local therapy also causes systemic effects and leads to the remission of nonirradiated tumors. The abscopal effect of radiation therapy, alone or in combination with other treatments, has been extensively studied over the last six decades. However, the results are unsatisfactory in producing robust, reproducible, and long-lasting systemic effects. Although immunotherapy and radiation therapy are promising in producing the abscopal effect, the abscopal effect's mechanism is still unclear, owing to various factors such as irradiation type and dose and cancer type. This article reviews the research progress, clinical and preclinical evidence of the abscopal effect by various local therapies alone and in combination with chemotherapy and immunotherapy, case reports, and the current challenges in producing the abscopal effect by various local therapies, focusing on radiotherapy, photodynamic therapy, cryoablation, and the prospects for obtaining a robust, reproducible, and long-lasting abscopal effect.

Cryoablation reshapes the immune microenvironment in the distal tumor and enhances the anti-tumor immunity

As one of the local treatments, cryoablation plays an increasingly important role in the comprehensive treatment of malignant tumors with its advantages of less trauma, high reproducibility, and minimally invasive. Activation of anti-tumor immunity, another characteristic of cryoablation, has attracted more and more attention with the extensive application of immunotherapy. Unfortunately, the mechanism by which cryoablation enhances anti-tumor immunity is still unclear. In this study, we applied a multi-omics approach to investigate the effects of local cryoablation in the distal tumor microenvironment. The results revealed that large amounts of tumor antigens were released post-cryoablation, leading to a sterile inflammatory response in distant tumors. During this period, activated lysosome-related pathways result in over-expression of SNAP23 (Synaptosome associated protein 23) and STXBP2 (Syntaxin binding protein 2), activation of immune effector cells, suppression of the release of immunosuppressive factors, and finally enhancement of anti-tumor immunity, which shows a broad prospect in combined immunotherapy.

Distant Resolution of Actinic Keratosis following Cryosurgery: An Unusual Phenomenon

Early after the introduction of cryosurgery to clinical practice, there were reports of metastasis regressing after cryosurgery of a primary tumour, mainly prostate and breast cancer, suggesting a systemic immunological effect to a local reaction. Colleagues within dermatology have occasionally experienced similar systemic effects following cryosurgery. However, published reports of such cases are lacking. In this case, we report a photographed distant resolution of an actinic keratosis (AK) on 68-year-old woman's arm following cryosurgery of another AK on the same arm.

Rate of Freeze Impacts the Survival and Immune Responses Post Cryoablation of Melanoma

The emergence of ablative therapies has revolutionized the treatment of inoperable solid tumors. Cryoablation stands out for its uniqueness of operation based on hypothermia, and for its ability to unleash the native tumor antigens, resulting in the generation of anti-tumor immune responses. It is not clearly understood how alterations in the rate of freeze impact the immune response outcomes. In this study, we tested fast freeze and slow freeze rates for their locoregional effectiveness and their ability to elicit immune responses in a B16F10 mouse model of melanoma. Tumor bearing mice treated with fast freeze protocol survived better than the ones treated with slow freeze protocol. Fast freeze resulted in a higher magnitude of CD4+ and CD8+ T-cell responses, and a significantly extended survival post re-challenge. Thus, fast freeze rate should be applied in any future studies employing cryoablation as an in vivo vaccination tool in conjunction with targeted immunotherapies.

Cryoablation and Immunotherapy: An Enthralling Synergy to Confront the Tumors

Treatment of solid tumors by ablation techniques has gained momentum in the recent years due to their technical simplicity and reduced morbidity as juxtaposed to surgery. Cryoablation is one of such techniques, known for its uniqueness to destroy the tumors by freezing to lethal temperatures. Freezing the tumor locally and allowing it to remain in situ unleashes an array of tumor antigens to be exposed to the immune system, paving the way for the generation of anti-tumor immune responses. However, the immune responses triggered in most cases are insufficient to eradicate the tumors with systemic spread. Therefore, combination of cryoablation and immunotherapy is a new treatment strategy currently being evaluated for its efficacy, notably in patients with metastatic disease. This article examines the mechanistic fabric of cryoablation for the generation of an effective immune response against the tumors, and various possibilities of its combination with different immunotherapies that are capable of inducing exceptional therapeutic responses. The combinatorial treatment avenues discussed in this article if explored in sufficient profundity, could reach the pinnacle of future cancer medicine.

CD8+ T-Cell Density Imaging with 64Cu-Labeled Cys-Diabody Informs Immunotherapy Protocols

Purpose: Noninvasive and quantitative tracking of CD8+ T cells by PET has emerged as a potential technique to gauge response to immunotherapy. We apply an anti-CD8 cys-diabody, labeled with 64Cu, to assess the sensitivity of PET imaging of normal and diseased tissue.Experimental Design: Radiolabeling of an anti-CD8 cys-diabody (169cDb) with 64Cu was developed. The accumulation of 64Cu-169cDb was evaluated with PET/CT imaging (0, 5, and 24 hours) and biodistribution (24 hours) in wild-type mouse strains (n = 8/group studied with imaging and IHC or flow cytometry) after intravenous administration. Tumor-infiltrating CD8+ T cells in tumor-bearing mice treated with CpG and αPD-1 were quantified and mapped (n = 6-8/group studied with imaging and IHC or flow cytometry).Results: We demonstrate the ability of immunoPET to detect small differences in CD8+ T-cell distribution between mouse strains and across lymphoid tissues, including the intestinal tract of normal mice. In FVB mice bearing a syngeneic HER2-driven model of mammary adenocarcinoma (NDL), 64Cu-169cDb PET imaging accurately visualized and quantified changes in tumor-infiltrating CD8+ T cells in response to immunotherapy. A reduction in the circulation time of the imaging probe followed the development of treatment-related liver and splenic hypertrophy and provided an indication of off-target effects associated with immunotherapy protocols.Conclusions: 64Cu-169cDb imaging can spatially map the distribution of CD8+ T cells in normal organs and tumors. ImmunoPET imaging of tumor-infiltrating cytotoxic CD8+ T cells detected changes in T-cell density resulting from adjuvant and checkpoint immunotherapy protocols in our preclinical evaluation. Clin Cancer Res; 24(20); 4976-87. ©2018 AACR.

Immunological effect of local ablation combined with immunotherapy on solid malignancies

Recent comprehensive investigations clarified that immune microenvironment surrounding tumor cells are deeply involved in tumor progression, metastasis, and response to treatment. Furthermore, several immunotherapeutic trials have achieved successful results, and the immunotherapeutic agents are available in clinical practice. To enhance their demonstrated efficacy, combination of immunotherapy and ablation has begun to emerge. Local ablations have considerable advantages as an alternative therapeutic option, especially its minimal invasiveness. In addition, local ablations have shown immune-regulatory effect in preclinical and clinical studies. Although the corresponding mechanisms are still unclear, the local ablations combined with immunotherapy have been suggested in the treatment of several solid malignancies. This article aims to review the published data on the immune-regulatory effects of local ablations including stereotactic body radiotherapy, cryoablation, radiofrequency ablation, and high-intensity-focused ultrasound. We also discuss the value of local ablations combined with immunotherapy. Local ablations have the potential to improve future patient outcomes; however, the effectiveness and safety of local ablations combined with immunotherapy should be further investigated.

Optimized magnitude of cryosurgery facilitating anti-tumor immunoreaction in a mouse model of Lewis lung cancer

BACKGROUND

Cryosurgery has reemerged as a less invasive local treatment with possible immune-regulatory effects. However, the optimal magnitude of cryosurgery for achieving immune-regulatory responses at abscopal tumor sites remains unclear. We aimed to investigate appropriate magnitude of cryosurgery for this goal using a mouse model.

METHODS

C57BL/6J mice were inoculated with Lewis lung carcinoma cells or B16 melanoma cells in bilateral flanks. The left-sided tumor was cryoablated with repeated freeze/thaw cycles either once, twice, or thrice. The peritumoral injections of LPS were performed. Abscopal tumor volumes were measured, immunohistochemistry was performed for CD4, CD8, Foxp3, and Ki-67, and proinflammatory cytokines were measured in lavage fluid of cryoablated tumor.

RESULTS

The growth rate of the abscopal tumor was slowest in the Cryosurgery ×2 group among the five experimental groups. The proportions of CD4(+) T cells and CD8(+) T cells in the abscopal tumor were also significantly higher in the Cryosurgery ×2 group. The levels of IL-1β, IL-2, IL-6, IL-12β, IFN-γ, and TNF-α in the peritumoral lavage fluid in Cryosurgery ×2 + LPS group were significantly increased compared with the other groups.

CONCLUSIONS

This study suggested that achievement of approximately 73 % damaged area in the cryoablated tumor by two cycles of cryosurgery generates the most favorable immune-regulatory response for abscopal tumors via activation of anti-tumor immune cells as well as increased secretion of proinflammatory cytokines.

Thermal Ablative Therapies and Immune Checkpoint Modulation: Can Locoregional Approaches Effect a Systemic Response?

Percutaneous image-guided ablation is an increasingly common treatment for a multitude of solid organ malignancies. While historically these techniques have been restricted to the management of small, unresectable tumors, there is an expanding appreciation for the systemic effects these locoregional interventions can cause. In this review, we summarize the mechanisms of action for the most common thermal ablation modalities and highlight the key advances in knowledge regarding the interactions between thermal ablation and the immune system.

Structural and immunological effects of skin cryoablation in a mouse model

Cryoablation is therapeutically applied for various disorders in several organs, and skin diseases are typical targets as this cryotherapy has been widely used for viral warts, benign tumors, and actinic keratosis. The main mechanisms of cryoablation consist of direct freezing effect on skin constituents, thrombosis formation in microcirculation, and subsequent immunological responses. Among them, however, the immunological mechanism remains unelucidated, and it is an issue how the direct freezing injury induces immunological consequences. We established a mouse cryoablation model with liquid nitrogen applied to the shaved back skin, and used this system to study the immunological excitement. After application of liquid nitrogen, the thermal decrease ratio was -25°C/sec or less and the lowest temperature was less than -100°C, which was sufficient to induce ulceration. Destruction of cornified layer and necrosis of epidermal cells were observed in transmission electron microscopy image, and increased transepidermal water loss and skin permeability were detected by the functional measurements. By flow cytometry, antigen-presenting dendritic cells (DCs), including PDCA1+B220+CD19- plasmacytoid DCs (pDCs) and CD11c+ myeloid DCs, as well as neutrophils and macrophages were increased in subcutaneous tissue. In parallel, the mRNA expressions of interferon α1 which are known as pDC-producing cytokines, was elevated. We also found marked degranulation of mast cells, providing a possibility that released histamine attracts pDCs. Finally, FITC migration assay revealed that pDCs and CD11c+ DCs emigrated from the cryoablated skin to the draining lymph nodes. Our study suggests that cryoablation induces destruction of the barrier/epidermis, accumulation of pDCs and CD11c+ DCs to the skin, and migration of DCs to regional lymph nodes. Viral elements or tumor cell lysates released from damaged keratinocytes may stimulate the DCs, thereby leading to antiviral or antitumor effect.

Thermal ablation of tumours: biological mechanisms and advances in therapy

Minimally invasive thermal ablation of tumours has become common since the advent of modern imaging. From the ablation of small, unresectable tumours to experimental therapies, percutaneous radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation have an increasing role in the treatment of solid neoplasms. This Opinion article examines the mechanisms of tumour cell death that are induced by the most common thermoablative techniques and discusses the rapidly developing areas of research in the field, including combinatorial ablation and immunotherapy, synergy with conventional chemotherapy and radiation, and the development of a new ablation modality in irreversible electroporation.

Rate of freeze alters the immunologic response after cryoablation of breast cancer

BACKGROUND

Cryoablation has garnered significant interest as a treatment for solid tumors including breast cancer for both its local effects and potential in stimulating an antitumor immune response. We sought to examine the impact that variances in technique might have on the immune response and examine the mechanism by which cryoablation may stimulate an antitumor immune response.

MATERIALS AND METHODS

Balb/c mice with established 4T1 mammary carcinomas were treated by cryoablation at either a high rate of freeze or low rate of freeze, or by surgical excision, after spontaneous metastases occurred. Tumor-draining lymph nodes (TDLN) were excised at 1 week for EliSPOT assay and immunophenotyping. Mice were followed after treatment for enumeration of pulmonary metastases and survival.

RESULTS

Compared with surgical excision, cryoablation using a high freeze rate resulted in a significant increase in tumor-specific T cells in the TDLN, a reduction in pulmonary metastases, and improved survival. However, cryoablation using a low freeze rate resulted in an increase in regulatory T cells, a significant increase in pulmonary metastases, and decreased survival.

CONCLUSIONS

Cryoablation of breast cancer in mice can generate a tumor-specific immune response that can eradicate systemic micrometastases and improve outcome compared with surgical excision; however, the technique used to freeze the tissue may alter the immune response from stimulatory to suppressive.

Cyclophosphamide unmasks an antimetastatic effect of local tumor cryoablation

Cryoablation of a solitary tumor mass releases intact tumor antigens and can induce protective antitumor immunity but has limited efficacy in the treatment of established metastatic cancer. Cyclophosphamide (Cy), an anticancer drug, selectively depletes regulatory T cells (T(reg)s) and attenuates suppression of antitumor immunity. We used a BALB/c mouse model of metastatic colon cancer to investigate the systemic antitumor effects of in situ cryotherapy alone or in combination with 200 mg/kg i.p. Cy. When combined with Cy, cryoablation was significantly more effective than either surgical excision or cautery at inducing systemic antitumor immunity, resulting in the cure of a fraction of animals with established metastatic disease and resistance to tumor rechallenge. Lymphocytes from cured animals contained an expanded population of tumor-specific, interferon-gamma producing T cells and transferred antitumor immunity to naive recipients. Depletion of CD8(+) cells significantly impaired the adoptive transfer of antitumor immunity. Furthermore, treatment with Cy and cryoablation was associated with a significant decrease in the ratio of regulatory to effector CD4(+) T cells. The combination of tumor cryoablation and Cy induces potent, systemic antitumor immunity in animals with established metastatic disease.

Cryo-immunology: a review of the literature and proposed mechanisms for stimulatory versus suppressive immune responses

The use of cryosurgery to ablate tumors is expanding, primarily due to its technical ease and minimal morbidity. A potential secondary advantage to the in situ freezing of malignant disease is the cryo-immunologic response, the generation of an anti-tumor immune response triggered by the natural absorption of the malignant tissue. While initially proposed based on clinical observations of distant disease regressing after cryoablation of a primary tumor, results from preclinical studies have been mixed and the existence of a cryo-immunologic response has been controversial. Recent studies have shed light on the potential mechanism by which cryoablation may modulate the immune system, also reveals that both immunostimulatory and immunosuppressive responses may be triggered. This article reviews the existing evidence regarding tumor cryo-immunology and puts forward hypotheses regarding patient, tumor and technical factors that may influence the resultant immune response and warrant further investigation.

Cryoablation and resection influences patient survival for soft tissue sarcomas: impact on survivorship and local recurrence

Cryosurgical ablation has been used successfully for treating various carcinomas and bone tumors; however, few studies report the use of cryosurgery followed by tumor resection for the treatment of soft tissue sarcomas. We evaluated local recurrence, progression of disease, histologic necrosis from the cryoablation, complications, patient survival, and functional outcomes using this approach. We retrospectively reviewed 38 patients with no prior treatment for their neoplasm who underwent cryosurgery followed by wide excision of soft tissue sarcomas. Three patients developed local recurrence. Sixteen patients had evidence of more than 95% tumor necrosis, and 11 of these had 100% histologic necrosis. We observed a difference in overall survival and disease-free survival based on the adequacy of freezing process. Patients with more than 95% necrosis had a survival rate of 94% at 2 years and 86% at 5 years, while those with less than 95% necrosis survived 53% at 2 years and 34% at 5 years. Complications included transient neuropraxia (13%), superficial wound infections (8%), and seroma (21%). Cryosurgical ablation appears a safe and effective method of devitalizing tumor cells of soft tissue sarcomas.

Cryosurgical ablation of soft tissue sarcomas: a phase I trial of feasibility and safety

BACKGROUND

Cryosurgery is a therapeutic method of treating neoplastic tissue by freezing in situ to achieve devitalization. Cell death results from exposure to severe cold (below -40 degrees C for at least 1 minute) as well as from the process of freezing and thawing, which disrupts cellular integrity. Modern cryosurgical technique involves insertion of hollow probes into the tumor, through which circulating liquid nitrogen and gaseous nitrogen can achieve tissue and tumor freezing and thawing for tumor control. Cryoablation is now a recognized approach to the treatment of various malignant tumors, and it is generally well tolerated. This method has been used only sporadically to date in the treatment of patients with soft tissue sarcomas.

METHODS

The purpose of this study was to assess the feasibility and safety of cryosurgical ablation of soft tissue sarcomas utilizing a cryoprobe system. Twelve patients with soft tissue tumors of the extremity were included in this Institutional Review Board-approved protocol. Cryoablation was performed by inserting cryoprobes into the tumors, through which liquid nitrogen and gaseous nitrogen were pumped to achieve two freeze/thaw cycles. The entire process was monitored with intraoperative ultrasonography. All patients had subsequent resection of the residual tumor. Patients were monitored clinically and metabolically for toxicity.

RESULTS

Cryoablation was successfully performed on all 12 patients. Complications included peripheral nerve palsy (in 3 patients) and serous wound drainage (in 3 patients). There were no cases of wound infection, deep venous thrombosis, pulmonary embolism, wound dehiscence, skin slough, or metabolic abnormalities. All 3 cases of peripheral nerve palsy showed signs of recovery, 2 within 1 week and 1 within 4 months.

CONCLUSIONS

Cryosurgical ablation of soft tissue sarcomas is technically safe and feasible. This method can be used in conjunction with other modalities in the treatment of patients with these tumors. The complications associated with cryoablation of sarcomas are minor or transient, and the procedure is well tolerated by patients. The role of cryosurgery in the management of soft tissue sarcomas needs to be elucidated as more data regarding its safety and effectiveness become available.

History of cryosurgery

The use of freezing temperatures for the therapeutic destruction of tissue began in England in 1845-51 when James Arnott described the use of iced salt solutions (about-20 degrees C) to freeze advanced cancers in accessible sites, producing reduction in tumor size and amelioration of pain. Improved freezing techniques were possible early in the 1990s when solidified carbon dioxide came into use and later when liquid nitrogen and nitrous oxide became available. Nevertheless, cryotherapy was a minor technique, used only for the accessible lesions of skin and mucosa. With the development of modern cryosurgical apparatus by Cooper in 1961, a resurgence of interest in cryosurgery was initiated and techniques for diverse clinical conditions, including visceral cancer, evolved, After the initial widespread clinical trials matured in the 1970s, some applications of the technique fell into disuse while others became standard treatment. Late in the 1980s, further improvements in apparatus and imaging techniques have permitted increased clinical use in neoplastic disease, including visceral cancer.

Cryoablation for carcinoma of the prostate

Percutaneous transperineal cryoablation of the prostate is now available in the armamentarium for treatment of prostate cancer. Technical advances in real-time transrectal imaging of the prostate and improvements in cryosurgical equipment have brought this modality into the limelight of available prostate cancer management. Cryosurgery can be offered to many patients with prostate cancer. However, the main indications for its use include primary treatment for localized disease, salvage therapy after failure of traditional methods, and relief of local symptoms. A historical background, description of the technique, and clinical experience at several medical centers including the University of California San Diego, Allegheny General Hospital, University of Texas M.D. Anderson Cancer Center, and Crittenton Hospital, are presented.

Transrectal ultrasound-guided transperineal cryoablation in the treatment of prostate carcinoma: preliminary results

PURPOSE

We studied ultrasound-guided percutaneous cryoablation for treatment of prostate carcinoma.

MATERIALS AND METHODS

Our series includes 83 individuals who underwent transrectal ultrasound-guided transperineal percutaneous cryoablation of the prostate. Prostate specific antigen levels, biopsy results and complications were assessed at 3 months.

RESULTS

Of 61 biopsies 8 (13.1%) were positive for carcinoma (half showed stage D disease). Of patients with stages T1 to T3 cancer 92.6% were free of disease at 3 months. Prostate specific antigen levels were significantly decreased by an average of 1.90 ng./ml. (p < 0.05). Major complications were infrequent, including bladder perforation in 1 patient, urethral strictures in 3, bladder outlet obstruction in 2 and partial incontinence in 2. Impotence was frequent but transient.

CONCLUSIONS

Transrectal ultrasound-guided transperineal percutaneous cryoablation of the prostate produces few major complications and appears at 3 months to be effective in eradicating local prostate tumors. Longer followup is required to test the original hypothesis.

Management of oral squamous cell carcinoma in situ with topical 5-fluorouracil and laser surgery

Oral squamous cell carcinoma in situ has been described as a relatively rare lesion. However, difficult decisions with respect to clinical management of the lesion in this location parallel those reported for other mucosal sites, such as the cervix or the larynx. The lesion, though superficial, may extend over a large area of tissue, and attempts at irradication with surgery or radiation therapy may be associated with a great deal of morbidity. However, the risks in deferral of treatment while "watchfully waiting" may also be unacceptable. A method and rationale for management of oral squamous cell carcinoma in situ with the use of topical 5-fluorouracil and carbon dioxide laser are described in this article. A technique for using an intraoral prosthesis to potentiate drug delivery is also described. Though morbidity can be very significantly reduced, patient compliance is an important consideration for success with this protocol.

Characterisation of suppressor cells generated following cryosurgery of an HSV-2-induced fibrosarcoma

Cryosurgery of a primary HSV-2-induced hamster fibrosarcoma resulted in the generation of a population of suppressor cells. These cells were detectable in the spleen 1-10 days post-cryosurgery by their ability to suppress the proliferation of immunocompetent splenic T-lymphocytes following exposure to concanavalin A (Con A). The spleens of tumour-bearing (t.b.) animals which received cryosurgery 3 days previously displayed gross splenomegaly due to the generation of large numbers of highly proliferative erythroblasts. The erythroblast cells were unlikely to be the source of suppression since time course studies have demonstrated the presence of suppressor cells before and after their appearance in the spleen. The erythroblasts therefore probably reflected a response by the host to regenerate the erythrocytes lost during surgery and their presence was independent of the appearance of suppressor cells. Characterisation of the suppressor cell has revealed it to be non-adherent and esterase negative making it unlikely to be of macrophage (MO) lineage. This was confirmed by the ability of splenic MOs from day 3 t.b. cryosurgery-treated animals to completely restore Con A-dependent T-lymphocyte proliferation following MO depletion. As nylonwool column-eluted cells are able to suppress Con A-dependent T-lymphocyte proliferation, it seemed unlikely that B-lymphocytes play a role in cryosurgery-induced immunosuppression. These findings suggest that cryosurgery of a t.b. animal results in the generation of a population of T-lymphocytes capable of suppressing Con A-dependent T-lymphocyte proliferation, and infers that these cells contribute to the inferior prognosis following cryosurgery as compared to excision of a metastatic tumour.

Immunological response of regional lymph nodes after tumor cryosurgery: experimental study in rats

Seven days after inoculation of metastasizing rat mammary tumor No. 1 into the thigh of 5-week-old female Sprague-Dawley rats, the tumor was treated cryosurgically by two-cycle freezing and by contact methods at -170 degrees C. Weights of the thymus and the spleen, histological findings of the lumbar lymph nodes, phytohemagglutinin (PHA)-induced blastogenesis of lymphocytes obtained from the lumbar lymph nodes and peripheral blood, and resistance rate to tumor rechallenge were examined 1, 3, 6, 10, and 17 week(s) after cryosurgery, with the following results: Thymus weight gradually decreased by 3 weeks after cryosurgery, while spleen weight increased by 1 week, recovering the preoperative level at 6 weeks. Paracortical hyperplasia of the lumbar lymph nodes markedly increased in 1 week and sinus histiocytosis increased after 3 weeks, both remaining at high values until 10 weeks, while germinal center hyperplasia showed a high value at 3 weeks and thereafter decreased gradually. PHA-induced blastogenesis of the lumbar lymph nodes significantly increased 1 week after cryosurgery and remained at its high value until 10 weeks. PHA-induced blastogenesis of peripheral lymphocytes showed the lowest value at 3 weeks and then significantly increased at 6 weeks. Resistance rate to rechallenge showed the lowest value at 3 weeks, reaching the highest level 10 weeks after cryosurgery. From the above results, it was suggested that anti-tumor immunity (resistance to tumor rechallenge) induced by cryosurgery was at the lowest level at 3 weeks after cryosurgery, and gradually increased starting at 6 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryolumpectomy for breast cancer: an experimental study

The effects of cryosurgical procedures and surgical excision in preventing the local recurrence of mammary adenocarcinoma were studied in BALB/cfC3H mice carrying syngeneic, virus-induced mammary adenocarcinomas transplanted into the fourth mammary fat pad. In this report we present evidence demonstrating that cryosurgical procedures involving multiple freeze-thaw cycles followed by tumor excision markedly reduce the local recurrence rate of mouse mammary cancer. Surgical resection without cryotreatment resulted in an 80% local recurrence rate; in contrast, cryotreatment consisting of three freeze-thaw cycles before excision prevented local tumor recurrence in 70% of the animals. The use of cryotherapy and local excision (cryolumpectomy) in the treatment of human breast cancer is discussed.

Specific immunological stimulation induced by cryosurgery in patients with squamous-cell carcinoma of the oral cavity

Following earlier personal studies indicating that cryosurgery stimulates several non-specific immunological parameters, mainly those of the cell-mediated component, in patients with squamous-cell carcinoma of the oral cavity, inhibition of leukocyte migration (evaluated by means of the LIF test) was investigated, using a heterologous squamous-cell tumour extract, before and 7 and 14 days after a single cryotherapy session in 14 patients (11 in stages I and II, 3 in stages III and IV). Increased inhibition was observed after 7 days in 8 subjects (57.2%)-72.7% in stage I-II patients. In two cases, reactivity appeared for the first time. In 7/8 cases, this increase persisted, though at lower levels, until the 14th day. The conclusion is drawn that cryosurgery can stimulate specific delayed hypersensitivity in stage I-II squamous-cell carcinoma of mouth.

Immunotherapy of prostate cancer: a review

Tumors are antigenic and patients can mount an immune response against their tumors. Prostate cancer patients are sensitized to their malignancies and immunotherapeutic efforts have been successful. As with other tumors, it is unlikely that immunotherapy alone will be curative, but will play a role in combination therapy along with surgery, radiation, and chemotherapy. But before its rightful place can be delineated, additional clinical and laboratory studies must be completed.

Cryotherapy

Since 1969 cryosurgical perineal destruction of the prostate has been developed at the University of Iowa for treatment of patients with prostatic cancer. The technique of this procedure has been the subject of previous reviews. This is a summary of our experience of patient survival and the effect on local prostatic cancer growth in those patients with various stages of the disease subjected to perineal cryosurgical destruction of their cancer. We also report briefly on our experience in the laboratory where the Dunning tumor model is used to study the effect of cryosurgery as well as combinations of immunological modifications.

Humoral immunity following double-freezing of the prostate in patients with prostatic cancer

In these studies, 10 patients with a confirmed histological diagnosis of stage C and D carcinoma underwent double-freezing of the prostate. The clinical courses in the first group (five patients) were favorable. In the second group (two patients), death by cachexia occurred due to the cancer. In the third group (three patients), death 4 weeks after the second cryosurgery suggests the effects of cryoshock. In the first and second groups, the results of the immunological examinations after the second freezing did not attain the predicted levels. Comparing the results of the third group with those of the first and second groups the primary differences was that the percentages of gamma-globulins and IgE were higher in the third group preoperatively. These findings suggest that patients with high percentages of gamma-globulin and high IgE levels are contraindicated for cryosurgery of the prostate.

Effect of cryosurgery of the prostate in serum gonadotropin levels in prostatic cancer

Pituitary gland response to releasing hormone using the LH-RH loading test before and 4 weeks after cryosurgery of the prostate was investigated in eight patients with advanced prostatic carcinoma. In pre- and postoperative comparisons of all patients, there were no significant differences detected before and after surgery. But pituitary response to the releasing hormone was compared before and after the surgery in each of the patients; in one, depression and facilitation of FSH and LH secretion, respectively, were observed and there was a variation in the response of gonadotropin in each patient. Although the number of observable patients is still too low to draw any definite conclusions from the test results, one possible interpretation is that cryosurgery of the prostate may influence hormonal secretion from the pituitary gland.

Immunological aspects of cryosurgery in general surgery

Existence and verification of the cryoimmunologic reaction are established in basic experiments and clinical studies. However, the most effective condition in which to elicit cryoimmunologic reaction is still unknown. Evidence suggests the necessity to intensify cryoimmune reaction, if we intend to use this as one of the specific immunotherapies clinically. Establishment of criteria to select patients receiving cryosurgery is another pending question. It is important to assess the patient's immunity or immunological competence prior to cryosurgery, thereby preventing immunologically induced aggravation after cryosurgery. Twelve years of clinical experience in cryosurgery was presented and analyzed. Overall 3-year survival in the primary cancer patients was 33.3%, and 5-year survival was 17.7%. It is our aim to achieve the most beneficial effects of cryosurgery for the patients with malignancies which would otherwise be difficult to treat by conventional means.

Sandwich radiotherapy (3,000 and 4,500 rads) around radical retropubic prostatectomy for stage C prostatic carcinoma

Supervoltage external radiotherapy has been sandwiched around radical retropubic prostatectomy as a potentially curative procedure for Stage C or D1 adenocarcinoma of the prostate. Preoperatively, 3,000 rads were delivered to the pelvis and prostate by approximately 18 by 20 cm. AP-PA opposing ports over a three-week period. After three weeks' rest, radical retropubic prostatectomy was done. After three weeks' postoperative recovery, additional radiotherapy was delivered as follows: 2,000 rads to the pelvis and prostatic fossa by AP-PA opposing ports, plus 2,500 rads to the prostatic fossa alone by 360 degree rotation, plus 4,500 rads to the abdominal periaortic-caval lymph node area. Fifteen cases have been followed for up to five and one-half years to date without serious complications of the therapy and without demonstrable recurrent or residual tumor in the pelvis.

Overview of past and current philosophy of prostatic cancer

Carcinoma of the prostate is the second most common cancer in men, yet no significant change in overall survival has occurred since the original description of the results of castration by Huggins and Hodges. Many important questions about the disease remain unanswered. The cause of prostatic cancer is unknown, and few specific environmental or viral agents have been linked with the tumor. Increased recognition of the importance of frequent digitial rectal examination has resulted in more tumors being diagnosed in early stages. Developments in sonography suggest that it may be useful in detecting the presence of prostatic cancer and whether extraprostatic extension has occurred. Recent inprovements in the sensitivity of prostatic acid phosphatase assays have been made, but their use as a screening tool remains limited. In patients with clinical stage B lesions that are microscopically confined to the prostate, treatment by radical prostatectomy appears to confer greatest survival. The exact role of radiotherapy remains to be defined. However, when the tumor extends beyond the prostate and is localized to the pelvis, external beam ro interstitial radiation is appropriate. Pelvic lymphadenectomy has significant morbidity, but less invasive methods of pelvic nodal evaluation are less accurate. Lymphadenectomy has not been shown to have any therapeutic effect. Whether hormonal therapy improves survival needs further investigation, and efforts must continue to develop means of predicting hormonal responsiveness. Those patients unlikely to respond to hormonal therapy should be treated with early chemotherapy.

Adjuvant immunotherapy with bacillus Calmette-Guérin in prostatic cancer

Ninety-two patients with histologically proved prostatic cancer were studied. Forty-six patients were treated with bacillus Calmette-Guérin (BCG) adjuvant immunotherapy, and 46 other patients, matched for stage and hormone therapy, served as controls. Survival from the time of histologic diagnosis was sixteen and one-half months longer (thirty-seven and one-half versus twenty-one months) in the BCG-treated patients. There was no mortality and only minimal morbidity. Changes in some immunologic parameters (white blood cell count, skin tests) suggest an immune response.

Cryosurgery: theory and application to head and neck neoplasia

While surgery and radiation therapy remain the time-tested modalities for the treatment of cancer in the head and neck, recent experimental and clinical experience has documented the effectiveness of cryosurgery as an adjunct in the treatment of selected neoplasms in individual patients. A review is provided of the theory of freezing as a method of cell destruction, and experimental and clinical experience illustrate the principles and application of cryosurgery to head and neck tumors.

Immunologic and morphologic effects of cryosurgery of the monkey (macaque) prostate

A reduction in size of the Macaque prostate following single and multiple in situ freezings was accompanied by histologic alterations, which occurred predominately in the caudal lobe and were characterized by what appeared to be specific periacinar foci of lymphocytic infiltrates. These lymphocytes were observed to infiltrate onto acinar epithelial cells, resulting in their subsequent separation from the basal lamina and epithelial destruction. Other histologic alterations were in consonance with studies of the prostate following cryosurgery by others. Circulating antibodies specific for prostate were present in only one of the seven animals at the time at which these histologic observations were made. These observations suggest the possible development of a cellular immunologic response following cryosurgery of the prostate. The relevancy of these observations to those obtained following cryoprostatectomy in man and other species is considered. Pending confirmation, they may be of potential significance in providing an explanation of reported cases of eradication of human prostatic carcinomas following cryotherapy.

Biopsy and clinical course after cryosurgery for prostatic cancer

Open perineal cryosurgical prostatectomy has been reported previously in 154 consecutive prostatic cancer patients at our center. In 37 of these patients post-cryosurgery biopsies of the prostate were obtained. In the present report we compare this tissue to the preoperative biopsies. The data suggest that well differentiated cancers are associated with advantageous survival in cryosurgery patients. Lymphoid and eosinophilic cell infiltrates may represent post-cryosurgical local immune responses, with improved survival. Estrogen therapy seems to suppress this local immune response. One month or more after cryosurgery cancer in the biopsy correlates with palpable local recurrence but prior to 1 month it does not correlate. Cryosurgery by the open perineal approach has been an effective method to eliminate the primary lesion in localized and extensive prostatic cancer.

The cryobiological basis for cryosurgery

This paper discusses two important biological factors contributing to the death of cells within any region that is frozen cryosurgically. The first factor is the relationship between cell death and the thermal history experienced by each cell. Freezing with a single probe as usually done cannot provide sufficiently uniform conditions of cooling and warming to ensure widespread cell death. This situation can be improved by cycling a single probe at subzero temperatures or by the use of a multiple probe. The second factor is that of possible immunological responses induced by cryosurgical freezing. Improvements in understanding of biological implications of low temperatures in cryosurgery will aid the practical usefulness of these techniques.

Immune evaluation with skin testing. A study of testicular, prostatic, and bladder neoplasms

Fifty patients with testicular carcinoma, 45 with prostatic neoplasm, 84 with bladder carcinoma, and 13 with benign bladder papilloma were evaluated for skin reactivity to DNCB and other intradermal antigens. Correlation between pathologic staging and skin-test reactivity was sought. Reaction to DNCB among patients with testis tumors was more significantly depressed by chemotherapy than by the extent of retroperitoneal or distant metastatic disease indicating that skin testing as a means of following the course of disease or of predicting survival may be limited by alterations caused by chemotherapy. DNCB reactivity did not correlate with the prognosis for the different stages of disease, but follow-up studies of individual patient survival are needed for substantiation. Depression of DNCB reactivity exists among patients with prostatic carcinoma whether the disease is localized or widely metastatic. Only lengthy follow-up will determine if there is any correlation of reactivity with survival in individual patients. DNCB reactivity among patients with bladder tumors shows progressive reduction with increasing stage disease and lends support to the evidence suggesting immune deficiency in patients with bladder neoplasm.