The Nitrogen Mustards.

The nitrogen mustards are powerful cytotoxic and lymphoablative agents and have been used for more than 60 years. They are employed in the treatment of cancers, sarcomas, and hematologic malignancies. Cyclophosphamide, the most versatile of the nitrogen mustards, also has a place in stem cell transplantation and the therapy of autoimmune diseases. Adverse effects caused by the nitrogen mustards on the central nervous system, kidney, heart, bladder, and gonads remain important issues. Advances in analytical techniques have facilitated the investigation of the pharmacokinetics of the nitrogen mustards, especially the oxazaphosphorines, which are prodrugs requiring metabolic activation. Enzymes involved in the metabolism of cyclophosphamide and ifosfamide are very polymorphic, but a greater understanding of the pharmacogenomic influences on their activity has not yet translated into a personalized medicine approach. In addition to damaging DNA, the nitrogen mustards can act through other mechanisms, such as antiangiogenesis and immunomodulation. The immunomodulatory properties of cyclophosphamide are an area of current exploration. In particular, cyclophosphamide decreases the number and activity of regulatory T cells, and the interaction between cyclophosphamide and the intestinal microbiome is now recognized as an important factor. New derivatives of the nitrogen mustards continue to be assessed. Oxazaphosphorine analogs have been synthesized in attempts to both improve efficacy and reduce toxicity, with varying degrees of success. Combinations of the nitrogen mustards with monoclonal antibodies and small-molecule targeted agents are being evaluated. SIGNIFICANCE STATEMENT: The nitrogen mustards are important, well-established therapeutic agents that are used to treat a variety of diseases. Their role is continuing to evolve.

Liquid nitrogen spray cryotherapy for eradication of dysplastic Barrett's esophagus: results from a multicenter prospective registry.

BACKGROUND AND AIMS: Liquid nitrogen spray cryotherapy (SCT) is an alternative to radiofrequency ablation (RFA) for eradication of dysplastic Barrett's esophagus (BE). We aimed to assess the safety, efficacy, and durability of SCT in a multicenter U.S. registry. METHODS: This is a multicenter prospective registry of adults with BE treated with truFreeze Spray Cryotherapy (Steris, Mentor, Ohio, USA) (4 community and 11 academic sites, 2013-2022). Complete eradication of intestinal metaplasia (CEIM) and dysplasia (CED) were assessed in BE with dysplasia or intramucosal adenocarcinoma. Kaplan-Meier analysis of CEIM and CED was performed. Hazard ratios for CEIM stratified by baseline risk factors were calculated. RESULTS: Among 138 subjects with low-grade dysplasia (24%), high-grade dysplasia (49%), and intramucosal adenocarcinoma (27%), 34% received prior RFA therapy. Subjects received a median of 2 SCT sessions. Adverse events were uncommon, with 5.5% reporting strictures and 0.7% a perforation. Rates of CEIM and CED, respectively, were 66% and 84% after 2 years and 67% and 92% after 3 years. In RFA-naïve patients, CEIM was 77% and CED was 96% at 3 years. Increasing BE length (per centimeter: adjusted hazard ratio, 0.90; 95% confidence interval, 0.83-0.96) and prior treatment with RFA (adjusted hazard ratio, 0.39; 95% confidence interval, 0.22-0.69) were associated with a lower rate of CEIM. Recurrence occurred in 8.8% (n = 6) at a mean follow-up of 2.5 years after CEIM. CONCLUSION: In this largest reported prospective cohort, liquid nitrogen SCT was safe and effective for the treatment of dysplastic and neoplastic BE. Response was lower in those with prior failed RFA; in that cohort, approximately 50% attained CEIM at 3 years.

Skin thermal recovery following cryotherapy: a comparison of liquid nitrogen and liquid nitrous oxide.

Cryotherapy is a common technique used in the management of superficial skin lesions, with current advice on the correct timing for freeze-thaw cycles based on nonscientific visual skin appearances. We investigated the effect of cryotherapy on thermal thawing times by creating a porcine skin model in a laboratory setting maintained at normal skin temperature and comparing liquid nitrogen and liquid nitrous oxide. Thermal assessment was performed using a thermal camera attached to an iPhone 11Pro® smartphone. Liquid nitrogen reduced skin temperature to -60 °C after 5 s of application, recovering to 0 °C after 70 s. Liquid nitrous oxide reduced skin temperature to -34.8 °C after 5 s but had a faster recovery to 0 °C after only 20 s. Both cryogens required a thawing period of 5 min to recover to normal skin temperature. We therefore suggest that optimum cellular degradation should allow for 5-min freeze-thaw cryotherapy cycles; a slower thawing period than is in current common practice.

Combinatorial approaches of nanotherapeutics for inflammatory pathway targeted therapy of prostate cancer.

Prostate cancer (PC) is the most prevalent male urogenital cancer worldwide. PC patients presenting an advanced or metastatic cancer succumb to the disease, even after therapeutic interventions including radiotherapy, surgery, androgen deprivation therapy (ADT), and chemotherapy. One of the hallmarks of PC is evading immune surveillance and chronic inflammation, which is a major challenge towards designing effective therapeutic formulations against PC. Chronic inflammation in PC is often characterized by tumor microenvironment alterations, epithelial-mesenchymal transition and extracellular matrix modifications. The inflammatory events are modulated by reactive nitrogen and oxygen species, inflammatory cytokines and chemokines. Major signaling pathways in PC includes androgen receptor, PI3K and NF-κB pathways and targeting these inter-linked pathways poses a major therapeutic challenge. Notably, many conventional treatments are clinically unsuccessful, due to lack of targetability and poor bioavailability of the therapeutics, untoward toxicity and multidrug resistance. The past decade witnessed an advancement of nanotechnology as an excellent therapeutic paradigm for PC therapy. Modern nanovectorization strategies such as stimuli-responsive and active PC targeting carriers offer controlled release patterns and superior anti-cancer effects. The current review initially describes the classification, inflammatory triggers and major inflammatory pathways of PC, various PC treatment strategies and their limitations. Subsequently, recent advancement in combinatorial nanotherapeutic approaches, which target PC inflammatory pathways, and the mechanism of action are discussed. Besides, the current clinical status and prospects of PC homing nanovectorization, and major challenges to be addressed towards the advancement PC therapy are also addressed.

Outcomes of Radiofrequency Ablation Compared to Liquid Nitrogen Spray Cryotherapy for the Eradication of Dysplasia in Barrett's Esophagus.

INTRODUCTION: Current guidelines recommend endoscopic eradication therapy (EET) for Barrett's esophagus (BE) with dysplasia and intramucosal adenocarcinoma using either radiofrequency ablation (RFA) or liquid nitrogen spray cryotherapy (LNSC). The aims of this multicenter study are to compare the rate and number of treatment sessions of RFA vs. LNSC to achieve CE-D and CE-IM and assess outcomes for those who switched therapy. METHODS: This is a retrospective cohort study of patients with BE undergoing EET. Demographics, baseline variables, endoscopy details, and histology information were abstracted. RESULTS: One hundred and sixty-two patients were included in this study with 100 patients in the RFA group and 62 patients in the LNSC group. The rate of CE-D and CE-IM did not differ between the RFA group and LNSC group (81% vs. 71.0%, p = 0.14) and (64% vs. 66%, p = 0.78), respectively. The number of sessions to achieve CE-D and CE-IM was higher with LNSC compared to RFA (4.2 vs. 3.2, p = 0.05) and (4.8 vs. 3.5, p = 0.04), respectively. The likelihood of developing recurrent dysplasia was higher among patients who did not achieve CE-IM (12%) compared to those who did achieve CE-IM (4%), p = 0.04. Similar findings were found in those who switched treatment modalities. DISCUSSION: EET is highly effective in eradication of Barrett's associated dysplasia and neoplasia. Both RFA and LNSC achieved similar rates of CE-D and CE-IM although LNSC required more sessions. Also, achievement of CE-IM was associated with less recurrence rates of dysplasia.

Efficacy and Safety of Liquid Nitrogen Cryotherapy for Lichen Simplex Chronicus: A Meta-Analysis.

BACKGROUND: Lichen simplex chronicus (LSC) is characterized by localized lichenification and intense itching. It has been reported that the added use of liquid nitrogen cryotherapy (LNC) for LSC has significant efficacy and notable safety. Therefore, we conducted a meta-analysis based on existing randomized controlled trials (RCTs). METHOD: We searched RCTs on LNC for LSC published up to August 2020 using various databases, including PubMed, EMBASE, Web of Science, Cochrane Central Register of Controlled Trials, China Network Knowledge Infrastructure (CNKI), Chinese Biomedicine (CBM), Chinese Scientific Journals Database (VIP), and WanFang Database. Other studies were manually identified using the references cited in reviews. We applied fixed- or random-effects models, and all analyses were performed using Review Manager 5.4 software. RESULTS: Twelve RCTs involving 1,066 participants provided eligible data for the meta-analysis. Based on the clinical effective rate, LNC treatment of LSC (risk ratio, RR 1.25, p = 0.005, I2 = 82%) was superior to controls. Subgroup analysis showed that the use of LNC alone (RR 1.04, I2 = 95%, p > 0.05) is not more effective than other therapies in the treatment of LSC, but the addition of LNC to the existing treatment increases the total clinical efficacy. Furthermore, the combined effect of LNC and topical medication (RR 1.39, I2 = 0%, p < 0.0001) was better than that of LNC and oral medication (RR 1.30, I2 = 0%, p < 0.00001). Greater frequency of LNC treatment did not improve the efficacy (thrice a week: RR 1.39 [1.21, 1.60]; twice a week: RR 1.27; once every 2 weeks: RR 1.32). Data from 6 RCTs with 508 participants showed no significant difference in AEs (p = 0.31) associated with added LNC treatment. CONCLUSION: The addition of LNC (applying a cotton swab soaked with liquid nitrogen to wipe the lesion for approximately 10 s each time) to topical ointments, is effective and safe in the treatment of LSC. Increasing the treatment frequency of LNC did not necessarily improve the efficacy.

Ascorbic acid and hydrocortisone synergistically inhibit septic organ injury via improving oxidative stress and inhibiting inflammation.

BACKGROUND: The current study aimed to investigate the effect of the combination of ascorbic acid (AscA) and hydrocortisone (Hyd) on septic organ injury and its potential mechanism. METHOD: Sepsis was induced in mice by a single intraperitoneal injection of lipopolysaccharides. RESULTS: AscA and Hyd combined showed more effective protection of the injured liver and kidney in septic mice by decreasing alanine aminotransferase, aspartate aminotransferase, serum urea nitrogen, and serum creatinine and ameliorating pathological manifestations than Hyd or AscA alone. AscA showed a mild inhibitory effect on the secretion of proinflammatory cytokines (tumor necrosis factor-alpha (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6)). However, Hyd showed a weak regulatory effect on septic oxidative stress markers (malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px)). However, the combination of AscA and Hyd showed a more powerful inhibitory effect on the septic inflammatory response and oxidative stress than Hyd or AscA alone by decreasing TNF-α, IL-1ß, and IL-6 and regulating MDA, SOD, and GSH. In an in vitro study, cotreatment of RAW 264.7 macrophages with Hyd and AscA sharply reduced reactive oxygen species (ROS) generation and synergistically inhibited TNF-α, IL-1ß, and IL-6 secretion, which could be abolished by additional stimulation with the ROS donor 3-nitropropionic acid (3-NP). As expected, cotreatment of macrophages with Hyd and AscA synergistically inhibited the activation of p38 MAPK and p-p65, and the effect could be reversed by additional stimulation with 3-NP. CONCLUSIONS: AscA and Hyd synergistically protect the kidney and liver from injury by inhibiting the inflammatory response and oxidative stress. The powerful inhibitory effects of AscA on oxidative stress contribute to the synergistic anti-inflammatory action.

Reconstruction using a frozen autograft for a skull and humeral lesion of synchronous multicentric osteosarcoma after undergoing successful neoadjuvant chemotherapy: a case report and review of the literature.

BACKGROUND: Synchronous multicentric osteosarcoma (SMOS) is a rare disease characterized by simultaneous multicentricity of intraosseous osteosarcoma without visceral involvement. SMOS, including a skull lesion, which occurs relatively rarely, and reconstruction using a frozen autograft after the excision of a lesion of SMOS has been infrequently reported previously. CASE PRESENTATION: We report an 18-year-old girl with SMOS, with lesions located in the left distal femur, right proximal humerus, and left occipital bone. Her major complaint was pain and swelling around the left knee joint. Asymptomatic lesions of the humerus and skull bone were detected on a systemic bone scan. No visceral organ metastasis was observed. A biopsy of the distal femoral lesion revealed osteosarcoma. Based on the histological findings, multiple bone lesions, and absence of visceral lesion, the clinical diagnosis of SMOS was made. After five courses of neoadjuvant chemotherapy with a regimen of doxorubicin and cisplatin, reconstruction using a tumor prosthesis following wide excision of the left distal femur was performed, and total necrosis was histologically observed in the retracted specimen. Following three cycles of adjuvant chemotherapy, tumor excision and reconstruction with a frozen autograft treated with liquid nitrogen was conducted for both lesions of the humerus and skull, rather than tumor prosthesis or synthetics, in order to retain a normal shoulder function, and to obtain a good cosmetic and functional outcome after treatment of the skull lesion. Further adjuvant chemotherapy could not be administered after the completion of the surgical treatment for all lesions because the adverse events due to chemotherapy were observed. At over 5 years after the diagnosis, she remains clinically disease-free. CONCLUSIONS: An early correct diagnosis, the proper management of chemotherapy, and surgical treatment for all lesions are essential for achieving a good clinical outcome, even in SMOS including a skull lesion. By performing reconstruction using a frozen autograft for a proximal humeral lesion and a skull lesion after confirming the good histological efficacy of neoadjuvant chemotherapy for the primary lesion, the excellent function of the shoulder joint and a good cosmetic outcome at the site of the skull lesion was acquired without complications or recurrence.

Helium Plasma Skin Regeneration: Evaluation of Skin Tissue Effects in a Porcine Model and Comparison to Nitrogen Plasma Skin Regeneration.

BACKGROUND AND OBJECTIVES: Helium plasma skin regeneration (PSR) is a novel skin rejuvenation technology with significant differences compared with nitrogen PSR technology but that may exert similar skin tissue effects. Study objectives included a comparison of acute and chronic skin tissue changes among the two plasmas in a porcine animal model. STUDY DESIGN/MATERIALS AND METHODS: In this study, both helium and nitrogen gas plasmas were used to treat the dorsal skin of Yorkshire cross mini pigs with 20% (8.6 J/cm2 ) and 40% (17.8 J/cm2 ) power helium plasma single pass treatment (4 liter gas flow, continuous energy delivery, and linear non-overlapping passes) compared with high energy nitrogen plasma double pass treatment (PSR3 @ 14.1 J/cm2 : 4.0 J, 2.5 Hz pulse rate, overlapping horizontal, and vertical passes). Acute and chronic skin contraction, maximum acute depth of injury and chronic reparative healing depth were assessed along with representative histopathology in each treatment paradigm. RESULTS: High-energy nitrogen plasma treatment exhibited greatest mean depth of acute tissue injury 4 hours post-treatment whereas helium plasma treatment exhibited greater acute skin tissue contraction. Then, 20% and 40% power helium plasma treatment results were each very similar among animals as a percentage of nitrogen plasma treatment results for both depths of acute tissue injury and acute skin tissue contraction. Mean depths of reparative tissue healing were similar among treatment paradigms 30 days after treatment with significant intra- and inter-animal variability observed within each treatment paradigm. Thirty-day mean skin tissue contraction was greater for helium plasma treatment; however, the data varied significantly between animals in all paradigms. Histopathologic tissue evaluation after 30 days showed similar findings among the treatment paradigms with epidermal hyperplasia, flattening of rete ridges and with regenerative granulation tissue expanding the superficial and papillary dermis. CONCLUSIONS: This study demonstrates modestly reduced depth of the thermal effect, greater skin tissue contraction and similarity of acute and chronic histopathological findings for helium plasma when compared with nitrogen plasma in a porcine animal model. © 2019 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals, Inc.

Liquid nitrogen spray cryotherapy-based multimodal endoscopic management of dysplastic Barrett's esophagus and early esophageal neoplasia: retrospective review and long-term follow-up at an academic tertiary care referral center.

BACKGROUND: Endoscopic eradication therapy of dysplastic Barrett's esophagus (BE) and early esophageal neoplasia has emerged as an effective treatment option. Data for the role of spray cryotherapy (SCT) in this setting is relatively limited. OBJECTIVE: To evaluate the safety and long-term outcomes of SCT-based multimodal therapy in the management of dysplastic BE and early esophageal neoplasia. DESIGN: Single-center, retrospective, cohort study. SETTING: Academic, tertiary care center between August 2008 and February 2019. METHODS: A retrospective chart review was conducted of the prospectively maintained endoscopic cryotherapy database at our center. Fifty-seven patients were identified who underwent SCT treatment for dysplastic BE and esophageal or Gastro-esophageal (GE) junction adenocarcinoma during the study period. Primary outcome was complete eradication of intestinal metaplasia (CE-IM); secondary outcome was complete eradication of dysplasia (CE-D). RESULTS: A total of 171 SCT procedures were performed in 57 patients. The majority of patients were male (89.5%) with long-segment BE (93%; mean segment length 6.2 cm). Complete follow-up data was available for 56 of these 57 patients. 43.9% (25/57) of patients underwent radiofrequency ablation (RFA) during the course of treatment (e.g. after initiating SCT). 33.3% of patients (19/57) were RFA failures prior to SCT. Additionally, 68.4% (39/57) of patients underwent endoscopic resection (EMR) prior to SCT as part of our multimodal approach to treatment of BE dysplasia/neoplasia. Four patients (7%) are currently undergoing active ablation and/or EMR treatment. CE-IM was achieved in 75% (39/52) of patients, and CE-D in 98.1% (51/52). Mean duration of overall follow-up was 4.8 years, with mean CE-IM durability of 2.6 years. LIMITATIONS: Single-center only, retrospective study design. CONCLUSION: SCT-based multimodal endoscopic therapy can achieve very high CE-IM (75%) and CE-D (>98%) rates in a high-risk population with esophageal dysplasia and/or neoplasia.

Cryotherapy to treat benign skin tumours in conscious dogs.

BACKGROUND: Cryotherapy can be used to treat benign skin lesions without general anaesthesia. This technique has only been described in anaesthetized dogs. OBJECTIVE: To describe the feasibility, safety and efficacy of cryotherapy to treat benign skin tumours in conscious dogs. ANIMALS: Twenty-five client-owned dogs with 52 skin tumours diagnosed as benign sebaceous neoplasia (46) or follicular cysts (six). METHODS AND MATERIALS: Cryotherapy was performed in conscious dogs using a liquid nitrogen spray technique with a handheld spray-release system. If needed, cryotherapy was repeated every three to four weeks until complete cure was achieved or for a maximum of eight treatments. Effectiveness and adverse effects were recorded. RESULTS: Resolution was obtained for 29 of 52 lesions (57%) with a median number of one to two cryotherapy sessions. Eighteen of 52 (35%) lesions shrank to <0.1 cm. In one case, the tumour enlarged after cryotherapy, and histopathological examination of the excisional biopsy revealed an apocrine gland carcinoma. Pain and discomfort during the treatment were the most common adverse effects (33%). CONCLUSIONS AND CLINICAL IMPORTANCE: In the present study, cryotherapy was possible in conscious dogs and proved to be effective to cure or reduce the size of benign sebaceous tumours and follicular cysts. The procedure is safe but the degree of pain during the treatment needs to be further investigated. Worsening of the lesion after cryotherapy suggests the need for surgical removal and histopathological examination.

Influence of oxygen enriched gases during decompression on bubble formation and endothelial function in self-contained underwater breathing apparatus diving: a randomized controlled study.

AIM: To assess the effect of air, gas mixture composed of 50% nitrogen and 50% oxygen (nitrox 50), or gas mixture composed of 1% nitrogen and 99% oxygen (nitrox 99) on bubble formation and vascular/endothelial function during decompression after self-contained underwater breathing apparatus diving. METHODS: This randomized controlled study, conducted in 2014, involved ten divers. Each diver performed three dives in a randomized protocol using three gases: air, nitrox 50, or nitrox 99 during ascent. The dives were performed on three different days limited to 45 m sea water (msw) depth with 20 min bottom time. Nitrogen bubbles formation was assessed by ultrasound detection after dive. Arterial/endothelial function was evaluated by brachial artery flow mediated dilatation (FMD) before and after dive. RESULTS: Nitrox 99 significantly reduced bubble formation after cough compared with air and nitrox 50 (grade 1 vs 3 and vs 3, respectively, P=0.026). Nitrox 50 significantly decreased post-dive FMD compared with pre-dive FMD (3.62 ± 5.57% vs 12.11 ± 6.82% P=0.010), while nitrox 99 did not cause any significant change. CONCLUSION: Nitrox 99 reduced bubble formation, did not change post-dive FMD, and decreased total dive duration, indicating that it might better preserve endothelial function compared with air and nitrox 50 dive protocols.

Efficacy of liquid nitrogen cryotherapy for Barrett's esophagus after endoscopic resection of intramucosal cancer: A multicenter study.

BACKGROUND AND AIM: Liquid nitrogen cryotherapy (LNC) allows increased depth of ablation compared with radiofrequency ablation in Barrett's esophagus (BE). Expert centers may use LNC over radiofrequency ablation to ablate Barrett's esophagus after endoscopic resection of intramucosal cancer (IMCA). The aim of our study was to (1) evaluate the safety and efficacy of LNC ablation in patients with BE and IMCA and (2) to evaluate the progression to invasive disease despite therapy. METHODS: This was a multicenter, retrospective study of consecutive patients with BE who received LNC following endoscopic mucosal resection (EMR) of IMCA. The outcomes evaluated were complete eradication of dysplasia and intestinal metaplasia and development of invasive cancer during follow up. The follow-up period was at least 1 year from initial LNC. RESULTS: Twenty-seven patients were identified. The median Prague score was C3M5 (range C0M1-C14M14). After EMR+LNC, the median Prague score was C0M1 (range C0M0-C9M10); 22/27 patients (82%) achieved complete eradication of dysplasia after cryotherapy, and 19/27 patients (70%) achieved complete eradication of intestinal metaplasia. One out of 27 patients (4%) developed invasive cancer (disease beyond IMCA) over the study period. CONCLUSION: Cryotherapy is an effective endoscopic tool for eradication of BE dysplasia after EMR for IMCA. Development of invasive cancer is low for this high-risk group.

Cryotherapy of cutaneous leishmaniasis caused by Leishmania major in BALB/c mice: A comparative experimental study.

BACKGROUND & OBJECTIVES: Leishmania parasites are sensitive to very low temperature. Cryotherapy is considered as an alternative to the existing pentavalent antimonials, for local treatment of cutaneous leishmaniasis (CL). Normally, liquid nitrogen (N2) at a temperature of -196 °C, is used in cryotherapy of CL, but it's efficacy is not consistent. Recently, few studies have also reported the use of carbon dioxide (CO2) slush at -78.5 °C in CL cryotherapy. This study was aimed to evaluate the effectiveness of N2 vs CO2 cryotherapy for CL treatment in mice. Methods: In total, 21 BALB/c mice were infected with Leishmania major strain [MRHO/IR/74/ER]. Samples were divided into three groups based on the intervention provided-Solid CO2 cryotherapy, liquid N2 cryotherapy and control group; with seven mice randomly assigned to each group. Control group received no intervention, and in the other two groups cryotherapy was used every two weeks for maximum of three months. Follow up examinations were scheduled at the time of cryotherapy, during which the size of each lesion was measured. For three mice in each study group, the spleen parasite DNA load was quantified using real-time PCR. RESULTS: After treatment, the liquid N2 cryotherapy showed significant reduction in size of the lesions (p = 0.029) as compared to the solid CO2 cryotherapy and control group. Also, Leishmania DNA load in spleen was significantly lower in the mice receiving liquid N2 cryotherapy (p <0.001). INTERPRETATION & CONCLUSION: Liquid N2 cryotherapy is superior to CO2 cryotherapy, and it can be an effective method for controlling L. major infection. Further investigations are essential to find optimal number of treatment sessions and time intervals.

Cryoablation in the management of Barrett's esophagus.

PURPOSE OF REVIEW: Providing an overview on types of cryotherapy for esophageal application and their role in the management of Barrett's esophagus. RECENT FINDINGS: Recent studies have involved multiple types of cryotherapy including cryospray techniques that use either liquid nitrogen or carbon dioxide as the cryogenic fluid, and the CryoBalloon focal ablation device that uses nitrous oxide. Overall, studies report cryotherapy to be safe and effective in eradicating Barrett's epithelium. However, substantial variations among these studies in design and outcomes preclude direct comparisons of the results. Moreover, little is known of the long-term outcomes of cryotherapy, with only one report describing 5-year follow-up of patients treated with liquid nitrogen cryospray. SUMMARY: The concept of cryotherapy is appealing. By preserving the extracellular matrix and inducing anesthetic effects, cryotherapy has the potential to enable deeper ablations with less pain and a lower rate of stricture formation than radiofrequency ablation. To date, however, these potential benefits remain unproved. Prospective studies with clearly defined endpoints and longer follow-up are necessary to determine the role of cryotherapy in the management of patients with Barrett's esophagus.

Outcomes after liquid nitrogen spray cryotherapy in Barrett's esophagus-associated high-grade dysplasia and intramucosal adenocarcinoma: 5-year follow-up.

BACKGROUND AND AIMS: Liquid nitrogen spray cryotherapy (LNSCT) has been shown to be a safe, well-tolerated, and effective therapy for Barrett's esophagus (BE)-associated high-grade dysplasia (BE-HGD) and intramucosal adenocarcinoma (IMC). Long-term follow-up is lacking. AIMS: The aim of this study was to assess the efficacy, durability, and rate of neoplastic progression after LNSCT in BE-HGD/IMC at 3 and 5 years. METHODS: In this single-center, retrospective study drawn from a prospective database, patients with BE-HGD/IMC of any length treated with LNSCT were followed with surveillance endoscopy with biopsy for 3 to 5 years. Patients with IMC completely removed by endoscopic resection were included. Outcome measures included complete eradication of HGD (CE-HGD), dysplasia, and intestinal metaplasia; incidence rates; durability of response; location of recurrent intestinal metaplasia and dysplasia; and rate of disease progression. RESULTS: A total of 50 and 40 patients were included in 3-year and 5-year analyses. Initial CE-HGD, dysplasia, and intestinal metaplasia achieved in 98%, 90%, and 60%, respectively. Overall CE-HGD, dysplasia, and intestinal metaplasia at 3 years were 96% (48/50), 94% (47/50), and 82% (41/50), and at 5 years were 93% (37/40), 88% (35/40), and 75% (30/40). Incidence rates of recurrent intestinal metaplasia, dysplasia, and HGD/esophageal adenocarcinoma per person-year of follow-up after initial complete eradication of intestinal metaplasia (CE-IM) were 12.2%, 4.0%, and 1.4% per person-year for the 5-year cohort. Most recurrences were found immediately below the neosquamocolumnar junction. Two of 7 HGD recurrences occurred later than 4 years after initial eradication, and 2 patients (4%) progressed to adenocarcinoma despite treatment. CONCLUSIONS: In patients with BE-HGD/IMC, LNSCT is effective in eliminating dysplasia and intestinal metaplasia. Progression to adenocarcinoma was uncommon, and recurrence of dysplasia was successfully treated in most cases. Long-term surveillance is necessary to detect late recurrence of dysplasia.

Freezing Nitrogen Ethanol Composite May be a Viable Approach for Cryotherapy of Human Giant Cell Tumor of Bone.

BACKGROUND: Liquid nitrogen has been used as adjuvant cryotherapy for treating giant cell tumor (GCT) of bone. However, the liquid phase and ultrafreezing (-196° C) properties increase the risk of damage to the adjacent tissues and may lead to perioperative complications. A novel semisolid cryogen, freezing nitrogen ethanol composite, might mitigate these shortcomings because of less-extreme freezing. We therefore wished to evaluate freezing nitrogen ethanol composite as a coolant to determine its properties in tumor cryoablation. QUESTIONS/PURPOSES: (1) Is freezing nitrogen ethanol composite-mediated freezing effective for tumor cryoablation in an ex vivo model, and if yes, is apoptosis involved in the tumor-killing mechanism? (2) Does freezing nitrogen ethanol composite treatment block neovascularization and neoplastic progression of the grafted GCTs and is it comparable to that of liquid nitrogen in an in vivo chicken model? (3) Can use of freezing nitrogen ethanol composite as an adjuvant to curettage result in successful short-term treatment, defined as absence of GCT recurrence at a minimum of 1 year in a small proof-of-concept clinical series? METHODS: The cryogenic effect on bone tissue mediated by freezing nitrogen ethanol composite and liquid nitrogen was verified by thermal measurement in a time-course manner. Cryoablation on human GCT tissue was examined ex vivo for effect on morphologic features (cell shrinkage) and DNA fragmentation (apoptosis). The presumed mechanism was investigated by molecular analysis of apoptosis regulatory proteins including caspases 3, 8, and 9 and Bax/Bcl-2. Chicken chorioallantoic membrane was used as an in vivo model to evaluate the effects of freezing nitrogen ethanol composite and liquid nitrogen treatment on GCT-derived neovascularization and tumor neoplasm. A small group of patients with GCT of bone was treated by curettage and adjuvant freezing nitrogen ethanol composite cryotherapy in a proof-of-concept study. Tumor recurrence and perioperative complications were evaluated at a minimum of 19 months followup (mean, 24 months; range, 19-30 months). RESULTS: Freshly prepared freezing nitrogen ethanol composite froze to -136° C and achieved -122° C isotherm across a piece of 10 ± 0.50-mm-thick bone with a freezing rate of -34° C per minute, a temperature expected to meet clinical tumor-killing requirements. Human GCT tissues revealed histologic changes including shrinkage in morphologic features of multinucleated giant cells in the liquid nitrogen (202 ± 45 µm; p = 0.006) and freezing nitrogen ethanol composite groups (169 ± 27.4 µm; p < 0.001), and a decreased nucleated area of neoplastic stromal cells for the 30-second treatment. Enhanced counts of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells verified the involvement of DNA fragmentation in cryoablated GCT tissues. Western blotting analysis on the expression of apoptosis regulatory proteins showed enhancement of proteocleavage-activated caspases 3, 8, and 9 and higher ratios of Bax/Bcl2 in the liquid nitrogen- and freezing nitrogen ethanol composite-treated samples. Numbers of blood vessels and human origin tumor cells also were decreased by freezing nitrogen ethanol composite and liquid nitrogen treatment in the GCT-grafted chicken chorioallantoic membrane model. Seven patients with GCT treated by curettage and adjuvant cryotherapy by use of freezing nitrogen ethanol composite preparation had no intra- or postoperative complications related to the freezing, and no recurrences during the study surveillance period. CONCLUSIONS: These preliminary in vitro and clinical findings suggest that freezing nitrogen ethanol composite may be an effective cryogen showing ex vivo and in vivo tumor cryoablation comparable to liquid nitrogen. The semisolid phase and proper thermal conduction might avoid some of the disadvantages of liquid nitrogen in cryotherapy, but a larger clinical study is needed to confirm these findings. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Cellulitis Secondary to Liquid Nitrogen Cryotherapy: Case Report and Literature Review.

BACKGROUND: Liquid nitrogen cryotherapy is a commonly used technique to treat a wide variety of dermatologic conditions including actinic keratoses, non-melanoma skin cancers, verrucae, and seborrheic keratoses. The risks associated with liquid nitrogen cryotherapy are important to know and discuss with patients prior to treatment. OBJECTIVE: We report a case of cellulitis secondary to liquid nitrogen cryotherapy for actinic keratosis. We sought to review the literature for an estimate of secondary infection rates following cryotherapy treatment. METHODS: We searched Pubmed using the terms cryotherapy and infection or cellulitis. We then looked at articles classified as clinical trials where cryotherapy was used to treat skin conditions. We then selected clinical trials that listed cellulitis or infection as an adverse event. RESULTS AND CONCLUSION: There were no case reports, case series, or review articles detailing the risk of infection from liquid nitrogen cryotherapy. We found 8 articles classified as clinical trials on Pubmed that did list infection as an adverse event. The risk of infection from these studies varied from approximately 2% to 30%. There was a great degree of heterogeneity in treatment sites, length of treatment, and treatment targets. While it is difficult to determine the true incidence of infection from liquid nitrogen cryotherapy, clinicians should endeavor to inform patients of this potential risk.

The cryoablation of lung tissue using liquid nitrogen in gel and in the ex vivo pig lung.

PURPOSES: To examine the efficiency of cryoablation using liquid nitrogen in lung tissue, we measured the size and temperature distribution of the frozen area (iceball) in gel and in the ex vivo pig lungs. METHODS: Cryoprobes with diameters of 2.4 and 3.4 mm (2.4D and 3.4D, respectively) were used. Three temperature sensors were positioned at the surface of the cryoprobe and at distances of 0.5 and 1.5 cm from the cryoprobe. The ex vivo pig lungs were perfused with 37 °C saline and inflated using ventilator to simulate in vivo lung conditions. RESULTS: In gel, the 2.4D and 3.4D probes made iceballs of 3.9 ± 0.1 and 4.8 ± 0.3 cm in diameter, respectively, and the temperature at 1.5 cm from those probes reached -32 ± 8 and -53 ± 5 °C, respectively. In the pig lung, the 2.4D and 3.4D probes made iceballs of 5.2 ± 0.1 and 5.5 ± 0.4 cm in diameter, respectively, and the temperature at 1.5 cm from these probes reached -49 ± 5 and -58 ± 3 °C, respectively. CONCLUSION: Liquid nitrogen cryoablation using both 2.4D and 3.4D probes made iceballs that were of sufficient size, and effective temperatures were reached in both gel and the ex vivo pig lung.