Oncological and Functional Outcomes of Patients Undergoing Individualized Partial Gland Cryoablation of the Prostate: A Single-Institution Experience

Objectives: We aim at reporting the functional and oncological outcomes in men with localized prostate cancer who underwent individualized partial gland cryoablation of the prostate by using validated quality-of-life instruments. Methods: We retrospectively reviewed our cryosurgery database between July 2003 and September 2019 for men who were treated with individualized partial gland cryoablation of the prostate at our tertiary care center. Baseline and periodic urinary and sexual function surveys were administered throughout the post-treatment period. Results: A total of 82 men were included in the study. Median follow-up was 28 months (interquartile range: 10.5-59.3 months). A total of 71 men underwent primary individualized partial gland cryoablation, whereas 11 men underwent salvage partial gland ablation. Failure-free survival at 1 to 5 years was 98%, 89%, 84%, 75%, and 75% in the primary therapy group, and 100%, 80%, and 40% in the salvage group at 1 to 3 years, respectively. In the primary therapy group, all 71 patients remained free of pads at 3 months and throughout the follow-up period. Men who had undergone primary focal cryoablation had a higher post-treatment International Index of Erectile Function (IIEF) score, followed by men treated with primary hemi-cryoablation and primary subtotal cryoablation. The American Urological Association (AUA) symptom scores decreased regardless of the type of partial gland ablation performed, with subtotal ablation having the lowest score compared with hemiablation and focal cryoablation. No patient developed a fistula in the primary group, and 1 (9%) patient developed a fistula in the salvage group. Conclusion: Individualized partial gland cryoablation of the prostate is able to achieve excellent oncological and functional outcomes in select men with localized prostate cancer.

Impact of pre-ablation weight loss on the success of catheter ablation for atrial fibrillation

INTRODUCTION

Obesity is an established risk factor for recurrent atrial fibrillation (AF) after ablation. The impact of pre-procedure weight changes on freedom from AF (FFAF) after ablation in obese and nonobese patients is unknown.

METHODS

A single-center retrospective cohort study of patients undergoing pulmonary vein isolation was performed. Before ablation, all candidates were encouraged to adopt healthy lifestyle habits according to American Heart Association guidelines, including weight loss, by their physician. The primary endpoint was FFAF through 1-year after completion of the 3-month blanking period.

RESULTS

Of the 601 patients (68% male; average age 62.1 ± 10.3 years) included in analysis, 234 patients (38.9%) were obese (body mass index ≥ 30) and 315 (52.4%) had paroxysmal AF. FFAF was observed in 420 patients (69.9%) at 15 months. Percent change in weight that occurred during the year before ablation independently predicted FFAF through 15-months in all patients (adjusted odds ratio =  1.17, 95% confidence interval: 1.11-1.23). Subgroup analyses based on paroxysmal vs persistent AF, presence of obesity, and history of prior ablation were performed. Percent change in weight over the year before ablation was independently associated with FFAF in all subgroups except nonobese patients with persistent AF.

CONCLUSION

Pre-ablation weight loss was associated with FFAF in both obese and nonobese patients. Further studies are needed to define the optimal approach to weight loss before AF ablation.

Minimally invasive image-guided therapy of primary and metastatic pancreatic cancer

Pancreatic cancer is a challenging malignancy with limited treatment options and poor life expectancy. The only curative option is surgical resection, but only 15%-20% of patients are resectable at presentation because more than 50% of patients has distant metastasis at diagnosis and the rest of them has locally advanced pancreatic cancer (LAPC). The standard of care first line treatment for LAPC patients is chemotherapy with or without radiation therapy. Recent developments in minimally invasive ablative techniques may add to the treatment armamentarium of LAPC. There are increasing number of studies evaluating these novel ablative techniques, including radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation. Most studies which included pancreatic tumor ablation, demonstrated improved overall survival in LAPC patients. However, the exact protocols are yet to set up to which stage of the treatment algorithm ablative techniques can be added and in what kind of treatment combinations. Patients with metastatic pancreatic cancer has dismal prognosis with 5-year survival is only 3%. The most common metastatic site is the liver as 90% of pancreatic cancer patients develop liver metastasis. Chemotherapy is the primary treatment option for patients with metastatic pancreatic cancer. However, when the tumor is not responding to chemotherapy or severe drug toxicity develops, locoregional liver-directed therapies can provide an opportunity to control intrahepatic disease progression and improve survival in selected patients. During the last decade new therapeutic options arose with the advancement of minimally invasive technologies to treat pancreatic cancer patients. These new therapies have been a topic of increasing interest due to the severe prognostic implications of locally advanced and metastatic pancreatic cancer and the low comorbid risk of these procedures. This review summarizes new ablative options for patients with LAPC and percutaneous liver-directed therapies for patients with liver-dominant metastatic disease.

Image-guided percutaneous cryoablation of T1b renal cell carcinomas in patients with comorbidities

PURPOSE

To investigate the influence of comorbidities and tumor characteristics on outcomes following percutaneous cryoablation (PCA) of T1b renal cell carcinoma (RCC).

MATERIALS AND METHODS

Age-adjusted Charlson comorbidity index (ACCI); standardized system for quantitating renal tumor size, location, and depth (RENAL nephrometry score [RNS]); and local tumor control and survival were retrospectively investigated in 28 patients who underwent PCA for stage T1b RCC. Risk factors for elevated serum creatinine levels were also investigated.

RESULTS

Complete ablation was obtained in 27 of 28 patients. Two cases of metastasis were observed; one patient died 12 months after PCA. Overall survival at 5 years was 79.1%, with a mean follow-up of 42.0 ± 16.0 months. Local tumor control was not correlated with the ACCI and RNS. Worsening renal function 3 months after PCA was observed in ten patients, and it correlated with the presence of single kidneys (7/28 patients; p = 0.023). Significant worsening of renal function continued until 1 year after PCA (p = 0.013). Having a single kidney was a risk factor for worsened renal function after PCA (odds ratio, 8.00; 95% confidence interval 1.170-54.724).

CONCLUSION

PCA for T1b RCC confers positive local tumor control regardless of comorbidities and tumor characteristics.

The suture fixation of levonorgestrel-releasing intrauterine device using the hysteroscopic cold-knife surgery system: an original method in treatment of adenomyosis

OBJECTIVE

To introduce an effective approach using the hysteroscopic cold-knife surgery system (HCSS) for suture fixation of the levonorgestrel-releasing intrauterine device (LNG-IUD) in patients with adenomyosis.

DESIGN

Video description of the surgical procedures to demonstrate the detailed technique. The study was reviewed and approved by the institutional review board of Hangzhou Women's Hospital.

SETTING

Maternity hospital.

PATIENT(S)

A 39-year-old woman diagnosed with adenomyosis had endured 7 years of severe dysmenorrhea and 4 years of heavy menstrual bleeding. She had a past medical history that was significant for expulsion of an LNG-IUD. Transvaginal ultrasonography revealed that her uterus was enlarged by adenomyosis. She insisted on preserving fertility potential.

INTERVENTION(S)

We proceeded with the HCSS and the uterine cavity was found enlarged significantly. In consideration of the patient's strong desire for maintaining fertility options, the fixation of the LNG-IUD on the intrauterine posterior wall with an Ethibond suture was performed successfully through an endoscopic needle driver and a knot-pushing device. Proficient endoscopic suturing is the key to the technique. Informed consent was obtained from the patient.

MAIN OUTCOME MEASURE(S)

Feasibility and value of using the HCSS to fix an LNG-IUD for treatment of adenomyosis.

RESULT(S)

The LNG-IUD was fixed successfully by the HCSS with an Ethibond suture on the posterior wall of the uterus within 30 minutes, and the intraoperative blood loss was 2 mL. The patient was discharged 24 hours postoperatively without any adverse perioperative complications. At the one-year follow-up, the patient reported obvious relief of her dysmenorrhea and menorrhagia and no more experience with expulsion. Ultrasound demonstrated normal position of the IUD at 1, 3, 6, and 12 months postoperatively.

CONCLUSION(S)

Hysteroscopy presents a clear visual field to locate and fix the IUD. In patients with adenomyosis suffering from dysmenorrhea or excessive menstrual blood loss, suture fixation of the LNG-IUD using the HCSS can be a minimally invasive and effective alternative for treating adenomyosis, especially in patients who have previously expelled an LNG-IUD, preventing the risk of expulsion.

Impact of Cryoballoon Ablation on Electrophysiology Lab Efficiency During the Treatment of Patients With Persistent Atrial Fibrillation: A Subanalysis of the STOP Persistent AF Study

BACKGROUND

The volume of atrial fibrillation (AF) catheter ablation procedures has increased to address the growing patient population with AF; however, the impact of cryoballoon ablation on electrophysiology (EP) lab throughput is under-studied when treating patients with persistent AF (PsAF).

OBJECTIVE

To assess EP lab utilization associated with cryoballoon ablation for the treatment of patients with PsAF and to evaluate mechanisms that optimize hospital resources.

METHODS

Procedural data derived from the STOP Persistent AF trial were input into a discrete event simulation to assess EP lab utilization during AF ablation procedures. Patient and physician delays and lab occupancy times were modeled in a nominal and efficient EP lab setting over 1000 days. Accounting for variation in procedural times, we evaluated the number of days in which preplanned pulmonary vein isolation (PVI) cases resulted in overtime or excess time for non-ablation EP cases within a given lab day. A sensitivity analysis determined the parameters that most strongly influenced EP lab throughput.

RESULTS

Lab occupancy times for the Nominal Use (NU) case included 165 procedures, and the High-Efficiency Use (HEU) case was derived from 69 procedures conducted at sites with faster procedure times than average. The HEU case had shorter lab occupancy times than the NU case (158 ± 32 minutes vs 188 ± 51 minutes, respectively). In the NU case, a total of 2000 procedures were conducted, with 28 lab days (2.8%) extending into overtime and 900 lab days (90%) exhibiting excess time for a non-ablation EP case. In the HEU case, a total of 3000 procedures were conducted, with 87 lab days (8.7%) extending into overtime and 635 lab days (63.5%) exhibiting excess time for a non-ablation EP case. The model was most sensitive to lab occupancy duration and the time of day that overtime started.

CONCLUSIONS

Cryoballoon ablation for the treatment of patients with PsAF confers EP lab efficiencies that can support 3 PVI cases in a lab day.

The role of CT and endoscopy in the evaluation of patients referred for intranasal Cryoablation

BACKGROUND

Cryoablation (CA) of the posterior nasal nerves has garnered increasing interest as an office-based procedure for chronic rhinitis (CR). Standardized preoperative evaluation, specifically the role of computed tomography (CT) and nasal endoscopy, has yet to be defined. We report a series of patients who underwent CT and endoscopy as part of CR work-up in patients referred for CA.

OBJECTIVE

Highlight the importance of both nasal endoscopy and CT scan in the evaluation of CR given significant overlap of symptoms and common occurrence of related sinonasal conditions.

METHODS

Retrospective analysis of all patients referred to a single tertiary rhinology practice for CA was performed.

RESULTS

Fifteen patients were sent for CA by medical allergists. Five patients were deemed CA candidates, and 1 patient received only medical CR treatment. Four patients had evidence of incomplete prior sinus surgery and/or continued chronic rhinosinusitis on endoscopic exam. These 4 patients received a combination of medical and surgical management with either complete resolution or improvement in CR symptoms. In 3 patients, CT confirmed chronic rhinosinusitis that was not apparent on endoscopy, and received a combination of medical and surgical management with symptom improvement. In the last two patients, final diagnoses were nasal valve collapse and recurrent acute rhinosinusitis.

CONCLUSIONS

Referrals for CA are becoming more common and the optimal preoperative work up remains unclear. In this limited retrospective review, 67% of patients had diagnoses other than CR and thus were not deemed candidates for CA. Both CT and endoscopy are complementary to a detailed history and physical examination and can aid in CA candidate selection.

Long-term outcomes of CT-guided percutaneous cryoablation of T1a and T1b renal cell carcinoma

PURPOSE

We aimed to evaluate the long-term outcomes of computed tomography-guided percutaneous cryoablation (PCA) for biopsy-confirmed renal cell carcinoma (RCC).

METHODS

This was a single-center, retrospective study investigating all patients treated with PCA between January 2010 and February 2019 for RCC tumors. Primary outcome measures included overall survival (OS), disease-free survival (DFS), progression-free survival (PFS) and cancer-specific survival (CSS). Secondary outcome measures included kidney function, complications, technical success, hospital stay, procedural time, and the identification of factors affecting the primary outcomes.

RESULTS

Fifty-three consecutive patients with 54 lesions (T1a: 49/54; T1b: 5/54) were included. Mean tumor diameter was 28.0±8.5 mm and mean R.E.N.A.L. score was 7.2±2.0. Technical success was 100% (54/54 lesions) after two reinterventions for incomplete ablation. Mean follow-up time was 46.7±28.6 months (range, 3-122 months). Local recurrence was noted in 5 patients (9.2%). According to Kaplan-Meyer analysis, OS was 98.2%, 94.2%, 71.2%, and 58.2% at 1, 3, 5, and 8 years. One patient (1.9%) died of cancer and CSS was 95.8% at 8 years. DFS was 100.0%, 95.5%, and 88.6%, and PFS was 100%, 94.3%, and 91.0%, at 1, 2, and 5 years. Clavien-Dindo grade II complication rate was 7.8% (5/64 procedures). There were no complications classified as grade III or greater. Mean creatinine increase was 7.1±6.3 μm/L (p = 0.31). No patient advanced to dialysis during follow up. Mean procedural time was 163±45 min. Median hospital stay was 2.0 days (IQR, 1-2.5 days). Diabetes was the only independent predictor of decreased OS (hazard ratio 4.3, 95% CI 0.043-0.914; p = 0.038).

CONCLUSION

PCA for stage T1a and T1b RCC provides favorable long-term oncological and renal function preservation outcomes, with acceptable complication rates.

Hybrid Simulation and Planning Platform for Cryosurgery with Microsoft HoloLens

Cryosurgery is a technique of growing popularity involving tissue ablation under controlled freezing. Technological advancement of devices along with surgical technique improvements have turned cryosurgery from an experimental to an established option for treating several diseases. However, cryosurgery is still limited by inaccurate planning based primarily on 2D visualization of the patient’s preoperative images. Several works have been aimed at modelling cryoablation through heat transfer simulations; however, most software applications do not meet some key requirements for clinical routine use, such as high computational speed and user-friendliness. This work aims to develop an intuitive platform for anatomical understanding and pre-operative planning by integrating the information content of radiological images and cryoprobe specifications either in a 3D virtual environment (desktop application) or in a hybrid simulator, which exploits the potential of the 3D printing and augmented reality functionalities of Microsoft HoloLens. The proposed platform was preliminarily validated for the retrospective planning/simulation of two surgical cases. Results suggest that the platform is easy and quick to learn and could be used in clinical practice to improve anatomical understanding, to make surgical planning easier than the traditional method, and to strengthen the memorization of surgical planning.

Percutaneous Cryoablation of Lower Limb Soft-Tissue Venous Malformations: Preliminary Results of Long-Term Efficacy

PURPOSE

To retrospectively evaluate long-term efficacy of percutaneous cryoablation for lower limb soft-tissue venous malformations.

MATERIALS AND METHODS

Nine patients (mean age, 36.6 years) with lower limb soft-tissue venous malformations were included. Cryoablation was performed percutaneously using an argon-based system. Adverse events (AE) using the Common Terminology Criteria for AEs version 4.0 were evaluated. The visual analog scale (VAS) scores and lesion volumes measured on magnetic resonance imaging were also evaluated at 12 months and 5-6 years.

RESULTS

Technical success (i.e., complete coverage of the lesion by an iceball) was achieved in eight of the nine patients. All patients developed a total of 14 grade 1 or 2 adverse events. The mean (± standard deviation) VAS score was 6.0 (± 1.7) before therapy, whereas it was 0.14 (± 0.27) at 12 months and 0.97 (± 1.3) at 5-6 years (58-78 months). Complete pain relief was obtained in 6 and 5 patients at 12 months and 5-6 years, respectively. The median lesion volume was 2.49 mL before therapy, whereas it was 0.26 mL at 12 months and 0.35 mL at 5-6 years.

CONCLUSION

Percutaneous cryoablation of lower limb soft-tissue venous malformations achieved considerable pain relief and lesion shrinkage for 5-6 years in this small preliminary study.

LEVEL OF EVIDENCE

Level 4, Case Series.

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.

Effect of Cryoablation Treatment on the Protein Expression Profile of Low-Grade Central Chondrosarcoma Identified by LC-ESI-MS/MS

The use of cryoablation/cryosurgery in treating solid tumors has been proven as a unique technique that uses lethal temperatures to destroy the tumors and impart better functions for the affected organs. This novel technique recently demonstrated the best clinical results in chondrosarcoma (CSA) with faster recovery, less recurrence, and metastasis. Due to the resistant nature of CSA to chemo and radiation therapy, cryoablation comes to light as the best alternative approach. Therefore, for the first time, we aimed to compare CSA-untreated with cryoablation treated samples to discover some potential markers that may provide various clues in terms of diagnosis and pathophysiology and may facilitate the development of novel methods to treat sarcoma efficiently. To find the altered proteins among both groups, a mass-based label-free approach was employed and identified a total of 160 significantly altered proteins. Among these, 138 proteins were dysregulated with <1- to -0.1-fold, 18 proteins were up-regulated with >3 folds, and four proteins were similarly expressed in the untreated group compared to the treated. Interestingly, the differential expressions of proteins from the untreated group showed contrast expressions in the treated group. Furthermore, the functional enrichment analysis revealed that most of the identified proteins from this study were associated with various significant pathways such as glycolysis, MAPK activation, PI3K-Akt signaling, extracellular matrix degradation, etc. In addition, two protein expressions, such as fibronectin and annexin-1, were validated by immunoblot analysis. Therefore, this study signifies the most comprehensive discovery of altered protein expressions to date and the first large-scale detection of protein profiles from CSA-cryoablation treated compared to untreated. This work may serve as the basis for future research to open novel treatment options for chondrosarcoma.

The Impact of Placement Errors on the Tumor Coverage in MRI-Guided Focal Cryoablation of Prostate Cancer

RATIONALE AND OBJECTIVES

There have been multiple investigations defining and reporting the effectiveness of focal cryoablation as a treatment option for organ-confined prostate cancer. However, the impact of cryo-needle/probe placement accuracy within the tumor and gland has not been extensively studied. We analyzed how variations in the placement of the cryo-needles, specifically errors leading to incomplete ablation, may affect prostate cancer's resulting cryoablation.

MATERIALS AND METHODS

We performed a study based on isothermal models using Monte Carlo simulations to analyze the impact of needle placement errors on tumor coverage and the probability of positive ablation margin. We modeled the placement error as a Gaussian noise on the cryo-needle position. The analysis used retrospective MRI data of 15 patients with biopsy-proven, unifocal, and MRI visible prostate cancer to calculate the impact of placement error on the volume of the tumor encompassed by the -40°C and -20°C isotherms using one to four cryo-needles.

RESULTS

When the standard deviation of the placement error reached 3 mm, the tumor coverage was still above 97% with the -20°C isotherm, and above 81% with the -40°C isotherm using two cryo-needles or more. The probability of positive margin was significantly lower considering the -20°C isotherm (0.04 for three needles) than using the -40°C isotherm (0.66 for three needles).

CONCLUSION

The results indicated that accurate cryo-needle placement is essential for the success of focal cryoablation of prostate cancer. The analysis shows that an admissible targeting error depends on the lethal temperature considered and the number of cryo-needles used.

[Should we start with ablation or try a pill first? Is early cryoablation for atrial fibrillation really better?]

There is a worldwide trend towards earlier pulmonary vein isolation (PVI) in the treatment of atrial fibrillation (AF). Recently, the STOP-AF and EARLY-AF trials were published, comparing cryoablation and antiarrhythmic drugs as first line rhythm therapy for paroxysmal AF. Both studies did not show a difference in incidence of mortality or heart failure. The positive result was driven by a favorable difference of (mostly asymptomatic) recurrences, AF burden (which was also very low in the control groups) and a small improvement of Quality of Life. The clinical relevance of this outcome is limited. We advise to stick to the suggested steps in the guideline: evaluating the symptoms over a longer period of time, implementing lifestyle interventions and use medications for rate control, rhythm control if symptoms persist and for stroke prevention. If AF and symptoms persist ablation is an excellent treatment option with little risk.

Cryobiopsy in Lung Cancer Diagnosis-A Literature Review

Optimizing the diagnosis of lung cancer represents a challenge, as well as a necessity, for improving the low survival of these patients. Flexible bronchoscopy with forceps biopsy is one of the key diagnostic procedures used for lung tumors. The small sample size and crush artifacts are several factors that can often limit access to a complete diagnosis, therefore leading to the need of repeating the bronchoscopy procedure or other invasive diagnostic methods. The bronchoscopic cryobiopsy is a recent technique that proved its utility in the diagnosis of both endobronchial and peripheral lung tumors. In comparison with conventional forceps biopsy, studies report a higher diagnostic yield and a superior quality of the collected samples for both the histopathological and the molecular diagnosis of lung cancer. This method shows promising results in sampling lung tissue, alone, or in conjunction with fluoroscopy or radial endobronchial ultrasound (r-EBUS). With a good safety and cost-benefit profile, this novel method has the potential to improve the diagnosis, and therefore the management of lung cancer patients. The objective of this narrative review is to provide a comprehensive review of the recent data regarding the advantages of cryobiopsy and r-EBUS in lung cancer diagnosis.

Oral Ursodeoxycholic Acid Crosses the Blood Retinal Barrier in Patients with Retinal Detachment and Protects Against Retinal Degeneration in an Ex Vivo Model

Rhegmatogenous retinal detachment (RD) is a threatening visual condition and a human disease model for retinal degenerations. Despite successful reattachment surgery, vision does not fully recover, due to subretinal fluid accumulation and subsequent photoreceptor cell death, through mechanisms that recapitulate those of retinal degenerative diseases. Hydrophilic bile acids are neuroprotective in animal models, but whether they can be used orally for retinal diseases is unknown. Ursodeoxycholic acid (UDCA) being approved for clinical use (e.g., in cholestasis), we have evaluated the ocular bioavailability of oral UDCA, administered to patients before RD surgery. The level of UDCA in ocular media correlated with the extent of blood retinal barrier disruption, evaluated by the extent of detachment and the albumin concentration in subretinal fluid. UDCA, at levels measured in ocular media, protected photoreceptors from apoptosis and necrosis in rat retinal explants, an ex vivo model of RD. The subretinal fluid from UDCA-treated patients, collected during surgery, significantly protected rat retinal explants from cell death, when compared to subretinal fluid from control patients. Pan-transcriptomic analysis of the retina showed that UDCA upregulated anti-apoptotic, anti-oxidant, and anti-inflammatory genes. Oral UDCA is a potential neuroprotective adjuvant therapy in RD and other retinal degenerative diseases and should be further evaluated in a clinical trial.

Cryoablation for Palliation of Painful Bone Metastases: The MOTION Multicenter Study

PURPOSE

To assess the clinical effectiveness of cryoablation for palliation of painful bone metastases.

MATERIALS AND METHODS

MOTION (Multicenter Study of Cryoablation for Palliation of Painful Bone Metastases) (ClinicalTrials.gov NCT02511678) was a multicenter, prospective, single-arm study of adults with metastatic bone disease who were not candidates for or had not benefited from standard therapy, that took place from February 2016 to March 2018. At baseline, participants rated their pain using the Brief Pain Inventory-Short Form (reference range from 0 to 10 points); those with moderate to severe pain, who had at least one metastatic candidate tumor for ablation, were included. The primary effectiveness endpoint was change in pain score from baseline to week 8. Participants were followed for 24 weeks after treatment. Statistical analyses included descriptive statistics and logistic regression to evaluate changes in pain score over the postprocedure follow-up period.

RESULTS

A total of 66 participants (mean age, 60.8 years ± 14.3 [standard deviation]; 35 [53.0%] men) were enrolled and received cryoablation; 65 completed follow-up. Mean change in pain score from baseline to week 8 was -2.61 points (95% CI: -3.45, -1.78). Mean pain scores improved by 2 points at week 1 and reached clinically meaningful levels (more than a 2-point decrease) after week 8; scores continued to improve throughout follow-up. Quality of life improved, opioid doses were stabilized, and functional status was maintained over 6 months. Serious adverse events occurred in three participants.

CONCLUSION

Cryoablation of metastatic bone tumors provided rapid and durable pain palliation, improved quality of life, and offered an alternative to opioids for pain control.Keywords: Ablation Techniques, Metastases, Pain Management, Radiation Therapy/OncologySupplemental material is available for this article.© RSNA, 2021.

A Non-Fourier Bioheat Transfer Model for Cryosurgery of Tumor Tissue with Minimum Collateral Damage

BACKGROUND AND OBJECTIVES

Incorporation of non-Fourier heat conduction while studying heat transfer phenomena in biological materials has emerged has an important approach as it predicts better and more realistic results than Fourier based models. In this article we have proposed a non-Fourier computational model and applied the same to simulate cryosurgery of lung tumor and attempted minimization of freezing damage of healthy lung tissue using pulsed laser irradiation.

METHODS

A non-Fourier bioheat transfer model for phase change in biological tissues is solved via a Fourier heat conduction based solution approach. A unified model is proposed combining all variants of bioheat models: Fourier's heat conduction based Pennes' bioheat model, hyperbolic heat conduction model and dual phase lag model. The proposed model takes into account the different thermophysical properties of frozen and unfrozen regions. In order to mimic the actual biotransport process, the blood perfusion and metabolic heat generation are switched off in the frozen region. Implicit source based enthalpy method is used to model phase change process. A new iterative enthalpy update equation is developed for capturing evolution of freezing front implicitly. Finite Volume based numerical discretization technique is used to discretize the governing PDE. The resulting discrete algebraic equation set is solved implicitly by Tri-diagonal Matrix Algorithm. The proposed model is verified with existing results from the literature.

RESULTS

For Fourier heat conduction, freezing time of 99.99% of tumor is 1247s, which increases to 1267s for τ_q= 5s (τ_T= 0s) and again reduces to 1255s for τ_q= 5s and τ_T= 3s. τ_q and τ_T are phase lag parameters for non-Fourier heat conduction. For τ_q= 5s and τ_T= 0.05s, the freezing damage of healthy tissue decreases by 23.76% when pulsed laser irradiation (I_o = 10⁶ W/m²) is used to warm the neighboring healthy tissue.

CONCLUSIONS

So non-Fourier bioheat transport models are better and more accurate in predicting temperature history, freezing time and freezing front propagation as compared to Fourier based models. Pulsed laser irradiation can prove to be a very efficient technique in minimizing collateral damage during cryosurgery.

MRI predicts prostatic urethral involvement in men undergoing radical prostatectomy: implications for cryo-ablation of localized prostate cancer

PURPOSE

To determine whether multi-parametric magnetic resonance imaging (mpMRI) can reliably predict proximity of prostate cancer to the prostatic urethra in a contemporary series of men undergoing radical prostatectomy (RP) at two academic centers.

METHODS

Clinical characteristics of consecutive men undergoing pre-operative mpMRI prior to RP and whole-mount axial serial step-sectioned pathology examination at two academic centers between Jun 2016 and Oct 2018 were analyzed retrospectively. Every tumor was characterized by its pathologic minimum distance to the prostatic urethral lumen (pMDUL). Only the cancer closest to the urethra represented the prostatic urethral index lesion. The radiologic minimum distance of the index lesion to the prostatic urethral lumen was measured and noted as ≤ 5 mm versus  > 5 mm. The sensitivity, specificity, positive and negative predicting values (PPV and NPV) and area under the receivers operating characteristics curve (AUC) were calculated for performance of mpMRI for predicting pMDUL ≤ 5 mm.

RESULTS

Of the 163 surgical specimens examined, 112 (69%) exhibited a pMDUL ≤ 5 mm. These men had significantly higher grade group (GG) and advanced pathological and clinical stage. The rates of high PI-RADS score and presence of gross extracapsular extension were also significantly greater for the group with pMDUL ≤ 5 mm. The AUC, sensitivity, specificity, PPV, and NPV were 0.641, 51.8, 76.5, 82.9, and 42.4%, respectively, for mpMRI to predict pMDUL < 5 mm.

CONCLUSIONS

Nearly 70% of men undergoing RP present with tumor within 5 mm of the prostatic urethra. These tumors present higher risk characteristics, and mpMRI exhibited moderate performance and high PPV in their pre-operative detection. Physicians performing partial gland ablation should take these results into consideration during treatment selection and planning.

Efficacy of cryoablation in idiopathic and non-idiopathic atrial fibrillation patients

OBJECTIVES AND BACKGROUND

Studies assessing the unicentric and prospective comparison of efficacy of cryoballoon pulmonary vein isolation in idiopathic and non-idiopathic atrial fibrillation (AF) patients are missing. The aim of this study was to compare a single procedural outcome in these subgroups of AF patients.

METHODS

A total of 208 patients with drug resistant AF were included in this study. Among them, 36 patients had idiopathic AF and 172 patients had non-idiopathic AF. The efficacy endpoint was freedom from any atrial arrhythmia lasting >30 s after a 3-months blanking period.

RESULTS

The freedom from atrial arrhythmias without antiarrhythmic drugs after 1 and 3 years of follow-up, respectively, was 85.2 % and 70.4 % in patients with idiopathic AF; and 64.6 % and 39.9 % in patients with non-idiopathic AF (p=0.021). Moreover, the success rate when analysing only paroxysmal AF patients after 1 and 3 years of follow-up, respectively, was 95.7 % and 82 % in patients with idiopathic AF; and 72.6 % and 47 % in patients with non-idiopathic AF (p=0.022).

CONCLUSIONS

A single cryoballoon pulmonary vein isolation was more effective in preventing atrial arrhythmias relapses in idiopathic AF patients compared to non-idiopathic AF patients. The best efficacy outcomes were observed in patients with paroxysmal idiopathic AF (Tab. 5, Fig. 2, Ref. 25).