Proactive rectal warming during total-gland prostate cryoablation

Advances in Image-Guided Ablation Therapies for Solid Tumors

Image-guided solid tumor ablation methods have significantly advanced in their capability to target primary and metastatic tumors. These techniques involve noninvasive or percutaneous insertion of applicators to induce thermal, electrochemical, or mechanical stress on malignant tissue to cause tissue destruction and apoptosis of the tumor margins. Ablation offers substantially lower risks compared to traditional methods. Benefits include shorter recovery periods, reduced bleeding, and greater preservation of organ parenchyma compared to surgical intervention. Due to the reduced morbidity and mortality, image-guided tumor ablation offers new opportunities for treatment in cancer patients who are not candidates for resection. Currently, image-guided ablation techniques are utilized for treating primary and metastatic tumors in various organs with both curative and palliative intent, including the liver, pancreas, kidneys, thyroid, parathyroid, prostate, lung, breast, bone, and soft tissue. The invention of new equipment and techniques is expanding the criteria of eligible patients for therapy, as now larger and more high-risk tumors near critical structures can be ablated. This article provides an overview of the different imaging modalities, noninvasive, and percutaneous ablation techniques available and discusses their applications and associated complications across various organs.

Primary Total Prostate Cryoablation for Localized High-Risk Prostate Cancer: 10-Year Outcomes and Nomograms

The role of prostate cryoablation was still uncertain for patients with high-risk prostate cancer (PC). This study was designed to investigate 10-year disease-free survival and establish a nomogram in localized high-risk PC patients. Between October 2008 and December 2020, 191 patients with high-risk PC who received primary total prostate cryoablation (PTPC) were enrolled. The primary endpoint was biochemical recurrence (BCR), defined using Phoenix criteria. The performance of pre-operative and peri-operative nomograms was determined using the Harrell concordance index (C-index). Among the cohort, the median age and PSA levels at diagnosis were 71 years and 12.3 ng/mL, respectively. Gleason sum 8-10, stage ≥ T3a, and PSA > 20 ng/mL were noted in 27.2%, 74.4%, and 26.2% of patients, respectively. During the median follow-up duration of 120.4 months, BCR-free rates at 1, 3, 5, and 10 years were 92.6%, 76.6%, 66.7%, and 50.8%, respectively. The metastasis-free, cancer-specific, and overall survival rates were 89.5%, 97.4%, and 90.5% at 10 years, respectively. The variables in the pre-operative nomogram for BCR contained PSA at diagnosis, clinical stage, and Gleason score (C-index: 0.73, 95% CI, 0.67-0.79). The variables in the peri-operative nomogram for BCR included PSA at diagnosis, Gleason score, number of cryoprobes used, and PSA nadir (C-index: 0.83, 95% CI, 0.78-0.88). In conclusion, total prostate cryoablation appears to be an effective treatment option for selected men with high-risk PC. A pre-operative nomogram can help select patients suitable for cryoablation. A peri-operative nomogram signifies the importance of the ample use of cryoprobes and helps identify patients who may need early salvage treatment.

Functional and oncological outcomes of salvage cryosurgery for radiorecurrent prostate cancer

OBJECTIVES

To evaluate the oncological and functional outcomes of salvage cryosurgery (SCS) for radiorecurrent prostate cancer (rrPCa).

PATIENTS AND METHODS

A total of 169 consecutive patients with biopsy confirmed rrPCa were retrospectively analysed. All patients underwent SCS in a single referral centre between 2006 and 2018. The primary outcome was biochemical recurrence-free survival (BRFS) according to the Phoenix definition (prostate-specific antigen [PSA] nadir +2 ng/mL). The secondary outcomes were overall survival, BRFS defined as a PSA level of >0.5 ng/mL, metastasis-free survival, androgen-deprivation therapy (ADT)-free survival, and functional outcomes. Complications were classified according to the Clavien-Dindo system. PSA was measured every 3-6 months postoperatively. Functional outcomes were scored as reported by patients at outpatient visits. Kaplan-Meier survival analysis and uni- and multivariable Cox regression were performed.

RESULTS

The median (interquartile range) follow-up was 36 (18-66) months. The BRFS after 5 and 8 years was 52% (95% confidence interval [CI] 43-62%) and 45% (95% CI 35-57%), respectively. At multivariable analysis PSA level at initial diagnosis, initial treatment, interval between primary treatment and SCS, age at SCS, and post-SCS PSA nadir were significant factors for BRFS. The 5-year ADT-free survival was 70% (95% CI 62-79%). Clavien-Dindo Grade ≥III complications occurred in 1.2% (two/169) of patients. In all, 19% (29/156) of patients had new-onset urinary incontinence defined as >1 pad/24 h and 92% (57/62) of patients had new-onset erectile dysfunction. Persistent urinary fistula occurred in 6.5% (11/169) of patients.

CONCLUSIONS

The present study shows acceptable oncological outcomes of SCS considering the salvage character of the treatment. The occurrence of serious complications such as urinary incontinence and fistula should not be underestimated.

Thermo-sensitive nanoparticles for triggered release of siRNA

Efficient delivery of small interfering RNA (siRNA) is crucially required for cancer gene therapy. Herein, a thermo-sensitive copolymer with a simple structure, poly (ethylene glycol) methyl ether acrylate-b-poly (N-isopropylacrylamide) (mPEG-b-PNIPAM) was developed. A novel kind of thermo-sensitive nanoparticles (DENPs) was constructed for the cold-shock triggered release of siRNA by double emulsion-solvent evaporation method using mPEG-b-PNIPAM and a cationic lipid, 3β [N-(N', N'-dimethylaminoethane)-carbamoyl] cholesterol [DC-Chol]. DENPs were observed by transmission electron microscopy and dynamical light scattering before and after 'cold shock' treatment. The encapsulation efficiency (EE) of siRNA in DENPs, which was measured by fluorescence spectrophotometer was 96.8% while it was significantly reduced to be 23.2% when DC-Chol was absent. DENPs/siRNA NPs exhibited a thermo-sensitive siRNA release character that the cumulatively released amount of siRNA from cold shock was approximately 2.2 folds higher after 7 days. In vitro luciferase silencing experiments indicated that DENPs showed potent gene silencing efficacy in HeLa-Luc cells (HeLa cells steadily expressed luciferase), which was further enhanced by a cold shock. Furthermore, MTT assay showed that cell viability with DENPs/siRNA up to 200 nM remained above 80%. We also observed that most of siRNA was accumulated in kidney mediated by DENPs instead of liver and spleen in vivo experiments. Thus, DENPs as a cold shock responsive quick release model for siRNA or hydrophilic macromolecules delivery provide a new way to nanocarrier design and clinic therapy.