Survival After Robotic-assisted Prostatectomy for Localized Prostate Cancer: An Epidemiologic Study.

BACKGROUNDS: To determine the potential survival benefit associated with robotic-assisted laparoscopic prostatectomy (RALP) compared to open radical prostatectomy (ORP) for prostate cancer. SUMMARY OF BACKGROUND DATA: RALP has become the dominant surgical approach for localized disease in the absence of randomized clinical evidence and despite of the factor that RALP is more expensive than ORP. METHODS: We performed a cohort study involving patients who underwent RALP and ORP for localized prostate cancer at the Commission on Cancer- accredited hospitals in the United States. Overall survival was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. An interrupted time-series analysis using the surveillance, epidemiology, and end results program database was also performed. RESULTS: From 2010 to 2011, 37,645 patients received RALP and 12,655 patients received ORP. At a median follow-up of 60.7 months, RALP was associated with improved overall survival by both univariate [hazard ratio (HR), 0.69; P < 0.001] and multivariate analysis (HR, 0.76; P < 0.001) compared with ORP. Propensity score-matched analysis demonstrated improved 5-year all-cause mortality (3.9% vs 5.5%, HR, 0.73; P < 0.001) for RALP. The interrupted time-series analysis demonstrated the adoption of robotic surgery coincided with a systematic improvement in the 5-year cancer-specific survival rate of 0.17% (95% confidence interval, 0.06-0.25) per year after 2003 (P = 0.004 for change of trend), as compared to the time before adoption of RALP (1998-2003, annual percentage change, 0.01%; 95% confidence interval, -0.06 to 0.08). Sensitivity analysis suggested that the results from the interrupted time-series analysis were consistent with the improvement in the all-cause mortality demonstrated in the survival analysis (P = 0.87). CONCLUSIONS: In this epidemiologic analysis, RALP was associated with a small but statistically significant improvement in 5-year all-cause mortality compared to ORP for localized prostate cancer. This is the first time in the literature to report a survival benefit with RALP. Our findings have significant quality and cost implications, and provide assurance regarding a dominant adoption of more expensive technology in the absence of randomized controlled trials.

Definitive Pelvic Radiotherapy and Survival of Patients With Newly Diagnosed Metastatic Anal Cancer.

Background: Chemotherapy with or without pelvic radiotherapy (RT) is included in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for metastatic anal cancer (MAC), despite limited clinical evidence for RT in this setting. In addition, increasing evidence shows that local therapies, including RT, may increase patient survival for some types of metastatic cancers. The purpose of this study was to evaluate the patterns of care and association between definitive pelvic RT and overall survival (OS) for patients with MAC. Methods: The National Cancer Database was analyzed to evaluate OS of patients with newly diagnosed MAC treated with chemotherapy with or without pelvic RT. Those who did not undergo treatment, treated with surgery, or without baseline variables were excluded. OS was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. Results: From 2004 through 2015, 437 patients received chemotherapy alone and 1,020 received pelvic chemoradiotherapy (CRT). At a median follow-up of 17.3 months, CRT was associated with improved OS on univariate (P<.001) and multivariate analysis (hazard ratio [HR], 0.70; 95% CI, 0.61-0.81; P<.001). Propensity score-matched analysis demonstrated superior median survival (21.3 vs 15.9 months) and 2-year OS rates (46% vs 34%) with CRT compared with chemotherapy alone (P<.001). Landmark analyses limited to long-term survivors of ≥1, ≥2, and ≥4 years showed improved OS with CRT in all subsets (all P<.05). CRT with therapeutic doses (≥45 Gy) was associated with longer median survival than palliative doses (<45 Gy) and chemotherapy alone (24.9 vs 10.9 vs 15.6 months, respectively; P<.001). The benefit of CRT was present among not only those with distant lymph node metastasis (HR, 0.63; P=.04) but also those with distant organ disease (HR, 0.74; P<.001). Conclusions: In this large hypothesis-generating analysis, patients with newly diagnosed MAC who received definitive pelvic RT with chemotherapy lived significantly longer than those who received chemotherapy alone. Prospective trials evaluating definitive local RT for MAC are warranted.

A microelectronic portal imaging device for image guided conformal microirradiation of murine cancer models.

Image guided conformal small animal orthovoltage microirradiators are currently under development to perform radiobiological experiments with preclinical cancer models. An important component of these instruments is the treatment delivery image guidance system, a microelectronic portal imaging device (µEPID). Here, we present the design and implementation of a µEPID, specifically designed and constructed for small animal orthovoltage microirradiators. The µEPID can acquire images in the range of 60 kVp to 320 kVp x-ray photon energies and can endure high doses from orthovoltage beams without radiation damage. The µEPID can acquire 200 µm resolution images at a rate of 17 frames per second for online in vivo co-registration between irradiation beams and small animal anatomy. An exposure with less than 1% of a 2 Gy treatment field is required for imaging, which is an adequate ratio between imaging dose and treatment dose to avoid undesired irradiation of healthy tissue or alteration of the preclinical cancer model. The µEPID was calibrated for microdosimetry with a precision of 4.1% with respect to an ion chamber, used as a gold standard. To validate the in vivo device performance, irradiations of lung, brain, and xenograft breast cancer preclinical models were performed and analyzed.

Implementation of Magnetic Resonance Imaging-Guided Radiation Therapy in Routine Care: Opportunities and Challenges in the United States.

Purpose: Magnetic resonance image (MRI)-guided radiation therapy with the 1.5 Tesla magnetic resonance linear accelerator (MR-Linac) is a rapidly evolving and emerging treatment. The MR-Linac literature mainly focused on clinical and technological factors in technology implementation, but it is relatively silent on health care system-related factors. Consequently, there is a lack of understanding of opportunities and barriers in implementing the MR-Linac from a health care system perspective. This study addresses this gap with a case study of the US health care system. Methods and Materials: An exploratory, qualitative research design was used. Data collection consisted of 23 semistructured interviews ranging from clinical experts at the radiation therapy and radiology department to insurance commissioners in 7 US hospitals. Analysis of opportunities and barriers was guided by the Nonadoption, Abandonment, Scale-up, Spread and Sustainability framework for new medical technologies in health care organizations. Results: Opportunities included high-precision MR-guidance during radiation therapy with potential continued technical advances and better patient outcomes. MR-Linac also offers opportunities for research, professional, and economic development. Barriers included the lack of empirical evidence of clinical effectiveness, technological complexity, and large staffing and structural investments. Furthermore, the presence of patients with disadvantaged socioeconomic background, and the lack of appropriate reimbursement as well as regulatory conditions can hinder technology implementation. Conclusions: Our study confirms the current literature on implementing the MR-Linac, but also reveals additional challenges for the US health care system. Alongside the well-known clinical and technical factors, also professional, socioeconomic, market, and governing influences affect technology implementation. These findings highlight new connections to facilitate technology uptake and provide a richer start to understanding its long-term effect.

Novel chemo-sensitizing agent, ERW1227B, impairs cellular motility and enhances cell death in glioblastomas.

Glioblastomas display variable phenotypes that include increased drug-resistance associated with enhanced migratory and anti-apoptotic characteristics. These shared characteristics contribute to failure of clinical treatment regimens. Identification of novel compounds that promote cell death and impair cellular motility is a logical strategy to develop more effective clinical protocols. We recently described the ability of the small molecule, KCC009, a tissue transglutaminase (TG2) inhibitor, to sensitize glioblastoma cells to chemotherapy. In the current study, we synthesized a series of related compounds that show variable ability to promote cell death and impair motility in glioblastomas, irrespective of their ability to inhibit TG2. Each compound has a 3-bromo-4,5-dihydroisoxazole component that presumably reacts with nucleophilic cysteine thiol residues in the active sites of proteins that have an affinity to the small molecule. Our studies focused on the effects of the compound, ERW1227B. Treatment of glioblastoma cells with ERW1227B was associated with both down-regulation of the PI-3 kinase/Akt pathway, which enhanced cell death; as well as disruption of focal adhesive complexes and intracellular actin fibers, which impaired cellular mobility. Bioassays as well as time-lapse photography of glioblastoma cells treated with ERW1227B showed cell death and rapid loss of cellular motility. Mice studies with in vivo glioblastoma models demonstrated the ability of ERW1227B to sensitize tumor cells to cell death after treatment with either chemotherapy or radiation. The above findings identify ERW1227B as a potential novel therapeutic agent in the treatment of glioblastomas.

Feasibility of small animal cranial irradiation with the microRT system.

PURPOSE: To develop and validate methods for small-animal CNS radiotherapy using the microRT system. MATERIALS AND METHODS: A custom head immobilizer was designed and built to integrate with a pre-existing microRT animal couch. The Delrin couch-immobilizer assembly, compatible with multiple imaging modalities (CT, microCT, microMR, microPET, microSPECT, optical), was first imaged via CT in order to verify the safety and reproducibility of the immobilization method. Once verified, the subject animals were CT-scanned while positioned within the couch-immobilizer assembly for treatment planning purposes. The resultant images were then imported into CERR, an in-house-developed research treatment planning system, and registered to the microRTP treatment planning space using rigid registration. The targeted brain was then contoured and conformal radiotherapy plans were constructed for two separate studies: (1) a whole-brain irradiation comprised of two lateral beams at the 90 degree and 270 degree microRT treatment positions and (2) a hemispheric (left-brain) irradiation comprised of a single A-P vertex beam at the 0 degree microRT treatment position. During treatment, subject animals (n=48) were positioned to the CERR-generated treatment coordinates using the three-axis microRT motor positioning system and were irradiated using a clinical Ir-192 high-dose-rate remote after-loading system. The radiation treatment course consisted of 5 Gy fractions, 3 days per week. 90% of the subjects received a total dose of 30 Gy and 10% received a dose of 60 Gy. RESULTS: Image analysis verified the safety and reproducibility of the immobilizer. CT scans generated from repeated reloading and repositioning of the same subject animal in the couch-immobilizer assembly were fused to a baseline CT. The resultant analysis revealed a 0.09 mm average, center-of-mass translocation and negligible volumetric error in the contoured, murine brain. The experimental use of the head immobilizer added 0.1 mm to microRT spatial uncertainty along each axis. Overall, the total spatial uncertainty for the prescribed treatments was +/-0.3 mm in all three axes, a 0.2 mm functional improvement over the original version of microRT. Subject tolerance was good, with minimal observed side effects and a low procedure-induced mortality rate. Throughput was high, with average treatment times of 7.72 and 3.13 min/animal for the whole-brain and hemispheric plans, respectively (dependent on source strength). CONCLUSIONS: The method described exhibits conformality more in line with the size differential between human and animal patients than provided by previous prevalent approaches. Using pretreatment imaging and microRT-specific treatment planning, our method can deliver an accurate, conformal dose distribution to the targeted murine brain (or a subregion of the brain) while minimizing excess dose to the surrounding tissue. Thus, preclinical animal studies assessing the radiotherapeutic response of both normal and malignant CNS tissue to complex dose distributions, which closer resemble human-type radiotherapy, are better enabled. The procedural and mechanistic framework for this method logically provides for future adaptation into other murine target organs or regions.