Real-World Outcomes of Patients Starting Intravenous and Transitioning to Subcutaneous Vedolizumab in Inflammatory Bowel Disease

BACKGROUND

Real-world data on starting intravenous (IV) vedolizumab (VDZ) and transitioning to subcutaneous (SC) treatment in inflammatory bowel disease (IBD) are scarce.

AIMS

To assess treatment outcomes of patients with IBD starting IV VDZ and switching to SC VDZ in routine clinical care.

METHODS

Adult patients with IBD switching from IV to SC VDZ treatment between 1 March 2020 and 31 December 2021 were identified from the Swedish IBD quality register. The primary outcome was SC VDZ persistence. Secondary outcomes included clinical remission, changes in quality of life (QoL) according to EuroQual 5-Dimensions 5-Levels (EQ-5D-5L) and the Short-Health Scale (SHS) and inflammatory markers, including faecal Calprotectin (FCP).

RESULTS

Altogether, 406 patients with IBD (Crohn's disease, n = 181; ulcerative colitis, n = 225) were identified. After a median follow-up of 30 months from starting IV VDZ treatment, the persistence rates were 98%(178/181) in Crohn's disease and 94% (211/225) in ulcerative colitis. Most patients (84%) transitioned during maintenance therapy, and the median follow-up from switch to SC VDZ was 10 months. Compared to baseline, statistically significant improvements were observed in all domains of the SHS, EQ-5D index value and visual analogue scale. Median (interquartile range) FCP concentrations (μg/g) decreased from 459 (185-1001) to 65 (26-227) in Crohn's disease (n = 45; p < 0.001) and from 646 (152-1450) to 49 (20-275) in ulcerative colitis (n = 58; p < 0.001).

CONCLUSION

Initiating IV VDZ and switching to SC treatment was associated with high persistence rates and improvements in measures of QoL and FCP. These findings are reassuring for patients who start IV VDZ and switch to SC VDZ.

SOX2 and OCT4 mediate radiation and drug resistance in pancreatic tumor organoids

Pancreatic cancer has a five-year survival rate of only 10%, mostly due to late diagnosis and limited treatment options. In patients with unresectable disease, either FOLFIRINOX, a combination of 5-fluorouracil (5-FU), oxaliplatin and irinotecan, or gemcitabine plus nab-paclitaxel combined with radiation are frontline standard regimens. However, chemo-radiation therapy has shown limited success because patients develop resistance to chemotherapy and/or radiation. In this study, we evaluated the role of pancreatic cancer stem cells (CSC) using OCT4 and SOX2, CSC markers in mouse pancreatic tumor organoids. We treated pancreatic tumor organoids with 4 or 8 Gy of radiation, 10 μM of 5-FU (5-Fluorouracil), and 100 μM 3-Bromopyruvate (3BP), a promising anti-cancer drug, as a single treatment modalities, and in combination with RT. Our results showed significant upregulation of, OCT4, and SOX2 expression in pancreatic tumor organoids treated with 4 and 8 Gy of radiation, and downregulation following 5-FU treatment. The expression of CSC markers with increasing treatment dose exhibited elevated upregulation levels to radiation and downregulation to 5-FU chemotherapy drug. Conversely, when tumor organoids were treated with a combination of 5-FU and radiation, there was a significant inhibition in SOX2 and OCT4 expression, indicating CSC self-renewal inhibition. Noticeably, we also observed that human pancreatic tumor tissues exhibited heterogeneous and aberrant OCT4 and SOX2 expression as compared to normal pancreas, indicating their potential role in pancreatic cancer growth and therapy resistance. In addition, the combination of 5-FU and radiation treatment exhibited significant inhibition of the β-catenin pathway in pancreatic tumor organoids, resulting in sensitization to treatment and organoid death. In conclusion, our study emphasizes the crucial role of CSCs in therapeutic resistance in PC treatment. We recommend using tumor organoids as a model system to explore the impact of CSCs in PC and identify new therapeutic targets.

The AAPM/ASTRO 2023 Core Physics Curriculum for Radiation Oncology Residents

PURPOSE

The American Association of Physicists in Medicine Radiation Oncology Medical Physics Education Subcommittee (ROMPES) has updated the radiation oncology physics core curriculum for medical residents in the radiation oncology specialty.

METHODS AND MATERIALS

Thirteen physicists from the United States and Canada involved in radiation oncology resident education were recruited to ROMPES. The group included doctorates and master's of physicists with a range of clinical or academic roles. Radiation oncology physician and resident representatives were also consulted in the development of this curriculum. In addition to modernizing the material to include new technology, the updated curriculum is consistent with the format of the American Board of Radiology Physics Study Guide Working Group to promote concordance between current resident educational guidelines and examination preparation guidelines.

RESULTS

The revised core curriculum recommends 56 hours of didactic education like the 2015 curriculum but was restructured to provide resident education that facilitates best clinical practice and scientific advancement in radiation oncology. The reference list, glossary, and practical modules were reviewed and updated to include recent literature and clinical practice examples.

CONCLUSIONS

ROMPES has updated the core physics curriculum for radiation oncology residents. In addition to providing a comprehensive curriculum to promote best practice for radiation oncology practitioners, the updated curriculum aligns with recommendations from the American Board of Radiology Physics Study Guide Working Group. New technology has been integrated into the curriculum. The updated curriculum provides a framework to appropriately cover the educational topics for radiation oncology residents in preparation for their subsequent career development.

Pancreatic Cancer Derived 3-D Organoids as Clinical Tool to Predict Response to Radiation and Chemo-Radiation Therapy

PURPOSE/OBJECTIVE(S)

Pancreatic cancer (PC) is the fourth leading cause of cancer death in both men and women. The standard of care for patients with locally advanced PC of chemotherapy, stereotactic radiotherapy (RT) or chemo-radiation-therapy has shown highly variable and limited success rates. However, three-dimensional (3D) Pancreatic tumor organoids (PTOs) have shown promise to study tumor response to drugs, and emerging treatments under in vitro conditions. We investigated the potential for using 3D organoids to evaluate the precise radiation and drug dose responses of in vivo PC tumors.

MATERIALS/METHODS

PTOs were created from mouse pancreatic tumor tissues, and their microenvironment was compared to that of in vivo tumors using immunohistochemical staining. The organoids and in vivo PC tumors were treated with fractionated X-ray RT, 3-bromopyruvate (3BP) anti-tumor drug, and with a combination of 3BP + fractionated RT. We quantified treatment response by metabolic imaging and immunofluorescence of αSMA and vimentin markers.

RESULTS

Pancreatic tumor organoids (PTOs) exhibited a similar fibrotic microenvironment and molecular response (as seen by apoptosis biomarker expression) as in vivo tumors. Untreated tumor organoids and in vivo tumor both exhibited proliferative growth of 6 folds the original size after 10 days, whereas no growth was seen for organoids and in vivo tumors treated with 8 (Gray) Gy of fractionated RT. Tumor organoids showed reduced growth rates of 3.2x and 1.8x when treated with 4 and 6 Gy fractionated RT, respectively. Interestingly, combination of 100 µM of 3BP + 4 Gy of RT showed pronounced growth inhibition as compared to 3-BP alone or 4 Gy of radiation alone. Further, we observed overexpression of OCT-4, SOX2, Nanog cancer stem cell markers (CSC) indicated presence of cancer stem cells in tumor organoids which might have some role in resistance to therapies and recurrence in pancreatic cancer.

CONCLUSION

PTOs produced a similar microenvironment and exhibited similar growth characteristics as in vivo tumors following treatment, indicating their potential for predicting in vivo tumor sensitivity and response to RT and combined chemo-RT treatments. Cancer stem cells in pancreatic cancer could be playing a role in resistance to therapies and recurrence in pancreatic cancer.

Interstitial Brachytherapy for Lip Cancer: Technical Aspects to Individualize Treatment Approach and Optimize Outcomes

Primary radiation therapy using interstitial brachytherapy (IBT) provides excellent local tumor control for early-stage squamous cell carcinoma of the lip. Technical aspects of treatment are important to optimize outcomes. In this report, we discuss patient selection criteria, procedural details, and dosimetric considerations for performing IBT for cancers of the lip. Catheters are inserted across the length of tumor entering and exiting approximately 5 mm beyond the palpable tumor extent. A custom mouthpiece is fabricated to facilitate normal tissue sparing. Patients undergo computed tomography imaging, the gross tumor volume is contoured based on physical examination and computed tomography findings, and an individualized brachytherapy plan is generated with the goals of achieving gross tumor volume D90% ≥ 90% and minimizing V150%. Ten patients with primary (n = 8) or recurrent (n = 2) cancers of the lip who received high-dose-rate lip IBT using 2.0- to 2.5-week treatment regimens are described (median prescription: 47.6 Gy in 14 fractions of 3.4 Gy). Local tumor control was 100%. There were no cases of acute grade ≥4 or late grade ≥2 toxicity, and cosmesis scores were graded as good to excellent in all patients. IBT represents an excellent treatment option for patients with lip squamous cell carcinoma. With careful attention to technical considerations furthered described in the present report, high rates of tumor control, low rates of toxicity, and favorable esthetic and functional outcomes can be achieved with IBT for lip cancer.

Pancreatic cancer derived 3D organoids as a clinical tool to evaluate the treatment response

Background and purpose

Pancreatic cancer (PC) is the fourth leading cause of cancer death in both men and women. The standard of care for patients with locally advanced PC of chemotherapy, stereotactic radiotherapy (RT), or chemo-radiation-therapy has shown highly variable and limited success rates. However, three-dimensional (3D) Pancreatic tumor organoids (PTOs) have shown promise to study tumor response to drugs, and emerging treatments under in vitro conditions. We investigated the potential for using 3D organoids to evaluate the precise radiation and drug dose responses of in vivo PC tumors.

Methods

PTOs were created from mouse pancreatic tumor tissues, and their microenvironment was compared to that of in vivo tumors using immunohistochemical and immunofluorescence staining. The organoids and in vivo PC tumors were treated with fractionated X-ray RT, 3-bromopyruvate (3BP) anti-tumor drug, and combination of 3BP + fractionated RT.

Results

Pancreatic tumor organoids (PTOs) exhibited a similar fibrotic microenvironment and molecular response (as seen by apoptosis biomarker expression) as in vivo tumors. Untreated tumor organoids and in vivo tumor both exhibited proliferative growth of 6 folds the original size after 10 days, whereas no growth was seen for organoids and in vivo tumors treated with 8 (Gray) Gy of fractionated RT. Tumor organoids showed reduced growth rates of 3.2x and 1.8x when treated with 4 and 6 Gy fractionated RT, respectively. Interestingly, combination of 100 µM of 3BP + 4 Gy of RT showed pronounced growth inhibition as compared to 3-BP alone or 4 Gy of radiation alone. Further, positive identification of SOX2, SOX10 and TGFβ indicated presence of cancer stem cells in tumor organoids which might have some role in resistance to therapies in pancreatic cancer.

Conclusions

PTOs produced a similar microenvironment and exhibited similar growth characteristics as in vivo tumors following treatment, indicating their potential for predicting in vivo tumor sensitivity and response to RT and combined chemo-RT treatments.

Proton Arc Therapy vs Interstitial HDR Brachytherapy in Gynecologic Cancer with Parametrial/pelvic Side Wall Extension

Purpose

To investigate whether volumetric-modulated proton arc therapy (VPAT) plans generate comparable doses to organs at risk (OARs) compared with interstitial high–dose-rate (iHDR) brachytherapy for patients with gynecologic cancer with disease extension to parametrial/pelvic side wall, who are not eligible for the aggressive procedure.

Materials and Methods

VPAT delivers proton arc beams by modulated energies at the beam nozzle while maintaining the same incident energy to the gantry during the arc rotation. Plans of 10 patients previously treated with iHDR brachytherapy for high-risk clinical treatment volumes (HRCTV; 31.8–110.6 cm³; lateral dimensions, 4.2–5.6 cm) were selected and compared with VPAT plans. VPAT plans for each patient were designed using a 152- to 245-MeV range of energy-modulated proton beams.

Results

HRCTV coverage of the VPAT plans was comparable to that of the iHDR plans, with V150% showing no statistical differences. On average, the V100% and V90% of VPAT plans were higher than those of the iHDR plans, 95.0% vs 91.9% (P = .02) and 98.6% vs 97.5% (P = .02), respectively. D100 was also 17% higher for the VPAT plans (P = .03). On average, the D_2cm³ of bladder, rectum, and small bowels in the VPAT plans were considerably lower than those in iHDR plans (by 17.4%, 35.2%, and 65.6%, respectively; P < .05 for all OARs).

Conclusion

VPAT–generated plans were dosimetrically superior to those with HDR brachytherapy with interstitial needles for locally advanced gynecologic cancer with parametrial/pelvic side wall disease extension. Dosimetrically, VPAT provides a noninvasive alternative to iHDR brachytherapy with a superior dosimetric profile.

Toward automation of initial chart check for photon/electron EBRT: the clinical implementation of new AAPM task group reports and automation techniques

Purpose

The recently published AAPM TG‐275 and the public review version of TG‐315 list new recommendations for comprehensive and minimum physics initial chart checks, respectively. This article addresses the potential development and benefit of initial chart check automation when these recommendations are implemented for clinical photon/electron EBRT.

Methods

Eight board‐certified physicists with 2–20 years of clinical experience performed initial chart checks using checklists from TG‐275 and TG‐315. Manual check times were estimated for three types of plans (IMRT/VMAT, 3D, and 2D) and for prostate, whole pelvis, lung, breast, head and neck, and brain cancers. An expert development team of three physicists re‐evaluated the automation feasibility of TG‐275 checklist based on their experience of developing and implementing the in‐house and the commercial automation tools in our institution. Three levels of initial chart check automation were simulated: (1) Auto_UMMS_tool (which consists of in‐house program and commercially available software); (2) Auto_TG275 (with full and partial automation as indicated in TG‐275); and (3) Auto_UMMS_exp (with full and partial automation as determined by our experts’ re‐evaluation).

Results

With no automation of initial chart checks, the ranges of manual check times were 29–56 min (full TG‐315 list) and 102–163 min (full TG‐275 list), which varied significantly with physicists but varied little at different tumor sites. The 69 of 71 checks which were considered as “not fully automated” in TG‐275 were re‐evaluated with more automation feasibility. Compared to no automation, the higher levels of automation yielded a great reduction in both manual check times (by 44%–98%) and potentially residual detectable errors (by 15–85%).

Conclusion

The initial chart check automation greatly improves the practicality and efficiency of implementing the new TG recommendations. Revisiting the TG reports with new technology/practice updates may help develop and utilize more automation clinically.

Improving TBI lung dose calculations: Can the treatment planning system help?

Lung toxicity is a serious concern during total body irradiation (TBI). Therefore, evaluation of accurate dose calculation when using lung blocks is of utmost importance. Existing clinical treatment planning systems can perform the calculation but there are large inaccuracies when calculating volumetric dose at extended distances in the presence of high atomic number materials. Percent depth dose and absolute dose measurements acquired at 400 cm SSD with a cerrobend block were compared with calculated values from the Eclipse treatment planning system using AAA and Acuros. The block was simulated in 2 ways; (1) manually drawing a contour to mimic the block and (2) creating a virtual block in the accessory tray. Although the relative dose distribution was accurately calculated, larger deviations of around 50% and 40% were observed between measured depth dose and absolute dose with AAA and Acuros, respectively. Deviations were reduced by optimizing the relative electron density in the contoured block or the transmission factor in the virtual block.

Immune checkpoint inhibition in patients treated with stereotactic radiation for brain metastases

Purpose

Stereotactic radiation therapy (SRT) and immune checkpoint inhibitors (ICI) may act synergistically to improve treatment outcomes but may also increase the risk of symptomatic radiation necrosis (RN). The objective of this study was to compare outcomes for patients undergoing SRT with and without concurrent ICI.

Methods and materials

Patients treated for BMs with single or multi-fraction SRT were retrospectively reviewed. Concurrent ICI with SRT (SRT-ICI) was defined as administration within 3 months of SRT. Local control (LC), radiation necrosis (RN) risk and distant brain failure (DBF) were estimated by the Kaplan-Meier method and compared between groups using the log-rank test. Wilcoxon rank sum and Chi-square tests were used to compare covariates. Multivariate cox regression analysis (MVA) was performed.

Results

One hundred seventy-nine patients treated with SRT for 385 brain lesions were included; 36 patients with 99 lesions received SRT-ICI. Median follow up was 10.3 months (SRT alone) and 7.7 months (SRT- ICI) (p = 0.08). Lesions treated with SRT-ICI were more commonly squamous histology (17% vs 8%) melanoma (20% vs 2%) or renal cell carcinoma (8% vs 6%), (p < 0.001). Non-small cell lung cancer (NSCLC) compromised 60% of patients receiving ICI (n = 59). Lesions treated with SRT-ICI had significantly improved 1-year local control compared to SRT alone (98 and 89.5%, respectively (p = 0.0078). On subset analysis of NSCLC patients alone, ICI was also associated with improved 1 year local control (100% vs. 90.1%) (p = 0.018). On MVA, only tumor size ≤2 cm was significantly associated with LC (HR 0.38, p = 0.02), whereas the HR for concurrent ICI with SRS was 0.26 (p = 0.08). One year DBF (41% vs. 53%; p = 0.21), OS (58% vs. 56%; p = 0.79) and RN incidence (7% vs. 4%; p = 0.25) were similar for SRT alone versus SRT-ICI, for the population as a whole and those patients with NSCLC.

Conclusion

These results suggest SRT-ICI may improve local control of brain metastases and is not associated with an increased risk of symptomatic radiation necrosis in a cohort of predominantly NSCLC patients. Larger, prospective studies are necessary to validate these findings and better elucidate the impact of SRT-ICI on other disease outcomes.

Immunotherapies and Combination Strategies for Immuno-Oncology

The advent of novel immunotherapies in the treatment of cancers has dramatically changed the landscape of the oncology field. Recent developments in checkpoint inhibition therapies, tumor-infiltrating lymphocyte therapies, chimeric antigen receptor T cell therapies, and cancer vaccines have shown immense promise for significant advancements in cancer treatments. Immunotherapies act on distinct steps of immune response to augment the body's natural ability to recognize, target, and destroy cancerous cells. Combination treatments with immunotherapies and other modalities intend to activate immune response, decrease immunosuppression, and target signaling and resistance pathways to offer a more durable, long-lasting treatment compared to traditional therapies and immunotherapies as monotherapies for cancers. This review aims to briefly describe the rationale, mechanisms of action, and clinical efficacy of common immunotherapies and highlight promising combination strategies currently approved or under clinical development. Additionally, we will discuss the benefits and limitations of these immunotherapy approaches as monotherapies as well as in combination with other treatments.

A multi-center analysis of single-fraction versus hypofractionated stereotactic radiosurgery for the treatment of brain metastasis

Background

Hypofractionated-SRS (HF-SRS) may allow for improved local control and a reduced risk of radiation necrosis compared to single-fraction-SRS (SF-SRS). However, data comparing these two treatment approaches are limited. The purpose of this study was to compare clinical outcomes between SF-SRS versus HF-SRS across our multi-center academic network.

Methods

Patients treated with SF-SRS or HF-SRS for brain metastasis from 2013 to 2018 across 5 radiation oncology centers were retrospectively reviewed. SF-SRS dosing was standardized, whereas HF-SRS dosing regimens were variable. The co-primary endpoints of local control and radiation necrosis were estimated using the Kaplan Meier method. Multivariate analysis using Cox proportional hazards modeling was performed to evaluate the impact of select independent variables on the outcomes of interest. Propensity score adjustments were used to reduce the effects confounding variables. To assess dose response for HF-SRS, Biologic Effective Dose (BED) assuming an α/β of 10 (BED₁₀) was used as a surrogate for total dose.

Results

One-hundred and fifty six patients with 335 brain metastasis treated with SF-SRS (n = 222 lesions) or HF-SRS (n = 113 lesions) were included. Prior whole brain radiation was given in 33% (n = 74) and 34% (n = 38) of lesions treated with SF-SRS and HF-SRS, respectively (p = 0.30). After a median follow up time of 12 months in each cohort, the adjusted 1-year rate of local control and incidence of radiation necrosis was 91% (95% CI 86–96%) and 85% (95% CI 75–95%) (p = 0.26) and 10% (95% CI 5–15%) and 7% (95% CI 0.1–14%) (p = 0.73) for SF-SRS and HF-SRS, respectively. For lesions > 2 cm, the adjusted 1 year local control was 97% (95% CI 84–100%) for SF-SRS and 64% (95% CI 43–85%) for HF-SRS (p = 0.06). On multivariate analysis, SRS fractionation was not associated with local control and only size ≤2 cm was associated with a decreased risk of developing radiation necrosis (HR 0.21; 95% CI 0.07–0.58, p < 0.01). For HF-SRS, 1 year local control was 100% for lesions treated with a BED₁₀ ≥ 50 compared to 77% (95% CI 65–88%) for lesions that received a BED₁₀ < 50 (p = 0.09).

Conclusions

In this comparison study of dose fractionation for the treatment of brain metastases, there was no difference in local control or radiation necrosis between HF-SRS and SF-SRS. For HF-SRS, a BED₁₀ ≥ 50 may improve local control.

Colorectal Cancer and Probiotics: Are Bugs Really Drugs?

Colorectal cancer (CRC) is one of the most common types of cancer worldwide. There are many factors that predispose a patient to the disease such as age, family history, ethnicity, and lifestyle. There are different genetic factors and diseases that also increase a person’s risk for developing CRC. Studies have found associations between gut microbiome and the risk for developing versus protection against CRC. Normal gut microbiome aid in daily functions of the human body such as absorption, metabolism, detoxification, and regulation of inflammation. While some species of bacteria prevent CRC development and aid in therapeutic responses to various treatment regiments, other species seem to promote CRC pathogenesis. In this regard, many studies have been conducted to not only understand the biology behind these opposing different bacterial species; but also to determine if supplementation of these tumor opposing bacterial species as probiotics lends toward decreased risk of CRC development and improved therapeutic responses in patients with CRC. In this literature review, we aim to discuss the basics on colorectal cancer (epidemiology, risk factors, targets, treatments), discuss associations between different bacterial strains and CRC, and discuss probiotics and their roles in CRC prevention and treatment.

Novel Delivery Systems for Checkpoint Inhibitors

Checkpoint inhibition (CPI) therapies have been proven to be powerful clinical tools in treating cancers. FDA approvals and ongoing clinical development of checkpoint inhibitors for treatment of various cancers highlight the immense potential of checkpoint inhibitors as anti-cancer therapeutics. The occurrence of immune-related adverse events, however, is a major hindrance to the efficacy and use of checkpoint inhibitors as systemic therapies in a wide range of patients. Hence, methods of sustained and tumor-targeted delivery of checkpoint inhibitors are likely to improve efficacy while also decreasing toxic side effects. In this review, we summarize the findings of the studies that evaluated methods of tumor-targeted delivery of checkpoint inhibitors, review their strengths and weaknesses, and discuss the outlook for therapeutic use of these delivery methods.

Checkpoint Inhibition: Will Combination with Radiotherapy and Nanoparticle-Mediated Delivery Improve Efficacy?

Checkpoint inhibition (CPI) has been a rare success story in the field of cancer immunotherapy. Knowledge gleaned from preclinical studies and patients that do not respond to these therapies suggest that the presence of tumor-infiltrating lymphocytes and establishment of immunostimulatory conditions, prior to CPI treatment, are required for efficacy of CPI. To this end, radiation therapy (RT) has been shown to promote immunogenic cell-death-mediated tumor-antigen release, increase infiltration and cross-priming of T cells, and decreasing immunosuppressive milieu in the tumor microenvironment, hence allowing CPI to take effect. Preclinical and clinical studies evaluating the combination of RT with CPI have been shown to overcome the resistance to either therapy alone. Additionally, nanoparticle and liposome-mediated delivery of checkpoint inhibitors has been shown to overcome toxicities and improve therapeutic efficacy, providing a rationale for clinical investigations of nanoparticle, microparticle, and liposomal delivery of checkpoint inhibitors. In this review, we summarize the preclinical and clinical studies of combined RT and CPI therapies in various cancers, and review findings from studies that evaluated nanoparticle and liposomal delivery of checkpoint inhibitors for cancer treatments.

Liposomes: Clinical Applications and Potential for Image-Guided Drug Delivery

Liposomes have been extensively studied and are used in the treatment of several diseases. Liposomes improve the therapeutic efficacy by enhancing drug absorption while avoiding or minimizing rapid degradation and side effects, prolonging the biological half-life and reducing toxicity. The unique feature of liposomes is that they are biocompatible and biodegradable lipids, and are inert and non-immunogenic. Liposomes can compartmentalize and solubilize both hydrophilic and hydrophobic materials. All these properties of liposomes and their flexibility for surface modification to add targeting moieties make liposomes more attractive candidates for use as drug delivery vehicles. There are many novel liposomal formulations that are in various stages of development, to enhance therapeutic effectiveness of new and established drugs that are in preclinical and clinical trials. Recent developments in multimodality imaging to better diagnose disease and monitor treatments embarked on using liposomes as diagnostic tool. Conjugating liposomes with different labeling probes enables precise localization of these liposomal formulations using various modalities such as PET, SPECT, and MRI. In this review, we will briefly review the clinical applications of liposomal formulation and their potential imaging properties.

18F-Labeled Carboplatin Derivative for PET Imaging of Platinum Drug Distribution

Increasing evidence indicates that reduced intracellular drug accumulation is the parameter most consistently associated with platinum drug resistance, emphasizing the need to directly measure the intratumor drug concentration. In the era of precision medicine and with the advent of powerful imaging and proteomics technologies, there is an opportunity to better understand drug resistance by exploiting these techniques to provide new knowledge on drug-target interactions. Here, we contribute to this endeavor by reporting on the development of an 18F-labeled carboplatin derivative (18F-FCP) that has the potential to image drug uptake and retention, including intratumoral distribution, by PET. Methods: Fluorinated carboplatin (19F-FCP) was synthesized using 19F-labeled 2-(5-fluoro-pentyl)-2-methyl malonic acid (19F-FPMA) as the labeling agent to coordinate with the cisplatin-aqua complex. It was then used to treat cell lines and compared with cisplatin and carboplatin at different concentrations. Manual radiosynthesis and characterization of 18F-FCP were performed using 18F-FPMA for coordination with the cisplatin-aqua complex. Automated radiosynthesis of 18F-FCP was optimized on the basis of manual synthesis procedures. The stability of 18F-FCP was verified using high-performance liquid chromatography. 18F-FCP was evaluated using ex vivo biodistribution and in vivo PET imaging in non-tumor-bearing animals as well as in KB-3-1 and COLO-205 tumor xenograft-bearing nude mice. Results: In vitro cytotoxicity studies demonstrated that 19F-FCP has an antitumor activity profile similar to that of the parent drug carboplatin. In vivo plasma and urine stability analysis showed intact 18F-FCP at 24 h after injection. PET imaging and biodistribution studies showed fast clearance from blood and major accumulation in the kidneys, indicating substantial renal clearance of 18F-FCP. Using 18F-FCP PET, we could image and identify the intratumor drug profile. Conclusion: Our results demonstrated that 19F-FCP, like carboplatin, retains antitumor activity in various cell lines. 18F-FCP could be a useful imaging tool for measuring the intratumor drug distribution. This strategy of using a new therapeutic carboplatin derivative to quantify and track platinum drugs in tumors using PET has the potential to translate into a clinically useful imaging tool for individual patients.

Ethnic heterogeneity and prostate cancer mortality in Hispanic/Latino men: a population-based study

BACKGROUND

Few studies focus on prostate cancer (PCa) outcomes in Hispanic/Latino men. Our study explores whether Hispanic/Latino subgroups demonstrate significantly different prostate cancer-specific mortality (PCSM) relative to Non-Hispanic White (NHW) and Non-Hispanic Black (NHB) men.

METHODS

We extracted a population-based cohort of men diagnosed with local-regional PCa from 2000-2013 (n= 486,865). PCSM was measured in racial/ethnic groups: NHW (n=352,886), NHB (n= 70,983), Hispanic/Latino (n= 40,462), and Asian American/Pacific Islander (n= 22,534). PCSM was also measured in Hispanic/Latino subgroups: Mexican (n= 8,077), Puerto Rican (n= 1,284), South or Central American (n= 3,021), Cuban (n= 788), and Dominican (n= 300). We conducted univariable and multivariable analyses (MVA) to compare risk for PCSM.

RESULTS

Compared to NHW men, results showed worse outcomes for NHB men with similar outcomes for Hispanic/Latino men. In MVA with NHW men as a reference, NHB (HR= 1.15, p <0.001) men had significantly worse PCSM and Hispanic/Latino (HR= 1.02, p= 0.534) men did not show a significant difference. In a second MVA, Puerto Rican (HR= 1.71, p <0.001) and Mexican (HR= 1.21, p= 0.008) men had significantly higher PCSM. With NHB men as a reference, the MVA showed Puerto Rican (HR= 1.50, p= 0.006) men with higher PCSM and Mexican (HR= 1.08, p= 0.307) men with no significant difference.

CONCLUSIONS

Our findings indicate previously unknown disparities in PCSM for Puerto Rican and Mexican American men.

Intramedullary Nailing System in Unstable Both Bone Diaphyseal Fractures in Children

Background Forearm fractures in pediatric population is usually managed conservatively. Unstable fractures need operative intervention like closed or open intramedullary nailing or open reduction and internal fixation with plates and screws. However, there is no consensus regarding the method of treatment according to age group. Objective To standardize the use of elastic nailing system as effective form of treatment in terms of function, cost and lower complications as compared to widely used titanium nails in developed countries.Method Sixty eight pediatric patients with both bone forearm diaphyseal fractures were managed with closed reduction and intramedullary fixation with rush nail or k-wire and followed at least for 6 months for evaluation of radiological and functional outcome. Result Patients were divided into two age groups, Group A for age of 5 to 9 years (26 patients) and Group B for age of 10-15 years (42 patients). The mean time for union for Group A patient was 7.31 weeks which was significantly lower than that of Group B patients of 9.33 weeks (p-value < 0.05). All the patients in Group A had excellent outcome and 36 (85.7%) patients had excellent outcome and 6 (14.3%) had good outcome in Group B. 5 out of 68 cases (7.35 %) had minor complications (2 in Group A and 3 in Group B). The mean time for implant removal was 17.9 weeks in Group A and 22.9 in Group B. Conclusion Intramedullary fixation for unstable diaphyseal both bone fractures of forearm is safe and cost effective method of treatment with good to excellent functional outcome with union time being significantly lower in younger age group.

[18F]-Fluorinated Carboplatin and [111In]-Liposome for Image-Guided Drug Delivery

Radiolabeled liposomes have been employed as diagnostic tools to monitor in vivo distribution of liposomes in real-time, which helps in optimizing the therapeutic efficacy of the liposomal drug delivery. This work utilizes the platform of [111In]-Liposome as a drug delivery vehicle, encapsulating a novel 18F-labeled carboplatin drug derivative ([18F]-FCP) as a dual-molecular imaging tool as both a radiolabeled drug and radiolabeled carrier. The approach has the potential for clinical translation in individual patients using a dual modal approach of clinically-relevant radionuclides of 18F positron emission tomography (PET) and 111In single photon emission computed tomography (SPECT). [111In]-Liposome was synthesized and evaluated in vivo by biodistribution and SPECT imaging. The [18F]-FCP encapsulated [111In]-Liposome nano-construct was investigated, in vivo, using an optimized dual-tracer PET and SPECT imaging in a nude mouse. The biodistribution data and SPECT imaging showed spleen and liver uptake of [111In]-Liposome and the subsequent clearance of activity with time. Dual-modality imaging of [18F]-FCP encapsulated [111In]-Liposome showed significant uptake in liver and spleen in both PET and SPECT images. Qualitative analysis of SPECT images and quantitative analysis of PET images showed the same pattern of activity during the imaging period and demonstrated the feasibility of dual-tracer imaging of a single dual-labeled nano-construct.

Quantitative imaging: Correlating image features with the segmentation accuracy of PET based tumor contours in the lung

The purpose of this study was to investigate the correlation between image features extracted from PET images and the accuracy of manually drawn lesion contours in the lung. Such correlations are interesting in that they could potentially be used in predictive models to help guide physician contouring. In this work, 26 synthetic PET datasets were created using an anthropomorphic phantom and Monte Carlo simulation. Manual contours of simulated lesions were provided by 10 physicians. Contour accuracy was quantified using five commonly used similarity metrics which were then correlated with several features extracted from the images. Features were sub-divided into three groups using intensity, geometry, and texture as categorical descriptors. When averaged among the participants, the results showed relatively strong correlations with complexity and contrast_I (r≥0.65, p<0.001), and moderate correlations with several other image features (r≥0.5, p<0.01). The predictive nature of these correlations was improved through stepwise regression and the creation of multi-feature models. Imaging features were also correlated with the standard deviation of contouring error in order to investigate inter-observer variability. Several features were consistently identified as influential including integral of mean curvature and complexity. These relationships further the understanding as to what causes variation in the contouring of PET positive lesions.

Abstract PR04: Ethnic heterogeneity and prostate cancer mortality in Hispanic/Latino men

Purpose: Few studies have focused on the rapidly growing and extremely diverse Hispanic/Latino population in regards to prostate cancer outcomes. Our study explores whether heterogeneity between Hispanic/Latino men of diverse ancestry potentially contributes to unexplored disparities in five-year prostate cancer-specific mortality and all-cause mortality.

Patients and Methods: From the Surveillance, Epidemiology, and End Results program (SEER), we designed a population-based cohort of men diagnosed with local-regional prostate cancer (n= 432,356) from 2000-2012. Five-year cumulative incidence of prostate cancer-specific mortality was obtained using competing risks analysis and all-cause mortality was determined by using one minus the Kaplan-Meier survival estimate of overall survival. This was examined for different racial and/or ethnic groups: Non-Hispanic White (n= 313,514), Non-Hispanic Black (n= 62,346), Hispanic/Latino (n= 36,407), and Asian American/Pacific Islander (n= 20,089). We also measured prostate cancer-specific and all-cause mortalities in Hispanic/Latino subgroups: Mexican (n= 7,273), Puerto Rican (n= 1,174), South or Central American (n= 2,666), Cuban (n= 747), and Dominican (n= 292).

Results: In all racial/ethnic groups, five-year cumulative incidence rates were highest for Non-Hispanic Black men at 15.96% (95% CI: 15.6 - 16.3) and were lowest in Hispanic/Latino men at 13.08% (95% CI: 12.6 - 13.5) and Asian American/Pacific Islander men at 13.33% (95% CI: 12.7 - 13.9). Within ethnic subgroups, Puerto Rican men at 22.06% (95% CI: 19.4 - 25.1) and Cuban men 20.91% (95% CI: 17.8 - 24.5) showed significantly higher five-year all-cause mortality than all other groups. Mexican men showed the third highest rate of all groups with 16.47% (95% CI: 15.4 - 17.6). For five-year prostate cancer-specific mortality, both Non-Hispanic Black and Hispanic/Latino men showed similar rates that were higher than other racial/ethnic groups with 3.39% (95% CI: 3.22 - 3.57) and 3.29% (95% CI: 3.07 - 3.52), respectively. For ethnic subgroups, Puerto Rican men at 5.26% (95% CI: 3.88 - 6.92) and Mexican men at 4.77% (95% CI: 4.19 - 5.40) showed significantly higher five-year prostate cancer-specific mortality than all other groups. Cuban and Dominican men showed high rates of both five-year all-cause and prostate cancer-specific mortality, but without significance.

Conclusions: Our findings indicate previously unknown disparities in five-year prostate cancer-specific mortality in Mexican and Puerto Rican men. We also note the increased all-cause mortality within Puerto Rican men diagnosed with prostate cancer, of which may be influenced by comorbid disease. These findings should be further explored and considered in screening and management guidelines.

Citation Format: Felix M. Chinea, Vivek N. Patel, Deukwoo Kwon, Chris J. Lopez, Narottam Lamichhane, Sanoj Punnen, Erin Kobetz, Matthew C. Abramowitz, Alan Pollack. Ethnic heterogeneity and prostate cancer mortality in Hispanic/Latino men. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr PR04.

Safety and Efficacy of Spinal Anaesthesia in Percutaneous Nephrolithotomy

INTRODUCTION

Renal stone is one of the common entities occurring in our population. There are different treatment modalities of stones; out of those percutaneous nephrolithotomy is one of the most popular and effective for the renal and upper tract stones. This study is based to compare the safety and efficacy of spinal anaesthesia and general anaesthesia in PCNL.

METHODS

In a randomized prospective study 60 patients were divided in two groups; group 1 (n=30) underwent PCNL in general anaesthesia and group 2 (n=30) underwent PCNL in spinal anaesthesia in prone position with the conventional technique. Demographic, operative data, post operative complications, patients' satisfaction rate and follow up complications were recorded and analyzed between two groups.

RESULTS

Mean age in group 1 was 39.10±12.45years and 36.10±14.18 in group 2 (P=0.100). Mean stone size in group 1 was 3.75±1.27cm and 3.23±1.36cm in group 2 (P=0.129).Similarly the operative time was 89.10 ± 49.38 min and 62.53±35.91 min in group 1 and group 2 respectively (P=0.042). There was no significant difference between the complications regarding the anaesthesia. Post operative nausea and vomiting were significantly higher in group 1 and headache in group 2 (p=<0.001). Overall patient satisfaction rate was higher in group 2 then in group 1 (p=0.01). Hospital stay in group 1 was 5.27±1.87 days and 4.53±1.88 days in group 2 (p = 0.07). Stone success rate was similar in each group (p =0.50).

CONCLUSIONS

Spinal anaesthesia is a safe and effective method in performing PCNL.

Going the distance: validation of Acuros and AAA at an extended SSD of 400 cm

Accurate dose calculation and treatment delivery is essential for total body irradiation (TBI). In an effort to verify the accuracy of TBI dose calculation at our institution, we evaluated both the Varian Eclipse AAA and Acuros algorithms to predict dose distributions at an extended source‐to‐surface distance (SSD) of 400 cm. Measurements were compared to calculated values for a 6 MV beam in physical and virtual phantoms at 400 cm SSD using open beams for both 5×5 and 40×40 cm2 field sizes. Inline and crossline profiles were acquired at equivalent depths of 5 cm, 10 cm, and 20 cm. Depth‐dose curves were acquired using EBT2 film and an ion chamber for both field sizes. Finally, a RANDO phantom was used to simulate an actual TBI treatment. At this extended SSD, care must be taken using the planning system as there is good relative agreement between measured and calculated profiles for both algorithms, but there are deviations in terms of the absolute dose. Acuros has better agreement than AAA in the penumbra region.

PACS number(s): 87.55.kd

Intrinsically radiolabelled [(59)Fe]-SPIONs for dual MRI/radionuclide detection

Towards the development of iron oxide nanoparticles with intrinsically incorporated radionuclides for dual Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) and more recently of Single Photon Emission Computed Tomography/Magnetic Resonance Imaging (SPECT/MRI), we have developed intrinsically radiolabeled [(59)Fe]-superparamagnetic iron oxide nanoparticles ([(59)Fe]-SPIONs) as a proof of concept for an intrinsic dual probe strategy. (59)Fe was incorporated into Fe3O4 nanoparticle crystal lattice with 92±3% efficiency in thermal decomposition synthesis. Multidentate poly(acrylic acid)-dopamine-poly(ethylene-glycol-2000) (PAA-DOP-PEG) ligands were designed and synthesized based on facile EDC chemistry and utilized to functionalize the [(59)Fe]-SPIONs. The transverse relaxivity of [(59)Fe]-SPIONs (97±3 s(-1)mM(-1)) was characterized and found to be similar to non-radioactive SPIONs (72±10 s(-1)mM(-1)), indicating that (59)Fe incorporation does not alter the SPIONs' MRI contrast properties. [(59)Fe]-SPIONs were used to evaluate the nanoparticle biodistribution by ex vivo gamma counting and MRI. Nude mice (n=15) were injected with [(59)Fe]-SPIONs and imaged at various time points with 7T small animal MRI scanner. Ex vivo biodistribution was evaluated by tissue-based gamma counting. MRI signal contrast qualitatively correlates with the %ID/g of [(59)Fe]-SPIONs, with high contrast in liver (45±6%), medium contrast in kidneys (21±5%), and low contrast in brain (4±6%) at 24 hours. This work demonstrates the synthesis and in vivo application of intrinsically radiolabeled [(59)Fe]-SPIONs for bimodal detection and provides a proof of concept for incorporation of both gamma- and positron-emitting inorganic radionuclides into the core of metal based MRI contrast agent nanoparticles.

Highly stable intrinsically radiolabeled indium-111 quantum dots with multidentate zwitterionic surface coating: dual modality tool for biological imaging

A highly stable bimodal indium(111) radiolabeled indium QDs were synthesized for in vivo SPECT/fluorescence imaging.

Retroperitoneal pararenal castleman’s disease: a case report

Castleman’s diseas is a rare lymphoproliferative disorder of unknown etiology. We report a 28 years old woman with solitary Castleman’s disease in the left pararenal space. This case was diagnosed preoperatively as renal cell carcinoma. The patient underwent a radical nephrectomy with dissection of pararenal mass. Histopathological examination of the surgically resected specimen showed the hyaline vascular type of Castleman’s disease. A preoperative diagnosis of Castleman’s disease is difficult; therefore, a surgical resection and histopathological evaluation can provide an accurate diagnosis of tumor. Taking this case into consideration, we suggest that Castleman’s disease should be included in the differential diagnosis of renal tumors. DOI: http://dx.doi.org/10.3126/jpn.v3i6.9004 Journal of Pathology of Nepal (2013) Vol. 3, 509-511

Transurethral resection of prostate – a five year experience in College of Medical Sciences and Teaching Hospital,Bharatpur, Nepal

Aims Transurethral resection of prostate(TURP) is still considered gold standard for the management of benign prostatic hyperplasia(BPH) and it has become the need of every urology center today. The purpose of this study is to report a five years experience and results in the management of BPH by TURP. Materials and methods Retrospective analysis of 330 cases of TURP done by single surgeon between January 2007 and December 2011 in urology unit, College of Medical Sciences, Bharatpur, Nepal was carried out. Results Mean age and duration of symptoms was 64.88±3.904 years and 30.7 months respectively , mean size of prostate was 48.33±15.214 grams, mean IPSS before surgery was 27.88±3.493 and after 1 year follow up of 262 cases it was 9.71±3.820. . Mean duration of post operative per urethral catheterization, bladder irrigation with normal saline and total duration of hospital stay was 2.82±0.622, 28.16± 8.895and 3.82±0.622 days respectively. Mean operating time was 40.53±12.949 minutes. 7(2.12%) patients developed intraperitoneal fluid extravasation, 8(2.42%) cases developed clot retention. 2(0.67%) cases re-admitted one week after discharge with clot retention and UTI. 3(0.9%)cases presented two years after surgery with bladder neck contracture. No case of TUR syndrome was seen and there was no mortality. Conclusion Most of the patients presents late with marked obstructive symptoms and large prostate glands in this part of Nepal. The urinary symptoms in patients with BPH significantly improved after TURP and those patients having severe symptoms gained the most. The complication rates following TURP decreases as experience grow and after a experience of 50 TURP they are almost none. So 50 TURP can be set as benchmark for the beginners. It was also noticed that resection volume of the prostate increased and the resection time decreased significantly after 50 case of TURP. Journal of College of Medical Sciences-Nepal, 2012, Vol-8, No-4, 16-21 DOI: http://dx.doi.org/10.3126/jcmsn.v8i4.8695

Abstract 4532: Fluorine-18- carboplatin derivative for imaging and therapeutic applications

DNA-damaging agents, such as cisplatin and other platinum drugs are the largest class of anti-cancer drugs. They are most important in the clinical use for the treatment of various cancers, although ovarian cancer cells often become resistant. Besides resistance, non-specific uptake in normal tissues and related toxicity is a dose limiting factor and affects their overall effectiveness. Knowledge of the drug concentration in the tumor as well as its overall concentration in the body of a patient will be helpful in accurately predicting the overall responsiveness of a patient to the drug. This type of knowledge can be accomplished by the development of a drug analog with positron emission tomography (PET) imaging capability, so that the accumulation of the drug in the tumor and normal organs can be tracked and quantified during the course of therapy to predict its effectiveness in a patient. Therefore, we developed a novel fluorinated carboplatin derivative, towards a hybrid agent for imaging and therapy. We synthesized 19F fluorinated carboplatin derivative using 2-(5-fluoro-pentyl)-2-methyl malonic acid by co-ordination with cis-platinum aqua complex. It was then used to treat various cell lines and compared with Cis-platin and Carboplatin at different concentrations ranging from 0.001 μM to 100 μM for 72 hrs and 96 hrs. LC50 values calculated from cell viability indicate that fluorinated carboplatin is a more potent drug than Carboplatin but less effective than Cisplatin.

Table 1: LC50 values of fluorinated carboplatin and known platinum drugs Cell line Cisplatin (μM) Carboplatin(μM) Fluorinated Carboplatin (μM) 72 hrs 96 hrs 72 hrs 96 hrs 72 hrs 96 hrs COLO 205 28.78 1.35 &gt;100 48.98 92.52 31.56 SK-OV-3 4.34 1.28 33.7 18.94 20.3 12.56 FaDu 2.77 &lt;2 34.72 11.26 21.54 8.55 A549 11.01 3.07 56.56 31.78 41.18 24.8 A498 13.35 3.42 152.83 39.34 57.25 18.5 LNCaP 19.2 7.18 113.51 63.4 80.09 46.06 RWPE-1 6.27 &lt;1 65.19 36.8 34.69 10.2 KB 3-1 4.13 2.04 59.82 26.08 22.76 13.46

We have also developed a microfluidic method to synthesize [18F]-2-(5-fluoro-pentyl)-2-methyl malonic acid, which will co-ordinate with cis-platinum aqua complex to yield 18F labeled carboplatin derivative. Our approach to synthesis various derivatives of 18F labeled fluorinated carboplatin will allow us to develop anticancer drugs with PET imaging capabilities.

Citation Format: Gajanan K. Dewkar, Purnima Jose, Narottam Lamichhane, Celina Thadigiri, Gobalakrishnan Sundaresan, Nicholas Farrell, Jamal Zweit. Fluorine-18- carboplatin derivative for imaging and therapeutic applications. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4532. doi:10.1158/1538-7445.AM2013-4532