Survival Advantage Following TAG-72 Antigen-Directed Cancer Surgery in Patients With Colorectal Carcinoma: Proposed Mechanisms of Action

Patients with colorectal carcinoma (CRC) continue to have variable clinical outcomes despite undergoing the same surgical procedure with curative intent and having the same pathologic and clinical stage. This problem suggests the need for better techniques to assess the extent of disease during surgery. We began to address this problem 35 years ago by injecting patients with either primary or recurrent CRC with 125I-labeled murine monoclonal antibodies against the tumor-associated glycoprotein-72 (TAG-72) and using a handheld gamma-detecting probe (HGDP) for intraoperative detection and removal of radioactive, i.e., TAG-72-positive, tissue. Data from these studies demonstrated a significant difference in overall survival data (p < 0.005 or better) when no TAG-72-positive tissue remained compared to when TAG-72-positive tissue remained at the completion of surgery. Recent publications indicate that aberrant glycosylation of mucins and their critical role in suppressing tumor-associated immune response help to explain the cellular mechanisms underlying our results. We propose that monoclonal antibodies to TAG-72 recognize and bind to antigenic epitopes on mucins that suppress the tumor-associated immune response in both the tumor and tumor-draining lymph nodes. Complete surgical removal of all TAG-72-positive tissue serves to reverse the escape phase of immunoediting, allowing a resetting of this response that leads to improved overall survival of the patients with either primary or recurrent CRC. Thus, the status of TAG-72 positivity after resection has a significant impact on patient survival.

Admission to the ICU in the last 30 days of life and systemic anticancer therapy in the last two weeks of life at Lifespan Cancer Institute (LCI)

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Background: The ASCO Quality Oncology Practice Initiative identifies ICU admission in the last 30 days and systemic anticancer therapy in the last 14 days of life as indicators of overly aggressive end-of-life care. We sought to delineate clinical factors associated with these indicators. Methods: An IRB approved retrospective chart review was conducted on patients with solid tumors at LCI who died in timepoints ending in January, July and November of 2016 and 2017. Patients were identified through our tumor registry. Patients’ medical records were reviewed for cancer stage, care received, palliative care contact, site of death, ICU admission in last 30 days, and receipt of systemic anticancer therapy (excluding antihormonal therapy) in last 6 months and 2 weeks of life. Results: A total of 250 patients were included in our analysis. 18.8% of LCI patients were admitted to the ICU in the last 30 days of life, 12.8% received systemic anticancer therapy in the last 2 weeks of life, and 19.2% experienced death in the hospital. Significant factors associated with an ICU admission in the last 30 days of life were a diagnosis of lymphoma compared to breast, gynecologic, gastrointestinal, lung, genitourinary, melanoma/carcinoma of unknown primary/head and neck cancer, or other (42.9% vs 20% vs 14.3% vs 9% vs 23.1% vs 25% vs 0% vs 26.3%; P = 0.01), systemic anticancer therapy in last 2 weeks of life (40.6% vs 16.1%; P < 0.005), and age ≤ 45 years at time of metastatic disease compared to age 46-65 or age ≥ 66 (50% vs 15.9% vs 18.1%; P < 0.05). A significant factor associated with systemic anticancer therapy in the last 2 weeks of life was age ≤ 45 years at time of metastatic disease compared to age 46-65 or age ≥ 66 (35.7% vs 16.9% vs 9.4%; P < 0.05). Lastly, a significant factor associated with death in the hospital was lack of palliative care team contact (28.9% vs 15%; P < 0.05). Conclusions: Understanding factors associated with intensive care at the end of life is critical to the provision of value-based cancer care. In this study, a diagnosis of lymphoma, systemic anticancer treatment in the last 2 weeks of life, and age ≤ 45 years at time of metastatic disease were associated with ICU stays in the last 30 days of life. Age ≤ 45 years at time of metastatic disease was associated with systemic anticancer treatment in the last 2 weeks of life, while lack of palliative care involvement was associated with greater chance of death in the hospital. Further understanding of the complex interplay that governs care and decision making at the end of life is required.

Retrospective chart review to characterize admission to the ICU in the last 30 days of life and use of systemic anticancer therapy in the last two weeks of life at the Lifespan Cancer Institute

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Background: Admission to the ICU in the last 30 days of life and use of systemic anticancer therapy in the last 2 weeks of life are indicators of overly aggressive end-of-life care and have been incorporated into the American Society of Clinical Oncology (ASCO) Quality Oncology Practice Initiative (QOPI) as benchmarks to assess care across cancer centers. We sought to better define the proportion of patients at our institution who met either of these endpoints and to delineate factors that might be associated with them. Methods: A retrospective chart review was conducted on patients with solid tumors, who underwent anticancer therapy at the LCI, and died in timepoints ending in January, July and November of 2017. After IRB approval, patients were identified through our tumor registry. Patients’ electronic medical records were reviewed for past history, cancer stage, type of care received, palliative care contact, site of death, ICU admission in last 30 days of life, receipt of immunotherapy and biologic (precision) therapy in last 6 months of life, and systemic anticancer therapy (excluding antihormonal therapy) in last 2 weeks of life. Results: A total of 134 patients died in this time period; 18 were excluded (leukemia/myeloma) leading to 116 patients for this analysis. Our review showed that 16.4% of LCI patients were admitted to the ICU in the last 30 days of life and 9.5% received systemic anticancer therapy in the last 2 weeks of life. Significant factors associated with an ICU admission in the last 30 days of life were receipt of biologic (precision) therapy in the last 6 months of life (41.7% vs. 13.9%; P<0.05) and never having been married (30.4% vs. 13.3%; P=0.05). Significant factors that were associated with death in the hospital were lack of palliative care team contact (34.3% vs. 13%; P<0.05) and male gender (24.1% vs. 9.1%; P<0.05). Conclusions: Understanding the factors associated with intensive care at the end of life is critical to the provision of value-based cancer care. In this study, the receipt of precision therapy in the last 6 months of life and never having been married were associated with ICU stays in the last 30 days of life, while lack of palliative care involvement and male gender were associated with greater chances of death in the hospital. Further understanding of the complex interplay that governs care and decision making in the end of life is required.

Coaxial projective imaging system for surgical navigation and telementoring

A coaxial projective imaging (CPI) module acquires surgical scene images from the local site of surgery, transfers them wirelessly to the remote site, and projects instructive annotations to the surgical field. At the remote site, the surgical scene images are displayed, and the instructive annotations from a surgical specialist are wirelessly transferred back to the local site in order to guide the surgical intervention by a less experienced surgeon. The CPI module achieves seamless imaging of the surgical field and accurate projection of the instructive annotations, by a coaxial optical path design that couples the imaging arm with the projection arm and by a color correction algorithm that recovers the true color of the surgical scene. Our benchtop study of tele-guided intervention verifies that the proposed system has a positional accuracy of better than 1 mm at a working distance ranging from 300 to 500 mm. Our in vivo study of cricothyrotomy in a rabbit model proves the concept of tele-mentored surgical navigation. This is the first report of tele-guided surgery based on CPI. The proposed technique can be potentially used for surgical training and for telementored surgery in resource-limited settings.

Handheld projective imaging device for near-infrared fluorescence imaging and intraoperative guidance of sentinel lymph node resection

We propose a handheld projective imaging device for orthotopic projection of near-infrared fluorescence images onto target biological tissue at visible wavelengths without any additional visual aid. The device integrates a laser diode light source module, a camera module, a projector, an ultrasonic distance sensor, a Raspberry Pi single-board computer, and a battery module in a rugged handheld unit. It is calibrated at the detected working distance for seamless coregistration between fluorescence emission and projective imaging at the target tissue site. The proposed device is able to achieve a projection resolution higher than 314  μm and a planar projection bias less than 1 mm at a projection field of view of 58  ×  108  mm2 and a working distance of 27 cm. Technical feasibility for projective imaging is verified in an ex vivo model of chicken breast tissue using indocyanine green as a fluorescence agent. Clinical utility for image-guided surgery is demonstrated in a clinical trial where sentinel lymph nodes in breast cancer patients are identified and resected under the guidance of projective imaging. Our ex vivo and in vivo experiments imply the clinical utility of deploying the proposed device for image-guided surgical interventions in resource-limited settings.

Linker engineering in anti-TAG-72 antibody fragments optimizes biophysical properties, serum half-life, and high-specificity tumor imaging

Antibody (Ab) fragments have great clinical potential as cancer therapeutics and diagnostics. Their small size allows for fast clearance from blood, low immunoreactivity, better tumor penetration, and simpler engineering and production. The smallest fragment derived from a full-length IgG that retains binding to its antigen, the single-chain variable fragment (scF_V), is engineered by fusing the variable light and variable heavy domains with a peptide linker. Along with switching the domain orientation, altering the length and amino acid sequence of the linker can significantly affect scF_V binding, stability, quaternary structure, and other biophysical properties. Comprehensive studies of these attributes in a single scaffold have not been reported, making design and optimization of Ab fragments challenging. Here, we constructed libraries of 3E8, an Ab specific to tumor-associated glycoprotein 72 (TAG-72), a mucinous glycoprotein overexpressed in 80% of adenocarcinomas. We cloned, expressed, and characterized scF_Vs, diabodies, and higher-order multimer constructs with varying linker compositions, linker lengths, and domain orientations. These constructs dramatically differed in their oligomeric states and stabilities, not only because of linker and orientation but also related to the purification method. For example, protein L-purified constructs tended to have broader distributions and higher oligomeric states than has been reported previously. From this library, we selected an optimal construct, 3E8.G₄S, for biodistribution and pharmacokinetic studies and in vivo xenograft mouse PET imaging. These studies revealed significant tumor targeting of 3E8.G₄S with a tumor-to-background ratio of 29:1. These analyses validated 3E8.G₄S as a fast, accurate, and specific tumor-imaging agent.

A Wearable Goggle Navigation System for Dual-Mode Optical and Ultrasound Localization of Suspicious Lesions: Validation Studies Using Tissue-Simulating Phantoms and an Ex Vivo Human Breast Tissue Model

Surgical resection remains the primary curative treatment for many early-stage cancers, including breast cancer. The development of intraoperative guidance systems for identifying all sites of disease and improving the likelihood of complete surgical resection is an area of active ongoing research, as this can lead to a decrease in the need of subsequent additional surgical procedures. We develop a wearable goggle navigation system for dual-mode optical and ultrasound imaging of suspicious lesions. The system consists of a light source module, a monochromatic CCD camera, an ultrasound system, a Google Glass, and a host computer. It is tested in tissue-simulating phantoms and an ex vivo human breast tissue model. Our experiments demonstrate that the surgical navigation system provides useful guidance for localization and core needle biopsy of simulated tumor within the tissue-simulating phantom, as well as a core needle biopsy and subsequent excision of Indocyanine Green (ICG)—fluorescing sentinel lymph nodes. Our experiments support the contention that this wearable goggle navigation system can be potentially very useful and fully integrated by the surgeon for optimizing many aspects of oncologic surgery. Further engineering optimization and additional in vivo clinical validation work is necessary before such a surgical navigation system can be fully realized in the everyday clinical setting.

Abstract C171: Human anti-Nucleolin recombinant immunoagents as new potential tools for melanoma treatment

Immunotherapy and immune-based anti-cancer molecules represent a valid strategy to fight cancer. However, the choice of tumor-specific surface molecules for the selective targeting of cancer cells still represents a critical step in the study design for the development of new therapeutic approaches. Notably, the development of phage-display technology for the selection of fully human single chain antibody fragments (scFvs) and complete antibodies directed toward tumor-associated antigens has represented a significant advancement for immunotherapy.

Nucleolin (NCL) is one of the most abundant non-ribosomal proteins in the nucleolus. NCL is frequently up-regulated in cancer and in cancer-associated endothelial cells compared to normal tissues, where it is also present on the cell surface. Altered NCL expression and localization results in oncogenic effects such as stabilization of oncogenic mRNAs and microRNAs (miRNAs). Particularly, we demonstrated that NCL enhances the maturation of specific miRNAs (including miR-21, miR-221 and miR-222) causally involved in cancer pathogenesis, aggressiveness, metastatic potential and resistance to several anti-neoplastic treatments.

Because of its oncogenic role and specific expression on cancer cell surface, NCL represents an attractive target for anti-neoplastic therapies. To produce a new anti-NCL molecule with significant potential for clinical applications, we took advantage of phage-display technology to isolate a fully human single chain Fragment variable (scFv), named 4LB5, which binds with high affinity to the RNA binding domain (RBD) of NCL. In our previous study we demonstrated that 4LB5 binds NCL on the surface of aggressive breast cancer cells and inhibits their proliferation both in vitro and in vivo, representing the prototype of a new class of immune-based anti-NCL compounds.

Since NCL expression has been previously reported on the cell surface of skin cancer cell lines and up-regulation of NCL-dependent microRNAs was described in human melanomas, the objective of this project was the assessment of 4LB5 as a potential tool for melanoma therapy.

To this aim, the recombinant scFv was expressed as His6-fusion protein in E.Coli and purified by affinity chromatography, as previously described. By using Enzyme-Linked Immunosorbent Assays (ELISA), we demonstrated a significant binding of 4LB5 to the cell surface of different melanoma cell lines of both human and mouse origins. Notably, inhibition of NCL expression by siRNA transfection reduced the binding of 4LB5 to the cell surface of these cell lines, further supporting its specificity against NCL. Then, we assessed the potential effects of 4LB5 treatment on cell proliferation. Colony formation assays demonstrated that 4LB5 significantly affected cell proliferation of both human and mouse melanoma cell lines.

Our results, in agreement with previously reported data, further support the potential activity of 4LB5 as a tool for cancer therapy, paving the way for additional investigations aimed to fully elucidate the molecular mechanisms affected by this scFv and resulting in its anti-neoplastic therapy in human melanomas. Furthermore, this study supports the idea that anti-NCL immunoagents might represent a class of new anti-cancer compounds with a strong clinical relevance for a wide range of human tumors.

Citation Format: Ashley Braddom, Timothy Richmond, Tyler Sheetz, Erika Reese, Anna Tessari, Kathleen Tober, Christin E. Burd, Claudia De Lorenzo, Edward W. Martin, Jr., Vincenzo Coppola, Michael F. Tweedle, Tatiana Oberyszyn, Carlo M. Croce, Dario Palmieri. Human anti-Nucleolin recombinant immunoagents as new potential tools for melanoma treatment. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C171.

Extracting Infrared Spectra of Protein Secondary Structures Using a Library of Protein Spectra and the Ramachandran Plot

Infrared (IR) spectra from 1200 to 1800 cm(-1) of the pure α-helix and β-sheet secondary structures have been extracted using a covariant least-squares procedure which relates a library of 40 infrared (IR) solution protein spectra from the work of Dong, Carpenter, and Caughey and amino acid fractions of the proteins based on assignments by STRIDE (secondary structure identification) of Eisenhaber and Argos. The excitonic splitting of the β-sheet structures is determined for this library of solution proteins. The method is extended to find a set of spectral basis functions that analyze IR spectra of protein samples for α-helix and β-sheet content. A rigorous error analysis including covariance, the correlations between the input library spectra, was used to justify the results and avoid less meaningful results. The utility of the results on α-helix and β-sheet regions is demonstrated by detecting protein changes due to cancer in imaging Fourier transform IR (FTIR) spectra of liver tissue slices. This work ends with a method to extract IR spectra of less prominent torsional angle distributions.

Feasibility of a multimodal (18)F-FDG-directed lymph node surgical excisional biopsy approach for appropriate diagnostic tissue sampling in patients with suspected lymphoma

Background

¹⁸F-FDG PET/CT imaging is widely utilized in the clinical evaluation of patients with suspected or documented lymphoma. The aim was to describe our cumulative experience with a multimodal ¹⁸F-FDG-directed lymph node surgical excisional biopsy approach in patients with suspected lymphoma.

Methods

Thirteen patients (mean age 51 (±16;22–76) years), with suspected new or suspected recurrent lymphoma suggested by ¹⁸F-FDG-avid lesions seen on prior diagnostic whole-body PET/CT imaging, were injected IV with ¹⁸F-FDG prior to undergoing same-day diagnostic lymph node surgical excisional biopsy in the operating room. Various ¹⁸F-FDG detection strategies were used on the day of surgery, including, (1) same-day pre-resection patient PET/CT; (2) intraoperative gamma probe assessment; (3) clinical scanner specimen PET/CT imaging of whole surgically excised tissue specimens; (4) specimen gamma well counts; and/or (5) same-day post-resection patient PET/CT.

Results

Same-day ¹⁸F-FDG injection dose was 14.8 (±2.4;12.5-20.6) millicuries or 548 (±89;463–762) megabecquerels. Sites of ¹⁸F-FDG-avid lesions were 4 inguinal, 3 cervical, 3 abdominal/retroperitoneal, 2 axillary, and 1 gluteal region subcutaneous tissue. Same-day pre-resection patient PET/CT was performed on 6 patients. Intraoperative gamma probe assessment was performed on 13 patients. Clinical scanner PET/CT imaging of whole surgically excised tissue specimens was performed in 10 cases. Specimen gamma well counts were performed in 6 cases. Same-day post-resection patient PET/CT imaging was performed on 8 patients. Time from ¹⁸F-FDG injection to same-day pre-resection patient PET/CT, intraoperative gamma probe assessment, and same-day post-resection patient PET/CT were 76 (±8;64–84), 240 (±63;168–304), and 487 (±104;331–599) minutes, respectively. Time from ¹⁸F-FDG injection to clinical scanner PET/CT of whole surgically excised tissue specimens was 363 (±60;272–446) minutes. Time from ¹⁸F-FDG injection to specimen gamma well counts was 591 (±96;420–689) minutes. Intraoperative gamma probe assessment successfully identified ¹⁸F-FDG-avid lesions in 12/13 patients. Histopathologic evaluation confirmed lymphoma in 12/13 patients and benign disease in 1/13 patients.

Conclusions

A multimodal approach to ¹⁸F-FDG-directed lymph node surgical excisional biopsy for suspected lymphoma is technically feasible for guiding appropriate diagnostic tissue sampling of lymph nodes seen as ¹⁸F-FDG-avid lesions on diagnostic ¹⁸F-FDG PET/CT imaging.

Intraoperative Use of a Portable Large Field of View Gamma Camera and Handheld Gamma Detection Probe for Radioguided Localization and Prediction of Complete Surgical Resection of Gastrinoma: Proof of Concept

BACKGROUND

Surgical management of Zollinger-Ellison syndrome (ZES) relies on localization and resection of all tumor foci. We describe the benefit of combined intraoperative use of a portable large field of view gamma camera (LFOVGC) and a handheld gamma detection probe (HGDP) for indium-111 ((111)In)-pentetreotide radioguided localization and confirmation of gastrinoma resection in ZES.

STUDY DESIGN

Five patients (6 cases) with (111)In-pentetreotide-avid ZES were evaluated. Patients were injected with (111)In-pentetreotide for diagnostic imaging the day before surgery. Intraoperatively, an HGDP and LFOVGC were used to localize (111)In-pentetreotide-avid lesions, guide resection, assess specimens for (111)In-pentetreotide activity, and to verify lack of abnormal post-resection surgical field activity.

RESULTS

Large field of view gamma camera imaging and HGDP-assisted detection were helpful for localization and guided resection of tumor and removal of (111)In-pentetreotide-avid tumor foci in all cases. In 3 of 5 patients (3 of 6 cases), these techniques led to detection and resection of additional tumor foci beyond those detected by standard surgical techniques. The (111)In-pentetreotide-positive or-negative specimens correlated with neuroendocrine tumors or benign pathology, respectively. In one patient with mild residual focal activity on post-resection portable LFOVGC imaging, thought to be artifact, had recurrence of disease in the same area 5 months after surgery.

CONCLUSIONS

Real-time LFOVGC imaging and HGDP use for surgical management of gastrinoma improve success of localizing and resecting all neuroendocrine tumor-positive tumor foci, providing instantaneous navigational feedback. This approach holds potential for improving long-term patient outcomes in patients with ZES.

Ex vivo electrical impedance measurements on excised hepatic tissue from human patients with metastatic colorectal cancer

Point-wise ex vivo electrical impedance spectroscopy measurements were conducted on excised hepatic tissue from human patients with metastatic colorectal cancer using a linear four-electrode impedance probe. This study of 132 measurements from 10 colorectal cancer patients, the largest to date, reports that the equivalent electrical conductivity for tumor tissue is significantly higher than normal tissue (p < 0.01), ranging from 2-5 times greater over the measured frequency range of 100 Hz-1 MHz. Difference in tissue electrical permittivity is also found to be statistically significant across most frequencies. Furthermore, the complex impedance is also reported for both normal and tumor tissue. Consistent with trends for tissue electrical conductivity, normal tissue has a significantly higher impedance than tumor tissue (p < 0.01), as well as a higher net capacitive phase shift (33° for normal liver tissue in contrast to 10° for tumor tissue).

Complex chronic conditions in Rhode Island's pediatric populace: implications for palliative and hospice services, 2000-2012

BACKGROUND

Pediatric patients with complex chronic conditions (CCC) can benefit from pediatric palliative and hospice care (PP/HC) services. PP/HC can be delivered in a variety of health care settings and for a multitude of conditions, but data on hospitalization patterns and on secondary illnesses in pediatric CCC patients remains scant.

OBJECTIVE

The study objective was to describe mortality trends for Rhode Island resident children aged 0-17 years, along with the demographics, subtypes, sites of death, and comorbidities of those with CCC.

METHODS

This was a retrospective cohort study using demographic, hospitalization, and clinical data from all Rhode Island Department of Health death certificates from 2000 to 2012.

RESULTS

Among the 1422 Rhode Island children aged 0-17 years old who died from 2000 to 2012, CCCs accounted for 27% (279/1049) of medically related deaths and 62% (145/233) of such deaths after infancy. CCC deaths were more likely at home (OR 5.202, 95% CI 2.984-9.203, p<0.001) and to have had a secondary cause of death documented (OR 3.032, 95% CI 2.259-4.067, p<0.001) than were other medically related deaths. Infants with CCCs were more likely to die in an inpatient setting (OR 5.141, 95% CI 2.718-10.026, p<0.001), whereas 1-17 year-olds with CCCs were more likely to die at home (OR 5.346, 95% CI 2.200-14.811, p<0.001) or in an emergency department (OR 3.281, 95% CI 1.363-8.721, p<0.040).

CONCLUSIONS

CCCs constitute a significant proportion of medically related pediatric deaths in Rhode Island and are associated with both secondary comorbidities and death at home. Specialized, multidisciplinary services are warranted and PP/HC is crucial for patient and family support.

Comparison of two threshold detection criteria methodologies for determination of probe positivity for intraoperative in situ identification of presumed abnormal 18F-FDG-avid tissue sites during radioguided oncologic surgery

Background

Intraoperative in situ identification of ¹⁸F-FDG-avid tissue sites during radioguided oncologic surgery remains a significant challenge for surgeons. The purpose of our study was to evaluate the 1.5-to-1 ratiometric threshold criteria method versus the three-sigma statistical threshold criteria method for determination of gamma detection probe positivity for intraoperative in situ identification of presumed abnormal ¹⁸F-FDG-avid tissue sites in a manner that was independent of the specific type of gamma detection probe used.

Methods

From among 52 patients undergoing appropriate in situ evaluation of presumed abnormal ¹⁸F-FDG-avid tissue sites during ¹⁸F-FDG-directed surgery using 6 available gamma detection probe systems, a total of 401 intraoperative gamma detection probe measurement sets of in situ counts per second measurements were cumulatively taken.

Results

For the 401 intraoperative gamma detection probe measurement sets, probe positivity was successfully met by the 1.5-to-1 ratiometric threshold criteria method in 150/401 instances (37.4%) and by the three-sigma statistical threshold criteria method in 259/401 instances (64.6%) (P < 0.001). Likewise, the three-sigma statistical threshold criteria method detected true positive results at target-to-background ratios much lower than the 1.5-to-1 target-to-background ratio of the 1.5-to-1 ratiometric threshold criteria method.

Conclusions

The three-sigma statistical threshold criteria method was significantly better than the 1.5-to-1 ratiometric threshold criteria method for determination of gamma detection probe positivity for intraoperative in situ detection of presumed abnormal ¹⁸F-FDG-avid tissue sites during radioguided oncologic surgery. This finding may be extremely important for reshaping the ongoing and future research and development of gamma detection probe systems that are necessary for optimizing the in situ detection of radioisotopes of higher-energy gamma photon emissions used during radioguided oncologic surgery.

18F-FDG PET/CT oncologic imaging at extended injection-to-scan acquisition time intervals derived from a single-institution 18F-FDG-directed surgery experience: feasibility and quantification of 18F-FDG accumulation within 18F-FDG-avid lesions and background tissues

Background

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) is a well-established imaging modality for a wide variety of solid malignancies. Currently, only limited data exists regarding the utility of PET/CT imaging at very extended injection-to-scan acquisition times. The current retrospective data analysis assessed the feasibility and quantification of diagnostic ¹⁸F-FDG PET/CT oncologic imaging at extended injection-to-scan acquisition time intervals.

Methods

¹⁸F-FDG-avid lesions (not surgically manipulated or altered during ¹⁸F-FDG-directed surgery, and visualized both on preoperative and postoperative ¹⁸F-FDG PET/CT imaging) and corresponding background tissues were assessed for ¹⁸F-FDG accumulation on same-day preoperative and postoperative ¹⁸F-FDG PET/CT imaging. Multiple patient variables and ¹⁸F-FDG-avid lesion variables were examined.

Results

For the 32 ¹⁸F-FDG-avid lesions making up the final ¹⁸F-FDG-avid lesion data set (from among 7 patients), the mean injection-to-scan times of the preoperative and postoperative ¹⁸F-FDG PET/CT scans were 73 (±3, 70-78) and 530 (±79, 413-739) minutes, respectively (P < 0.001). The preoperative and postoperative mean ¹⁸F-FDG-avid lesion SUV_max values were 7.7 (±4.0, 3.6-19.5) and 11.3 (±6.0, 4.1-29.2), respectively (P < 0.001). The preoperative and postoperative mean background SUV_max values were 2.3 (±0.6, 1.0-3.2) and 2.1 (±0.6, 1.0-3.3), respectively (P = 0.017). The preoperative and postoperative mean lesion-to-background SUV_max ratios were 3.7 (±2.3, 1.5-9.8) and 5.8 (±3.6, 1.6-16.2), respectively, (P < 0.001).

Conclusions

¹⁸F-FDG PET/CT oncologic imaging can be successfully performed at extended injection-to-scan acquisition time intervals of up to approximately 5 half-lives for ¹⁸F-FDG while maintaining good/adequate diagnostic image quality. The resultant increase in the ¹⁸F-FDG-avid lesion SUV_max values, decreased background SUV_max values, and increased lesion-to-background SUV_max ratios seen from preoperative to postoperative ¹⁸F-FDG PET/CT imaging have great potential for allowing for the integrated, real-time use of ¹⁸F-FDG PET/CT imaging in conjunction with ¹⁸F-FDG-directed interventional radiology biopsy and ablation procedures and ¹⁸F-FDG-directed surgical procedures, as well as have far-reaching impact on potentially re-shaping future thinking regarding the “most optimal” injection-to-scan acquisition time interval for all routine diagnostic ¹⁸F-FDG PET/CT oncologic imaging.

The goals of care conversation: a tool to improve patient care in the nursing home at the end of life

Patients residing in nursing homes may undergo burdensome transitions in care during the final months of life. They may get care they do not want and are unlikely to benefit from. Patients and families may not understand prognosis or the potential benefits of treatment. A "goals of care" conversation can be the critical first step in identifying a patient's wishes and then developing a plan of care that honors those wishes. When the goal of care is to focus on comfort, hospice can be accessed. Hospice can help ensure that the patient's final time is spent in comfort and that the family's needs are attended to both before and after the patient dies.

Origins of electronic band gap reduction in Cr/N codoped TiO2

Recent studies indicated that noncompensated cation-anion codoping of wide-band-gap oxide semiconductors such as anatase TiO2 significantly reduces the optical band gap and thus strongly enhances the absorption of visible light [W. Zhu et al., Phys. Rev. Lett. 103, 226401 (2009)]. We used soft x-ray spectroscopy to fully determine the location and nature of the impurity levels responsible for the extraordinarily large (∼1 eV) band gap reduction of noncompensated codoped rutile TiO2. It is shown that Cr/N codoping strongly enhances the substitutional N content, compared to single element doping. The band gap reduction is due to the formation of Cr 3d3 levels in the lower half of the gap while the conduction band minimum is comprised of localized Cr 3d and delocalized N 2p states. Band gap reduction and carrier delocalization are critical elements for efficient light-to-current conversion in oxide semiconductors. These findings thus raise the prospect of using codoped oxide semiconductors with specifically engineered electronic properties in a variety of photovoltaic and photocatalytic applications.

Site specific discrete PEGylation of (124)I-labeled mCC49 Fab' fragments improves tumor MicroPET/CT imaging in mice

The tumor-associated glycoprotein-72 (TAG-72) antigen is highly overexpressed in various human adenocarcinomas and anti-TAG-72 monoclonal antibodies, and fragments are therefore useful as pharmaceutical targeting vectors. In this study, we investigated the effects of site-specific PEGylation with MW 2-4 kDa discrete, branched PEGylation reagents on mCC49 Fab' (MW 50 kDa) via in vitro TAG72 binding, and in vivo blood clearance kinetics, biodistribution, and mouse tumor microPET/CT imaging. mCC49Fab' (Fab'-NEM) was conjugated at a hinge region cysteine with maleimide-dPEG 12-(dPEG24COOH)3 acid (Mal-dPEG-A), maleimide-dPEG12-(dPEG12COOH)3 acid (Mal-dPEG-B), or maleimide-dPEG12-(m-dPEG24)3 (Mal-dPEG-C), and then radiolabeled with iodine-124 ((124)I) in vitro radioligand binding assays and in vivo studies used TAG-72 expressing LS174T human colon carcinoma cells and xenograft mouse tumors. Conjugation of mCC49Fab' with Mal-dPEG-A (Fab'-A) reduced the binding affinity of the non PEGylated Fab' by 30%; however, in vivo, Fab'-A significantly lengthened the blood retention vs Fab'-NEM (47.5 vs 28.1%/ID at 1 h, 25.1 vs 8.4%/ID at 5 h, p < 0.01), showed excellent tumor to background, better microPET/CT images due to higher tumor accumulation, and increased tumor concentration in excised tissues at 72 h by 130% (5.09 ± 0.83 vs 3.83 ± 1.50%ID/g, p < 0.05). Despite the strong similarity of the three PEGylation reagents, PEGylation with Mal-dPEG-B or -C reduced the in vitro binding affinity of Fab'-NEM by 70%, blood retention, microPET/CT imaging tumor signal intensity, and residual 72 h tumor concentration by 49% (3.83 ± 1.50 vs 1.97 ± 0.29%ID/g, p < 0.05) and 63% (3.83 ± 1.50 vs 1.42 ± 0.35%ID/g, p < 0.05), respectively. We conclude that remarkably subtle changes in the structure of the PEGylation reagent can create significantly altered biologic behavior. Further study is warranted of conjugates of the triple branched, negatively charged Mal-dPEG-A.

Infrared metrics for fixation-free liver tumor detection

Infrared (IR) spectroscopic imaging of human liver tissue slices has been used to identify and characterize liver tumors. Liver tissue, containing a liver metastasis of breast origin (mucinous carcinoma), was surgically removed from a consenting patient and frozen without formalin fixation or dehydration procedures, so that lipids and water remained in the tissues. A set of IR metrics (ratios of various IR peaks) was determined for tumors in fixation-free liver tissues. K-means cluster analysis was used to tell tumor from nontumor. In this case, there was a large reduction in lipid content upon going from nontumor to tumor tissue, and a well-resolved IR spectrum of nontumor liver lipid was obtained and analyzed. These IR metrics may someday guide work on IR spectroscopic diagnostics on patients in the operating room. This work also suggests utility for these methods beyond the identification of liver tumors, perhaps in the study of liver lipids.

Pain, depression, and fatigue: loneliness as a longitudinal risk factor

OBJECTIVE

Pain, depression, and fatigue function as a symptom cluster and thus may share common risk factors. Interpersonal relationships clearly influence health, suggesting that loneliness may promote the development of the pain, depression, and fatigue symptom cluster. We hypothesized that loneliness would be related to concurrent symptom cluster levels and increases in symptom cluster levels over time.

METHOD

We utilized two observational studies with distinct longitudinal samples. Study 1 was a sample of cancer survivors and benign controls (N = 115) assessed annually for 2 years. Study 2 was a sample of older adults caring for a spouse with dementia (caregivers) and non-caregiver controls (N = 229) assessed annually for 4 years. Participants completed annual measures assessing loneliness, pain, depression, and fatigue.

RESULTS

Across both samples, lonelier participants experienced more concurrent pain, depression, and fatigue and larger increases in symptom cluster levels from one year to the next than less lonely participants. Sleep quality did not mediate the results in either study. All analyses were adjusted for relevant demographic and health variables.

CONCLUSIONS

Two longitudinal studies with different populations demonstrated that loneliness was a risk factor for the development of the pain, depression, and fatigue symptom cluster over time. The current research helps identify people most at risk for pain, depression, and fatigue, and lays the groundwork for research about their diagnosis and treatment. These data also highlight the health risks of loneliness; pain, depression, and fatigue often accompany serious illness and place people at risk for poor health and mortality.

Intraoperative detection of ¹⁸F-FDG-avid tissue sites using the increased probe counting efficiency of the K-alpha probe design and variance-based statistical analysis with the three-sigma criteria

BACKGROUND

Intraoperative detection of (18)F-FDG-avid tissue sites during 18F-FDG-directed surgery can be very challenging when utilizing gamma detection probes that rely on a fixed target-to-background (T/B) ratio (ratiometric threshold) for determination of probe positivity. The purpose of our study was to evaluate the counting efficiency and the success rate of in situ intraoperative detection of (18)F-FDG-avid tissue sites (using the three-sigma statistical threshold criteria method and the ratiometric threshold criteria method) for three different gamma detection probe systems.

METHODS

Of 58 patients undergoing (18)F-FDG-directed surgery for known or suspected malignancy using gamma detection probes, we identified nine (18)F-FDG-avid tissue sites (from amongst seven patients) that were seen on same-day preoperative diagnostic PET/CT imaging, and for which each (18)F-FDG-avid tissue site underwent attempted in situ intraoperative detection concurrently using three gamma detection probe systems (K-alpha probe, and two commercially-available PET-probe systems), and then were subsequently surgical excised.

RESULTS

The mean relative probe counting efficiency ratio was 6.9 (± 4.4, range 2.2-15.4) for the K-alpha probe, as compared to 1.5 (± 0.3, range 1.0-2.1) and 1.0 (± 0, range 1.0-1.0), respectively, for two commercially-available PET-probe systems (P < 0.001). Successful in situ intraoperative detection of 18F-FDG-avid tissue sites was more frequently accomplished with each of the three gamma detection probes tested by using the three-sigma statistical threshold criteria method than by using the ratiometric threshold criteria method, specifically with the three-sigma statistical threshold criteria method being significantly better than the ratiometric threshold criteria method for determining probe positivity for the K-alpha probe (P = 0.05).

CONCLUSIONS

Our results suggest that the improved probe counting efficiency of the K-alpha probe design used in conjunction with the three-sigma statistical threshold criteria method can allow for improved detection of 18F-FDG-avid tissue sites when a low in situ T/B ratio is encountered.

Mathematical model of colitis-associated colon cancer

As a result of chronic inflammation of their colon, patients with ulcerative colitis or Crohn's disease are at risk of developing colon cancer. In this paper, we consider the progression of colitis-associated colon cancer. Unlike normal colon mucosa, the inflammed colon mucosa undergoes genetic mutations, affecting, in particular, tumor suppressors TP53 and adenomatous polyposis coli (APC) gene. We develop a mathematical model that involves these genes, under chronic inflammation, as well as NF-κB, β-catenin, MUC1 and MUC2. The model demonstrates that increased level of cells with TP53 mutations results in abnormal growth and proliferation of the epithelium; further increase in the epithelium proliferation results from additional APC mutations. The model may serve as a conceptual framework for further data-based study of the early stage of colon cancer.

Retrospective review of pelvic malignancies undergoing total pelvic exenteration

Background

In patients with locally advanced or recurrent pelvic malignancies, total pelvic exenteration (TPE) may be necessary for curative treatment. Despite improvements in mortality rates since TPE was first described, morbidity rates remain high due to the extensive resection and the aggressiveness of these tumors. We have studied the outcomes of TPE surgery performed at our institution.

Methods

Fifty-three patients with various pelvic pathologies underwent TPE between 2004 and 2010. Patients were divided into two groups based on pathology: colorectal (n = 36) versus non-colorectal (n = 17) malignancies. Demographics, operative reports, pathology reports, periprocedural events, and outcomes were analyzed. Comparison of the two groups was performed using student’s t-test and Fisher’s exact test. Survival curves were constructed using the Kaplan–Meier method and compared using the log rank test.

Results

The colorectal and non-colorectal groups were similar in demographics, operative times, length of stay, estimated blood loss, and rates of preoperative and intraoperative radiation use. Chemotherapy use was increased in the colorectal group compared with the non-colorectal group (55.6% vs. 23.5%, P = 0.04). Complication rates were similar: 86% in the colorectal group and 76% in the non-colorectal group. In the colorectal group, 27.8% of patients developed perineal abscesses, whereas no patients developed these complications in the non-colorectal group (P = 0.02). No survival difference was seen in primary versus recurrent colorectal tumors; however, within the colorectal group there was a survival advantage when comparing R0 resection to R1 and R2 resection combined. Median survival rates were 27.3 months for R0 resection and 10.7 months for R1 and R2 resection combined. The median survival was 21.4 months for the colorectal group and 6.9 months for the non-colorectal group (P = 0.002).

Conclusions

Patients undergoing TPE for colorectal tumors have improved survival when compared with patients undergoing exenteration for pelvic malignancies of other origins. Within the colorectal group, the extent of resection demonstrated a significant survival benefit of an R0 resection compared with R1 and R2 resections. Despite TPE carrying a high morbidity rate, mortality rates have improved and careful patient selection can optimize outcomes.

Cytopathologic evaluation of the in situ margin in patients undergoing hepatectomy

BACKGROUND

Margin status is a predictor of outcome for patients with liver malignancies, although what constitutes a negative margin is controversial. Traditionally, the completeness of resection is estimated by surgical histopathology of the resected specimen margin, despite the in situ margin being potentially more important. The true margin is often altered by parenchymal transection techniques. The authors propose that cytologic assessment of the in situ margin is more specific for determining the true margin.

METHODS

A total of 84 patients with primary or metastatic liver tumors who were undergoing surgical resection were enrolled in this prospective Institutional Review Board-approved study. Specimen and in situ (patient) margins were assessed using a "scrape preparation" cytologic technique and compared with traditional surgical histopathology. Patients were followed for assessment of local disease recurrence.

RESULTS

Follow-up data were complete for 64 patients for a median of 37 months (range, 12 months-56 months). Twenty patients were excluded because of perioperative death (6 patients; 7%) or a follow-up of < 12 months. Seven patients (12.2%) had positive histopathologic specimen margins, but only 1 was found to be positive by cytology (1.8%). No in situ cytologically positive margins were identified along the cut edge of the liver remnant. The rate of intra- or extrahepatic recurrences was 56.7%, whereas the local recurrence rate was 1.8%. One patient with local recurrence demonstrated simultaneous intra- and extrahepatic disease recurrences and had negative margins by all methods of evaluation.

CONCLUSIONS

To the authors' knowledge, the current study is the first to demonstrate that in situ margins can be assessed using cytopathology. This method is quick and can be universally applied. Given the difficulty of accurately assessing margins after hepatectomy, cytopathologic evaluation may be more reflective of the true margin. Cancer (Cancer Cytopathol) 2012. © 2012 American Cancer Society.

Multimodal imaging and detection strategy with 124 I-labeled chimeric monoclonal antibody cG250 for accurate localization and confirmation of extent of disease during laparoscopic and open surgical resection of clear cell renal cell carcinoma

Renal cell carcinoma (RCC) accounts for approximately 85% to 90% of all primary kidney malignancies, with clear cell RCC (ccRCC) constituting approximately 70% to 85% of all RCCs. This study describes an innovative multimodal imaging and detection strategy that uses ¹²⁴I-labeled chimeric monoclonal antibody G250 (¹²⁴I-cG250) for accurate preoperative and intraoperative localization and confirmation of extent of disease for both laparoscopic and open surgical resection of ccRCC. Two cases presented herein highlight how this technology can potentially guide complete surgical resection and confirm complete removal of all diseased tissues. This innovative ¹²⁴I-cG250 (ie, ¹²⁴I-girentuximab) multimodal imaging and detection approach, which would be clinically very useful to urologic surgeons, urologic medical oncologists, nuclear medicine physicians, radiologists, and pathologists who are involved in the care of ccRCC patients, holds great potential for improving the diagnostic accuracy, operative planning and approach, verification of disease resection, and monitoring for evidence of disease recurrence in ccRCC patients.

Repeat hepatectomy for metastatic colorectal cancer is safe but marginally effective

BACKGROUND

Although hepatectomy for metastatic colorectal cancer (mCRC) offers prolonged survival in up to 40% of people, recurrence rates are high, approaching 70%. Many patients experience recurrent disease in the liver after initial hepatectomy. We examined our experience with repeat hepatectomy for mCRC.

METHODS

After Institutional Review Board approval, we reviewed the records of all patients at a single institution who underwent hepatectomy for mCRC. Repeat hepatectomy was defined as partial liver resection any time after the initial hepatectomy for recurrent mCRC. We estimated time to recurrence and survival by using the Kaplan-Meier method and compared outcomes between groups by using the log-rank test.

RESULTS

From 1998 to 2008, 405 patients underwent hepatectomy for mCRC, and 215 (53%) experienced disease recurrence at a median of 13 months. Of 150 patients with liver-only or liver-predominant recurrence, 52 (35%) underwent repeat hepatectomy. The median time to recurrence after repeat hepatectomy was 10 months, and median overall survival was 19 months. There was one (1.9%) perioperative death, and there were 14 (27%) major complications. The median overall survival in the repeat hepatectomy group from the time of recurrence after initial hepatectomy was 22 months, compared with 15 months in the 98 patients with liver recurrence who were not selected for repeat hepatectomy (P=0.02).

CONCLUSIONS

Repeat hepatectomy for mCRC is feasible in highly selected patients, with acceptable perioperative morbidity and mortality. Although repeat hepatectomy should be considered, recurrence rates are high. Although the initial hepatectomy for mCRC is potentially curative, recurrence of metastatic disease in the liver is unlikely to be cured.

A single-institution approach to total pelvic exenteration

The objective of this study was to describe in detail the technique of total pelvic exenteration. Total pelvic exenteration (TPE) was first described in 1948 by Brunschwig. Since its description, complications of the procedure and surgical innovations have changed the approach to this radical surgery. We have described our institutional approach and outcomes of TPE. Fifty-four patients underwent TPE between 2004 and 2010 by the Division of Surgical Oncology at the Ohio State University Medical Center. Fifty-three patients have complete medical records available for review. Outcomes are described and have shaped these techniques. Patients were divided into various groups based on their histology: colorectal (n = 36), gynecologic (n = 6), urologic (n = 5), squamous cell (n = 2), sarcomatous disease (n = 3), and severe infections (n = 1). These were divided into two groups-colorectal (n = 36) and noncolorectal (n = 17)-for analysis. Demographics, operative time, length of stay, and complication rates were similar between the two groups. The median survival was 21.4 months for the colorectal group and 6.9 months for the noncolorectal group. Total pelvic exenteration for colorectal tumors has improved survival when compared with patients undergoing exenteration for pelvic malignancies of other origins. Total pelvic exenteration continues to be associated with high morbidity; however, with appropriate patient selection and proper operative technique, a perioperative mortality of 0 per cent can be achieved.

A Single-Institution Approach to Total Pelvic Exenteration

The objective of this study was to describe in detail the technique of total pelvic exenteration. Total pelvic exenteration (TPE) was first described in 1948 by Brunschwig. Since its description, complications of the procedure and surgical innovations have changed the approach to this radical surgery. We have described our institutional approach and outcomes of TPE. Fifty-four patients underwent TPE between 2004 and 2010 by the Division of Surgical Oncology at the Ohio State University Medical Center. Fifty-three patients have complete medical records available for review. Outcomes are described and have shaped these techniques. Patients were divided into various groups based on their histology: colorectal (n = 36), gynecologic (n = 6), urologic (n = 5), squamous cell (n = 2), sarcomatous disease (n = 3), and severe infections (n = 1). These were divided into two groups—colorectal (n = 36) and noncolorectal (n = 17)—for analysis. Demographics, operative time, length of stay, and complication rates were similar between the two groups. The median survival was 21.4 months for the colorectal group and 6.9 months for the noncolorectal group. Total pelvic exenteration for colorectal tumors has improved survival when compared with patients undergoing exenteration for pelvic malignancies of other origins. Total pelvic exenteration continues to be associated with high morbidity; however, with appropriate patient selection and proper operative technique, a perioperative mortality of 0 per cent can be achieved.

PET/CT imaging of clear cell renal cell carcinoma with I labeled chimeric antibody

Clear cell renal cell carcinoma (ccRCC) presents problems for urologists in diagnosis, treatment selection, intraoperative surgical margin analysis, and long term monitoring. In this paper we describe the development of a radiolabeled antibody specific to ccRCC (124I-cG250) and its potential to help urologists manage each of these problems. We believe 124I-cG250, in conjunction with perioperative Positron emission tomography/computed tomography imaging and intraoperative handheld gamma probe use, has the potential to diagnose ccRCC, aid in determining a proper course of treatment (operative or otherwise), confirm complete resection of malignant tissue in real time, and monitor patients post-operatively.

Single institution experience comparing double-barreled wet colostomy to ileal conduit for urinary and fecal diversion

OBJECTIVE

To compare outcomes and feasibility of double-barreled wet colostomy and ileal conduit (IC) in patients undergoing total pelvic exenteration (TPE).

METHODS

Between 2004 and 2010, 54 patients underwent TPE for pelvic malignancies. Of those patients, 53 had complete records available for analysis. Two groups were identified based on the technique used for urinary diversion, either by way of an IC or a double-barreled wet colostomy (DBWC). Demographics, comorbidities, complications, length of stay, operative times, morbidity, and mortality were compared between the 2 groups.

RESULTS

Forty-three patients (81%) underwent a DBWC and ten patients (19%) underwent an IC. The 2 groups were similar in terms of age, gender, and comorbidities. Eighteen patients underwent an R0 resection (39%) and twenty-eight (61%) patients had a non-R0 resection. Seven patients (13%) had a complete response to therapy with no evidence of malignancy. A majority of the patients (68%) undergoing TPE had colorectal histology. Thirty-day morbidity directly related to complications of urinary or fecal diversion was 78% in the DBWC group and 58% in the IC group. There was no perioperative mortality in either group.

CONCLUSION

DBWC is a safe and feasible alternative to the traditional IC for urinary diversion. This technique is easy to learn and is associated with similar operative times, length of stay, morbidity, and mortality compared with IC.

124I-HuCC49deltaCH2 for TAG-72 antigen-directed positron emission tomography (PET) imaging of LS174T colon adenocarcinoma tumor implants in xenograft mice: preliminary results

Background

¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) is widely used in diagnostic cancer imaging. However, the use of ¹⁸F-FDG in PET-based imaging is limited by its specificity and sensitivity. In contrast, anti-TAG (tumor associated glycoprotein)-72 monoclonal antibodies are highly specific for binding to a variety of adenocarcinomas, including colorectal cancer. The aim of this preliminary study was to evaluate a complimentary determining region (CDR)-grafted humanized C_H2-domain-deleted anti-TAG-72 monoclonal antibody (HuCC49deltaC_H2), radiolabeled with iodine-124 (¹²⁴I), as an antigen-directed and cancer-specific targeting agent for PET-based imaging.

Methods

HuCC49deltaC_H2 was radiolabeled with ¹²⁴I. Subcutaneous tumor implants of LS174T colon adenocarcinoma cells, which express TAG-72 antigen, were grown on athymic Nu/Nu nude mice as the xenograft model. Intravascular (i.v.) and intraperitoneal (i.p.) administration of ¹²⁴I-HuCC49deltaC_H2 was then evaluated in this xenograft mouse model at various time points from approximately 1 hour to 24 hours after injection using microPET imaging. This was compared to i.v. injection of ¹⁸F-FDG in the same xenograft mouse model using microPET imaging at 50 minutes after injection.

Results

At approximately 1 hour after i.v. injection, ¹²⁴I-HuCC49deltaC_H2 was distributed within the systemic circulation, while at approximately 1 hour after i.p. injection, ¹²⁴I-HuCC49deltaC_H2 was distributed within the peritoneal cavity. At time points from 18 hours to 24 hours after i.v. and i.p. injection, ¹²⁴I-HuCC49deltaC_H2 demonstrated a significantly increased level of specific localization to LS174T tumor implants (p = 0.001) when compared to the 1 hour images. In contrast, approximately 50 minutes after i.v. injection, ¹⁸F-FDG failed to demonstrate any increased level of specific localization to a LS174T tumor implant, but showed the propensity toward more nonspecific uptake within the heart, Harderian glands of the bony orbits of the eyes, brown fat of the posterior neck, kidneys, and bladder.

Conclusions

On microPET imaging, ¹²⁴I-HuCC49deltaC_H2 demonstrates an increased level of specific localization to tumor implants of LS174T colon adenocarcinoma cells in the xenograft mouse model on delayed imaging, while ¹⁸F-FDG failed to demonstrate this. The antigen-directed and cancer-specific ¹²⁴I-radiolabled anti-TAG-72 monoclonal antibody conjugate, ¹²⁴I-HuCC49deltaC_H2, holds future potential for use in human clinical trials for preoperative, intraoperative, and postoperative PET-based imaging strategies, including fused-modality PET-based imaging platforms.

Perioperative (18)F-fluorodeoxyglucose-guided imaging using the becquerel as a quantitative measure for optimizing surgical resection in patients with advanced malignancy

BACKGROUND

(18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) scanning is a widely accepted preoperative tumor imaging modality. Herein, we evaluate the becquerel (Bq) as a potential novel quantitative PET measure for application of surgical specimen imaging.

METHODS

Retrospectively, PET-avid lesions that could be followed from preoperative imaging, confidently identified in the operating room, imaged ex vivo, and correlated with histopathology were included in this study. Bq counts from both in vivo (preoperative) and ex vivo (surgical specimen) PET/CT images were measured and correlated with histopathology.

RESULTS

Fifty-five PET-avid lesions in 37 patients were included. Forty-six of 55 PET-avid lesions identified were found to contain malignancy on histopathology. Mean Bq counts for the PET-avid lesions were significantly higher that the adjacent PET-nonavid areas (background) within both in vivo and ex vivo imaging (P < .001 and P < .001, respectively). When analyzing all 55 lesions, we found significant increases in Bq levels. PET-avid lesions from in vivo to ex vivo images (P < .001) without significant increases in Bq levels in PET-nonavid lesions from in vivo to ex vivo images (P = .06). When comparing Bq levels between the 2 groups (malignant and benign), we found significantly higher Bq counts in the malignant group on in vivo imaging (P = .02) as well as significantly lower Bq counts in FDG-nonavid areas on ex vivo imaging (P = .04) within the malignant group. Significant differences in PET-avid to PET-nonavid Becquerels ratios within both in vivo and ex vivo images (P = .004, P = .002 respectively) were found, with ex vivo ratio being significantly higher (P < .001).

CONCLUSIONS

(18)F-FDG PET/CT imaging using Bqs is the potential to discern malignant lesions from benign tissues within both in vivo and ex vivo scans.

Near-infrared fluorescence labeled anti-TAG-72 monoclonal antibodies for tumor imaging in colorectal cancer xenograft mice

Anti-TAG-72 monoclonal antibodies target the tumor-associated glycoprotein (TAG)-72 in various solid tumors. This study evaluated the use of anti-TAG-72 monoclonal antibodies, both murine CC49 and humanized CC49 (HuCC49deltaCH2), for near-infrared fluorescent (NIR) tumor imaging in colorectal cancer xenograft models. The murine CC49 and HuCC49deltaCH2 were conjugated with Cy7 monofunctional N-hydroxysuccinimide ester (Cy7-NHS). Both in vitro and in vivo anti-TAG-72 antibody binding studies were performed. The in vitro study utilized the human colon adenocarcinoma cell line LS174T that was incubated with Cy7, antibody-Cy7 conjugates, or excessive murine CC49 followed by the antibody-Cy7 conjugates and was imaged by fluorescence microscopy. The in vivo study utilized xenograft mice, bearing LS174T subcutaneous tumor implants, that received tail vein injections of Cy7, murine CC49-Cy7, HuCC49deltaCH2-Cy7, or nonspecific IgG-Cy7 and were imaged by the Xenogen IVIS 100 system from 15 min to 288 h. The biodistribution of the fluorescence labeled antibodies was determined by imaging the dissected tissues. The in vitro study revealed that the antibody-Cy7 conjugates bound to LS174T cells and were blocked by excessive murine CC49. The in vivo study demonstrated that murine CC49 achieved a tumor/blood ratio of 15 at 96 h postinjection. In comparison, HuCC49deltaCH2-Cy7 cleared much faster than murine CC49-Cy7 from the xenograft mice, and HuCC49deltaCH2-Cy7 achieved a tumor/blood ratio of 12 at 18 h postinjection. In contrast, Cy7 and Cy7 labeled nonspecific IgG resulted in no demonstrable tumor accumulation. When mice were injected with excessive unlabeled murine CC49 at 6 h before the injection of murine CC49-Cy7 or HuCC49deltaCH2-Cy7, both the intensity and retention time of the fluorescence from the tumor were reduced. In summary, the Cy7 labeled murine CC49 and HuCC49deltaCH2 demonstrate tumor-targeting capabilities in living colorectal cancer xenograft mice and provide an alternative modality for tumor imaging.