Ultrasound-guided Brachytherapy for Cervix Cancer

Radiotherapy and brachytherapy are the definitive treatments for locally advanced cervix cancer. The use of soft-tissue imaging, particularly magnetic resonance imaging, has enhanced their effectiveness and improved clinical outcomes. However, the use of magnetic resonance imaging is largely restricted to well-resourced centres in both the first and developing world and remains elusive to many less advantaged centres, particularly those in areas with a high burden of cervix cancer. Ultrasound is an accessible, affordable and accurate imaging modality that can be used throughout the brachytherapy procedure. Ultrasound is primarily used to ensure safe insertion of the applicator but can also be used to guide planning. The methods used to utilise ultrasound images for planning are described. Ultrasound is particularly useful as a verification aid to confirm applicator placement after patients are moved and transferred around the radiotherapy department. It can also be used to verify the dimensions of treatment volumes over the course of brachytherapy. There is a crucial unmet need for an accessible economical soft-tissue imaging modality in cervical brachytherapy. Ultrasound has the potential to meet this need.

A preliminary evaluation of the circulating leptin/adiponectin ratio in dogs with pituitary-dependent hyperadrenocorticism and concurrent diabetes mellitus

Leptin and adiponectin are thought to modulate insulin sensitivity and pancreatic β-cell function, but there is limited information regarding the adipokine status of hyperglycemic dogs with hyperadrenocorticism. This study aimed to determine whether alterations in the leptin/adiponectin ratio, insulin sensitivity, and/or pancreatic β-cell function are associated with diabetes mellitus (DM) in dogs with pituitary-dependent hyperadrenocorticism (PDH). A total of 48 client-owned dogs were included in this prospective observational study: 20 dogs with PDH (10 normoglycemic and 10 with DM), 15 dogs with DM, and 13 healthy dogs. The serum concentrations of leptin, adiponectin, resistin, interleukin (IL)-1β, IL-6, IL-10, IL-18, and tumor necrosis factor (TNF)-α were measured, and homeostatic model assessment indices (HOMAs) were calculated and compared among the groups. Serum leptin was significantly higher in PDH dogs with and without DM than in healthy and DM dogs, and it was lower in DM dogs than in PDH dogs without DM. Serum adiponectin was significantly lower in PDH dogs with DM than in healthy and PDH dogs, and it was significantly lower in DM dogs than in healthy dogs. Serum IL-10 was significantly higher in PDH dogs with DM than in healthy and PDH dogs without DM. The leptin/adiponectin ratio was significantly higher in PDH dogs with DM than in normoglycemic PDH dogs. Serum IL-6 concentrations were significantly higher in DM dogs than in healthy dogs. Serum IL-1β concentration was significantly higher in DM dogs than in healthy dogs and PDH dogs with DM and without DM. Serum TNF-α and IL-18 concentrations were not different among groups. The HOMA_{β-cell function} was significantly lower in PDH dogs with DM than in normoglycemic PDH dogs, while HOMA_{insulin sensitivity} was significantly lower in PDH dogs with DM than in healthy dogs. These results suggest that adipokine dysregulation, a reduction in insulin sensitivity, and a further impairment in pancreatic β-cell function might predispose PDH dogs to DM. Further longitudinal study will be necessary to confirm this result.

Efficient Prodrug Activator Gene Therapy by Retroviral Replicating Vectors Prolongs Survival in an Immune-Competent Intracerebral Glioma Model

Prodrug activator gene therapy mediated by murine leukemia virus (MLV)-based retroviral replicating vectors (RRV) was previously shown to be highly effective in killing glioma cells both in culture and in vivo. To avoid receptor interference and enable dual vector co-infection with MLV-RRV, we have developed another RRV based on gibbon ape leukemia virus (GALV) that also shows robust replicative spread in a wide variety of tumor cells. We evaluated the potential of GALV-based RRV as a cancer therapeutic agent by incorporating yeast cytosine deaminase (CD) and E. coli nitroreductase (NTR) prodrug activator genes into the vector. The expression of CD and NTR genes from GALV-RRV achieved highly efficient delivery of these prodrug activator genes to RG-2 glioma cells, resulting in enhanced cytotoxicity after administering their respective prodrugs 5-fluorocytosine and CB1954 in vitro. In an immune-competent intracerebral RG-2 glioma model, GALV-mediated CD and NTR gene therapy both significantly suppressed tumor growth with CB1954 administration after a single injection of vector supernatant. However, NTR showed greater potency than CD, with control animals receiving GALV-NTR vector alone (i.e., without CB1954 prodrug) showing extensive tumor growth with a median survival time of 17.5 days, while animals receiving GALV-NTR and CB1954 showed significantly prolonged survival with a median survival time of 30 days. In conclusion, GALV-RRV enabled high-efficiency gene transfer and persistent expression of NTR, resulting in efficient cell killing, suppression of tumor growth, and prolonged survival upon CB1954 administration. This validates the use of therapeutic strategies employing this prodrug activator gene to arm GALV-RRV, and opens the door to the possibility of future combination gene therapy with CD-armed MLV-RRV, as the latter vector is currently being evaluated in clinical trials.

Atlantoaxial bands in small breed dogs: influence of external pressure by the endotracheal tube tie

OBJECTIVES

To determine the prevalence of dorsal cervical spinal compression in a population of dogs susceptible to caudal occipital dysplasia. To determine whether endotracheal tube ties iatrogenically alter the dorsal compression ratio in the atlantoaxial region.

MATERIALS AND METHODS

Prospective, randomised, controlled, cross-over, blinded cohort study of dogs weighing <15 kg and presenting for neurologic signs localised to the cervical region. In mid-sagittal T2-weighted MR images, dorsal cervical compression and cerebellar compression were evaluated. Dorsal cervical compression ratios were calculated and compared to determine the effect of the endotracheal tube tie on the atlantoaxial region depending on whether dogs were in extended or flexed neck position.

RESULTS

Prevalence of dorsal cervical spinal compression consistent with an atlantoaxial band was 32/44 (73%) dogs without tie pressure and 37/44 (84%) dogs with tie pressure. Significantly higher compression ratios were found with tie placement over the craniocervical region. Dorsal compression ratios of dogs with cerebellar compression were significantly greater than those without it.

CLINICAL SIGNIFICANCE

The location of the endotracheal tube tie can influence interpretation of MR images of the craniocervical region of small breed dogs. These breeds more often had greater dorsal cervical spinal compression with tie pressure, especially when they had cerebellar compression.

Abstract ES11-3: Microsurgical treatment of lymphedema

Lymphedema is a chronic, debilitating condition that causes physical and psychological morbidity, affecting up to 250 million people worldwide. In the United States and other developed countries, cancer and its treatments are the most common causes of lymphedema. Lymphedema can evolve into progressive swelling, fibrosis, functional deficits, and chronic infections, thus adversely affecting quality of life and health care costs.

Unfortunately, no definitive treatment for lymphedema currently exists. The advents of microsurgery, and more recently supermicrosurgery, have had a major impact on the evolution of these physiologic procedures, which have gained popularity to help reduce the severity of lymphedema.

Lymphatic Bypass

LVB are typically performed through incisions 2-3 cm in length and the number of bypasses can vary depending on a patient as well as a surgeon. In our prospective study in 100 consecutive patients, we have found that LVB can be effective in reducing lymphedema severity, particularly in patients with early-stage, upper-extremity lymphedema with reasonable amount of intact functioning lymphatic vessels and minimal tissue fibrosis.

One recent technological advance in lymphovenous bypass procedures is the use of indocyanine green (ICG) fluorescence lymphangiography to map lymphatic vessels. ICG fluorescence lymphangiography enables surgeons to locate and make incisions precisely over functional lymphatic vessels for the lymphovenous bypass, substantially reducing operating time and may significantly improve the outcomes of LVB surgeries.

Vascularized Lymph Node Transfer

This procedure aims to bring vascularized tissue and healthy lymph nodes into sites affected by lymphedema. A flap containing lymph nodes can then be harvested typically from either the cervical region, axillary region or from the inguinal region.

One proposed theory for mechanism is that lymphangiogenesis occur via growth factors produced by the transplanted lymph nodes and thereby bridging lymphatic pathways. A second proposed theory of mechanism is that vascularized lymph node transfer act as a lymphatic pump. Recently, simultaneous breast reconstruction using the transverse lower abdominal flap harvested with inguinal lymph nodes have gained popularity as a convenient option for lymphedematous women who desire reconstruction after mastectomy.

Conclusions

Currently there is no cure for lymphedema. Worldwide interest in using microsurgical procedures to treat lymphedema is gaining momentum. However, there is no consensus on the indications for which procedure to perform, when to intervene, or how to comparatively grade outcomes. We need further research and better understanding of lymphatic anatomy and lymphedema pathophysiology. In addition, more prospective and controlled studies are needed to objectively evaluate the outcomes of various treatment methods.

Citation Format: Chang D. Microsurgical treatment of lymphedema [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr ES11-3.

Neuroinvasive West Nile Virus Post-Heart Transplantation: A Case Report

First described in the United States in the late 1990s, West Nile virus (WNV) infection following solid organ transplantation is a rare but life-threatening complication. The many ways in which WNV may be acquired, patient specific risk factors, and variability in clinical severity present challenges to health care providers caring for these patients.

Peritoneal Carcinomatosis from an Unknown Primary Site. Management of 15 Patients

Aims and background

Peritoneal carcinomatosis from an unknown primary site is a rare and ill-defined entity. This work attempts to identify clinical and pathological features of patients with this disease and report the results of an aggressive combined treatment modality.

Methods

Retrospective analysis was performed of medical records of 15 patients with peritoneal carcinomatosis with no primary site identified at a single institution between 1989 and 2000. A primary gastrointestinal cancer was ruled out after a thorough endoscopic and radiologic work-up and complete exploratory surgery.

Results

Four women and 11 men were identified; the average age was 49 years. All patients had cytoreductive surgery with peritonectomies; 4 patients underwent a second-look operation. Perioperative intraperitoneal chemotherapy was given to 10 of the 15 patients, and 9 patients received post-cytoreduction chemotherapy given intraperitoneally (1), systemically (7) or both intraperitoneally and systemically (1). Overall median survival from diagnosis was 19.0 months; 1 patient is alive with disease at 21 months; and 3 patients are disease-free at 17, 38, and 60 months from diagnosis. Significant positive predictive factors for survival were a small volume of ascites (P = 0.02), a large number of peritonectomies performed (P = 0.001), second-look cytoreduction (P = 0.003), perioperative intraperitoneal chemotherapy (P = 0.008) and postoperative chemotherapy (P = 0.01), either intraperitoneal or systemic.

Conclusions

Peritoneal carcinomatosis from an unknown primary site is a rare subset of primary peritoneal malignancy. Aggressive treatment may provide prolonged palliation with occasional long-term survival.

Pharmacokinetics of Intraperitoneal Gemcitabine in a Rat Model

BACKGROUND

Gemcitabine (2'-2' difluorodeoxycytidine) has been shown to possess a broad spectrum of antitumor activity against various malignancies, particularly pancreatic carcinoma. For cancers occurring within the abdominal cavity, the advantage of intraperitoneal (i.p.) chemotherapy over intravenous (i.v.) chemotherapy is the high drug concentration that can be achieved locally. In addition, the cytotoxic effect of several anticancer agents can be enhanced by hyperthermia. Using a rat model, this study was designed to compare i.p. vs i.v. gemcitabine and to evaluate the effect of hyperthermia on i.p. gemcitabine.

METHODS

In the first phase of this study, 18 Sprague Dawley rats were given a single dose of gemcitabine then randomized into three groups according to dose and route of delivery of chemotherapy (12.5 mg/kg--i.v., 12.5 mg/kg--i.p. or 125 mg/kg--i.p.). In a separate experiment (phase 2), 12 Sprague Dawley rats were given a continuous i.p. perfusion of gemcitabine (12.5 mg/kg in 150 mL total perfusate) and randomized into two groups according to the temperature of the peritoneal perfusate (normothermic or hyperthermic). During the course of both experiments, peritoneal fluid and blood were sampled using a standardized protocol. At the end of the procedure the rats were sacrificed and all urine was extracted. Selected tissue samples were taken from rats in the second phase of the study. The concentration of gemcitabine in all samples was determined by high performance liquid chromatography (HPLC).

RESULTS

When gemcitabine was delivered at 12.5 mg/kg (phase 1) the area under the curve (AUC) was significantly higher with i.p. administration as compared to i.v. administration (P = 0.001). The AUC ratio (AUC peritoneal fluid/AUC plasma) was 12.5+/-3.2 for i.p. delivery as opposed to 0.2+/-0.2 for i.v. delivery (P = 0.0002). The AUC ratio for i.p. gemcitabine at 125 mg/kg was 26.8+/-5.8. Although there was no significant difference in drug concentrations between samples from the normothermic and hyperthermic groups, all tissue samples (except stomach) in the hyperthermic group exhibited increased gemcitabine concentrations.

CONCLUSION

These experiments demonstrated that the exposure of peritoneal surfaces to gemcitabine is significantly increased with i.p. gemcitabine. Intraabdominal hyperthermia had no significant effect on the pharmacokinetics of i.p. gemcitabine but there was evidence of increased absorption of gemcitabine in most intraabdominal tissues. Due to the likelihood of a high incidence of microscopic residual disease after resection of a pancreatic carcinoma, clinical studies to evaluate i.p. hyperthermic gemcitabine may be indicated.