Location of Local Recurrences Post-Prostatectomy Detected by 18F-DCPFyL and Implications for Salvage Radiotherapy Target Volumes

PURPOSE/OBJECTIVE(S)

The use of prostate-specific membrane antigen (PSMA) PET scans have improved detection of recurrent prostate cancer for biochemical failure post-prostatectomy. The primary aim of this study is to assess the location of local recurrences for PSMA PET positive disease post-prostatectomy relative to anatomical landmarks and to inform salvage radiotherapy contouring guidelines.

MATERIALS/METHODS

This is a retrospective study of patients who underwent a staging PSMA PET-CT scan with 18F-DCFPyL tracer. Eligible patients included men with biochemical recurrence (PSA >0.2ng/mL) post-prostatectomy for prostate adenocarcinoma. PSMA positive local disease (GTV) was marked on the CT scan of the PSMA PET/CT, using the PSMA PET scan fused as the secondary dataset. Reference structures were contoured to compare the positional relationship to the GTV local recurrence. Centroids of each GTV position were measured to the closest border of the reference structures and distance measured.

RESULTS

Forty-five patients had a local recurrence on PSMA PET, 28/45 with prostate bed recurrence and 17/45 with seminal vesicle bed recurrence. The median age was 72.7 years, median pre-treatment PSA 0.515 ng/ml (0.2-11.1), pT2 in 37.8% and pT3 in 62.2, ISUP G2-3 was 66.7%, ISUP 4-5 29.6%, 67% ECE, 15.4% SV involvement and 40% positive margin. For prostate bed recurrences, 93.6% of GTVs were within 15mm from the inferior border of pubic symphysis (median 3.3mm [-9.8-15.4]), 83.9% within 10mm from the VUA (median 3.3mm [-17.4-15.9]), and 80.6% were greater than 10mm from the most superior slice of the penile bulb (median 16.4mm [1-29.5]). Laterally, 83.9% of recurrences were within 10mm of midline and 41.9% within 5mm (median 3.3mm [-13.56-11.59]) and all were contained within levator, 35.5% within 5mm (median 7.7 [1-22.6]) of the medial muscle border. 29.0% were within 5mm from the anterior edge of the rectal wall (median -7mm [-32.3-0.5]). Seminal vesicle bed recurrences were within 17.5mm of upper border of pubic symphysis for 88.9% of patients (median -4.69mm[-30.8to18.2]), 100% were more than 7.5mm inferiorly from the vas deferens (median-22.1mm[-32.7to-7.7]). Laterally, 100% recurrences were more than 7.5mm medial from obturator internus (median 5.37mm [-23.1to37.8]), and 88.9% were more than 10mm from midline (median 23.1mm [2.0-36.6]).

CONCLUSION

The 18F-DCFPyL PSMA PET local recurrences can provide detailed localization of prostate bed and seminal vesicle recurrences. Our data can inform contouring guidelines for salvage radiotherapy to the prostate bed, particularly when using anatomical landmarks to define cranio-caudal extent of target volumes. For target volume laterally, the medial wall of levator ani would encompass all prostate bed recurrences, and no seminal vesicles recurrences were seen at the medial border of the obturator internus muscle.

Routine elastin staining improves venous invasion detection in colorectal carcinoma

BACKGROUND

Colorectal carcinoma is the second most common cause of cancer-related deaths in North America. Invasion of tumor cells into lymphatic and blood vessels is an imperative step in the metastatic progression of colorectal carcinoma.

OBJECTIVES

This is a before-and-after study conducted by the Department of Pathology and Laboratory Medicine of Mount Sinai Medical Center of Florida to assess the impact on venous invasion (VI) detection by implementing routine elastin staining on all tumor-containing blocks per case, where feasible, in colorectal carcinoma (CRC) resection specimens.

METHODS

Clinicopathological parameters of CRC specimens were collected from January until December 2021 (n = 93) for the pre-implementation cohort and from January until December 2022 (n = 61) for the post-implementation cohort.

RESULTS

VI detection was significantly increased in the post-implementation cohort at a rate of 50.8 % compared to only 18.6 % in the pre-implementation cohort. The majority of VI identified in the pre-implementation cohort was extramural (61.5 %), whereas in the post-implementation cohort it was intramural (41.9 %). On univariate analysis, implementation of routine elastin stain was associated with strikingly increased VI detection rates (OR = 4.5, p-value < 0.001). On multivariate analysis, after adjusting for other clinicopathologic variables, elastin staining retained its independent statistically significant impact on VI detection (OR = 2.6, p-value = 0.034). Of note, there were no significant differences in the pre- and post-implementation cohorts in the frequency of nodal metastases, tumor extent, histologic grade, perineural invasion, T stage or M stage.

CONCLUSION

Based on our results and what has been published recently, we confirm an increase in the VI detection rate after implementing routine elastin staining on all tumor-containing blocks in CRC resection specimens.

Relationship between in feed drugs, antibiotics and organic enrichment in marine sediments at Canadian Atlantic salmon aquaculture sites

The presence of in-feed anti-sea lice drugs and their relationship with organic enrichment is poorly understood in sediment surrounding salmon farms. Using data from an aquaculture monitoring program (2018-2020), we describe this relationship at ten sites in four Canadian provinces. Three anti-sea lice pesticides (lufenuron, teflubenzuron, emamectin benzoate and metabolite desmethyl emamectin benzoate), and one antibiotic (oxytetracycline) were detected. Concentrations were often below limits of quantification. Values are also lower than those reported in other aquaculture salmon-producing countries. Highest concentrations, along with organic enrichment, were observed ~200 m of cages with lower concentrations detected up to 1.5 km away. Most samples had at least two drugs present: 75.2 % (British Columbia), 91.4 % (Newfoundland), and 54.8 % (New Brunswick/Nova Scotia) highlighting the potential for cumulative effects. Emamectin benzoate and oxytetracycline were detected four and three years respectively after last known treatments, demonstrating the need for research on overall persistence of compounds.

Heterotopic mesenteric ossification: a report of two cases

Heterotopic mesenteric ossification (HMO) is abnormal bone formation in tissues which usually do not undergo ossification. There are approximately 75 cases reported worldwide. We present two cases of HMO. The first case is that of a 39-year-old man who presented with abdominal pain and a computerized tomography scan of the abdomen and pelvis revealed an apple core lesion resulting in small bowel obstruction. The second case is that of a 36-year-old woman who presented 2 months after undergoing robotic gastric sleeve resection complaining of weakness and emesis. An esophagogram revealed kinking at the distal esophagus. Surgical resection was performed in both, yielding the diagnosis of HMO. There are various theories as to the pathophysiology of HMO, but no clearly defined mechanism has been established. Management should be conservative whenever possible to prevent further ossification with subsequent surgical intervention.

A tertiary hospital audit of the use of medical imaging in the 24 h preceding death

This study aims to investigate the number, modality and indication for imaging studies performed on acute hospital inpatients in the 24 h prior to death. Data were obtained from retrospective analysis of deceased patients from a university affiliated tertiary hospital over a 2-year period and it was found that around one in five inpatients received medical imaging in the last 24 h of their life (364 of 1855, 19.6%).

Spontaneous infarction within a meningioma with negative DWI: an imaging pattern in patients with acute neurological deterioration

Despite being slow growing and presenting with insidious symptoms, patients with a meningioma can have rapid neurological deterioration as a result of increased intracranial pressure (ICP). The cause of raised ICP is often the development of peritumoral oedema, although the mechanism remains poorly understood. Infarction of meningiomas has been reported. The authors report a series of two cases in which spontaneous meningioma infarction and the development of peritumoral oedema resulted in increased ICP, neurological deterioration and presentation.

Medical emergencies in the imaging department of a university hospital: event and imaging characteristics

We aimed to describe the characteristics of medical emergencies that occurred in the medical imaging department (MID) of a university hospital in Melbourne, Australia. A database of 'Respond Medical Emergency Team (MET)' and 'Respond Blue' calls was retrospectively examined for the period June 2003 to November 2010 in relation to events that occurred in the MID. The hospital medical imaging database was also examined in relation to these events and, where necessary, patients' notes were reviewed. Ethics approval was granted by the hospital ethics review board. There were 124 medical emergency calls in the MID during the study period, 28% Respond Blue and 72% Respond MET. Of these 124 calls, 26% occurred outside of usual work hours and 12% involved cardiac arrest. The most common reasons for the emergency calls were seizures (14%) and altered conscious state (13%). Contrast anaphylaxis precipitated the emergency in 4% of cases. In 83% of cases the emergency calls were for patients attending the MID for diagnostic imaging, the remainder being for a procedure. Of the scheduled imaging techniques, 45% were for computed tomography. The scheduled imaging was abandoned due to the emergency in 12% of cases. When performed, imaging informed patient management in 34% of cases in diagnostic imaging and in all cases in the context of image-guided procedures. Medical emergency calls in the MID often occurred outside usual work hours and were attributed to a range of medical problems. The emergencies occurred in relation to all imaging techniques and imaging informed patient management in many cases.

Use of the non-pneumatic anti-shock garment (NASG) to reduce blood loss and time to recovery from shock for women with obstetric haemorrhage in Egypt

Obstetric haemorrhage is one of the leading causes of maternal mortality. In many low-resource settings, delays in transport to referral facilities and in obtaining lifesaving treatment, contribute to maternal deaths. The non-pneumatic anti-shock garment (NASG) is a low-technology pressure device that decreases blood loss, restores vital signs, and has the potential to improve adverse outcomes by helping women survive delays in receiving adequate emergency obstetric care. With brief training, even individuals without medical backgrounds can apply this first-aid device. In this secondary analysis of hospital data from a pre-post intervention study in Egypt (N=364 women with obstetric haemorrhage and shock), 158 received standard care, while 206 received standard care plus the NASG. The NASG significantly reduced blood loss, time to recovery from shock, and, for those with postpartum haemorrhage due to uterine atony who received oxytocin, the NASG had a significant effect on blood loss independent of oxytocin. These results indicate that the NASG may be a valuable innovation for reducing maternal mortality in low-resource settings. Testing at community and household levels will be necessary in order to determine whether the NASG can help women survive the longest delays.

Immunocontraceptive Effects on Female Rabbits Infected with Recombinant Myxoma Virus Expressing Rabbit ZP2 or ZP3

Recombinant myxoma viruses expressing rabbit zona pellucida 2 (rZP2) or rabbit zona pellucida 3 (rZP3) glycoproteins were constructed and tested in domestic rabbits to assess their potential to induce autoimmune infertility. The recombinant virus expressing rZP2 had no effect on fertility or ovarian histology, despite all animals developing antibodies against the rZP2 antigen. However, recombinant viruses expressing rZP3 induced infertility in 70% of animals at the first breeding. Serum antibodies were relatively short-lived, but antibody was bound to zona pellucida of all rabbits from Day 10 onward. There was no obvious correlation between infertility and rZP3 antibody titer. There was a transient inflammatory response in the ovaries of rZP3-immunized rabbits at Day 15 but no T-cell response to rZP3 could be detected at any time. Dysfunctional follicular formation was present in ovaries from rabbits infected with rZP3-expressing viruses 15-40 days postinfection but this had disappeared at later time points. A recombinant myxoma virus expressing a modified rZP3 antigen with the C-terminal hydrophobic putative anchor sequence deleted was also tested. This virus did not induce either infertility or an antibody response against the zona pellucida. Thus, the context of antigen presentation was crucial for an autoimmune response.

Electrochemical release from gold–thiolate electrodes for controlled insertion of ion channels into bilayer membranes

A proof-of-principle experiment to inject a sub-attomole amount of a channel compound into a bilayer membrane is described. The system is based on reductive cleavage of a self-assembled gold-thiol monolayer. In 'macroscopic' experiments, 11-biphenyloxyundecane thiol formed well-ordered monolayers by open-circuit or controlled potential deposition. The products of reductive release were determined by chromatographic analysis. In DMF, the sole reduction product is the corresponding disulfide. In acetonitrile and water, only the thiol is detected. The current efficiency is low due to competing electrolysis of water, and to the low solubility of the released thiol or disulfide layer. On a 'microscopic' scale, the half ester of dithiodibutyric acid with gramicidin was deposited on a gold microelectrode under open circuit conditions. The thoroughly washed microelectrode, placed in proximity to a bilayer, released gramicidin only following a 100 ms pulse of reducing potential. The transfer efficiency of this method for controlled positioning of ion channels is estimated to be better than 1 part in 10(5).

Ion channels from linear and branched bola-amphiphiles

The synthesis and characterization of the ion channel activity of three new bola-amphiphiles is described. These compounds are conceptually derived from a previously reported bis-cyclophane bola-amphiphile through opening of the cyclophanes to acyclic structures and were found to readily form ion channels in planar bilayer membranes as assessed by bilayer clamp single-channel analysis. All three compounds behaved very similarly: the dominant channels formed by all three are Ohmic with specific conductance of 10 +/- 1 pS (NaCl electrolyte) and 39 +/- 1 pS (CsCl electrolyte). Single-ion permeability ratios, determined from dissymmetric electrolyte experiments, showed the selectivity P(Cs(+)) > P(Na(+)) > P(Cl(-)). Less frequently, lower conductance channels were also observed to act independently of the dominant channels. The lifetimes of the dominant channels range from 70 to 280 ms for the three compounds with some very long-lived openings (20-40 s) observed for two of the three. The lower conductance states have shorter lifetimes. This study demonstrates that bis-macrocyclic compounds are not essential for channel formation by bola-amphiphiles, and opens a new class of channel-forming compounds for structure-activity optimization.

Dispersion and toxicity to non-target aquatic organisms of pesticides used to treat sea lice on salmon in net pen enclosures

Pesticides are used extensively in the finfish aquaculture industry to control sea lice infestations on farmed salmon. The most prevalent method of use is to enclose a net pen with an impervious tarpaulin and mix a pesticide solution within that enclosure. After treatment for short periods (1 h) the pesticide solution is released to the environment. Concerns have been raised that there is a potential risk to non-target aquatic organisms from those releases. The fate of dispersing pesticide solutions was measured after six simulated treatments in the Lower Bay of Fundy, New Brunswick. Three simulated treatments were done with azamethiphos and three with cypermethrin. Rhodamine dye was added to all pesticide solutions in order to facilitate tracking of the dispersing plume through real-time measurements of dye concentrations by a flow-through fluorometer coupled with a differential global positioning system (DGPS). Water samples were obtained from within the plumes at various times after release and analysed for pesticide content and toxicity to a benthic amphipod Eohaustorius estuaris. Dye concentrations were detectable for time periods after release which varied from 2 to 5.5 h. Distances travelled by the dye patches ranged from 900 to 3000 m and the dye concentrations at the final sampling period were generally 1/200-1/3000 the pre-release concentrations and cypermethrin concentrations were generally 1/1000-1/2000 the pre-release concentrations. Cypermethrin concentrations in water samples were closely correlated with dye concentrations, indicating that dye analyses were an accurate surrogate for cypermethrin concentrations. Most samples taken after the releases of azamethiphos were not toxic to test organisms in 48 h exposures and none were beyond 20 min post-release. By contrast, almost all samples taken after the release of cypermethrin, even up to 5-h post-release, were toxic. Data indicate the potential to cause toxic effects over areas of hectares from a single release of cypermethrin.

The Vpu protein of human immunodeficiency virus type 1 forms cation-selective ion channels

Vpu is a small phosphorylated integral membrane protein encoded by the human immunodeficiency virus type 1 genome and found in the endoplasmic reticulum and Golgi membranes of infected cells. It has been linked to roles in virus particle budding and degradation of CD4 in the endoplasmic reticulum. However, the molecular mechanisms employed by Vpu in performance of these functions are unknown. Structural similarities between Vpu and the M2 protein of influenza A virus have raised the question of whether the two proteins are functionally analogous: M2 has been demonstrated to form cation-selective ion channels in phospholipid membranes. In this paper we provide evidence that Vpu, purified after expression in Escherichia coli, also forms ion channels in planar lipid bilayers. The channels are approximately five- to sixfold more permeable to sodium and potassium cations than to chloride or phosphate anions. A bacterial cross-feeding assay was used to demonstrate that Vpu can also form sodium-permeable channels in vivo in the E. coli plasma membrane.