Cognitive ergonomics and robotic surgery

Cognitive ergonomics refer to mental resources and is associated with memory, sensory motor response, and perception. Cognitive workload (CWL) involves use of working memory (mental strain and effort) to complete a task. The three types of cognitive loads have been divided into intrinsic (dependent on complexity and expertise), extraneous (the presentation of tasks) and germane (the learning process) components. The effect of robotic surgery on CWL is complex because the postural, visualisation, and manipulation ergonomic benefits for the surgeon may be offset by the disadvantages associated with team separation and reduced situation awareness. Physical fatigue and workflow disruptions have a negative impact on CWL. Intraoperative CWL can be measured subjectively post hoc with the use of self-reported instruments or objectively with real-time physiological response metrics. Cognitive training can play a crucial role in the process of skill acquisition during the three stages of motor learning: from cognitive to integrative and then to autonomous. Mentorship, technical practice and watching videos are the most common traditional cognitive training methods in surgery. Cognitive training can also occur with computer-based cognitive simulation, mental rehearsal, and cognitive task analysis. Assessment of cognitive skills may offer a more effective way to differentiate robotic expertise level than automated performance (tool-based) metrics.

Ergonomic hand positioning overcomes visual perception mismatch in nonsimulated robotic colorectal surgery

The aim of the study was to compare the internal instrument and external surgeon hand positions to determine whether visual perception mismatch (VPM) is a factor during robotic colorectal surgery. Continuous video footage of 24 consecutive robotic colorectal surgery cases were analysed concurrently with sagittal video recordings of surgeon hand positions. Separated sagittal hand positions would indicate nonergonomic positioning without clutching of the robotic controls, either matching the on-screen up/down instrument tip positions (no VPM) or in the opposite direction (true VPM). Variables (30-min surgery time blocks, anatomic target, and task performed), which resulted in hand separation or VPM, were analysed. Operating with the presence of VPM for more than one duration occurred 51 times and nonergonomic sagittal hand positioning occurred 22 times. For an experienced robotic surgeon, ergonomic positioning of the hands is favoured over adjustment for VPM despite the potential higher mental workload.

Workflow disruptions in robot-assisted surgery

Surgical flow disruptions are unexpected deviations from the natural progression which can potentially compromise the safety of the operation. Separation of the surgeon from the patient and team members is the main contributor for flow disruptions (FDs) in robot-assisted surgery (RAS). FDs have been categorised as communication, coordination, surgeon task considerations, training, equipment/ technology, external factors, instrument changes, and environmental factors. There may be an association between FDs and task error rate. Intervention to counter FDs include training, operating room adjustments, checklists, teamwork, communication improvement, ergonomics, technology, guidelines, workflow optimisation, and team briefing. Future studies should focus on identifying the significant disruptive FDs and the impact of interventions on surgical flow during RAS.

Factors affecting upper limb ergonomics in robotic colorectal surgery

The aim of the study was to examine the factors which may influence suboptimal ergonomic surgeon hand positioning during robotic colorectal surgery (RCS). An observational study of 11 consecutive RCS cases from June 2022 to August 2022 was performed. Continuous video footage of RCS cases was analysed concurrently with video recordings of surgeon's hand positions at the console. The outcome studied was the frequency with which either hand remained in a suboptimal ergonomic position outside the predetermined double box outlines, as marked on the surgeon's video, for >1 min. Situations which resulted in poor upper limb ergonomics were dissection in the peripheral operating field location, left-hand use, use of the stapler, dissection of the main mesenteric blood vessels, and multi-quadrant surgery. Being aware of situations when suboptimal ergonomic positions occur can allow surgeons to consciously compensate by using the clutch or pausing to take a rest break.

What does this paper add to the literature?

The study is important because it is the first to look at factors which may influence poor upper limb ergonomics during non-simulated RCS. By recognizing these factors and compensating for them, it may improve surgeon ergonomics with resultant better performance.

Automated performance metrics, learning curve and robotic colorectal surgery

BACKGROUND

The aim of this study was to evaluate the usefulness of Automated Performance Metrics (APMs) in assessing the learning curve.

METHODS

A retrospective review of 85 consecutive patients who underwent total robotic colorectal surgery at a single institution between August 2020 and October 2022 was performed. Patient demographics, operation type, and APMs were collected and analysed. Cumulative summation technique (CUSUM) was used to construct learning curves of surgeon console time (SCT), use of the fourth arm, clutch activation, instrument off screen (number and duration), and cut electrocautery activation.

RESULTS

Two phases with 50 and 35 cases were identified from the CUSUM graph for SCT. The SCT was significantly different between the two phases (176 and 251 min, p < 0.002). After adjustment for SCT, the APMs were not significantly different between the two phases.

CONCLUSIONS

Most APMs do not offer additional learning curve information when compared with SCT analysis alone.

Visualisation ergonomics and robotic surgery

Stereopsis may be an advantage of robotic surgery. Perceived robotic ergonomic advantages in visualisation include better exposure, three-dimensional vision, surgeon camera control, and line of sight screen location. Other ergonomic factors relating to visualisation include stereo-acuity, vergence-accommodation mismatch, visual-perception mismatch, visual-vestibular mismatch, visuospatial ability, visual fatigue, and visual feedback to compensate for lack of haptic feedback. Visual fatigue symptoms may be related to dry eye or accommodative/binocular vision stress. Digital eye strain can be measured by questionnaires and objective tests. Management options include treatment of dry eye, correction of refractive error, and management of accommodation and vergence anomalies. Experienced robotic surgeons can use visual cues like tissue deformation and surgical tool information as surrogates for haptic feedback.

The impact of additional pathology analysis on the diagnosis and management of soft tissue tumours: a 10-year,retrospective study

In order to characterise soft tissue tumours, pathologists often utilise specialised additional tests, or may seek opinions from subspecialist pathologists due to rarity or complex morphology. Additionally, further review may be sought by subspecialist sarcoma pathologists, such as those at our tertiary referral centre in Sydney, Australia. The aim of this study was to examine the impact on diagnosis and management of this external review, following diagnosis at a specialised sarcoma unit. We collated the results of all additional external ancillary tests and specialist reviews over a 10-year period and characterised the impact on the preliminary diagnosis as 'confirmed', 'new' or 'no clear diagnosis'. We subsequently noted whether the additional findings resulted in a clinically significant change in management. Of the 136 cases sent away, 103 patients had their initial diagnosis confirmed, 29 patients received a new diagnosis and, for four patients, the diagnosis remained uncertain. Nine of the 29 patients receiving a new diagnosis had their management altered. This study demonstrated that within our specialised sarcoma unit, the majority of diagnoses provided by our specialist pathologists are confirmed on additional external testing and review, but external review does provide additional assurance and benefit to the patient.

CCNE1 and survival of patients with tubo-ovarian high-grade serous carcinoma: An Ovarian Tumor Tissue Analysis consortium study

BACKGROUND

Cyclin E1 (CCNE1) is a potential predictive marker and therapeutic target in tubo-ovarian high-grade serous carcinoma (HGSC). Smaller studies have revealed unfavorable associations for CCNE1 amplification and CCNE1 overexpression with survival, but to date no large-scale, histotype-specific validation has been performed. The hypothesis was that high-level amplification of CCNE1 and CCNE1 overexpression, as well as a combination of the two, are linked to shorter overall survival in HGSC.

METHODS

Within the Ovarian Tumor Tissue Analysis consortium, amplification status and protein level in 3029 HGSC cases and mRNA expression in 2419 samples were investigated.

RESULTS

High-level amplification (>8 copies by chromogenic in situ hybridization) was found in 8.6% of HGSC and overexpression (>60% with at least 5% demonstrating strong intensity by immunohistochemistry) was found in 22.4%. CCNE1 high-level amplification and overexpression both were linked to shorter overall survival in multivariate survival analysis adjusted for age and stage, with hazard stratification by study (hazard ratio [HR], 1.26; 95% CI, 1.08-1.47, p = .034, and HR, 1.18; 95% CI, 1.05-1.32, p = .015, respectively). This was also true for cases with combined high-level amplification/overexpression (HR, 1.26; 95% CI, 1.09-1.47, p = .033). CCNE1 mRNA expression was not associated with overall survival (HR, 1.00 per 1-SD increase; 95% CI, 0.94-1.06; p = .58). CCNE1 high-level amplification is mutually exclusive with the presence of germline BRCA1/2 pathogenic variants and shows an inverse association to RB1 loss.

CONCLUSION

This study provides large-scale validation that CCNE1 high-level amplification is associated with shorter survival, supporting its utility as a prognostic biomarker in HGSC.

Improving ergonomics for the bedside assistant in robotic colorectal surgery

The aim of the study was to document when significant bedside assistant (BA) and robotic arm collisions occurred during robotic colorectal surgery (RCS). An observational study of 10 consecutive RCS cases, from May 2022 to September 2022, was performed. Situations when there was significant collision between BA arm and robotic arm (to cause inadvertent movement of the assistant instrument) were documented. The assistant port was randomly placed to the right or the left side of the camera port. Situations which led to detrimental BA ergonomics include dissection at the most peripheral working field, proximity of the target (mesenteric vessels), small bowel retraction, placement of the assistant port in the medial position (on the left side of the camera port), during intra-corporeal suturing and robotic stapler use. The robotic console surgeon can predictably identify and avoid situations when injury to the BA may occur.

Gene-Expression Profiling of Mucinous Ovarian Tumors and Comparison with Upper and Lower Gastrointestinal Tumors Identifies Markers Associated with Adverse Outcomes

PURPOSE

Advanced-stage mucinous ovarian carcinoma (MOC) has poor chemotherapy response and prognosis and lacks biomarkers to aid stage I adjuvant treatment. Differentiating primary MOC from gastrointestinal (GI) metastases to the ovary is also challenging due to phenotypic similarities. Clinicopathologic and gene-expression data were analyzed to identify prognostic and diagnostic features.

EXPERIMENTAL DESIGN

Discovery analyses selected 19 genes with prognostic/diagnostic potential. Validation was performed through the Ovarian Tumor Tissue Analysis consortium and GI cancer biobanks comprising 604 patients with MOC (n = 333), mucinous borderline ovarian tumors (MBOT, n = 151), and upper GI (n = 65) and lower GI tumors (n = 55).

RESULTS

Infiltrative pattern of invasion was associated with decreased overall survival (OS) within 2 years from diagnosis, compared with expansile pattern in stage I MOC [hazard ratio (HR), 2.77; 95% confidence interval (CI), 1.04-7.41, P = 0.042]. Increased expression of THBS2 and TAGLN was associated with shorter OS in MOC patients (HR, 1.25; 95% CI, 1.04-1.51, P = 0.016) and (HR, 1.21; 95% CI, 1.01-1.45, P = 0.043), respectively. ERBB2 (HER2) amplification or high mRNA expression was evident in 64 of 243 (26%) of MOCs, but only 8 of 243 (3%) were also infiltrative (4/39, 10%) or stage III/IV (4/31, 13%).

CONCLUSIONS

An infiltrative growth pattern infers poor prognosis within 2 years from diagnosis and may help select stage I patients for adjuvant therapy. High expression of THBS2 and TAGLN in MOC confers an adverse prognosis and is upregulated in the infiltrative subtype, which warrants further investigation. Anti-HER2 therapy should be investigated in a subset of patients. MOC samples clustered with upper GI, yet markers to differentiate these entities remain elusive, suggesting similar underlying biology and shared treatment strategies.

Mesenchymal chondrosarcoma: An Australian multi-centre cohort study

BACKGROUND

Mesenchymal chondrosarcoma (MCS) is an ultra-rare sarcoma that follows a more aggressive course than conventional chondrosarcoma. This study evaluates prognostic factors, treatments (surgery, chemotherapy, and radiation), and outcomes in an Australian setting.

METHODS

We collected demographics, clinicopathological variables, treatment characteristics, and survival status from patients with MCS registered on the national ACCORD sarcoma database. Outcomes include overall survival (OS) and progression-free survival (PFS).

RESULTS

We identified 22 patients with MCS between 2001-2022. Median age was 28 (range 10-59) years, 19 (86%) had localised disease at diagnosis of whom 16 had surgery (84%), 11 received radiation (58%), and 10 chemotherapy (53%). Ten (52%) developed recurrence and/or metastases on follow-up and three patients with initial metastatic disease received surgery, radiation, and chemotherapy. At a median follow-up of 50.9  (range 0.4-210) months nine patients had died. The median OS was 104.1 months (95% CI 25.8-182.3). There was improved OS for patients with localised disease who had surgical resection of the primary (p = 0.003) and those with ECOG 0-1 compared to 2-3 (p = 0.023) on univariate analysis.

CONCLUSIONS

This study demonstrates contemporary Australian treatment patterns of MCS. The role of chemotherapy for localised disease remains uncertain. Understanding treatment patterns and outcomes help support treatment decisions and design of trials for novel therapeutic strategies.

Managing patients with advanced soft tissue sarcoma: Evolving landscape from an Australian perspective

AIM

Despite lack of advances in the first-line systemic therapy, the overall survival (OS) has continued to improve in patients with advanced soft tissue sarcoma (STS) with the recent estimation of median OS at 20 months. Several systemic therapy options are available now for the second-line and beyond, with more treatment tailored to histology and molecular subtype. The aim of this retrospective study was to characterize current patterns of care in managing patients with advanced STS (aSTS) in Australia.

METHODS

Sarcoma databases from 7 Australian sarcoma services were accessed to identify patients diagnosed with locally advanced inoperable and/or metastatic STS between January 1, 2010 and December 31, 2015. Baseline clinicopathological factors and initial treatment patterns were descriptively analyzed. For the Victorian cohort where treatment of aSTS and follow-up details were available, further exploratory analysis was conducted to determine the impact of patient and tumor characteristics and the use of palliative-intent treatment OS.

RESULTS

Of 2261 cases of STS, 671 were deemed as aSTS. Two thirds were relapsed disease with a mean 1.9 years from initial diagnosis. Median age at diagnosis of aSTS was 59 years (18-95 years) and 56.3% was male. Histology classification revealed four main subtypes: undifferentiated pleomorphic sarcoma (UPS) (23.1%), leiomyosarcoma (18.2%), liposarcoma (12.8%), synovial sarcoma (8.2%), and other comprising 14 STS subtypes. For the Victorian cohort (N = 361), approximately 80% of patients accessed palliative-intent treatment of various modalities. Nearly 40% of patients underwent tumor-debulking surgery or metastasectomy, of which lung wedge resection was the most common (N = 83, 47.7%). A total of 438 palliative-intent radiotherapy treatments were delivered to 259 patients (71.7%), with the majority in the form of external beam radiotherapy. Palliative-intent systemic therapy was delivered to 51.5% of patients (N = 186), mostly (73%). Anthracycline-based therapy was the most commonly delivered therapy (N = 135, 72.6%). Approximately half of the patients in each line of therapy failed to proceed to the subsequent line of systemic therapy with 29.4% receiving three or more lines of therapy (N = 55). A total of 18.3% of patient (N = 34) participated in clinical trials or accessed off-label drugs. The median OS for the Victoria cohort was 15.4 months (95% confidence interval: 12.1, 18.2). The UPS histology subtype was associated with poorer OS, whereas receiving any modality of palliative-intent treatment conferred survival benefit.

CONCLUSION

In Australia, aSTS is managed with diverse treatment approaches comprising various therapy modalities. Further work is planned in describing healthcare resource utilization and estimating costs by this patient cohort.

The learning curve to attain surgical competency in robotic colorectal surgery

INTRODUCTION

The aim of the study was to assess the robotic colorectal surgery (RCS) learning curve of an experienced surgeon.

METHODS

A retrospective review of 117 consecutive patients who underwent total RCS at a single institution between October 2018 and July 2021 was performed. Patient demographics, surgery indications, operation type, intraoperative data, histopathology, morbidity and mortality, and length of stay were analysed. Cumulative summation technique (CUSUM) was used to construct a learning curve of surgeon console and total operation times (SCT and TOT).

RESULTS

There was no open conversion, positive resection margin and mortality in the study population. There were four Clavien-DIndo grade III complications and one local recurrence. The range for SCT was 18-855 min (mean 214, median 211) and TOT was 68-937 min (mean 302, median 291). The SCT CUSUM graph identified change in slope at cases 44 and 88, which divided the learning curve into three distinct phases. Patient demographics were similar through the three phases. There was proportionally more cancer cases performed in the first phase (P = 0.001). The mean SCT was significantly higher in Phase 2 when compared with Phases 1 and 3 (P = 0.03). The failure rate was similar through the three phases. There was a non-significant steady decline in LOS over the three phases, from 6.9 to 6.1 days.

CONCLUSION

Experienced colorectal surgeons can perform robotic surgery safely, even on patients with high complexity early in the learning curve. Audit of patient outcome should be an important component of learning curve assessment.

Ergonomic port placement in robotic colorectal surgery

AIM

The aim of the study was to determine how spacing between ports and alignment of ports (oblique or vertical) influences manipulation angles in robotic colorectal surgery.

METHOD

Abdominal CT scans of 10 consecutive robotic right hemicolectomy and 10 consecutive robotic high anterior resection patients were analysed. The manipulation angles were calculated using fixed points on the preoperative abdominal coronal CT scan. Port placements were marked on the CT scan. The fixed points used to measure the manipulation angles were from the most lateral part of the caecum, hepatic flexure, splenic flexure, the descending colon/sigmoid colon junction and the sigmoid colon/rectum junction.

RESULTS

For right hemicolectomy and high anterior resection surgery, a port spacing of 8 cm compared with 6 cm resulted in greater manipulation angles. With 6-cm port spacing, wider manipulation angles were not achieved with vertical port alignment compared with oblique alignment except for dissection at the splenic flexure.

CONCLUSIONS

The greatest manipulation angles were achieved with the oblique 8-cm port spacing, which should be used in most cases.

Robotic colorectal surgery and ergonomics

Improved ergonomics for the operating surgeon may be an advantage of robotic colorectal surgery. Perceived robotic ergonomic advantages in visualisation include better exposure, three-dimensional vision, surgeon camera control, and line of sight screen location. Postural advantages include seated position and freedom from the constraints of the sterile operating field. Manipulation benefits include articulated instruments with seven degrees of freedom movement, elimination of fulcrum effect, tremor filtration, and scaling of movement. Potential ergonomic detriments of robotic surgery include lack of haptic feedback, visual, and mental strain from increased operating time and interruptions to workflow from crowding.

Efficacy of MEK inhibition in a recurrent malignant peripheral nerve sheath tumor

The prognosis of recurrent malignant peripheral nerve sheath tumors (MPNST) is dismal, with surgical resection being the only definitive salvage therapy. Treatment with chemoradiation approaches has not significantly improved patient outcomes. Similarly, trials of therapies targeting MPNST genomic drivers have thus far been unsuccessful. Improved understanding of the molecular pathogenesis of MPNST indicates frequent activation of the mitogen-activated protein kinase (MAPK) cell signaling pathway. MEK inhibitors have shown activity in preclinical studies; however, their clinical efficacy has not been reported to date. We describe here a case of sustained complete response to MEK inhibition in an adolescent patient with a recurrent metastatic MPNST with multiple alterations in the MAPK pathway, guided by a precision oncology approach.

A Cross-Sectional Study of Sub-Basal Corneal Nerve Reduction Following Neurotoxic Chemotherapy

Purpose

Sub-basal corneal nerves have been shown to change during neurotoxic chemotherapy treatment. This cross-sectional study investigated corneal nerve morphology in patients who have completed neurotoxic chemotherapy well after treatment cessation and its association with peripheral nerve function.

Methods

Central corneal nerve fiber length (CNFL) and inferior whorl length (IWL), average nerve fiber length (ANFL), corneal nerve fiber density (CNFD) and corneal nerve branch density (CNBD), and nerve fiber area (CNFA) were examined using in vivo corneal confocal microscopy in patients with cancer who had completed treatment with either paclitaxel or oxaliplatin between 3 and 24 months prior to assessment in comparison with 2 separate groups of healthy controls. Neurological assessments were conducted including clinician- and patient-reported outcomes, and neurological grading scales.

Results

Both paclitaxel- (n = 40) and oxaliplatin-treated (n = 30) groups had reduced IWL and ANFL compared to the respective healthy control groups (n = 15 in each group) (paclitaxel: IWL = P = 0.02, ANFL = P = 0.009; and oxaliplatin: IWL = P = 0.008, ANFL P = 0.02). CNFL and CNFD reduction were observed only in the paclitaxel-treated group compared with healthy controls (P = 0.008 and P = 0.02, respectively), whereas CNFA was reduced in the oxaliplatin-treated group (P = 0.04). IWL reduction correlated with worse fine hand dexterity in chemotherapy-treated patients (r = −0.33, P = 0.007).

Conclusions

There is evidence of corneal nerve loss in patients with cancer who have been treated with paclitaxel and oxaliplatin well after treatment cessation associated with worse upper limb function.

Translational Relevance

Sub-basal corneal nerve reduction is evident even after cessation of neurotoxic treatment. In vivo corneal confocal microscopy may be useful in the monitoring of nerve function in patients receiving chemotherapy.

The synergistic inhibitory effect of combining therapies targeting EGFR and mitochondria in sarcomas

Our group previously demonstrated that sarcoma cell lines were insensitive to epidermal growth factor receptor (EGFR) inhibitor gefitinib monotherapy. PENAO, an anti-tumour metabolic compound created in our laboratory, is currently in clinical trials. Considering the positive regulation of tumour energy production by both the EGFR signalling and tumour metabolism pathways, this study aimed to investigate the effect and mechanisms of combination therapy using gefitinib and PENAO in sarcoma cell lines in vitro and in vivo.

PENAO monotherapy reduced proliferation in 12 sarcoma cell lines. Combining gefitinib and PENAO resulted in synergistic inhibition in both a time- and dose-dependent manner in 3 sarcoma cell lines with less prominent monotherapy effects. Combined treatment significantly enhanced cell death and perturbed mitochondrial function. In vivo combination therapy with PENAO and gefitinib was non-toxic to mice and significantly delayed tumour growth and prolonged survival. At 20 days after treatment, tumours from the combination treated mice were significantly smaller than those from untreated and single drug treated mice. The survival curves also showed significant difference across and between groups.

The combination of PENAO and gefitinib in vitro and in vivo, shows promise as a treatment pathway in this poor outcome tumour.

Abstract 3907: Synergistic effect of targeting both CDK4/6 and mTORin sarcoma cell lines

Background: The phosphatidylinositide-3-kinase/Protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) signaling is central for cancer growth, survival and motility. One of the key restraints on cell growth downstream is retinoblastoma (Rb) tumour suppressor, which is negatively regulated by the cyclin-dependent protein kinases (CDK) 4/6 protein. We hypothesize that blocking both the CDK4/6 and the mTOR allows the double brakes to tumour growth.

Aim: Our aim is to investigate whether combination therapy using mTOR and CDK4/6 inhibitors (palbociclib and ridaforolimus) would have a synergistic growth inhibitory effect in sarcoma.

Methods: The effect and mechanism of palbociclib and ridaforolimus was investigated in a panel of twelve sarcoma cell lines by Crystal-violet colorimetric and Western blot assays. HT1080 fibrosarcoma metastatic mouse model was investigated for in vivo therapeutic study.

Results: Palbociclib showed anti-proliferation in all cell lines (IC50s: 0.1-1.1µM), while ridaforolimus had growth inhibition in 10/12 cell lines (IC50s: 0.4-26nM). The palbociclib-ridaforolimus combination achieved synergistic effect (CIs: 0.1-0.9) in 9/12 cell lines, including applying the drugs in different sequence (together or pre-treatment with one drug for 24-48 hours) and ratio (1:1, 1:2, 1:4, 2:1 or 4:1). The Western blot demonstrated that the 2-drug combination further blocked both CDK/Rb/E2F and AKT/mTOR pathways, via promoting apoptosis. In the experimental lung metastatic HT1080 mouse model, using palbocilib (10 and 30mg/kg, every other day) and ridaforolimus (0.1 and 0.3mg/kg, daily for 5 days per week) for 4 weeks synergistically (CI = 0.7) inhibited the development of lung metastases (mean number of colonies: 132 in low combination dose and 38 for high combination dose) compared to monotherapy [243 (palbociclib) and 255 (ridaforolimus) in low dose, 113 and 97 for high dose) and vehicle control (286). In the orthotopic fibrosarcoma HT1080 mouse model, the palbociclib-ridaforolimus combination therapies achieved significant (p&lt;0.001) and synergistic (CI=0.00375) growth inhibitory effect compared to monotherapies and control groups.

Conclusions: This study demonstrated that palbociclib-ridaforolimus combination is active in a variety of sarcoma subtypes and worthy of further development towards a clinical trial.

Citation Format: Xiaochun Wang, David Goldstein, Philip Crowe, Jia-Lin Yang. Synergistic effect of targeting both CDK4/6 and mTORin sarcoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3907.

Targeting the PI3K/PTEN/AKT/mTOR Pathway in Treatment of Sarcoma Cell Lines

BACKGROUND/AIM

Sarcoma carries a poor prognosis prompting the need for targeted therapies aimed at deregulated signaling pathways. These include the PI3K/Akt/mTOR pathway commonly up-regulated in malignancies attributed to loss of PTEN expression. However, PTEN status and activation state of PI3K/Akt/mTOR pathway have not been comprehensively studied in sarcoma. The aims of this study were to characterise PTEN and Akt expression in a panel of sarcoma cell lines and then to examine mTOR inhibition using ridaforolimus.

MATERIALS AND METHODS

PTEN genomic expression was analyzed using Sanger sequencing. PTEN, total Akt (tAkt) and phosphorylated Akt (pAkt) expression were quantified with western blot analysis. Antiproliferative effects of treatment regimens were designed using Chou & Talalay's isobologram and determined with crystal violet assay.

RESULTS

Four cell lines had wild-type PTEN (exons 2 to 8), with normal protein expression. The GCT cell line had a missense mutation in exon 6 (C>T), associated with loss of PTEN protein expression. Increased pAkt expression was found in all cell lines following epidermal growth factor (EGF) stimulation, indicating that wild-type PTEN expression in four cell lines did not inhibit constitutive activation of PI3K/Akt/mTOR pathway. Nonetheless, all cell lines demonstrated sensitivity to ridaforolimus within a clinically relevant dose-range (half-maximal inhibitory concentration (IC₅₀)=0.7-10 nM).

CONCLUSION

PTEN mutation is rare in sarcoma cell lines and constitutive activation of PI3K/Akt/mTOR is independent of PTEN status.

Patterns of care for patients with advanced soft tissue sarcoma: experience from Australian sarcoma services

Background

There is a paucity of data on the current management of patients with advanced soft tissue sarcoma (STS) in the Australian health care setting. This study utilised the Australian sarcoma database to evaluate the patterns of care delivered to patients with advanced STS at Australian sarcoma services.

Methods

Prospectively collected data from six sarcoma centres in Australia were sourced to identify patients diagnosed with advanced STS between 1 January 2010 and 31 December 2012. Descriptive statistics were analysed for patient demographics, clinicopathological characteristics and treatment patterns. Overall survival was estimated using the Kaplan–Meier product limit method.

Results

Of 253 patients with advanced STS, four major STS subtypes were identified: undifferentiated pleomorphic sarcoma (23 %), leiomyosarcoma (17 %), liposarcoma (14 %), and synovial sarcoma (8 %); with the rest grouped as “other STS” (38 %). Approximately one-third of patients received palliative systemic therapy with the most common first-line therapy being doxorubicin alone (50 %). A small percentage of patients participated in clinical trials (20 %). Palliative radiotherapy was utilised mostly for treatment of symptomatic distant metastases and one-third of patients underwent metastasectomy, most commonly for pulmonary metastases. The median overall survival (OS) in this series was 18 months and no significant difference in OS was observed across different STS histological subtypes.

Conclusions

This is the first detailed study outlining patterns of care for Australian patients with advanced STS managed at sarcoma services. These data highlight a particular area of weakness in the lack of clinical trials for sarcoma patients and also serve as an important reference point for understanding how practice may change over time as treatment options evolve.

Targeted therapy in soft tissue sarcoma-a novel direction in therapeutics

Inherent or acquired resistance to chemotherapy is a significant problem in the treatment of soft tissue sarcomas. Over the past decade, the discovery and characterization of aberrant signaling pathways and the identification of agents that can specifically target them has led to their introduction as novel treatment options in soft-tissue sarcomas (STS). Trials of monotherapy with targeted agents have shown results below expectations often because of activation of alternative signaling pathways. This review examines the potential for tactical combinations of these drugs to overcome this problem.

Abstract 1723: Effect and mechanism of PF299804 alone and in combination with STAT3 inhibitor in human sarcoma cell lines

Background: Curative treatment of sarcomas is achieved by surgical resection, supplemented with neoadjuvant chemotherapy and postoperative radiation. Approximately 50% of patients will eventually die. We previously reported that 78% (36/46) of our cohort of patients with soft tissue sarcoma were positive for total EGFR/HER1. The EGFR/HER1 pathway is an important molecular target; its inhibition is now well established clinically in several epithelial-origin tumors. No pan-HER inhibitors have yet been tested in sarcomas. The principal aim of this project was to investigate the effect and mechanism of PF299804 (an irreversible pan-HER inhibitor) therapy alone and in combination with STAT3 inhibitor in human sarcoma cell lines.

Methods: PF299804 mono-therapy and in combination with STAT3 inhibitor (S3I-201) were investigated in a panel of 12 human sarcoma cell lines. Crystal-violet colorimetric and clonogenic assays were used to measure drug effects. Soft agar colony formation assay was used to evaluate anchorage-independent growth (the ability to evade anoikis). For assessing potential mechanisms, we investigated expression and activity of EGFR signalling by Western blot.

Results: HER family receptors (EGFR/HER1, HER2 and HER3) were positively expressed in the sarcoma cell lines representing liposarcoma (778 and 449b), fibrosarcoma (SW684 and HT1080), synovial sarcoma (SW980), fibrous histocytoma (GCT) and osteosarcoma (143B, HOS, MG63, SJSA, U2-OS and Saos-2). IC50 values of PF299804 were more than 1µM in these cell lines, which was about 1000-fold higher than the sensitive control lung cell line PC9. Mechanism studies by Western blot assay found that 200nM PF299804 (emulating total plasma exposure measured in human clinical trial) dramatically suppressed the activation of both EGFR/HER1 and HER2, as well as their representative downstream signalling factors Erk1/2, p38MAPK and SAPK/JNK in ras/raf/MAPK and AKT in PI3K/AKT pathways, but not of STAT3. Combination therapy using PF299804 and STAT3 inhibitor S3I-201 achieved synergistic anti-proliferation in 3 out of 4 sarcoma cell lines (449B, 778, 143B and HOS), representing different subtype, grade, recurrence and metastasis: 449B and 778 are primary well-differentiated and its recurrent liposarcoma cell lines; HOS and 143B are low-metastatic and high- metastatic (HOS with k-ras oncogene transformation) osteosarcoma cell lines, respectively. This synergistic effect was associated with additional down-regulation of phosphorylated STAT3.

Conclusion: Although the second generation irreversible pan-HER inhibitor PF299804 inactivated HER family and downstream pathways, it encountered resistance at least partially due to the STAT3 activation. Therefore, addition of STAT3 inhibitor in PF299804 therapy may block STAT3 activation and achieve synergistic anti-proliferation in sarcoma cell lines.

Citation Format: Xiaochun Wang, David Goldstein, Philip Crowe, Jia-Lin Yang. Effect and mechanism of PF299804 alone and in combination with STAT3 inhibitor in human sarcoma cell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1723. doi:10.1158/1538-7445.AM2014-1723

Abstract A113: Mechanisms of gefitinib alone and in combination therapy in soft tissue sarcoma cell lines

Background: Use of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors gefitinib and erlotinib is now a part of standard care in biologically appropriate subsets in cancers of lung (1). However, a Phase II trial of single agent gefitinib in synovial sarcoma showed a low response (2). Our preliminary data (3) showed that a panel of seven soft tissue sarcoma (STS) cell lines were resistant to gefitinib with IC50 of more than 10µM, and combination therapy with a STAT3 inhibitor achieved synergistic anti-proliferative effect in 6/7 STS cell lines. The principal aim of this study is to investigate the potential mechanisms behind gefitinib mono-therapy and combination with STAT3 inhibitor S3I-201 in STS cell lines.

Methods: We investigated expression and phosphorylation of EGFR and its signal transducers (AKT, Erk1/2, P38 MAPK, SAPK/JNK, STAT1 and STAT3) by Western blot before and after treatment. We further examined the effect of combination therapy on apoptosis (cleaved caspase 3, 7 and cleaved PARP).

Results: We confirmed synergy in additional experiments with drug reduction index for combined therapy of gefitinib ranged from 2.5 to 6.0 and for S3I-201 from 4.5 to 15.7. Western blot showed that EGF induced EGFR phosphorylation (pEGFR) in all seven STS cell lines, while pEGFR was undetectable or weak in the normal cell culture conditions (without supplemental EGF). Furthermore, the EGF-induced pEGFR was completed blocked by gefitinib monotherpy in all these cell lines. We then examined the interaction between EGFR inhibition (in the presence or absence of EGF) and activity of different EGF-EGFR downstream signalling pathways including PI3K/AKT (AKT), Ras/Erk (Erk1/2, p38 MAPK and SAPK/JNK) and JAK/STAT (STAT3 and STAT1) pathways. pAKT was significantly inhibited in all 7 cell lines, pErk1/2 in 6 out of 7 cell lines, pJNK in 5/7, while pP38 was decreased in 2 out of 7 cell lines. In addition, while gefitinib inhibited both pSTAT1 and pSTAT3, the ratio of pSTAT3/pSTAT1 was increased in most (5/7) of STS cell lines. pSTAT3 was further down-regulated after combination therapy with gefitinib and STAT3 inhibitor S3I-201. Cleaved caspase 3, 7 and PARP were further increased in combination therapy compared to gefitinib monotherapy in synergistic cell lines.

Conclusion: Our research suggests gefitinib alone can inhibit both Ras/Erk and PI3K/AKT pathways, but is incomplete for the JAK/STAT pathway, which may be one mechanism for gefitinib resistance in soft tissue sarcoma cell lines. Combination therapy targeting both EGFR and STAT3 further inhibited active STAT3 and induced apoptosis. Therefore concurrent application of EGFR and STAT3 inhibitors is a worthwhile treatment to pursue in anti-sarcoma therapy.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A113.

Citation Format: Xiaochun Wang, David Goldstein, Philip Crowe, Jia-Lin Yang. Mechanisms of gefitinib alone and in combination therapy in soft tissue sarcoma cell lines. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A113.

Uncovering a key to the process of metastasis in human cancers: a review of critical regulators of anoikis

PURPOSE

Anoikis ('homelessness' in Greek) is a form of apoptosis following the detachment of cells from the appropriate extracellular matrix (Chiarugi and Giannoni in Biochem Pharmacol 76:1352-1364, 2008). Resistance to anoikis is a critical mediator of metastasis in cancer by enabling cancer cells to survive during invasion and transport in the blood and lymph. Numerous regulators and mechanisms of anoikis in human cancer have been proposed to date. Consequently, the identification of key regulators of anoikis that can be targeted to at least partially restore anoikis sensitivity in cancer cells is important in the development of therapies to treat metastatic cancer.

METHODS

A literature search focusing on the regulators of anoikis in human cancer was performed on the Medline, Embase and Scopus databases.

RESULTS

Mcl-1, Cav-1, Bcl-(xL), cFLIP, 14-3-3ζ and Bit1 appear to regulate anoikis in human cancer by participating in the intrinsic apoptotic pathway, extrinsic apoptotic pathway or caspase-independent pathways. Mcl-1, Cav-1, Bcl-(xL), cFLIP and 14-3-3ζ are suppressors of anoikis, and their upregulation confers anoikis resistance to cancer cells. Bit1 is a promoter of anoikis and is downregulated to confer anoikis resistance in metastatic cancer.

CONCLUSION

Anoikis is a complex process involving the crosstalk between different signalling pathways. The dysregulated expression of key regulators of anoikis that participate in these signalling pathways promotes anoikis resistance in human cancer. These regulators of anoikis might therefore be the targets for developing therapies to overcome anoikis resistance in metastatic cancer.

Adjunctive ultrasonography to minimize iodinated contrast administration during carotid artery stenting: a randomized trial

PURPOSE

To report a single-center, prospective randomized controlled trial that compared contrast use during ultrasound-assisted carotid artery stenting (CAS) to CAS procedures without ultrasound.

METHODS

Between August 2010 and November 2011, 22 patients (18 men; mean age 72.8 years, range 62-84) with 25 severe symptomatic (n=3) or asymptomatic (n=22) carotid stenoses undergoing an endovascular intervention were randomly allocated (~1.1) to ultrasonography-assisted (n=13) or stand-alone (n=12) CAS. The primary endpoints were contrast use and number of selective cerebral injections. Secondary endpoints were procedure time, fluoroscopy time, any stroke, renal function assessment, major adverse cardiac events (MACE), and death.

RESULTS

In the study period, 23 of 25 scheduled CAS procedures (12 ultrasound-assisted, 11 control) were completed in 20 patients; 2 procedures were aborted owing to friable plaque and difficult guidewire access, respectively. There were no deaths, stroke, MACE, or precipitation of dialysis-dependent renal failure in either group. Iodinated contrast usage was reduced by 61% (45.4±24.4 vs. 17.8±11.9 mL, p=0.002) and number of selective cerebral contrast injections by 49% (8.3 vs. 4.2, p=0.002). Neither time taken to complete the procedure (32.5 vs. 35.4 minutes, p=0.38) nor fluoroscopy time (14.5 vs. 13.9 minutes, p=0.54) differed significantly between the groups. Creatinine levels remained stable after CAS and did not differ between groups.

CONCLUSION

Ultrasonography-assisted CAS is feasible and safe. Its use can significantly lower the usage of iodinated contrast and the number of selective cerebral circulation injections while not prolonging the length of the procedure or the fluoroscopy time.

Abstract 3763: Treatment of soft tissue sarcoma cells by EGFR and/or STAT3 inhibitors

Background: We previously found Epidermal Growth Factor Receptor (EGFR) inhibitor can block liposarcoma cell EGFR (HER1) survival signalling. However, it did not interfere with HER2 regulated Janus Kinases (JAK), and Signal Transducer and Activator of Transcription (STAT) signal transduction. Our research suggested JAK/STAT may be one mechanism for EGFR inhibitor resistance. Targeting both EGFR and STAT3, which has never been tested in sarcoma may overcome this problem. The principal aim of this preliminary study was to investigate the effect and mechanism of both STAT3 inhibitor alone and in combination with EGFR inhibitor in the treatment of soft tissue sarcoma (STS) cell lines. Methods: STAT3 inhibitor (S3I-201) mono-therapy or in combination with EGFR inhibitor Gefitinib was investigated in 7 STS cell lines (449b, 778, SW872, SW684, SW982, GCT and HT1080). Crystal-violet colorimetric and clonogenic assays were used to measure drug effects. For assessing a potential role of treatment, we investigated expression and activity of STAT and EGFR by Western blot and immunohistochemistry staining before and after treatment. Data were analysed using Chou & Talalay method and CalcuSyn software. Results: All 7 STS cell lines expressed phosphorylated/total STAT3 and EGFR. Anti-proliferative and anti-clonogenic effects of S3I-201 monotherapy on STS were dose- and time-dependent. Sensitive cells to S3I-201 (IC50 Δ50μM) were HT1080, SW684, GCT and SW982 (90% HT1080 were inhibited at day 3 post-administration of 25μM drug), partially sensitive cells were 449B and 778, and non-sensitive cells (IC50 ≤ 200μM) were SW872 (only 29% SW872 were inhibited at day 5 with 200μM S3I-201). Western blot analysis of whole-cell lysates from HT1080 showed phosphorylated STAT3 (pSTAT3) levels were significantly diminished after S3I-201 treatment, whereas pSTAT3 were not down-regulated in resistant cells SW872. IC50 of Gefitinib monotherapy on STS were 20 - 40μM, and 778 had minor effect (33% cells were inhibited after 5 days treatment). Combination therapy with Gefitinib and S3I-201 achieved synergistic antiproliferative effect (mean CIs &lt; 0.90) in 6/7 STS cell lines (CI: 449b (0.3-1), 778 (0.1-0.2), SW872 (0.6-0.7), SW684 (0.2-0.5), GCT (0.3-0.4) and HT1080 (0.5-0.6)), except SW982 (1-1.2). For the most synergistic 778 cells, the drug reduction index for Gefitinib and S3I-201 was 5.9 and 12.7. Although treatment with Gefitinib alone inhibited pSTAT3 expression on serum-starved 778, EGF stimulation reversed the inhibition function. However in combination therapy, STAT3 phosphorylation was not induced by EGF stimulation. Conclusion: Combination therapy targeting both EGFR and STAT3 is a worthwhile treatment to pursue in anti-sarcoma therapy. Further studies will focus on potential mechanisms as well as the anti-sarcoma effect in the animal models. These results will have a clinical implication in treatment of STS in the future.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3763. doi:1538-7445.AM2012-3763

Abstract 4416: Significance of IGF-1R and Its signaling pathways in human sarcoma

A 5-year 50% survival rate reflects the inadequacy of available therapies. We aimed to investigate the relationship of IGF-1R signaling factor expression with clinicopathological parameters of soft tissue sarcoma (STS) and patient outcome, as well as the therapeutic effect of targeting IGF-1R combined with chemotherapy in sarcoma cell lines.

Tissue-microarray and immunohistochemistry were used to detect expression of IGF-1R and its signaling factors, pAkt, pERK, pp38, pJNK and pSTAT3 in 93 samples from 89 STS patients. Combination therapy using IGF-1R inhibitor and each of 5 chemotherapueutic agents was investigated in 11 sarcoma cell lines and analysed by Chou-Talalay method. Mechanism studies were also performed.

A strong link between stage and grade with expression of IGF-1R (p&lt;0.033 and p&lt;0.042), pAkt (p&lt;0.004 and p&lt;0.001) and pERK (p=0.002 and p&lt;0.001) in STS was found. Decreased survival correlated with pAkt expression (Multivariate Cox regression p=0.043). Combination treatment of IGF-1R inhibitor with individual chemotherapeutic agents achieved synergistic anti-proliferative effect for all drugs except gemcitabine in some sarcoma cell lines (5/11 carboplatin, 3/11 ifosfamide, 3/11 docetaxel, and 3/11 doxorubicin), accompanied by apoptosis and cytotoxicity. Furthermore, characterisation of IGF-1R signaling interaction by downstream pathway inhibition revealed the importance of activated PI3K and p38 for chemoresistance in a pair of liposarcoma cell lines (synergistic, 778 and antagonistic, SW872). IGF-1R, pAkt and pERK may be predictors of the aggressiveness of STS. IGF-1R inhibition in combination with chemotherapy is a worthwhile strategy to pursue in anti-sarcoma therapy. These results provide a rationale for further clinical evaluation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4416. doi:10.1158/1538-7445.AM2011-4416

Abstract 1655: Mechanism of the synergistic antiproliferative effect of gefitinib and interferon-alpha in sarcoma cell lines

A static 50% 5-year overall survival rate reflects inadequacy of currently available therapies and urgent need to develop treatment strategies for sarcoma. Single epidermal growth factor receptor (EGFR) inhibitor, gefitinib was reported in a phase II trial in synovial sarcoma with a low response rate and short sustained time. Identification of combinations with both a higher proportion of responders and potentially more sustained benefit is needed. One potential partner is interferon-alpha. We have shown in vitro that cell growth signals such as those from an activated EGFR increases resistance to interferon-alpha, and the combination of EGFR inhibitor and interferon-alpha has synergistic antitumor effect in some colon and bladder cancer cell lines. A recent phase II trial of gefitinib and pegylated interferon alfa 2b in previously-treated renal cell carcinoma has demonstrated significant and prolonged disease control benefit with acceptable toxicity. However the effect of the combination therapy in sarcoma is unreported. This study aimed to investigate the effect and mechanisms of this combination therapy in human sarcoma cell lines.

Combination treatment using gefitinib and interferon-alpha was investigated in a panel of sarcoma cell lines (6 soft tissue sarcomas (STS) and 3 osteosarcomas (OS)) with synergy analysis based on the Chou-Talalay combination index. Mechanism studies examined a pair of synergistic and antagonistic liposarcoma cell lines using multiple techniques.

All 9 cell lines expressed wild-type and/or activated EGFR and interferon-alpha receptors but no EGFR gene mutation was identified. Combination treatment of EGFR inhibition and interferon-alpha achieved synergistic antiproliferative effect (combination index (CI) &lt;1 = synergism) in 6/9 sarcoma cell lines (CI for STS: GCT 0.1-0.3, SW684 0.3-0.7, and 778 0.1-0.7; for OS: MG63 0.3-0.7, U2OS 0.3-0.7, and SJSA 0.1-0.3), accompanied by apoptotic and necrotic cell death. The drug reduction index (DRI) at IC50 measures how much the dose of each drug may be reduced when drugs were combined at the IC50 effect level compared with the dose of drug alone. For the most synergistic GCT cell line, the DRI for gefitinib and interferon-alpha was 4.7 and &gt;100. Characterisation of interferon-alpha and EGFR signaling interaction by both pathway inhibition and western blot detection of downstream factor expression discovered that interferon-alpha enhances gefitinib through affecting the ratio of the signal transducer and activator of transcription (STAT) family members (STAT1 up, STAT3 down) to favour tumor cell death. The activated Akt enhanced by interferon-alpha alone was significantly down regulated by combination therapy.

EGFR inhibition combined with interferon-alpha is a worthwhile treatment to pursue in anti-sarcoma therapy. These results provide a rationale for the clinical evaluation of this treatment strategy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1655.

Improving surgical outcomes for patients with cancer: an Australian perspective

The quality of surgical outcomes for cancer patients is influenced by multiple factors that must be addressed by both a systemic and an individual surgeon approach. In Australia, like many other countries, changes to the health care system via both federal and state government health care quality agencies are likely to positively impact outcomes for surgical patients. Surgical audit is an important component of quality surgical practice and the most successful surgical audit in Australia is the National Breast Cancer Audit, run by the Royal Australasian College of Surgeons. The audit has helped to document the standard of breast cancer surgery in Australia and New Zealand and in the process identified areas for improvement.

Guidelines on the insertion and management of central venous access devices in adults

Central venous access devices are used in many branched of medicine where venous access is required for either long-term or a short-term care. These guidelines review the types of access devices available and make a number of major recommendations. Their respective advantages and disadvantages in various clinical settings are outlined. Patient care prior to, and immediately following insertion is discussed in the context of possible complications and how these are best avoided. There is a section addressing long-term care of in-dwelling devices. Techniques of insertion and removal are reviewed and management of the problems which are most likely to occur following insertion including infection, misplacement and thrombosis are discussed. Care of patients with coagulopathies is addressed and there is a section addressing catheter-related problems.

Meta-analysis of sentinel node imprint cytology in breast cancer

BACKGROUND

Intraoperative diagnosis of breast cancer metastases in axillary sentinel nodes is desirable to avoid a second operation for lymphadenectomy. Imprint or touch-preparation cytology is a popular technique that has high specificity and a wide range of sensitivity.

METHODS

A systematic search of electronic databases was performed. Included articles were assessed for methodological and reporting quality. Random-effects model pooled estimates of sensitivity and specificity were calculated. Single-variable and multivariable meta-regression analyses were performed for predictors of sensitivity.

RESULTS

Thirty-one studies were included; all were of good methodological quality but reporting quality varied. Pooled sensitivity of imprint cytology was 63 (95 per cent confidence interval (c.i.) 57 to 69) per cent and specificity was 99 (95 per cent c.i. 98 to 99) per cent. Pooled sensitivity for macrometastases was 81 per cent and that for micrometastases 22 per cent. Mean or median primary tumour size (P = 0.004), the prevalence of metastases (P = 0.103) and the proportion of micrometastases (P = 0.022) were significant risk factors in single-variable meta-regression analysis. Only the proportion of micrometastases remained significant in multivariable analysis. Frozen sectioning had better sensitivity than imprint cytology in three of four direct comparisons.

CONCLUSION

Imprint cytology is simple and rapid, and has good sensitivity for macrometastases. The significance of poor sensitivity for micrometastases will be determined by trials investigating their natural history.

Metallothionein crypt-restricted immunopositivity indices (MTCRII) correlate with aberrant crypt foci (ACF) in mouse colon

Metallothionein (MT) crypt-restricted immunopositivity indices (MTCRII) are colonic crypt stem cell mutation markers that may be induced early and in abundance after mutagen treatment. Metallothionein is the endogenous reporter gene for MTCRII, but is not typically implicated in the classical pathway of colorectal tumorigenesis. Hence, the oncological relevance of MTCRII is unclear. This study tests the hypothesis that MTCRII induced by N-methyl-N-nitrosourea (MNU) and lambda carrageenan (lambdaCgN) associate with aberrant crypt foci (ACF) in mouse colon. Undegraded lambdaCgN and MNU were tested alone and in combination against MTCRII and ACF in Balb/c mice, at 20 weeks after the start of treatment. MTCRII were unaffected by lambdaCgN alone. Combined lambdaCgN/MNU treatments induced greater MTCRII (P < 0.01) as well as greater number (P < 0.001) and crypt multiplicity (P < 0.01) of ACF than MNU alone. MTCRII were approximately 10-fold more numerous than ACF, although linear correlations were observed between these parameters (r = 0.732; P < 0.01). MTCRII are induced by lambdaCgN/MNU interactions in sufficient numbers to provide statistical power from relatively small sample sizes and correlate with ACF formation. MTCRII could thus provide the basis for a novel medium-term murine bioassay relevant to early-stage colorectal tumorigenesis.

Pattern of equestrian injuries presenting to a Sydney teaching hospital

BACKGROUND

Equestrian activities are associated with a high rate of injury. Attempts to reduce the incidence and severity of injury require accurate characterization of risk factors and pattern of injury. The present study was performed to analyse the injuries seen at an Australian centre where a large number of equestrian injuries present.

METHODS

Data were collected prospectively over a 3 year period on all equestrian injuries presenting to the Prince of Wales -Hospital complex. These data were compared against and combined with retrospectively collected data over the preceding 3 years at the same centre.

RESULTS

Two hundred and twenty-one injured equestrians presented (181 consented) in the prospective period of the study, and 208 presented in the retrospective period. Overall, 81% of riders were wearing a helmet at the time of their injury. Helmet use was associated with a significantly lower admission rate (27% vs 55%; P < 0.0001, from combined data). Recreational equestrians had a higher admission rate than professional equestrians, and had a significantly higher head and spine injury rate than the professional group. Rate of helmet use increased from 72% in the retrospective group to 91% in the more recent prospective group, and total admissions decreased from 43% to 14%.

CONCLUSION

Significant and serious injuries are associated with equestrian activities, with the higher risk group being recreational equestrians, and riders not using a helmet. The pattern of injury favours head and spine in recreational and non-helmeted riders, and extremities for professional and helmeted riders. Helmet use is still not universal among riders, although an increase in its use may be contributing to an overall reduction in admission rate. Facial and spinal injuries still occurred in helmeted patients.

Computer-assisted instruction: guiding learning through a key features approach in a community-based medical course

Computer assisted instruction (CAI) offers a valuable adjunct to the difficulties encountered in teaching medical students in a community-based course in rural Australia. The paper outlines the educational planning processes behind the project and provide an outline of the modular solution to the task. Preliminary results show that this approach is feasible and acceptable to guide students' learning.

Management of the axilla in early breast cancer: is it time to change tack?

The standard surgical treatment of the axilla in patients with early breast cancer is about to undergo a radical change. Although axillary dissection is an excellent procedure for both staging and local control, particularly in the clinically positive axilla, it has considerable morbidity and may understage a significant proportion of patients, because it will usually miss micrometastases that can occur in approximately 10% of 'node negative' patients. An increasing number of patients whose tumours are either non-invasive (ductal carcinoma in situ; DCIS), micro-invasive, tubular cancers or low-grade T1a tumours without lymphovascular invasion may be spared axillary surgery because the risk of axillary disease is 0-3%. Many studies, both prospective trials and large retrospective series, show that axillary radiotherapy alone provides similar local control rates to axillary dissection in patients with clinically negative axillas. Primary treatment of the axilla with radiotherapy alone, however, does not allow appropriate staging. Sentinel lymph node biopsy is being increasingly used in patients with breast cancer to provide this information. When a sentinel node is identified it is equal to or better than axillary dissection for staging the axilla and, if the node is positive, it will help select patients who should then proceed to further axillary surgery or axillary radiotherapy. Although sentinel lymph node biopsy is being rapidly adopted in many centres worldwide, the results of randomized controlled trials are needed before it can be recommended as the standard of care.

Teaching on the run: teaching skills for surgical trainees

BACKGROUND

Increasing recognition of the need for training in teaching skills for clinical teachers has coincided with data that registrars and residents conduct much 'on the job' teaching as part of their routine work. While attention has been devoted to training consultants, support for the teaching role of the junior staff has been relatively neglected. The aim of the present report is to describe the teaching experiences of surgical registrars and the impact of a registrar teaching workshop.

METHOD

A half-day programme combining presentation and discussion of surgical teaching with practical skills sessions was designed for surgical registrars at Prince of Wales Hospital. The programme included observation and feedback of brief teaching simulations at the bedside of volunteer patients to newly commenced clinical students, and small group sessions on clinic and operating theatre teaching. A pre-workshop questionnaire sought information about the registrars' own teaching, and a survey 3 months after the workshop determined if any changes to teaching practice had occurred.

RESULTS

The registrars were generally moderately to very confident with their teaching ability but more than 75% felt that they were more confident after the workshop. Only three of 39 registrars had received any instruction aimed at improving their teaching skills, yet 34/39 had taught either on the ward, in the clinics or in the operating room. Follow-up after 3 months revealed that most registrars were enjoying their teaching tasks more, and half had increased their teaching since the workshop and began discussing teaching with their surgical colleagues.

CONCLUSIONS

The present project demonstrates that relatively brief interventions focused on skill development may enhance the confidence and enjoyment of junior clinical teachers and increase the frequency of 'teaching on the run'.

Decreasing lengths of stay: the cost to the community

BACKGROUND

Patients who are discharged earlier from hospital frequently require support from professional and unpaid carers at home after discharge. Hospitals save money per patient by discharging earlier, but it is not known whether the costs to community services and unpaid caters outweigh the savings to the hospital.

METHODS

We prospectively studied the total costs, patient satisfaction, time off work and pain scores of 224 patients who underwent elective herniorrhaphy or laparoscopic cholecystectomy and who lived locally before and after re-engineering the elective surgical service. The components of the re-engineered surgical service were a peri-operative unit, pre-admission anaesthetic assessment based on self-reported questionnaires, day of surgery admissions, enhanced patient education, clinical pathways, and post-acute care.

RESULTS

The patients treated through the re-engineered surgical service had a significantly shorter length of stay (LOS) (mean LOS: 2.2 vs 3.2 days; P < 0.001) but neither they nor their carers required more time off work. Significant determinants of time off work were smoking, heavy lifting at work and a higher pain score at day 7. Patients treated through the re-engineered surgical service recorded significantly higher satisfaction with their treatment. The cost saving to the hospital outweighed the cost of increased services provided in the community, so that the overall cost of providing treatment was over $200 less per patient through the re-engineered service.

CONCLUSIONS

This study demonstrates that changes in care provision that result in shorter LOS and greater cost effectiveness may better meet patients' needs than existing systems.