Validity of evaluating spinal kinetics without participant-specific kinematics.

Musculoskeletal models are commonly used to estimate in vivo spinal loads under various loading conditions. Typically, participant-specific measured kinematics (PSMK) are coupled with participant-specific models, but obtaining PSMK data can be costly and infeasible in large studies or clinical practice. Thus, we evaluated two alternative methods to estimate spinal loads without PSMK: 1) ensemble average kinematics (EAK) based on kinematics from all participants; and 2) using separately measured individual kinematics (SMIK) from multiple other participants as inputs, then averaging the resulting loads. This study compares the dynamic spine loading patterns and peak loads in older adults performing five lifting tasks using PSMK, EAK and SMIK. Median root mean square errors of EAK and SMIK methods versus PSMK ranged from 18 to 72% body weight for compressive loads and from 2 to 25% body weight for shear loads, with median cross-correlations ranging from 0.931 to 0.991. The root mean square errors and cross-correlations between repeated PSMK trials fell within similar ranges. Compressive peak loads evaluated by EAK and SMIK were not different than PSMK in 12 of 15 cases, while by comparison repeated PSMK trials were not different in 13 of 15 cases. Overall, the resulting spine loading magnitudes and profiles using EAK or SMIK were not notably different than using a PSMK approach, and differences were not greater than between two PSMK trials. Thus, these findings indicate that these approaches may be used to make reasonable estimates of dynamic spinal loading without direct measurement of participant kinematics.

EMG Validation of a Subject-Specific Thoracolumbar Spine Musculoskeletal Model During Dynamic Activities in Older Adults.

Musculoskeletal models can uniquely estimate in vivo demands and injury risk. In this study, we aimed to compare muscle activations from subject-specific thoracolumbar spine OpenSim models with recorded muscle activity from electromyography (EMG) during five dynamic tasks. Specifically, 11 older adults (mean = 65 years, SD = 9) lifted a crate weighted to 10% of their body mass in axial rotation, 2-handed sagittal lift, 1-handed sagittal lift, and lateral bending, and simulated a window opening task. EMG measurements of back and abdominal muscles were directly compared to equivalent model-predicted activity for temporal similarity via maximum absolute normalized cross-correlation (MANCC) coefficients and for magnitude differences via root-mean-square errors (RMSE), across all combinations of participants, dynamic tasks, and muscle groups. We found that across most of the tasks the model reasonably predicted temporal behavior of back extensor muscles (median MANCC = 0.92 ± 0.07) but moderate temporal similarity was observed for abdominal muscles (median MANCC = 0.60 ± 0.20). Activation magnitude was comparable to previous modeling studies, and median RMSE was 0.18 ± 0.08 for back extensor muscles. Overall, these results indicate that our thoracolumbar spine model can be used to estimate subject-specific in vivo muscular activations for these dynamic lifting tasks.

Using static postures to estimate spinal loading during dynamic lifts with participant-specific thoracolumbar musculoskeletal models.

Static biomechanical simulations are sometimes used to estimate in vivo kinetic demands because they can be solved efficiently, but this ignores any potential inertial effects. To date, comparisons between static and dynamic analyses of spinal demands have been limited to lumbar joint differences in young males performing sagittal lifts. Here we compare static and dynamic vertebral compressive and shear force estimates during axial, lateral, and sagittal lifting tasks across all thoracic and lumbar vertebrae in older men and women. Participant-specific thoracolumbar full-body musculoskeletal models estimated vertebral forces from recorded kinematics both with and without consideration of dynamic effects, at an identified frame of peak vertebral loading. Static analyses under-predicted dynamic compressive and resultant shear forces, by an average of about 16% for all three lifts across the thoracic and lumbar spine but were highly correlated with dynamic forces (average r2 > .95). The study outcomes have the potential to enable standard clinical and occupational estimates using static analyses.

Effect of Surgical Humidification on Inflammation and Peritoneal Trauma in Colorectal Cancer Surgery: A Randomized Controlled Trial.

BACKGROUND: Pre-clinical studies indicate that dry-cold-carbon-dioxide (DC-CO2) insufflation leads to more peritoneal damage, inflammation and hypothermia compared with humidified-warm-CO2 (HW-CO2). Peritoneum and core temperature in patients undergoing colorectal cancer (CRC) surgery were compared. METHODS: Sixty-six patients were randomized into laparoscopic groups; those insufflated with DC-CO2 or HW-CO2. A separate group of nineteen patients undergoing laparotomy were randomised to conventional surgery or with the insertion of a device delivering HW-CO2. Temperatures were monitored and peritoneal biopsies and bloods were taken at the start of surgery, at 1 and 3 h. Further bloods were taken depending upon hospital length-of-stay (LOS). Peritoneal samples were subjected to scanning electron microscopy to evaluate mesothelial damage. RESULTS: Laparoscopic cases experienced a temperature drop despite Bair-HuggerTM use. HW-CO2 restored normothermia (≥ 36.5 °C) by 3 h, DC-CO2 did not. LOS was shorter for colon compared with rectal cancer cases and if insufflated with HW-CO2 compared with DC-CO2; 5.0 vs 7.2 days, colon and 11.6 vs 15.4 days rectum, respectively. Unexpectedly, one third of patients had pre-existing damage. Damage increased at 1 and 3 h to a greater extent in the DC-CO2 compared with the HW-CO2 laparoscopic cohort. C-reactive protein levels were higher in open than laparoscopic cases and lower in both matched HW-CO2 groups. CONCLUSIONS: This prospective RCT is in accord with animal studies while highlighting pre-existing damage in some patients. Peritoneal mesothelium protection, reduced inflammation and restoration of core-body temperature data suggest benefit with the use of HW-CO2 in patients undergoing CRC surgery.

Laparoscopic versus open resection for rectal cancer: An individual patient data meta analysis of randomized controlled trials.

BACKGROUND AND AIMS: The role of laparoscopic rectal cancer resection remains controversial. Thus, we aimed to conduct a one-stage meta-analysis with reconstructed patient-level data using randomized trial data to compare long-term oncologic efficacy of laparoscopic and open surgical resection for rectal cancer. METHODS: Medline, EMBASE and Scopus were searched for articles comparing laparoscopic with open surgery for rectal cancer. Primary outcome was disease free survival (DFS) while secondary outcome was overall survival (OS). One-stage meta-analysis was conducted using patient-level survival data reconstructed from Kaplan-Meier curves with Web Plot Digitizer. Shared-frailty and stratified Cox models were fitted to compare survival endpoints. RESULTS: Seven randomized trials involving 1767 laparoscopic and 1293 open resections for rectal cancer were included. There were no significant differences between both groups for DFS and OS with respective hazard ratio estimates of 0.91 (95% CI: 0.78-1.06, p = 0.241) and 0.86 (95% CI:0.73-1.02, p = 0.090). Sensitivity analysis for non-metastatic patients and patients with mid and lower rectal cancer showed no significant differences in OS and DFS between both surgical approaches. In the laparoscopic arm, improved DFS was noted for stage II (HR: 0.73, 95% CI:0.54-0.98, p = 0.036) and stage III rectal cancers (HR: 0.74, 95% CI:0.55-0.99, p = 0.041). CONCLUSIONS: This meta-analysis concludes that laparoscopic rectal cancer resection does not compromise long-term oncologic outcomes compared with open surgery with potential survival benefits for a minimal access approach in patients with stage II and III rectal cancer.

Walking Biomechanics and Spine Loading in Patients With Symptomatic Lumbar Spinal Stenosis.

Symptomatic lumbar spinal stenosis is a leading cause of pain and mobility limitation in older adults. It is clinically believed that patients with lumbar spinal stenosis adopt a flexed trunk posture or bend forward and alter their gait pattern to improve tolerance for walking. However, a biomechanical assessment of spine posture and motion during walking is broadly lacking in these patients. The purpose of this study was to evaluate lumbar spine and pelvic sagittal angles and lumbar spine compressive loads in standing and walking and to determine the effect of pain and neurogenic claudication symptoms in patients with symptomatic lumbar spinal stenosis. Seven participants with symptomatic lumbar spinal stenosis, aged 44-82, underwent a 3D opto-electronic motion analysis during standing and walking trials in asymptomatic and symptomatic states. Passive reflective marker clusters (four markers each) were attached to participants at T1, L1, and S2 levels of the spine, with additional reflective markers at other spinal levels, as well as the head, pelvis, and extremities. Whole-body motion data was collected during standing and walking trials in asymptomatic and symptomatic states. The results showed that the spine was slightly flexed during walking, but this was not affected by symptoms. Pelvic tilt was not different when symptoms were present, but suggests a possible effect of more forward tilt in both standing (p = 0.052) and walking (p = 0.075). Lumbar spine loading during symptomatic walking was increased by an average of 7% over asymptomatic walking (p = 0.001). Our results did not show increased spine flexion (adopting a trunk-flexed posture) and only indicate a trend for a small forward shift of the pelvis during both symptomatic walking and standing. This suggests that provocation of symptoms in these patients does not markedly affect their normal gait kinematics. The finding of increased spine loading with provocation of symptoms supports our hypothesis that spine loading plays a role in limiting walking function in patients with lumbar spinal stenosis, but additional work is needed to understand the biomechanical cause of this increase.

The Influence of Kinematic Constraints on Model Performance During Inverse Kinematics Analysis of the Thoracolumbar Spine.

Motion analysis is increasingly applied to spine musculoskeletal models using kinematic constraints to estimate individual intervertebral joint movements, which cannot be directly measured from the skin surface markers. Traditionally, kinematic constraints have allowed a single spinal degree of freedom (DOF) in each direction, and there has been little examination of how different kinematic constraints affect evaluations of spine motion. Thus, the objective of this study was to evaluate the performance of different kinematic constraints for inverse kinematics analysis. We collected motion analysis marker data in seven healthy participants (4F, 3M, aged 27-67) during flexion-extension, lateral bending, and axial rotation tasks. Inverse kinematics analyses were performed on subject-specific models with 17 thoracolumbar joints allowing 51 rotational DOF (51DOF) and corresponding models including seven sets of kinematic constraints that limited spine motion from 3 to 9DOF. Outcomes included: (1) root mean square (RMS) error of spine markers (measured vs. model); (2) lag-one autocorrelation coefficients to assess smoothness of angular motions; (3) maximum range of motion (ROM) of intervertebral joints in three directions of motion (FE, LB, AR) to assess whether they are physiologically reasonable; and (4) segmental spine angles in static ROM trials. We found that RMS error of spine markers was higher with constraints than without (p < 0.0001) but did not notably improve kinematic constraints above 6DOF. Compared to segmental angles calculated directly from spine markers, models with kinematic constraints had moderate to good intraclass correlation coefficients (ICCs) for flexion-extension and lateral bending, though weak to moderate ICCs for axial rotation. Adding more DOF to kinematic constraints did not improve performance in matching segmental angles. Kinematic constraints with 4-6DOF produced similar levels of smoothness across all tasks and generally improved smoothness compared to 9DOF or unconstrained (51DOF) models. Our results also revealed that the maximum joint ROMs predicted using 4-6DOF constraints were largely within physiologically acceptable ranges throughout the spine and in all directions of motions. We conclude that a kinematic constraint with 5DOF can produce smooth spine motions with physiologically reasonable joint ROMs and relatively low marker error.

Management of primary and metastatic malignant small bowel obstruction, operate or palliate. A systematic review.

BACKGROUND: The management of patients presenting with malignant small bowel obstruction is a challenging paradigm. The aim of this systematic review was to examine different management strategies in these complex patients. The primary outcomes evaluated were the type of intervention, 30-day morbidity and mortality and overall survival rates. METHODS: A systematic literature review of EMBase, Medline, PubMed and the Cochrane Library was performed using Preferred Reporting Items for Systematic reviews and Meta-Analyses for studies reporting on conservative and operative management of malignant small bowel obstruction. RESULTS: Fifteen studies (n = 882 patients) reporting on outcomes for malignant small bowel obstruction were analysed. Outcomes measured were primarily survival and relief of obstructive symptoms. The median age ranged from 52 to 66 years. The most common cause of malignant small bowel obstruction was gynaecological in nature (56%), followed by colorectal (19%). Four hundred and eighty-six patients underwent primary surgical management and the remaining 396 patients were assigned to non-surgical intervention. Median overall survival in the operative studies ranged from 2.5 to 7.4 months compared with 0.9 to 1.9 months (P < 0.05). The 30-day mortality ranged from 13% to 28% in those who underwent surgical interventions versus 2% to 61% in the non-surgical group (P = 0.09). No significant difference in median survival in gastrointestinal (GI) and gynaecological malignancies was observed (4.3 versus 5.0 months, P = 0.12). Morbidity ranged from 21% to 85% in the surgical group and 12% to 29% in the percutaneous groups (P < 0.05). CONCLUSION: Surgical intervention in malignant small bowel obstruction is associated with significant morbidity, although it may improve survival in selected patients with gynaecological and colorectal malignancy. It is imperative that realistic goals and expectations are discussed with patients preoperatively.

Germline whole exome sequencing of a family with appendiceal mucinous tumours presenting with pseudomyxoma peritonei.

BACKGROUND: Familial cases of appendiceal mucinous tumours (AMTs) are extremely rare and the underlying genetic aetiology uncertain. We identified potential predisposing germline genetic variants in a father and daughter with AMTs presenting with pseudomyxoma peritonei (PMP) and correlated these with regions of loss of heterozygosity (LOH) in the tumours. METHODS: Through germline whole exome sequencing, we identified novel heterozygous loss-of-function (LoF) (i.e. nonsense, frameshift and essential splice site mutations) and missense variants shared between father and daughter, and validated all LoF variants, and missense variants with a Combined Annotation Dependent Depletion (CADD) scaled score of ≥10. Genome-wide copy number analysis was performed on tumour tissue from both individuals to identify regions of LOH. RESULTS: Fifteen novel variants in 15 genes were shared by the father and daughter, including a nonsense mutation in REEP5. None of these germline variants were located in tumour regions of LOH shared by the father and daughter. Four genes (EXOG, RANBP2, RANBP6 and TNFRSF1B) harboured missense variants that fell in a region of LOH in the tumour from the father only, but none showed somatic loss of the wild type allele in the tumour. The REEP5 gene was sequenced in 23 individuals with presumed sporadic AMTs or PMP; no LoF or rare missense germline variants were identified. CONCLUSION: Germline exome sequencing of a father and daughter with AMTs identified novel candidate predisposing genes. Further studies are required to clarify the role of these genes in familial AMTs.

Pelvic Exenteration for Anal and Urogenital Squamous Cell Carcinoma: Experience and Outcomes from an Exenteration Unit Over 12 Years.

BACKGROUND: Pelvic exenteration has increasingly been shown to improve disease-free and overall survival for patients with locally advanced pelvic malignancies. Squamous cell carcinoma (SCC) is the second most common pelvic malignancy requiring exenteration. OBJECTIVE: The aim of this study was to report the clinical and oncological outcomes from patients treated with pelvic exenteration for anal and urogenital SCC from a single, high-volume unit. METHODS: A review of a prospectively maintained database from 1991 to 2018 at a high-volume specialised institution was performed. Primary endpoints included R0 resection rates, local recurrence and overall survival (OS) rates. RESULTS: From January 1999 to July 2018, 361 patients underwent pelvic exenteration of which 31 patients were identified with SCC (15 anal SCC, 16 urogenital SCC). The majority of patients were females (n = 24, 77.4%). Median age was 59 (range 35-81). Twenty-seven patients underwent resection with curative intent with an R0 resection rate of 81.5%. Four patients underwent a palliative procedure [R1 = 3 (8%), R2 = 1 (3.3%)]. Mean hospital length of stay was 32 days (range 8-122 days). Disease-free survival was significantly increased in anal SCC with no significant difference in OS compared to urogenital SCC (p = 0.03, p = 0.447 respectively). Advanced pathological T stage was associated with decreased OS (p = 0.023). In the curative intent group the disease-free survival and OS rate was 59.3% and 70% at 24 months, respectively. CONCLUSION: Complete R0 resection is achievable in a high proportion of patients. Urogenital SCC is associated with significantly worse disease-free survival, and advanced T-stage was a significant prognostic factor for OS.

Evolution of pelvic exenteration surgery- resectional trends and survival outcomes over three decades.

OBJECTIVE: To examine the changes in exenterative surgery over three decades analysing oncological outcomes and whether changes in surgical approach have led to improved patient outcomes. BACKGROUND: Advances in surgical technology, perioperative care and pattern of disease recurrence have coincided with an evolutionary change in exenterative surgery. METHODS: A review of a prospectively maintained databases of pelvic exenteration surgery from 1988 to 2018  at two high volume specialised institutions. The total cohort was divided into three major time points (1988-2004, 2005-2010 and 2011 to 2018) to allow comparative analysis. Primary endpoints were overall survival in primary and recurrent disease at each time point. Secondary endpoints included anastomotic leak, blood transfusion, ileus, wound infection rates and evolution of case complexity. Data were analysed using R with a p < 0.05 considered significant. RESULTS: Six hundred and seventy patients underwent exenterative surgery. In 2011-2018 there was an increase in resection of recurrent malignancy with a continuous increase in GI malignancies resected over each time period(p < 0.001,<0.01) and a reduction in gynaecological malignancy(p < 0.001). A significant increase in sacrectomy, pelvic sidewall resection and ileal conduit reconstruction was observed (p < 0.01,<0.001).In 2005-2010 patients had increased rates of ileus and anastomotic leak(p < 0.05). Patients undergoing resection for primary disease had improved overall survival at time points 1988-2004 and 2011-2018 compared to those with recurrent disease(p = 0.007,<0.001). Overall survival was significantly improved in patients with primary versus recurrent disease(p = 0.022). CONCLUSION: There has been a significant improvement in survival in patients undergoing pelvic exenteration surgery from primary disease. Case complexity has increased without significant morbidity.

Outcomes and prognostic factors of multimodality treatment for locally recurrent rectal cancer with curative intent.

PURPOSE: Radical management of locally recurrent rectal cancer (LRRC) can lead to prolonged survival. This study aims to assess outcomes and identify prognostic factors for patients with LRRC treated using a multimodality treatment protocol. METHODS: An analysis of a prospectively maintained institutional database of consecutive patients who underwent radical surgical resection for LRRC was performed. Potential prognostic factors were investigated using a Cox proportional hazards model. RESULTS: Ninety-eight patients were included in this study. A multimodality approach was taken in the majority, including preoperative chemoradiation (78%), intraoperative radiation therapy (47%) and adjuvant chemotherapy (41%). Extended resection was performed where required: bone resection (34%) and lateral pelvic sidewall dissection (31%). The rate of R0 resection was 66%. Estimated rates of 5-year overall survival (OS) and progression-free survival (PFS) were 41.8% (95% CI 32.5-53.7) and 22.5% (95% CI 15.3-33.1). On multivariate analysis, stage III disease at initial primary surgery, a positive margin at initial primary surgery, synchronous or previously resected oligometastases, a lateral or sacral invasive-type pelvic recurrence and the requirement for IORT all predicted for inferior PFS (p < 0.05). Eleven percent of patients subsequently underwent further pelvic surgery for pelvic re-recurrence and had an estimated 5-year OS rate of 54.5% (95% CI 29.0-100.0) from repeat surgery. CONCLUSIONS: Radical multimodality management of LRRC leads to prolonged survival in approximately 40% of patients. Those with sacral or lateral invasive-type recurrence or oligometastatic disease have inferior outcomes and further research is needed to optimise treatment for these groups.

An International Collaborative Standardizing a Comprehensive Patient-Centered Outcomes Measurement Set for Colorectal Cancer.

IMPORTANCE: Global health systems are shifting toward value-based care in an effort to drive better outcomes in the setting of rising health care costs. This shift requires a common definition of value, starting with the outcomes that matter most to patients. OBJECTIVE: The International Consortium for Health Outcomes Measurement (ICHOM), a nonprofit initiative, was formed to define standard sets of outcomes by medical condition. In this article, we report the efforts of ICHOM's working group in colorectal cancer. EVIDENCE REVIEW: The working group was composed of multidisciplinary oncology specialists in medicine, surgery, radiation therapy, palliative care, nursing, and pathology, along with patient representatives. Through a modified Delphi process during 8 months (July 8, 2015 to February 29, 2016), ICHOM led the working group to a consensus on a final recommended standard set. The process was supported by a systematic PubMed literature review (1042 randomized clinical trials and guidelines from June 3, 2005, to June 3, 2015), a patient focus group (11 patients with early and metastatic colorectal cancer convened during a teleconference in August 2015), and a patient validation survey (among 276 patients with and survivors of colorectal cancer between October 15, 2015, and November 4, 2015). FINDINGS: After consolidating findings of the literature review and focus group meeting, a list of 40 outcomes was presented to the WG and underwent voting. The final recommendation includes outcomes in the following categories: survival and disease control, disutility of care, degree of health, and quality of death. Selected case-mix factors were recommended to be collected at baseline to facilitate comparison of results across treatments and health care professionals. CONCLUSIONS: A standardized set of patient-centered outcome measures to inform value-based health care in colorectal cancer was developed. Pilot efforts are under way to measure the standard set among members of the working group.

Primary squamous cell carcinoma of the rectum: An update and implications for treatment.

AIM: To provide an update on the aetiology, pathogenesis, diagnosis, staging and management of rectal squamous cell carcinoma (SCC). METHODS: A systematic review was conducted according to the preferred reporting items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of Ovid MEDLINE was performed with the reference list of selected articles reviewed to ensure all relevant publications were captured. The search strategy was limited to the English language, spanning from 1946 to 2015. A qualitative analysis was undertaken examining patient demographics, clinical presentation, diagnosis, staging, treatment and outcome. The quantitaive analysis was limited to data extracted on treatment and outcomes including radiological, clinical and pathological complete response where available. The narrative and quantitative review were synthesised in concert. RESULTS: The search identified 487 articles in total with 79 included in the qualitative review. The quantitative analysis involved 63 articles, consisting of 43 case reports and 20 case series with a total of 142 individual cases. The underlying pathogenesis of rectal SCC while unclear, continues to be defined, with increasing evidence of a metaplasia-dysplasia-carcinoma sequence and a possible role for human papilloma virus in this progression. The presentation is similar to rectal adenocarcinoma, with a diagnosis confirmed by endoscopic biopsy. Many presumed rectal SCC's are in fact an extension of an anal SCC, and cytokeratin markers are a useful adjunct in this distinction. Staging is most accurately reflected by the tumour-node-metastasis classification for rectal adenocarcinoma. It involves examining locoregional disease by way of magnetic resonance imaging and/or endorectal ultrasound, with systemic spread excluded by way of computed tomography. Positron emission tomography is integral in the workup to exclude an external site of primary SCC with metastasis to the rectum. While the optimal treatment remains as yet undefined, recent studies have demonstrated a global shift away from surgery towards definitive chemoradiotherapy as primary treatment. Pooled overall survival was calculated to be 86% in patients managed with chemoradiation compared with 48% for those treated traditionally with surgery. Furthermore, local recurrence and metastatic rates were 25% vs 10% and 30% vs 13% for the chemoradiation vs conventional treatment cohorts. CONCLUSION: The changing paradigm in the treatment of rectal SCC holds great promise for improved outcomes in this rare disease.

Relative Value of Restaging MRI, CT, and FDG-PET Scan After Preoperative Chemoradiation for Rectal Cancer.

BACKGROUND: Management of rectal cancer has become multidisciplinary and is driven by the stage of the disease, with increased focus on restaging rectal cancer after neoadjuvant therapy. OBJECTIVE: The purpose of this study was to assess the relative impact of restaging after preoperative chemoradiation with FDG-PET scan, CT, and MRI in the management of patients with rectal cancer. DESIGN: This was a retrospective study from a single institution. SETTINGS: This study was conducted at a tertiary cancer center. PATIENTS: A total of 199 patients met the inclusion criteria: patients with rectal adenocarcinoma; staged with positron emission tomography, CT, and MRI; T2 to T4, N0 to N2, M0 to M1; treated with neoadjuvant chemoradiation 50.4 Gy and infusional 5-fluorouracil; and restaged 4 weeks after chemoradiation before surgery between 2003 and 2013. MAIN OUTCOME MEASURES: Comparisons of the tumor stage among different imaging modalities before and after neoadjuvant chemoradiation were performed. The impact of restaging on the management plan was assessed. RESULTS: The stage at presentation was T2, 8.04%; T3, 65.33%; T4, 26.63%; N0, 17.09%; N1, 47.74%; N2, 34.67%; M0, 81.91%; and M1, 18.09%. Changes in disease stage postneoadjuvant chemoradiation were observed in 99 patients (50%). The management plans of 29 patients (15%) were changed. The impact of each restaging modality on management for all of the patients was positron emission tomography, 11%; CT, 4%; and MRI, 4%. In patients with metastatic disease at primary staging, the relative impact of each restaging modality in changing management was positron emission tomography, 32%; CT, 18%; and MRI, 6%. LIMITATIONS: This study was limited by its single-center and retrospective design. Operations were performed 4 weeks after restaging. CONCLUSIONS: Changes in the extent of disease after long-course chemoradiotherapy result in changes of management in a significant percentage of patients. Positron emission tomography has the most significant impact in the change of management overall, and its use in restaging advanced rectal cancer should be further explored.

The Outcomes and Patterns of Treatment Failure After Surgery for Locally Recurrent Rectal Cancer.

OBJECTIVE: To assess the outcomes and patterns of treatment failure of patients who underwent pelvic exenteration surgery for recurrent rectal cancer. BACKGROUND: Despite advances in the management of rectal cancer, local recurrence still occurs. For appropriately selected patients, pelvic exenteration surgery can achieve long-term disease control. METHODS: Prospectively maintained databases of 5 high volume institutions for pelvic exenteration surgery were reviewed and data combined. We assessed the combined endpoints of overall 5-year survival, cancer-specific 5-year mortality, local recurrence, and the development of metastatic disease. RESULTS: Five hundred thirty-three patients who had undergone surgery for locally recurrent rectal cancer were identified. Five-year cancer-specific survival for patients with a complete (R0) resection is 44%, which was achieved in 59% of patients. For those with R1 and R2 resections, the 5-year survival was 26% and 10%, respectively. Radical resection required sacrectomy in 170 patients (32%), and total cystectomy in 105 patients (20%). Treatment failure included local recurrence alone in 75 patients (14%) and systemic metastases with or without local recurrence in 226 patients (42%). Chemoradiotherapy before exenteration was associated with a significant (P < 0.05) improvement in overall 5-year cancer-specific survival for those patients with an R0 resection. Postoperative chemotherapy did not alter outcomes. CONCLUSIONS: R0 resection of the pelvic recurrence is the most significant factor affecting overall and disease-free survival. The surgery is complex and often highly morbid, and where possible patients should be given perioperative chemoradiotherapy. Further investigations are required to determine the role of adjuvant chemotherapy.

Peritoneal Tumorigenesis and Inflammation are Ameliorated by Humidified-Warm Carbon Dioxide Insufflation in the Mouse.

BACKGROUND: Conventional laparoscopic surgery uses CO2 that is dry and cold, which can damage peritoneal surfaces. It is speculated that disseminated cancer cells may adhere to such damaged peritoneum and metastasize. We hypothesized that insufflation using humidified-warm CO2, which has been shown to reduce mesothelial damage, will also ameliorate peritoneal inflammation and tumor cell implantation compared to conventional dry-cold CO2. METHODS: Laparoscopic insufflation was modeled in mice along with anesthesia and ventilation. Entry and exit ports were introduced to maintain insufflation using dry-cold or humidified-warm CO2 with a constant flow and pressure for 1 h; then 1000 or 1 million fluorescent-tagged murine colorectal cancer cells (CT26) were delivered into the peritoneal cavity. The peritoneum was collected at intervals up to 10 days after the procedure to measure inflammation, mesothelial damage, and tumor burden using fluorescent detection, immunohistochemistry, and scanning electron microscopy. RESULTS: Rapid temperature control was achieved only in the humidified-warm group. Port-site tumors were present in all mice. At 10 days, significantly fewer tumors on the peritoneum were counted in mice insufflated with humidified-warm compared to dry-cold CO2 (p < 0.03). The inflammatory marker COX-2 was significantly increased in the dry-cold compared to the humidified-warm cohort (p < 0.01), while VEGFA expression was suppressed only in the humidified-warm cohort. Significantly less mesothelial damage and tumor cell implantation was evident from 2 h after the procedure in the humidified-warm cohort. CONCLUSIONS: Mesothelial cell damage and inflammation are reduced by using humidified-warm CO2 for laparoscopic oncologic surgery and may translate to reduce patients' risk of developing peritoneal metastasis.