Brain parcellation choice affects disease-related topology differences increasingly from global to local network levels

Network-based analyses of deviant brain function have become extremely popular in psychiatric neuroimaging. Underpinning brain network analyses is the selection of appropriate regions of interest (ROIs). Although ROI selection is fundamental in network analysis, its impact on detecting disease effects remains unclear. We investigated the impact of parcellation choice when comparing results from different studies. We investigated the effects of anatomical (AAL) and literature-based (Dosenbach) parcellation schemes on comparability of group differences in 35 female patients with anorexia nervosa and 35 age- and sex-matched healthy controls. Global and local network properties, including network-based statistics (NBS), were assessed on resting state functional magnetic resonance imaging data obtained at 3T. Parcellation schemes were comparably consistent on global network properties, while NBS and local metrics differed in location, but not metric type. Location of local metric alterations varied for AAL (parietal and cingulate cortices) versus Dosenbach (insula, thalamus) parcellation approaches. However, consistency was observed for the occipital cortex. Patient-specific global network properties can be robustly observed using different parcellation schemes, while graph metrics characterizing impairments of individual nodes vary considerably. Therefore, the impact of parcellation choice on specific group differences varies depending on the level of network organization.

Weight restoration therapy rapidly reverses cortical thinning in anorexia nervosa: A longitudinal study

Structural magnetic resonance imaging studies have documented reduced gray matter in acutely ill patients with anorexia nervosa to be at least partially reversible following weight restoration. However, few longitudinal studies exist and the underlying mechanisms of these structural changes are elusive. In particular, the relative speed and completeness of brain structure normalization during realimentation remain unknown. Here we report from a structural neuroimaging study including a sample of adolescent/young adult female patients with acute anorexia nervosa (n=47), long-term recovered patients (n=34), and healthy controls (n=75). The majority of acutely ill patients were scanned longitudinally (n=35): at the beginning of standardized weight restoration therapy and again after partial weight normalization (>10% body mass index increase). High-resolution structural images were processed and analyzed with the longitudinal stream of FreeSurfer software to test for changes in cortical thickness and volumes of select subcortical regions of interest. We found globally reduced cortical thickness in acutely ill patients to increase rapidly (0.06 mm/month) during brief weight restoration therapy (≈3 months). This significant increase was predicted by weight restoration alone and could not be ascribed to potentially mediating factors such as duration of illness, hydration status, or symptom improvements. By comparing cortical thickness in partially weight-restored patients with that measured in healthy controls, we confirmed that cortical thickness had normalized already at follow-up. This pattern of thinning in illness and rapid normalization during weight rehabilitation was largely mirrored in subcortical volumes. Together, our findings indicate that structural brain insults inflicted by starvation in anorexia nervosa may be reversed at a rate much faster than previously thought if interventions are successful before the disorder becomes chronic. This provides evidence drawing previously speculated mechanisms such as (de-)hydration and neurogenesis into question and suggests that neuronal and/or glial remodeling including changes in macromolecular content may underlie the gray matter alterations observed in anorexia nervosa.

Abnormal functional global and local brain connectivity in female patients with anorexia nervosa

BACKGROUND

Previous resting-state functional connectivity studies in patients with anorexia nervosa used independent component analysis or seed-based connectivity analysis to probe specific brain networks. Instead, modelling the entire brain as a complex network allows determination of graph-theoretical metrics, which describe global and local properties of how brain networks are organized and how they interact.

METHODS

To determine differences in network properties between female patients with acute anorexia nervosa and pairwise matched healthy controls, we used resting-state fMRI and computed well-established global and local graph metrics across a range of network densities.

RESULTS

Our analyses included 35 patients and 35 controls. We found that the global functional network structure in patients with anorexia nervosa is characterized by increases in both characteristic path length (longer average routes between nodes) and assortativity (more nodes with a similar connectedness link together). Accordingly, we found locally decreased connectivity strength and increased path length in the posterior insula and thalamus.

LIMITATIONS

The present results may be limited to the methods applied during preprocessing and network construction.

CONCLUSION

We demonstrated anorexia nervosa-related changes in the network configuration for, to our knowledge, the first time using resting-state fMRI and graph-theoretical measures. Our findings revealed an altered global brain network architecture accompanied by local degradations indicating wide-scale disturbance in information flow across brain networks in patients with acute anorexia nervosa. Reduced local network efficiency in the thalamus and posterior insula may reflect a mechanism that helps explain the impaired integration of visuospatial and homeostatic signals in patients with this disorder, which is thought to be linked to abnormal representations of body size and hunger.

Brain structure and function correlates of cognitive subtypes in schizophrenia

Stable neuropsychological deficits may provide a reliable basis for identifying etiological subtypes of schizophrenia. The aim of this study was to identify clusters of individuals with schizophrenia based on dimensions of neuropsychological performance, and to characterize their neural correlates. We acquired neuropsychological data as well as structural and functional magnetic resonance imaging from 129 patients with schizophrenia and 165 healthy controls. We derived eight cognitive dimensions and subsequently applied a cluster analysis to identify possible schizophrenia subtypes. Analyses suggested the following four cognitive clusters of schizophrenia: (1) Diminished Verbal Fluency, (2) Diminished Verbal Memory and Poor Motor Control, (3) Diminished Face Memory and Slowed Processing, and (4) Diminished Intellectual Function. The clusters were characterized by a specific pattern of structural brain changes in areas such as Wernicke's area, lingual gyrus and occipital face area, and hippocampus as well as differences in working memory-elicited neural activity in several fronto-parietal brain regions. Separable measures of cognitive function appear to provide a method for deriving cognitive subtypes meaningfully related to brain structure and function. Because the present study identified brain-based neural correlates of the cognitive clusters, the proposed groups of individuals with schizophrenia have some external validity.

Elevated cognitive control over reward processing in recovered female patients with anorexia nervosa

BACKGROUND

Individuals with anorexia nervosa are thought to exert excessive self-control to inhibit primary drives.

METHODS

This study used functional MRI (fMRI) to interrogate interactions between the neural correlates of cognitive control and motivational processes in the brain reward system during the anticipation of monetary reward and reward-related feedback. In order to avoid confounding effects of undernutrition, we studied female participants recovered from anorexia nervosa and closely matched healthy female controls. The fMRI analysis (including node-to-node functional connectivity) followed a region of interest approach based on models of the brain reward system and cognitive control regions implicated in anorexia nervosa: the ventral striatum, medial orbitofrontal cortex (mOFC) and dorsolateral prefrontal cortex (DLPFC).

RESULTS

We included 30 recovered patients and 30 controls in our study. There were no behavioural differences and no differences in hemodynamic responses of the ventral striatum and the mOFC in the 2 phases of the task. However, relative to controls, recovered patients showed elevated DLPFC activity during the anticipation phase, failed to deactivate this region during the feedback phase and displayed greater functional coupling between the DLPFC and mOFC. Recovered patients also had stronger associations than controls between anticipation-related DLPFC responses and instrumental responding.

LIMITATIONS

The results we obtained using monetary stimuli might not generalize to other forms of reward.

CONCLUSION

Unaltered neural responses in ventral limbic reward networks but increased recruitment of and connectivity with lateral-frontal brain circuitry in recovered patients suggests an elevated degree of selfregulatory processes in response to rewarding stimuli. An imbalance between brain systems subserving bottom-up and top-down processes may be a trait marker of the disorder.

Temporal delay discounting in acutely ill and weight-recovered patients with anorexia nervosa

BACKGROUND

Patients with anorexia nervosa (AN) are characterized by a very low body weight but readily give up immediate rewards (food) for long-term goals (slim figure), which might indicate an unusual level of self-control. This everyday clinical observation may be quantifiable in the framework of the anticipation-discounting dilemma.

METHOD

Using a cross-sectional design, this study compared the capacity to delay reward in 34 patients suffering from acute AN (acAN), 33 weight-recovered AN patients (recAN) and 54 healthy controls. We also used a longitudinal study to reassess 21 acAN patients after short-term weight restoration. A validated intertemporal choice task and a hyperbolic model were used to estimate temporal discounting rates.

RESULTS

Confirming the validity of the task used, decreased delay discounting was associated with age and low self-reported impulsivity. However, no group differences in key measures of temporal discounting of monetary rewards were found.

CONCLUSIONS

Increased cognitive control, which has been suggested as a key characteristic of AN, does not seem to extend the capacity to wait for delayed monetary rewards. Differences between our study and the only previous study reporting decreased delay discounting in adult AN patients may be explained by the different age range and chronicity of acute patients, but the fact that weight recovery was not associated with changes in discount rates suggests that discounting behavior is not a trait marker in AN. Future studies using paradigms with disorder-specific stimuli may help to clarify the role of delay discounting in AN.

Global cortical thinning in acute anorexia nervosa normalizes following long-term weight restoration

BACKGROUND

Anorexia nervosa (AN) is a serious eating disorder characterized by self-starvation, extreme weight loss, and alterations in brain structure. Structural magnetic resonance imaging studies have documented brain volume reductions in acute AN, but it is unclear whether they are 1) regionally specific, or 2) reversible following weight restoration. Here, we measured cortical thickness (CT) for the first time in AN.

METHODS

Structural magnetic resonance imaging data were acquired from adolescent and young adult female patients with acute AN (n = 40), recovered patients following long-term weight restoration (n = 34), and an equal number of age-matched healthy control subjects. Group differences in CT were tested with well-validated procedures implemented in FreeSurfer. The mediating role of clinical variables including body mass index and drive for thinness were explored. For completeness, we also used FreeSurfer's subcortical segmentation stream to test group differences in volumes of select gray matter regions of interest.

RESULTS

Vertex-wise analyses revealed significant thinning of over 85% of the cortical surface in patients with acute AN and CT normalization in recovered patients following long-term weight restoration, although normal age-related trajectories were absent in the disorder. This pattern of results was largely mirrored in subcortical volumes. We also observed a strong negative correlation between CT and drive for thinness in extrastriate regions involved in body perception.

CONCLUSIONS

Structural brain anomalies in AN as expressed in CT and subcortical volume are primarily the consequence of malnutrition and unlikely to reflect premorbid trait markers or permanent scars, but longitudinal data are needed.

Reduced functional connectivity in the thalamo-insular subnetwork in patients with acute anorexia nervosa

The neural underpinnings of anorexia nervosa (AN) are poorly understood. Results from existing functional brain imaging studies using disorder-relevant food- or body-stimuli have been heterogeneous and may be biased due to varying compliance or strategies of the participants. In this study, resting state functional connectivity imaging was used. To explore the distributed nature and complexity of brain function we characterized network patterns in patients with acute AN. Thirty-five unmedicated female acute AN patients and 35 closely matched healthy female participants underwent resting state functional magnetic resonance imaging. We used a network-based statistic (NBS) approach [Zalesky et al., 2010a] to identify differences between groups by isolating a network of interconnected nodes with a deviant connectivity pattern. Group comparison revealed a subnetwork of connections with decreased connectivity including the amygdala, thalamus, fusiform gyrus, putamen and the posterior insula as the central hub in the patient group. Results were not driven by changes in intranodal or global connectivity. No network could be identified where AN patients had increased coupling. Given the known involvement of the identified thalamo-insular subnetwork in interoception, decreased connectivity in AN patients in these nodes might reflect changes in the propagation of sensations that alert the organism to urgent homeostatic imbalances and pain-processes that are known to be severely disturbed in AN and might explain the striking discrepancy between patient's actual and perceived internal body state.

Prefrontal inefficiency is associated with polygenic risk for schizophrenia

Considering the diverse clinical presentation and likely polygenic etiology of schizophrenia, this investigation examined the effect of polygenic risk on a well-established intermediate phenotype for schizophrenia. We hypothesized that a measure of cumulative genetic risk based on additive effects of many genetic susceptibility loci for schizophrenia would predict prefrontal cortical inefficiency during working memory, a brain-based biomarker for the disorder. The present study combined imaging, genetic and behavioral data obtained by the Mind Clinical Imaging Consortium study of schizophrenia (n = 255). For each participant, we derived a polygenic risk score (PGRS), which was based on over 600 nominally significant single nucleotide polymorphisms, associated with schizophrenia in a separate discovery sample comprising 3322 schizophrenia patients and 3587 control participants. Increased polygenic risk for schizophrenia was associated with neural inefficiency in the left dorsolateral prefrontal cortex after covarying for the effects of acquisition site, diagnosis, and population stratification. We also provide additional supporting evidence for our original findings using scores based on results from the Psychiatric Genomics Consortium study. Gene ontology analysis of the PGRS highlighted genetic loci involved in brain development and several other processes possibly contributing to disease etiology. Our study permits new insights into the additive effect of hundreds of genetic susceptibility loci on a brain-based intermediate phenotype for schizophrenia. The combined impact of many common genetic variants of small effect are likely to better reveal etiologic mechanisms of the disorder than the study of single common genetic variants.

Serum brain-derived neurotrophic factor and cognitive functioning in underweight, weight-recovered and partially weight-recovered females with anorexia nervosa

Several studies support the assumption that the brain-derived neurotrophic factor (BDNF) plays an important role in the pathophysiology of eating disorders. In the present cross-sectional and longitudinal study, we investigated BDNF levels in patients with anorexia nervosa (AN) at different stages of their illness and the association with cognitive functioning. We measured serum BDNF in 72 acutely underweight female AN patients (acAN), 23 female AN patients who successfully recovered from their illness (recAN), and 52 healthy control women (HCW). Longitudinally, 30 acAN patients were reassessed after short-term weight gain. The association between BDNF levels and psychomotor speed was investigated using the Trail Making Test. BDNF serum concentrations were significantly higher in recAN participants if compared to acAN patients and increased with short-term weight gain. In acAN patients, but not HCW, BDNF levels were inversely associated with psychomotor speed. AcAN patients with higher BDNF levels also had lower life time body mass indexes. Taken together, our results indicate that serum BDNF levels in patients with AN vary with the stage of illness. Based on the pleiotropic functions of BDNF, changing levels of this neurotrophin may have different context-dependent effects, one of which may be the modulation of cognitive functioning in acutely underweight patients.

Increased resting state functional connectivity in the fronto-parietal and default mode network in anorexia nervosa

The etiology of anorexia nervosa (AN) is poorly understood. Results from functional brain imaging studies investigating the neural profile of AN using cognitive and emotional task paradigms are difficult to reconcile. Task-related imaging studies often require a high level of compliance and can only partially explore the distributed nature and complexity of brain function. In this study, resting state functional connectivity imaging was used to investigate well-characterized brain networks potentially relevant to understand the neural mechanisms underlying the symptomatology and etiology of AN. Resting state functional magnetic resonance imaging data was obtained from 35 unmedicated female acute AN patients and 35 closely matched healthy controls female participants (HC) and decomposed using spatial group independent component analyses (ICA). Using validated templates, we identified components covering the fronto-parietal “control” network, the default mode network (DMN), the salience network, the visual and the sensory-motor network. Group comparison revealed an increased functional connectivity between the angular gyrus and the other parts of the fronto-parietal network in patients with AN in comparison to HC. Connectivity of the angular gyrus was positively associated with self-reported persistence in HC. In the DMN, AN patients also showed an increased functional connectivity strength in the anterior insula in comparison to HC. Anterior insula connectivity was associated with self-reported problems with interoceptive awareness. This study, with one of the largest sample to date, shows that acute AN is associated with abnormal brain connectivity in two major resting state networks (RSN). The finding of an increased functional connectivity in the fronto-parietal network adds novel support for the notion of AN as a disorder of excessive cognitive control, whereas the elevated functional connectivity of the anterior insula with the DMN may reflect the high levels of self- and body-focused ruminations when AN patients are at rest.

Associations of white matter integrity and cortical thickness in patients with schizophrenia and healthy controls

Typical brain development includes coordinated changes in both white matter (WM) integrity and cortical thickness (CT). These processes have been shown to be disrupted in schizophrenia, which is characterized by abnormalities in WM microstructure and by reduced CT. The aim of this study was to identify patterns of association between WM markers and cortex-wide CT in healthy controls (HCs) and patients with schizophrenia (SCZ). Using diffusion tensor imaging and structural magnetic resonance imaging data of the Mind Clinical Imaging Consortium study (130 HC and 111 SCZ), we tested for associations between (a) fractional anisotropy in selected manually labeled WM pathways (corpus callosum, anterior thalamic radiation, and superior longitudinal fasciculus) and CT, and (b) the number of lesion-like WM regions ("potholes") and CT. In HC, but not SCZ, we found highly significant negative associations between WM integrity and CT in several pathways, including frontal, temporal, and occipital brain regions. Conversely, in SCZ the number of WM potholes correlated with reduced CT in the left lateral temporal gyrus, left fusiform, and left lateral occipital brain area. Taken together, we found differential patterns of association between WM integrity and CT in HC and SCZ. Although the pattern in HC can be explained from a developmental perspective, the reduced gray matter CT in SCZ patients might be the result of focal but spatially heterogeneous disruptions of WM integrity.

Smoking status as a potential confounder in the study of brain structure in schizophrenia

Several but not all MRI studies have reported volume reductions in the hippocampus and dorsolateral prefrontal cortex (DLPFC) in patients with schizophrenia. Given the high prevalence of smoking among schizophrenia patients and the fact that smoking has also been associated with alterations in brain morphology, this study evaluated whether a proportion of the known gray matter reductions in key brain regions may be attributed to smoking rather than to schizophrenia alone. We examined structural MRI data of 112 schizophrenia patients (53 smokers and 59 non-smokers) and 77 healthy non-smoker controls collected by the MCIC study of schizophrenia. An automated atlas based probabilistic method was used to generate volumetric measures of the hippocampus and DLPFC. The two patient groups were matched with respect to demographic and clinical variables. Smoker schizophrenia patients showed significantly lower hippocampal and DLPFC volumes than non-smoker schizophrenia patients. Gray matter volume reductions associated with smoking status ranged between 2.2% and 2.8%. Furthermore, we found significant volume differences between smoker patients and healthy controls in the hippocampus and DLPFC, but not between non-smoker patients and healthy controls. Our data suggest that a proportion of the volume reduction seen in the hippocampus and DLPFC in schizophrenia is associated with smoking rather than with the diagnosis of schizophrenia. These results may have important implications for brain imaging studies comparing schizophrenia patients and other groups with a lower smoking prevalence.

The impact of genome-wide supported schizophrenia risk variants in the neurogranin gene on brain structure and function

The neural mechanisms underlying genetic risk for schizophrenia, a highly heritable psychiatric condition, are still under investigation. New schizophrenia risk genes discovered through genome-wide association studies (GWAS), such as neurogranin (NRGN), can be used to identify these mechanisms. In this study we examined the association of two common NRGN risk single nucleotide polymorphisms (SNPs) with functional and structural brain-based intermediate phenotypes for schizophrenia. We obtained structural, functional MRI and genotype data of 92 schizophrenia patients and 114 healthy volunteers from the multisite Mind Clinical Imaging Consortium study. Two schizophrenia-associated NRGN SNPs (rs12807809 and rs12541) were tested for association with working memory-elicited dorsolateral prefrontal cortex (DLPFC) activity and surface-wide cortical thickness. NRGN rs12541 risk allele homozygotes (TT) displayed increased working memory-related activity in several brain regions, including the left DLPFC, left insula, left somatosensory cortex and the cingulate cortex, when compared to non-risk allele carriers. NRGN rs12807809 non-risk allele (C) carriers showed reduced cortical gray matter thickness compared to risk allele homozygotes (TT) in an area comprising the right pericalcarine gyrus, the right cuneus, and the right lingual gyrus. Our study highlights the effects of schizophrenia risk variants in the NRGN gene on functional and structural brain-based intermediate phenotypes for schizophrenia. These results support recent GWAS findings and further implicate NRGN in the pathophysiology of schizophrenia by suggesting that genetic NRGN risk variants contribute to subtle changes in neural functioning and anatomy that can be quantified with neuroimaging methods.

Single incision laparoscopic colorectal surgery: a single surgeon experience of 102 consecutive cases

BACKGROUND

Due to the recent heightened interest in even less invasive surgery, single port laparoscopic colorectal surgery is quickly gaining acceptance. While this access technique was first described in 2007 for colorectal resective procedures, large series are lacking.

METHODS

Between January 2009 and October 2010, all patients undergoing single port colorectal surgery performed by a single surgeon were prospectively entered into an IRB-approved database and studied with regard to perioperative events, morbidity, and mortality.

RESULTS

One hundred and two consecutive patients underwent a single port colorectal procedure. Mean age was 47 years (9-93 years), and average body mass index was 26 kg/m(2) (15-39 kg/m(2)). Primary diagnoses included ulcerative colitis (51), neoplasia (23), Crohn's disease (14), diverticulitis (11), familial adenomatous polyposis (1), and other (2). Procedures included 23 total colectomies, 40 segmental colectomies, and 19 other procedures. There was 1 conversion to an open operation, and 18 (18%) patients required placement of additional ports (1 port: N = 13; 2 ports: N = 2; 3 ports: N = 3). Average operating room time was 99 min (13-245), mean length of incision was 3.7 cm (1.2-7.8 cm), and average estimated blood loss was 140 ml (0-750 ml). There was one postoperative death, and 39 (38%) patients experienced minor postoperative complications. Mean lymph node harvest for oncologic resections was 44 (14-142). The average length of hospital stay was 5.9 days (2-24 days).

CONCLUSIONS

With proper patient selection and laparoscopic experience, single port colorectal surgery can be performed for even the most complex colorectal procedures. Further studies are needed to assess the benefits that single port colorectal surgery has over a conventional laparoscopic approach.

Minimally invasive surgical wound infections: laparoscopic surgery decreases morbidity of surgical site infections and decreases the cost of wound care

AIM

The morbidity of surgical site infections (SSIs) were compared in patients who underwent open (OS) vs laparoscopic (LS) colorectal surgery.

METHOD

Data from 603 consecutive LS patients and 2246 consecutive OS patients were prospectively recorded. Morbidity of SSIs was assessed by the need for emergency department (ED) evaluation, subsequent hospital re-admission and re-operation. The cost of wound care was measured by the need for home healthcare, wound vacuum assisted closure (VAC) or independent patient wound care.

RESULTS

SSIs were identified in 5.8% (n = 25) of LS patients and 4.8% (n = 65) of OS patients. ED evaluation for the infection was needed in 24% of the LS group and 42% of the OS group. Hospital re-admission was needed in one LS patient and in 52% OS patients. No LS patient needed re-operation compared with 12% of OS patients. HHC ($162/dressing change) was required in 63% of the OS group compared with 8% of LS group. A home wound VAC system ($107/day) was utilized in 12% of the OS patients but in none of the LS patients. Dressing changes were managed independently by the patient in 92% of the LS compared with 37% of the OS patients.

CONCLUSION

Laparoscopic colorectal surgery patients experience less morbidity when they develop SSIs incurring less cost compared with open colorectal surgery patients.

Outcomes after laparoscopic intestinal resection in obese versus non-obese patients

BACKGROUND

The degree of benefit derived from laparoscopic bowel resection in obese compared with non-obese patients is poorly understood.

METHODS

A total of 436 obese patients (body mass index (BMI) at least 30 kg/m(2), mean 34·9 kg/m(2)) who underwent laparoscopic bowel resection during 1992-2008 were identified from a prospective database. An equal number of non-obese patients (mean BMI 24·8 kg/m(2)) was case-matched by age, sex, year of surgery, American Society of Anesthesiologists score, diagnosis and type of operation. Patients with previous major abdominal surgery were excluded. Postoperative morbidity and recovery were compared between obese and non-obese patients.

RESULTS

Mean duration of operation (171·5 versus 157·3 min; P = 0·017), estimated blood loss (EBL; 224·9 versus 164·6 ml; P = 0·001) and conversion rate (13·3 versus 7·1 per cent; P = 0·003) were increased significantly in obese patients. Overall postoperative morbidity was also greater (32·1 versus 25·7 per cent; P = 0·041), particularly wound infection rate (10·6 versus 4·8 per cent; P = 0·002). Among laparoscopically completed operations, obese patients had higher rates of overall morbidity (31·5 versus 24·2 per cent; P = 0·026) and wound infection (10·2 versus 4·4 per cent; P = 0·002). Conversion was associated with increased EBL, intraoperative complications, overall morbidity and length of stay in both groups. The effect of conversion in worsening outcomes was comparable in obese and non-obese patients, except for a greater increase in incision length (11·0 versus 8·0 cm; P = 0·001) and EBL (304·8 versus 89·8 ml; P = 0·001) in obese patients.

CONCLUSION

Laparoscopic bowel resection results in greater morbidity in obese than in non-obese individuals. This difference remains comparable whether the procedure is completed laparoscopically or converted.

Pathologic complete response after neoadjuvant treatment for rectal cancer decreases distant recurrence and could eradicate local recurrence

BACKGROUND

The aim of this study was to evaluate the clinical implications of pathologic complete response (pCR) (i.e., T0N0M0) after neoadjuvant chemoradiation and radical surgery in patients with locally advanced rectal cancer.

MATERIALS AND METHODS

A single-center, prospectively maintained colorectal cancer database was queried for patients with primary cII and cIII rectal cancer staged by CT and ERUS/MRI undergoing long-course neoadjuvant chemoradiation followed by proctectomy with curative intent between 1997 and 2007. Patients were stratified into pCR and no-pCR groups and compared with respect to demographics, tumor and treatment characteristics, and oncologic outcomes. Outcomes evaluated were 5-year overall survival, disease-free survival, disease-specific mortality, local recurrence, and distant recurrence.

RESULTS

The query returned 238 patients (73% male), with a median age of 57 years and median follow-up of 54 months. Of these, 58 patients achieved pCR. Patients with pCR vs no-pCR were statistically comparable with respect to demographics, chemoradiation regimens, tumor distance from anal verge, clinical stage, surgical procedures performed, and follow-up time. No patient with pCR had local recurrence. Overall survival and distant recurrence were also significantly improved for patients achieving pCR.

CONCLUSIONS

Achievement of pCR after neoadjuvant chemoradiation is associated with greatly improved cancer outcomes in locally advanced rectal cancer. Future studies should evaluate the relationship between increases in pCR rates and improvements in cancer outcomes in this population.

Hand-assisted laparoscopic surgery may be a useful tool for surgeons early in the learning curve performing total abdominal colectomy

OBJECTIVE

We evaluated outcomes after hand-assisted (HALC) and straight laparoscopic (LC) techniques for the initial laparoscopic total abdominal colectomy (TAC) procedures performed by surgeons starting their laparoscopic careers.

METHOD

The first eight HALC cases of two surgeons performing TAC by this technique (Group A) were compared with the first (Group B) and last eight (Group C) TAC cases of three surgeons performing LC. Groups A and B were compared with a matched group of open total colectomy cases (Group D) and to the eight cases performed by an experienced surgeon (Group E). Demographics, intra-operative and postoperative outcomes including operation time, morbidity, conversion and readmission rates and length of hospital stay (LOS) were compared using Wilcoxon or Chi-squared tests.

RESULTS

Demographics of the patients were similar. Groups A, B C and E had similar operating time (P = 0.10) which was significantly longer than Group D (P < 0.0001). Morbidity (P = 0.75) and readmission rates were similar (P = 0.89). Conversion rate was significantly higher for Group B (Group B: 41.7%vs Group A: 0%, P = 0.008), in the early period. LOS was comparable between minimally invasive groups but significantly shorter than open surgery group (P = 0.0005). For Groups A and C, operating time (P = 0.55), conversion rate (P = 0.11), morbidity (P = 0.83) and LOS (P = 0.12) were similar.

CONCLUSIONS

Hand-assisted laparoscopic colectomy may be associated with a significantly shorter learning curve for TAC as results are better than early LC and comparable with LC performed by experienced laparoscopic surgeons. It may be a better option for surgeons early in their laparoscopic career.

Downstaging without complete pathologic response after neoadjuvant treatment improves cancer outcomes for cIII but not cII rectal cancers

BACKGROUND

The aim of this study was to evaluate whether downstaging impacts prognosis in patients with cII versus cIII rectal cancer.

MATERIALS AND METHODS

We identified from our colorectal cancer database 295 patients with primary cII and cIII rectal cancer staged by CT and ERUS/MRI who received 5-FU-based chemoradiation followed by R0 surgery after a median interval of 7 weeks during 1997-2007. The median radiotherapy dose was 5040 cGy. We excluded 58 patients with pathologic complete response (pCR) and compared among the remaining 162 patients pathologic downstaging (cII to ypI, cIII to ypII or ypI) versus no pathologic downstaging (c stage < or = yp stage). Outcomes evaluated were 5-year overall survival, 3-year cancer-specific survival, disease-free survival, overall recurrence, local recurrence, and distant recurrence.

RESULTS

The median age was 58 years and median follow-up was 48 months. Patients with downstaging versus no downstaging were statistically comparable with respect to demographics, chemoradiation regimen, interval time between neoadjuvant chemoradiation and surgery, tumor distance from anal verge, surgical procedures performed, and follow-up time. With the exception of local recurrence rates, downstaging resulted in significantly improved cancer outcomes for cIII but not cII.

CONCLUSIONS

Downstaging without pCR is a significant prognostic factor for patients with stage cIII rectal cancer. Tumor response to neoadjuvant chemoradiation should be taken into account when defining the optimal adjuvant chemotherapy regimen for patients with cIII rectal cancer.

Does a laparoscopic approach affect the number of lymph nodes harvested during curative surgery for colorectal cancer?

BACKGROUND

This study aimed to assess the number of lymph nodes (LNs) harvested after laparoscopic and open colorectal cancer resections.

METHODS

Between 1996 and 2007, 431 colorectal cancer patients underwent laparoscopic resection. During the periods of 1996-1997, 2002-2003, and 2006-2007, 243 patients undergoing laparoscopic colorectal cancer resection were matched 1-2 by age, operation, gender, operation date, body mass index (BMI), and tumor stage (TNM) to 486 patients undergoing open surgery. The numbers of examined and involved LNs were compared according to tumor location and year of surgery.

RESULTS

Colorectal cancer resections (243 laparoscopic and 486 open procedures) were performed for 729 patients (447 men) with a mean age of 66.2 +/- 12.3 years and a mean BMI of 28.5 +/- 7.3. The mean number of LNs per case was 24.8 +/- 20.6. The number of LNs retrieved did not differ between laparoscopic and open surgery (p = 0.4). A significant difference was observed between the number of involved LNs retrieved laparoscopically (2.2 +/- 3.8) and the number retrieved by open surgery (1.6 +/- 4; p = 0.03). There were significant differences between the numbers of LNs retrieved from the right colon (28.1 +/- 14.6), left colon (24.5 +/- 17.6), and rectum (19.1 +/- 15.1) (p < 0.001). There were significantly fewer examined LNs in laparoscopic than in open cases during 2002 and 2003 (p = 0.003).

CONCLUSION

Laparoscopic resection of colorectal cancer can achieve lymph node retrieval similar to that achieved by the open approach. In this era of new technology, laparoscopic lymph node harvest is becoming more optimized.

Effect of downstaging without complete pathologic response after neoadjuvant treatment on cancer outcomes for cIII and cII rectal cancers

4108

Background: Neoadjuvant chemoradiation followed by surgery is standard of care for locally advanced rectal cancer. The impact of downstaging on prognosis when pathologic complete response (pCR) cannot be achieved remains unclear. The aim of this study was to evaluate whether downstaging impacts prognosis in patients with cII vs. cIII rectal cancer. Methods: We identified from our colorectal cancer database 233 patients with primary cII and cIII rectal cancer staged by CT and ERUS/MRI who received 5FU-based chemoradiation followed by R0 surgery after a median interval of 7 weeks during 1997–2007. Median radiotherapy dose was 5040 cGy. We excluded 58 patients with pCR and. Compared among the remaining 175 patients pathologic downstaging (cII to ypI, cIII to ypII or ypI) vs. No pathologic downstaging (c stage ≤ yp stage). Outcomes evaluated were 5-year overall survival, 3-year recurrence-free survival, overall recurrence, local recurrence and distant recurrence. Results: Median age was 58 years and median follow-up was 48 months. Patients with cII vs. cIII stage were statistically comparable regarding demographics, chemoradiation regimen, interval to surgery after neoadjuvant treatment, tumor distance from anal verge, operations performed and follow-up. The incidence of downstaging was increased in stage cIII vs. cII patients (68% vs. 21%, p <0.001). With the exception of local recurrence rates, downstaging resulted in significantly improved cancer outcomes for cIII but not cII ( Table ). Conclusions: Downstaging without pCR is a significant prognostic factor for patients with stage cIII rectal cancer. A larger sample size is required to confirm lack of downstaging benefits in stage cII.

[Table: see text]

No significant financial relationships to disclose.