The effect of deprivation and the systemic inflammatory response on outcome following curative resection for colorectal cancer

Gamma-Oryzanol-Rich Fraction from Purple Rice Extract Attenuates Lipopolysaccharide-Stimulated Inflammatory Responses, Migration and VEGFA Production in SW480 Cells via Modulation of TLR4 and NF-κB Pathways

Inflammatory response facilitating colorectal cancer (CRC) progression is a serious event following operative infection, which can occur in CRC patients. This event is mainly mediated by bacterial lipopolysaccharide (LPS), via a toll like receptor 4 (TLR4) and NF-κB. Hexane soluble fraction (HSF) from purple rice extract (PRE) has been identified as a γ-oryzanol (OR)-rich fraction. Recently, HSF possessed inhibitory effect of LPS-stimulated metastasis of human colon cancer SW480 cells, however the related mechanism was unknown. Thus, this study aimed to investigate the effect of HSF on inflammatory response-associated cancer progression of LPS-stimulated SW480 cells. The various inflammatory mediators, vascular endothelial growth factor-A (VEGFA) and related pathways were evaluated by Western blot and ELISA. Furthermore, cell migration was also determined by migration assays. Of all, HSF seemed to be stronger than OR to attenuate the responsiveness of LPS on various inflammatory mediators, which was related to an obvious reduction of cancer cell migration as well as indistinct disruption on VEGFA production in SW480 cells, via downregulation of TLR4 and NF-κB. Therefore, OR-rich fraction from PRE, against the subsequent inflammatory response and CRC progression following surgery, which could be combined with conventional treatments to increase the survival rate.

Lipopolysaccharides increase the risk of colorectal cancer recurrence and metastasis due to the induction of neutrophil extracellular traps after curative resection

BACKGROUND

Intra-abdominal infection after curative surgery for colorectal cancer is a serious complication associated with an increased risk of recurrence. Lipopolysaccharides (LPS)-an essential component of the cell wall of Gram-negative bacteria-were found to exert a protumorigenic effect by stimulating the inflammatory pathology and formation of neutrophil extracellular traps (NETs). This study was conducted to test whether LPS-induced formation of NETs promotes the development of cancer and metastasis.

METHODS

The clinical characteristics, incidence of relapse, and serum myeloperoxidase-DNA complexes of 40 patients with infection and 40 patients without infection after curative surgery were analyzed. The effects of LPS on the induction of NETs were evaluated in a mouse model of colorectal cancer and liver metastasis. The toll-like receptor 9 (TLR9)-a DNA receptor-was knocked down to assess its effect on the mitogen-activated protein kinase pathway and activities implicated in the formation of NETs.

RESULTS

Analysis of the clinical data obtained from these patients showed the significant relation of the formation of NETs and incidence of metastasis and survival rates. Subsequent in vitro experiments revealed an increased level of citrullinated-histone H3 and myeloperoxidase-DNA in LPS-injected mice with colorectal cancer. In the mimic metastatic model, injection of LPS enhanced the metastatic capacity, which was then attenuated by DNase I. This suggested that the formation of NETs was activated by LPS. Injection of TLR9-knockdown HCT116 cells in mice, followed by induction through LPS, mitigated the level of citrullinated-histone H3 and myeloperoxidase-DNA. This finding implied that the formation of NETs was suppressed.

CONCLUSION

These findings shed light on the mechanism underlying the relationship between the elevated rate of colorectal cancer recurrence in patients who underwent surgery and the incidence of infection. This mechanism involves the protumorigenic activities of LPS-induced formation of NETs. The NETs which could be mediated by the TLR9 and the mitogen-activated protein kinase signaling pathway.

Serum cytokine profile as a potential prognostic tool in colorectal cancer patients - one center study

Aim

Comparison of 14 cytokines levels between a control group and prospectively enrolled CRC patients to confirm their significance in CRC development. We tested if a model based on 14 cytokines levels could predict prognosis in Caucasian CRC patients treated with 5-FU based chemotherapy.

Background

Novel prognostic tools in colorectal cancer (CRC) are necessary to optimize treatment, reduce toxicity and chemotherapy (CHT) costs.

Materials and Methods

We assessed prognostic significance of 14 cytokines: IL-1 beta, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL12p70, IL-13, IL-17A in 75 prospectively enrolled CRC patients before initiation of palliative or adjuvant CHT and in 22 control subjects. Readings were taken using the Bio-Plex 200 System. Response to treatment was assessed after 6 months from initiation of CHT. The treated group was divided depending on the response into a progressors (death, progression of disease) and non-progressors group (stable disease, partial response, complete response).

Results

We found that increased concentration of IL-8 was a negative prognostic factor in the whole group and palliative subgroup, whereas increased level of IL-10, IL-7, and IL-12p70 was a negative predictor in the adjuvant group CHT.

Conclusions

We proposed a statistical model based on circulating cytokine levels, showing a good prognostic value in prediction of the response to CHT (AUC = 0.956). The model, including combined IL-2, IL-8, IL-10 and IL-13 levels, established in the whole treated group, should be validated in larger trials.

Increase in the Lipopolysaccharide Activity and Accumulation of Gram-Negative Bacteria in the Stomach With Low Acidity

INTRODUCTION:

Lipopolysaccharides (LPSs) of Gram-negative bacteria (GNB) are highly toxic and induce inflammation. Therefore, we investigated both the LPS activity and composition of GNB in the gastric fluid (GF) to assess the potential toxicity of them accumulated in the stomach.

METHODS:

GF and saliva samples were obtained from 158 outpatients who were undergoing upper gastrointestinal endoscopy and 36 volunteers using a nasogastric tube. The LPS activity was measured by assay kits including recombinant Factor C or Limulus amebocyte lysate. To assess the bacterial composition in the samples, a 16S ribosomal DNA-based operational taxonomic unit analysis was performed. We focused on the genera representing >0.1% of the whole microbiota.

RESULTS:

We found a high LPS activity in the GF samples with weak acidity (approximately > pH 4), whereas little/no activity in those with strong acidity (approximately < pH 2). Spearman test also demonstrated a close correlation between pH and LPS in those samples (r = 0.872). The relative abundance of GNB in the saliva showed no significant difference between the subject groups with weak- and strong-acidity GF. In addition, in the subjects whose GF acidity was weak, the GNB abundance in the GF was almost the same as that in the saliva. By contrast, in the subjects whose GF acidity was strong, the GNB abundance in the GF was significantly lower than that in the saliva.

DISCUSSION:

GNB that have recently moved from the oral cavity might account for the prominent LPS activity in a stomach with weak acidity.

MyD88 Regulates LPS-induced NF-ĸB/MAPK Cytokines and Promotes Inflammation and Malignancy in Colorectal Cancer Cells

BACKGROUND/AIM

Inflammation may play a role in cancer initiation and progression. The molecular mechanisms by which inflammation causes colorectal cancer, remains unclear. The present study investigated a signaling pathway that affects inflammation in colorectal cancer.

MATERIALS AND METHODS

SW480 cells, HCT116 cells, and cells with knockdown of myeloid differentiation 88 (MyD88), and forced expression of MyD88 were treated with lipopolysaccharide (LPS; 1 μg/ml). Inflammation-related mRNA expression was analyzed by the quantitative reverse transcription polymerase chain reaction and inflammatory cytokines were detected by western blotting. The enzyme-linked immunosorbent assay (ELISA) was used to quantify inflammation-related cytokines in colorectal cancer cells. Cancer cell properties were evaluated using the wound-healing assay, transwell migration assay, transwell invasion assay, colony-formation assay, and CCK-8 assay.

RESULTS

LPS up-regulated mRNA and protein levels of inflammatory factors in colorectal cancer cells. Knockdown of MyD88 inhibited LPS-induced mRNA expression and inflammatory protein expression in colorectal cancer cells. Similarly, silencing of MyD88 expression suppressed LPS-induced changes in the biological behavior of colorectal cancer cells. Silencing of MyD88 expression down-regulated expression of proteins of the LPS/nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-ĸB)/mitogen-activated protein kinase (MAPK) signaling pathway. Restoration of the expression of MyD88 reversed the effects in LPS-treated HCT116 cells.

CONCLUSION

MyD88-regulated LPS/NF-ĸB/MAPK signaling pathway affects the inflammatory and biological behavior of LPS-induced colorectal cancer cells.

Systematic review of the influence of socioeconomic deprivation on mortality after colorectal surgery

Background

Socioeconomic deprivation is a potentially important factor influencing surgical outcomes. This systematic review aimed to summarize the evidence for any association between socioeconomic group and mortality after colorectal surgery, and to report the definitions of deprivation used and the approaches taken to adjust for co-morbidity in this patient population.

Methods

MEDLINE, Embase, the Cochrane Library and Web of Science were searched for studies up to November 2016 on adult patients undergoing major colorectal surgery, which reported on mortality according to socioeconomic group. Risk of bias and study quality were assessed by extracting data relating to study size, and variations in inclusion and exclusion criteria. Quality was assessed using a modification of a previously described assessment tool.

Results

The literature search identified 59 studies published between 1993 and 2016, reporting on 2 698 403 patients from eight countries. Overall findings showed evidence for higher mortality in more deprived socioeconomic groups, both in the perioperative period and in the longer term. Studies differed in how they defined socioeconomic groups, but the most common approach was to use one of a selection of multifactorial indices based on small geographical areas. There was no consistent approach to adjusting for co-morbidity but, where this was considered, the Charlson Co-morbidity Index was most frequently used.

Conclusion

This systematic review suggests that socioeconomic deprivation influences mortality after colorectal surgery.

C-Reactive Protein Is an Important Biomarker for Prognosis Tumor Recurrence and Treatment Response in Adult Solid Tumors: A Systematic Review

PURPOSE

A systematic literature review was done to determine the relationship between elevated CRP and prognosis in people with solid tumors. C-reactive protein (CRP) is a serum acute phase reactant and a well-established inflammatory marker. We also examined the role of CRP to predict treatment response and tumor recurrence.

METHODS

MeSH (Medical Subject Heading) terms were used to search multiple electronic databases (PubMed, EMBASE, Web of Science, SCOPUS, EBM-Cochrane). Two independent reviewers selected research papers. We also included a quality Assessment (QA) score. Reports with QA scores <50% were excluded. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) methodology was utilized for this review (S1 PRISMA Checklist).

RESULTS

271 articles were identified for final review. There were 45% prospective studies and 52% retrospective. 264 had intermediate QA score (≥50% but <80%); Seven were adequate (80% -100%); A high CRP was predictive of prognosis in 90% (245/271) of studies-80% of the 245 studies by multivariate analysis, 20% by univariate analysis. Many (52%) of the articles were about gastrointestinal malignancies (GI) or kidney malignancies. A high CRP was prognostic in 90% (127 of 141) of the reports in those groups of tumors. CRP was also prognostic in most reports in other solid tumors primary sites.

CONCLUSIONS

A high CRP was associated with higher mortality in 90% of reports in people with solid tumors primary sites. This was particularly notable in GI malignancies and kidney malignancies. In other solid tumors (lung, pancreas, hepatocellular cancer, and bladder) an elevated CRP also predicted prognosis. In addition there is also evidence to support the use of CRP to help decide treatment response and identify tumor recurrence. Better designed large scale studies should be conducted to examine these issues more comprehensively.

The impact of surgical specialisation on survival following elective colon cancer surgery

PURPOSE

Reorganisation of cancer services in the UK and across Europe has led to elective surgery for colon cancer being increasingly, but not exclusively, delivered by specialist colorectal surgeons. This study examines survival after elective colon cancer surgery performed by specialist compared to non-specialist surgeons.

METHOD

Patients undergoing elective surgery for colon cancer in 16 hospitals between 2001 and 2004 were identified from a prospectively maintained regional audit database. Post-operative mortality (<30 days) and 5-year relative survival in those receiving surgery under the care of a specialist or non-specialist surgeon were compared.

RESULTS

A total of 1,856 patients were included, of which, 1,367 (73.7%) were treated by a specialist and 489 (26.4%) by a non-specialist surgeon. Those treated by a specialist were more likely to be deprived, undergo surgery in a high volume unit and have higher lymph node yields than those treated by a non-specialist. Post-operative mortality was lower (4.5 versus 7.0%; P = 0.032) and 5-year relative survival was higher (72.2 versus 65.6%; P = 0.012) among those treated by a specialist surgeon. In multivariate analysis, surgery by non-specialists was independently associated with increased post-operative mortality (adjusted odds ratio (OR) 1.69; P < 0.001) and poorer 5-year relative survival (adjusted relative excess risk (RER) 1.17; P = 0.045). After exclusion of post-operative deaths, there was no difference in long-term survival (adjusted RER 1.08; P = 0.505).

CONCLUSION

Five-year relative survival after elective colon cancer surgery was higher among those treated by specialist colorectal surgeons due to increased post-operative mortality among those treated by non-specialists.

LPS-induced TLR4 signaling in human colorectal cancer cells increases beta1 integrin-mediated cell adhesion and liver metastasis

Infectious complications resulting from resection of colorectal cancer (CRC) elevates the risk of cancer recurrence and metastasis, but the reason for this risk relationship is unknown. Defining the mechanisms responsible may offer opportunities to improve outcomes in a majority of patients whose tumors are resected as part of their therapy. The complex formed between Toll receptor TLR4 and myeloid differentiation factor MD2 defines a major cell surface receptor for lipopolysaccharide (LPS), a gram-negative bacterial antigen that has been implicated in infectious complications after CRC resection. As the TLR4/MD2 complex is expressed on CRC cells, we hypothesized that LPS may promote liver metastasis in CRC by stimulating TLR4 signaling. In support of this hypothesis, we report here that LPS enhances liver metastasis of human CRC cells that express TLR4/MD2 after intrasplenic graft of immunocompromised nude mice. Compared with TLR4 nonexpressing, nonmetastatic CRC cells, we observed increased in vitro adherence to different extracellular matrices and human umbilical vein endothelial cells (HUVEC). Furthermore, we observed an increased likelihood of in vivo capture within hepatic sinusoids after LPS treatment. No differences were apparent in phosphorylation of p38 and MAPK isoforms, but in metastatic CRC cells expressing surface TLR4 treatment with LPS increased Ser473 phosphorylation of AKT kinase. We showed that enhanced adherence elicited by LPS in these cells could be blocked at three different levels, using Eritoran (TLR4 small molecule antagonist), PI-103 (PI3K inhibitor), or anti-β1 integrin blocking antibodies. Taken together, the results indicate that stimulation of the TLR4/MD2 complex by LPS activates PI3K/AKT signaling and promotes downstream β1 integrin function, thereby increasing the adhesiveness and metastatic capacity of CRC cells. Our findings suggest that inhibiting LPS-induced TLR4 signaling could improve therapeutic outcomes by preventing cancer metastasis during the perioperative period of CRC resection.

The relationship between the presence and site of cancer, an inflammation-based prognostic score and biochemical parameters. Initial results of the Glasgow Inflammation Outcome Study

BACKGROUND

Cancer incidence is increasing in the United Kingdom, as well as on a global basis. Biochemical parameters, such as C-reactive protein and albumin (combined to form the modified Glasgow Prognostic Score, mGPS), alkaline phosphatase (Alk phos), gamma-glutamyl transferase (GGT) and serum calcium have been reported to be associated with cancer and non-cancer mortality. Therefore, to definitively examine the interrelationships between the above biochemical parameters, the mGPS and the presence of cancer, the Glasgow Inflammation Outcome Study was undertaken. The aim of this initial study was to examine the effect of cancer on markers of systemic inflammation induced by the liver (mGPS) and on levels of routine biochemical parameters.

METHODS

Patients (n=223 303) who had a single incidental sample taken for C-reactive protein, albumin, calcium and serum liver function tests where available, between 2000 and 2008 were studied. Those with a pathological diagnosis of cancer (n=22 715) were identified. The mGPS was constructed and liver function tests classified in accordance with the local reference ranges.

RESULTS

Patients with cancer had higher C-reactive protein and lower albumin levels (and thus a higher mGPS), higher adjusted calcium, Alk phos and GGT levels, but lower aspartate transaminase (AST) and alanine transaminase (ALT) levels (all P<0.001). The strongest associations (Spearman's correlation > or =0.3) in both the non-cancer and cancer groups were found between albumin, C-reactive protein and Alk phos, AST and ALT, AST and GGT and ALT and GGT (all P<0.001). On multivariate analysis, the associations with the presence of cancer remained with age, deprivation, C-reactive protein, albumin, adjusted calcium, Alk phos and GGT (all P<0.01). Patients following a diagnosis of cancer had lower albumin levels and thus higher mGPS (all P<0.001). Also, post-diagnosis patients were more likely to have lower adjusted calcium, bilirubin, Alk Phos, AST, ALT and GGT levels (all P<0.05). When the cancer diagnoses were ranked from those with the lowest proportion of mGPS 1 or 2 to those with the highest, the percentage of cases with a mGPS of 1 or 2 ranged from 21% in breast cancer to 46% in prostate cancer and to 68% in pulmonary cancer. Compared with breast cancer the mGPS was significantly higher in those diagnosed with dermatological, bladder, endocrinological, gynaecological, prostate, musculoskeletal, gastroesophageal, haematological, renal, colorectal, head and neck, pancreaticobiliary and pulmonary cancers (all P<0.001).

CONCLUSION

The results of the present study indicate that the systemic inflammatory response is common in a large patient cohort, increased by the presence of cancer and associated with the perturbation of a number of biochemical parameters previously reported to be associated with mortality. There is a striking parallel between the proportions of cases with a mGPS of 1 or 2 and reported survival rates in these tumours.

p53 mutation, deprivation and poor prognosis in primary breast cancer

BACKGROUND

The deprivation gap for breast cancer survival remains unexplained by stage at presentation, treatment, or co-morbidities. We hypothesised that p53 mutation might contribute to the impaired outcome observed in patients from deprived communities.

METHODS

p53 mutation status was determined using the Roche Amplichip research test in 246 women with primary breast cancer attending a single cancer centre and related to deprivation, pathology, overall, and disease-free survival.

RESULTS

p53 mutation, identified in 64/246 (26%) of cancers, was most common in 10 out of 17 (58.8%) of the lowest (10th) deprivation decile. Those patients with p53 mutation in the 10th decile had a significantly worse disease-free survival of only 20% at 5 years (Kaplan-Meier logrank chi(2)=6.050, P=0.014) and worse overall survival of 24% at 5 years (Kaplan-Meier logrank chi(2)=6.791, P=0.009) than women of deciles 1-9 with p53 mutation (c.f. 56% and 72%, respectively) or patients in the 10th decile with wild-type p53 (no disease relapse or deaths).

CONCLUSION

p53 mutation in breast cancer is associated with socio-economic deprivation and may provide a molecular basis, with therapeutic implications, for the poorer outcome in women from deprived communities.

Pronostic des cancers colorectaux et inégalités socio-économiques

It is well established that socio-economic status is a major prognostic factor for many cancers, including colorectal cancer. The aims of this review are (i) to report epidemiological data showing how socio-economic status influences colorectal cancer survival, (ii) to attempt to describe the mechanisms underlying these survival inequalities, and (iii) to assess their impact on survival of colorectal cancer.

Origins of socio-economic inequalities in cancer survival: a review

BACKGROUND

Cancer survival is known to vary by socio-economic group. A review of studies published by 1995 showed this association to be universal and resilient to the many different ways in which socio-economic status was determined. Differences were most commonly attributed to differences in stage of disease at diagnosis.

MATERIALS AND METHODS

A review of research published since 1995 examining the association of cancer survival with socio-economic variables.

RESULTS

An association between socio-economic status and cancer survival has continued to be demonstrated in the last decade of research. Stage at diagnosis and differences in treatment have been cited as the most important explanatory factors. Some research has evaluated the psychosocial elements of this association.

CONCLUSIONS

Socio-economic differences in cancer survival are now well documented. The explanatory power of stage at diagnosis, although great, should not detract from the evidence of differential treatment between social groups. Neither factor can completely explain the observed socio-economic differences in survival, however, and the importance of differences in tumour and patient factors should now be quantified.

Relationship between homocysteine and neopterin concentrations in patients with gynecological cancer

Elevated concentrations of vascular risk factor homocysteine have been described in patients with malignant diseases, and homocysteine was supposed to be useful as tumor marker. Likewise, elevated concentrations of Th1-type immune activation marker neopterin are frequently observed in patients suffering from cancer and serve as prognostic marker for the survival of patients. In this study, the relationship between homocysteine and neopterin concentrations was examined in 18 patients with gynecological cancer. Concentrations of homocysteine and cysteine were measured by HPLC in sera of patients, folic acid and vitamin B(12) levels were determined by radioimmunoassay, and neopterin concentrations were measured by ELISA. Median homocysteine concentration was 11.2 microM (interquartile range: 9.9-13.2 microM), 3 patients had levels higher than 15 microM, the upper limit of the normal range. Neopterin concentrations were increased in 13 patients (median: 11.6; 7.7-24.9 nM), cysteine (median: 234; 216-255 microM), folate (median: 7.8; 6.2-11.7 ng/ml) and vitamin B(12) (median: 352; 258-570 pg/ml) concentrations were all within reference ranges although rather at the lower side. Higher homocysteine concentrations correlated inversely with low folate concentrations (r(s)=-0.605; P<0.01) and tended to be higher in patients with higher cysteine levels (r(s)=0.457; P<0.06; ). No correlation was found between homocysteine and immune activation marker neopterin, although the three patients with elevated homocysteine concentrations tended to have higher neopterin levels as well (P<0.07). In conclusion, only a few patients with gynecological cancer present with elevated homocysteine concentrations and hyperhomocysteinemia seems only weakly related to immune activation phenomena, tumor cell proliferation probably is more important for the increase of homocysteine.

Preoperative mannan-binding lectin pathway and prognosis in colorectal cancer

PURPOSE

Deficiency of the mannan-binding lectin (MBL) pathway of innate immunity is associated with increased susceptibility to infections. In patients with colorectal cancer (CRC), postoperative infection is associated with poor prognosis. The aim of the present study was to evaluate (1) the relation between the MBL pathway and postoperative infectious complications and survival of patients resected for CRC, and (2) the role of MBL in acute phase response compared to C-reactive protein (CRP).

METHODS

Preoperative MBL concentration, MBL-associated serine protease (MBL/MASP) activity and CRP were determined in serum from 611 patients and 150 healthy controls. The patients were observed for 8 years. Postoperative infections, recurrence and survival were recorded.

RESULTS

The MBL pathway components were increased in the patients compared with the healthy controls (p < 0.0001). Low MBL levels were predictive of pneumonia (p = 0.01), and pneumonia (n = 87) was associated with poor survival (p = 0.003; HR = 1.5; 95% CI, 1.1 to 1.9). MBL and MBL/MASP activity showed no correlation with CRP (Spearman's rho = 0.02; 95% CI, -0.06 to 0.10).

CONCLUSION

Low preoperative MBL levels are predictive of pneumonia, which is associated with poorer survival. MBL concentration and MBL/MASP activity was not predictive of other postoperative infections or long-term prognosis, and showed no correlation with CRP.

The relationship between deprivation, tumour stage and the systemic inflammatory response in patients with primary operable breast cancer

The extent of deprivation (Carstairs deprivation index) was directly associated with the magnitude of the systemic inflammatory response (reduced albumin and elevated C-reactive protein, P<0.01) in patients with primary operable breast cancer (n=314). Deprivation was not associated with age, tumour size, tumour type, grade, and the proportion of patients with involved lymph nodes and oestrogen receptor status.

Influence of volume and specialization on survival following surgery for colorectal cancer

Background

Previous studies have shown that significant surgeon-related differences in survival exist following surgery for colorectal cancer. It is not clear whether these differences were due to differences in caseload or degree of specialization.

Methods

Outcome in 3200 patients who underwent resection for colorectal cancer between 1991 and 1994 was analysed on the basis of caseload and degree of specialization of individual surgeons. Five-year survival rates, and the corresponding hazard ratios adjusted for case mix, were calculated.

Results

Cancer-specific survival rate at 5 years following curative resection varied among surgeons from 53·4 to 84·6 per cent; the adjusted hazard ratios varied from 0·48 to 1·55. Cancer-specific survival rate at 5 years following curative resection was 70·2, 62·0 and 65·9 per cent for surgeons with a high, medium and low case volume respectively. There were no consistent differences in the adjusted hazard ratios by volume. Cancer-specific survival rate at 5 years following curative resection was 72·7 per cent for those treated by specialists and 63·8 per cent for those treated by non-specialists; the adjusted hazard ratio for non-specialists was 1·35 (95 per cent confidence interval 1·13 to 1·62; P = 0·001).

Conclusion

The differences in outcome following apparently curative resection for colorectal cancer among surgeons appear to reflect the degree of specialization rather than case volume. It is likely that increased specialization will lead to further improvements in survival.