Jörgen Rutegård

Defunctioning Stoma Reduces Symptomatic Anastomotic Leakage After Low Anterior Resection of the Rectum for Cancer: A Randomized Multicenter Trial

Objective:The aim of this randomized multicenter trial was to assess the rate of symptomatic anastomotic leakage in patients operated on with low anterior resection for rectal cancer and who were intraoperatively randomized to a defunctioning stoma or not. Summary Background Data:The introduction of total mesorectal excision surgery as the surgical technique of choice for carcinoma in the lower and mid rectum has led to decreased local recurrence and improved oncological results. Despite these advances, perioperative morbidity remains a major issue, and the most feared complication is symptomatic anastomotic leakage. The role of the defunctioning stoma in regard to anastomotic leakage is controversial and has not been assessed in any randomized trial of sufficient size. Methods:From December 1999 to June 2005, a total of 234 patients were randomized to a defunctioning loop stoma or no loop stoma. Loop ileostomy or loop transverse colostomy was at the choice of the surgeon. Inclusion criteria for randomization were expected survival >6 months, informed consent, anastomosis ≤7 cm above the anal verge, negative air leakage test, intact anastomotic rings, and absence of major intraoperative adverse events. Results:The overall rate of symptomatic leakage was 19.2% (45 of 234). Patients randomized to a defunctioning stoma (n = 116) had leakage in 10.3% (12 of 116) and those without stoma (n = 118) in 28.0% (33 of 118) (odds ratio = 3.4; 95% confidence interval, 1.6–6.9; P < 0.001). The need for urgent abdominal reoperation was 8.6% (10 of 116) in those randomized to stoma and 25.4% (30 of 118) in those without (P < 0.001). After a follow-up of median 42 months (range, 6–72 months), 13.8% (16 of 116) of the initially defunctioned patients still had a stoma of any kind, compared with 16.9% (20 of 118) those not defunctioned (not significant). The 30-day mortality after anterior resection was 0.4% (1 of 234) and after elective reversal a defunctioning stoma 0.9% (1 of 111). Median age was 68 years (range, 32–86 years), 45.3% (106 of 234) were females, 79.1% (185 of 234) had preoperative radiotherapy, the level of anastomosis was median 5 cm, and intraoperative blood loss 550 mL, without differences between the groups. Conclusion:Defunctioning loop stoma decreased the rate of symptomatic anastomotic leakage and is therefore recommended in low anterior resection for rectal cancer.

Risk factors for anastomotic leakage after anterior resection of the rectum.

Objective  Surgical technique and peri‐operative management of rectal carcinoma have developed substantially in the last decades. Despite this, morbidity and mortality after anterior resection of the rectum are still important problems. The aim of this study was to identify risk factors for anastomotic leakage in anterior resection and to assess the role of a temporary stoma and the need for urgent re‐operations in relation to anastomotic leakage.

The Distribution of Macrophages with a M1 or M2 Phenotype in Relation to Prognosis and the Molecular Characteristics of Colorectal Cancer

High macrophage infiltration has been correlated to improved survival in colorectal cancer (CRC). Tumor associated macrophages (TAMs) play complex roles in tumorigenesis since they are believed to hold both tumor preventing (M1 macrophages) and tumor promoting (M2 macrophages) activities. Here we have applied an immunohistochemical approach to determine the degree of infiltrating macrophages with a M1 or M2 phenotype in clinical specimens of CRC in relation to prognosis, both in CRC in general but also in subgroups of CRC defined by microsatellite instability (MSI) screening status and the CpG island methylator phenotype (CIMP). A total of 485 consecutive CRC specimens were stained for nitric oxide synthase 2 (NOS2) (also denoted iNOS) as a marker for the M1 macrophage phenotype and the scavenger receptor CD163 as a marker for the M2 macrophage phenotype. The average infiltration of NOS2 and CD163 expressing macrophages along the invasive tumor front was semi-quantitatively evaluated using a four-graded scale. Two subtypes of macrophages, displaying M1 (NOS2+) or M2 (CD163+) phenotypes, were recognized. We observed a significant correlation between the amount of NOS2+ and CD163+ cells (P<0.0001). A strong inverse correlation to tumor stage was found for both NOS2 (P<0.0001) and CD163 (P<0.0001) infiltration. Furthermore, patients harbouring tumors highly infiltrated by NOS2+ cells had a significantly better prognosis than those infiltrated by few NOS2+ cells, and this was found to be independent of MSI screening status and CIMP status. No significant difference was found on cancer-specific survival in groups of CRC with different NOS2/CD163 ratios. In conclusion, an increased infiltration of macrophages with a M1 phenotype at the tumor front is accompanied by a concomitant increase in macrophages with a M2 phenotype, and in a stage dependent manner correlated to a better prognosis in patients with CRC.

The role of the CpG island methylator phenotype in colorectal cancer prognosis depends on microsatellite instability screening status

Purpose: The aim of this study was to relate the CpG island methylator phenotype (CIMP; characterized by extensive promoter hypermethylation) to cancer-specific survival in colorectal cancer, taking into consideration relevant clinicopathologic factors, such as microsatellite instability (MSI) screening status and the BRAF V600E mutation. Experimental Design: Archival tumor samples from 190 patients from the Northern Sweden Health and Disease Study (NSHDS) and 414 patients from the Colorectal Cancer in Umeå Study (CRUMS), including 574 with cancer-specific survival data, were analyzed for an eight-gene CIMP panel using quantitative real-time PCR (MethyLight). MSI screening status was assessed by immunohistochemistry. Results: CIMP-low patients had a shorter cancer-specific survival compared with CIMP-negative patients (multivariate hazard ratio in NSHDS, 2.01; 95% confidence interval, 1.20-3.37; multivariate hazard ratio in CRUMS, 1.48; 95% confidence interval, 1.00-2.22). This result was similar in subgroups based on MSI screening status and was statistically significant in microsatellite stable (MSS) tumors in NSHDS. For CIMP-high patients, a shorter cancer-specific survival compared with CIMP-negative patients was observed in the MSS subgroup. Statistical significance was lost after adjusting for the BRAF mutation, but the main findings were generally unaffected. Conclusions: In this study, we found a poor prognosis in CIMP-low patients regardless of MSI screening status, and in CIMP-high patients with MSS. Although not consistently statistically significant, these results were consistent in two separate patient groups and emphasize the potential importance of CIMP and MSI status in colorectal cancer research. Clin Cancer Res; 16(6); 1845–55

Colorectal cancer prognosis depends on T-cell infiltration and molecular characteristics of the tumor.

The aim of this study was to relate the density of tumor infiltrating T cells to cancer-specific survival in colorectal cancer, taking into consideration the CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) screening status. The T-cell marker CD3 was stained by immunohistochemistry in 484 archival tumor tissue samples. T-cell density was semiquantitatively estimated and scored 1–4 in the tumor front and center (T cells in stroma), and intraepithelially (T cells infiltrating tumor cell nests). Total CD3 score was calculated as the sum of the three CD3 scores (range 3–12). MSI screening status was assessed by immunohistochemistry. CIMP status was determined by quantitative real-time PCR (MethyLight) using an eight-gene panel. We found that patients whose tumors were highly infiltrated by T cells (total CD3 score ≥7) had longer survival compared with patients with poorly infiltrated tumors (total CD3 score ≤4). This finding was statistically significant in multivariate analyses (multivariate hazard ratio, 0.57; 95% confidence interval, 0.31–1.00). Importantly, the finding was consistent in rectal cancer patients treated with preoperative radiotherapy. Although microsatellite unstable tumor patients are generally considered to have better prognosis, we found no difference in survival between microsatellite unstable and microsatellite stable (MSS) colorectal cancer patients with similar total CD3 scores. Patients with MSS tumors highly infiltrated by T cells had better prognosis compared with intermediately or poorly infiltrated microsatellite unstable tumors (log rank P=0.013). Regarding CIMP status, CIMP-low was associated with particularly poor prognosis in patients with poorly infiltrated tumors (multivariate hazard ratio for CIMP-low versus CIMP-negative, 3.07; 95% confidence interval, 1.53–6.15). However, some subset analyses suffered from low power and are in need of confirmation by independent studies. In conclusion, patients whose tumors are highly infiltrated by T cells have a beneficial prognosis, regardless of MSI, whereas the role of CIMP status in this context is less clear.

What Is the Risk for a Permanent Stoma After Low Anterior Resection of the Rectum for Cancer? A Six-Year Follow-Up of a Multicenter Trial

PURPOSE: The aim of this study was to assess the risk for permanent stoma after low anterior resection of the rectum for cancer. METHODS: In a nationwide multicenter trial 234 patients undergoing low anterior resection of the rectum were randomly assigned to a group with defunctioning stomas (n = 116) or a group with no defunctioning stomas (n = 118). The median age was 68 years, 45% of the patients were women, 79% had preoperative radiotherapy, and 4% had International Union Against Cancer cancer stage IV. The patients were analyzed with regard to the presence of a permanent stoma, the type of stoma, the time point at which the stoma was constructed or considered as permanent, and the reasons for obtaining a permanent stoma. Median follow-up was 72 months (42-108). One patient with a defunctioning stoma who died within 30 days after the rectal resection was excluded from the analysis. RESULTS: During the study period 19% (45/233) of the patients obtained a permanent stoma: 25 received an end sigmoid stoma and 20 received a loop ileostomy. The end sigmoid stomas were constructed at a median of 22 months (1-71) after the low anterior resection of the rectum, and the loop ileostomies were considered as permanent at a median of 12.5 months (1-47) after the initial rectal resection. The reasons for loop ileostomy were metastatic disease (n = 6), unsatisfactory anorectal function (n = 6), deteriorated general medical condition (n = 3), new noncolorectal cancer (n = 2), patient refusal of further surgery (n = 2), and chronic constipation (n = 1). Reasons for end sigmoid stoma were unsatisfactory anorectal function (n = 22) and urgent surgery owing to anastomotic leakage (n = 3). The risk for permanent stomas in patients with symptomatic anastomotic leakage was 56% (25/45) compared with 11% (20/188) in those without symptomatic anastomotic leakage (P < .001). CONCLUSION: One patient of 5 ended up with a permanent stoma after low anterior resection of the rectum for cancer, and half of the patients with a permanent stoma had previous symptomatic anastomotic leakage.

The prognostic role of KRAS, BRAF, PIK3CA and PTEN in colorectal cancer

BackgroundMutations in KRAS, BRAF, PIK3CA and PTEN expression have been in focus to predict the effect of epidermal growth factor receptor-blocking therapy in colorectal cancer (CRC). Here, information on these four aberrations was collected and combined to a Quadruple index and used to evaluate the prognostic role of these factors in CRC.PatientsWe analysed the mutation status in KRAS, BRAF and PIK3CA and PTEN expression in two separate CRC cohorts, Northern Sweden Health Disease Study (NSHDS; n=197) and Colorectal Cancer in Umeå Study (CRUMS; n=414). A Quadruple index was created, where Quadruple index positivity specifies cases with any aberration in KRAS, BRAF, PIK3CA or PTEN expression.ResultsQuadruple index positive tumours had a worse prognosis, significant in the NSHDS but not in the CRUMS cohort (NSHDS; P=0.003 and CRUMS; P=0.230) in univariate analyses but significance was lost in multivariate analyses. When analysing each gene separately, only BRAF was of prognostic significance in the NSHDS cohort (multivariate HR 2.00, 95% CI: 1.16–3.43) and KRAS was of prognostic significance in the CRUMS cohort (multivariate HR 1.48, 95% CI: 1.02–2.16). Aberrations in PIK3CA and PTEN did not add significant prognostic information.ConclusionsOur results suggest that establishment of molecular subgroups based on KRAS and BRAF mutation status is important and should be considered in future prognostic studies in CRC.

Human Colorectal Cancers with an Intact p16/Cyclin D1/pRb Pathway Have Up-Regulated p16 Expression and Decreased Proliferation in Small Invasive Tumor Clusters

A systematic spatial heterogeneity with high proliferative activity at the luminal border and low activity at the invasive margin is an unexpected behavior that has been observed in colorectal cancer (CRC). To clarify this phenomenon and possible underlying regulatory mechanisms, we have by immunohistochemistry elucidated the proliferative activity and the expression of G1/S regulatory proteins in small and large tumor cell clusters at the invasive margin in 97 CRCs. By identifying small tumor clusters at the tumor front, actually invading cancer cells could be characterized and analyzed separately. These cells could then be compared with the main tumor mass represented by the larger tumor clusters. The proliferation was significantly lower in small tumor clusters compared with larger clusters (P < 0.001) and the decrease in proliferation was correlated with a p16 up-regulation (r(s) = -0.41, P < 0.001). Interestingly, CRCs lacking p16 expression (18%) or tumors with other aberrations in the p16/cyclin D1/pRb pathway had a less pronounced decrease in proliferation between large and small clusters (P < 0.001), further strengthening the association between p16 and ceased proliferation at the invasive margin. This contrasts to tumors with low p27 or abnormal p53 levels showing sustained proliferation in small tumor clusters. Our findings imply that invading CRC cells generally have low proliferative activity, and this phenomenon seems to be mediated through p16 and the p16/cyclin D1/pRb pathway.

Low tumour cell proliferation at the invasive margin is associated with a poor prognosis in Dukes' stage B colorectal cancers

SummaryThe conflicting results about the prognostic impact of tumour cell proliferation in colorectal cancer might be explained by the heterogeneity observed within these tumours. We have investigated whether a systematic spatial heterogeneity exists between different compartments, and whether the presence of such a systematic heterogeneity has any impact on survival. Fifty-six Dukes’ stage B colorectal cancers were carefully morphometrically quantified with respect to the immunohistochemical expression of the proliferative marker Ki-67 at both the luminal border and the invasive margin. The proliferative activity was significantly higher at the luminal border compared with the invasive margin (P < 0.001), although the two compartments were also significantly correlated with each other. Tumours with low proliferation at the invasive margin had a significantly poorer prognosis both in univariate (P = 0.014) and in multivariate survival analyses (P = 0.042). We conclude that Dukes’ B colorectal cancers exhibit a systematic spatial heterogeneity with respect to proliferation, and tumours with low proliferation at the invasive margin had a poor prognosis. The present data independently confirm recent results from the authors, and provide new insights into the understanding of tumour cell proliferation in colorectal cancer.

Colorectal cancer cells activate adjacent fibroblasts resulting in FGF1/FGFR3 signaling and increased invasion.

Cancer-associated fibroblasts expressing fibroblast activation protein (FAP) have been implicated in the invasive behavior of colorectal cancer. In this study, we use FAP expression as a marker of fibroblast activation and analyze the effect of activated fibroblasts on colorectal cancer migration and invasion in experimental cell studies. We also investigated the expression pattern of FAP in cancer-associated fibroblasts during transformation from benign to malignant colorectal tumors. In immunohistochemical analyses, FAP was expressed in fibroblasts in all colorectal cancer samples examined, whereas all normal colon, hyperplastic polyps, or adenoma samples were negative. In in vitro studies, conditioned medium from colon cancer cells, but not adenoma cells, activated fibroblasts by inducing FAP expression. These activated fibroblasts increased the migration and invasion of colon cancer cells in Boyden chamber experiments and in a three-dimensional cell culture model. We identify fibroblast growth factor 1/fibroblast growth factor receptor 3 (FGF1/FGFR-3) signaling as mediators leading to the increased migration and invasion. Activated fibroblasts increase their expression of FGF1, and by adding a fibroblast growth factor receptor inhibitor, as well as an FGF1-neutralizing antibody, we reduced the migration of colon cancer cells. Our findings provide evidence of a possible molecular mechanism involved in the cross talk between cancer cells and fibroblasts leading to cancer cell invasion.