Cancer invasion to Auerbach's plexus is an important prognostic factor in patients with pT3-pT4 colorectal cancer

Tumor-associated microbiota in colorectal cancer with vascular tumor thrombus and neural invasion and association with clinical prognosis

Neural invasion (NI) and vascular tumor thrombus (VT) are associated with poor prognosis in patients with colorectal cancer (CRC). In this study, we apply 16S rRNA amplicon sequencing to tumor tissues and adjacent normal tissues in patients with CRC to determine the microbial differences. A discovery cohort, including 30 patients with NI, 23 with VT, and 35 with double-negative CRC tissue, is utilized. Then, we analyze the relationship between the specific bacterial taxa and indicators of different dimensions in separate cohorts. In the discovery cohort, the diversity and composition of the gut microbiome distinctly differ between the tumor and nontumor tissues in the NI and VT groups. A high abundance of Cupriavidus is found to be related to a short survival time of NI CRC, while Herbaspirillum is a potential microbial biomarker predicting the prognosis of patients with CRC with NI or VT. Moreover, the abundance of Cupriavidus or Herbaspirillum is associated with some clinical patient characteristics and prognosis, respectively. In conclusion, this study is the first to comprehensively elaborate the differences in the gut microbiota of patients with CRC with different invasion statuses and to prove the relationship between some gut microbiota and clinical patient characteristics.

Lymphovascular invasion represents a superior prognostic and predictive pathological factor of the duration of adjuvant chemotherapy for stage III colon cancer patients

BACKGROUND

Lymphovascular invasion (LVI) and perineural invasion (PNI) can indicate poor survival outcomes in colorectal cancer, but few studies have focused on stage III colon cancer. The current study aimed to confirm the prognostic value of LVI and PNI and identify patients who could benefit from a complete duration of adjuvant chemotherapy based on the two pathological factors.

METHODS

We enrolled 402 consecutive patients with stage III colon cancer who received colon tumor resection from November 2007 to June 2016 at Sun Yat-sen University Cancer Center. Survival analyses were performed by using Kaplan-Meier method with log-rank tests. Risk factors related to disease-free survival (DFS) and overall survival (OS) were identified through Cox proportional hazards analysis.

RESULTS

141 (35.1%) patients presented with LVI, and 108 (26.9%) patients with PNI. The LVI-positive group was associated with poorer 3-year DFS (86.5% vs. 76.3%, P = 0.001) and OS (96.0% vs. 89.1%, P = 0.003) rates compared with the LVI-negative group. The PNI-positive group showed a worse outcome compared with the PNI-negative group in 3-year DFS rate (72.5% vs. 86.7%, P < 0.001). Moreover, LVI-positive group present better 3-year DFS and OS rate in patients completing 6-8 cycles of adjuvant chemotherapy than those less than 6 cycles (3-year DFS: 80.0% vs. 64.9%, P = 0.019; 3-year OS: 93.2% vs. 76.3%, P = 0.002).

CONCLUSIONS

LVI is a superior prognostic factor to PNI in stage III colon cancer patients undergoing curative treatment. PNI status can noly predict the 3-year DFS wihout affecting the 3-year OS. Furthermore, LVI also represents an effective indicator for adjuvant chemotherapy duration.

Three-dimensional imaging of intramural perineural invasion in colorectal cancer: Three-dimensional reconstruction approach with multiple immunohistochemically stained sections

Perineural invasion (PNI) at Auerbach's plexus in colorectal cancer (CRC), known as intramural PNI, is associated with adverse prognostic outcomes. This study aimed to characterize the three-dimensional (3D) architecture of CRC with intramural PNI and to evaluate the morphological features of tumor invasion around nerve tissue. Serial tissue sections from two cases of CRC were stained with cytokeratin AE1/AE3 and an anti-S-100 protein antibody. 3D models were reconstructed by scanning the virtual slides. In one case, intramural PNI was observed at the horizontal invasive front. The 3D reconstruction model showed tumor cells that appeared to infiltrate along the nervous meshwork, the structure of which was preserved. In the other case, intramural PNI was observed both at and behind the horizontal invasive front, and the 3D reconstruction model showed that the tumor cells appeared to be involved with nerve cells at the focal part of the horizontal invasive front. However, the nervous meshwork structure was not well identified in cancer-involved areas. This is the first study to characterize the 3D structure of tumor invasion around nerve tissue in CRC, demonstrating the morphological features of intramural PNI in CRC.

S100-stained perineural invasion is associated with worse prognosis in stage I/II colorectal cancer: Its possible association with immunosuppression in the tumor

Perineural invasion (PNI) is known as a poor prognostic factor in colorectal cancer (CRC). Although histopathological evaluation of PNI is usually conducted on hematoxylin and eosin (HE)-stained sections (HE-PNI), it remains controversial whether PNI can be precisely evaluated only by HE-staining, and its concise mechanisms causing worse prognosis remains elusive. In this study, we examined the impact of PNI evaluated by S-100-immunostaining (S100-PNI) on postoperative mortality in 279 consecutive CRC patients and further investigated its association with the tumor immune microenvironment. S100-PNI was present in 67.3% of tumors whereas HE-PNI was present in 18.5%. A 5-year cumulative incidence of death in the S100-PNI-positive group was significantly higher than that in the S100-PNI-negative group. Further statistical analyses revealed that S100-PNI was an independent prognostic factor of all-cause mortality in stage I/II but not in stage III/IV. Importantly, S100-PNI was associated with the altered tumor immune microenvironment. Infiltrating immune cell profiling revealed that stromal lymphocytic reaction, which was inversely correlated with postoperative mortality, was significantly reduced in S100-PNI-positive tumors compared to S100-PNI-negative tumors in stage I/II. These results indicated that S100-PNI was a poor prognostic factor in stage I/II CRC with possible association with immunosuppression in the tumor.

Pathology and Prognosis of Colonic Adenocarcinomas With Intermediate Primary Tumor Stage Between pT2 and pT3

CONTEXT.—

Primary tumor stage (pT) is an important prognostic indicator in colonic adenocarcinomas; however, cases that have no muscle fibers beyond the advancing tumor edge but also show no extension beyond the apparent outer border of muscularis propria (termed pT2int), have not been previously studied.

OBJECTIVE.—

To address the clinicopathologic characteristics and prognosis of pT2int tumors.

DESIGN.—

We recharacterized 168 colon carcinomas and compared pT2int cases to bona fide pT2 and pT3 tumors.

RESULTS.—

In side-by-side analysis, 21 pT2int cases diverged from 29 pT2 tumors only in terms of larger size (P = .03), but they were less likely to show high-grade (P = .03), lymphovascular (P < .001), and extramural venous invasion (P = .04); discontinuous tumor deposits (P = .02); lymph node involvement (P = .001); and advanced stage (P = .001), compared with 118 pT3 tumors. Combining pT2int with pT2 cases (versus pT3) was a better independent predictor of negative lymph nodes in multivariate analysis (P = .04; odds ratio [OR], 3.96; CI, 1.09-14.42) and absent distant metastasis in univariate analysis (P = .04), compared with sorting pT2int with pT3 cases (versus pT2). Proportional hazards regression showed that pT2 and pT2int cases together were associated with better disease-free survival compared with pT3 tumors (P = .04; OR, 3.65; CI, 1.05-12.70). Kaplan-Meier analysis demonstrated that when pT2int were grouped with pT2 tumors, they were significantly less likely to show disease progression compared with pT3 (P = .002; log-rank test) and showed a trend toward better disease-specific survival (P = .06), during a mean patient follow-up of 44.9 months.

CONCLUSIONS.—

These data support the conclusion that pT2int carcinomas have clinicopathologic characteristics and are associated with patient outcomes more closely aligned with pT2 rather than pT3 tumors.

Perineural Invasion Is a Strong Prognostic Factor but Not a Predictive Factor of Response to Adjuvant Chemotherapy in Node-Negative Colon Cancer

Purpose

To validate the prognostic value and evaluate the predictive value of response to adjuvant chemotherapy of perineural invasion (PNI) in node-negative colon cancer using the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) 18 tumor registry database.

Methods

Patients diagnosed with colon cancer from the SEER database between January 1, 2010 and December 31, 2015 were identified. Chi-square analysis was performed to evaluate different demographic and clinical features of patients between PNI-negative (PNI (-)) and PNI-positive (PNI (+)) groups. Univariate and multivariate Cox proportional hazard regression models were built to examine the relationship of demographic and clinical features and survival outcomes with the hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

In total, 57,255 node-negative colon cancer patients were extracted from the SEER database. The receipt of chemotherapy was not an independent prognostic factor for CSS in T3 colon cancer with or without the presence of PNI (P >0.05). The receipt of chemotherapy was independently associated with 34.0% decreased risk of cancer-specific mortality compared with those without the receipt of chemotherapy in T4 colon cancer without the presence of PNI (HR = 0.660, 95%CI = 0.559-0.779, P <0.001); the receipt of chemotherapy was independently associated with 36.0% decreased risk of cancer-specific mortality compared with those without the receipt of chemotherapy in T4 colon cancer with the presence of PNI (HR = 0.640, 95%CI = 0.438-0.935, P = 0.021).

Conclusions

The present study demonstrated the poor prognosis of PNI (+) in both stage I and II colon cancer. However, the presence of PNI was not a predictive factor of response to adjuvant chemotherapy in node-negative colon cancer.

Patient Selection for Adjuvant Chemotherapy in High-Risk Stage II Colon Cancer: A Systematic Review and Meta-Analysis

OBJECTIVES

Patients with high-risk stage II colon cancer (CC) are recommended to undergo adjuvant chemotherapy (ACT). However, whether such patients can benefit from ACT remains unclear. This meta-analysis aimed to investigate the clinicopathologic parameters that are important for selecting patients for ACT in high-risk stage II CC.

METHODS

We systematically retrieved articles from PubMed, the Cochrane Library, and Embase that were published up to September 13, 2018. We analyzed overall survival (OS) and disease-free survival (DFS) based on hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

A total of 23 cohort studies and 1 randomized controlled trial were included in our study. Overall analyses showed that ACT improved OS (HR=0.64, 95% CI=0.51-0.80, P<0.001) and DFS (HR=0.46, 95% CI=0.28-0.76, P=0.002) in patients with high-risk stage II CC. Subgroup analyses showed that ACT improved OS in patients with localized intestinal perforation and obstruction and pT4 lesions and improved OS and DFS in patients with <12 sampled lymph nodes. However, ACT had no significant effect on OS in patients with lymphovascular invasion, perineural invasion, or poorly differentiated histology.

CONCLUSIONS

Our study suggests that not all high-risk factors (lymphovascular invasion, perineural invasion, poorly differentiated histology) show a benefit from ACT. Randomized controlled trials selectively targeting high-risk patients will need to be conducted in the future.

Clinical implications of perineural invasion in patients with colorectal cancer

Perineural invasion (PNI) is a prominent characteristic of multiple solid tumors and indicates poor prognosis. Previous data concerning the impact of PNI on prognosis of patients with colorectal cancer (CRC) are conflicting, and little is known about risk factors of PNI. The aim of our study was to reveal the clinical implication of PNI on survival outcome and identify risk factors for the poor prognosis in patients with CRC.We retrospectively reviewed 627 patients who were diagnosed with CRC and underwent curative surgical resection. The differences in several clinicopathologic characteristics were compared between PNI positive and PNI negative groups. Multivariate logistic regression analysis was performed to identify predictors of CRC with PNI. Five-year overall survival (OS) and disease-free survival (DFS) were calculated using the Kaplan-Meier method, and the difference in survival rate was assessed by the log-rank test. The variables that had prognostic potential, as indicated by univariate analyses, were subjected to multivariate analyses with the Cox proportional hazards regression model.PNIs were identified in 79 patients (12.6%). Age, T classification, N classification, M classification, UICC classification, and lymphovascular invasion were significantly associated with PNI. Multivariate logistic regression analysis demonstrated that only lymphovascular invasion was a predictor of PNI. Pathologic evidence of PNI was not associated with survival outcome (the 5-year OS [P = .560] and DFS [P = .083]). Cox proportional hazards regression model revealed that age and N2/3 classification were independent prognostic factors for poorer OS and DFS. M1 stage (95% confidence interval [CI] = 0.228-0.585, P = .000), III/IV stage (95% CI = 0.335-0.920, P = .022), and number of sampled lymph nodes (95% CI = 0.951-0.987, P = .001) were independently prognostic for poorer OS, while history of other malignancy (95% CI = 1.133-2.813, P = .012) was identified as an independent prognostic factor for poorer DFS.Our study indicates that PNI is not an independent poor prognostic factor in patients with CRC and those patients with PNI may not benefit from postoperative adjuvant chemotherapy.

Accelerated perineural invasion in colitis-associated cancer: A retrospective cohort study

Perineural invasion (PNI) is a prognostic factor in patients with colorectal cancer. Neurotrophic factors, molecular determinants of PNI, are altered in their expression levels in patients with ulcerative colitis. In this study, we evaluated the frequency of PNI in colitis-associated cancer (CAC) and sporadic cancer.We retrospectively reviewed 778 colorectal cancers with pathological T3-T4 in 761 patients all of whom were surgically resected without preoperative treatment. The lesions were classified into either CAC or sporadic cancer based on the clinical information. Clinicopathological findings including PNI were compared between CACs and sporadic cancers. Moreover, we analyzed the risk factors for positive PNI by multivariate analysis using a logistic regression model.Ten of the cancers (1.3%) were diagnosed as CACs, and the remaining 768 as sporadic cancers. CACs were characterized by being nonobstructive and predominantly located in the rectum. The CACs had a larger size and more frequent undifferentiated histology than sporadic cancers. PNI was observed more frequently in CACs (90%) than in sporadic cancers without obstruction (45%, P = .007). On multivariate analysis, CAC was one of the significant factors associated with PNI (odds ratio: 9.05, P = .040).Our results suggest that CAC was more likely to exhibit PNI than sporadic colorectal cancer.

Obstruction is associated with perineural invasion in T3/T4 colon cancer

AIM

Perineural invasion (PNI) is a risk factor for recurrence and metastasis and consequently leads to decreased survival in patients with various malignancies. Recent studies showed that stent placement in obstructive colon cancer increases the frequency of PNI. We hypothesized that mechanical stress including obstruction itself may be associated with PNI.

METHOD

We retrospectively reviewed 496 patients with pathological T3 or T4 colon cancer who did not receive preoperative treatment. Data were collected from medical charts and pathological findings. The relationships between PNI and other clinicopathological factors were analysed using univariate and multivariate analyses.

RESULTS

PNI was observed in 239 (48%) patients. Obstruction was markedly more frequent in PNI-positive cancer (39%) than in PNI-negative cancer (24%, P = 0.0003). Multivariate analyses identified obstruction as one of the significant factors associated with PNI (OR 1.68, P = 0.028). Moreover, in 414 patients without distant metastasis who underwent complete resection, PNI was an independent factor associated with poor recurrence-free survival (hazard ratio 2.35, P = 0.003). The coexistence of PNI and obstruction resulted in greater decreases in recurrence-free survival than PNI-negative and/or non-obstructive cases.

CONCLUSION

Our results suggest that obstruction is associated with PNI and consequently contributes to an increased postoperative recurrence in colon cancer.

Lymphovascular Invasion and Perineural Invasion Negatively Impact Overall Survival for Stage II Adenocarcinoma of the Colon

BACKGROUND

Lymphovascular invasion and perineural invasion are histopathological features associated with higher-risk colon cancer.

OBJECTIVE

The purpose of this study was to quantify the impact of lymphovascular and perineural invasion on overall survival after diagnosis and to determine the protective effect of adjuvant chemotherapy for early adenocarcinoma with high-risk factors.

DESIGN

This was a retrospective database review of the 2010-2014 National Cancer Database for colon cancer.

SETTINGS

Individuals diagnosed with invasive adenocarcinoma of the colon (histology code 8140) with primary surgical resection with >12 nodes harvested and no positive nodes on pathological examination were included.

PATIENTS

A total of 32,493 patients underwent surgical resection for stage II adenocarcinoma of the colon.

INTERVENTIONS

The study involved multivariate Cox regression analysis of the impact of lymphovascular and perineural invasion and adjuvant chemotherapy on overall survival after a diagnosis of stage II adenocarcinoma of the colon.

MAIN OUTCOME MEASURES

Survival after a diagnosis of stage II adenocarcinoma of the colon was measured.

RESULTS

Five-year survival after diagnosis and surgical resection without adjuvant chemotherapy was lower for patients with lymphovascular (60.0%), perineural (56.9%), and lymphovascular and perineural invasion (55.8%) compared with double-negative disease (66.1%). Log-rank testing confirmed that adjuvant chemotherapy improved 5-year survival after diagnosis for lymphovascular (85.5%), perineural (83.6%), and lymphovascular and perineural invasion (74.3%). After controlling for differences in cohorts, Cox regression analysis showed an increased HR for mortality of 14.0% for lymphovascular (HR = 1.141 (95% CI, 1.060-1.228)), 32.1% for perineural (HR = 1.321 (95% CI, 1.176-1.483)), and 41.0% for lymphovascular and perineural invasion (HR = 1.409 (95% CI, 1.231-1.612)) compared with having neither. Chemotherapy showed a 43% reduction in hazard for mortality (HR = 0.570 (95% CI, 0.513-0.633)).

LIMITATIONS

The study was limited by its retrospective review and observational bias.

CONCLUSIONS

Lymphovascular and perineural invasion have a detrimental effect on survival after diagnosis of stage II adenocarcinoma of the colon. Chemotherapy may be protective specifically when lymphovascular and perineural invasion are present. See Video Abstract at http://links.lww.com/DCR/A786.

A novel histologic grading system based on lymphovascular invasion, perineural invasion, and tumor budding in colorectal cancer

PURPOSE

This study aimed to evaluate the prognostic significance of lymphovascular (LVI), perineural invasion (PNI), and tumor budding positivity in patients with colorectal cancer.

METHODS

From January 2008 to December 2011, 3707 consecutive patients who underwent curative surgery for stage I-III colorectal cancer were assessed. These patients were then categorized into four groups based on LVI, PNI, and tumor budding (risk grouping): all negative (n = 1495), 1 + only (n = 1063), 2 + only (n = 861), and all positive (n = 288).

RESULTS

With a median follow-up period of 52 months, the 5-year disease-free survival rates of the risk groups were significantly different in terms of cancer staging (stage I, Stage II, and Stage III: P = 0.006, P < 0.001, and P < 0.001, respectively). In the multivariate analysis, risk grouping was an independent prognostic factor of disease-free survival. Preoperative carcinoembryonic antigen level, tumor size, T category, and N category were independent predictors of LVI, PNI, and tumor budding positivity.

CONCLUSION

Risk grouping based on LVI, PNI, and tumor budding positivity is a strong predictor of disease-free survival in patients with colorectal cancer.

Fibrosis in metastatic lymph nodes is clinically correlated to poor prognosis in colorectal cancer

Background

Tumor microenvironment including fibrosis has a pivotal role in cancer growth and distant metastasis. Fibrosis is a known risk factor for carcinogenesis, but its biological role in disease invasion and metastasis in colorectal cancer (CRC) remains unclear. In particular, there is no report on how fibrosis of metastatic lymph nodes (MLNs) in CRC contributes to prognosis.

Methods

We reviewed 94 colorectal adenocarcinoma patients with MLNs who underwent colectomy. Both the primary tumors and MLNs were analyzed for alpha-smooth muscle actin (α-SMA) expression and collagen deposition.

Results

Higher α-SMA expression and collagen deposition in MLNs were associated with significantly shorter relapse-free survival and overall survival in CRC patients. α-SMA expression in MLNs (HR, 1.53; p = 0.034) was independent predictive factor of overall survival in multivariate Cox proportional hazards regression analysis of clinicopathological factors. In the Stage III patient subgroup, α-SMA expression in MLNs was a strong prognostic marker (HR, 3.01; p = 0.006). On the other hand, higher α-SMA expression and collagen deposition in primary tumors were associated with short overall survival, but they were not significant factors in multivariate Cox regression analyses. In MLNs, the podoplanin signals co-localized with α-SMA expression and were confirmed by the dual immunofluorescence staining, implying that the MLN stromal cells were fibroblastic reticular cells.

Conclusion

Both high collagen deposition and high α-SMA expression in MLNs predicted poor prognosis in CRC.

Colorectal Cancer Cells Adhere to and Migrate Along the Neurons of the Enteric Nervous System

BACKGROUND & AIMS

In several types of cancers, tumor cells invade adjacent tissues by migrating along the resident nerves of the tumor microenvironment. This process, called perineural invasion, typically occurs along extrinsic nerves, with Schwann cells providing physical guidance for the tumor cells. However, in the colorectal cancer microenvironment, the most abundant nervous structures belong to the nonmyelinated intrinsic enteric nervous system (ENS). In this study, we investigated whether colon cancer cells interact with the ENS.

METHODS

Tumor epithelial cells (TECs) from human primary colon adenocarcinomas and cell lines were cocultured with primary cultures of ENS and cultures of human ENS plexus explants. By combining confocal and atomic force microscopy, as well as video microscopy, we assessed tumor cell adhesion and migration on the ENS. We identified the adhesion proteins involved using a proteomics approach based on biotin/streptavidin interaction, and their implication was confirmed further using selective blocking antibodies.

RESULTS

TEC adhered preferentially and with stronger adhesion forces to enteric nervous structures than to mesenchymal cells. TEC adhesion to ENS involved direct interactions with enteric neurons. Enteric neuron removal from ENS cultures led to a significant decrease in tumor cell adhesion. TECs migrated significantly longer and further when adherent on ENS compared with on mesenchymal cells, and their trajectory faithfully followed ENS structures. Blocking N-cadherin and L1CAM decreased TEC migration along ENS structures.

CONCLUSIONS

Our data show that the enteric neuronal network guides tumor cell migration, partly via L1CAM and N-cadherin. These results open a new avenue of research on the underlying mechanisms and consequences of perineural invasion in colorectal cancer.

Impact of perineural invasion on survival in node negative colon cancer

Perineural invasion (PNI) has been implicated as a poor prognostic indicator in many cancers. The National Comprehensive Cancer Network recommends consideration of observation or adjuvant therapy in the presence of PNI in early colon cancer. These recommendations are based on single institutional studies that fail to evaluate PNI within the context of adjuvant chemotherapy. The US National Cancer Database (2004-2012) was reviewed for patients with node negative colon cancer, and stratified by PNI and receipt of chemotherapy. Of 21,488 patients evaluated, 55.2% had T3 disease (n = 11,852), 23.1% had T2 (n = 4,971), 14.4% had T1 (n = 3,088), and 7.3% had T4 disease (n = 1,577); 4.6% (n = 987) had PNI. Most patients (86.8%, n = 18,641) did not have PNI and did not receive chemotherapy; 8.7% (n = 1,860) did not have PNI but received chemotherapy; 3.7% (n = 785) had PNI and did not receive chemotherapy, and 0.9% (n = 202) had PNI and received chemotherapy. Among those with PNI, patients who received chemotherapy tended to be younger (P<0.001), covered by private insurance (P<0.001), with fewer comorbidities (P<0.001), and greater T stage disease (P<0.001). Those with PNI who received chemotherapy had significantly improved survival over those who did not in T3-4 disease (P<0.001), but not in T1-2 disease. On multivariate analysis, those with PNI had a 38% greater hazard of mortality (HR 1.38, P<0.001). Additionally, chemotherapy decreased the hazard of mortality by 43% (HR 0.57, P<0.001). PNI appears to be an independent poor prognostic indicator in stage T3-4 node negative colon cancer. Chemotherapy administered to this patient population is associated with improved survival.

Extramural perineural invasion in pT3 and pT4 rectal adenocarcinoma as prognostic factor after preoperative chemoradiotherapy

Perineural invasion (PNI) is widely studied in malignant tumors, and its prognostic significance is well demonstrated in the head and neck and prostate carcinomas, but its significance in rectal cancer is controversial. Most studies have focused on evaluating mural PNI (mPNI); however, extramural PNI (ePNI) may influence the prognosis after rectal cancer resection. We evaluated the prognostic value of ePNI compared with mPNI and with non-PNI, in rectal resections after preoperative chemoradiotherapy in 148 patients with pT3 and pT4 rectal carcinomas. PNI was identified in 35 patients (23.6%), 60% of which were in the mPNI group. Factors associated with PNI were tumor invasion depth, lymph node metastasis, lymphovascular invasion, and venous invasion; patients with PNI were more likely to have positive resection margins (65.7% versus 11.6%). ePNI, compared with mPNI, was associated with female sex (64.3% versus 28.6%), positive surgical margins (42.8% versus 28.6%), recurrence (50% versus 28.6%), and death (92.9% versus 28.6%). The 5-year disease-specific survival rate was 78.1% for patients without PNI, compared with 63.7% for the mPNI group and 26.4% for the ePNI group (P<.001). On multivariate analysis, the independent adverse prognostic factors were ePNI (odds ratio [OR], 22.17; 95% confidence interval [CI], 17.03-24.58; P<.001), overall recurrence (OR, 9.19; CI, 6.11-10.63; P=.002), clinical stage IV (OR, 8.56; CI, 6.34-9.47; P=.003), and positive surgical margin (OR, 3.95; CI, 2.00-4.28; P=.047). In conclusion, we demonstrated the prognostic effect of ePNI for disease-specific survival in surgically resected pT3-pT4 rectal cancer patients with preoperative chemoradiotherapy.

Influence of perineural invasion in predicting overall survival and disease-free survival in patients With locally advanced gastric cancer

BACKGROUND

The aim of the present study was to evaluate the prognostic significance of perineural invasion (PNI) in locally advanced gastric cancer patients who underwent D2 gastrectomy and adjuvant chemotherapy.

METHODS

The records of a series of 103 patients undergoing D2 gastrectomy with curative intent combined with adjuvant chemotherapy from January 2004 to December 2014 were retrospectively reviewed.

RESULTS

PNI was positive in 47 (45.6%) specimens. The 1-, 3-, and 5-year overall survival rates were 81%, 55%, and 42%, respectively. The 1-, 3-, and 5-year disease-free survival (DFS) rates were 76%, 57%, and 49%, respectively. A multivariate analysis showed that age number of positive lymph nodes, T stage, and PNI were independently associated with overall survival. Regarding DFS, the multivariate analysis showed that only PNI was independently associated with DFS.

CONCLUSIONS

PNI and T stage and positive lymph nodes are independent markers of poor prognosis in patients with gastric cancer. PNI should be incorporated in the postoperative staging system for planning follow-up after surgery and in our opinion to propose more aggressive postoperative therapies in PNI-positive patients.

Perineural Invasion is a Strong Prognostic Factor in Colorectal Cancer: A Systematic Review

Perineural invasion (PNI) is a possible route for metastatic spread in various cancer types, including colorectal cancer (CRC). PNI is linked to poor prognosis, but systematic analyses are lacking. This study systematically reviews the frequency and impact of PNI in CRC. A literature search was performed using PubMed database from inception to January 1, 2014. Data were analyzed using Review Manager 5.3. A quality assessment was performed on the basis of modified REMARK criteria. Endpoints were local recurrence (LR), 5-year disease-free survival (5yDFS), 5-year cancer-specific survival (5yCSS), and 5-year overall survival (5yOS). Meta-analysis was performed in terms of risk ratios (RR) and hazard ratios (HR) with 95% confidence interval (95% CI). In this meta-analysis, 58 articles with 22,900 patients were included. PNI was present in 18.2% of tumors. PNI is correlated with increased LR (RR 3.22, 95% CI, 2.33-4.44) and decreased 5yDFS (RR 2.35, 95% CI, 1.66-3.31), 5yCSS (RR 3.61, 95% CI, 2.76-4.72), and 5yOS (RR 2.09, 95% CI, 1.68-2.61). In multivariate analysis PNI remains an independent prognostic factor for 5yDFS, 5yCSS, and 5yOS (HR 2.35, 95% CI, 1.97-3.08; HR 1.91, 95% CI, 1.50-2.42; and HR 1.85, 95% CI, 1.63-2.12, respectively). We confirmed the strong impact of PNI for LR and survival in CRC. The prognostic value of PNI is similar to that of well-established prognostic factors as depth of invasion, differentiation grade, lymph node metastases, and lymphatic and extramural vascular invasion. Therefore, PNI should be one of the factors in the standardized reporting of CRC and might be considered a high-risk feature.

Outcomes of ultra-low anterior resection combined with or without intersphincteric resection in lower rectal cancer patients

PURPOSE

We evaluated the current practice of ultra-low anterior resection (uLAR) in patients with lower rectal cancer and compared uLARs using mostly transabdominal approach with or without intersphincteric resection (ISR).

METHODS

A total of 624 consecutive lower rectal cancer patients undergoing curative uLAR were prospectively enrolled as ISR+ vs. ISR- groups (329 vs. 295 patients) between 2005 and 2012. The ISR+ group additionally received levator-sphincter reinforcement after distal resection.

RESULTS

The circumferential resection margin (CRM) + rate (≤1 mm) was 2.1 % in the two groups. Postoperative ileus occurred more in the ISR- group than in the ISR+ group (p = 0.02). Substantial erectile dysfunction occurred 1.8 times more frequently in the ISR- group than in the ISR+ group (32 vs. 18.1 %; p = 0.01) among male patients at 2 years postoperatively. The urge to defecate volume and maximal tolerance volume, closely correlated with maximal squeezing pressure and/or mean resting pressure, did not differ between patients with and without chemoradiotherapy until 24 months postoperatively. Nevertheless, the urge to defecate volume was lesser in the ISR- group than in the ISR+ group at 24 months postoperatively (p = 0.022). For 301 patients in which >5 years had elapsed postoperatively, the mean 5-year local recurrence rate was 4.3 %, and the 5-year disease-free and overall survival rates were 78.9 and 92 %, respectively, without differences between the two groups.

CONCLUSIONS

Compared with uLAR without ISR, the transabdominal ISR with levator-sphincter reinforcement provides a safe resection plane with competent CRM, concurrently reduces substantial complications, and marginally promotes recovery of neorectal function.

Prognostic value of perineural invasion in colorectal cancer: a meta-analysis

BACKGROUND

The prognostic value of perineural invasion (PNI) in colorectal cancer (CRC) does not reach a consensus.

METHODS

A comprehensive literature search for relevant reports published up to October 2014 was performed using the electronic databases: PubMed, Embase, and Web of Science. The pooled hazard ratio (HR) with 95 % confidence intervals (CI) was used to estimate the prognostic effects.

RESULT

Thirty-eight studies comprising 12,661 CRC patients were analyzed. Our results showed that PNI is significantly associated with poor prognosis in OS (overall survival) (HR = 2.07, 95 % CI = 1.87-2.29, P < 0.01) and DFS (disease-free survival) (HR = 2.23, 95 % CI = 1.79-2.78, P < 0.01). There was no significant prognostic difference in DFS between stage II CRC patients with PNI(+) and stage III patients (HR = 1.67, 95 % CI = 0.53-5.25, P = 0.38). Further subgroup analysis revealed that the significance of the association between PNI and worse prognosis in CRC patients is not affected by many factors, including geographic setting, PNI positive rate, treatment, TNM stage, tumor site, and quality of the study.

CONCLUSIONS

The meta-analysis indicates that PNI is a poor prognostic factor in CRC patients. The postoperative survival of stage II CRC patients with PNI(+) is probably more similar to that of stage III patients. Currently available adjuvant therapy should be considered in stage II CRC patients with PNI(+).

Adjuvant chemotherapy for the perineural invasion of colorectal cancer

BACKGROUND

To evaluate the association of perineural invasion (PNI) with outcomes in patients after colorectal resection of colorectal cancer (CRC) and to assess the effect of PNI on the response to adjuvant chemotherapy.

PATIENTS AND METHODS

Data were retrospectively reviewed for 178 patients with consecutive stages I-III CRC who underwent curative surgery between January 1999 and December 2004. PNI data were examined, and the overall survival (OS) and disease-free survival rates were analyzed.

RESULTS

PNI was detected in 36 of 178 patients (20%) and positively correlated with lymphatic invasion (P = 0.020), venous invasion (P = 0.037), and the incidence of metastasis or recurrence (P = 0.029). Five-year disease-free survival was 46% and 68% (P < 0.001) and the 5-y OS was 64% and 80% (P < 0.001) for patients with and without PNI, respectively. In stage III CRC, multiple regression analysis identified PNI as a strong negative prognostic factor of OS; among PNI-positive patients, median OS with adjuvant chemotherapy was almost twofold higher than that without adjuvant chemotherapy (6 versus 2.8 y; P = 0.017).

CONCLUSIONS

PNI was a poor predictor of survival among patients with stage III CRC, and adjuvant chemotherapy may attenuate the adverse effects of PNI on survival.

The impact of neural invasion severity in gastrointestinal malignancies: a clinicopathological study

OBJECTIVES

Because neural invasion (NI) is still inconsistently reported and not well characterized within gastrointestinal malignancies (GIMs), our aim was to determine the exact prevalence and severity of NI and to elucidate the true impact of NI on patient's prognosis.

BACKGROUND

The union internationale contre le cancer (UICC) recently added NI as a novel parameter in the current TNM classification. However, there are only a few existing studies with specific focus on NI, so that the distinct role of NI in GIMs is still uncertain.

MATERIALS AND METHODS

NI was characterized in approximately 16,000 hematoxylin and eosin tissue sections from 2050 patients with adenocarcinoma of the esophagogastric junction (AEG)-I-III, squamous cell carcinoma (SCC) of the esophagus, gastric cancer (GC), colon cancer (CC), rectal cancer (RC), cholangiocellular cancer (CCC), hepatocellular cancer (HCC), and pancreatic cancer (PC). NI prevalence and severity was determined and related to patient's prognosis and survival.

RESULTS

NI prevalence largely varied between HCC/6%, CC/28%, RC/34%, AEG-I/36% and AEG-II/36%, SCC/37%, GC/38%, CCC/58%, and AEG-III/65% to PC/100%. NI severity score was uppermost in PC (24.9±1.9) and lowest in AEG-I (0.8±0.3). Multivariable analyses including age, sex, TNM stage, and grading revealed that the prevalence of NI was significantly associated with diminished survival in AEG-II/III, GC, and RC. However, increasing NI severity impaired survival in AEG-II/III and PC only.

CONCLUSIONS

NI prevalence and NI severity strongly vary within GIMs. Determination of NI severity in GIMs is a more precise tool than solely recording the presence of NI and revealed dismal prognostic impact on patients with AEG-II/III and PC. Evidently, NI is not a concomitant side feature in GIMs and, therefore, deserves special attention for improved patient stratification and individualized therapy after surgery.

Prognostic significance of the concomitant existence of lymphovascular and perineural invasion in locally advanced gastric cancer patients who underwent curative gastrectomy and adjuvant chemotherapy

OBJECTIVE

In this study, we evaluated the prognostic significance of the concomitant existence of lymphovascular invasion and perineural invasion in patients with advanced gastric cancer.

METHODS

A total of 206 consecutive patients with Stage II or III gastric cancer who underwent curative D2 gastrectomy and adjuvant chemotherapy from April 2004 to December 2011 were analyzed. Patients were classified into four groups according to the presence (+) or absence (-) of lymphovascular invasion and perineural invasion: lymphovascular invasion-/perineural invasion- (n = 33), lymphovascular invasion+/perineural invasion- (n = 31), lymphovascular invasion-/perineural invasion+ (n = 54) and lymphovascular invasion+/perineural invasion+ (n = 88).

RESULTS

A total of 136 patients (66.0%) received 5-fluorouracil plus cisplatin adjuvant chemotherapy and 70 patients (34.0%) received TS-1. During the median follow-up period of 35.18 months, the median disease-free survival times for lymphovascular invasion-/perineural invasion-, lymphovascular invasion+/perineural invasion- and lymphovascular invasion-/perineural invasion+ were not reached at the time of analysis; however, median disease-free survival for lymphovascular invasion+/perineural invasion+ was the worst (36.73 months, P = 0.001). The median overall survival in the four groups was also not reached at the time of analysis; however, median overall survival with lymphovascular invasion+/perineural invasion+ was the poorest (P = 0.002). In a multivariate analysis, lymphovascular invasion+/perineural invasion+ was an independent prognostic factor for both disease-free survival (hazard ratio = 1.940, 95% confidence interval 1.157-3.252, P = 0.012) and overall survival (hazard ratio = 2.973, 95% confidence interval 1.561-5.662, P = 0.001).

CONCLUSIONS

The concomitant existence of lymphovascular and perineural invasion has a significant prognostic impact on disease-free survival and overall survival in patients with Stage II or III gastric cancer.

Prognostic significance of perineural invasion in stage IIA colon cancer

BACKGROUND

Perineural invasion (PNI) may influence the prognosis of colon cancer, but little is known about its predictive value. The aim of this study was to reveal the role of PNI in predicting prognosis after curative resection of colon cancer, especially T3N0.

METHODS

Two hundred and fifty-five patients who underwent curative resection for colon cancer at Samsung Medical Center and were later diagnosed with stage T3N0 by a pathological report between November 2004 and December 2007 were retrospectively recruited into the study.

RESULTS

Among the 255 patients, 156 were male and 99 were female. The mean age was 61 years (range, 25 to 88 years). The most common tumour location was the sigmoid colon (93 patients, 36.5%). The median follow-up period was 61 months (range, 1 to 98 months). PNI was detected in 18 patients (7.1%). Adjuvant chemotherapy was performed in 205 patients (80.4%). The 5-year disease-free survival rate was greater for patients with PNI negative tumours compared with those with PNI positive tumours (92.0% versus 76.0%, P = 0.025). Adjuvant chemotherapy was not associated with significant differences in survival rate (94.8% versus 96.9%, P = 0.625). On multivariate analysis, PNI was an independent prognostic factor for disease-free and overall survival (P = 0.046, hazard ratio (HR) = 3.113, 95% confidence interval (CI) = 1.020-9.505 and P = 0.019, HR = 9.395, 95% CI = 1.453-60.755 respectively).

CONCLUSIONS

PNI is the only significant prognostic factor affecting disease-free and overall survival in patients with T3N0 colon cancer.

Histogenesis and prognostic value of myenteric spread in colorectal cancer: a Japanese multi-institutional study

BACKGROUND

The histogenesis of the pattern of cancer spread along Auerbach's plexus (myenteric spread: MS) remains unclear and its prognostic value in colorectal cancer (CRC) has not been thoroughly investigated.

METHODS

Pathology slides of 2845 pT2/pT3/pT4 CRCs stained with hematoxylin-eosin (H&E) were reviewed at 10 institutions. MS was classified into 2 groups depending on whether it was accompanied by the finding of perineural invasion (PN) within the lesion. In addition, immunohistochemical staining (D2-40, S100, CD56, synaptophysin) was performed for serially sectioned specimens from 50 CRCs diagnosed as having PN-negative MS.

RESULTS

MS was observed in 504 patients (17.7 %); 360 patients were classified as having PN-positive MS and 144 as having PN-negative MS. The 5-year disease-free survival rate of patients with MS was lower than that of patients without MS (63.3 vs 82.7 %, P < 0.0001); however, there was no significant difference in survival outcome according to the presence or absence of intralesion PN in MS. Multivariate analysis showed that the prognostic impact of MS was independent of conventional prognosticators including T and N stages, vascular invasion and extramural PN. In all the tumors having PN-negative MS, remnants of neural tissue were identified within or around cancer nests located at the leading edge of MS.

CONCLUSIONS

MS is an important prognostic factor for CRC. This feature is the result of cancer development with replacement of Auerbach's plexus and can be classified as intramural PN. The clinical significance of "Pn1" in the UICC/AJCC TNM classification could be enhanced by individual assessment both intramurally and extramurally.

Prognostic significance of lymphovascular or perineural invasion in patients with locally advanced colorectal cancer

BACKGROUND

This study was designed to evaluate the prognostic significance of the positivity of lymphovascular (LVI) and perineural invasion (PNI) in patients with locally advanced colorectal cancer.

METHODS

From January 1999 to December 2009, 1,437 consecutive patients who underwent curative surgery for stage II or III colorectal cancer were analyzed. Patients were then categorized into 4 groups: LVI-/PNI- (n = 850), LVI+ only (n = 178), PNI+ only (n = 271), and LVI+/PNI+ (n = 138).

RESULTS

With a median follow-up period of 56 months, the 5-year overall survival rates of patients with LVI-/PNI-, LVI+ only, PNI+ only, and LVI+/PNI+ were 82%, 73%, 71%, and 56%, respectively (P < .001), and the 5-year disease-free survival rates of patients with LVI-/PNI-, LVI+ only, PNI+ only, and LVI+/PNI+ were 80%, 70%, 65%, and 46%, respectively (P < .001). In multivariate analysis, LVI+/PNI+ was an independent prognostic factor for both overall survival (P < .001) and disease-free survival (P < .001).

CONCLUSIONS

Positivity of both LVI and PNI is a strong predictor of overall and disease-free survival in patients with stages II and III colorectal cancer.

The severity of neural invasion is associated with shortened survival in colon cancer

PURPOSE

Neural invasion (NI) is a histopathologic feature of colon cancer that receives little consideration. Therefore, we conducted a morphologic and functional characterization of NI in colon cancer.

EXPERIMENTAL DESIGN

NI was investigated in 673 patients with colon cancer. Localization and severity of NI was determined and related to patient's prognosis and survival. The neuro-affinity of colon cancer cells (HT29, HCT-116, SW620, and DLD-1) was compared with pancreatic cancer (T3M4 and SU86.86) and rectal cancer cells (CMT-93) in the in vitro three-dimensional (3D)-neural-migration assay and analyzed via live-cell imaging. Immunoreactivity of the neuroplasticity marker GAP-43, and the neurotrophic-chemoattractant factors Artemin and nerve growth factor (NGF), was quantified in colon cancer and pancreatic cancer nerves. Dorsal root ganglia of newborn rats were exposed to supernatants of colon cancer, rectal cancer, and pancreatic cancer cells and neurite density was determined.

RESULTS

NI was detected in 210 of 673 patients (31.2%). Although increasing NI severity scores were associated with a significantly poorer survival, presence of NI was not an independent prognostic factor in colon cancer. In the 3D migration assay, colon cancer and rectal cancer cells showed much less neurite-targeted migration when compared with pancreatic cancer cells. Supernatants of pancreatic cancer and rectal cancer cells induced a much higher neurite density than those of colon cancer cells. Accordingly, NGF, Artemin, and GAP-43 were much more pronounced in nerves in pancreatic cancer than in colon cancer.

CONCLUSION

NI is not an independent prognostic factor in colon cancer. The lack of a considerable biologic affinity between colon cancer cells and neurons, the low expression profile of colonic nerves for chemoattractant molecules, and the absence of a major neuroplasticity in colon cancer may explain the low prevalence and impact of NI in colon cancer.

Localization of nerve fibers in colonic polyps, adenomas, and adenocarcinomas by immunocytochemical staining for PGP 9.5

BACKGROUND

PGP 9.5 is a cytoplasmic protein and is a specific marker for neurites and neurons.

AIMS

Using anti-PGP 9.5, this study aimed to localize nerve fibers in normal colons, polyps, adenomas and adenocarcinomas.

METHODS

Colonic polyps, adenomas and T(1) to T(3) adenocarcinomas with adjacent normal colon were immunostained for PGP 9.5 using rabbit anti-PGP 9.5.

RESULTS

In normal colon, numerous nerve fibers were localized in inner and outer muscles, from which submucosa and lamina propria were innervated. In hyperplastic polyps and tubular adenomas, the stalk revealed Meissner's plexus and large-diameter nerve fibers, and fine nerve fibers innervated abundantly in lamina propria of hyperplastic polyps and small tubular adenomas. In villous adenomas, large-diameter nerve fibers and Meissner's plexus were localized in the stalk whereas a few or no fine nerve fibers were localized in fine stroma. In adenocarcinomas, more fine fibers were localized in submucosal stroma adjacent to the invading carcinoma in T(1) carcinomas but there were no nerve fibers in the midst of tumors in T(2) and T(3) carcinomas. There were focally and sporadically increased nerve fibers adjacent to invading cancer nests in 5 of 8 T(2) cases. In T(3) carcinomas, fragmented Auerbach's plexus were noted in cancer-invaded colonic muscles and there were no increased fine nerve fibers in the cancer-invaded subserosa in the majority of cases. PGP 9.5 immunostaining revealed tumor-associated neurogenesis in submucosa but no obviously increased nerve fibers within cancer-invaded muscles.

CONCLUSIONS

This lack of tumor-associated neurogenesis supports insidious and often silent clinical presentation of colonic carcinomas until invading through the colonic wall to adjacent organs.

The severity of neural invasion is a crucial prognostic factor in rectal cancer independent of neoadjuvant radiochemotherapy

OBJECTIVE

To provide a comprehensive characterization of neural invasion (NI) in rectal adenocarcinoma (RC), to establish a novel NI-severity scoring system, and to assess the prognostic value of NI with emphasis on its localization and severity.

BACKGROUND

The literature merely contains small-scale studies with limited histopathological characterization of NI in RC.

METHODS

Neural invasion was thoroughly characterized in 296 patients with locally advanced uT3-RC (139 with primary resection and 157 with neoadjuvant radiochemotherapy [nRCTx]). To identify the precise localization of NI, we investigated the main tumor, peritumoral area, adjacent normal tissue, and all lymph nodes. To classify the clinical impact of NI, an NI severity score was established and related to patient prognosis.

RESULTS

Neural invasion was detected in 32% of patients with primary resection and in 19% (P = 0.010) receiving nRCTx. The major location of NI was found in the peritumoral area. The prevalence of NI in the main tumor within the primary resection group was 6%, whereas it was absent in the nRCTx group (P = 0.002). Increasing NI severity, but not NI localization, was associated with a significantly poorer survival and increased local recurrence rate in both groups. Multivariate analysis (including TNM-stage, grading, and Carcinoembryonic antigen (CEA)) revealed NI prevalence and severity as independent prognostic factors.

CONCLUSIONS

Neural invasion in RC has a heterogeneous appearance in regard to its localization and its severity. nRCTx seems to have a suppressive effect on NI. Neural invasion severity might be applied as a novel tool to estimate accurately patient's prognosis and thus should be considered in pathology reports.

Perineural invasion in pT3N0 rectal cancer: the incidence and its prognostic effect

BACKGROUND

The authors' purpose was to explore the incidence and prognostic significance of perineural invasion (PNI) in pT3N0 rectal cancer.

METHODS

Pathologic materials from resected specimens of 173 patients with pT3N0 rectal cancer were retrospectively collected. PNI-positivity was categorized into 2 groups: surrounding the nerve sheath (SS-PNI) and invading through the nerve sheath (TS-PNI). The rate of PNI-positivity was compared with PNI as initially recorded in the original reports. Patients' outcome was studied in groups with different PNI status, and multivariate analysis was performed to determine its prognostic value.

RESULTS

In this retrospective analysis, PNI-positivity was found in 24.3% of all cases, in which SS-PNI and TS-PNI were 11% and 13.3%, respectively, and was related to lymphovascular invasion. Only 7.5% of patients' specimens were reported as PNI-positive in the original reports. Detection of SS-PNI was likelier to be missed than TS-PNI. The rates of local recurrence, disease-free survival, and overall survival at 5 years were similar between the groups of SS-PNI and TS-PNI. The 5-year local recurrence rate was more than 2.5-fold higher in the PNI-positive group compared with the PNI-negative group (22.7% vs 7.9%, respectively; P = .017). Multivariate analysis proved that PNI-positivity was the only independent risk factor for predicting 5-year local recurrence rate, whereas only sampled lymph nodes was related to 5-year disease-free survival and overall survival.

CONCLUSIONS

PNI is a common pathologic feature in rectal cancer. The definition of PNI should include SS-PNI and TS-PNI. Rectal cancer patients who are PNI-positive are at higher risk of local recurrence and should be considered for more intensive treatment.

Long-term survival and recurrence outcomes following surgery for distal rectal cancer

BACKGROUND

Treatment of distal rectal cancer remains clinically challenging and includes proctectomy and coloanal anastomosis (CAA) or abdominoperineal resection (APR). The purpose of this study is to evaluate operative and pathologic factors associated with long-term survival and local recurrence outcomes in patients treated for distal rectal cancer.

METHODS

A retrospective consecutive cohort study of 304 patients treated for distal rectal cancer with radical resection from 1993 to 2003 was performed. Patients were grouped by procedure (CAA or APR). Demographic, pathologic, recurrence, and survival data were analyzed utilizing chi-square analysis for comparison of proportions. Survival analysis was performed using Kaplan-Meier method and log-rank test for univariate and Cox regression for multivariate comparison.

RESULTS

The median tumor distance from the anal verge was 2 cm [interquartile range (IQR) 0.5-4 cm]. Margins were negative in all but four patients (one distal, 0.3%; three radial, 1%). The 5-year overall survival rate was 82% (88.6% stage pI, 80.5% stage pII, 67.9% stage pIII). Older age, advanced pathologic stage, presence of lymphovascular or perineural invasion, earlier treatment period, and APR surgery type were associated with worse survival on multivariate analysis. The 5-year local recurrence rate was 5.3% after CAA and 7.9% after APR (p = 0.33).

CONCLUSIONS

Low rates of local recurrence and good overall survival can be achieved after treatment of distal rectal cancer with stage-appropriate chemoradiation and proctectomy with CAA or APR. Sphincter preservation can be achieved even with distal margins less than 2 cm.

Prognostic factors in node-negative colorectal cancer: a retrospective study from a prospective database

PURPOSE

There is a need to identify a subgroup of high-risk patients with node-negative colorectal cancer who have a poor long-term prognosis and may benefit from adjuvant therapies. The aim of this study was to evaluate the prognostic impact of clinical and pathological parameters in a retrospective study from a prospective, continuous database of homogenously treated patients.

METHODS

This study included 362 patients operated in a single institution for Dukes A and B (node-negative) colorectal cancer. The median follow-up was 140 months. The prognostic value of 13 clinical and pathological parameters was investigated.

RESULTS

Multivariate analysis identified six independent prognostic factors: age at time of diagnosis (hazard ratio (HR) = 1.076), number of lymph nodes removed (HR = 0.948), perineural invasion (HR = 2.173), venous invasion (HR = 1.959), lymphatic vessel invasion (HR = 2.126), and T4 stage (HR = 5.876).

CONCLUSION

These parameters could be useful in identifying patients with high-risk node-negative colorectal cancer who should be presented to adjuvant therapy.

Rationale of pelvic autonomic nerve preservation in rectal cancer surgery based on immunohistochemical study

PURPOSE

Previous studies revealed that the incidence of cancer cell involvement along the pelvic autonomic nerves ranged from 4 to 14%. However, patients' profiles and methodologies differed among the studies. This study was conducted to clarify the incidence of cancer cell involvement in and around the pelvic autonomic nerves immunohistochemically.

METHODS

Immunohistochemical staining was performed on pelvic autonomic nerve specimens resected from 17 patients with p-Stage I-III lower rectal cancers. Antibodies used were pan-cytokeratin (AE1/AE3) for staining cancer cells, S-100 for autonomic nerves, and D2-40 for lymphatic vessels. Lymphatic permeation around the pelvic autonomic nerves was defined as present when AE1/AE3-positive cells were detected in D2-40-stained lymphatic vessels. The presence of metastasis to the interstitial tissue or contaminants was also recorded.

RESULTS

TNM staging was stage I in 1, stage II in 5, and stage III in 11 cases, respectively. No cases had lymphatic permeation or metastasis to the interstitial tissue in and around the pelvic autonomic nerves. Cancer cell contaminants were seen in four cases (23%). In three cases (18%), metastatic nodes were located at the root of the middle rectal artery, very close to the pelvic autonomic nerves.

CONCLUSIONS

Cancer cell involvement was not seen in and around the pelvic autonomic nerves, suggesting that complete pelvic autonomic nerve preservation may be feasible, unless nerves are invaded by the tumor. In some cases, however, metastatic nodes were seen very close to the nerves. Meticulous lymph node dissection along the pelvic autonomic nerves is mandatory.

Prognostic value of perineural invasion in patients with stage II colorectal cancer

BACKGROUND

Perineural invasion (PNI) may influence the prognosis after resection of colorectal cancer (CRC); whether this is a definite prognostic factor remains controversial. This study determined the clinicopathologic factors associated with oncologic outcome after radical resection of stage II CRC, focusing on PNI.

MATERIALS AND METHODS

We retrospectively reviewed 341 consecutive patients who underwent curative surgery for stage II CRC between January 2001 and December 2006. Of these, 278 patients (81.5%) received postoperative 5-fluorouracil-based chemotherapy. The oncologic outcomes and the risk factors for recurrence were analyzed.

RESULTS

PNI was detected in 57 of 341 patients (16.7%) and was significantly associated with depth of tumor invasion (P = .035) and positive lymphovascular invasion (P < .001). Multivariate analyses revealed that PNI was a significant independent prognostic factor for disease-free survival, not for overall survival. With a median follow-up period of 57.6 months, the 5-year disease-free and overall survival rates of the patients were 80.2 and 82.6%, respectively. The 5-year disease-free survival of the PNI-negative group was significantly higher than that of the PNI-positive group (P < .001). Within the PNI-positive patients, those receiving chemotherapy had significantly higher 5-year disease-free survival than the others (P = .023).

CONCLUSION

This study illustrates the value of PNI as a prognostic factor for stage II CRC. Moreover, PNI-positive patients should be considered for postoperative chemotherapy.

Correlação de fatores anatomopatológicos com a sobrevida de pacientes operados por adenocarcinoma colorretal

OBJETIVO: Avaliar a influência de fatores anatomopatológicos como prognóstico na sobrevida de pacientes operados de adenocarcinoma colorretal. MÉTODOS: Estudo tipo coorte histórica aberta, baseado na análise de 119 pacientes operados de adenocarcinoma colorretal com intenção curativa no Hospital Universitário Júlio Muller, no período de 1984 a 2002. Os dados foram obtidos dos prontuários médicos e de exames anatomopatológicos revisados, sendo submetidos à análise estatística de sobrevida em cinco anos pelo método de Kaplan & Méier. O reto foi o segmento mais acometido em 44,5% dos casos. O aspecto macroscópico tumoral predominante foi o ulcerado ou infiltrante (50,4%), com tamanhos entre 2 e 17 cm, sendo que a maioria dos tumores (64,7%) infiltrava até a camada serosa. O número médio de linfonodos analisados foi de 11,8(±7,3) por peça cirúrgica, indentificando-se nestes, 42,8% de metástases. A maioria dos tumores (85,4%) era bem ou moderadamente diferenciada. Foram observadas embolização angiolinfática e perineural em respectivamente 51,2% e 23,5%. RESULTADOS: Não houve significância estatística quanto a morfologia (p=0,87), tamanho do tumor (p=0,56) e grau de diferenciação celular (p=0,83). Os fatores que se correlacionaram com a sobrevida foram o sítio do tumor primário (p=0,04), a invasão angiolinfática intra-tumoral (p=0,02), invasão perineural (p<0,01), a infiltração das camadas (p=0,02), e o comprometimento linfonodal (p<0,01). CONCLUSÃO: A análise dos fatores anatomopatológicos mostrou correlação significativa da sobrevida com o sítio primário, a camada acometida, invasão perineural, invasão angiolinfática e comprometimento dos linfonodos.