Direct tumor invasion in colon cancer: correlation with tumor spread and survival

Prophylactic hyperthermic intraperitoneal chemotherapy in T4 colorectal cancer: Can it improve the oncologic prognosis? - A propensity score matching study

BACKGROUND

Some studies show that cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) may improve overall survival and is a possible curative treatment for selected colorectal cancer (CRC) patients with restricted peritoneal metastasis (PM). The value of HIPEC in preventing PM of CRC is still controversial.

MATERIALS AND METHODS

In this retrospective propensity score matching (PSM) cohort study, all patients with cT4N0-2M0 undergoing treatment at a single institution in China (2014-2018) were reviewed. The 3-year disease-free survival (DFS) was set as the primary outcome, and the 3-year PM rate was also analyzed.

RESULTS

220 patients were included in this study for analysis. After 1:3 PSM: HIPEC (n = 45) and No HIPEC (n = 135). Through analysis, it was found that prophylactic HIPEC correlated to better DFS [hazard ratio (HR) 0.43, 95 % confidence interval (CI) 0.19-0.95; p = 0.037], and N2 stage correlated to worse DFS [HR 1.97, 95 % CI 1.09-3.56; p = 0.025]. For laparoscopic surgery subgroup analyses, 3-year PM rate of patients with laparoscopic surgery was 13.8 % in No HIPEC group, and 2.6 % in HIPEC group (p = 0.070). Besides, no post-operative death occurred, the anastomotic leakage rate was 2.2 % in HIPEC group and 0.7 % in the control group (p = 0.439).

CONCLUSIONS

Prophylactic HIPEC may improve the prognosis in patients with cT4N0-1M0 CRC, but not in cT4N2M0 CRC, and it does not significantly increase surgery-related complications. Laparoscopic surgery followed by HIPEC for T4 stage CRC may not increase risk of PM.

Prognostic significance of additional histologic features for subclassification of pathological T3 colon cancer

BACKGROUND

Additional histologic features of T3 colon cancer, such as tumour depth invasion beyond muscularis propria and elastic lamina invasion (ELI), have taken interest for a more accurate staging.

METHODS

Patients with pT3 and pT4a (control group) colon adenocarcinoma were retrospectively collected from our institutional database. The study group was divided according to depth of tumour invasion < 5 mm and ≥ 5 mm, and into ELI - and ELI + . Chi-square test was used to compare the clinicopathological characteristics. OS and DFS were estimated using Kaplan-Meier method and compared with the log-rank test. Univariable and multivariable Cox proportional hazard models were employed to assess the effect on OS and DFS.

RESULTS

Out of 290 pT3 tumours, 168 (58%) had a depth of tumour invasion < 5 mm and 122 (42%) ≥ 5 mm. The 5-year OS and DFS were 85.2, 68.7 and 60.9%, and 81.4, 73.9 and 60.1% in pT3 < 5 mm, pT3 ≥ 5 mm, and pT4a respectively (p = 0.001, p = 0.072). Considering ELI - (n = 157, 54%) and ELI + (n = 133, 46%), the 5-year OS and DFS were 78.9, 76.7, and 60.9%, and 75.5, 81.5, and 60.1% in ELI  - , ELI + and pT4a respectively (p = 0.955, p = 0.462). At multivariable analysis, the depth of invasion was found to be an independent predictive factor for OS (HR 2.04, 95%CI 1.28-3.24, p = 0.003) and DFS (HR 1.98, 95%CI 1.24-3.18, p = 0.004), while ELI did not result a prognostic factor for OS nor DFS.

CONCLUSION

In pT3 colon cancer, depth of tumour invasion ≥ 5 mm is an independent risk factor for OS and DFS, whereas ELI did not result a prognostic factor affecting OS nor DFS.

Beclin 1 and LC3 as predictive biomarkers for metastatic colorectal carcinoma

Autophagy is a highly conserved self-destructive process that disassembles dysfunctional or unnecessary cellular components. It plays an important role in cancer metastasis, which is of particular interest considering metastatic disease is the major cause of colorectal carcinoma (CRC) related mortality. Here, we investigated the immunohistochemical expression of autophagy-related protein Beclin 1 and Microtubule-associated protein 1A/1B-light chain 3 (LC3) within surgical CRC specimens, first in a training cohort (205 patients), then in an inner validation cohort (160 patients) and an independent cohort (161 patients). The expressions of Beclin 1 and LC3 were lower in metastatic CRC compared with non-metastatic CRC. Furthermore, we developed an autophagy-based classifier for metastatic prediction. This classifier, including Beclin 1, LC3 and carcinoembryonic antigen (CEA) level, resulted in 82.9% sensitivity and 89.8% specificity for metastatic detection in the training cohort. In the independent cohort, it achieved 77.9% sensitivity and 90.3% specificity in predicting the metastasis of CRC. These results suggested that low expression of Beclin 1 and LC3 contributed to a more aggressive cancer cell phenotype, and our autophagy-based classifier was a reliable tool for metastatic prediction in CRC.

Local staging of sigmoid colon cancer using MRI

Background

An accurate radiological staging of colon cancer is crucial to select patients who may benefit from neoadjuvant chemotherapy.

Purpose

To evaluate the diagnostic accuracy of preoperative magnetic resonance imaging (MRI) in identifying locally advanced sigmoid colon cancer, poor prognostic factors, and the inter-observer variation of the tumor apparent diffusion coefficient (ADC) values of diffusion-weighted imaging (DWI).

Material and Methods

Using 1.5 T MRI with high resolution T2-weighted (T2W) imaging, DWI, and no contrast enhancement, 35 patients with sigmoid colon cancer were assessed. T-stage, N-stage, extramural vascular invasion (EMVI), and ADC values of the tumors were assessed and blindly compared by two observers using postoperative histopathological examination as the gold standard. Early tumors were defined as T1 to T3ab, and advanced tumors as T3cd or T4.

Results

The accuracy of the two radiologists in staging early versus advanced tumors, N-stage, and identification of EMVI was 94%/89%, 60%/66%, and 77%/60% with an inter-observer agreement of к = 0.86 (95% confidence interval [CI] = 0.67–1.00), к = 0.64 (95% CI = 0.39–0.90), and к = 0.52 (95% CI = 0.23–0.80). All the measured mean ADC values were below 1.0 × 10⁻³ mm²/s with an intra-class correlation coefficient in T3cd–T4 tumors of 0.85.

Conclusion

Preoperative MRI can identify locally advanced sigmoid colon cancer and has potential as the imaging of choice to select patients for neoadjuvant chemotherapy. Initial experience with ADC measurement was achieved with an excellent inter-observer agreement in advanced tumors.

[Endoscopic surgery]

Endoscopic surgery of the stomach/gastrointestinal tract was developed in the 1990s in Japan as a minimally invasive method of removing early-stage tumours, using a gastro-/coloscope instead of open or laparoscopic surgery. Its advantages are obvious, in that the patient is spared more major surgery, the hospital saves on resources as well as admission to a ward, and society is spared the costs of days of sickness absence. Endoscopic submucosal dissection is considered the most difficult technique, but it allows for the accurate dissection of large tumours. In 1999, Japanese surgeon Takuji Gotoda and his team were the first to perform these types of dissections of early cancers in the rectum using a diathermic needle and a flexible scope.

Regional Lymph Nodes Status and Ratio of Metastatic to Examined Lymph Nodes Correlate with Survival in Stage IV Colorectal Cancer

BACKGROUND

Although lymph nodes status and the ratio of metastatic to examined lymph node (LNR) are important prognostic factors in early-stage colorectal cancer (CRC), their significance in patients with metastatic disease remains unknown. The study aims to determine prognostic importance of nodal status and LNR in patients with stage IV CRC.

METHODS

A cohort of 1109 eligible patients who were diagnosed with synchronous metastatic CRC in Saskatchewan during 1992-2010 and underwent primary tumor resection was evaluated. We conducted the Cox proportional multivariate analyses to determine the prognostic significance of nodal status and LNR.

RESULTS

Median age was 70 years (22-98) and M:F was 1.2:1. Rectal cancer was found in 26 % of patients; 96 % had T3/T4 tumor, and 82 % had node positive disease. The median LNR was 0.36 (0-1.0). Fifty-four percent received chemotherapy. Median overall survival of patients who had LNR of <0.36 and received chemotherapy was 29.7 months (95 % CI 26.6-32.9) compared with 15.6 months (95 % CI 13.6-17.6) with LNR of ≥0.36 (P < .001). On multivariate analyses, no chemotherapy (HR 2.36 [2.0-2.79]), not having metastasectomy (HR 1.94 [1.63-2.32]), LNR ≥0.36 (HR 1.59 [1.38-1.84]). nodal status (HR 1.34 [1.14-1.59]), and T status (HR 1.23 [1.07-1.40]) were correlated with survival. Test for interaction was positive for LNR and high-grade cancer (HR 1.51 [1.10-2.10]).

CONCLUSIONS

Our results suggest that nodal status and LNR are important prognostic factors independent of chemotherapy and metastasectomy in stage IV CRC patients.

Tumour Microenvironment: Overview with an Emphasis on the Colorectal Liver Metastasis Pathway

The tumour microenvironment (TME) represents a dynamic network that plays an important role in tumour initiation, proliferation, growth, and metastasis. Cell behaviour may be regulated by interplay of molecular interactions involving positive and negative reinforcement as well as a high level of cross-talk, which determines this system. Additionally, cancer involves cell proliferation, its malignancy defined by the tumour's ability to break down normal tissue architecture and by a dynamic process of invasion and metastasis. The metastatic cascade is regulated by a chain of molecular steps which triggers the progression of the developing cancer cell in the primary tumour into a number of transformations, leading to invasion and proceeding to metastases. Tumour-associated macrophages (TAMs) play a key-role in the progression from inflammatory conditions to cancer; TAMs are also capable of infiltrating the tumour microenvironment. Furthermore, myeloid-derived suppressor cells (MDSCs), a population of inhibitory immune cells, have been reported to increase in various cancer types, although characterising human MDSCs remains difficult, as their phenotype is quite variable. The future of cancer treatment is likely to involve creating more drugs that target these elements as well as others. An overview of the tumour's microenvironment is, therefore, presented in this paper, focusing on the metastatic pathways of primary colorectal cancer to the liver.

Correlations of tumor-associated macrophage subtypes with liver metastases of colorectal cancer

OBJECTIVE

This work aimed to investigate the correlations of tumor-associated macrophages (TAMs) and their subtypes M1 and M2 with liver metastasis of colorectal cancer, and provide useful references for seeking predictors of liver metastasis and studying mechanisms.

METHODS

120 patients with colorectal cancer from 2000 to 2009 were divided into low, middle and high liver metastasis groups (group A, B and C, respectively). S-P immunohistochemical staining and microscopic observation were conducted to compare expression in CD68- positive cells (TAMs), CD80-positive cells (M1) and CD163-positive cells (M2) in three groups. Correlations of TAMs, M1, M2, and M2/M1 ratio with clinical and pathological parameters were analyzed.

RESULTS

With increase of liver metastatic ability, the number of TAMs decreased gradually, with no significant difference between any two of the three groups (P > 0.05), while the numbers of M1 and M2 were significantly decreased and increased, respectively, with significant difference between any two of three groups (P < 0.05 or P < 0.01). In addition, the M2/M1 ratio increased with increase of liver metastatic ability (P < 0.01). There was no statistical significance of correlation of TAMs with each clinical and pathological parameter. M1 was negatively related with lymphatic metastasis and liver metastatic ability. M2 was positively correlated with preoperative CEA level, lymphatic metastasis, tumor differentiation degree and liver metastatic ability. The same was the case for the M2/M1 ratio.

CONCLUSIONS

Effects of TAMs on liver metastasis of colorectal cancer do not depend on the total number of TAMs, but on the number and proportion of functional subtypes M1 and M2. M2 number and M2/ M1 ratio are more accurate predictors for liver metastasis of colorectal cancer.

Selection of colon cancer patients for neoadjuvant chemotherapy by preoperative CT scan

OBJECTIVE

Preoperative staging is essential to plan correct treatment of colon cancer and calls for objective, accurate methods for the introduction of neoadjuvant chemotherapy, which represents a new treatment option.

PURPOSE

To evaluate the diagnostic accuracy of multislice computed tomography (CT) in local staging of colon cancer correlated with histopathological parameters, including criteria for adjuvant chemotherapy.

MATERIAL AND METHODS

A total of 74 included patients had preoperative CT scans and surgical resection of their colon tumors. Tumor stage (T-stage), extramural tumor invasion (ETI), nodal stage (N-stage), extramural venous invasion (EVI) and the distance from tumor to nearest retroperitoneal fascia (DRF) were retrospectively assessed on the CT scan and compared blindly with the results of the pathological examination, including evaluation of the criteria for adjuvant chemotherapy. Advanced tumors were defined as T3 with ETI ≥5 mm or T4.

RESULTS

Sixty-nine percent of the tumors were correctly T-staged by CT, 7% were overstaged and 24% were understaged. As to correct recognition of ETI on the CT scan, the observer was 73% accurate compared with histology (70% sensitivity (95% CI: 53-82%), 78% specificity (95% CI: 60-90%), 81% positive predictive value (PPV) (95% CI: 63-91%) and 66% negative predictive value (NPV) (95% CI: 49-80%). N-stage, EVI and DRF had poor accuracy: 53%, 53% and 64%. All patients with advanced tumors on CT fulfilled the criteria for adjuvant chemotherapy. Positive predictive value: 100% (95% CI: 88-100%).

CONCLUSION

CT has a potential in the preoperative selection of advanced tumors suitable for neoadjuvant chemotherapy without overtreatment of low-risk patients.

Short term results of complete (D3) vs. standard (D2) mesenteric excision in colon cancer shows improved outcome of complete mesenteric excision in patients with TNM stages I-II

BACKGROUND

The aim of the present study was to investigate whether the new method of complete mesocolic excision (CME) with a high (apical) vascular tie (D3 resection) had an immediate effect compared with a conventional (standard) approach even in those patients without lymph node metastases.

METHODS

A cohort of 189 consecutive patients with tumour-nodal-metastasis (TNM) stages I-II and a mean age of 73 years were operated on in the period from January 2007 to December 2008 in three community teaching hospitals. The CME approach (n = 89), used in hospital A, was compared to the standard technique used (n = 105) in two other hospitals, B and C. Lymph node yields from the specimens were used as a surrogate measure of radical resections. Outcome was analysed after a median follow-up of 50.2 months.

RESULTS

In-hospital mortality rate was 2.8 % in the CME group and 8.6 % in the standard group. The 3-year overall survival (OS) in the CME group was 88.1 versus 79.0 % (p = 0.003) in the standard group, and the corresponding disease-free survival (DFS) was 82.1 versus 74.3 % (p = 0.026). Cancer-specific survival was 95.2 % in the CME group versus 90.5 % in the standard group (p = 0.067). Age, operative technique, and T category were significant in multiple Cox regressions of OS and DFS.

CONCLUSIONS

Compared with the standard (D2) approach, introduction of CME surgical management of colon cancer resulted in a significant immediate improvement of 3-year survival for patients with TNM stage I-II tumours as assessed by OS and DFS.

Does t3 subdivision correlate with nodal or distant metastasis in colorectal cancer?

Purpose

We analyzed the clinical data of T3 colorectal cancer patients to assess whether T3 subdivision correlates with node (N) or metastasis (M) staging and stage-independent factors.

Methods

Five hundred fifty-five patients who underwent surgery for primary colorectal cancer from January 2003 to December 2009 were analyzed for T3 subdivision. T3 subdivision was determined by the depth of invasion beyond the outer border of the proper muscle (T3a, <1 mm; T3b, 1 to 5 mm; T3c, >5 to 15 mm; T3d, >15 mm). We investigated the correlation between T3 subdivision and N, M staging and stage-independent prognostic factors including angiolymphatic invasion (ALI), venous invasion (VI) and perineural invasion (PNI).

Results

The tumors of the 555 patients were subclassified as T3a in 86 patients (15.5%), T3b in 209 patients (37.7%), T3c in 210 patients (37.8%) and T3d in 50 patients (9.0%). The nodal metastasis rates were 39.5% for T3a, 56.5% for T3b, 75.7% for T3c and 74.0% for T3d. The distant metastasis rates were 7.0% for T3a 9.1% for T3b, 27.1% for T3c and 40.0% for T3d. Both N and M staging correlated with T3 subdivision (Spearman's rho = 0.288, 0.276, respectively; P < 0.001). Other stage-independent prognostic factors correlated well with T3 subdivision (Spearman's rho = 0.250, P < 0.001 for ALI; rho = 0.146, P < 0.001 for VI; rho = 0.271, P < 0.001 for PNI).

Conclusion

Subdivision of T3 colorectal cancer correlates with nodal and metastasis staging. Moreover, it correlates with other prognostic factors for colorectal cancer.

Heterogeneity of pT3 colorectal carcinomas according to the depth of invasion

Colorectal carcinomas (CRCs) infiltrating through the muscularis propria layer without infiltration of adjacent structures, organs or the serosa-i.e. the pT3 tumors, compose the largest subset of large intestinal carcinomas treated by surgical resection. They are heterogeneous in terms of prognosis. CRCs treated by surgery in a period of 69 months were prospectively classified as pT3a tumors (invading to a maximum of 5 mm beyond the muscularis propria) and pT3b tumors (invading deeper). Their nodal status, incidence of vascular invasion and the presence or absence of distant metastases were analyzed in relation to the depth of invasion. Of the 593 CRCs primarily treated by surgery 429 were pT3 tumors. CRCs categorized as pT3a had significantly lower rates of nodal involvement (44% vs 75%), massive nodal involvement (pN2) (9% vs 39%), venous invasion (17% vs 30%) and distant metastasis (11% vs 28%) than pT3b tumors. Significant differences in these prognostic variables in pT3a and pT3b cancers were observed both for carcinomas of the colon and those of the rectum. Such differences were not obvious in further 66 ypT3 cases of rectal carcinoma receiving neoadjuvant treatment before surgery. Tumors in the pT3a category are associated with a better prognostic profile than pT3b tumors. This subdivision might be useful in both prognostication and treatment planning.

Tumor cell-microenvironment interaction models coupled with clinical validation reveal CCL2 and SNCG as two predictors of colorectal cancer hepatic metastasis

PURPOSE

This study aimed to identify novel biological markers for the prediction of colorectal cancer liver metastasis.

EXPERIMENTAL DESIGN

We established two models that mimicked the interactions between colorectal tumor cells and the liver microenvironment. From these models we established subcell lines that had an enhanced ability to metastasize to the liver. Genes that related to hepatic metastasis were screened by microarray. The candidate markers were tested by immunohistochemistry, and their predictive accuracy was assessed by the cross-validation method and an independent test set.

RESULTS

Highly metastatic colon cancer cell sublines SW1116p21 and SW1116v3 were established from the tumor cell-microenvironment interaction models. Seven of the up-regulated genes in the sublines were selected as candidate markers for predicting metastatic potential. A total of 245 colorectal cancer samples were divided into a training set containing 117 cases and a test set containing 128 cases. In the training set, immunohistochemical analysis showed CCL2 and SNCG expression was higher in the hepatic metastasis group than in the nonmetastasis group, and was correlated with poor survival. Logistic regression analysis revealed that CCL2 and SNCG levels in primary tumors, serum carcinoembryonic antigen level, and lymph node metastasis status were the only significant (P < 0.05) parameters for detecting liver metastasis. In leave-one-out-cross-validation, the two markers, when combined with clinicopathologic features, resulted in 90.5% sensitivity and 90.7% specificity for hepatic metastasis detection. In an independent test set, the combination achieved 87.5% sensitivity and 82% specificity for predicting the future hepatic metastasis of colorectal cancer.

CONCLUSION

Our results suggest that these models are able to mimic the interactions between colorectal cancer cells and the liver microenvironment, and may represent a promising strategy to identify metastasis-related genes. CCL2 and SNCG, combined with clinicopathologic features, may be used as accurate predictors of liver metastasis in colorectal cancer.