Prognostic significance of response to preoperative radiotherapy, lymph node metastasis, and CEA level in patients undergoing total mesorectal excision of rectal cancer

Overexpression of MLPH in Rectal Cancer Patients Correlates with a Poorer Response to Preoperative Chemoradiotherapy and Reduced Patient Survival

Data mining of a public transcriptomic rectal cancer dataset (GSE35452) from the Gene Expression Omnibus, National Center for Biotechnology Information identified the melanophilin (MLPH) gene as the most significant intracellular protein transport-related gene (GO:0006886) associated with a poor response to preoperative chemoradiation. An MLPH immunostain was performed on biopsy specimens from 172 rectal cancer patients receiving preoperative chemoradiation; samples were divided into high- and low-expression groups by H-scores. Subsequently, the correlations between MLPH expression and clinicopathologic features, tumor regression grade, disease-specific survival (DSS), local recurrence-free survival (LRFS), and metastasis-free survival (MeFS) were analyzed. MLPH expression was significantly associated with CEA level (p = 0.001), pre-treatment tumor status (p = 0.022), post-treatment tumor status (p < 0.001), post-treatment nodal status (p < 0.001), vascular invasion (p = 0.028), and tumor regression grade (p < 0.001). After uni- and multi-variable analysis of five-year survival, MLPH expression was still associated with lower DSS (hazard ratio (HR), 10.110; 95% confidence interval (CI), 2.178–46.920; p = 0.003) and MeFS (HR, 5.621; 95% CI, 1.762–17.931; p = 0.004). In conclusion, identifying MLPH expression could help to predict the response to chemoradiation and survival, and aid in personal therapeutic modification.

The combination of early treatment response and ypT stage is a novel metric to stage rectal cancer patients treated with neoadjuvant chemoradiotherapy

Rectal cancer patients receiving neoadjuvant chemoradiotherapy (NCRT) are currently classified using the same Tumor-Node-Metastasis staging system as those patients without NCRT. We determined whether the combination of tumor treatment response (TRG) and ypT stage more accurately assesses primary tumors in rectal cancer after NCRT. We analyzed data from 329 rectal cancer patients treated with NCRT followed by radical resection. Cox proportional hazards models were used to evaluate the effects of different staging parameters on disease-free survival (DFS). ypN stage and TRG were independently associated with 3-year DFS, but ypT stage was not. We developed a new modified T stage classification metric (M-TTRG) that categorized patients into 5 subgroups based on ypT stage and TRG, with weighting by β-coefficients from multivariate analyses. The incidence of patients developing local or distant recurrence increased with increasing M-TTRG level. All five M-TTRG classes correlated with 3-year DFS. Improvement was seen in the model with M-TTRG classification compared with ypT stage, based on area under the curve after computing receiver operating characteristic curves. Our modified ypTNM staging system significantly improved prediction of 3-year DFS. This suggests TRG could complement ypT stage, and we propose the new M-TTRG metric could be used to better classify NCRT-treated patients, thereby improving treatment and assessing prognosis. The M-TTRG metric might be applicable to other types of cancer.

Carcinoembryonic antigen as a marker of radioresistance in colorectal cancer: a potential role of macrophages

Background

We sought to identify the carcinoembryonic antigen (CEA) as a marker of radioresistance in rectal cancer.

Methods

From July 1997 to January 2008, 104 patients with stage II or III rectal cancer who were treated with post-operative radiotherapy (PORT) were included in this study. The doses of radiotherapy ranged from 45 to 54.6 Gy. The CEA levels were measured before surgery. We analyzed the actuarial rates of overall survival (OS), distant metastasis (DM), and local recurrence (LR) using Kaplan-Meier curves. Multivariate analyses were performed with Cox regression models. We used THP-1 monocyte cell lines for macrophage differentiation (M0, M1 or M2). The RNA extracted from the macrophages was analyzed via a genomic method in the core laboratory. The radiosensitivities of CEA-rich LS1034 cells were compared between cells with and without the conditioned media from CEA-stimulated macrophages.

Results

Preoperative CEA levels ≥10 ng/mL were independent predictive factors for OS (p = 0.005), DM (p = 0.026), and LR (p = 0.004). The OS rates among the patients with pretreatment CEA levels < 10 ng/mL and ≥10 ng/mL were 64.5% and 35.9% (p = 0.004), respectively. The corresponding rates of DM were 40.6% and 73.1% (p = 0.024). The corresponding rates of LR were 6.6% and 33.9% (p = 0.002). In the M0 macrophages, exogenous CEA elicited a dose-response relationship with M2 differentiation. In the CEA-stimulated M0 cells, some mRNAs were upregulated by as much as 5-fold, including MMP12, GDF15, and JAG1. In the CEA-stimulated M2 cells, a 4-fold up-regulation of GADD45G mRNA was noted. The conditioned media from the CEA-stimulated M2 cells elicited an increase in the numbers of LS180, SW620, and LS1034 cells after irradiation. CEA caused the M2 differentiation of the macrophages.

Conclusion

Pretreatment CEA levels ≥10 ng/mL are a significant risk factor for OS, DM, and LR following PORT for rectal cancer. CEA causes radioresistance in the presence of M2 macrophages. More comprehensive examinations prior to surgery and intensive adjuvant therapy are suggested for patients with CEA levels ≥10 ng/mL. Further studies of these mechanisms are needed.

Preoperative Submucosal Injection of Carbon Nanoparticles Improves Lymph Node Staging Accuracy in Rectal Cancer after Neoadjuvant Chemoradiotherapy

BACKGROUND

The aim of this study was to evaluate the association between the number of nodes harvested and the rate of node positivity, and to evaluate the effect of carbon nanoparticles (CNPs) in improving lymph node detection and staging accuracy in patients who received neoadjuvant chemoradiotherapy (NCRT) followed by curative resection.

STUDY DESIGN

Between September 2008 and June 2014, 152 consecutive rectal cancer patients treated with NCRT and curative resection were included. Forty-five patients underwent preoperative submucosal injection of CNPs (CNP group); the other patients underwent surgery only (control group). The relationship between the number of lymph nodes harvested and the rate of node positivity was investigated. A comparison of the number of harvested lymph nodes and the node positivity rate between the 2 groups was also performed. The lymph nodes in the CNP group were analyzed in detail.

RESULTS

The rate of node positivity increased gradually from 8.6% in patients with 1 to 5 nodes assessed to 37.8% in patients with 17 to 44 nodes assessed. The number of lymph nodes harvested was an independent risk factor for node positivity (p = 0.036). The mean number of lymph nodes retrieved in the CNP group was more than in the control group (21.1 vs 8.0, p = 0.000). The percentage of patients with positive lymph nodes was lower than in the control group (19.6% vs 35.6%, p = 0.037). In the CNP group, of 58 metastatic lymph nodes, 45 (77.6%) were dyed. Of 37 metastatic lymph nodes smaller than 5 mm, 33 (89.2%) were dyed.

CONCLUSIONS

More precise oncologic prognosis assessment was provided for patients with rectal cancer after NCRT by increasing the number of lymph nodes counted using a dye-tracing method, indicating that the use of CNPs is beneficial.

Identification of a DNA methylation signature to predict disease-free survival in locally advanced rectal cancer

In locally advanced rectal cancer a preoperative predictive biomarker is necessary to adjust treatment specifically for those patients expected to suffer relapse. We applied whole genome methylation CpG island array analyses to an initial set of patients (n=11) to identify differentially methylated regions (DMRs) that separate a good from a bad prognosis group. Using a quantitative high-resolution approach, candidate DMRs were first validated in a set of 61 patients (test set) and then confirmed DMRs were further validated in additional independent patient cohorts (n=71, n=42). We identified twenty highly discriminative DMRs and validated them in the test set using the MassARRAY technique. Ten DMRs could be confirmed which allowed separation into prognosis groups (p=0.0207, HR=4.09). The classifier was validated in two additional cohorts (n=71, p=0.0345, HR=3.57 and n=42, p=0.0113, HR=3.78). Interestingly, six of the ten DMRs represented regions close to the transcriptional start sites of genes which are also marked by the Polycomb Repressor Complex component EZH2. In conclusion we present a classifier comprising 10 DMRs which predicts patient prognosis with a high degree of accuracy. These data may now help to discriminate between patients that may respond better to standard treatments from those that may require alternative modalities.

Prognostic value of pretreatment level of carcinoembryonic antigen on tumour downstaging and early occurring metastasis in locally advanced rectal cancer following neoadjuvant radiotherapy (30 Gy in 10 fractions)

AIM

To evaluate the role of carcinoembryonic antigen (CEA) in predicting the response to and prognosis for locally advanced rectal cancer treated with 30 Gy neoadjuvant radiotherapy (nRT) in 10 fractions (30 Gy/10 f).

METHOD

This retrospective study involved 240 patients with locally advanced rectal cancer who underwent 30 Gy/10 f nRT (biologically equivalent dose 36 Gy) followed by total mesorectal excision between August 2003 and 2009. Serum CEA level was determined before administration of nRT. The prognostic value of serum CEA level on tumour downstaging and 3-year disease-free survival was analysed.

RESULTS

Ninety out of 240 (37.5%) patients had elevated CEA levels before nRT. The incidence of T downstaging in patients decreased significantly as the pretreatment CEA levels became more elevated (< 5 ng/ml, 50.7%; 5-10 ng/ml, 39.5%; > 10 ng/ml, 17.3%; P = 0.00014). Downstaging to ypCR or ypStage I occurred in 46.7% (66/150) of patients with a CEA level of < 5 ng/ml and 34.2% (13/38) of patients with a CEA level of 5-10 ng/ml. In contrast, just 13.5% (7/52) of those with a CEA level > 10 ng/ml downstaged to ypStage I and none of them achieved ypCR, with statistical difference (P = 0.001). A significantly higher incidence of early metastasis (within 6 postoperative months) was observed with increasing CEA level: 2.0% (3/150), 5.4% (2/38) and 11.5% (6/52) in patients with CEA level < 5 ng/ml, 5-10 ng/ml or > 10 ng/ml, respectively (P = 0.018).

CONCLUSION

Pretreatment CEA level cannot only predict tumour downstaging and ypTNM stage for rectal cancer following 30 Gy/10 f nRT, but also promisingly suggests a high incidence of early occurring distant metastasis. These findings may be used to select patients with nRT resistance and occult metastasis and make alternative treatment strategies.

Distal dissection in total mesorectal excision, and preoperative chemoradiotherapy and lateral lymph node dissection for rectal cancer

The local recurrence rate after total mesorectal excision (TME) appears to be markedly lower than that after conventional operations. We reviewed all relevant articles identified from the MEDLINE databases and clarified the rationale for TME. It is clear that distal intramural spread is rare. Even when present, such spread is not likely to extend beyond 2 cm. Data with attention to mesorectal cancer deposits suggest that mesorectal clearance of at least 4-5 cm distal to the tumor should be sufficient. TME should be performed for most tumors of the mid- and lower rectum. This does not mean that the gut tube needs to be divided at the same level in every case. Dissection of the distal mesorectum off the gut tube can be performed, so the distal line of division of the bowel wall can be made at a minimum of 2 cm below the tumor if such a maneuver would ensure that the sphincters are preserved. In cases with cancer in the upper third of the rectum, the mesorectum and gut tube can safely be divided 5 cm below the tumor without jeopardizing the recurrence rates. Our findings indicate that TME is an essential treatment approach for rectal cancer, and lateral lymph node dissection and preoperative chemoradiotherapy are additional therapies that should be considered for advanced rectal cancer.

Biomarkers for predicting future metastasis of human gastrointestinal tumors

The recent advances in surgery and radiation therapy have significantly improved the prognosis of patients with primary cancer, and the major challenge of cancer treatment now is metastatic disease development. The 5-year survival rate of cancer patients who have distant metastasis at diagnosis is extremely low, suggesting that prediction and early detection of metastasis would definitely improve their prognosis because suitable patient therapeutic management and treatment strategy can be provided. Cancer cells from a primary site give rise to a metastatic tumor via a number of steps which require the involvement and altered expression of many regulators. These regulators may serve as biomarkers for predicting metastasis. Over the past few years, numerous regulators have been found correlating with metastasis. In this review, we summarize the findings of a number of potential biomarkers that are involved in cadherin-catenin interaction, integrin signaling, PI3K/Akt/mTOR signaling and cancer stem cell identification in gastrointestinal cancers. We will also discuss how certain biomarkers are associated with the tumor microenvironment that favors cancer metastasis.

STAT3 inhibition sensitizes colorectal cancer to chemoradiotherapy in vitro and in vivo

Increased activity of signal transducer and activator of transcription 3 (STAT3) is common in human malignancies, including colorectal cancers (CRCs). We have recently reported that STAT3 gene expression correlates with resistance of CRC cell lines to 5-fluorouracil (5-FU)-based chemoradiotherapy (CT/RT). This is of considerable clinical importance, because a large proportion of rectal cancers are resistant to preoperative multimodal treatment. To test whether STAT3 contributes to CT/RT-resistance, we first confirmed that STAT3 protein expression correlated positively with increasing resistance. While STAT3 was not constitutively active, stimulation with interleukin-6 (IL-6) resulted in remarkably higher expression levels of phosphorylated STAT3 in CT/RT-resistant cell lines. A similar result was observed when we determined IL-6-induced expression levels of phosphorylated STAT3 following irradiation. Next, STAT3 was inhibited in SW480 and SW837 using siRNA, shRNA and the small-molecule inhibitor STATTIC. Successful silencing and inhibition of phosphorylation was confirmed using Western blot analysis and a luciferase reporter assay. RNAi-mediated silencing as well as STATTIC treatment resulted in significantly decreased clonogenic survival following exposure to 3 µM of 5-FU and irradiation in a dose-dependent manner, with dose-modifying factors of 1.3-2.5 at a surviving fraction of 0.37. Finally, STAT3 inhibition led to a profound CT/RT-sensitization in a subcutaneous xenograft model, with a significantly delayed tumor regrowth in STATTIC-treated mice compared with control animals. These results highlight a potential role of STAT3 in mediating treatment resistance and provide first proof of concept that STAT3 represents a promising novel molecular target for sensitizing resistant rectal cancers to CT/RT.

Prognostic significance of lymph node yield after long-course preoperative radiotherapy in patients with rectal cancer: a systematic review

AIM

A literature review was performed to elucidate whether long-course preoperative radiotherapy for patients with rectal cancer affects lymph node yield, and whether this influences prognosis.

METHOD

Cochrane Database, PubMed/MEDLINE, Scopus, Web of Knowledge, Embase and CINAHL databases and reference lists from published journal articles published between 1 January 1990 and 30 June 2011 were searched. Studies examining lymph node yield and prognosis were selected for review.

RESULTS

One thousand and twenty-nine articles were found, of which 11 met the inclusion criteria. None was a randomized controlled trial and all were cohort studies. Four studies showed that long-course preoperative radiotherapy reduced lymph node yield; however only one demonstrated a statistically significant survival benefit in patients with higher lymph node yields. Five-year survival was 48% in patients with fewer than and 69% in those with more than 11 lymph nodes identified in the operative specimen (P = 0.04).

CONCLUSION

Whilst long-course preoperative radiotherapy appears to reduce lymph node yield in patients with rectal cancer, no causal relationship between lymph node yield and survival can be established in this group of patients.

Carcinoembryonic antigen (CEA) level, CEA ratio, and treatment outcome of rectal cancer patients receiving pre-operative chemoradiation and surgery

Background

To investigate serum carcinoembryonic antigen (CEA) as a prognostic factor for rectal cancer patients receiving pre-operative chemoradiotherapy (CRT).

Methods

Between 2000 and 2009, 138 patients with advanced rectal cancer receiving CRT before surgery at our hospital were retrospectively classified into 3 groups: pre-CRT CEA <6 ng/ml (group L; n = 87); pre-CRT CEA ≥ 6 ng/ml and post-CRT CEA <6 ng/ml (group H-L; n = 32); and both pre- and post-CRT CEA ≥ 6 ng/ml (group H-H; n = 19). CEA ratio (defined as post-CRT CEA divided by pre-CRT CEA), post-CRT CEA level and other factors were reviewed for prediction of pathologic complete response (pCR).

Results

Five-year disease-free survival (DFS) was better in groups L (69.0%) and H-L (74.5%) than in group H-H (44.9%) (p = 0.024). Pathologic complete response was observed in 19.5%, 21.9% and 5.3% of groups L, H-L and H-H respectively (p = 0.281). Multivariate analysis showed that ypN stage and pCR were independent prognostic factors for DFS and that post-CRT CEA level was independently predictive of pCR. As a whole, post-CRT CEA <2.61 ng/ml predicted pCR (sensitivity 76.0%; specificity 58.4%). For those with pre-CRT CEA ≥6 ng/ml, post-CRT CEA and CEA ratio both predicted pCR (sensitivity 87.5%, specificity 76.7%).

Conclusions

In patients with pre-CRT serum CEA ≥6 ng/ml, those with “normalized” CEA levels after CRT may have similar DFS to those with “normal” (<6 ng/ml) pre-CRT values. Post-CRT CEA level is a predictor for pCR, especially in those with pre-CRT CEA ≥6 ng/ml.

Combined modality therapy for rectal cancer: the relative value of posttreatment versus pretreatment CEA as a prognostic marker for disease recurrence

PURPOSE

To evaluate the prognostic significance of the first postsurgery carcinoembryonic antigen (CEA) level in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiation (nCRT) and total mesorectal excision.

METHODS

A total of 100 patients underwent nCRT and had baseline and posttreatment CEA levels recorded within 6 months of surgery. The median radiotherapy dose was 50.4 Gy. Eighty-six patients received adjuvant 5-fluorouracil-based chemotherapy. Prognostic factors were analyzed for possible associations with freedom from failure (FFF) by univariate and multivariate analyses. Median follow-up was 30 months.

RESULTS

The median CEA (ng/ml) levels at baseline before nCRT, after nCRT, and after total mesorectal excision were 3.6, 1.7, and 1.3, respectively. Pathologic complete response was observed in 22%. FFF at 36 months was 78%. Local failure and distant failure occurred in 4 and 20% of the patients, respectively. On univariate analysis, pathologic complete response, margin status, and both pretreatment and postsurgery CEA levels were associated with recurrence (all P < 0.05). On multivariate analysis, pathologic complete response (P < 0.007), margin status (P < 0.001), and postsurgery CEA level (P = 0.003), but not baseline CEA level (P = 0.2), were found to be associated with recurrence.

CONCLUSIONS

After nCRT for rectal cancer, postsurgery CEA level may have more prognostic value than pretreatment level. Patients with a postsurgery CEA level of >2.5 ng/ml have higher rates of recurrence and may warrant closer surveillance.