Identification of aberrantly expressed miRNAs in rectal cancer

Disturbance of miRNA expression may play a key role in the initiation and progression of colorectal cancer (CRC). CRC should be viewed as a heterogeneous disease, but previous studies have only screened dysregulated miRNAs in CRC from a panel of 96, 145, 287 and 455 miRNAs, respectively. It is necessary to identify new aberrantly expressed miRNAs in rectal cancer. In this study tissue samples were derived from patients undergoing a surgical procedure to remove a portion of cancers. The expression profile of 904 miRNAs was analyzed using a miRCURY? LNA Array from 6-paired rectal cancers and normal tissues. The expression levels of 4 miRNAs were compared by real-time PCR between colon and rectal cancer, and also the expression levels of metastatic miRNAs in different stages of rectal cancer were analyzed. We found that 67 miRNA precursors are upregulated in rectal cancer (p<0.05) and 21 of those have never been reported in colorectal cancer (CRC); 39 miRNA precursors are downregulated (p<0.05) and 24 novel dysregulated miRNAs were identified in rectal cancer. miR-31, miR-126 and miR-143 are differentially expressed between colon cancer and rectal cancer. Here, we report an miRNA profile of rectal cancer, and we identified differential expression patterns of miRNAs between rectal and colon cancers. This novel information may suggest the potential roles of these miRNAs in the diagnosis of rectal cancer.     

Identification of a microRNA expression signature for chemoradiosensitivity of colorectal cancer cells,involving miRNAs-320a, -224, -132 and let7g

Background and purpose

Preoperative chemoradiotherapy (CRT) represents the standard treatment for locally advanced rectal cancer. Tumor response and progression vary considerably. MicroRNAs represent master regulators of gene expression, and may therefore contribute to this diversity.

Material and methods

Genome-wide microRNA (miRNA) profiling was performed for 12 colorectal cancer (CRC) cell lines and an individual in vitro signature of chemoradiosensitivity was established. Functional relevance of selected miRNAs was established by transfecting miRNA-mimics into SW480 and SW837 cells. The prognostic value of selected miRNAs was assessed in 128 pretherapeutic patient biopsies.

Results

Thirty-six miRNAs were identified to significantly correlate with sensitivity to CRT (Q < 0.05) including miR-320a and other miRNAs involved in the MAPK-, TGF- and Wnt-pathway. Transfection of selected miRNAs (let-7g, miR-132, miR-224, miR-320a) each induced a shift of sensitivity. High expression of let-7g was associated with a good prognosis in rectal cancer patients (P = 0.03).

Conclusions

This is the first report of a miRNA expression signature for in vitro chemoradiosensitivity of CRC cell lines. Many of the identified miRNAs have not been linked to the response to CRT and may represent potential molecular targets to sensitize resistant cancers. If further validated, let7g expression may serve as predictive biomarker.     

Complete clinical response after neoadjuvant chemoradiation for distal rectal cancer

Multimodality treatment of rectal cancer, with the combination of radiation therapy, chemotherapy, and surgery has become the preferred approach to locally advanced rectal cancer. The use of neoadjuvant chemoradiation therapy (CRT) has resulted in reduced toxicity rates, significant tumor downsizing and downstaging, better chance of sphincter preservation, and improved functional results. A proportion of patients treated with neoadjuvant CRT may ultimately develop complete clinical response. Management of these patients with complete clinical response remains controversial and approaches including radical resection, transanal local excision, and observation alone without immediate surgery have been proposed. The use of strict selection criteria of patients after neoadjuvant CRT has resulted in excellent long-term results with no oncological compromise after observation alone in patients with complete clinical response. Recurrences are detectable by clinical assessment and frequently amenable to salvage procedures.     

Intensified Total Neoadjuvant Therapy in Patients With Locally Advanced Rectal Cancer: A Phase II Trial

AimsWe assessed the efficacy and safety of total neoadjuvant therapy, including targeted agent plus FOLFOXIRI (5-fluorouracil, leucovorin, oxaliplatin and irinotecan) induction chemotherapy followed by intensified chemoradiotherapy (CRT) and surgical resection, in patients with locally advanced rectal cancer.Materials and methodsThis was a single-arm, single-centre phase II trial. Eligible patients had non-metastatic locally advanced rectal adenocarcinoma. Based on Ras-BRAF status, patients were treated with bevacizumab (mutated Ras-BRAF) or panitumumab/cetuximab (wild-type Ras-BRAF) plus FOLFOXIRI regimen followed by oxaliplatin–5-fluorouracil-based CRT and surgery. The primary end point was pathological complete response rate. Secondary end points were toxicity, compliance, tumour downstaging, complete resection, surgical complications, local and distant failures and overall survival. The sample size was planned to expect an absolute 20% improvement in pathological complete response rate over historical literature data with an α error of 0.05 and a power of 80%.ResultsBetween October 2015 and September 2019, 28 patients (median age 66 years) were enrolled. All patients had regional lymph node involvement at diagnosis. FOLFOXIRI plus bevacizumab was administered in 11 mutated Ras-BRAF patients, whereas the 17 wild-type Ras-BRAF patients received FOLFOXIRI plus panitumumab/cetuximab. Overall, total neoadjuvant therapy was well tolerated and 26 patients (92.9%) completed the programmed strategy. A complete response was achieved in nine cases (32.1%) and a nearly pathological complete response (ypT1 ypN0) in two patients (7.2%). There was no evidence of febrile neutropenia and no grade 4 adverse events were recorded. Radical resection was achieved in all cases.ConclusionFOLFOXIRI plus targeted agent-based induction chemotherapy and intensified CRT before surgery showed promising clinical activity and was well tolerated in locally advanced rectal cancer patients. This phase II trial provides a strong rationale for phase III studies.     

Accuracy of positron emission tomography/computed tomography and clinical assessment in the detection of complete rectal tumor regression after neoadjuvant chemoradiation: long-term results of a prospective trial (National Clinical Trial 00254683)

BACKGROUND:

Neoadjuvant chemoradiation (CRT) therapy may result in significant tumor regression in patients with rectal cancer. Patients who develop complete tumor regression have been managed by treatment strategies that are alternatives to standard total mesorectal excision. Therefore, assessment of tumor response with positron emission tomography/computed tomography (PET/CT) after neoadjuvant treatment may offer relevant information for the selection of patients to receive alternative treatment strategies.

METHODS:

Patients with clinical T2 (cT2) through cT4NxM0 rectal adenocarcinoma were included prospectively. Neoadjuvant therapy consisted of 54 grays of radiation and 5‐fluorouracil‐based chemotherapy. Baseline PET/CT studies were obtained before CRT followed by PET/CT studies at 6 weeks and 12 weeks after the completion of CRT. Clinical assessment was performed at 12 weeks after CRT completion. PET/CT results were compared with clinical and pathologic data.

RESULTS:

In total, 99 patients were included in the study. Twenty‐three patients were complete responders (16 had a complete clinical response, and 7 had a complete pathologic response). The PET/CT response evaluation at 12 weeks indicated that 18 patients had a complete response, and 81 patients had an incomplete response. There were 5 false‐negative and 10 false‐positive PET/CT results. PET/CT for the detection of residual cancer had 93% sensitivity, 53% specificity, a 73% negative predictive value, an 87% positive predictive value, and 85% accuracy. Clinical assessment alone resulted in an accuracy of 91%. PET/CT information may have detected misdiagnoses made by clinical assessment alone, improving overall accuracy to 96%.

CONCLUSIONS:

Assessment of tumor response at 12 weeks after CRT completion with PET/CT imaging may provide a useful additional tool with good overall accuracy for the selection of patients who may avoid unnecessary radical resection after achieving a complete clinical response. Cancer 2012;3501–3511. © 2011 American Cancer Society.     

Neoadjuvant chemotherapy in MRI-staged high-risk rectal cancer in addition to or as an alternative to preoperative chemoradiation?

Background For patients with resectable rectal cancer chemoradiation (CRT) or short-course preoperative radiotherapy (SCPRT) reduces locoregional failure, without extending disease-free survival (DFS) or overall survival (OS). Compliance to postoperative adjuvant chemotherapy is poor. Neoadjuvant chemotherapy (NACT) offers an alternative strategy. Methods A systematic computerised database search identified studies exploring NACT alone or NACT preceding/succeeding radiation. The primary outcome measure was pathological complete response (pCR). Secondary outcome measures included acute toxicity, surgical morbidity, circumferential resection margin, locoregional failure, DFS and OS. Results Four case reports, 12 phase I/II studies, 4 randomised phase II and one randomised phase III study evaluated chemotherapy before CRT. Four prospective studies reviewed chemotherapy after CRT. Three phase II studies investigated chemotherapy using FOLFOX plus bevacizumab without radiotherapy. In 24 studies of 1271 patients, pCR varied from 7% to 36%, but with no impact on metastatic disease. Conclusions NACT before CRT delivers does not compromise CRT but has not increased pCR rates, R0 resection rate, improved DFS or reduced metastases. NACT following CRT is an interesting strategy, and the utility of NACT alone could be explored compared with SCPRT or CRT in selected patients with rectal cancer where the impact of radiotherapy on DFS and OS is marginal.     

Prognostic value of Smac expression in rectal cancer patients treated with neoadjuvant therapy

The objective was to evaluate expression of second mitochondria-derived activator of caspase (Smac) expression before and after treatment in patients treated with preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer and to correlate the clinicopathological characteristics and level of Smac expression with pathologic response and outcome. Expression of biomarker was evaluated by immunohistochemistry in tumor samples from 98 patients with clinical Stage II and III rectal cancer treated with preoperative pelvic radiotherapy plus concurrent chemotherapy. All patients received a standardized total mesorectal excision procedure after a long interval of 4–6 weeks. For Smac, patients with a good response to neoadjuvant CRT tended to have higher pre-therapy levels (P = 0.007). The level of Smac expression decreased after neoadjuvant therapy (P = 0.016). High expression of Smac before CRT, and high Dworak’s tumor regression grade (TRG) were significantly associated with improved 5-year disease-free survival (P < 0.05). Pretreatment nodal status also was significantly associated with 5-year disease-free survival and 5-year local relapse-free survival (P < 0.05). Multivariate analysis confirmed that the pretreatment expression of Smac and Lymph nodal status were independent prognostic factors. Our study suggests that high expression of Smac before neoadjuvant CRT could predict good outcome in locally advanced rectal cancer patients.     

Current Views on the Interval Between Neoadjuvant Chemoradiation and Surgery for Rectal Cancer

Neoadjuvant chemoradiation (CRT) has been established as standard treatment for stage II and III rectal cancer, and delayed interval between CRT and rectal resection has emerged as appropriate treatment due to the marked benefits associated with this approach. Despite favorable findings on downstaging and pathological complete response without increasing in morbidity and mortality, no significant improvement in sphincter preservation rate and rectal cancer overall survival has been observed with the current recommended 6–8-week interval. Trials are currently underway and may provide answers regarding the optimal interval between CRT and surgical resection, but until now, the best interval between CRT and surgery remains unclear.     

Adding Three Cycles of CAPOX after Neoadjuvant Chemoradiotherapy Increases the Rates of Complete Response for Locally Advanced Rectal Cancer

Background and Objectives: the total neoadjuvant chemoradiotherapy (TNT) includes different strategies, but the most appropriate model remains uncertain. The purpose of this retrospectively study was to evaluate the safety and pathological response in the consolidation chemotherapy model. Methods: patients with cT3/T4 or TxN + M0 rectal cancer that were receiving neoadjuvant chemoradiotherapy (CRT) (50 Gy with oral capecitabine)/TNT (CRT followed by three cycles of CAPOX) during September 2017 to September 2019 in our department were included. All of the patients were recommended to receive radical surgery. Results: a total of 197 patients were included. Eighty-one patients received CRT, while one hundred and sixteen patients received TNT. Nine patients did not undergo surgery because of the distant metastases (one patient (1.2%) in CRT group, two patients (1.7%) in TNT group) or a refusal of resection (two patients in CRT group, four patients in TNT group). The pathological complete response (pCR) rate was 32.7% in TNT compared with 12.8% in CRT (p = 0.002). There was no statistically significant difference in grade 3 acute toxicities of neoadjuvant treatment and surgical complications between the two groups. Conclusions: the consolidation chemotherapy model is safe for patients with locally advanced rectal cancer and it has a high pCR rate. The long-term follow-up is necessary to be evaluated in a future prospective, randomized trial.     

Implications for selecting local excision in locally advanced rectal cancer after preoperative chemoradiation

Local excision may offer the possibility of organ preservation for the management of locally advanced rectal cancer after neoadjuvant chemoradiotherapy (CRT). However, the oncological outcomes of this strategy have been largely associated with the risk of nodal metastases. In this study, Surveillance, Epidemiology, and End Results Program (SEER)-registered rectal cancer patients, and patients from Fudan University Shanghai Cancer Center (FUSCC) after preoperative chemoradiation were combined to analyze the incidence of lymph node metastasis. The results showed that there was a high risk for residual lymph node metastasis among patients even with complete pathologic response of primary tumor after preoperative CRT (12.6–13.2%). However, in the selected group of patients with pre-CRT MRI staging cN0 rectal cancer, there was only one ypN+ case (3.3%) in ypT0–1 group. These results suggest that pre-CRT MRI staging cN0 patients achieved ypT0–1 of bowel wall tumor may be suitable for local resection.     

Differential micro-RNA expression in primary CNS and nodal diffuse large B-cell lymphomas

Most primary CNS lymphomas (PCNSL) are diffuse large B-cell lymphomas (DLBCL). However, clinical behavior and prognosis differ considerably from those for nodal DLBCL (nDLBCL), and their pathogenesis is still not fully understood. Micro-RNAs (miRNAs) have been associated with cancer development and progression. We investigated a large miRNA panel for differential expression in PCNSL and nDLBCL, to determine new mechanisms potentially involved in PCNSL pathogenesis. Using paraffin-embedded biopsy specimens from 21 HIV-negative patients with newly diagnosed PCNSL (n = 11) and nDLBCL (n= 10), we measured the expression of 365 miRNA species by quantitative real-time PCR using low-density PCR arrays. We found that 18 miRNAs were differentially expressed: median expression levels of 13 miRNAs were 2.1-13.1 times higher in PCNSL, and median expression levels of 5 miRNAs were 2.6-3.3 times higher in nDLBCL. MiRNAs upregulated in PCNSL were associated with the Myc pathway (miR-17-5p, miR-20a, miR-9), with blocking of terminal B-cell differentiation (miR-9, miR-30b/c), or with upregulation by inflammatory cytokines (miR-155). Putative tumor-suppressor miRNAs (miR-199a, miR-214, miR-193b, miR-145) were downregulated in PCNSL. There was no overlap of miRNAs dysregulated in PCNSL with those differentially expressed between immunohistologically defined germinal center B cell-like (GCB) and non-GCB types or, apart from miR-9, with miRNAs known to be overexpressed in human brain. We conclude that PCNSL exhibits a distinct pattern of miRNA expression compared with nDLBCL. This argues for the involvement of different molecular mechanisms in the pathogenesis of these two lymphoma types.     

Extracellular matrix proteins and chemoradiotherapy: alpha5beta1 integrin as a predictive marker in rectal cancer.

AIMS: To investigate the effects of extracellular matrix (ECM) protein expression on the rates of apoptosis and proliferation in rectal cancers and subsequent response to chemoradiotherapy (CRT). METHODS: The expression of fibronectin, collagen IV, laminin and the fibronectin receptor (FnR, alpha5beta1 integrin) were analysed in 32 pre-treatment rectal cancer biopsies by immunohistochemistry. ECM expression was correlated with tumour mitotic index (MI), apoptotic index (AI) and histopathological response to CRT. RESULTS: 18/32 cancers showed a poor response and 14/32 a good response (5/14 with complete pathological response) to CRT. Moderate to strong staining was seen in 22/32 cancers for fibronectin, 5/32 for collagen IV and 18/32 for laminin. Tumour FnR was related to stromal fibronectin content, and was significantly associated with CRT response; good responders having higher FnR expression compared to poor responders. No association was found between FnR expression and either MI or AI in pre-treatment biopsies, nor between MI or AI and CRT response. CONCLUSIONS: Tumour FnR expression is independent of MI and AI, and may serve as a useful marker for CRT response in rectal cancer.     

MicroRNA profiling in locally advanced esophageal cancer indicates a high potential of miR‐192 in prediction of multimodality therapy response

To identify possible predictive markers, our study aimed to characterize microRNA (miRNA) profiles of responder and nonresponder in the multimodality therapy of locally advanced esophageal cancer. Initially, a microarray‐based approach was performed including eight patients with esophageal cancer. Patients received neoadjuvant chemoradiation followed by surgical resection. Major histopathological response was defined if resected specimens contained less than 10% vital tumor cells (major/minor response: 4/4 patients). Intratumoral RNA was isolated from both, pretherapeutic tissue biopsies in addition to corresponding surgical specimens. The profile of 768 miRNAs was analyzed in 16 specimens (preneoadjuvant and postneoadjuvant therapy). Selected miRNAs were than analyzed on pretherapeutic and post‐therapeutic biopsies of 80 patients with esophageal cancer, who underwent multimodality therapy (major/minor response: 30/50 patients). Comprehensive miRNA profiling identified miRNAs in pretherapeutic biopsies that were significantly different between major/minor responders. Based on the microarray results, miR‐192, miR‐194 and miR‐622 were selected and the dysregulated miRNAs were studied on an extended series of esophageal cancer patients. The expression of miR‐192, miR‐194 and miR‐622 was significantly reduced after neoadjuvant therapy confirming the array profiling data. Importantly, the pretherapeutic intratumoral expression of miR‐192 and miR‐194 was significantly associated with the histopathologic response of esophageal squamous cell carcinoma to multimodal therapeutic treatment. Therefore, in patients with locally advanced esophageal cancer undergoing neoadjuvant chemoradiation followed by esophagectomy, miR‐192 and miR‐194 in pretherapeutic biopsies are considered as indicators of major histopathologic regression.     

The ESTRO Breur Lecture 2010: Toward a tailored patient approach in rectal cancer

The last decades have been characterized by tremendous improvements in the treatment of rectal cancer. Based on the evidence gathered in these years, the standard treatment of patients with locally advanced rectal cancer has now become preoperative chemoradiation (CRT) followed by total mesorectal excision. Although the locoregional control with this treatment regimen is quite favorable for the majority of the patients, there is still room for further improvement. For those patients with a good response to preoperative chemoradiation (CRT), extensive surgery could be avoided and replaced by minimal invasive surgery or no surgery at all. To date however, the only way to ascertain a complete remission is pathologic examination of the resection specimen. Early response prediction of the tumor to preoperative CRT is essential for further selection of patients who could be spared invasive surgery. This could be achieved by assessing molecular markers present in the tumor tissue and blood of the patients or by non invasive functional imaging before and during preoperative treatment. For those patients with a less favorable response, treatment intensification might be the way to go. This could be accomplished by dose painting on resistant tumor regions or by the addition of molecular targeted agents to the standard treatment. In this article, we review the current standard of care and the remaining challenges in the treatment of patients with locally advanced rectal cancer.     

Serum CEA as a predictor for the response to preoperative chemoradiation in rectal cancer

BACKGROUND AND OBJECTIVES: Recent data suggest that good responders to preoperative chemoradiation (CRT) have a favorable prognosis in rectal cancer patients. The aim of this study was to investigate the predictive value of serum carcinoembryonic antigen (CEA) levels for the tumor response to preoperative CRT in rectal cancer patients. METHODS: The study comprised 141 rectal adenocarcinoma patients who underwent preoperative radiotherapy with 5-fluorouracil (FU) based chemotherapy, followed by radical surgery. The staging workup was consisted of endorectal ultrasound, abdominopelvic computed tomography scan, or magnetic resonance imaging. The outcome parameters were cancer-specific survival and disease-free survival. Pre-CRT clinicopathologic features, including age, gender, location of the tumor, clinical tumor (cT) classification, clinical nodal (cN) classification, and serum CEA levels were investigated as possible predictors for the response to preoperative CRT. RESULTS: Pathologic complete or near complete responses (good responders, GR) occurred in 26 (19%) patients, while partial or no response (poor responders, PR) occurred in the remaining 115 (81%) patients. GR showed better cancer-specific survival (P = 0.028) and disease-free survival rates (P = 0.011) than PR. Univariate analysis revealed that positive cN and elevated (>5 ng/ml) pre-CRT serum CEA levels are associated with poor tumor response to preoperative CRT. Using logistic regression analysis, elevated pre-CRT serum CEA levels were the only significant predictor for the poor response to CRT (Odd ratio = 2.876, 95% confidence interval = 1.04-7.46, P = 0.041). CONCLUSIONS: Our data suggest that elevated pre-CRT serum CEA levels are associated with poor tumor response to CRT. Therefore, pre-CRT serum CEA levels provide useful information about tumor response to preoperative CRT in rectal cancer patients.     

A case of long-term survival after curative resection of advanced rectal cancer treated by pre-operative chemoradiotherapy

We report a long-term survival case of rectal cancer that was initially thought unresectable treated with chemoradiotherapy (CRT). The patient was a 50s female with advanced rectal cancer and liver metastasis. The primary tumor was expanded locally and made abscess around the rectum. We evaluated the primary lesion as unresectable, and we performed CRT after colostomy. After radiation therapy (total 60 Gy) and chemotherapy with S-1 (3 courses), the primary tumor was remarkably reduced. The liver metastasis showed a progressive growth in size but not in number. She underwent complete resection of rectal tumor and partial resection of metastatic liver tumor. Postoperative course was uneventful, and she is alive without a recurrence for 5 years after the surgery.     

Pathologic Implications of Magnetic Resonance Imaging-detected Extramural Venous Invasion of Rectal Cancer

BackgroundExtramural venous invasion (EMVI) is a poor prognostic factor in rectal cancer. Recent advances in magnetic resonance imaging (MRI) allow for the detection of EMVI before surgery. This study aimed to analyze the correlations between MRI-detected EMVI (MR-EMVI) and pathologic parameters in patients with rectal cancer.Materials and MethodsThis study retrospectively analyzed 721 patients who underwent radical resection for locally advanced rectal cancer between 2018 and 2019 at the Asan Medical center. All patients underwent an MRI before surgery. The lesions of patients who received neoadjuvant chemoradiation therapy (CRT) were evaluated by MRI before and after the neoadjuvant CRT.ResultsOf the 721 patients, 118 (16.4%) showed a positive MR-EMVI, which significantly correlated with advanced pathologic T-category and N-category, extranodal extension, poor differentiation, lymphatic invasion, venous invasion, and perineural invasion. In addition, MR-EMVI was an independent factor for predicting the pathologic nodal status (OR 3.476, 95% CI, 2.186-5.527, P < .001). Patients with a positive MR-EMVI had a sensitivity of 28.0% and specificity of 91.9% for predicting regional lymph node metastasis, whereas the MR-N category had a sensitivity of 88.7% and specificity of 30.6%. Patients whose MR-EMVI changed from positive to negative after neoadjuvant CRT had no significant differences in pathologic parameters except for lymphatic invasion with patients who were negative before and after neoadjuvant CRT.ConclusionMR-EMVI correlated with aggressive pathologic features, which indicated a poor prognosis. MR-EMVI may be a complementary imaging biomarker for predicting nodal status and evaluating tumor response to neoadjuvant CRT.