Long-term oncologic outcome following preoperative combined modality therapy and total mesorectal excision of locally advanced rectal cancer

Novel single-nucleotide polymorphism markers predictive of pathologic response to preoperative chemoradiation therapy in rectal cancer patients

PURPOSE

Studies aimed at predicting individual responsiveness to preoperative chemoradiation therapy (CRT) are urgently needed, especially considering the risks associated with poorly responsive patients.

METHODS AND MATERIALS

A 3-step strategy for the determination of CRT sensitivity is proposed based on (1) the screening of a human genome-wide single-nucleotide polymorphism (SNP) array in correlation with histopathologic tumor regression grade (TRG); (2) clinical association analysis of 113 patients treated with preoperative CRT; and (3) a cell-based functional assay for biological validation.

RESULTS

Genome-wide screening identified 9 SNPs associated with preoperative CRT responses. Positive responses (TRG 1-3) were obtained more frequently in patients carrying the reference allele (C) of the SNP CORO2A rs1985859 than in those with the substitution allele (T) (P=.01). Downregulation of CORO2A was significantly associated with reduced early apoptosis by 27% (P=.048) and 39% (P=.023) in RKO and COLO320DM colorectal cancer cells, respectively, as determined by flow cytometry. Reduced radiosensitivity was confirmed by colony-forming assays in the 2 colorectal cancer cells (P=.034 and .015, respectively). The SNP FAM101A rs7955740 was not associated with radiosensitivity in the clinical association analysis. However, downregulation of FAM101A significantly reduced early apoptosis by 29% in RKO cells (P=.047), and it enhanced colony formation in RKO cells (P=.001) and COLO320DM cells (P=.002).

CONCLUSION

CRT-sensitive SNP markers were identified using a novel 3-step process. The candidate marker CORO2A rs1985859 and the putative marker FAM101A rs7955740 may be of value for the prediction of radiosensitivity to preoperative CRT, although further validation is needed in large cohorts.

Prognostic value of microsatellite instability in sporadic locally advanced rectal cancer following neoadjuvant radiotherapy

AIMS

This study was conducted to investigate the clinicopathological significance and prognostic value of microsatellite instability (MSI) in locally advanced rectal cancer (LARC) following neoadjuvant radiotherapy.

METHODS AND RESULTS

A total of 316 consecutive patients with LARC who underwent neoadjuvant radiotherapy and curative surgery were included retrospectively. Microsatellite instability in pretreatment biopsy tissue was assessed using the pentaplex panel of mononucleotides. Twenty-five tumours (7.9%) were assessed as high-frequency MSI (MSI-H) and 291 were low-frequency MSI (MSI-L; n = 42) or microsatellite stable (MSS; n = 249). There were no significant differences in terms of gender, age, tumour location or pretreatment serum carcinoembryonic antigen between the MSI-H and MSI-L + MSS groups. Microsatellite instability was not associated statistically with pathological stage, radiation-induced tumour regression or downstaging. No significant difference was found in disease-free survival (DFS) between the two groups but, within the subgroup of ypN0 stage, patients with MSI-H tumours presented a significantly improved DFS compared with those with MSI-L or MSS tumours (100% versus 79.8%, P < 0.05), whereas no DFS improvement was observed for patients with MSI-H tumours in the ypN + subgroup.

CONCLUSIONS

Microsatellite instability could not predict a histopathological response to neoadjuvant radiotherapy, but was a good prognostic marker for patients without lymph node metastasis after neoadjuvant radiotherapy.

Response to neoadjuvant therapy in patients with early age-of-onset rectal cancer

BACKGROUND

The incidence of rectal cancer in patients ≤ 50 years of age is increasing. The response to neoadjuvant treatment in patients ≤ 50 years of age is not known. Factors affecting the response to neoadjuvant therapy in this age group have not been evaluated.

OBJECTIVE

This study aims to evaluate the rate and identify factors that affect pathologic response to neoadjuvant therapy in patients with early age-of-onset rectal cancer.

DESIGN

This study is a retrospective review.

SETTING

The investigation was conducted at a tertiary-care cancer referral center.

PATIENTS

Included were 193 consecutive patients ≤ 50 years of age with rectal cancer who underwent neoadjuvant therapy followed by surgical resection.

INTERVENTIONS

No interventions were performed.

MAIN OUTCOME MEASURES

The primary outcome measured was the pathologic response to neoadjuvant treatment.

RESULTS

The median age was 44 years, and 34% of the patients were female. The median distance from the anal verge was 7 cm. The median percentage of lumen occupied by tumor was 50%. The median CEA level was 3.5 ng/mL. The median treatment response was 80%. The mean number of lymph nodes examined was 15 per patient. Twenty-two percent of patients had a complete or near-complete (≥ 95%) response to neoadjuvant treatment. Seventy-seven percent of evaluable patients experienced tumor or lymph node downstaging on pathologic examination. The presence of adverse histologic features, percentage of lumen occupied by tumor, and CEA level differed between those with <95% response and those with ≥ 95% response to neoadjuvant therapy, although CEA level was not significant when stage IV patients were excluded.

LIMITATIONS

This is a retrospective review with heterogeneity in workup, treatment regimens, and interval to surgery. Long-term oncologic outcomes are not available.

CONCLUSIONS

The rate of response to neoadjuvant treatment appears similar in patients with early age-of-onset rectal cancer to non-age-based cohorts in the literature. Adverse histologic features and bulky circumferential tumors may be suggestive of a decreased response to neoadjuvant therapy.

What is the incidence of metastatic lymph node involvement after significant pathologic response of primary tumor following neoadjuvant treatment for locally advanced rectal cancer?

BACKGROUND

In locally advanced rectal cancer (LARC) patients, major response to neoadjuvant radiotherapy (NR) has been associated with favorable long-term outcomes. Positive pathologic nodal status was recently proven to be associated with poor prognosis even after total regression of primary tumor (ypT0). The aim of this study was to evaluate the rate of lymph node (LN) involvement in patients with complete (ypT0) or major (TRG1: very few viable tumor cells) response.

METHODS

Included were patients with complete or major response after radiotherapy followed by surgery and histological examination of the whole specimen.

RESULTS

From 1996 to 2010, 245 patients with LARC were treated by NR. We collected clinical data for 53 patients (21.6 %) with ypT0 (n = 26, 49 %) or TRG1 (n = 27, 51 %) response. Sphincter-preserving surgery was performed in 40 patients (75 %). Overall, nine patients (16.9 %) presented LN involvement: 2 (7.7 %) in the ypT0 group and 7 (25.9 %) in the TRG1 group (NS). Patients with ypT3 tumors had significantly more invaded LN than patients with ypT1-T2 tumors (6 of 13 [46 %] vs 1 of 14 [7 %], p = .032). After median follow-up of 30 months (range, 1-160 months), 5-year disease-free and overall survivals were 88.2 and 89.0 %, respectively.

CONCLUSIONS

There was a clear cutoff between patients with ypT0-T2 (3 of 40, 7.5 %) and ypT3 (6 of 13, 46 %) concerning the incidence of metastatic LN in patients achieving pathologic complete or major response after NR. In patients with good clinical response, local full-thickness resection of the residual tumor could be a first step, followed by standard rectal resection in cases of ypT3.

Multicentre study of circumferential margin positivity and outcomes following abdominoperineal excision for rectal cancer

Background

Rectal cancer outcomes following abdominoperineal excision (APE) have been inferior to those for anterior resection, including more positive circumferential resection margins (CRMs). An erroneously conservative interpretation of APE (rather than a radical resection termed ‘extralevator’) has been proposed as the cause. In this multicentre study, factors contributing to CRM positivity were examined following APE according to its original description.

Methods

Data were collected from five hospital databases up to June 2011 including small- and larger-volume units (3 hospitals had 5 or fewer and 2 hospitals had more than 5 APE procedures per year). Primary outcome measures were CRM status; secondary outcomes were local recurrence and death.

Results

Of 327 patients, 302 patients had complete data for analysis. Some 50·0 per cent of patients had neoadjuvant chemoradiotherapy. Histopathological examination showed that 62·9 per cent had tumour category T3 or T4 cancers, 42·1 per cent had node-positive disease and the CRM positivity rate was 13·9 per cent. Multivariable analysis showed only pathological tumour category pT4 (odds ratio 19·92, 95 per cent confidence interval 6·48 to 68·61) and node positivity (odds ratio 3·04, 1·32 to 8·05) to be risk factors for a positive circumferential margin. CRM positivity was a risk factor for local recurrence (P = 0·022) and decreased overall survival (P = 0·001). Hospital volume had no impact on the likelihood of CRM positivity (P = 0·435).

Conclusion

In patients undergoing APE by appropriately trained surgeons using a standardized approach, margin positivity was dictated by tumour stage, but not by centre or surgeon.

Neoadjuvant chemoradiotherapy with or without panitumumab in patients with wild-type KRAS, locally advanced rectal cancer (LARC): a randomized, multicenter, phase II trial SAKK 41/07

BACKGROUND

We conducted a randomized, phase II, multicenter study to evaluate the anti-epidermal growth factor receptor (EGFR) mAb panitumumab (P) in combination with chemoradiotherapy (CRT) with standard-dose capecitabine as neoadjuvant treatment for wild-type KRAS locally advanced rectal cancer (LARC).

PATIENTS AND METHODS

Patients with wild-type KRAS, T3-4 and/or N+ LARC were randomly assigned to receive CRT with or without P (6 mg/kg). The primary end-point was pathological near-complete or complete tumor response (pNC/CR), defined as grade 3 (pNCR) or 4 (pCR) histological regression by Dworak classification (DC).

RESULTS

Forty of 68 patients were randomly assigned to P + CRT and 28 to CRT. pNC/CR was achieved in 21 patients (53%) treated with P + CRT [95% confidence interval (CI) 36%-69%] versus 9 patients (32%) treated with CRT alone (95% CI: 16%-52%). pCR was achieved in 4 (10%) and 5 (18%) patients, and pNCR in 17 (43%) and 4 (14%) patients. In immunohistochemical analysis, most DC 3 cells were not apoptotic. The most common grade ≥3 toxic effects in the P + CRT/CRT arm were diarrhea (10%/6%) and anastomotic leakage (15%/4%).

CONCLUSIONS

The addition of panitumumab to neoadjuvant CRT in patients with KRAS wild-type LARC resulted in a high pNC/CR rate, mostly grade 3 DC. The results of both treatment arms exceeded prespecified thresholds. The addition of panitumumab increased toxicity.

Treatment of locally advanced rectal cancer: Controversies and questions

Rectal cancers extending through the rectal wall, or involving locoregional lymph nodes (T3/4 or N1/2), have been more difficult to cure. The confines of the bony pelvis and the necessity of preserving the autonomic nerves makes surgical extirpation challenging, which accounts for the high rates of local and distant relapse in this setting. Combined multimodality treatment for rectal cancer stage II and III was recommended from National Institute of Health consensus. Neoadjuvant chemoradiation using fluoropyrimidine-based regimen prior to surgical resection has emerged as the standard of care in the United States. Optimal time of surgery after neoadjuvant treatment remained unclear and prospective randomized controlled trial is ongoing. Traditionally, 6-8 wk waiting period was commonly used. The accuracy of studies attempting to determine tumor complete response remains problematic. Currently, surgery remains the standard of care for rectal cancer patients following neoadjuvant chemoradiation, whereas observational management is still investigational. In this article, we outline trends and controversies associated with optimal pre-treatment staging, neoadjuvant therapies, surgery, and adjuvant therapy.

Evaluation of histological regression grading systems in the neoadjuvant therapy of rectal cancer: do they have prognostic impact?

PURPOSE

Neoadjuvant treatment options have been developed to improve survival of patients with locally advanced rectal cancer. As only patients with a major histopatholocial response benefit from this preoperative therapy, several tumor regression grading systems have been developed. However, currently no accepted comprehensive grading system for clinical use is available. Therefore, we studied the impact of four histological regression grading systems in the neoadjuvant therapy of rectal cancer.

METHODS

In this retrospective study, 85 patients with locally advanced rectal cancer were included. All patients received a neoadjuvant radiochemotherapy followed by surgical resection. The histological regression grading was evaluated using four classification systems: (1) grading system by the Japanese society of colorectal cancer, (2) grading system by Junker-Müller, (3) grading system by Dworak, (4) Cologne grading system. The four classification systems were analyzed for their prognostic impact.

RESULTS

The following significant correlations were detected between the four classification systems and the ypTNM categories: (1) patients with a ypT3/4 category had significantly more often a worse histopathologic response in all four grading systems (p = 0.001); (2) a ypN0 category was significantly correlated with good histopathologic response only in the Cologne grading system; (3) in the Junker-Müller and Dworak grading systems, a ypM0 category was significantly correlated with a good histopathologic response (p = 0.046; p = 0.03). However, none of the used classification systems had a prognostic impact on survival.

CONCLUSIONS

Currently, none of the analyzed histological regression grading systems is effective for clinical use.

Oncologically safe distal resection margins in rectal cancer patients treated with chemoradiotherapy

INTRODUCTION

Although current guidelines recommend distal resection margins (DRM) of 2-5 cm in rectal cancer operation, smaller margins may be safe. We therefore assessed the impact of distal margins on outcomes in patients with rectal cancer treated with neoadjuvant chemoradiotherapy (CRT) followed by radical resection or resection followed by adjuvant CRT.

MATERIALS AND METHODS

This study involved 376 patients who underwent sphincter-saving resection for rectal adenocarcinoma and pre- or postoperative CRT between 2000 and 2006. DRMs were measured on pinned fixed specimens. We excluded patients who did not complete planned CRT and those with stage IV disease. A retrospective cross-sectional analysis was performed.

RESULTS

No significant differences in local recurrence (9.8 versus 7.3%; P = 0.324) and systemic recurrence (16.4 versus 18.7%; P = 0.731) were observed in patients with DRMs of ≤5 and >5 mm, respectively. Moreover, in each DRM category, there were no differences in local and systemic recurrence rates between patients who received pre- or postoperative CRT. DRM did not affect overall survival (P = 0.880) or 5-year survival rate (80.3 versus76.8%; P = 0.340).

CONCLUSION

A distal margin of at least 5 mm with negative resection margin on frozen section does not reduce oncological safety in rectal cancer patients who receive pre- or postoperative CRT.

Significant correlation between LKB1 and LGR5 gene expression and the association with poor recurrence-free survival in rectal cancer after preoperative chemoradiotherapy

PURPOSE

The aim of the present study was to investigate whether the gene expression levels of LKB1 and LGR5 correlated with clinical outcome in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy (CRT).

METHODS

Residual cancer cells were obtained from 52 patients with locally advanced rectal cancer treated with preoperative CRT. Total RNA was then isolated from formalin-fixed, paraffin-embedded specimens using microdissection. The expression levels of LKB1 and LGR5 genes were measured using real-time reverse-transcription polymerase chain reaction and by immunohistochemistry. In addition, in vitro studies were performed using colon cancer cell lines to study the serial changes of LKB1, LGR5 and PRKAA1 (AMPK) gene expression levels after irradiation.

RESULTS

Our data demonstrate that specimens obtained from patients with poor pathological response and tumor recurrence had significantly higher gene expression levels of LKB1 and LGR5 than those without them (P < 0.05), and there was a significant positive correlation between LKB1 and LGR5 gene expression after CRT (Spearman's ρ: 0.429, P = 0.0023). The patients with high expression levels of both LKB1 and LGR5 had a significantly lower recurrence-free survival compared with the other group (P = 0.0055, 95 % confidence interval: 1.39-11.08). Lastly, in vitro studies demonstrated a similar pattern of serial gene expression among LKB1, LGR5 and PRKAA1 after irradiation.

CONCLUSIONS

Our results suggest that LKB1 and LGR5 expression may be implicated in resistance to CRT, therefore contributing to tumor relapse in patients with locally advanced rectal cancer treated with preoperative CRT.

Pulmonary recurrence predominates after combined modality therapy for rectal cancer: an original retrospective study

OBJECTIVE

To characterize patterns of recurrence in locally advanced rectal cancer treated with combined modality therapy (CMT): neoadjuvant chemoradiation + total mesorectal excision + adjuvant chemotherapy.

METHODS

A total of 593 consecutive rectal cancer patients (1998 to 2007) with locally advanced (stage II/III) disease (noted on endorectal ultrasound or magnetic resonance imaging) who received CMT were analyzed for patterns of recurrence.

RESULTS

After median 44-month follow-up (interquartile range, 25 to 64 months), 119 patients (20%) recurred: 105 distant, 7 local, 7 local and distant, and 112 distant-only recurrence. Ninety-three (78%) had single-organ recurrence, and 26 (22%) had multiple-organ recurrence. The most common site of distant recurrence was lung (69% of all patients with distant relapse); 20% had liver recurrence. Fourteen patients (2.4%) recurred locally. Pulmonary metastases were most commonly identified by computed tomographic scan versus abnormal positron emission tomographic (PET) scan or carcinoembryonic antigen (CEA). Risk factors associated with pulmonary recurrence were the following: pathologic stage, tumor distance from anal verge, lymphovascular or perineural invasion. Five-year freedom from pulmonary recurrence for patients with 0, 1, 2, or 3 risk factors was 99%, 90%, 61%, and 42%, respectively. Thirty of 59 patents with pulmonary recurrence underwent lung metastasectomy; 3-year freedom from recurrence was 37%.

CONCLUSIONS

Unlike colon cancer, which most frequently recurs in the liver, locally advanced rectal cancer treated with CMT relapses most frequently in the lung. Pulmonary metastasis was associated with advanced pathologic stage, low-lying tumor, lymphovascular invasion, or perineural invasion. Confirmation of pulmonary metastasis usually requires serial imaging because metastases are often small when initially detected, well below the resolution of PET, and not necessarily associated with elevated CEA. Individualized risk-based surveillance strategies are recommended in this patient population.

Clinical significance of LGR5 and CD44 expression in locally advanced rectal cancer after preoperative chemoradiotherapy

LGR5, known as a target of Wnt signaling, has been reported as an intestinal stem cell marker. Recent reports showed that LGR5 was associated with carcinogenesis and tumor invasion in colorectal cancer. CD44 is a ubiquitously expressed cell adhesion molecule and also a potential cell surface marker on colon cancer stem cells. Both LGR5 and CD44 have been also reported to be Wnt signal targets. The aim of this study was to investigate the association of these markers with clinical outcome in rectal cancer after preoperative chemoradiotherapy (CRT). A total of 52 rectal cancer specimens were obtained from patients who underwent preoperative CRT. We performed transcriptional and immunohistochemical analyses, and retrospectively studied the association of LGR5 and CD44 expression levels with clinical outcomes. For CD44, its expression in cancer stroma was also evaluated. The levels of cancer LGR5 and CD44 gene expression were significantly and positively correlated. LGR5 gene expression level in cancer and positivity of CD44 gene expression in cancer stroma were significantly correlated with disease recurrence. Elevated cancer LGR5 gene expression and positive CD44 gene expression in cancer stroma were significantly associated with poor recurrence-free and overall survival. Multivariate analysis indicated that positivity of stromal CD44 gene expression was an independent prognostic factor for the recurrence and overall survival of patients with rectal cancer after preoperative CRT. In conclusion, LGR5 and CD44 expression may be coordinately associated with tumor relapse in locally advanced rectal cancer after preoperative CRT.

Multimodal treatment strategies for locally advanced rectal cancer

This review outlines the important multimodal treatment issues associated with locally advanced rectal cancer. Changes to chemotherapy and radiation schema, as well as modern surgical approaches, have led to a revolution in the management of this disease but the morbidity and mortality remains high. Adequate treatment is dependent on precise preoperative staging modalities. Advances in staging via endorectal ultrasound, computed tomography, MRI and PET have improved pretreatment triage and management. Important prognostic factors and their impact for this disease are under investigation. Here we discuss the different treatment options including modern tumor-related surgical approaches, neoadjuvant as well as adjuvant therapies. Further clinical progress will largely depend on the broader implementation of multidisciplinary treatment strategies following the principles of evidence-based medicine.

T2 weighted signal intensity evolution may predict pathological complete response after treatment for rectal cancer

OBJECTIVES

To determine the diagnostic value of T2-weighted signal intensity evolution in the tumour for detection of complete response to neoadjuvant chemoradiotherapy in patients with rectal cancer.

METHODS

Thirty-nine patients diagnosed with locally advanced adenocarcinoma and treated with chemoradiotherapy (CRT), followed by surgery, underwent magnetic resonance imaging (MRI) before and after CRT on 1.5-T MRI using T2-weighted fast spin-echo (FSE) imaging. The relative T2-weighted signal intensity (rT2wSI) distribution in the tumour and post-CRT residual tissue was characterised by means of the descriptive statistical parameters, such as the mean, 95th percentile and standard deviation (SD). Receiver operating characteristic curves were used to determine the diagnostic potential of the CRT-induced alterations (Δ) in rT2wSI descriptives. The tumour regression grade (TRG) served as a histopathological reference standard.

RESULTS

CRT induced a significant decrease of approximately 50% in all rT2wSI descriptives in complete responders (TRG1). This drop was significantly larger than for incomplete response groups (TRG2-TRG4). The ΔrT2wSI descriptives produced a high diagnostic performance for identification of complete responders, e.g. Δ95th percentile, ΔSD and Δmean resulted in accuracy of 92%, 90% and 82%, respectively.

CONCLUSIONS

Quantitative assessment of the CRT-induced changes in the tumour T2-weighted signal intensity provides high diagnostic performance for selection of complete responders.

Preoperative versus postoperative radiotherapy for rectal cancer in a decision analysis and outcome prediction model

PURPOSE

Reduction of local recurrences has been achieved by radiotherapy, but also by improved surgical technique (total mesorectal excision). Radiotherapy has adverse effects and cannot exceed local dose limits. Neoadjuvant radiotherapy may result in overtreatment. We aimed to define the minimum local benefit that would have to be postulated for radiotherapy in order to bring a benefit to the overall cohort. We hypothesized that saving radiotherapy as treatment for a subset of patients with high-risk tumors and local recurrences improves the outcome of the overall cohort. We sought to simulate preoperative versus postoperative radiotherapy in theoretical decision analysis model based on published recurrence rates, with overall survival being the primary end point.

METHODS

Computerized literature search for studies published between 1996 and 2011, supplemented by manual review of the retrieved reference lists.

RESULTS

Postoperative radiotherapy evolved as preferred strategy with cure rates of 65.6 % vs. 63.7 % for postoperative and neoadjuvant radiotherapy, respectively, and a decrease of radiation exposure to 42.9 % of the cohort. The system was sensitive to (1) the fraction of stage I cancers included in the cohort, (2) the difference between local recurrence rates (LRR) for neoadjuvant radiotherapy, adjuvant radiotherapy, or surgery-only approach, and (3) the compliance with the postoperative radiotherapy. If the surgery-only recurrence was set to the published 10 %, 13 %, and 27 %, respectively, adjuvant radiotherapy had to achieve LRR below the threshold values of 6.3 %, 8.5 %, and 18.3 % to reverse the impact of compliance.

CONCLUSIONS

Radiotherapy only improves cancer-specific survival of the cohort if there is a large difference in LRR with versus without it. Routine treatment may therefore be inferior to a tailored radiotherapy regimen.

Preoperative concurrent chemoradiotherapy for locally advanced rectal cancer: treatment outcomes and analysis of prognostic factors

PURPOSE

This study was designed to investigate the long-term oncologic outcomes for locally advanced rectal cancer patients after treatment with preoperative concurrent chemoradiotherapy followed by total mesorectal excision, and to identify prognostic factors that affect survival and pathologic response.

MATERIALS AND METHODS

From June 1996 to June 2009, 135 patients with locally advanced rectal cancer were treated with preoperative concurrent chemoradiotherapy followed by total mesorectal excision at Kyung Hee University Hospital. Patient data was retrospectively collected and analyzed in order to determine the treatment outcomes and identify prognostic factors for survival.

RESULTS

The median follow-up time was 50 months (range, 4.5 to 157.8 months). After preoperative chemoradiotherapy, sphincter preservation surgery was accomplished in 67.4% of whole patients. A complete pathologic response was achieved in 16% of patients. The estimated 5- and 8-year overall survival, loco-regional recurrence-free survival, and distant metastasis-free survival rate for all patients was 82.7% and 75.7%, 76.8% and 71.9%, 67.9% and 63.3%, respectively. The estimated 5- and 8-year overall survival, loco-regional recurrence-free survival, and distant metastasis-free survival rate for pathologic complete responders was 100% and 100%, 100% and 88.9%, 95.5% and 95.5%, respectively. In the multivariate analysis, pathologic complete response was significantly associated with overall survival. The predictive factor for pathologic complete response was pretreatment clinical stage.

CONCLUSION

Preoperative chemoradiotherapy for locally advanced rectal cancer resulted in a high rate of overall survival, sphincter preservation, down-staging, and pathologic complete response. The patients achieving pathologic complete response had very favorable outcomes. Pathologic complete response was a significant prognostic factor for overall survival and the significant predictive factor for a pathologic complete response was pretreatment clinical stage.

Cytoplasmic CD133 expression is a reliable prognostic indicator of tumor regression after neoadjuvant concurrent chemoradiotherapy in patients with rectal cancer

BACKGROUND

Despite development in therapeutic strategies, such as neoadjuvant concurrent chemoradiotherapy (CCRT), the prognosis of colorectal cancer remains relatively poor. Cancer stem cells (CSC) with several characteristics can lead to therapeutic resistance. CD133 has been identified as a putative CSC marker in colorectal cancer; however, its functional role still needs elucidation. We verified the role of CD133 with emphasis on expression location and correlated the results of CD133 with clinical outcome in colorectal cancer.

METHODS

We used immunohistochemistry to investigate the expression of CD133 in samples from 157 patients with colonic adenocarcinoma and from 76 patients with rectal adenocarcinoma who received neoadjuvant CCRT. We also correlated the expression location of CD133 with the clinicopathological parameters and prognosis.

RESULTS

CD133 protein was variably overexpressed in colorectal cancer tissues and was present in three locations: apical and/or endoluminal surfaces, cytoplasm, and lumen. Cytoplasmic CD133 expression level correlated significantly with tumor local recurrence (P = 0.025) and survival of patients with colorectal cancer (P = 0.002), and correlated inversely with tumor regression grading (P = 0.021) after CCRT in patients with rectal cancer.

CONCLUSIONS

The expression of CD133 in the cytoplasm is closely associated with local recurrence and patient survival, and may provide a reliable prognostic indicator of tumor regression grading in patients with rectal cancer after CCRT. Cytoplasmic CD133 expression may also help identify the surviving cancer cells in areas with nearly total regression after CCRT.

Gene expression profiles of tumor regression grade in locally advanced rectal cancer after neoadjuvant chemoradiotherapy

Tumor regression grading (TRG) reportedly has prognostic value in rectal cancer patients after pre-operative chemoradiotherapy (CRT). The aim of this retrospective study was to differentiate gene expression profiles based on TRG in residual cancer cells after CRT. We evaluated pathological response using the criteria of four TRG systems: the Japanese Society for the Cancer of Colon and Rectum (JSCCR), Mandard, Dworak and Rödel. Total RNA was obtained using microdissection from 52 locally advanced rectal cancer specimens from patients who underwent pre-operative CRT to examine the expression levels of 20 genes [PCNA, MKI67, CDKN1A (p21Cip1), CDK2, CHEK1, PDRG1, LGR5, PROM1 (CD133), CD44, SOX2, POU5F1 (OCT4), LKB1, VEGF, EGFR, HGF, MET, HIF1, GLUT1, BAX and BCL2] using real-time quantitative RT-PCR. Gene expression was compared across the four TRG systems. LGR5 gene expression levels in CRT non-responders were significantly higher than in responders in all four grading systems. Patients with elevated PDRG1 and GLUT1 gene expression had poor pathological response in three TRG systems (JSCCR, Dworak and Rödel). MKI67 gene expression in non-responders was significantly higher than in responders in two grading systems (JSCCR and Rödel). While, BAX gene expression in responders was significantly higher than in non-responders in the Mandard TRG system. The results of this study suggest that TRG may reflect characteristics, such as proliferative activity, stemness potency and resistance to hypoxia, of residual cancer cells following pre-operative CRT.

A prospective analysis of patient outcome following treatment of T3 rectal cancer with neo-adjuvant chemoradiotherapy and transanal excision

BACKGROUND

Local excision is an alternative to anterior or abdomino-perineal resection in patients with early rectal cancer. In more advanced disease, neo-adjuvant therapy (CRXT) can result in significant disease regression such that local excision may be considered. The primary aim was to assess oncological outcome in patients with T3 rectal cancer treated with CRXT and local excision due to unsuitability for or aversion to anterior resection and stoma. The secondary aim was to examine oncological outcomes in patients treated in a similar way in the published literature.

METHODS

Between July 2006 and July 2009, patients with rectal cancer staged T3, N0/N1, M0 who were deemed unfit for or who refused anterior resection were offered long-course CRXT. Patients were restaged 8 weeks following completion. If there was a good response (regression grade 2 or 3 clinically and radiologically), full thickness transanal excision was performed. All patients were followed regularly (monthly CT abdomen/pelvis and annual endoscopy) to assess for recurrence of disease. A literature search of PubMed was performed to identify all prospective data available of T3 rectal cancers managed with CRXT and local excision.

RESULTS

Ten patients were treated over 3 years. Six patients had complete pathological response, while four patients had a partial response. The resection margins following local excision were clear in all. There was no local recurrence (median follow-up 24 months, range 9-42 months).

CONCLUSION

Neo-adjuvant chemoradiotherapy and local excision is an option in patients unfit for or averse to major surgical resection if there is a good response to CRXT.

Rectal adenocarcinoma: proposal for a model based on pretreatment prognostic factors

OBJECTIVE

Currently the choice of chemotherapy regimen in rectal cancer is made prior to surgery in contrast to colon cancer where it is made postoperatively after the pathological stage has been determined. If we could identify which are the important pretreatment prognostic factors in rectal cancer, we could then target those patients with unfavorable features to investigate potentially more effective preoperative chemotherapy regimens aimed at those with unfavorable features. The present study aimed to determine pre-treatment prognostic factors that are associated with an unfavorable outcome.

METHODS

A retrospective review of 99 rectal cancer patients operated at the Auxilio Mutuo Hospital, San Juan, Puerto Rico, and the San Pablo Hospital, Bayamón, Puerto Rico was done. Socio-demographic, clinical and treatment data were collected.

RESULTS

Of the 99 cases, 54% were males. The mean age +/- standard deviation was 62.2 +/- 10.4. In age-adjusted Cox model, male gender (HR [95%CI]: 3.32 [1.09-10.13]), mucinous carcinoma (HR [95% CI]: 3.67 [1.25-10.77]), and clinical stages II & III (HR [95%CI]: 8.19 [1.08-62.08]) were predictors of poor prognosis. In the multivariate age-adjusted analysis, a tendency towards a poorer prognosis was observed for male patients (HR: 2.60), carcinoembryonic antigen level > or =5 ng/ml (HR: 2.55), mucinous carcinoma (HR: 2.96), and clinical stages II & III (HR: 4.96), although results were not statistically significant (p > 0.05).

CONCLUSION

Although current therapeutic results are relatively favorable with preoperative 5-fluorouracil and radiotherapy, future clinical trials should address the management of those cases with adverse pretreatment prognostic factors so that they can be treated with potentially more effective albeit more toxic chemotherapy regimens.

Tumor invasion of muscular vessels predicts poor prognosis in patients with pancreatic ductal adenocarcinoma who have received neoadjuvant therapy and pancreaticoduodenectomy

Lymphovascular invasion (LVI) is a prognostic factor in many types of human malignancies, including pancreatic ductal adenocarcinoma (PDAC). However, the prognostic significance of LVI in patients with PDAC who have received neoadjuvant therapy and pancreaticoduodenectomy is unclear. In this study, we analyzed LVI in 212 patients who had received neoadjuvant chemoradiation and subsequent pancreaticoduodenectomy at our institution between January 1999 and December 2007. LVI was present in 61.8% (131/212) of the patients. Of the 131 patients who were positive for LVI, 67 (31.6%) had tumor invasion into lymphovascular spaces without muscle layer (nonmuscular lymphovascular spaces), and 64 (30.2%) had tumor invasion into muscular vessels. Tumor invasion into muscular vessels correlated with higher frequencies of positive resection margin, lymph node metastasis, and locoregional/distant recurrence. Patients with tumor invasion into muscular vessels had significantly shorter disease-free survival and overall survival than did patients who had no LVI or who had tumor invasion of nonmuscular lymphovascular spaces (P<0.01). Tumor invasion into muscular vessels is an independent prognostic factor in patients with PDAC who have received neoadjuvant therapies. Our results showed that tumor invasion into muscular vessels plays an important role in the progression of PDAC and in predicting prognosis in this group of patients.

FDG-PET assessment of rectal cancer response to neoadjuvant chemoradiotherapy is not associated with long-term prognosis: a prospective evaluation

BACKGROUND

At present there is no defined role for routine FDG-PET in the preoperative evaluation of nonmetastatic rectal cancer.

OBJECTIVE

The primary objective of this study was to evaluate the ability of FDG-PET to predict long-term prognosis based on the response to neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer.

DESIGN

This was a prospective study.

SETTINGS

This study was performed at an academic, tertiary care, comprehensive cancer center.

PATIENTS

One hundred twenty-seven patients with locally advanced rectal cancer were enrolled between September 1999 and December 2005.

INTERVENTIONS

All patients underwent FDG-PET scans before and after neoadjuvant chemoradiotherapy.

MAIN OUTCOME MEASURES

FDG-PET parameters were evaluated by at least 2 study board-certified nuclear medicine physicians, and included mean standard uptake value, maximum standard uptake value, total lesion glycolysis, and visual response score. The main outcome measures were time to recurrence and disease-specific survival.

RESULTS

Of 127 patients, 82 (65%) were men, the median age was 60 years (range, 27-82), 110 patients had stage II/III disease, and 17 patients had stage IV disease. Median follow-up among survivors was 77 months (range, 1-115 months). Nine patients had unresectable metastatic disease and were excluded from the time-to-recurrence analysis. At 5 years, 74% (95% CI = 66%-81%) of patients had not had recurrences (locally and/or distantly). The 5-year disease-specific survival was 89% (95% CI = 81%-93%). On univariate analysis, visual response score and time to recurrence came closest to having an association (HR = 0.83, 95% CI = 0.68-1.01, p = 0.06). On multivariate analysis, the visual response score was not significant (p = 0.85). No FDG-PET parameter was associated with disease-specific survival.

CONCLUSIONS

Assessment of rectal cancer response to neoadjuvant chemoradiotherapy by FDG-PET provides no prognostic information. Therefore, serial FDG-PET before and after neoadjuvant chemoradiotherapy should not be performed for this purpose.

Is step section necessary for determination of complete pathological response in rectal cancer patients treated with preoperative chemoradiotherapy?

AIMS

To assess the efficacy of the step section for determination of pathological complete response (pCR) in rectal cancer treated with preoperative chemoradiotherapy (CRT).

METHODS AND RESULTS

Of 709 patients with rectal cancer who received preoperative CRT, 88 were initially diagnosed as having pCR. These 88 patients were re-evaluated after two-level step sections of the entire tumour by using Dworak's regression grade. Additional serial step sections revealed residual tumour cells in seven of 88 patients (7.95%), all of whom were upgraded to regression grade 3 (near total regression) from regression grade 4 (total regression). Of these seven patients, one (14.3%) showed tumour recurrence, compared with 11 of 81 (13.6%) patients with a final regression grade of 4. Neither recurrence rate nor disease-free survival rate differed significantly between these two groups (P > 0.5). Calcification was significantly more frequent in grade 3 than in grade four patients (71.4% versus 32.1%; P = 0.037), and acellular mucin pools were associated with better disease-free survival (P = 0.022).

CONCLUSIONS

Stratifying patient outcome by final regression grade after step section did not yield different outcomes in patients with initial pCR. If residual tumour cells are not identified on initial meticulous examination, further processing of step sections is not necessary.

Complete pathologic response after combined modality treatment for rectal cancer and long-term survival: a meta-analysis

BACKGROUND

Complete pathologic response (CPR) after neoadjuvant chemoradiotherapy (combined modality treatment, CMT) for rectal cancer seems associated with improved survival compared to partial or no response (NPR). However, previous reports have been limited by small sample size and single-institution design.

METHODS

A systematic literature review was conducted to detect studies comparing long-term results of patients with CPR and NPR after CMT for rectal cancer. Variables were pooled only if evaluated by 3 or more studies. Study end points included rates of CPR, local recurrence (LR), distant recurrence (DR), 5-year overall survival (OS), and disease-free survival (DFS).

RESULTS

Twelve studies (1,913 patients) with rectal cancer treated with CMT were included. CPR was observed in 300 patients (15.6%). CPR and NPR patient groups were similar with respect to age, sex, tumor size, distance of tumor from the anus, and stage of disease before treatment. Median follow-up ranged from 23 to 46 months. CPR patients had lower rates of LR [0.7% vs. 2.6%; odds ratio (OR) 0.45, 95% confidence interval (CI) 0.22-0.90, P = 0.03], DR (5.3% vs. 24.1%; OR 0.15, 95% CI 0.07-0.31, P = 0.0001), and simultaneous LR + DR (0.7% vs. 4.8%; OR 0.32, 95% CI 0.13-0.79, P = 0.01). OS was 92.9% for CPR versus 73.4% for NPR (OR 3.6, 95% CI 1.84-7.22, P = 0.002), and DFS was 86.9% versus 63.9% (OR 3.53, 95% CI 1.62-7.72, P = 0.002).

CONCLUSIONS

CPR after CMT for rectal cancer is associated with improved local and distal control as well as better OS and DFS.

Perineural and intraneural invasion in posttherapy pancreaticoduodenectomy specimens predicts poor prognosis in patients with pancreatic ductal adenocarcinoma

Perineural invasion (PNI) is one of the established prognostic factors in pancreatic ductal adenocarcinoma (PDAC). However, the prognostic significance of PNI in patients with PDAC who received neoadjuvant therapy and pancreaticoduodenectomy is not clear. In this study, we performed a detailed examination of neural invasion in pancreaticoduodenectomy specimens from 212 patients with PDAC who received neoadjuvant chemoradiation (treated group) and in 60 untreated patients at our institution between January 1999 and December 2007. The frequency of PNI was higher in the untreated group (80%, 48/60) than in the treated group (58%, 123/212). For the 123 treated cases that were positive for PNI, extratumoral PNI, intratumoral PNI, intrapancreatic PNI only, extrapancreatic PNI, and intraneural invasion were identified in 86 (69.9%), 37 (30.1%), 11 (8.9%), 112 (91.1%), and 35 cases (28.5%), respectively. The presence of PNI correlated with tumor size, margin status, lymph node metastasis, pathologic tumor, and American Joint Committee on Cancer stages in the treated group. Tumor involvement of nerves >0.8 mm correlated with higher frequency of positive margin compared with tumors with PNI involving nerves ≤0.8 mm but not with other clinicopathologic parameters and survival. In the treated group, the presence of PNI or intraneural invasion correlated significantly with shorter disease-free survival and overall survival compared with no PNI or PNI only, respectively. PNI was an independent prognostic factor for both disease-free survival and overall survival in multivariate analysis. Our results showed that PNI plays an important role in the progression of PDAC and in predicting prognosis in this group of patients.

The surgical significance of residual mucosal abnormalities in rectal cancer following neoadjuvant chemoradiotherapy

BACKGROUND

Local excision of rectal cancer after neoadjuvant chemoradiotherapy (CRT) has been proposed as an alternative to radical surgery in selected patients. However, little is known about the significance of the morphological and histological features of residual tumour.

METHODS

Patients who had undergone CRT at the authors' institution between 1997 and 2010 were identified. Multiple features were assessed as putative markers of pathological response. These included: gross residual disease, diameter of residual mucosal abnormalities, tumour differentiation, presence of lymphovascular/perineural invasion and lymph node ratio.

RESULTS

Data from 220 of 276 patients were suitable for analysis. Diameter of residual mucosal abnormalities correlated strongly with pathological tumour category after CRT (ypT) (P < 0·001). Forty of 42 tumours downstaged to ypT0/1 had residual mucosal abnormalities of 2·99 cm or less after CRT. Importantly, 19 of 31 patients with a complete pathological response had evidence of a residual mucosal abnormality consistent with an incomplete clinical response. The ypT category was associated with both pathological node status after CRT (P < 0·001) and lymph node ratio (P < 0·001). Positive nodes were found in only one of 42 patients downstaged to ypT0/1. The risk of nodal metastases was associated with poor differentiation (P = 0·027) and lymphovascular invasion (P < 0·001).

CONCLUSION

In this series, the majority of patients with a complete pathological response did not have a complete clinical response. In tumours downstaged to ypT0/1 after CRT, residual mucosal abnormalities were predominantly small and had a 2 per cent risk of positive nodes, thus potentially facilitating transanal excision. The presence of adverse histological characteristics risk stratified tumours for nodal metastases.

Radiation in rectal cancer: what are the options and if/when can it be avoided?

Treatment of rectal cancer has improved greatly over recent decades. This review looks at the pivotal trials in the development of the current standard of therapy as well as new directions for more individualized therapy for rectal cancer. Rates of local recurrence and overall survival (OS) for surgery alone have improved with the use of (neo)adjuvant 5-fluorouracil (5-FU)-based chemoradiation. New surgical techniques have improved outcomes, but preoperative radiotherapy still confers an additional benefit. Despite benefits in the metastatic setting, the addition of oxaliplatin to 5-FU and radiotherapy has not shown improved outcomes, although it increased toxicity. Preoperative therapy also allows for the identification of predictive and prognostic markers for response to treatment, which has great potential to individualize treatment. Currently, the search for validated biomarkers and the refinement of risk stratification are the focus of ongoing study. Tailored therapy may include modification of the pelvic radiotherapy field, nonoperative therapy, or avoidance of radiotherapy.

Four-week neoadjuvant intensity-modulated radiation therapy with concurrent capecitabine and oxaliplatin in locally advanced rectal cancer patients: a validation phase II trial

PURPOSE

To validate tolerance and pathological complete response rate (pCR) of a 4-week preoperative course of intensity-modulated radiation therapy (IMRT) with concurrent capecitabine and oxaliplatin (CAPOX) in patients with locally advanced rectal cancer.

METHODS AND MATERIALS

Patients with T3 to T4 and/or N+ rectal cancer received preoperative IMRT (47.5 Gy in 19 fractions) with concurrent capecitabine (825 mg/m(2) b.i.d., Monday to Friday) and oxaliplatin (60 mg/m(2) on Days 1, 8, and 15). Surgery was scheduled 4 to 6 weeks after the completion of chemoradiation. Primary end points were toxicity and pathological response rate. Local control (LC), disease-free survival (DFS), and overall survival (OS) were also analyzed.

RESULTS

A total of 100 patients were evaluated. Grade 1 to 2 proctitis was observed in 73 patients (73%). Grade 3 diarrhea occurred in 9% of the patients. Grade 3 proctitis in 18% of the first 50 patients led to reduction of the dose per fraction to 47.5 Gy in 20 treatments. The rate of Grade 3 proctitis decreased to 4% thereafter (odds ratio, 0.27). A total of 99 patients underwent surgery. A pCR was observed in 13% of the patients, major response (96-100% of histological response) in 48%, and pN downstaging in 78%. An R0 resection was performed in 97% of the patients. After a median follow-up of 55 months, the LC, DFS, and OS rates were 100%, 84%, and 87%, respectively.

CONCLUSIONS

Preoperative CAPOX-IMRT therapy (47.5 Gy in 20 fractions) is feasible and safe, and produces major pathological responses in approximately 50% of patients.

Prognostic significance of glucose transporter-1 (GLUT1) gene expression in rectal cancer after preoperative chemoradiotherapy

PURPOSE

Most cancer cells exhibit increased glycolysis. The elevated glucose transporter 1 (GLUT1) expression has been reported to be associated with resistance to therapeutic agents and a poor prognosis. We wondered whether GLUT1 expression was associated with the clinical outcome in rectal cancer after preoperative chemoradiotherapy (CRT), and whether glycolysis inhibition could represent a novel anticancer treatment.

METHODS

We obtained total RNA from residual cancer cells using microdissection from a total of 52 rectal cancer specimens from patients who underwent preoperative CRT. We performed transcriptional analyzes, and studied the association of the GLUT1 gene expression levels with the clinical outcomes. In addition, we examined each proliferative response of three selected colorectal cancer cell lines to a glycolysis inhibitor, 3-bromopyruvic acid (3-BrPA), with regard to their expression of the GLUT1 gene.

RESULTS

An elevated GLUT1 gene expression was associated with a high postoperative stage, the presence of lymph node metastasis, and distant recurrence. Moreover, elevated GLUT1 gene expression independently predicted both the recurrence-free and overall survival. In the in vitro studies, we observed that 3-BrPA significantly suppressed the proliferation of colon cancer cells with high GLUT1 gene expression, compared with those with low expression.

CONCLUSION

An elevated GLUT1 expression may be a useful predictor of distant recurrence and poor prognosis in rectal cancer patients after preoperative CRT.

Securin identifies a subgroup of patients with poor outcome in rectal cancer treated with long-course (chemo)radiotherapy

BACKGROUND

Securin is an oncogene with functions in cell proliferation, tumour initiation and progression. Its prognostic value in rectal cancer is somewhat unknown. Accordingly, we studied securin expression together with Ki-67 in rectal cancer in relation to preoperative (chemo)radiotherapy (RT) and disease outcome.

MATERIAL AND METHODS

Biopsies (n = 65 for securin; n = 57 for Ki-67) and operative specimens (n = 207) from 211 patients treated with short-course RT (n = 87), long-course RT (n = 54) or surgery only (n = 70) were studied with immunohistochemistry (IHC) for securin and Ki-67 expression. In the long-course RT group, 45 patients received chemotherapy (5-fluorouracil or capecitabine) concomitantly with RT. The results of IHC were related to clinicopathological variables, disease outcome and tumour regression grade (TRG) after long-course RT.

RESULTS

Both markers showed significant reduction after RT (p < 0.001). No differences in expression was seen in the long-course RT group between the patients with or without concomitant chemotherapy (p = 0.23 for securin; p = 0.31 for Ki-67). Low Ki-67 expression, but not that of securin, in operative specimens was significantly related to excellent TRG (p = 0.02 for Ki-67; p = 0.21 for securin). In univariate survival analysis, excellent TRG predicted longer disease-specific survival (DSS; p = 0.03). In multivariate Cox analysis, high securin expression after long-course (chemo)RT was an independent predictor of shorter DSS (p = 0.036) together with patient age (p = 0.043) and disease recurrence (local or distant; p = 0.009), whereas no similar appearance was seen in other treatment groups.

CONCLUSION

Securin expression in rectal cancer is significantly reduced after RT. High securin expression and poor TRG after long-course (chemo)RT are indicators of unfavourable disease outcome.

Preoperative radiotherapy combined with capecitabine chemotherapy in Chinese patients with locally advanced rectal cancer

BACKGROUND

This phase II study is performed to evaluate the efficacy and safety of capecitabine combined with preoperative radiotherapy (RT) in Chinese patients with locally advanced rectal cancer (LARC).

METHODS

Between February 2007 and December 2008, 62 patients with LARC were treated with capecitabine (825 mg/m(2), twice daily) and concurrent RT (50.4 Gy/28 fractions). Patients underwent surgery after 6-8 weeks of combined therapy, followed by 4 cycles of adjuvant capecitabine (1,250 mg/m(2), twice daily on days 1-14, every 3 weeks). The primary endpoint was the rate of pathologic complete response (pCR).

RESULTS

Fifty-eight patients (93.5%) completed the preoperative chemoradiation course as initially planned. The most severe hematologic adverse event was leucopenia, which occurred with grade 2 intensity in 12 (19.7%) patients and grade 3 in 2 (3.3%) patients. Grade 3 diarrhea and hand-foot syndrome (HFS) were observed in one (1.6%) and two (3.3%) patients, respectively. However, no grade 4 toxicity was observed. There were no treatment-related deaths during this study. Of the 59 patients treated with surgery, all had radial margins (R0 resections). Among the 29 patients with the primary tumor ≤5 cm from the anal verge, 18 (62.1%) underwent sphincter-preserving surgical resections. pCR was found in eight patients (13.6%). The pathologic stage was lower than the initial clinical stage in 57.6% (34/59), 63.4% (26/41), and 81.4% (48/59) of the resected tumors for the primary tumor (T), lymph node (N), and combined TN categories, respectively. The estimate of disease-free survival and overall survival at 24 months were 80.6% (95% CI, 70.8-90.4%) and 92.5% (95% CI, 85.9-99.1%), respectively.

CONCLUSION

Preoperative chemoradiotherapy with capecitabine and RT appears to be a safe, well-tolerated, and effective neoadjuvant treatment modality for LARC.

Unique considerations in the patient with rectal cancer

In the past two decades, substantial progress has been made in the adjuvant management of colorectal cancer. Chemotherapy has improved overall survival in patients with node-positive (N+) disease. In contrast with colon cancer, which has a low incidence of local recurrence, patients with rectal cancer have a higher incidence requiring the addition of pelvic radiation therapy (chemoradiation). Patients with rectal cancer have a number of unique management considerations: for example, the role of short-course radiation, whether postoperative adjuvant chemotherapy is necessary for all patients, and if the type of surgery following chemoradiation should be based on the response rate. More accurate imaging techniques and/or molecular markers may help identify patients with positive pelvic nodes to reduce the chance of overtreatment with preoperative therapy. Will more effective systemic agents both improve the results of radiation as well as modify the need for pelvic radiation? This review will address these and other controversies specific to patients with rectal cancer.

Neoadjuvant treatment in rectal cancer: actual status

Neoadjuvant (preoperative) concomitant chemoradiotherapy (CRT) has become a standard treatment of locally advanced rectal adenocarcinomas. The clinical stages II (cT3-4, N0, M0) and III (cT1-4, N+, M0) according to International Union Against Cancer (IUCC) are concerned. It can reduce tumor volume and subsequently lead to an increase in complete resections (R0 resections), shows less toxicity, and improves local control rate. The aim of this review is to summarize actual approaches, main problems, and discrepancies in the treatment of locally advanced rectal adenocarcinomas.

β-catenin and Her2/neu expression in rectal cancer: association with histomorphological response to neoadjuvant therapy and prognosis

BACKGROUND

Neoadjuvant treatment strategies have been developed to improve survival of patients with advanced rectal cancer. Since mainly patients with major histopathological response benefit from this therapy, predictive and prognostic markers are needed. We examined the association of β-catenin and Her2/neu protein expression with histopathologic response to neoadjuvant radiochemotherapy and prognosis in patients with locally advanced rectal cancer.

METHODS

Fifty-four patients (33 male; 21 female; median age 60.4 years) with locally advanced rectal cancer were included in this study. All patients received a neoadjuvant radiochemotherapy (50.4 Gy, 5-FU) followed by surgical resection. Histomorphologic regression was evaluated by Dworak and Cologne staging system. Major response was defined by Dworak classification when resected specimens contained less than 50% vital tumor cells (n = 14) and by Cologne grading system when resected specimens contained less than 10% vital tumor cells (n = 15). Intratumoral β-catenin (nuclear/membranous) and Her2/neu (cytoplasmatic/membranous) expression was determined by immunohistochemistry in pre- and post-therapeutic specimens and correlated with clinicopathologic parameters.

RESULTS

A significant association was detected between pre-therapeutic membranous β-catenin levels and response: patients with a lower β-catenin protein expression showed significantly more often a major response compared with patients having high intratumoral protein levels (p = 0.011). In addition, patients with a higher Her2/neu protein expression showed a significant survival benefit compared with patients having low intratumoral protein levels (5-year survival rate: 81% vs. low 41%; p = 0.023).

CONCLUSIONS

The pre-therapeutic β-catenin and Her2/neu protein expression seem to be valuable predictive and prognostic markers in the multimodality treatment of advanced rectal cancer.

Oncologic outcomes of pathologic stage I lower rectal cancer with or without preoperative chemoradiotherapy: are they comparable?

BACKGROUND

Good responses (ypStage I) after preoperative chemoradiation therapy (CRT) and curative resection for locally advanced rectal cancer are associated with excellent local control and improved disease-free survival. This study was conducted to evaluate whether this population has comparable oncologic outcomes with those for patients with early rectal cancer (pStage I).

METHODS

This prospective study included 123 patients with pathologic stage I rectal cancer that was located less than 7 cm from the anal verge and who underwent radical resection. Of the 123 patients, 30 patients underwent preoperative CRT followed by radical resection, while 93 underwent proctectomy with no preoperative treatment. The oncologic outcomes between the 2 groups were compared.

RESULTS

The median follow-up period was 78 months. The pretreatment clinical staging was significantly different between the 2 groups (P < .001). The 10-year overall and disease-free survival rates for the patients who received preoperative CRT were 48% and 75%, respectively, which were different from the rates for those patients who did not undergo preoperative CRT (83%; P = .001 and 93%; P = .001, respectively); however, the 10-year local recurrence rates did not significantly differ between the patients who received preoperative CRT and those who did not receive preoperative CRT (7% vs 5%, respectively, P = .381).

CONCLUSION

Good responses after preoperative CRT and curative resection for locally advanced rectal cancer may be associated with local control that is similar to that of the patients with early rectal cancer.

Patterns of local recurrence in rectal cancer after a multidisciplinary approach

Improvements in surgery and the application of combined approaches to fight rectal cancer have succeeded in reducing the local recurrence (LR) rate and when there is LR it tends to appear later and less often in isolation. Moreover, a subtle change in the distribution of LRs with respect to the pelvis has been observed. In general terms, prior to total mesorectal excision the most common LRs were central types (perianastomotic and anterior) while lateral and posterior forms (presacral) have become more common since the growth in the use of combined treatments. No differences have been reported in the current pattern of LRs as a function of the type of approach used, that is, neo-adjuvant therapies (short-term or long-course radiotherapy, or chemoradiotherapy versus extended lymphadenectomy, though there is a trend towards posterior or presacral LR in patients in the Western world and lateral LR in Asia. Nevertheless, both may arise from the same mechanism. Moreover, as well as the mode of treatment, the type of LR is related to the height of the initial tumor. Nowadays most LRs are related to the advanced nature of the disease. Involvement of the circumferential radial margin and spillage of residual tumor cells from lymphatic leakage in the pelvic side wall are two plausible mechanisms for the genesis of LR. The patterns of pelvic recurrence itself (pelvic subsites) also have important implications for prognosis and are related to the potential success of salvage curative approach. The re-operability for cure and prognosis are generally better for anastomotic and anterior types than for presacral and lateral recurrences. Overall survival after LR diagnosis is lower with radio or chemoradiotherapy plus optimal surgery approaches, compared to optimal surgery alone.

A combined strategy of SAGE and quantitative PCR Provides a 13-gene signature that predicts preoperative chemoradiotherapy response and outcome in rectal cancer

PURPOSE

Preoperative chemoradiotherapy (CRT) is the treatment of choice for rectal cancer (RC), but half of the patients do not respond, suffer unnecessary toxicities, and surgery delays. We aimed to develop a model that could predict a clinically meaningful response to CRT by using formalin-fixed paraffin-embedded (FFPE) biopsies.

EXPERIMENTAL DESIGN

We first carried out an exploratory screening of candidate genes by using SAGE technology to evaluate dynamic changes in the RC transcriptome in selected refractory patients before and after CRT. Next, 53 genes (24 from SAGE and 29 from the literature) were analyzed by qPCR arrays in FFPE initial biopsies from 94 stage II/III RC patients who were preoperatively treated with CRT. Tumor response was defined by using Dworak's tumor regression grade (2-3-4 vs. 0-1). Multivariate Cox methods and stepwise algorithms were applied to generate an optimized predictor of response and outcome.

RESULTS

In the training cohort (57 patients), a 13-gene signature predicted tumor response with 86% accuracy, 87% sensitivity, and 82% specificity. In a testing cohort (37 patients), the model correctly classified 6 of 7 nonresponders, with an overall accuracy of 76%. A signature-based score identified patients with a higher risk of relapse in univariate (3-year disease-free survival 64% vs. 90%, P = 0.001) and multivariate analysis (HR = 4.35 95% CI: 1.2-15.75, P = 0.02), in which it remained the only statistically significant prognostic factor.

CONCLUSIONS

A basal 13-gene signature efficiently predicted CRT response and outcome. Multicentric validation by the GEMCAD collaborative group is currently ongoing. If confirmed, the predictor could be used to improve patient selection in RC studies.

Prognostic value of tumor response to neoadjuvant therapy in rectal carcinoma

BACKGROUND

Neoadjuvant treatment in the multimodal therapy concept of rectal carcinoma has considerable effects on prognosis appraisal.

OBJECTIVE

This study aimed to evaluate the tumor response specified as an improvement by at least one stage defined in terms of the International Union Against Cancer stages as a prognostic factor.

DESIGN

This investigation was designed as a prospective cohort study.

SETTING

This study was performed at a community-based hospital with a specialized colorectal unit.

PATIENTS

One hundred seventy-four patients with locally advanced rectal carcinoma, treated in the Dresden-Friedrichstadt hospital from 1997 to 2009, who received long-term preoperative chemoradiotherapy and underwent curative resection, were included in this study.

MAIN OUTCOME MEASURES

The main outcome measures were cause-specific and disease-free survival with respect to T and N category, International Union Against Cancer stage, venous and lymphatic invasions, grading, CEA level, complete pathologic response, tumor regression grading, International Union Against Cancer stage shift, T, N, and CEA shift, types of neoadjuvant therapy, adjuvant therapy, interval between completion of neoadjuvant chemoradiotherapy and surgery, and number of extracted lymph nodes in resected specimens. Univariate and multivariate analyses were performed.

RESULTS

Median follow-up was 45 months. One hundred twenty-one patients (69.5%) showed a response to the treatment, whereas 53 (30.5%) did not. Five-year cause-specific and disease-free survival for responders (n = 121) vs nonresponders (n = 53) were 92.6% and 73.7% vs 84.9% and 47.9%. In the univariate analysis, ypN category, venous and lymphatic invasion, tumor regression grading, International Union Against Cancer stage shift, and T and N shift were significantly predictive for cause-specific and disease-free survival. Furthermore, ypUICC stage, ypT category, grading, and complete pathologic response had an impact on disease-free survival. In the multivariate analysis, only the International Union Against Cancer stage shift kept its independent explanatory power for cause-specific P = .012, HR 3.10 (95% CI 1.28-7.51) and disease-free survival P < .001, HR 3.85 (95% CI 1.98-7.51).

LIMITATIONS

The determination of International Union Against Cancer stage shift depends on the pretreatment staging modalities.

CONCLUSION

Our investigation demonstrates that the response of tumor to neoadjuvant therapy is an independent prognostic factor in patients with rectal carcinoma.

Slug expression enhances tumor formation in a noninvasive rectal cancer model

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is a series of molecular changes allowing epithelial cancer cells to acquire properties of mesenchymal cells: increased motility, invasion, and protection from apoptosis. Transcriptional regulators such as Slug mediate EMT, working in part to repress E-cadherin transcription. We report a novel, noninvasive in vivo rectal cancer model to explore the role of Slug in colorectal cancer (CRC) tumor development.

METHODS

For the generation of DLD-1 cells overexpressing Slug (Slug DLD-1), a Slug or empty (Empty DLD-1) pCMV-3Tag-1 (kanamycin-resistant) vector was used for transfection. Cells were evaluated for Slug and E-cadherin expression, and cell migration and invasion. For the in vivo study, colon cancer cells (parental DLD-1, Slug DLD-1, empty DLD-1, and HCT-116) were submucosally injected into the posterior rectum of nude mice using endoscopic guidance. After 28 d, tumors were harvested and tissue was analyzed.

RESULTS

Slug expression in our panel of colon cancer cell lines was inversely correlated with E-cadherin expression and enhanced migration/invasion. Slug DLD-1 cells demonstrated a 21-fold increased Slug and 19-fold decreased E-cadherin expression compared with empty DLD-1. Similarly, the Slug DLD-1 cells had significantly enhanced cellular migration and invasion. In the orthotopic rectal cancer model, Slug DLD-1 cells formed rectal tumors in 9/10 (90%) of the mice (mean volume = 458 mm(3)) compared with only 1/10 (10%) with empty DLD-1 cells.

CONCLUSION

Slug mediates EMT with enhanced in vivo rectal tumor formation. Our noninvasive in vivo model enables researchers to explore the molecular consequences of altered genes in a clinically relevant rectal cancer in an effort to develop novel therapeutic approaches for patients with rectal cancer.

Time to locoregional recurrence after curative resection of rectal carcinoma is prolonged after neoadjuvant treatment: a systematic review and meta-analysis

AIM

A systematic review of the literature with meta-analysis was performed to evaluate the time to locoregional recurrence after curative resection of rectal carcinoma, assuming that this time is prolonged after neoadjuvant radiochemotherapy and/or present day surgery.

METHOD

English and German language peer-reviewed articles published between 1980 and 2007 were selected. Twenty-five of 118 studies fulfilled the defined inclusion and exclusion criteria. For some special questions, data of the Erlangen Registry of Colorectal Carcinoma (ERCRC) from 1985 to 1997 are reported.

RESULTS

After conventional surgery of rectal carcinoma, 75% (range 66-84%) of locoregional recurrence presented during the first 2 years after resection. Following the introduction of total mesorectal excision surgery and the use of neoadjuvant treatment, a general reduction of the frequency of local recurrence combined with a prolongation of the time to local recurrence was observed. In the practice of today, in particular after neoadjuvant long-course radiochemo-or radiotherapy, 24% (range 8-40%) of all local recurrences present later than 5 years after primary therapy. In contrast, such late local recurrences are observed in only 8% (range 5-9%) following primary surgery alone.

CONCLUSION

For a definite assessment of the therapeutic results regarding local control, a minimal follow up of 7-8 years either after neoadjuvant long-course radiochemo- or radiotherapy and a minimum of 5 years after surgery alone is necessary. For patients with primary surgery followed by adjuvant therapy, it is not possible to make a clear statement.

Change in glucose metabolism measured by 18F-FDG PET/CT as a predictor of histopathologic response to neoadjuvant treatment in rectal cancer

PURPOSE

In order to analyze the changes of glucose metabolism by maximum standardized uptake value (SUVmax) of 18F-FDG PET/CT in patients with rectal cancer submitted to neoadjuvant radiochemotherapy (nRCT) and to correlate SUV changes with tumor regression grade (TRG).

METHODS AND MATERIAL

Three sequential 18F-FDG PET/CT studies were performed in 31 patients with rectal cancer at the following time point: before starting the treatment (PET/CT1), during the treatment (PET/CT2), and after completion of neoadjuvant treatment (PET/CT3). The SUVmax values of the rectal lesion in the PET/CT1 (SUV1), PET/CT2 (SUV2), and PET/CT3 (SUV3) were obtained; deltaSUV1 [(SUV1 - SUV2)/SUV1] and deltaSUV2 [(SUV1 - SUV3)/SUV1] were also calculated. Metabolic parameters were compared to TRG.

RESULTS

Significant differences in pathologic responder and non-responder patients were found only for SUV2 (6.4 ± 2.9 in responder and 10.7 ± 4.8 in non-responder patients, respectively; P = 0.006) and SUV3 (3.6 ± 1.4 in responder and 6.6 ± 2.1 in non-responder patients, respectively; P = 0.0009). The best predictor for TRG response was SUV3 (threshold of 4.4) with sensitivity, specificity, accuracy, negative predictive value, and positive predictive value of 77.3%, 88.9%, 80.7%, 61.5%, and 94.4%, respectively.

CONCLUSION

18F-FDG PET/CT is a reliable and accurate technique to assess the response to nRCT in rectal cancer. In our population, the absolute value of SUVmax after treatment was the best predictor of pathological response.