Improved overall survival among responders to preoperative chemoradiation for locally advanced rectal cancer

Not All Patients With Locally Advanced Rectal Cancer Benefit From Neoadjuvant Therapy

BACKGROUND

While neoadjuvant combined modality therapy (NA-CMT) is beneficial for most patients with locally advanced rectal cancer some patients may experience disease progression during treatment. The purpose of this study is to identify characteristics associated with progression during NA-CMT.

METHODS

A single institution retrospective review of patients with stage II-III rectal cancer receiving NA-CMT was conducted from 2008-2019. Patients with incomplete or unknown NA-CMT treatment and those who received chemotherapy in addition to NA-CMT were excluded. Initial staging MRI was compared to post-operative pathology to determine progression. Definitions: responders (complete response or regression) and non-responders (stable disease or progression).

RESULTS

156 patients were included: 25 (16.1%) complete responders, 79 (50.6%) had evidence of regression, 34 (21.8%) were stable non-responders, and 18 (11.5%) were progressors. Those who progressed had worse overall survival. Factors associated with non-responders included black race (OR 4.5, 95% CI: 1.10-18.7) and increasing distance from the anal verge (OR 1.2, 95% CI: .2-2.9). Distance from the anal verge was determined via MRI. Recurrence was significantly more common among non-responders (15, 30.61%) when compared to responders (14, 13.46%), P = .012.

CONCLUSION

Patients who progress despite NA-CMT have overall worse survival compared to patients who do respond. While this study failed to identify modifiable or predictive risk factors for progression, the multivariate logistic regression model suggests that race and tumor biology may play a role in progression. Future studies should focus on early identification of patients who may not benefit from NA-CMT in an effort to develop alternative treatment algorithms.

Significance of Wnt/β-Catenin Signal Activation for Resistance to Neoadjuvant Chemoradiotherapy in Rectal Cancer

Although a therapeutic response to neoadjuvant chemoradiotherapy (NACRT) is important to improve oncological outcomes after surgery in patients with locally advanced rectal cancer, there is no reliable predictor for this. The Wnt/β-catenin signal is known to be crucial for the tumorigenesis of colorectal cancer. This study aimed to investigate the association of Wnt/β-catenin signal activation with a pathological response to NACRT. The immunohistochemical expression of nuclear and membranous β-catenin was analyzed in biopsy samples obtained from 60 patients with locally advanced rectal cancer who received curative surgery following NACRT. The association of Wnt/β-catenin signal activation with their clinical outcomes was investigated. Notably, the body mass index of these patients was significantly higher in the low nuclear β-catenin expression group. Moreover, patients in the high nuclear β-catenin expression group tended to have more advanced disease and a higher rate of positive vascular invasion than those in the low expression group. Furthermore, the rate of good histological responses was significantly higher in the low nuclear β-catenin expression group (72% vs. 37.1%, p < 0.01). Overall, relapse-free survival tended to be better in patients with low nuclear/high membranous β-catenin expression (n = 9) than in other individuals (n = 51) (p = 0.093 and p = 0.214, respectively). Activation of the Wnt/β-catenin signal pathway represented by nuclear β-catenin accumulation was significantly associated with a poor response to NACRT in patients with rectal cancer. Analysis of nuclear β-catenin accumulation before starting treatment might help predict the therapeutic response to NACRT.

Applying a neoscore in locally advanced rectal cancer is beneficial in predicting local recurrences after surgery

BACKGROUND AND AIM

The current study was undertaken to provide more detailed prognostic models for early prediction of local recurrences and local recurrence free survival (RFS) using different radiologic and pathologic features of locally advanced rectal carcinomas treated with neoadjuvant chemoradiation (CRT).

METHODS

One hundred patients with locally advanced rectal carcinomas decided to receive neoadjuvant CRT were retrospectively recruited, Hazard ratios (HR) were determined in the two cox regression models and only significant ratios were considered for pointing, Models were built to determine their important effects of different predictors including: pathologic T (T), pathologic N (N), grade (G), clinical stage (cTNM), site (S), perineural invasion (PNI), and response to CRT (R) on 3-year RFS, goodness of performance of each model was measured by Harrell's C index.

RESULTS

HR of 1st group of models: T+N, T+N+G, T+N+G+S, T+N+G+S+PNI, and T+N+G+S+PNI+R were summated and categorized into scores, these scores were significantly correlated with the risk of recurrence (Somer's D = 0.5, p<0.0001) & Harrell's C index = 0.751, (Somer's D = 0.6, p<0.0001) & its Harrell's C index = 0.794, (Somer's D = 0.7, p<0.0001) & C index = 0.826, Somer's D = 0.7, p<0.0001) & C index = 0.827, and (Somer's D = 0.7, p<0.0001) & C index = 0.843 respectively. The 2nd group of models including: cTNM stage, cTNM+G, cTNM+G+S, cTNM+G+S+PNI, cTNM+G+S+PNI+R scores which were significantly correlated with the HR of LRR (Somer's D = 0.2, 0.5, 0.6, 0.6, & 0.6 respectively), (p = 0.006, <0.0001, <0.0001, <0.0001, <0.0001 respectively), the corresponding Harrell's C indices were 0.595, 0.743, 0.782, 0.795, & 0.813 respectively.

CONCLUSION

We propose that the addition of biologic factors to staging of rectal cancer provide precise stratification and association with local recurrences in patients received preoperative CRT.

Nomogram to predict disease recurrence in patients with locally advanced rectal cancer undergoing rectal surgery after neoadjuvant therapy: retrospective cohort study

INTRODUCTION

Prognostic models can be used for predicting survival outcomes and guiding patient management. TNM staging alone is insufficient for predicting recurrence after chemoradiotherapy (CRT) and surgery for locally advanced rectal cancer. This study aimed to develop a nomogram to better predict cancer recurrence after CRT followed by total mesorectal excision (TME) and tailor postoperative management and follow-up.

MATERIALS AND METHODS

Between 2002 and 2019, data were retrospectively collected on patients with rectal adenocarcinoma. Data on sex, age, carcinoembryonic antigen (CEA) level, tumour location, induction chemotherapy, adjuvant chemotherapy, tumour downsizing, perineural invasion, lymphovascular invasion, pathological stage, resection margins (R0 versus R1), and pelvic septic complications were analysed. The variables significantly associated with cancer recurrence were used to build a nomogram that was validated in both the training and validation cohorts. Model performance was evaluated by receiver operating characteristic curve and area under the curve (AUC) analyses.

RESULTS

After applying exclusion criteria, 634 patients with rectal adenocarcinoma were included in this study. Eight factors (CEA level, adjuvant chemotherapy, tumour downsizing, perineural invasion, lymphovascular invasion, pathological stage, resection margins (R0 versus R1), and pelvic septic complications) were identified as nomogram variables. Our nomogram showed good performance with an AUC of 0.74 and 0.75 in the training and validation cohorts respectively.

CONCLUSION

Our nomogram is a simple tool for predicting cancer recurrence in patients with locally advanced rectal cancer after neoadjuvant CRT followed by TME. It provides an individual risk prediction of recurrence to tailor surveillance.

Adjuvant chemotherapy after neoadjuvant chemoradiation and proctectomy improves survival irrespective of pathologic response in rectal adenocarcinoma: a population-based cohort study

BACKGROUND

This study sought to determine whether adjuvant chemotherapy (AC) compared to no AC (noAC) after neoadjuvant chemoradiation (CRT) and resection for rectal adenocarcinoma prolongs survival. Current guidelines from expert groups are conflicting, and data to support administering AC to patients who received neoadjuvant CRT are lacking.

METHODS

A total of 19,867 patients met inclusion/exclusion criteria. Mean age was 58.6 ± 12.0 years, and 12,396 (62.4%) were males. Complete response (CR) was documented in 3801 (19.1%) patients and 8167 (41.1%) received AC. The cohort was stratified into pathological complete (pCR, N = 3801) and incomplete (pIR, N = 16,066) subgroups, and pIR further subcategorized into ypN0 (N = 10,191) and ypN + (N = 5875) subgroups. After propensity score matching, AC was associated with improved OS in the pCR subgroups (mean 139.1 ± 1.9 vs. 134.0 ± 2.2 months; p < 0.001), in pIR ypN0 subgroup (141.6 ± 1.5 vs. 129.9 ± 1.2 months, p < 0.001), and in pIR ypN + subgroup (155.9 ± 5.4 vs. 126.5 ± 7.6 months; p < 0.001).

RESULTS

AC was associated with improved OS in patients who received neoadjuvant CRT followed by proctectomy for clinical stages II and III rectal adenocarcinoma. This effect persisted irrespective of pathological response status.

CONCLUSIONS

AC following neoadjuvant CRT and surgery is associated with improved OS in patients with rectal adenocarcinoma. These findings warrant adoption of AC after neoadjuvant CRT and surgery for clinical stage II and III rectal adenocarcinoma.

Validation of the standardized index of shape tool to analyze DCE-MRI data in the assessment of neo-adjuvant therapy in locally advanced rectal cancer

PURPOSE

Standardized index of shape (SIS) tool validation to examine dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) in preoperative chemo-radiation therapy (pCRT) assessment of locally advanced rectal cancer (LARC) in order to guide the surgeon versus more or less conservative treatment.

MATERIALS AND METHODS

A total of 194 patients (January 2008-November 2020), with III-IV locally advanced rectal cancer and subjected to pCRT were included. Three expert radiologists performed DCE-MRI analysis using SIS tool. Degree of absolute agreement among measurements, degree of consistency among measurements, degree of reliability and level of variability were calculated. Patients with a pathological tumour regression grade (TRG) 1 or 2 were classified as major responders (complete responders have TRG 1).

RESULTS

Good significant correlation was obtained between SIS measurements (range 0.97-0.99). The degree of absolute agreement ranges from 0.93 to 0.99, the degree of consistency from 0.81 to 0.9 and the reliability from 0.98 to 1.00 (p value <  < 0.001). The variability coefficient ranges from 3.5% to 26%. SIS value obtained to discriminate responders by non-responders a sensitivity of 95.9%, a specificity of 84.7% and an accuracy of 91.8% while to detect complete responders, a sensitivity of 99.2%, a specificity of 63.9% and an accuracy of 86.1%.

CONCLUSION

SIS tool is suitable to assess pCRT response both to identify major responders and complete responders in order to guide the surgeon versus more or less conservative treatment.

Response to neoadjuvant treatment among rectal cancer patients in a population-based cohort

BACKGROUND

In rectal cancer, prediction of tumor response and pathological complete response (pCR) to neoadjuvant treatment could contribute to refine selection of patients who might benefit from a delayed- or no-surgery approach. The aim of this study was to explore the association of clinical and molecular characteristics of rectal cancer with response to neoadjuvant treatment and to compare patient survival according to level of response.

METHODS

Resected rectal cancer patients were selected from a population-based cohort study. Molecular tumor markers were determined from the surgical specimen. Tumor response and pCR were defined as downstaging in T or N stage and absence of tumor cells upon pathological examination, respectively. The associations of patient and tumor characteristics with tumor response and pCR were explored, and patient survival was determined by degree of response to neoadjuvant treatment.

RESULTS

Among 1536 patients with rectal cancer, 602 (39%) received neoadjuvant treatment. Fifty-five (9%) patients presented pCR, and 239 (49%) and 250 (53%) patients showed downstaging of the T and N stages, respectively. No statistically significant associations were observed between patient or tumor characteristics and tumor response or pCR. Patients who presented any type of response to neoadjuvant treatment had significantly better cancer-specific and overall survival compared with non-responders.

CONCLUSION

In this study, patient characteristics were not associated with response to neoadjuvant treatment, and molecular characteristics determined after surgical resection of the tumor were not predictive of pCR or tumor downstaging. Future studies should include molecular biomarkers from biopsy samples before neoadjuvant treatment.

Ten-year survival after pathologic complete response in rectal adenocarcinoma

BACKGROUND

Multimodal treatment is the standard of care for rectal adenocarcinoma, with a subset of patients achieving a pathologic complete response (pCR). While pCR is associated with improved overall survival (OS), long-term data on patients with pCR is limited.

METHODS

This is a single institution retrospective cohort study of all patients with clinical stages II/III rectal adenocarcinoma who underwent neoadjuvant chemoradiation therapy and operative resection (January 1, 2004-December 31, 2017). PCR was defined as no tumor identified in the rectum or associated lymph nodes by final pathology.

RESULTS

Of 370 patients in this cohort, 50 had a pCR (13.5%). For pCR patients, 5-year disease-free survival (DFS) was 92%, 5-year OS was 95%. Twenty-six patients had surgery > 10 years before the study end date, of which 20 had an OS > 10 years (77%) with median OS 12.1 years and 95% alive to date (19/20). Of the 50 pCR patients, there was a single recurrence in the lung at 44.3 months after proctectomy which was surgically resected.

CONCLUSION

For patients with rectal adenocarcinoma that undergo neoadjuvant chemoradiation and surgical resection, pCR is associated with excellent long-term DFS and OS. Many patients live greater than 10 years with no evidence of disease recurrence.

The impact of tumor regression grade on long-term survival in locally advanced rectal cancer treated with preoperative chemoradiotherapy

PURPOSE

The aim of this study is to investigate the prognostic effect of tumor regression grade (TRG) on long-term survival in locally advanced rectal cancer treated with preoperative chemoradiotherapy.

METHODS

Medical records of 182 patients with locally advanced rectal cancer, who were treated with preoperative chemoradiotherapy followed by surgery between 2002 and 2016, were retrospectively reviewed. TRG was classified into five categories based on the pathological response as follows - TRG1: no viable cancer cell, TRG2: single cancer cell or small groups of cancer cells, TRG3: residual tumor outgrown by fibrosis, TRG4: residual tumor outgrowing fibrosis, TRG5: diffuse residual tumor without regression. TRG1, (TRG2+TRG3), and (TRG4+TRG5) were grouped as complete response, intermediate response, and no response, respectively.

RESULTS

Of the 182 patients with locally advanced rectal cancer, 112 (61.5%) were male. The mean age was 54.4 (range, 25-87) years. The total number of patients in complete response, intermediate response, and no response group was 24 (13.2%), 105 (57.7%), and 53 (29.1%), respectively. The corresponding five-year relapse-free survival and overall survival rates were 79.8%-92.3%, 74.7%-79.4%, and 55.7%-55.8%, respectively (p < 0.05 for relapse-free survival, p < 0.05 for overall survival). According to ypTNM stage, there was no significant difference in relapse-free survival among TRG groups in ypStage I and II patients (p > 0.05). In ypStage III patients, relapse-free survival was 62 months in no response group vs. not reached in intermediate response group (p < 0.05). According to the ypTNM, there was no significant difference in overall survival among TRG groups in ypStage I, II, and III patients (p > 0.05). In the multivariate analysis, pathological complete response was found to be an independent variable for relapse-free survival and overall survival (hazard ratio (95% confidence interval), 0.34 (0.17-6.77), 0.39 (0.18-0.83), respectively).

CONCLUSION

This study showed that patients with pathological complete response to preoperative chemoradiotherapy had longer relapse-free survival and overall survival rates than those with residual disease.

Tumor volume and sphericity as predictors of local control after stereotactic radiosurgery for limited number (1-4) brain metastases from nonsmall cell lung cancer

AIM

This study aims to evaluate the usage of brain metastases (BM) tumor volume and sphericity as prognostic factors in local control (LC) after stereotactic radiosurgery (SRS) for limited number (1-4) BM from nonsmall cell lung cancer (NSCLC).

METHODS

We retrospectively reviewed 80 patients, with 141 BM, who were treated with SRS from 2012 to 2017. Local failure was defined as an increase in lesion size after SRS. LC and overall survival (OS) were estimated using Kaplan-Meier method. The Cox proportional hazards model was used for univariate and multivariate analysis.

RESULTS

The median clinical and radiographic follow-up was 11.2 and 9.0 months, respectively. The median BM tumor volume was 0.31 cm³ (0.01-21.64 cm³ ) and the median tumor sphericity was 0.76 (0.39-0.95). The median LC of the entire cohort was 28.8 months. LC rate at last follow-up was achieved in 84.4% of patients (35.5% CR, 35.5% PR, and 13.5% SD). LC was 83.8% at 1 year and 56.3% at 2 years. On multivariate analysis, only sphericity (P < .001) and volume (P = .004) were found to be a strong predictor for LC. The median OS of the entire cohort was 24.1 months. On multivariate analysis, only GPA score was found to be a predictor for OS.

CONCLUSION

BM tumor sphericity and volume were found to be strong predictors for LC. Tumor sphericity and volume should be taken into consideration when treating patients with BM and when designing future prospective studies and developing prognostic indices.

Radiation therapy for rectal cancer

Radiotherapy (RT) has remained an important pillar in the multi-modality management of rectal cancer. Adjuvant RT with concurrent chemotherapy (chemo-RT) was once the standard of care for locally advanced rectal cancer, but with time, that has now changed and neoadjuvant chemo-RT followed by total mesorectal excision (TME) surgery is the new standard. Alternatively, neoadjuvant RT alone remains an option and clinicians are tasked to choose between the two. In an era of personalised oncological management, it is unsurprising that the treatment for rectal cancer is following suit and upcoming trials are studying ways to improve outcomes and minimise toxicity for patients while tailoring treatments specific to each patient's tumour. We review the evolution of the role of RT in rectal cancer and look forward to what the future holds.

Improved survival with adjuvant chemotherapy in locally advanced rectal cancer patients treated with preoperative chemoradiation regardless of pathologic response

OBJECTIVE

The aim of this study is to examine the effect of postoperative chemotherapy on survival in patients with stage II or III rectal adenocarcinoma who undergo neoadjuvant chemoradiation (CRT) and surgical resection.

METHODS

A retrospective review of the National Cancer Database (NCDB) from 2006 to 2013 was performed. Cases were analyzed based on pathologic complete response (pCR) status and use of adjuvant therapy. The Kaplan-Meier method was used to estimate overall survival probabilities.

RESULTS

23,045 cases were identified, of which 5832 (25.31%) achieved pCR. In the pCR group, 1513 (25.9%) received adjuvant chemotherapy, and in the non-pCR group, 5966 (34.7%) received adjuvant therapy. In the pCR group, five-year survival probability was 87% (95% CI 84%-89%) with adjuvant therapy and 81% (95% CI 79%-82%) without adjuvant therapy. In the non-pCR group, five-year survival probability was 78% (95% CI 76%-79%) with adjuvant therapy and 70% (95% CI 69%-71%) without adjuvant therapy. In the non-pCR and node-negative subgroup (ypN-), five-year survival probability was 86% (95% CI 84%-88%) with adjuvant therapy and 76% (95% CI 74%-77%) without adjuvant therapy. In the non-pCR and node-positive subgroup (ypN+), five-year survival probability was 67% (95% CI 65%-70%) with adjuvant therapy and 60% (95% CI 58%-63%) without adjuvant therapy.

CONCLUSIONS

Adjuvant chemotherapy in stage II or III rectal adenocarcinoma is associated with increased five-year survival probability regardless of pCR status. We observed similar survival outcomes among non-pCR ypN- treated with adjuvant chemotherapy compared with patients achieving pCR treated with adjuvant chemotherapy.

Volumetric imaging parameters are significant for predicting the pathological complete response of preoperative concurrent chemoradiotherapy in local advanced rectal cancer

Preoperative concurrent chemoradiotherapy (CCRT) as the standard treatment for locally advanced rectal cancer (LARC) has been widely used in clinic. Its efficiency influences the prognosis and the selection of subsequent treatment. The current criteria for evaluating the prognosis of patients with extremely sensitive preoperative CCRT include the clinical complete remission response (cCR) and pathological complete response (pCR), but those with cCR may not necessarily achieve pCR, and the pCR can be confirmed only after surgery. Some scholars believe that patients with pCR after CCRT can be categorized as 'watch and wait'. Therefore, it is extremely important to find a way to predict the pCR status of patients before therapy. In this study, we examined the expression of stem cell markers and obtained direct and derivative volumetric imaging parameters before treatment. Subsequently, these factors and the general clinical data were adopted into a regression model, and the correlation between them and the pCR was analyzed. We found that the pCR of LARC was positively correlated with tumor compactness (TC), whereas it was negatively correlated with approximate tumor volume (ATV), real tumor volume (RTV), total surface area of the tumor (TSA) and tumor maximum longitudinal length (TML). In these meaningful predictors, the positive predictive values and the negative predictive values of TC were 74.73% and 94.61%, respectively. Compared with other possible predictors, TC is the most encouraging predictor of pCR. Our findings provide a way for clinicians to predict the sensitivity of preoperative CCRT and will help to select individualized treatment options for LARC patients.

Association of Adjuvant Chemotherapy With Overall Survival in Patients With Rectal Cancer and Pathologic Complete Response Following Neoadjuvant Chemotherapy and Resection

Importance

Adjuvant chemotherapy (AC) in patients with rectal cancer with pathologic complete response following neoadjuvant chemoradiotherapy (nCRT) and resection is recommended by treatment guidelines. However, its role in this setting is equivocal because data supporting benefits are lacking.

Objective

To compare the overall survival (OS) between AC and postoperative observation (OB) in patients with rectal cancer with pathologic complete response following nCRT and resection.

Design, Setting, and Participants

We identified a cohort of patients with rectal cancer and a complete pathological response (ypT0N0) after nCRT in the National Cancer Database between 2006 and 2012. Patients who received AC were compared with OB patients by propensity score matching. Overall survival was compared using the stratified log-rank test and stratified Cox regression model. The outcomes after AC vs OB were also evaluated in patient subgroups. The data analysis was completed in June 2017.

Exposures

Adjuvant chemotherapy and OB.

Main Outcomes and Measures

Overall survival.

Results

We identified 2764 patients (mean [SD] age, 60.0 [12.3] years; 40% female) with clinical stage II or III resected adenocarcinoma of the rectum who had received nCRT and were complete responders (ypT0N0M0). Of this cohort, 741 patients in the AC group were matched by propensity score to 741 patients who underwent OB. The AC cohort had better OS compared with the OB cohort (hazard ratio, 0.50; 95% CI, 0.32-0.79). The 1-, 3-, and 5-year OS rates were 99.7%, 97.1%, and 94.7% for the AC group and 99.2%, 93.6%, and 88.4% for the OB group (P = .005). In subgroup analysis, patients with clinical stage T3/T4 and node-positive disease benefited most from AC (hazard ratio, 0.47; 95% CI, 0.25-0.91).

Conclusions and Relevance

Adjuvant chemotherapy was associated with improved OS in patients with pathologic complete response after nCRT for resected locally advanced rectal cancer. This study supports the use of AC in this setting where there is currently paucity of data.

Adjuvant chemotherapy in rectal cancer patients who achieved a pathological complete response after preoperative chemoradiotherapy: a systematic review and meta-analysis

This study evaluated the prognostic impact of ACT in patients who achieved a pathological complete response (pCR). Articles published from January 1990 to September 2018 were searched in EMBASE, PubMed, Ovid, Web of Science, and Cochrane Library. Hazard ratios (HRs) and 95% confidence intervals (CIs) of overall survival (OS) were extracted. Thirteen observational studies were included. There were four National Cancer Database studies with overlapping study periods, thus individual pooled analyses of four different datasets were conducted (n = 3,182, 3,330, 3,575, and 4,739 for pooled analysis sets including Dossa et al., Polanco et al., Xu et al., and Shahab et al., respectively). Although a trend toward improved OS with ACT was observed, statistical significance was not proven (P = 0.09, P = 0.03, P = 0.12, and P = 0.10, respectively). When we performed a stratified analysis comparing the results from single institution and multicenter studies, there was no significant prognostic benefit of ACT. Publication bias was not observed. Routine use of ACT in patients with a pCR could not be warranted from the present meta-analysis. Further study of individual patient data from randomized trials is needed to clarify the role of ACT.

CT-guided cryoablation for unresectable pelvic recurrent colorectal cancer: a retrospective study

Objective

The study aimed to investigate the efficacy of computed tomography (CT)-guided cryoablation debulking of unresectable pelvic recurrent colorectal cancer (CRC).

Patients and methods

From January 2013 to April 2016, 30 patients (18 males and 12 females; aged 57.8±10.5 years) with unresectable pelvic recurrent CRC who had previously received radiotherapy or chemotherapy were included. A total of 35 tumors ranging from 1.2 to 6.3 cm underwent cryoablation. Tumor response was evaluated 1 month after cryoablation according to the Modified Response Evaluation Criteria in Solid Tumors. Logistic regression was used to analyze the risk factors for tumor response. Degree of pain palliation was also determined using the Numerical Rating Scale. Cox proportional hazard models were used to identify predictors of outcomes.

Results

Cryoablation was successfully performed in all patients. Complete response (CR) was achieved for 27 tumors in 23 patients and partial response was achieved for eight tumors in seven patients 1 month after cryoablation. The rate of CR was 77.14%, and tumor size was an independent risk factor for CR. Pain relief was satisfactory in 21 symptomatic patients (P<0.001), and the median duration of pain relief was 6.0 months (95% CI: 2.67–9.33). Serum carcinoembryonic antigen (CEA) was significantly decreased after cryoablation in 15 patients with elevated CEA (P=0.005). The median progression-free survival (PFS) was 10.0 months (95% CI: 4.43–15.67). Multivariate analysis revealed that tumor size (HR =3.089, P<0.001), sex (HR =0.089, P=0.002), and elevated CEA (HR =7.015, P=0.002) were independent predictors of PFS.

Conclusion

CT-guided cryoablation is a safe and effective therapeutic option for pelvic recurrent CRC. Tumor size is an important predictor of poor outcomes.

Assessing response to neo-adjuvant therapy in locally advanced rectal cancer using Intra-voxel Incoherent Motion modelling by DWI data and Standardized Index of Shape from DCE-MRI

Background:

Our aim was to investigate preoperative chemoradiation therapy (pCRT) response in locally advanced rectal cancer (LARC) comparing standardized index of shape (SIS) obtained from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with intravoxel-incoherent-motion-modelling-derived parameters by diffusion-weighted imaging (DWI).

Materials and methods:

Eighty-eight patients with LARC were subjected to MRI before and after pCRT. Apparent diffusion coefficient (ADC), tissue diffusion (D_t), pseudodiffusion (D_p) and perfusion fraction (f) were calculated and percentage changes ∆ADC, ∆D_t, ∆D_p, ∆f were computed. SIS was derived comparing DCE-MRI pre- and post-pCRT. Nonparametric tests and receiver operating characteristic (ROC) curves were performed.

Results:

A total of 52 patients were classified as responders (tumour regression grade; TRG ⩽ 2) and 36 as not-responders (TRG > 3). Mann–Whitney U test showed statistically significant differences in SIS, ∆ADC and ∆D_t between responders and not-responders and between complete responders (19 patients with TRG = 1) versus incomplete responders. The best parameters to discriminate responders by nonresponders were SIS and ∆ADC, with an accuracy of 91% and 82% (cutoffs of −5.2% and 18.7%, respectively); the best parameters to detect pathological complete responders were SIS, ∆f and ∆D_p with an accuracy of 78% (cutoffs of 38.5%, 60.0% and 83.0%, respectively). No increase of performance was observed by combining linearly each possible couple of parameters or combining all parameters.

Conclusion:

SIS allows assessment of preoperative treatment response with high accuracy guiding the surgeon versus more or less conservative treatment. DWI-derived parameters reached less accuracy compared with SIS and combining linearly DCE- and DWI-derived parameters; no increase of accuracy was obtained.

Dose Escalation with Simultaneous Integrated Boost (SIB) Using Volumetric Modulated Arc Therapy (VMAT) in Rectal Cancer

PURPOSE

Assess feasibility-rate of PCR, short-term toxicity after neoadjuvant concurrent chemoradiation (NACRT) delivered via simultaneous integrated boost (SIB) using volumetric modulated arc therapy (VMAT) technique for locally advanced rectal cancer.

METHODS

Retrospective evaluation of patients with locally advanced rectal cancer treated with VMAT-SIB technique preoperatively at an academic tertiary care center in Riyadh, Saudi Arabia between February 2013 and March 2017.

RESULTS

One hundred patients with depth of invasion staged as T3/T4 or T2 in 93 and seven patients, respectively. Lymph node metastasis was staged as N1/N2 or N0 in 87 and 13 patients, respectively. Circumferential radial margin (CRM) was involved radiologically prior to treatment in 50 patients. A dose of 55 or 50 Gy was given to 71 and 29 patients, respectively. All treatments were completed without interruption. Grade 3/4 toxicity was not observed. Low anterior resection and abdominoperineal resection were performed with negative proximal, distal, and radial margins in 72 and 28 patients, respectively. There were no immediate significant postoperative complications. Histologically, no residual tumor (grade 0) was noted in 20 patients (pCR). Regression grade 1, 2, and 3 were noted in 31, 34, and 15 patients. Average number of lymph nodes retrieved in the surgical specimen was 12 (range 6-22). Lymph nodes were negative for cancer in 80 patients.

CONCLUSION

Dose escalation with SIB-VMAT as NACRT for rectal cancer is feasible. Moreover, it can increase the rate of pathological complete response with a favorable toxicity profile. Clinical benefit of this approach needs to be validated in a larger cohort of patients with longer follow-up.

Preoperative Concomitant Radiotherapy and Chemotherapy in Ultrasound-Staged T3 and T4 Rectal Cancer

Background

To analyze early results of a single institution's experience using neoadjuvant chemoradiotherapy in locally advanced, ultrasound-staged rectal cancer.

Patients and methods

Since 1998, 67 consecutive patients (36 males and 31 females; mean age, 59.5) have received preoperative combined treatment for T3 or T4 rectal cancer. All patients were staged by endorectal ultrasound and computed tomography, and all had a pathology-demonstrated invasive adenocarcinoma of the rectum. Patients were treated preoper-atively with concomitant radiochemotherapy: pelvic irradiation (50 Gy in 25 fractions) and protracted-venous-infusion 5-fluorouracil (225 mg/m2/d, 7 days per week). Patients were restaged within 4 weeks, then submitted to surgery within 6-7 weeks after the end of therapy. Adjuvant postoperative chemotherapy with 5-fluorouracil plus folinic acid - the “de Gramont” schedule – for 24 weeks was purposed to all patients.

Results

Radiotherapy was completed in all cases; only one patient required suspension of the treatment for grade 4 toxicity (diarrhea). Instead, chemotherapy was interrupted in 3 cases (2 for central venous catheter thrombosis and 1 for grade IV diarrhea). Sixty-six patients underwent surgical resection (1 patient died before surgical treatment). Radical surgery was performed in 94%, and 46% of the 26 patients with distal rectal cancer had a conservative sphincter-sparing surgery. A complete pathologic response (defined as no evidence of viable tumor cells) was obtained in 22%. At a median follow-up of 17 months, distant metastases have been observed in 10 patients, and 3 of them developed a local recurrence. The actuarial estimations of 4-year overall survival, disease-free survival, local and distant control are 79%, 61%, 94% and 61%, respectively.

Conclusions

Preoperative chemoradiotherapy seems to be an effective and well-tolerated treatment with a low complication rate. The high percentage of downstaging and sphincter sparing, also in distal rectal cancer, shows the efficacy of the treatment, which could significantly influence the incidence of relapses and quality of life.

Neoadjuvant Therapy of Rectal Cancer New Treatment Perspectives

During the past two decades, significant advances have been made in the management of patients with rectal cancer. A number of clinical studies have demonstrated the efficacy of preoperative chemoradiation therapy with 5-fluorouracil (5-FU)-based regimens in decreasing local recurrences and improving survival and the likelihood of sphincter preservation. Although 5-FU has been the standard drug used in combination with radiation therapy for many years, new effective drugs including capecitabine, raltitrexed, irinotecan and oxaliplatin have been recently investigated in combination with radiation therapy in the preoperative setting. In addition, novel targeted biological agents including epidermal growth factor receptor inhibitors and vascular endothelial growth factor inhibitors have been shown to enhance the antitumor effect of both radiation and chemotherapy and are currently being explored in initial clinical trials. In the present review we summarize the results of adjuvant therapy. In addition, we will discuss the recently reported phase I-II trials with new drug plus radiation combinations in the preoperative treatment of patients with rectal cancer.

Adjuvant Chemotherapy Seemed Not to Have Survival Benefit in Rectal Cancer Patients with ypTis-2N0 After Preoperative Radiotherapy and Surgery from a Population-Based Propensity Score Analysis

BACKGROUND

Adjuvant chemotherapy is currently offered routinely, as standard, after radical resection for patients with rectal cancer receiving neo-adjuvant chemoradiation. However, the efficacy of adjuvant chemotherapy in patients with ypTis-2N0M0 has not been documented to the same extent, and the survival benefit remained controversial. The purpose of this work was to determine the role of chemotherapy in patients with ypTis-2N0M0 classification.

MATERIALS AND METHODS

Data were obtained from the Surveillance, Epidemiology, and End Results database (n = 4,217). A propensity score model was utilized to balance baseline covariates.

RESULTS

Of the 4,217 included patients, 335 with ypTis-2N0M0 did not receive adjuvant chemotherapy. There were comparable cancer-specific survivals (CSS) between those undergoing adjuvant chemotherapy or not (log-rank test = 0.136, p = .712) in the overall sample. After propensity score matching, the cancer-specific survival did not differ between the chemotherapy and observation groups (log-rank test = 0.089, p = .765). Additionally, the Cox model did not demonstrate adjuvant chemotherapy as the prognostic factor, with hazard ratio = 0.95 (95% confidence interval 0.69-1.32) for CSS. Furthermore, the 10-year cumulative CSS was 78.7% and 79.4% between the chemotherapy and observation groups, indicating no significance, and no impact of adjuvant chemotherapy on survival was observed in different subgroups stratified by T stage, histological grade, histology, lymph nodes, and tumor size.

CONCLUSION

Patients with ypTis-2N0 rectal cancer did not benefit from adjuvant chemotherapy after preoperative radiology and radical surgery in this cohort study. These results provided new insight into the routine use of adjuvant chemotherapy for patients with rectal cancer with completed neo-adjuvant radiotherapy and curative surgery.

IMPLICATIONS FOR PRACTICE

Inconsistent recommendations for patients with rectal cancer receiving neo-adjuvant chemoradiation are offered by clinical guidelines. Adjuvant chemotherapy had no cancer-specific survival benefit, not only in the whole cohort, but also in the propensity score-matched cohort. A Cox model also confirmed adjuvant chemotherapy was not a significant prognostic factor in ypTis-2N0 rectal cancer. No survival benefit conferred by adjuvant chemotherapy was observed, regardless of whether T stage, histological type, grade, lymph nodes and tumor size varied.

Meta-analysis of oxaliplatin-based versus fluorouracil-based neoadjuvant chemoradiotherapy and adjuvant chemotherapy for locally advanced rectal cancer

A meta-analysis was conducted to compare oxaliplatin-based with fluorouracil-based neoadjuvant chemoradiotherapy and adjuvant chemotherapy for locally advanced rectal cancer. MEDLINE, EMBASE and CENTRAL were systematically searched for relevant randomized controlled trials (RCTs) until January 31 2017. Review Manager (version 5.3) was used to analyze the data. Dichotomous data were calculated by odds ratio (OR) with 95% confidence intervals (CI). A total of 8 RCTs with 6103 stage II or III rectal cancer patients were analyzed, including 2887 patients with oxaliplatin+fluorouracil regimen and 3216 patients with fluorouracil alone regimen. Compared with fluorouracil-based regimen group, oxaliplatin-based regimen group attained higher pathologic complete response (OR = 1.29, 95% CI: 1.12−1.49, P = 0.0005) and 3-year disease-free survival (OR = 1.15, 95% CI: 0.93−1.42, P = 0.21), but suffered greater toxicity (OR = 2.07, 95% CI: 1.52−2.83, P < 0.00001). Also, there were no significant differences between two regimens in sphincter-sparing surgery rates (OR = 0.94, 95% CI: 0.83−1.06, P = 0.33), 5-year disease-free survival (OR = 1.15, 95% CI: 0.93−1.42, P = 0.21) and overall survival (3-year, OR = 1.14, 95% CI: 0.98−1.34, P = 0.09; 5-year, OR = 1.06, 95% CI: 0.78−1.44, P = 0.70). In conclusion, the benefits of adding oxaliplatin to fluorouracil-based neoadjuvant chemoradiotherapy and adjuvant chemotherapy for locally advanced rectal cancer remains controversial, and cannot be considered a standard approach.

Ginsenoside Rg3 Sensitizes Colorectal Cancer to Radiotherapy through Downregulation of Proliferative and Angiogenic Biomarkers

Background

Radiation therapy is an important mode of colorectal cancer treatment. However, most people die of local recurrence after tumors become resistant to radiotherapy, and little progress has been made in treating radiotherapy-resistant colorectal cancer. Hence, novel agents that are nontoxic and can sensitize colorectal cancer to radiotherapy are urgently needed. Ginsenoside Rg3, a saponin extracted from ginseng, shows cytotoxicity against a variety of cancer cells through suppression of pathways linked to oncogenesis, including cell survival, proliferation, invasion, and angiogenesis. In this article, we investigated whether Rg3 can sensitize colorectal cancer to radiation in vivo.

Methods and Materials

We established CT-26 xenografts in BALB/c mice and treated them with vehicle, Rg3, radiation, and combined Rg3 + radiation. Mouse quality of life, survival, tumor volumes, and inhibitive rates were estimated. NF-κB activation was ascertained using electrophoretic mobility shift assay and immunohistochemistry. We also tested for markers of proliferation, angiogenesis, and invasion using immunohistochemistry and Western blot analysis.

Results

Rg3 significantly enhanced the efficacy of fractionated radiotherapy by improving the quality of life of mice. Moreover, tumors from mice xenografted with CT-26 cells and treated with combined Rg3 + radiotherapy showed significantly lower tumor volumes (P < 0.01 versus controls; P < 0.05 versus radiation alone), NF-κB activation, and expression of NF-κB-regulated gene products (cyclin D1, survivin, cyclooxygenase-2 (COX-2), and vascular endothelial growth factor (VEGF)) compared with controls. The combination treatment was also effective in suppressing angiogenesis, as indicated by lower CD31⁺ microvessel density compared with controls (P < 0.05).

Conclusion

Our results suggest that Rg3 enhances the antitumor effects of radiotherapy for colorectal cancer by suppressing NF-κB and NF-κB-regulated gene products, leading to inhibition of tumors and prolongation of the lifespan of CT-26 xenograft BALB/c mice.

The efficacy of adding targeted agents to neoadjuvant therapy for locally advanced rectal cancer patients: a meta-analysis

Patients with locally advanced rectal cancer (LARC) are at tremendous risk of metastatic diseases. To improve the prognoses of LARC patients, the efficacy of adding targeted agents to neoadjuvant therapy has been investigated by many researchers but remains controversial. A literature search of relevant databases was conducted through December 2016, 804 studies were identified and 32 investigations were ultimately included. A total of 1196 patients from 31 cohorts of 29 studies were eligible for quantitative synthesis in this single‐arm setting meta‐analysis. As pathologic complete response (pCR) shows promise as a prognosis indicator, we focused on pCR rates to evaluate whether adding targeted agents to neoadjuvant therapies improves the outcome of LARC patients. In our study, we revealed pooled estimates of pCR of 27% (95%CI, 21–34%) and 14% (95%CI, 9–21%) for bevacizumab‐relevant cohorts and cetuximab‐relevant cohorts, respectively. The safety of adding targeted agents to neoadjuvant therapy was also evaluated by pooling the data of Grade 3/4 toxicity. In conclusion, our study revealed that adding bevacizumab to the neoadjuvant therapy regimens provides appreciable pCR for LARC patients. Meanwhile, the efficacy of cetuximab remains inconclusive, RCTs with larger scale and better study design that stress more on mutational status are needed.

Prognostic value of neoadjuvant treatment response in locally advanced rectal cancer

BACKGROUND

For locally advanced rectal cancer, response to neoadjuvant radiation has been associated with improved outcomes but has not been well characterized in general practice. The goals of this study were to describe disease response rates after neoadjuvant treatment and to evaluate the association between disease response and survival.

MATERIALS AND METHODS

Retrospective cohort study of patients aged 18-80 y with clinical stage II and III rectal adenocarcinoma in the National Cancer Database (2006-2012). All patients underwent radical resection after neoadjuvant treatment. Treatment responses were defined as follows: no tumor response; intermediate-T and/or N downstaging with residual disease; and complete-ypT0N0. Multivariable, multinomial regression was used to evaluate the association between neoadjuvant radiation use and disease response. Multivariable Cox regression was used to evaluate the association between disease response and overall risk of death.

RESULTS

Among 12,024 patients, 12% had a complete and 30% an intermediate response. Neoadjuvant chemotherapy alone was less likely to achieve an intermediate (relative risk ratio: 0.70 [0.56-0.88]) or a complete response (relative risk ratio: 0.59 [0.41-0.84]) relative to neoadjuvant radiation. Tumor response was associated with improved 5-y overall survival (complete = 90.2%, intermediate = 82.0%, no response = 70.5%; log-rank, P < 0.001). Complete and intermediate pathologic responses were associated with decreases in risk of death (hazard ratio: 0.40 [0.34-0.48] and 0.63 [0.57-0.69], respectively) compared to no response. Primary tumor and nodal response were independently associated with decreased risk of death.

CONCLUSIONS

Neoadjuvant radiation is associated with treatment response, and pathologic response is associated with improved survival. Pathologic response may be an early benchmark for the oncologic effectiveness of neoadjuvant treatment.

Predictors of Sensitivity to Preoperative Chemoradiotherapy of Rectal Adenocarcinoma

Objectives

The purpose of the study was to identify predictive factors of tumor response to preoperative chemoradiotherapy for rectal adenocarcinoma.

Methods

Ninety-eight patients with nonmetastatic rectal adenocarcinoma received preoperative concurrent chemoradiotherapy and underwent mesorectal excision. After treatment, tumor response according to tumor regression grade were evaluated. The correlation of clinicopathologic factors to tumor response was analyzed.

Results

The results from a univariate analysis indicated that pretreatment carcinoembryonic antigen level ≤3.0 ng/ml (P = 0.002), non-fixed tumor (P = 0.001), and tumor circumferential extent ≤50% (P = 0.001) were associated significantly with a good tumor response. They also indicated that pretreatment positive lymph nodes (P = 0.032) were associated significantly with a poor tumor response. In multivariate analysis, the results indicated that pretreatment carcinoembryonic antigen level (hazard ratio, 2.930; P = 0.003), tumor mobility (hazard ratio, 2.651; P = 0.002) and circumferential extent of tumor (hazard ratio, 2.394; P = 0.019) independently predicted a good pathologic response rate. Pretreatment positive lymph nodes were not significantly associated with a good response (hazard ratio, 0.361; P = 0.191).

Conclusions

Pretreatment carcinoembryonic antigen level, tumor mobility and circumferential extent of tumor may be helpful in predicting responsiveness in rectal adenocarcinoma to preoperative chemoradiotherapy, although the results should be confirmed in larger, more homogeneous studies.

Recombinant human endostatin combined with radiotherapy inhibits colorectal cancer growth

BACKGROUND

To examine the effects of recombinant human endostatin combined with radiotherapy on colorectal cancer HCT-116 cell xenografts in nude mice.

METHODS

Forty male BALB/c nude mice were injected with human colorectal cancer HCT-116 cells to form xenografts and then randomized into the following 4 groups (each group comprised ten mice): a control group, an endostatin group (20 mg/kg endostatin once a day for 10 days), a radiotherapy group (a 6-Gy dose was administered via a 6-MV X-ray on day 5 post-inoculation), and a combination therapy group (radiotherapy with endostatin treatment). The tumor growth inhibition rate were detected. CD31, vascular endothelial growth factor (VEGF), and hypoxia inducible factor-1α (HIF-1α) expression and microvascular density (MVD) were evaluated by immunohistochemistry. The expression of VEGF protein was also detected by western blotting.

RESULTS

The tumor growth inhibition rate in the radiotherapy with endostatin treatment group was significantly higher than those in endostatin group or radiotherapy group (77.67% vs 12.31% and 38.59%; n = 8 per group, P < 0.05). The results of immunohistochemistry showed that treatment with radiotherapy induced significant increases in CD31, VEGF, and HIF-1α expression and MVD compared with treatment with saline, while treatment with endostatin or radiotherapy with endostatin induced reductions in CD31, VEGF, and HIF-1α expression and MVD compared with treatment with saline (n = 8 per group, P < 0.05). The results of western blotting showed that VEGF protein expression in radiotherapy group was significantly increased compared with that in the control group. However, VEGF protein expression in the endostatin or radiotherapy with endostatin groups was significantly decreased compared with that in the control group (n = 8 per group, P < 0.05).

CONCLUSIONS

Endostatin combined with radiotherapy can significantly inhibit HCT-116 cell xenograft growth, possibly by inhibiting angiogenesis and attenuating tumor cell hypoxia.

Prognostic significance of tumour regression grade after neoadjuvant chemoradiotherapy for a cohort of patients with locally advanced rectal cancer: an 8-year retrospective single-institutional study

AIM

Locally advanced rectal cancer (LARC) is frequently treated with neoadjuvant chemoradiotherapy (NACRT) to reduce the risk of local recurrence and improve survival. Tumour response to NACRT is variable and may influence the prognosis after subsequent surgery. This study compared the prognostic values of tumour regression grade (TRG) and neoadjuvant pathological (ypTNM) downstaging in patients with Stage II and III rectal cancer treated with NACRT followed by curative surgery.

METHOD

This study included 185 patients with LARC treated with long-course radiotherapy (45 Gy in 25 fractions) plus 5-fluorouracil over 5 weeks between 2005 and 2013. We used multivariate analysis to assess the relationship of Dworak's five-tier TRG, ypTNM stage and ypTNM downstaging with clinicopathological factors, 5-year disease-free survival (DFS) and 5-year overall survival (OS).

RESULTS

Total regression (TRG4), good regression (TRG3), moderate regression (TRG2), minor regression (TRG1) and no regression (TRG0) were seen in 38 (20.6%), 65 (35.2%), 43 (23.2%), 28 (15.1%) and 11 (5.9%) patients, respectively. TNM downstaging following NACRT occurred in 109 (58.9%) patients. The 5-year DFS rates after NACRT for TRG0, TRG1, TRG2, TRG3 and TRG4 were 0%, 58.5%, 66.4%, 80.4% and 82.6%, respectively (P < 0.001). The ypTNM stage correlated with 5-year DFS (P = 0.004) but not 5-year OS (P = 0.075). Multivariate analysis demonstrated that TRG was related to both DFS and OS (P < 0.001).

CONCLUSION

TRG measured on a five-tier system was better than ypTNM stage for predicting outcome in patients with LARC treated with NACRT and surgery.

Adjuvant chemotherapy may improve disease-free survival in patients with rectal cancer positive for MRI-detected extramural venous invasion following chemoradiation

AIM

MRI-detected extramural venous invasion (mrEMVI) is a poor prognostic factor in rectal cancer. Preoperative chemoradiotherapy (CRT) can cause regression in the severity of EMVI and subsequently improve survival whereas mrEMVI persisting after CRT confers an increased risk of recurrence. The effect of adjuvant chemotherapy (AC) following CRT on survival in rectal cancer remains unclear. The aim of this study was to determine whether there is a survival advantage for AC given to patients with mrEMVI persisting after CRT.

METHOD

A prospective analysis was conducted of consecutive patients with locally advanced rectal cancer between 2006 and 2013. All patients underwent CRT followed by surgery. AC was given to selected patients based on the presence of specific 'high-risk' features. Comparison was made between patients offered AC with observation alone. The primary outcome was 3-year disease-free survival (DFS).

RESULTS

Of 631 patients, 227 (36.0%) demonstrated persistent mrEMVI following CRT. Patients were grouped on the basis of AC or observation and were matched for age, performance status and final histopathological staging. Three-year DFS in the AC group was 74.6% compared with 53.7% in the observation only group. AC had a survival benefit on multivariate analysis (hazard ratio 0.458; 95% CI: 0.271-0.775, P = 0.004).

CONCLUSION

Patients with persistent mrEMVI following CRT who receive AC may have a decreased risk of recurrence and an improved 3-year DFS compared with patients not receiving AC, irrespective of age and performance status.

Tumor compactness improves the preoperative volumetry-based prediction of the pathological complete response of rectal cancer after preoperative concurrent chemoradiotherapy

In addition to clinical factors (tumor and node stage) and treatment factors (equivalent radiotherapy dose and chemotherapy regimen), we assessed whether different performances of various tumor volume measurements help predict the pathological complete response (pCR) of locally advanced rectal cancer (LARC) after preoperative concurrent chemoradiotherapy (CCRT). A total of 122 patients with LARC treated with a long course of CCRT, between December 2009 and March 2015, were enrolled in this bi-institutional study. Tumor delineation was based on standard T2-weighted magnetic resonance imaging or contrast-enhanced computed tomography before CCRT. Tumor compactness was defined as the ratio of the volume and the surface area. The tumor compactness-corrected TV (TCTV) was defined as the ratio of the real TV (RTV) and tumor compactness. Twenty-three (18.9%) patients had a pCR. Areas under the curve of the receiver operating characteristic for pCR prediction calculated using the RTV, cylindrical approximated TV (CATV), and TCTV were 0.724, 0.747, and 0.780, respectively. The prediction performance of TCTV was significantly more efficient than that of both RTV (P = 0.0057) and CATV (P = 0.0329). Multivariate logistic regression analysis revealed tumor compactness (P = 0.001), RTV (P = 0.042), and preoperative clinical nodal status (P = 0.044) as significant predictors of a pCR. In addition, poor tumor compactness was closely associated with lymphovascular space invasion (P = 0.008) and pathological nodal status (P = 0.003). For patients with LARC receiving preoperative CCRT, tumor compactness is a useful radiomic parameter for improving the volumetric based prediction model.

Value of diffusion-weighted MRI and apparent diffusion coefficient measurements for predicting the response of locally advanced rectal cancer to neoadjuvant chemoradiotherapy

PURPOSE

The aim of our study was to assess the performance value of magnetic resonance imaging (MRI) in the restaging of locally advanced rectal cancer after neoadjuvant chemoradiotherapy (CRT) and in the identification of good vs. poor responders to neoadjuvant therapy.

MATERIALS AND METHODS

A total of 34 patients with locally advanced rectal cancer underwent MRI prior to and after CRT. T stage and tumor regression grade (TRG) on post-CRT MRI was compared with the pathological staging ypT and TRG. Tumor volume and the apparent diffusion coefficient (ADC) were measured using diffusion-weighted imaging (DWI) before and after neoadjuvant CRT; the percentage of tumor volume reduction and the change of ADC (ΔADC) was also calculated. ADC parameters and the percentage of tumor volume reduction were correlated to histopathological results. The diagnostic performance of ADC and volume reduction to assess tumor response was evaluated by calculating the area under the ROC curve and the optimal cut-off values.

RESULTS

A significant correlation between the T stage and the TRG defined in DW-MRI after CRT and the ypT and the TRG observed on the surgical specimens was found (p = 0.001; p < 0.001). The mean post-CRT ADC and ΔADC in responder patients was significantly higher compared to non-responder ones (p = 0.001; p = 0.01). Furthermore, the mean post-CRT ADC values were significantly higher in tumors with T-downstage (p = 0.01).

CONCLUSION

DW-MRI may have a significant role in the restaging and in the evaluation of post-CRT response of locally advanced rectal cancer. Quantitative analysis of DWI through ADC map may result in a promising noninvasive tool to evaluate the response to therapy.

Pathologic response to neoadjuvant treatment in locally advanced rectal cancer and impact on outcome

BACKGROUND

Downstaging and pathologic complete response (pCR) after chemoradiotherapy (CRT) may improve progression-free survival and overall survival (OS) after curative therapy of locally advanced adenocarcinoma of rectum. The purpose of this study is to evaluate the pathologic response subsequent to neoadjuvant chemoradiation in locally advanced rectal adenocarcinoma and any impact of response on oncological outcome [disease-free survival (DFS), OS].

METHODS

A total of 127 patients with histologically-proven rectal adenocarcinoma, locally advanced, were treated with preoperative radiotherapy and concurrent 5-fluorouracil (5 FU), and followed by curative surgery. Pathologic response to neoadjuvant treatment was evaluated by comparing pathologic TN (tumour and nodal) staging (yp) with pre-treatment clinical staging. DFS and OS were compared in patients with: pCR, partial pathologic response and no response to neoadjuvant therapy.

RESULTS

14.96% (19 patients) had a pCR, 58.27% [74] showed downstaging and 26.77% [34] had no change in staging. At follow-up (range, 4-9 years, median 6 years 2 months or 74 months), 17.32% [22] showed recurrence: 15.74% [20] distant metastasis, 1.57% [2] pelvic failure. 10.5% [2] of the patients with pCR showed distant metastasis, none showed local recurrence. In the downstaged group, nine developed distant failure and two had local recurrence (14.86%). Distant failure was seen in 26.47% [9] of those with no response to neoadjuvant treatment. DFS and OS rates for all groups were 82.67% and 88.97% respectively. Patients with pCR showed 89.47% DFS and 94.7% OS. In partial responders, DFS was 85.1% and OS was 90.5%. In non-responders, DFS and OS were 73.5% and 82.3% respectively. Patients with pCR had a significantly greater probability of DFS and OS than non-responders. Rectal cancer-related death was 11.02% [14]: one patient (5.26%) with pCR, 9.47% [7] in the downstaged group and 17.64% [6] of non-responders.

CONCLUSIONS

The majority of patients showed some response to neoadjuvant treatment. Findings of this study indicate tumour response to neoadjuvant CRT improves the long-term outcome, with a better result in patients with pCR.

Value of percent change in tumoral volume measured at T2 -weighted and diffusion-weighted MRI to identify responders after neoadjuvant chemoradiation therapy in patients with locally advanced rectal carcinoma

PURPOSE

To evaluate the percent change in tumoral volume measured at T₂ -weighted magnetic resonance imaging (T₂ WMRI) and diffusion-weighted (DWI) as a method to identify responders after chemo- and radiation therapy (CRT) in patients with locally advanced rectal carcinoma.

MATERIALS AND METHODS

Forty-five consecutive patients (mean age ± SD: 72 years ± 9.7; male/female = 24/21) with locally advanced rectal carcinoma underwent CRT followed by surgery. Each patient underwent T₂ WMRI and DWI at 1.5T before and 6 weeks after the completion of CRT. The percent change in tumoral volume before and 6 weeks after CRT was compared in patients classified as responders and nonresponders according to rectal cancer regression grade.

RESULTS

Twenty-five patients were classified as responders with either partial (n = 20) or complete response (n = 5), while 20 patients were classified as nonresponders due to stable disease (n = 18) or disease progression (n = 2). Responders vs. nonresponders differed in the percent change of tumoral volume at T₂ WMRI (-67% ± 26% vs. -29% ± 26%; P < 0.05) and DWI images (-72% ± 24% vs. -33% ± 28%; P < 0.05) with a cutoff ≤ -70% for T₂ WMRI (sensitivity = 69%, 95% confidence interval [CI]: 48-85%; specificity = 100%, 95% CI 81-100%) and ≤66% for DWI (sensitivity = 73%, 95% CI: 52-88%; specificity = 100%, 95% CI 81-100%).

CONCLUSION

The percent change in tumoral volume at T₂ WMRI and DWI images can differentiate responders from nonresponders in patients with locally advanced rectal carcinoma after neoadjuvant CRT. J. Magn. Reson. Imaging 2016;44:1415-1424.

Targeting the 19S proteasomal subunit, Rpt4, for the treatment of colon cancer

Deregulation of the ubiquitin-proteasome pathway has been frequently observed in a number of malignancies. Using quantitative Western blotting of normal and matched tumour tissue, we here identified a significant increase in the 19S proteasome subunit Rpt4 in response to chemoradiation in locally advanced rectal cancer patients with unfavourable outcome. We therefore explored the potential of Rpt4 reduction as a therapeutic strategy in colorectal cancer (CRC). Utilizing siRNA to down regulate Rpt4 expression, we show that silencing of Rpt4 reduced proteasomal activity and induced endoplasmic reticulum stress. Gene silencing of Rpt4 also inhibited cell proliferation, reduced clonogenic survival and induced apoptosis in HCT-116 colon cancer cells. We next developed a cell penetrating peptide-based nanoparticle delivery system to achieve in vivo gene silencing of Rpt4. Administration of Rpt4 siRNA nanoparticles reduced tumour growth and improved survival in a HCT-116 colon cancer xenograft tumour model in vivo. Collectively, our data suggest that inhibition of Rpt4 represents a novel strategy for the treatment of CRC.

Adjuvant chemotherapy for rectal cancer: Is it needed?

Adjuvant chemotherapy has become a standard treatment of advanced rectal cancer in the West. The benefits of adjuvant chemotherapy after surgery alone have been well established. However, controversy surrounds the use adjuvant chemotherapy in patients who received preoperative chemoradiotherapy, despite it being recommended by a number of international guidelines. Results of recent multicentre randomised control trials showed no benefit of adjuvant chemotherapy in terms of survival and rates of distant metastases. However, concerns exist regarding the quality of the studies including inadequate staging modalities, out-dated chemotherapeutic regimens and surgical approaches and small sample sizes. It has become evident that not all the patients respond to adjuvant chemotherapy and more personalised approach should be employed when considering the benefits of adjuvant chemotherapy. The present review discusses the strengths and weaknesses of the current evidence-base and suggests improvements for future studies.

Association of beclin 1 expression with response to neoadjuvant chemoradiation therapy in patients with locally advanced rectal carcinoma

Beclin 1 is an essential regulator of autophagy that is induced in response to cellular stress and serves to maintain cell survival in established tumors. We recently demonstrated that Beclin 1 suppression can sensitize colorectal cancer cells to radiation-induced DNA damage and apoptosis. Therefore, we hypothesized that the level of Beclin 1 expression may be associated with radiation sensitivity in vivo. We determined the association of Beclin 1 expression in pretreatment rectal cancer tissues with response to neoadjuvant chemoradiation in surgical resection specimens. Stages II and III (n = 96) rectal adenocarcinoma patients were treated with neoadjuvant chemoradiation followed by surgical resection with curative intent. Beclin 1 was analyzed by immunohistochemistry and the expression level was dichotomized at the median value with categorization into low and high groups. We identified 56 (58.3%) and 40 (41.7%) patients whose tumors had high- versus low-level Beclin 1 expression, respectively. Rectal cancers with high versus low Beclin 1 expression were significantly less likely to be downstaged after chemoradiation treatment (45% [25/55] vs. 58% [22/38]; p = 0.02). In a multivariable analysis adjusted for age, sex, histological grade and baseline tumor node metastasis (TNM) stage, the impact of Beclin 1 expression on tumor downstaging remained statistically significant (p = 0.03). The association of the level of Beclin 1 expression with the rate of tumor downstaging after chemoradiation is consistent with in vitro data, and suggests that Beclin 1 may be a predictive biomarker for the efficacy of chemoradiation in patients with rectal cancer.

Prognostic significance of pathological response to preoperative chemoradiotherapy in patients with locally advanced rectal cancer

BACKGROUND

Preoperative chemoradiotherapy (CRT) is widely used in the treatment of locally advanced rectal cancer (LARC). Pathological response to CRT has been shown to be a potential prognostic predictor in rectal cancer patients. The aim of this study was to determine the prognostic significance of pathological response to preoperative CRT in LARC patients.

METHODS

Thirty-two patients with LARC were retrospectively analyzed to determine the relationships of pathological response and clinicopathological characteristics to survival outcomes. Patients received CRT with tegafur/uracil and leucovorin. Radiotherapy was administered in fractions of 1.8 Gy/day and 5 days per week. The total dose of radiation delivered was 45 Gy.

RESULTS

All patients underwent total mesorectal excision with lymph node dissections after CRT, and resected specimens were examined pathologically. Four patients showed pathological complete response, 14 showed good response, and 14 showed poor response. Pathological complete or good response was associated with longer survival (P = 0.041). Clinicopathological factors excluding gender were not correlated with outcome. No factor was associated with recurrence.

CONCLUSION

Pathological response to preoperative CRT may be a useful prognostic predictor in patients with LARC.

Prognostic significance of pathological response to preoperative chemoradiotherapy in patients with locally advanced rectal cancer

BACKGROUND

Preoperative chemoradiotherapy (CRT) is widely used in the treatment of locally advanced rectal cancer (LARC). Pathological response to CRT has been shown to be a potential prognostic predictor in rectal cancer patients. The aim of this study was to determine the prognostic significance of pathological response to preoperative CRT in LARC patients.

METHODS

Thirty-two patients with LARC were retrospectively analyzed to determine the relationships of pathological response and clinicopathological characteristics to survival outcomes. Patients received CRT with tegafur/uracil and leucovorin. Radiotherapy was administered in fractions of 1.8 Gy/day and 5 days per week. The total dose of radiation delivered was 45 Gy.

RESULTS

All patients underwent total mesorectal excision with lymph node dissections after CRT, and resected specimens were examined pathologically. Four patients showed pathological complete response, 14 showed good response, and 14 showed poor response. Pathological complete or good response was associated with longer survival (P = 0.041). Clinicopathological factors excluding gender were not correlated with outcome. No factor was associated with recurrence.

CONCLUSION

Pathological response to preoperative CRT may be a useful prognostic predictor in patients with LARC.

MRI for Assessing Response to Neoadjuvant Therapy in Locally Advanced Rectal Cancer Using DCE-MR and DW-MR Data Sets: A Preliminary Report

To evaluate MRI for neoadjuvant therapy response assessment in locally advanced rectal cancer (LARC) using dynamic contrast enhanced-MRI (DCE-MRI) and diffusion weighted imaging (DWI), we have compared magnetic resonance volumetry based on DCE-MRI (V(DCE)) and on DWI (V(DWI)) scans with conventional T2-weighted volumetry (V(C)) in LARC patients after neoadjuvant therapy. Twenty-nine patients with LARC underwent MR examination before and after neoadjuvant therapy. A manual segmentation was performed on DCE-MR postcontrast images, on DWI (b-value 800 s/mm²), and on conventional T2-weighted images by two radiologists. DCE-MRI, DWI, and T2-weigthed volumetric changes before and after treatment were evaluated. Nonparametric sample tests, interobserver agreement, and receiver operating characteristic curve (ROC) were performed. Diagnostic performance linked to DCE-MRI volumetric change was superior to T2-w and DW-MRI volumetric changes performance (specificity 86%, sensitivity 93%, and accuracy 93%). Area Under ROC (AUC) of V(DCE) was greater than AUCs of V(C) and V(DWI) resulting in an increase of 15.6% and 11.1%, respectively. Interobserver agreement between two radiologists was 0.977, 0.864, and 0.756 for V(C), V(DCE), and V(DWI), respectively. V(DCE) seems to be a promising tool for therapy response assessment in LARC. Further studies on large series of patients are needed to refine technique and evaluate its potential value.

Role of Adjuvant Chemotherapy in ypT0-2N0 Patients Treated with Preoperative Chemoradiation Therapy and Radical Resection for Rectal Cancer

OBJECTIVE

To explore the role of adjuvant chemotherapy for patients with ypT0-2N0 rectal cancer treated by preoperative chemoradiation therapy (PCRT) and radical resection.

PATIENTS AND METHODS

A national consortium of 10 institutions was formed, and patients with ypT0-2N0 mid- and low-rectal cancer after PCRT and radical resection from 2004 to 2009 were included. Patients were categorized into 2 groups according to receipt of additional adjuvant chemotherapy: Adj CTx (+) versus Adj CTx (-). Propensity scores were calculated and used to perform matched and adjusted analyses comparing relapse-free survival (RFS) between treatment groups while controlling for potential confounding.

RESULTS

A total of 1016 patients, who met the selection criteria, were evaluated. Of these, 106 (10.4%) did not receive adjuvant chemotherapy. There was no overall improvement in 5-year RFS as a result of adjuvant chemotherapy [91.6% for Adj CTx (+) vs 87.5% for Adj CTx (-), P=.18]. There were no differences in 5-year local recurrence and distant metastasis rate between the 2 groups. In patients who show moderate, minimal, or no regression in tumor regression grade, however, possible association of adjuvant chemotherapy with RFS would be considered (hazard ratio 0.35; 95% confidence interval 0.14-0.88; P=.03). Cox regression analysis after propensity score matching failed to show that addition of adjuvant chemotherapy was associated with improved RFS (hazard ratio 0.81; 95% confidence interval 0.39-1.70; P=.58).

CONCLUSIONS

Adjuvant chemotherapy seemed to not influence the RFS of patients with ypT0-2N0 rectal cancer after PCRT followed by radical resection. Thus, the addition of adjuvant chemotherapy needs to be weighed against its oncologic benefits.

Oncologic results and prognostic predictors of patients with locally advanced rectal cancer showing ypN0 after radical surgery following neoadjuvant chemoradiotherapy

PURPOSE

Adjuvant chemotherapy is recommended for patients with locally advanced rectal cancer after radical surgery following neoadjuvant chemoradiotherapy (NCRT) regardless of the final pathologic stage. However, the efficacy of adjuvant chemotherapy in ypN0 patients remains controversial. The aim of this study was to evaluate the oncologic outcomes and analyze the prognostic factors for ypN0 patients in order to estimate prognosis and establish an effective adjuvant chemotherapy strategy for stage 0-II rectal cancers after radical surgery following NCRT.

METHODS

Between January 1999 and December 2009, the medical records of 202 patients who had been diagnosed with locally advanced rectal cancer, underwent radical surgery following NCRT, and showed ypN0 were retrospectively reviewed.

RESULTS

The median follow-up period was 60.5 months. The 5-year local recurrence rate was 3.1 %. The 5-year disease-free survival and 5-year overall survival were 86.3 and 86.9 %. Postirradiation T3-4 and abdominoperineal resection (APR) were the independent prognostic indicators for disease-free survival (p = 0.001, p = 0.003) and overall survival (p = 0.001, p = 0.002). Adjuvant chemotherapy improved local recurrence in the patient with ypT3-4 and patients who had undergone APR (p = 0.014, p = 0.002). APR affected local recurrence, disease-free survival, and overall survival of ypT3-4 patients (p = 0.013. 0.029, and 0.001) CONCLUSIONS: Postirradiation T3-4 and APR are the significant prognostic factors for ypN0. Further randomized prospective study is needed to evaluate the oncologic benefit of adjuvant chemotherapy in ypN0 patients, especially those with ypT3-4 and those having undergone APR, and to confirm which chemotherapeutic agent could improve the oncologic outcomes of patients poorly responding to NCRT.

High levels of X-linked Inhibitor-of-Apoptosis Protein (XIAP) are indicative of radio chemotherapy resistance in rectal cancer

BACKGROUND

The mainstay of treatment in rectal cancer is neoadjuvant radio chemotherapy prior to surgery, in an attempt to downstage the tumour, allowing for more complete removal during surgery. In 40 % of cases however, this neoadjuvant radio chemotherapy fails to achieve tumour regression, partly due insufficient apoptosis signaling. X-linked Inhibitor of Apoptosis Protein (XIAP) is an anti-apoptotic protein that has been reported to contribute to disease progression and chemotherapy resistance.

METHODS

We obtained rectal biopsy normal and matched tumour tissue from 29 rectal cancer patients with varying degrees of tumour regression, and using Western blot, examined anti-apoptotic XIAP and pro-apoptotic Smac protein levels in these tissues, with the aim to examine whether disturbed XIAP/Smac levels may be an indicator of neoadjuvant radio chemotherapy resistance. Expression of inhibitor of apoptosis proteins cIAP-1 and cIAP-2 was also examined.

RESULTS

We found that levels of XIAP increased in accordance with the degree of radio chemotherapy resistance of the tissue. Levels of this protein were also significantly higher in tumour tissue, compared to matched normal tissue in highly resistant tissue. In contrast, Smac protein levels did not increase with radio chemotherapy resistance, and the protein was similarly expressed in normal and tumour tissue, indicating a shift in the balance of these proteins. Post treatment surgical resection tissue was available for 8 patients. When we compared matched tissue pre- and post- radio chemotherapy we found that XIAP levels increased significantly during treatment in both normal and tumour tissue, while Smac levels did not change. cIAP-1 and cIAP-2 levels were not differentially expressed in varying degrees of radio chemotherapy resistance, and neoadjuvant therapy did not alter expression of these proteins.

CONCLUSION

These data indicate that disturbance of the XIAP/Smac balance may be a driver of radio chemotherapy resistance, and hence high levels of XIAP may be a useful indicator of neoadjuvant radio chemotherapy resistance in rectal cancer. Moreover, as XIAP levels increase with radio chemotherapy it is possible that a subset of more resistant tumour cells survive this treatment and may be resistant to further adjuvant treatment. Patients with resistant tumours highly expressing XIAP may benefit from alternative treatment strategies, such as Smac mimetics post neoadjuvant radio chemotherapy.