Clinical outcome of neoadjuvant chemoradiation therapy with oxaliplatin and capecitabine or 5-fluorouracil for locally advanced rectal cancer

Prognosis and risk factors for the development of pulmonary metastases after preoperative chemoradiotherapy and radical resection in patients with locally advanced rectal cancer

Background

Although preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) is currently considered effective for treating locally advanced rectal cancer (LARC), a proportion of patients develop postoperative pulmonary metastases. The current study aimed to assess the prognostic characteristics and risk factors for the development of rectal cancer pulmonary metastases after CRT and radical resection.

Methods

We retrospectively analyzed data collected on 544 consecutive patients who were diagnosed with LARC and underwent preoperative CRT followed by tumor radical resection between December 2003 and June 2014. Overall survival (OS), disease-free survival (DFS), and pulmonary metastasis rates were calculated and compared among the subgroups, and risk factors for pulmonary metastases were identified by Cox models.

Results

A total of 61 (11.2%) patients developed pulmonary metastases postoperatively, 45 of whom (73.8%) developed the condition in the first 24 months. The 1-, 2-, and 3-year pulmonary metastasis rates were 6.7%, 10.4%, and 11.7%, respectively. Compared with the disease-free group, the pulmonary metastases group had a significantly lower proportion of downstaging and pathological complete regression (pCR) rate and a significantly higher proportion of low rectum tumor. In multivariate analysis, a distance of the tumor ≤5 cm from the anal verge [hazard ratio (HR), 1.394; 95% confidence interval (CI), 1.211-3.736; P=0.003] was identified as an independent negative predictor of the 3-year pulmonary metastasis rate, and N0 stage (HR, 0.490; 95% CI, 0.261-0.919; P=0.026) and TNM downstaging (HR, 0.514; 95% CI, 0.265-0.997; P=0.049) were identified as independent positive predictors of the 3-year pulmonary metastasis rate.

Conclusions

Pulmonary metastases warranted a more intensive follow-up in patients with low rectal cancer, lymph node metastases and poor response after preoperative CRT and radical tumor resection.

Unintended consequences of treating early rectal cancers for complete clinical response with chemoradiotherapy

The aim was to examine the current trend in rectal cancer, which is to extend ’watch-and-wait’ to earlier-stage tumors, not normally treated with chemoradiotherapy, to define the up-side and down-side regarding quality of life (QOL) and anorectal/sexual/urinary function from this approach. We reviewed the literature regarding a ‘watch-and-wait’ strategy after neoadjuvant chemoradiotherapy. The primary outcome measure was complete clinical response. Secondary measures included colostomy rate, functional outcomes and QOL. There is a trend to use chemoradiotherapy in earlier tumors using dose-escalation of radiation and/or additional chemotherapy, resulting in high rates of complete clinical response, which may impact adversely on QOL if radical surgery is subsequently required. Focusing on organ-preservation as the primary goal of treatment rather than overall functional outcomes and QOL for the whole population, may not provide patients with sufficient information for optimal decision-making.

Meta-analysis of the effect of extending the interval after long-course chemoradiotherapy before surgery in locally advanced rectal cancer

BACKGROUND

The current standard of care in locally advanced rectal cancer (LARC) is neoadjuvant long-course chemoradiotherapy (nCRT) followed by total mesorectal excision (TME). Surgery is conventionally performed approximately 6-8 weeks after nCRT. This study aimed to determine the effect on outcomes of extending this interval.

METHODS

A systematic search was performed for studies reporting oncological results that compared the classical interval (less than 8 weeks) from the end of nCRT to TME with a minimum 8-week interval in patients with LARC. The primary endpoint was the rate of pathological complete response (pCR). Secondary endpoints were recurrence-free survival, local recurrence and distant metastasis rates, R0 resection rates, completeness of TME, margin positivity, sphincter preservation, stoma formation, anastomotic leak and other complications. A meta-analysis was performed using the Mantel-Haenszel method.

RESULTS

Twenty-six publications, including four RCTs, with 25 445 patients were identified. A minimum 8-week interval was associated with increased odds of pCR (odds ratio (OR) 1·41, 95 per cent c.i. 1·30 to 1·52; P < 0·001) and tumour downstaging (OR 1·18, 1·05 to 1·32; P = 0·004). R0 resection rates, TME completeness, lymph node yield, sphincter preservation, stoma formation and complication rates were similar between the two groups. The increased rate of pCR translated to reduced distant metastasis (OR 0·71, 0·54 to 0·93; P = 0·01) and overall recurrence (OR 0·76, 0·58 to 0·98; P = 0·04), but not local recurrence (OR 0·83, 0·49 to 1·42; P = 0·50).

CONCLUSION

A minimum 8-week interval from the end of nCRT to TME increases pCR and downstaging rates, and improves recurrence-free survival without compromising surgical morbidity.

Capecitabine versus 5-fluorouracil in neoadjuvant chemoradiotherapy of locally advanced rectal cancer: A meta-analysis

BACKGROUND

The differences in efficacy between capecitabine and 5-fuorouracil (5-FU) in neoadjuvant chemoradiotherapy (CRT) of locally advanced rectal cancer (LARC) are not well recognized. We performed this meta-analysis to analyze the effect of capecitabine and 5-FU on neoadjuvant CRT to more accurately understand the differences between the 2 drugs.

METHODS

MEDLINE, EMBASE, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Database were performed to identify all published studies investigating the efficacy of capecitabine in neoadjuvant CRT of LARC versus 5-FU before August, 2017. Primary endpoint was the odds ratio (OR) for improving pathological complete response (pCR) rate of patients with LARC. Secondary endpoints were the ORs of efficiency for downstaging tumor and increasing R0 resection in patients with LARC. Safety analyses were also performed. The OR was the principal measurement of effect, which was calculated as capecitabine group versus 5-FU group, and was presented as a point estimate with 95% confidence intervals (CIs). All calculations and statistical tests were performed using RevMan 5.3 software.

RESULTS

In all, 2916 patients with LARC enrolled in the 10 studies were divided into capecitabine group (n = 1451) and 5-FU group (n = 1465). The meta-analysis showed that capecitabine improved pCR (OR 1.34, 95% CI 1.10-1.63), and R0 resection rate (OR 1.92, 95% CI 1.10-3.36). There were no statistically significant differences either in overall downstaging rate (OR 1.31, 95% CI 0.79-2.16) or in the tumor downstaging rate (OR 1.24, 95% CI 0.79-1.92), but there was a significant difference of the nodal downstaging rate between the 2 groups (OR 1.68, 95% CI 1.11-2.54). There was no statistically significant difference in sphincter preservation rate between the 2 groups (OR 1.36, 95% CI 0.96-1.92). No obvious safety concerns about mortality and complications were raised in these studies. There were no statistically significant differences in 3-year disease-free-survival (OR 1.29, 95% CI 0.75-2.20), and in grade 3 to 4 acute toxicity during CRT (OR 0.63, 95% CI 0.31-1.30).

CONCLUSIONS

Compared with 5-FU-based neoadjuvant CRT, capecitabine-based neoadjuvant CRT can safely improve pCR, nodal down-staging, ad R0 resection of patients with LARC.

Can Endorectal Ultrasound, MRI, and Mucosa Integrity Accurately Predict the Complete Response for Mid-Low Rectal Cancer After Preoperative Chemoradiation? A Prospective Observational Study from a Single Medical Center

BACKGROUND

Patients with locally advanced rectal cancer could be managed by a watch-and-wait approach if they achieve clinical complete response after preoperative chemoradiotherapy. Mucosal integrity, endorectal ultrasound, and rectal MRI are used to evaluate clinical complete response; however, the accuracy remains questionable. Clinical practice based on those assessment methods needs more data and discussion.

OBJECTIVE

The aim of this prospective study was to evaluate the accuracy of mucosal integrity, endorectal ultrasound, and rectal MRI to predict clinical complete response after chemoradiotherapy.

DESIGN

Endorectal ultrasound and rectal MRI were undertaken 6 to 7 weeks after preoperative chemoradiation therapy. Patients then received radical surgery based on the principles of total mesorectal excision. Preoperative tumor staging achieved by endorectal ultrasound and rectal MRI was compared with postoperative staging by pathologic examination. Sensitivity, specificity, and accuracy of each evaluation method were calculated.

SETTINGS

The study was conducted at a single tertiary care center.

PATIENTS

Patients diagnosed with mid-low rectal cancer by biopsy between May 2014 and December 2016 were enrolled in this study.

RESULTS

A total of 124 patients were enrolled in this study, and postoperative pathology revealed that 20 patients (16.13%) achieved complete response (ypT0N0). The sensitivity of mucosal integrity, endorectal ultrasound, and MRI to predict clinical complete response was 25%. The specificity of mucosal integrity, endorectal ultrasound, and MRI was 94.23%, 93.90%, and 93.27%. The combination of each 2 or all 3 methods did not improve accuracy. Regression analysis showed that none of these methods could predict postoperative ypT0.

LIMITATIONS

The sample size is small, and we did not focus on the follow-up data and cannot compare prognosis data with previous research studies.

CONCLUSIONS

Both single-method and combined mucosal integrity, endorectal ultrasound, and rectal MRI have poor correlation with postoperative pathologic examination. A watch-and-wait approach based on these methods might not be a proper strategy compared with radical surgery after neoadjuvant therapy. See Video Abstract at http://links.lww.com/DCR/A693.

N-myc downstream-regulated gene 1 promotes oxaliplatin-triggered apoptosis in colorectal cancer cells via enhancing the ubiquitination of Bcl-2

N-myc downstream-regulated gene1 (NDRG1) has been identified as a potent tumor suppressor gene. The molecular mechanisms of anti-tumor activity of NDRG1 involve its suppressive effects on a variety of tumorigenic signaling pathways. The purpose of this study was to investigate the role of NDRG1 in the apoptosis of colorectal cancer (CRC) cells. We first collected the clinical data of locally advanced rectal cancer (LARC) patients receiving oxaliplatin-based neoadjuvant chemotherapy in our medical center. Correlation analysis revealed that NDRG1 positively associated with the downstaging rates and prognosis of patients. Then, the effects of over-expression and depletion of NDRG1 gene on apoptosis of colorectal cancer were tested in vitro and in vivo. NDRG1 over-expression promoted apoptosis in colorectal cancer cells whereas depletion of NDRG1 resulted in resistance to oxaliplatin treatment. Furthermore, we observed that Bcl-2, a major anti-apoptotic protein, was regulated by NDRG1 at post-transcriptional level. By binding Protein kinase Cα (PKCα), a classical regulating factor of Bcl-2, NDRG1 enhanced the ubiquitination and degradation of Bcl-2, thus promoting apoptosis in CRC cells. In addition, NDRG1 inhibited tumor growth and promoted apoptosis in mouse xenograft model. In conclusion, NDRG1 promotes oxaliplatin-triggered apoptosis in colorectal cancer. Therefore, colorectal cancer patients can be stratified by the expression level of NDRG1. NDRG1-positive patients may benefit from oxaliplatin-containing chemotherapy regimens whereas those with negative NDRG1 expression should avoid the usage of this cytotoxic drug.

Circulating serum microRNA-345 correlates with unfavorable pathological response to preoperative chemoradiotherapy in locally advanced rectal cancer

Preoperative chemoradiotherapy (pre-CRT) has been represented as the standard treatment for locally advanced rectal cancer (LARC), but large variations of tumor radiation response to CRT have been reported in the clinic. To explore the function of microRNAs as potential therapeutic predictors of pre-CRT pathological response in LARC, we analyzed global miRNA expression in CRT-sensitive and CRT-resistant groups before treatment. MiR-345 was significantly elevated in the CRT-resistant group. Therefore, miR-345 was selected as a candidate for further analysis. We assessed the correlation between the miRNA signatures and the chemoradiotherapeutic response in 20 randomly selected LARC tissue samples (Validation set) and 87 serum samples (Training set) by qRT-PCR. Further, we validated the results in 42 randomly selected LARC serum samples (Validation set). High miR-345 expression was significantly correlated with unfavorable pre-CRT pathological response in tissue and serum. Moreover, low miR-345 levels predicted superior 3-year local recurrence free survival (LRFS). Taken together, circulating serum miR-345 correlates with unfavorable pre-CRT response and poor locoregional control in LARC. It might be a promising biomarker to facilitate patient stratification for personalized treatment.

Optimal Interval to Surgery After Neoadjuvant Chemoradiotherapy in Rectal Cancer: A Systematic Review and Meta-analysis

This study aimed to evaluate the influence of a waiting interval of ≥ 8 weeks between the end of preoperative neoadjuvant chemoradiotherapy (nCRT) and surgery on the outcomes of patients with locally advanced rectal cancer. We conducted a comprehensive literature review of retrospective and prospective studies from PubMed, Embase, and Cochrane Library databases to investigate the length of the preoperative nCRT-surgery waiting interval and outcomes in patients with locally advanced rectal cancer. The primary outcome measure was pathologic complete response (pCR) rate. Secondary outcome measures included overall survival, disease-free survival, operative time, and the incidence of local recurrence, postoperative complications, anastomotic leakage, and sphincter-preserving surgery. Standardized mean differences and risk ratios were calculated. Thirteen studies involving 19,652 patients were included. The meta-analysis demonstrated that pCR was significantly increased in patients with locally advanced rectal cancer and a waiting interval of ≥ 8 weeks between preoperative nCRT and surgery compared to a waiting interval of < 8 weeks, or a waiting interval of > 8 weeks compared to ≤ 8 weeks (risk ratio = 1.25; 95% confidence interval, 1.16-1.35; P < .0001). There were no significant differences in overall survival, disease-free survival, operative time, or incidence of local recurrence, postoperative complications, or sphincter-preserving surgery. This study revealed that performing surgery after a waiting interval of ≥ 8 weeks after the end of preoperative nCRT is safe and efficacious for patients with locally advanced rectal cancer, significantly improving pCR without increasing operative time or incidence of postoperative complications, compared to a waiting interval of ≤ 8 weeks.

A phase II trial of preoperative concurrent chemotherapy and dose escalated intensity modulated radiotherapy (IMRT) for locally advanced rectal cancer

Objectives: To determine the pathological response rates and toxicity and in patients with locally advanced rectal cancer treated with concurrent capecitabine and dose escalated intensity modulated radiotherapy (IMRT)

Methods: Patients with stage II or III adenocarcinoma of the rectum were treated with preoperative concurrent capecitabine and IMRT. Dose of capecitabine was 825mg/m², 5 days a week for 5 weeks. IMRT was used to deliver a dose of 45Gy in 25 fractions (1.8Gy per fraction daily, 5 days a week over 5 weeks) to the regional lymphatics and areas at risk of harbouring microscopic disease. A concomitant synchronous integrated boost (SIB) to the gross tumour with a margin to a total dose of 55Gy in 25 fractions was also delivered in the same period. TME surgery was performed 8 weeks after preoperative therapy. The primary endpoint is pathological complete response rate (pCR) and the secondary endpoint was downstaging rates, Sphincter preservation rates (SPR), disease free survival (DFS) at 2 years and toxicity graded using the CTCAE v3.0.

Results: Twenty three patients were enrolled. Three were not evaluable; one did not complete treatment due to logistic issues and two declined surgery. The remaining 20 patients completed preoperative chemoIMRT followed by TME surgery.

At a median follow-up of 38.2 months (17.5-53.2 months), 90% (18 of 20) patients were alive. The 2 year overall survival and DFS were 90% and 90% respectively. 35%(7/20) of patients had a pCR. 65% (13 of 20) patients had successful downstaging of their rectal tumours. There was no local recurrence. Sphincter preservation rate was 85%. Treatment was well tolerated with only one patient (5%) having Grade 3 radiation proctitis.

Conclusions: Preoperative concurrent capecitabine and dose escalated IMRT is well tolerated and results in high rates of pCR. A randomized trial comparing this regimen with standard 3D conformal chemoradiotherapy is warranted.

Serum miR-143 levels predict the pathological response to neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer

Recently, several circulating miRNAs have been reported as promising, minimally invasive biomarkers for the diagnosis or prediction of the prognosis in various types of cancer. However, the utility of circulating miRNAs as predictive markers of the cancer response to neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer is still unclear. To identify circulating serum miRNAs useful for predicting a pathological good response to nCRT, total 18 serum miRNAs of interest were analyzed by real-time polymerase chain reaction in 94 rectal cancer patients treated with nCRT and surgery. Pathological complete response (pCR; Dworak TRG4) and near-pCR (TRG3) were obtained in 12 (13%) and 9 (9%) patients respectively, and we regarded them as nCRT-responders. Of the 18 serum miRNAs, only the serum level of miR-143 was identified significantly associated with a pathological response to nCRT in 94 patients; the serum miR-143 level was significantly lower in nCRT-responders than in non-responders. A multivariate analysis incorporating other clinicopathological factors showed that only the serum miR-143 level was an independent predictor of a good pathological response. The circulating serum miR-143 level may be a novel, non-invasive predictive marker of a response to nCRT in locally advanced rectal cancer patients.

Comparison of 5-FU-based and Capecitabine-based Neoadjuvant Chemoradiotherapy in Patients With Rectal Cancer: A Meta-analysis

INTRODUCTION

The inconvenience of using infusion therapies resulted in the development of capecitabine (CA), an oral fluoropyrimidine. In this meta-analysis, we evaluated 10 studies that compared the efficacy and safety of an oral CA-based regimen with those of a continuous infusion 5-fluorouracil (5-FU) regimen for neoadjuvant chemoradiotherapy in patients with rectal cancer.

MATERIALS AND METHODS

The databases searched included Medline, Cochrane, EMBASE, and Google Scholar (until August 31, 2016). The primary outcome assessed was the rate of postoperative down-staging of the tumor and pathologic complete response. The secondary outcomes were disease-free survival (DFS) and overall survival (OS).

RESULTS

This meta-analysis (5 retrospective studies, 3 prospective studies, and 2 randomized controlled trials [RCTs]) compared the efficacy of the 5-FU arm (n = 757) to that of the CA arm (n = 719). There was no significant difference in tumor down-staging rate between the 2 regimens (RCTs/prospective studies: odds ratio [OR], 0.88; 95% confidence interval [CI], 0.65-1.20; P = .416; retrospective studies: OR, 0.84; 95% CI, 0.50-1.44; P = .534). There was also no significant difference in pathologic complete response (RCTs/prospective studies: OR, 0.80; 95% CI, 0.52-1.23; P = .304; retrospective studies: OR, 0.73; 95% CI, 0.48-1.12; P = .149), or survival rates (3-year, 5-year DFS, and 5-year OS rate) between the 2 groups. The CA group had a higher number of patients reporting diarrhea and hand-foot syndrome compared with the 5-FU group. The 5-FU group had a higher number of patients reporting mucositis compared with the CA group.

CONCLUSIONS

Our data suggested that oral CA was equivalent to continuous infusion 5-FU in the curative setting of rectal cancer during neoadjuvant chemoradiotherapy.

Chemoradiotherapy and concurrent radiofrequency thermal therapy to treat primary rectal cancer and prediction of treatment responses

The present study aimed to evaluate a previously reported predictive formula of output-limiting symptoms induced by radiofrequency (RF) to determine the efficacy of this neoadjuvant chemoradiation (NACR) and concurrent RF thermal therapy. The present study included 81 consecutive patients with confirmed diagnoses of rectal adenocarcinoma that was localized in the mid-low rectum (up to 12 cm from the anal verge) who received NACR [intensity-modulated radiotherapy (IMRT), 50 Gy/25 fractions, capecitabine 1,700 mg/m2/day for 5 days/week)] with concurrent thermal therapy (Thermotron-RF8, once a week for 5 weeks with 50 min irradiation). Patients with progressive disease (PD) did not receive RF outputs higher than the predicted value. Some patients who were predicted to receive more output in fact received more than the predicted output. In patients who were predicted to receive moderately higher outputs, 37.5% of the patients experienced pathological complete responses, which was the highest rate, while in those who did not receive more than the predicted output, 66.7% of the patients experienced PD, which was the highest rate in the present study. We speculate that RF thermal therapy may offset the chemoradiation effects in some patients. Adding thermal therapy as a multimodality therapy to NACR potentially affects patients with lower predicted outputs and actual observed outputs slightly higher than the predictive value. Our predictive equation for initial energy output, in which output‑limiting symptoms can be used to predict treatment efficacy, consequently, can be used to decide whether to continue this treatment modality.

Radiofrequency thermal treatment with chemoradiotherapy for advanced rectal cancer

We previously reported that patients with a clinical complete response (CR) following radiofrequency thermal treatment exhibit significantly increased body temperature compared with other groups, whereas patients with a clinical partial response or stable disease depended on the absence or presence of output limiting symptoms. The aim of this study was to evaluate the correlation among treatment response, Hidaka radiofrequency (RF) output classification (HROC: termed by us) and changes in body temperature. From December 2011 to January 2014, 51 consecutive rectal cancer cases were included in this study. All patients underwent 5 RF thermal treatments with concurrent chemoradiation. Patients were classified into three groups based on HROC: with ≤9, 10–16, and ≥17 points, calculated as the sum total points of five treatments. Thirty-three patients received surgery 8 weeks after treatment, and among them, 32 resected specimens were evaluated for histological response. Eighteen patients did not undergo surgery, five because of progressive disease (PD) and 13 refused because of permanent colostomy. We demonstrated that good local control (ypCR + CR + CRPD) was observed in 32.7% of cases in this study. Pathological complete response (ypCR) was observed in 15.7% of the total 51 patients and in 24.2% of the 33 patients who underwent surgery. All ypCR cases had ≥10 points in the HROC, but there were no patients with ypCR among those with ≤9 points in the HROC. Standardization of RF thermal treatment was performed safely, and two types of patients were identified: those without or with increased temperatures, who consequently showed no or some benefit, respectively, for similar RF output thermal treatment. We propose that the HROC is beneficial for evaluating the efficacy of RF thermal treatment with chemoradiation for rectal cancer, and the thermoregulation control mechanism in individual patients may be pivotal in predicting the response to RF thermal treatment.

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.

Efficacy of different treatment strategies for stage Ⅱ-Ⅲ rectal cancer

AIM: To compare the efficacy of four treatment strategies for stage Ⅱ-Ⅲ rectal cancer and analyze prognostic factors.

METHODS: A retrospective study was conducted on 230 patients who were pathologically diagnosed with stage Ⅱ-Ⅲ rectal cancer and underwent pelvic intensity modulated radiotherapy and concurrent fluorouracil based chemotherapy between January 2010 and December 2013 at Affiliated Tumor Hospital of Xinjiang Medical University, including 68 cases receiving neoadjuvant chemoradiotherapy combined with surgery (group A), 70 cases receiving postoperative chemoradiation (group B), 51 cases receiving neoadjuvant chemoradiotherapy without surgery (group C), and 41 cases receiving radical chemoradiation (group D). (Neo-) adjuvant radiotherapy was delivered at 50 Gy in 25 fractions, and radical radiotherapy was delivered at 60-66 Gy in 30-33 fractions. Surgical patients were treated by total mesorectal excision. Time interval between radiotherapy and surgery was 4-8 wk.

RESULTS: The follow-up rate was 93.4%, and 144 patients completed the 3-year follow-up. Local recurrence in 3 years was noted in 53 cases, and 44 cases had distant metastasis in the four groups; both the 3-year recurrence rate and distant metastasis rate had no statistical significance among different groups. The 3-year overall survival (OS) and disease-free survival (DFS) rates were statistically different (P = 0.001, 0.004). The rates of OS (86.76%) and DFS (76.27%) in group A were significantly higher than those in the other groups. Complete (R0) tumor resectability was 98.5% in group A and 78.5% in group B. Main toxicities were grade 1-2 adverse events. Multivariate analysis demonstrated that neoadjuvant chemoradiotherapy without surgery (P = 0.002), age (P = 0.021) and circumferential tumor (P = 0.029) were prognostic factors.

CONCLUSION: Neoadjuvant chemoradiotherapy combined with surgery can achieve a higher R0 resection rate and higher OS and DFS than other treatments, representing an effective method for stage Ⅱ-Ⅲ rectal cancer. Neoadjuvant chemoradiotherapy without surgery, age and circumferential tumor are prognostic factors.

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.

A novel strategy of radiofrequency hyperthermia (neothermia) in combination with preoperative chemoradiotherapy for the treatment of advanced rectal cancer: a pilot study

The safety of weekly regional hyperthermia performed with 8 MHz radiofrequency (RF) capacitive heating equipment has been established in rectal cancer. We aimed to standardize hyperthermia treatment for scientific evaluation and for assessing local tumor response to RF hyperthermia in rectal cancer. Forty-nine patients diagnosed with rectal adenocarcinoma were included in the study. All patients received chemoradiation with intensity-modulated radiation therapy 5 days/week (dose, 50 Gy/25 times) concomitant with 5 days/week for five times of capecitabine (1700 mg/m(2) per day) and once a week for five times of 50 min irradiations by an 8 MHz RF capacitive heating device. Thirty-three patients underwent surgery 8 weeks after treatment. Three patients did not undergo surgery because of progressive disease (PD) and 13 refused. Eight (16.3%) patients had a pathological complete response (ypCR) after surgery. Among patients without surgery, 3 (6.1%) had clinical complete response (CR) and 3 (6.1%) had local CR but distant PD (CRPD). Ninety percent of ypCR + CR patients were shown in 6.21 W min(-1) m(-2) /treatment or higher group of average total accumulated irradiation output with 429°C min(-1) m(-2) or higher group of total accumulated thermal output. However, a patient with CRPD was in the higher total accumulated thermal output group. We propose a new quantitative parameter for the hyperthermia and demonstrated that patients can benefit from mild irradiation with mild temperature. Using these parameters, the exact output, optimal thermal treatment, and contraindications or indications of this modality could be determined in a multi-institutional, future study.

Trial Watch: Immunogenic cell death inducers for anticancer chemotherapy

The term "immunogenic cell death" (ICD) is now employed to indicate a functionally peculiar form of apoptosis that is sufficient for immunocompetent hosts to mount an adaptive immune response against dead cell-associated antigens. Several drugs have been ascribed with the ability to provoke ICD when employed as standalone therapeutic interventions. These include various chemotherapeutics routinely employed in the clinic (e.g., doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin) as well as some anticancer agents that are still under preclinical or clinical development (e.g., some microtubular inhibitors of the epothilone family). In addition, a few drugs are able to convert otherwise non-immunogenic instances of cell death into bona fide ICD, and may therefore be employed as chemotherapeutic adjuvants within combinatorial regimens. This is the case of cardiac glycosides, like digoxin and digitoxin, and zoledronic acid. Here, we discuss recent developments on anticancer chemotherapy based on ICD inducers.

Lymph node count after preoperative radiotherapy is an independently prognostic factor for pathologically lymph node-negative patients with rectal cancer

Recent studies indicated that preoperative radiotherapy significantly reduces the lymph nodes (LNs) harvest from patients with rectal cancer. This may weaken the prognostic value of current standard of LNs retrieval (≥12 LNs). This study investigates the prognostic impact of the LN counts on pathologically LN-negative (ypN0) after preoperative radiotherapy for patients with rectal cancer.Surveillance, Epidemiology and End Results (SEER) registered nonmetastatic rectal cancer patients diagnosed between 1998 and 2005 were included in this study. Optimal cutoff value for number of LNs retrieved was determined by X-tile program. Log-rank tests were adopted to compare the rectal cause specific survival (RCSS) for ypN0 patients using separated cutoff value of LN counting from 2 to 20. Correlation between LN count and tumor regression was investigated in an additional 221 patients from Fudan University Shanghai Cancer Center (FUSCC).The results showed that there were fewer number of LNs examined in patients with preoperative radiotherapy than those without (8.9 vs 10.9, P < 0.001). X-tile program identified the difference in survival was most significant (maximum of χ log-rank values) for the number 4. And 5-year RCSS increased accordingly with the cutoff values ranging from 4 to 15, which were confirmed as optimal cutoff and validated as independent prognostic factors in multivariate regression analysis (χ = 50.65, P < 0.001). Patients in FUSCC set were found to have fewer LNs retrieval in group of good tumor regression than in that of poor one (P = 0.01).These results confirmed the reduced number of LN retrieval in patients with rectal cancer treated with preop-RT. LN count is still an independently prognostic factor for ypN0 rectal cancer.

Trial Watch: Radioimmunotherapy for oncological indications

During the past two decades, it has become increasingly clear that the antineoplastic effects of radiation therapy do not simply reflect the ability of X-, β- and γ-rays to damage transformed cells and directly cause their permanent proliferative arrest or demise, but also involve cancer cell-extrinsic mechanisms. Indeed, among other activities, radiotherapy has been shown to favor the establishment of tumor-specific immune responses that operate systemically, underpinning the so-called 'out-of-field' or 'abscopal' effect. Thus, ionizing rays appear to elicit immunogenic cell death, a functionally peculiar variant of apoptosis associated with the emission of a particularly immunostimulatory combination of damage-associated molecular patterns. In line with this notion, radiation therapy fosters, and thus exacerbates, the antineoplastic effects of various treatment modalities, including surgery, chemotherapy and various immunotherapeutic agents. Here, we summarize recent advances in the use of ionizing rays as a means to induce or potentiate therapeutically relevant anticancer immune responses. In addition, we present clinical trials initiated during the past 12 months to test the actual benefit of radioimmunotherapy in cancer patients.

BCL2 protein signalling determines acute responses to neoadjuvant chemoradiotherapy in rectal cancer

In locally advanced rectal cancer, neoadjuvant chemoradiotherapy is performed prior to surgery to downstage the tumour. Thirty to 40 % of patients do not respond. Defects in apoptotic machinery lead to therapy resistance; however, to date, no study quantitatively assessed whether B cell lymphoma 2 (BCL2)-dependent regulation of mitochondrial apoptosis, effector caspase activation downstream of mitochondria or a combination of both predicts patient responses. In a cohort of 20 rectal cancer patients, we performed protein profiling of tumour tissue and employed validated ordinary differential equation-based systems models of apoptosis signalling to calculate the ability of cancer cells to undergo apoptosis. Model outputs were compared to clinical responses. Systems modelling of BCL2-signalling predicted patients in the poor response group (p = 0.0049). Systems modelling also demonstrated that rectal cancers depended on BCL2 rather than B cell lymphoma-extra large (BCL(X)L) or myeloid cell leukemia 1 (MCL1) for survival, suggesting that poor responders may benefit from therapy with selective BCL2 antagonists. Dynamic modelling of effector caspase activation could not stratify patients with poor response and did not further improve predictive power. We deliver a powerful patient stratification tool identifying patients who will likely not benefit from neoadjuvant chemoradiotherapy and should be prioritised for surgical resection or treatment with BCL2 antagonists.

KEY MESSAGES

Modelling BCL2-family proteins identifies patients unresponsive to therapy. Caspase activation downstream of mitochondria cannot identify these patients. Rectal tumours of poor responders are BCL2- but not BCL-XL-dependent. DR_MOMP allows clinicians to identify patients who would not benefit from therapy. DR_MOMP is also a useful patient stratification tool for BCL2 antagonists.