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

A panel of tumor biomarkers to predict complete pathological response to neo-adjuvant treatment in Locally Advanced Rectal Cancer

Pathological complete response after neoadjuvant chemoradiotherapy in locally advanced rectal cancer patients is related to a favorable prognosis. The identification of early biomarkers predictive of pathological complete response would help optimize the multimodality management of the patients. A panel of 11 tumor-related proteins was investigated by immunohistochemistry in the pretreatment biopsy of a group of locally advanced rectal cancer patients to identify early biomarkers of pathological complete response to neoadjuvant chemoradiotherapy. A mono-institutional retrospective cohort of 95 stage II/III locally advanced rectal cancer patients treated with neoadjuvant chemoradiotherapy and surgery was selected based on clinical–pathological characteristics and the availability of a pretreatment tumor biopsy. Eleven selected protein marker expression (MLH1, GLUT1, Ki67, CA-IX, CXCR4, COX2, CXCL12, HIF1α, VEGF, CD44, and RAD51) was investigated. The optimal cutoff values were calculated by receiver operating characteristic curve analysis. Classification and regression tree analysis was performed to investigate the biomarker interaction. Patients presenting either Ki-67 or HIF1α or RAD51 below the cutoff value, or CXCR4 or COX2 above the cutoff value, were more likely to get a pathological complete response. Classification and regression tree analysis identified three groups of patients resulting from the combination of Ki-67 and CXCR4 expression. Patients with high expression of Ki-67 had the lowest chance to get a pathological complete response (18%), as compared to patients with low expression of both Ki-67 and CXCR4 (29%), and patients with low Ki-67 and high CXCR4 expression (70%). Pretreatment Ki-67, CXCR4, COX2, HIF1α, and RAD51 in tumor biopsies are associated with pathological complete response after neoadjuvant chemoradiotherapy in locally advanced rectal cancer. A combined evaluation of Ki-67 and CXCR4 would increase their predictive potential. If validated, their optimal cutoff could be used to select patients for a tailored multimodality treatment.

Computertomography-Based Prediction of Complete Response Following Neoadjuvant Chemoradiotherapy of Locally Advanced Rectal Cancer

Therapeutic strategies for patients with locally advanced rectal cancer (LARC) who are achieving a pathological complete response (pCR) after neoadjuvant radio-chemotherapy (neoCRT) are being increasingly investigated. Recent trials challenge the current standard therapy of total mesorectal excision (TME). For some patients, the treatment strategy of “watch-and-wait” seems a preferable procedure. The key factor in determining individual treatment strategies following neoCRT is the precise evaluation of the tumor response. Contrast-enhanced computer tomography (ceCT) has proven its ability to discriminate benign and malign lesions in multiple cancers. In this study, we retrospectively analyzed the ceCT based density of LARC in 30 patients, undergoing neoCRT followed by TME. We compared the tumors´ pre- and post-neoCRT density and correlated the results to the amount of residual vital tumor cells in the resected tissue. Overall, the density decreased after neoCRT, with the highest decrease in patients achieving pCR. Densitometry demonstrated a specificity of 88% and sensitivity of 68% in predicting pCR. Thus, we claim that ceCT based densitometry is a useful tool in identifying patients with LARC who may benefit from a “watch-and-wait” strategy and suggest further prospective studies.

Time interval between neoadjuvant radio-chemotherapy and surgery in rectal cancer: is the long interval correct for all patients?

BACKGROUND

Optimal time between neoadjuvant radio-chemotherapy period and surgery remains controversial in patients with rectal cancer: an increasing number of studies show results in favour of a long interval.

METHODS

We conducted a retrospective analysis of the cases of low-middle rectal adenocarcinoma undergoing neoadjuvant RT-CT and surgery: the primary endpoint was the complete pathological response rate and the secondary endpoint the rate of complications. We analysed cases from 1/01/2003 to 31/12/2018 divided in two periods: from 2003 to 2010 (23 pts) and from 2011 to 2018 (23 pts). The two periods were characterised by two different surgical teams which use different time intervals (≤vs>8 weeks).

RESULTS

The pCR rate is 21.7% in both groups; as regards the complications, the difference between the two groups is in grade IIIb: 8.7% in the first group and 17.4% in the second group (p 0.66).

CONCLUSIONS

Although our study is based on a small number of patients, it shows the same rate of pCR with respect to two different time intervals; this suggests the need for studies based on the division of patients into subgroups and the evaluation of different time intervals in order to reach the best oncological outcomes.

Predictive Factors for Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer

Background:

An accurate assessment of potential pathologic complete response(pCR) following neoadjuvant chemoradiotherapy(NCRT) is important for the appropriate treatment of rectal cancer. However, the factors that predict the response to neoadjuvant chemoradiotherapy have not been well defined. Therefore, this study analyzed the predictive factors on the development of pCR after neoadjuvant chemoradiation for rectal cancer.

Methods:

From January 2008 to January 2018, a total of 432 consecutive patients from a single institution patients who underwent a long-course neoadjuvant chemoradiotherapy were reviewed in this study. The clinicopathological features were analyzed to identify predictive factors for pathologic complete response in rectal cancer after neoadjuvant chemoradiation.

Results:

The rate of pathologic complete response in rectal cancer after neoadjuvant chemoradiation was 20.8%, patients were divided into the pCR and non-pCR groups. The two groups were well balanced in terms of age, gender, body mass index, ASA score, tumor stage, tumor differentiation, tumor location, surgical procedure, chemotherapy regimen and radiation dose. The multivariate analysis revealed that a pretreatment carcinoembryonic antigen (CEA) level of ≤5 ng/mL and an interval of ≥8 weeks between the completion of chemoradiation and surgical resection were independent risk factors of an increased rate of pCR.

Conclusions:

Pretreatment carcinoembryonic antigen (CEA) level of ≤5 ng/mL and an interval of ≥8 weeks between the completion of chemoradiation and surgical resection are predictive factors for pathologic complete response in rectal cancer after neoadjuvant chemoradiation. Using these predictive factors, we can predict the prognosis of patients and develop adaptive treatment strategies. A wait-and-see policy might be possible in highly selective cases.

Assessment of the non-surgical treatment of patients with rectal cancer who underwent neoadjuvant treatment with chemotherapy and radiotherapy at the oncology department

Objective To describe the partial results of a study in patients with rectal cancer who underwent neoadjuvant treatment with chemotherapy and radiotherapy regarding the rate of complete clinical response, disease-free survival, anorectal function, and quality of life.

Material and methods This was a prospective study from June 2015 to June 2018, in patients with low- or mid-rectum adenocarcinoma and clinical stage II or III, treated with radiotherapy and chemotherapy (IMRT 54 Gy for six weeks) concomitant with 5-fluorouracil (5-FU) 380 mg/m2 and folinic acid (LV) 20 mg/m2 for five days in the first and fifth weeks and two cycles after radiotherapy (5-FU 400 mg/m2 and LV 20 mg/m2) every 28 days. After the treatment, clinical examination, rectosigmoidoscopy, pelvic magnetic resonance imaging, chest and upper abdomen computed tomography, and CEA testing were performed. Resection surgery was performed in those with incomplete clinical response (iCR). Those with complete clinical response (cCR) are under observation (wait-and-see policy). Manometry and scintigraphic function and quality of life scales were collected before treatment and at 30 and 90 days after the end of treatment.

Results As of June 2018, 11 patients were recruited. One was excluded from the analysis for presenting severe toxicity, suggestive of dihydropyrimidine dehydrogenase (DPD) deficiency, after the first chemotherapy cycle. All others completed the treatment. Two patients presented toxicity grade 3/4 related to chemotherapy and had their doses reduced. Seven patients (70%) presented iRC; three underwent rectosigmoidectomy, and the anatomopathological evaluation indicated complete pathological response in two cases (28.5%). Three (30%) presented cCR and did not present evidence of disease after a mean follow-up of 19 months. Patients presented improvement of anorectal function and quality of life.

Conclusions Advances in the neoadjuvant treatment of rectal tumors contributed to better rates of complete pathological responses. New paradigms promote an increase in the complete clinical response rates, which would allow organ preservation and consequent reduction of surgical morbidity.

Neoadjuvant Therapy and Surgery in Rectal Adenocarcinoma: Analysis of Patients with Complete Tumor Remission

Introduction: the standard treatment for locally advanced extra-peritoneal rectal adenocarcinoma, consists of neoadjuvant treatment with radiotherapy and chemotherapy followed by total mesorectal excision.

Objective: evaluate, retrospectively, the patients submitted to neoadjuvant therapy and surgery that presents with total remission of the lesion in the anatomopathological examination.

Methods: between 2000 and 2010, 212 patients underwent surgery at the Coloproctology Unit at DMAD at FCM–UNICAMP. They were grouped as: rectosigmoidectomy and colorectal anastomosis (n = 54), rectosigmoidectomy with coloanal anastomosis (n = 41), 114 abdominoperineal resection of the rectum (n = 114) and other (n = 3).

Results: thirty (14.2%) patients (mean age 57.6 years; 60% males) showed complete remission of the rectal lesion. 4 (13.3%) had compromised lymph nodes and/or lymphatic invasion

At follow-up (mean 51.9 months), 4 (13.3%) presented with local recurrence (one patient) or distant metastases (two patients had liver metastasis, one had liver and lung, and one had bone metastasis). The mean survival was 86.7%.

Conclusion: patients with a complete tumor response show ed an increased survival rate, however, the same patients without evidence of residual tumors could develop local recurrence or distant metastases on a later follow-up.

Red Blood Cell Distribution Width (RDW) Correlates to the Anatomical Location of Colorectal Cancer. Implications for Clinical Use

PURPOSE

The pathological, clinical, and therapeutic features of colorectal cancer (CRC) depend on its anatomical localization. We investigated possible associations between the red blood cell distribution width (RDW) and CRC localization.

METHODS

Two-hundred eighty-eight consecutive patients with CRC were retrospectively studied. Demographic, clinical, pathological and laboratory data were retrieved from clinical records and reports.

RESULTS

Median RDW values were significantly higher in patients with right-sided CRC when compared to those with CRC in other localizations (16.2, IQR: 14.5-20.0 vs 13.8, IQR: 13.0-16.1, p < 0.0001). Anisocytosis was statistically associated to haemoglobin (Hb), mean haemoglobin concentration (MHC), and mean corpuscular volume (MCV) values in all the patient groups examined. A cut-off value of 14.3% was associated with right-sided localization with sensitivity and specificity of 76.3% and 64.2%, respectively (AUC 0.71).

CONCLUSION

Median RDW values were significantly higher in right-sided CRC when compared to other tumour locations, and may represent an additional marker for differential diagnosis.

Predictive factors associated with complete pathological response after neoadjuvant treatment for rectal cancer

PURPOSE

A proportion of 10 to 30% of patients treated by chemoradiotherapy followed by total mesorectal excision surgery for a locally advanced rectal cancer can achieve a complete pathological response. We aimed to identify predictive factors associated with complete pathological response or no response and to assess the impact of each response on survival rates.

PATIENTS AND METHODS

Patients treated with long course chemoradiotherapy for locally advanced and/or node positive rectal cancer from 2010 to 2016 were retrospectively reviewed. Statistical analysis was carried out to determine predictors of tumor regression and treatment outcomes.

RESULTS

Records were available on 70 patients. In the univariate analysis, clinical factors associated with complete tumor response were tumor mobility in digital rectal examination (P=0.047), a limited parietal invasion (P=0.001), clinically negative lymph node (P<0.001) and a circumferential extent greater than 50% (P=0.001). On the other hand, a T4 classification and an endoscopic tumor size greater than 6cm were associated with no response to treatment (P=0.049 and P=0.017 respectively). On multivariate analysis, T2 clinical classification and N0 statement before treatment were independent predictive factors of pathologic complete response (P<0.001 and P=0.001) and a delayed surgery after 12 weeks was associated with no response to treatment (P=0.001).

CONCLUSION

The identification of predictive factors of histological response may help clinicians to predict the prognosis and to propose organ preservation for good responders.

Pretreatment Albumin-to-Fibrinogen Ratio Independently Predicts Chemotherapy Response and Prognosis in Patients with Locally Advanced Rectal Cancer Undergoing Total Mesorectal Excision After Neoadjuvant Chemoradiotherapy

Background

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery of total mesorectal excision (TME) is currently accepted as the standard treatment for locally advanced rectal cancer (LARC). This study aimed to investigate the potential prognostic factors, including the albumin-to-fibrinogen ratio (AFR) for LARC patients.

Methods

We retrospectively recruited LARC patients (cT3-4 and/or cN1-2) who underwent nCRT followed by TME between January 2011 and January 2015. The cut-off value of pretreatment AFR for overall survival (OS) was determined by the receiver operating characteristic (ROC) curve. The potential predictive factors for prognosis in the LARC patients were assessed by the univariate and multivariate Cox’s proportional hazard regression and Kaplan–Meier curve analyses.

Results

AFR was a significant predictor for OS with a cut-off value of 8.65 and an AUC of 0.882 (P<0.001). The pretreatment AFR level was the only independent risk factor for pathologic response to nCRT (HR: 2.44, 95% CI: 1.43–4.17, P=0.003), 5-year OS (HR: 3.31, 95% CI: 1.51–6.77, P=0.005) and disease-free survival (DFS) (HR: 2.73, 95% CI: 1.34–5.47, P=0.007) in LARC patients. A low pretreatment AFR level was significantly associated with a poor 5-year OS and DFS by the Log rank test (P=0.003 and 0.006, respectively).

Conclusion

Pretreatment AFR level was an independent prognostic factor in LARC patients undergoing TME after nCRT.

Comprehensive Analysis of DNA Methylation and Prediction of Response to NeoadjuvantTherapy in Locally Advanced Rectal Cancer

The treatment for locally advanced rectal carcinomas (LARC) is based on neoadjuvant chemoradiotherapy (nCRT) and surgery, which results in pathological complete response (pCR) in up to 30% of patients. Since epigenetic changes may influence response to therapy, we aimed to identify DNA methylation markers predictive of pCR in LARC patients treated with nCRT. We used high-throughput DNA methylation analysis of 32 treatment-naïve LARC biopsies and five normal rectal tissues to explore the predictive value of differentially methylated (DM) CpGs. External validation was carried out with The Cancer Genome Atlas-Rectal Adenocarcinoma (TCGA-READ 99 cases). A classifier based on three-CpGs DM (linked to OBSL1, GPR1, and INSIG1 genes) was able to discriminate pCR from incomplete responders with high sensitivity and specificity. The methylation levels of the selected CpGs confirmed the predictive value of our classifier in 77 LARCs evaluated by bisulfite pyrosequencing. Evaluation of external datasets (TCGA-READ, GSE81006, GSE75546, and GSE39958) reproduced our results. As the three CpGs were mapped near to regulatory elements, we performed an integrative analysis in regions associated with predicted cis-regulatory elements. A positive and inverse correlation between DNA methylation and gene expression was found in two CpGs. We propose a novel predictive tool based on three CpGs potentially useful for pretreatment screening of LARC patients and guide the selection of treatment modality.

Verification of the Optimal Interval Before Esophagectomy After Preoperative Neoadjuvant Chemoradiotherapy for Locally Advanced Thoracic Esophageal Cancer

BACKGROUND

The interval between preoperative chemoradiotherapy and surgery reportedly affects perioperative outcomes and survival; however, the optimal interval in esophageal cancer patients remains uncertain.

OBJECTIVE

Our aim was to determine whether a prolonged interval between preoperative neoadjuvant chemoradiotherapy (NACRT) and esophagectomy affects the outcomes of esophageal cancer patients.

METHODS

A total of 131 patients with esophageal cancer received curative surgery following NACRT at Akita University Hospital between 2009 and 2017. We divided these patients into two groups based on the median interval from NACRT to esophagectomy, and compared the rates of pathological complete response (pCR), surgical outcomes, and survival.

RESULTS

The median interval from NACRT to esophagectomy was 39 days (range 21-95). Of the 131 patients, 70 (53%) received esophagectomy after 39 days or more from completion of NACRT. There were no significant differences in the clinicopathological features, including pCR rates, between the two groups. Prolongation of the interval from NACRT to esophagectomy was significantly associated with an increased rate of anastomotic leakage and recurrent laryngeal nerve palsy (p = 0.0225 and p = 0.0022, respectively); however, no association with overall survival was detected.

CONCLUSIONS

A prolonged interval between NACRT and esophagectomy had no impact on pCR rates or survival. However, delaying esophagectomy may increase the likelihood of surgical complications such as anastomotic leakage and recurrent laryngeal nerve palsy.

Impact of KRAS status on tumor response and survival after neoadjuvant treatment of locally advanced rectal cancer

BACKGROUND

Mutation of the KRAS oncogene (mKRAS) in colorectal cancer has been associated with aggressive tumor biology, resistance to epidermal growth factor inhibitors, and decreased overall survival (OS). The aim of the current study was to analyze the association of mKRAS with pathologic complete response (pCR) and neoadjuvant rectal (NAR) score, and its impact on the survival of patients with locally advanced rectal cancer who were managed with multimodality therapy.

METHODS

The National Cancer Database was queried for stage II-III rectal cancer patients with a known KRAS status who underwent neoadjuvant chemoradiation therapy (nCRT) and proctectomy between 2004 and 2015.

RESULTS

In total, 1886 patients were identified; 12% had pCR and 36% had mKRAS. Patients with mKRAS were more likely to have advanced pathologic T stage, tumor deposits, perineural invasion, and elevated carcinoembryonic antigen levels (all p ≤ .05). After adjustment for available confounders, mKRAS status was not associated with pCR or NAR score. In multivariable analysis, patients with pCR and lower NAR score had better OS, whereas mKRAS was independently associated with a worse prognosis.

CONCLUSION

In this cohort of locally advanced rectal cancer patients who underwent proctectomy after nCRT, mKRAS was not associated with lower pCR rates or NAR scores; however, these patients experienced worse survival.

Timing to achieve the highest rate of pCR after preoperative radiochemotherapy in rectal cancer: a pooled analysis of 3085 patients from 7 randomized trials

PURPOSE

Optimal timing of surgery after neoadjuvant chemoradiotherapy (Nad-CRT) is still controversial in locally advanced rectal cancer (LARC). The primary goal of this study was to determine the best surgical interval (SI) to achieve the highest rate of pathological complete response (pCR) and secondly to evaluate the effect on survival outcomes according to the SI.

PATIENTS AND METHODS

Patients data were extracted from the international randomized trials: Accord12/0405, EORTC22921, FFCD9203, CAO/ARO/AIO-94, CAO-ARO-AIO-04, INTERACT and TROG01.04. Inclusion criteria were: age≥ 18, cT3-T4 and cN0-2, no clinical evidence of distant metastasis at diagnosis, Nad-CRT followed by surgery. Pearson's Chi-squared test with Yates' continuity correction for categorical variables, the Mann-Whitney test for continuous variables, Mann-Kendall test, Kaplan-Meier curves with log-rank test, univariate and multivariate logistic regression model was used for data analysis.

RESULTS

3085 patients met the inclusion criteria. Overall, the pCR rate was 14% at a median SI of 6 weeks (range 1-31). The cumulative pCR rate increased significantly when SI lengthened, with 95% of pCR events within 10 weeks from Nad-CRT. At univariate and multivariate logistic regression analysis, lengthening of SI (p< 0.01), radiotherapy dose (p< 0.01), and the addition of oxaliplatin to Nad-CRT (p< 0.01) had a favorable impact on pCR. Furthermore, lengthening of SI was not impact on local recurrences, distance metastases, and overall survival.

CONCLUSION

This pooled analysis suggests that the best time to achieve pCR in LARC is at 10 weeks, considering that the lengthening of SI is not detrimental concerning survival outcomes.

Predictive factors of complete pathological response in patients with locally advanced rectal cancer

PURPOSE

Patients with locally advanced rectal cancer who achieve pathologic complete response (pCR) following neoadjuvant therapy have better long-term outcomes and could be spared from the perioperative and long-term morbidity of rectal resection. The aim of this study was to identify factors that predict the ability to achieve pCR at completion of conventional neoadjuvant therapy, therefore determining their suitability for non-surgical management.

METHODS

A retrospective analysis was performed on data obtained from a prospectively maintained colorectal neoplasia database. Patients treated for biopsy-proven primary rectal adenocarcinoma between January 1, 2010, and February 28, 2018, who received neoadjuvant radiotherapy or chemoradiotherapy and had undergone surgical resection, were included in this study. Five-year oncologic outcome data was also obtained for 144 patients. Clinicopathological tumour characteristics and treatment regimens were analysed for correlation to clinical outcome.

RESULTS

Three hundred fifty-four patients met inclusion criteria for this study. We identified significant differences between patients achieving a pCR and those that did not for tumour type (adenocarcinoma vs. mucinous/signet ring; p = 0.008), pre-treatment serum CEA level (</≥ 2.5 μg/L; p = 0.003), neoadjuvant therapy type (short-course radiotherapy and long-course chemoradiotherapy; p = 0.008) and preoperative lymph node status (node-negative versus node-positive disease; p = 0.031). Additionally, this is the first report to our knowledge to identify a significant correlation with pCR and the degree of tumour fixity (mobile vs. fixed/tethered; p = 0.038).

CONCLUSIONS

This retrospective analysis identified factors that significantly impact a patients' ability to achieve a pCR, which may prove useful for prospectively selecting patients suitable for non-surgical management of disease.

Consolidation chemotherapy may improve pathological complete response for locally advanced rectal cancer after neoadjuvant chemoradiotherapy: a retrospective study

BACKGROUND

Patients with locally advanced rectal cancer (LARC) have an improved prognosis if achieved a pathological complete response (pCR) on account of neoadjuvant chemoradiation therapy (nCRT). However, the proportion of patients achieving pCR is only 8-24%. The purpose of this study was to explore whether the addition of consolidation chemotherapy to nCRT could improve pCR rate in patients with LARC.

MATERIALS AND METHODS

The subjects were 144 individuals with clinical stage II (T3-4, N0) or III (any T, N1-2) LARC who had received neoadjuvant CRT followed by total mesorectal excision (TME). Eighty-three patients in the consolidation chemotherapy group received two cycles XELOX between CRT and TME, while 61 patients in the standard treatment group without consolidation chemotherapy. The pCR (ypT0N0), tumor downstaging (ypT0-2N0) after TME and adverse events (AEs) during and post treatment were compared between the treatment groups using multivariable logistic regression analysis. To adjust the unbalanced variables for the primary endpoint, logistic regression analysis and stratified analysis were performed.

RESULTS

The consolidation chemotherapy group improved pCR rate (19.3% vs 4.9%, p = 0.01) and tumor downstaging rate (45.8% vs 24.6%, p = 0.009) compared to the standard treatment group. After adjustment for clinical tumor stage, clinical nodal stage and time interval to surgery, patients with consolidation chemotherapy were more likely to reach pCR (adjusted odds ratio 4.91, 95% CI [1.01-23.79], p = 0.048). AEs during and post treatment in the two groups were 54.1% vs 49.3% (p = 0.57), respectively. In addition, the incidence of any grade 1-2 AEs in the two groups was 93.4% vs 95.1% (p = 0.93), while the incidence of grade 3 AEs was 1.6% versus 2.4% (p = 0.74), respectively. No grade 4 AEs occurred in two groups.

CONCLUSIONS

The addition of neoadjuvant consolidation chemotherapy after CRT significantly increased the pCR rate and did not increase the AEs during and post treatment and in patients with LARC.

Connection and distinction of tumor regression grading systems of gastrointestinal cancer

OBJECTIVES

As the neoadjuvant therapy has been successfully introduced in the treatment of gastrointestinal malignancies, the evaluation of therapeutic effectiveness is becoming increasingly important. Tumor-node-metastasis system has been widely applied. However, this system is mainly based on the location of residual tumor, but does not consider the amount of residual tumor. Tumor regression grading system, a quantitative method to assess the reaction of tumor to neoadjuvant treatment, could be used as a supplement to tumor-node-metastasis system and provide additional information on prognosis. To date, numerous gastrointestinal grading systems have been used in esophageal/esophagogastric junction carcinoma, gastric adenocarcinoma, colorectal cancer, and most of them were considered to associate with clinical outcomes.

MATERIALS AND METHODS

In this review, firstly, we expounded the importance of tumor regression grading systems, and summarized the histopathological changes after neoadjuvant therapy. Secondly, we introduced some commonly used gastrointestinal systems, as well as the relationships and nuance. Finally, we discussed pivotal issues about these systems. In this part, we explained the calculation methods based on grid points and square measures, discussed several factors leading to observer bias, containing the slice number and the grading tier number, and analyzed the factors that might affect clinical significance, covering anatomical location, the selection of survival index, and the tumor type.

RESULTS

Tumor regression grade systems could be divided into two main classifications, the relative amount of fibrosis and residual tumor, and the proportion of residual tumor in the tumor bed. However, the definitions of these systems were still need to be improved.

CONCLUSIONS

The tumor regression grading system is useful in evaluating tumor response to neoadjuvant therapy, but more work is needed to refine and unify the system.

Nonsurgical Management of Rectal Cancer

Neoadjuvant chemoradiotherapy followed by surgical resection is the standard of care for locally advanced rectal adenocarcinoma. Up to one third of patients achieve pathologic complete response (CR) with neoadjuvant therapy. Promising disease-free and overall survival outcomes have been reported in patients who achieve clinical CR after neoadjuvant therapy without surgical resection. Furthermore, patients who have local recurrence have acceptable disease control outcomes with salvage resection. With consideration of morbidities associated with surgical resection and similar clinical outcomes, interest in nonsurgical management of low rectal cancers has emerged. Randomized clinical trials are being conducted to evaluate a nonsurgical approach in rectal cancer. Lack of consensus on the definition of clinical CR, molecular biomarkers, and standardized nonsurgical management protocols is a significant barrier for routine clinical implementation of a nonsurgical management approach. This article aims to provide a concise review of the clinical experience and practical approach to the nonsurgical management of locoregional rectal adenocarcinoma.

Prognostic significance of early complete response in patients with locally advanced rectal cancer undergoing preoperative chemoradiotherapy: Multicentric study of Turkish Society for Radiation Oncology Group (TROD)

BACKGROUND/AIMS

To assess the effect of various parameters on the oncologic outcomes, including the time interval between therapy and surgery (S) in locally advanced rectal cancer (LARC) patients receiving preoperative chemoradiotherapy (CRT).

MATERIALS AND METHODS

The data of 914 LARC patients who received preoperative CRT between 1994 and 2015 were collected retrospectively. Patients received 45-50.4 Gy RT with 5FU based chemotherapy (CT). They all underwent radical resection followed by maintenance CT. Clinical and pathologic variables were compared between the pCR and no-pCR groups. Survival was estimated by the Kaplan-Meier method and Cox proportional hazard model was used in multivariate analysis.

RESULTS

After median follow-up of 60.5 (range=12-297.6) months, median overall survival (OS) was 58.75 months and disease-free survival (DFS) 53.32 months. pCR was observed in 18.9% of all cases. pCR, lymphovascular invasion and metastatic lymph node ratio (mLNR) were significantly associated with OS and DFS on multivariate analysis. The 5-year OS and DFS rates were better in pCR group (95.3% vs 80.7% for OS, p<0.0001 and 87.4% vs 71% for DFS, p<0.0001). pCR patients with 4-8 weeks interval had lower rates of distant metastasis (9% vs 20%, p=0.01) and any recurrences (13.6% vs 29.6%, p=0.001) than the remaining. Both OS and DFS were better in favor of pCR achieved at 4-8 week interval time (p<0.0001 for each).

CONCLUSION

pCR after preoperative CRT in LARC correlated with better oncologic outcome. The best OS and DFS durations were achieved in patients who experienced pCR after 4-8-weeks interval before surgery.

Transcatheter rectal arterial chemoembolization with oxaliplatin plus S-1 concurrent chemoradiotherapy can improve the pathological remission rate in locally advanced rectal cancer: a comparative study

Background

To explore the efficacy and safety of Transcatheter rectal arterial chemoembolization with oxaliplatin and S-1 concurrent chemoradiotherapy as neoadjuvant therapy for locally advanced rectal cancer.

Methods

This s a prospective, monocentric, non-randomized clinical study, a total of 95 patients were enrolled and assigned to two groups: an investigational group (n = 50) receiving transcatheter rectal arterial chemoembolization (TRACE) with oxaliplatin and preoperative radiotherapy plus S-1 concurrent chemotherapy (NATRACE-CRT), followed by surgery, a control group (n = 45) receiving standard fluorouracil-based combined modality treatment, consisting of preoperative radiotherapy plus capecitabine based chemotherapy (NA-CRT), followed by surgery. The primary endpoint was postoperative pathological regression rate which evaluated by tumor regression grade (TRG) according to the 7th edition of the American Joint Committee on Cancer (AJCC) standard, and the secondary endpoints included objective response rate (ORR) and toxicity, as well as surgical complications, and postoperative tumor downstaging.

Results

Compared with NA-CRT group (17.78% (95% confidence interval (CI): 6.2–29.4)), the TRG0 was 30% (95% CI 16.8–43.2) in the NATRACE-CRT group (P = 0.231). The TRG0 + 1 rate was 60% (95% CI: 45.9–74.1) and 33.33% (95% CI: 19–47.7) in NATRACE-CRT group and NA-CRT group, respectively (P = 0.013). The ORR of the NATRACE-CRT group was 84% and that of the NA-CRT group was 66.67% (p = 0.058). Incidence of preoperative toxic side effects and surgical complications was similar between the two groups.

Conclusion

TRACE with oxaliplatin plus concurrent S-1 chemoradiotherapy as a neoadjuvant therapy provided better pathological remission rate versus standard treatment with a similar safety profile.

Trial registration

NCT03601156.

Effect of aspirin use on neoadjuvant chemoradiotherapy for rectal cancer: a meta-analysis with trial sequential analysis

BACKGROUND

Numerous studies have reported the preventive and protective effects of aspirin in patients with rectal cancer. However, it is not clear whether aspirin can be used as an assistance drug in preoperative neoadjuvant chemoradiotherapy. Therefore, this study will explore the efficacy of aspirin as an adjuvant agent in rectal cancer neoadjuvant chemoradiotherapy.

METHODS

A literature search was performed using the electronic platforms to obtain relevant research studies published up to Jan 2020. The search was limited to papers published in English or Chinese language. Confidence intervals of research endpoints in each study were extracted and merged. The meta-analysis was performed using Stata12.0 software. Furthermore, we performed trial sequential analysis (TSA) to evaluate the robustness of our findings and to obtain a more conservative estimation.

RESULTS

A total of 5 studies including 977 patients were identified to be eligible for this meta-analysis. Compared with control group, aspirin group significantly increased pathologic complete response rate from 16.5 to 22.3% (RR 1.41, 95% CI 1.01-1.96, P = 0.041), partial remission rate from 21.8 to 45.7% (RR 1.87, 95% CI 1.37-2.54, P < 0.001), and tumor down-staging rate from 44.4 to 63.8% (RR 1.43, 95% CI 1.17-1.75, P = 0.001). Moreover, aspirin group can reduce local recurrence rate (RR 0.37, 95% CI 0.17-0.84, P = 0.017), improve 3-year survival rate (RR 1.24, 95% CI 1.12-1.36, P < 0.001), and 5-year survival rate (RR 1.29, 95% CI 1.14-1.46, P < 0.001). TSA shows that the meta-analysis results of pathologic complete response rate and local recurrence rate may be a false positive. Furthermore, the meta-analysis results of other study endpoints were further confirmed by TSA.

CONCLUSION

Aspirin, as an adjuvant agent, can enhance the effect of neoadjuvant chemoradiotherapy and improve the prognosis of patients with rectal cancer. Neoadjuvant therapy combined with aspirin may be considered a better option for preoperative rectal cancer patients.

Short-Term Clinical and Oncological Outcome of Prolonging Operation Interval After Neoadjuvant Chemoradiotherapy for Locally Advanced Middle and Low Rectal Cancer

Purpose

The purpose of this study is to evaluate the short-term clinical and oncological outcome of prolonging operation interval to 11 weeks after the end of radiotherapy for locally advanced middle and low rectal cancer.

Methods

A total of 123 patients with stage II/III (cT3/T4 or N+) low and middle rectal cancer who had undergone operation after neoadjuvant chemoradiotherapy were selected. According to the interval time between the last radiotherapy and operation, they were assigned to a short-interval group (SG, <11 weeks, n=66) and long-interval group (LG, ≥11 weeks, n=57). The relations among interval time and short-term clinical outcome and oncological outcome were analyzed.

Results

The analysis found that basic information, clinical characteristics, and preoperative treatment between the two groups had no significant difference. There were no differences in operation time, estimated intraoperative blood loss and postoperative complications. The rate of sphincter preservation in the low and middle rectum was 66.7% in the short-interval group and 59.7% in the long-interval group (P=0.42). The incidence of anastomotic leak in the long-interval group was higher than that in the short-interval group (P=0.08). There was no significant difference in the recovery time of intestinal function and median duration of hospitalization between the two groups. The pathological complete remission rate was 17.07%. Multivariate analysis showed interval time had no influence on pathological complete remission. There was no significant difference in 3-year overall survival and 3-year disease-free survival between the two groups. The risk of recurrence and metastasis in patients with positive lymph nodes was higher than those with negative lymph nodes (P<0.05), HR=4.812 (95% CI 2.4–9.648).

Conclusion

Prolonging the interval time of operation to 11 weeks after neoadjuvant chemoradiotherapy for middle and low rectal cancer does not improve the pathologic complete remission, morbidity, and mortality. There was no significant effect on oncologic outcome after prolonging the operation interval. Therefore, it is safe to prolong the interval of operation to 11 weeks.

YpN0 rectal cancer patients with sterilized lymph nodes after neoadjuvant chemoradiotherapy are of greater risk of recurrence

BACKGROUND

Indication for adjuvant chemotherapy in ypN0 rectal cancer patients after chemoradiotherapy (CRT) is debated. The clinical significance of the presence of sterilized lymph nodes (LNS) in ypN0 patients remains to be determined.

AIMS

To assess the prognostic value of LNS in ypN0 rectal cancers after neoadjuvant CRT.

METHODS

From 2006-2016, 235 patients underwent TME surgery for non-metastatic mid-low rectal cancer after CRT. A lymph node was considered sterilized if there were signs of treatment response (fibrosis, necrosis or mucus) without residual tumor cells.

RESULTS

180 patients (77%) were classified ypN0 and 55 (23%) ypN+. LNS was present in 20 patients (9%). In ypN0 patients, 5-year OS was similar between patients with and without LNS. In contrast, 5-year DFS was significantly lower in ypN0/LNS + patients (58% vs. 78%, p = 0.043) and was similar to those staged ypN+. In multivariate analysis, two factors were independent predictors of DFS: mesorectal grading (OR = 3.14; 95%CI: 1.10-8.34; p = 0.033) and the presence of LNS (OR = 3.93, 95% CI: 1.06-11.81, p = 0.042) CONCLUSION: The presence of LNS in ypN0 rectal cancer after neoadjuvant CRT is associated with an increased risk of recurrence and may be taken into account for the discussion of adjuvant chemotherapy.

Pathological complete response due to a prolonged time interval between preoperative chemoradiation and surgery in locally advanced rectal cancer: analysis from the German StuDoQ|Rectalcarcinoma registry

Background

Preoperative chemoradiotherapy is the recommended standard of care for patients with local advanced rectal cancer. However, it remains unclear, whether a prolonged time interval to surgery results in an increased perioperative morbidity, reduced TME quality or better pathological response. Aim of this study was to determine the time interval for best pathological response and perioperative outcome compared to current recommended interval of 6 to 8 weeks.

Methods

This is a retrospective analysis of the German StuDoQ|Rectalcarcinoma registry. Patients were grouped for the time intervals of “less than 6 weeks”, “6 to 8 weeks”, “8 to 10 weeks” and “more than 10 weeks”. Primary endpoint was pathological response, secondary endpoint TME quality and complications according to Clavien-Dindo classification.

Results

Due to our inclusion criteria (preoperative chemoradiation, surgery in curative intention, M0), 1.809 of 9.560 patients were suitable for analysis. We observed a trend for increased rates of pathological complete response (pCR: ypT0ypN0) and pathological good response (pGR: ypT0-1ypN0) for groups with a prolonged time interval which was not significant. Ultimately, it led to a steady state of pCR (16.5%) and pGR (22.6%) in “8 to 10” and “more than 10” weeks. We were not able to observe any differences between the subgroups in perioperative morbidity, proportion of rectal extirpation (for cancer of the lower third) or difference in TME quality.

Conclusion

A prolonged time interval between neoadjuvant chemoradiation can be performed, as the rate of pCR seems to be increased without influencing perioperative morbidity.

Magnetic Resonance Guided Radiotherapy for Rectal Cancer: Expanding Opportunities for Non-Operative Management

Colorectal cancer is the third most common cancer in men and the second most common in women worldwide, and the incidence is increasing among younger patients. 30% of these malignancies arise in the rectum. Patients with rectal cancer have historically been managed with preoperative radiation, followed by radical surgery, and adjuvant chemotherapy, with permanent colostomies in up to 20% of patients. Beginning in the early 2000s, non-operative management (NOM) of rectal cancer emerged as a viable alternative to radical surgery in select patients. Efforts have been ongoing to optimize neoadjuvant therapy for rectal cancer, thereby increasing the number of patients potentially eligible to forgo radical surgery. Magnetic resonance guided radiotherapy (MRgRT) has recently emerged as a treatment modality capable of intensifying preoperative radiation therapy for rectal cancer patients. This technology may also predict which patients will achieve a complete response to preoperative therapy, thereby allowing for more appropriate selection of patients for NOM. The present work seeks to illustrate the potential role MRgRT could play in personalizing rectal cancer treatment thus expanding the role of NOM in rectal cancer.

Neoadjuvant chemo-radiotherapy for cT3N0 rectal cancer: any benefit over upfront surgery? A propensity score-matched study

PURPOSE

Benefits of neoadjuvant chemo-radiotherapy (CRT) are well known for locally advanced and/or node-positive rectal cancer, but the best timing for CRT has been less explored for cT3N0 patients. The aim of the present study was to compare the 5-year disease-free survival (DFS) probability between neoadjuvant CRT and upfront surgery in patients affected by cT3N0 rectal cancer.

METHODS

A retrospective review of 105 patients affected by cT3N0 rectal cancer, staged by pelvic magnetic resonance imaging and treated at the National Cancer Institute of Milan between 2011 and 2017, was performed: 42 (40.0%) were treated by neoadjuvant CRT and 63 (60.0%) by upfront surgery. Propensity score matching was performed to avoid selection bias, and Cox multivariate regression was used to analyze outcomes.

RESULTS

The 5-year DFS probability was 87.5% in neoadjuvant CRT patients vs. 90.0% in upfront surgery cases (Log-rank p = 0.76). The 5-year loco-regional recurrence-free survival probability was respectively 96.8% vs. 96.3% (Log-rank p = 0.954). On multivariate analysis, neoadjuvant CRT had no impact on DFS when compared to upfront surgery (adjusted HR 0.71, 95%CI 0.18-2.70, p = 0.613), but 61.9% of upfront surgery cases were treated by adjuvant chemo-radiation (adjusted HR 0.41, 95%CI 0.11-1.57, p = 0.196). The only independent predictor of improved DFS was age at diagnosis (adjusted HR 0.95, p = 0.017).

CONCLUSION

CRT should be considered for cT3N0 patients, but its timing (neoadjuvant vs. adjuvant) seems not to affect the disease-free survival in the present cohort of patients.

Neoadjuvant Chemoradiotherapy and Tumor Recurrence in Patients with Early T-Stage Cancer of the Lower Rectum

BACKGROUND

The role neoadjuvant chemoradiotherapy (nCRT) plays in oncological outcomes in early T-stage rectal cancer is uncertain. The present work aims to clarify prognostic outcomes by estimating the effect of nCRT on tumor recurrence prior to major surgery compared with major surgery alone.

PATIENTS AND METHODS

Prospectively collected data were retrospectively analyzed for patients diagnosed with localized rectal adenocarcinoma ≤ 8 cm from the anal verge, with final histopathology ≤ T2 (≤ ypT2/≤ pT2), regardless of magnetic resonance imaging staging, between 1990 and 2017. As the effect of nCRT on recurrence varied over time, thereby violating the Cox proportional hazards assumption, the effect of nCRT on recurrence hazards was estimated using a time-varying multivariate Cox model over two separate time intervals (≤ 1 year and > 1 year postsurgery) by nCRT.

RESULTS

Long-course nCRT was associated with a 5.6-fold increase in the hazard of recurrence ≤ 1 year postsurgery [hazard ratio (HR) 5.6; 95% confidence interval (CI) 1.2-24.9; P = 0.02], but there was no increase in recurrence hazards > 1 year (HR 0.84; 95% CI 0.4-2.0; P = 0.70). In subgroup analysis restricted to ≤ mrT2/≤ ypT2 and ≤ pT2 tumors (omitting > mrT2 tumors), the effect of nCRT on recurrence no longer varied over time, indicating that tumor heterogeneity was responsible for the observed increased recurrence hazards ≤ 1 year postsurgery; That is, > mrT2 tumors that were downstaged to ≤ ypT2 after nCRT were responsible for the time-varying effects of nCRT and increased recurrence hazards ≤ 1 year postsurgery. Subsequently, no difference was found in prognostic outcomes either with or without nCRT before surgery in the homogeneous population of ≤ mrT2/≤ ypT2 and ≤ pT2 tumors.

CONCLUSIONS

No evidence was found to indicate that nCRT prior to surgery reduces tumor recurrence in early T-stage lower rectal cancer compared with surgery alone.

Delay to Adjuvant Chemotherapy: Survival and Recurrence in Patients of Rectal Cancer Treated with Neo-adjuvant Chemoradiotherapy and Surgery

PURPOSE

This aim of the study is to evaluate the survival function and hazard risks of delayed adjuvant chemotherapy (ChT) to distant recurrence risk in patients with non-metastatic rectal cancer treated with neoadjuvant chemoradiotherapy (CRT) and surgery.

METHODS

A single tertiary hospital retrospective cohort study of a duration of 5 years between January 2012 and December 2016 was performed. As no previous study shown a temporal relationship of delay to adjuvant/systemic ChT leading to increased risk of metastatic disease, we compared between our proposed cut-off with the median and mean value determined by our dataset. Time to event analysis and log rank tests were conducted.

RESULTS

A total of 269 patients with rectal cancer were identified. Two hundred eighteen patients were ineligible, leaving 51 patients for final analysis. Patients in the non-delayed group at 23 (proposed) and 25 (median) weeks' cut-off reported better 5 years' disease free survival (DFS) compared with the delayed group by 4.1% and 0.8%. Inversely, at the cut-off 28 (mean) weeks, the delayed group had a better DFS by 4.4%. Females and patients less than 60 years old had better 5-year DFS by 22.8% and 24%. Delayed group has a higher hazard risk ratio (HR) of 1.28 of distant recurrence compared with non-delayed at 23 weeks' cut-off.

CONCLUSION

This study has demonstrated delaying a patient to adjuvant ChT will lower their DFS and increase their HR compared with those whose treatment is not delayed. We have long been too focused on local control; hence, priority needs to be shifted to efforts in managing potential distant disease in a timely manner.

The Role of Adjuvant Chemotherapy in ypT0N0 Rectal Adenocarcinoma

BACKGROUND

In patients who develop a complete pathologic response (ypT0N0) following neoadjuvant chemoradiation, the benefits of postoperative chemotherapy remain uncertain. This study aims to determine whether treatment with adjuvant chemotherapy in ypT0N0 patients affects short- and long-term outcomes.

METHODS

From January 2000 to December 2015, 992 patients at our institution underwent surgery for rectal adenocarcinoma following treatment with neoadjuvant chemoradiation. A complete pathologic response was noted in 96 (9.7%) patients. Adjuvant chemotherapy was administered to 60 (62.5%) patients. We reviewed clinical and pathological records and compared outcomes in ypT0N0 patients who received adjuvant chemotherapy to those who did not.

RESULTS

The mean age of patients who received adjuvant chemotherapy was 55.6 ± 11.5 years, compared to 62.1 ± 11.7 years for those who did not (p = 0.008). Among the two groups, mean follow-up time after surgery was 5.3 ± 4.1 years for the adjuvant group and 8.3 ± 5.5 years for the non-adjuvant cohort (p = 0.003). The 1, 3, and 5-year survival rates were 100.0%, 97.7%, and 92.1% for patients who received adjuvant chemotherapy and 97.2%, 94.1%, and 90.7% for those who did not (p = 0.382). In a subanalysis of patients with available follow-up information, we observed 3/53 (5.7%) disease recurrences in patients who received adjuvant chemotherapy, compared to 2/18 (11.1%) in those who were not treated postoperatively (p = 0.456).

CONCLUSION

In patients with ypT0N0 rectal adenocarcinoma, we found equivalent survival and recurrence outcomes. Further study will be necessary to determine the importance of adjuvant chemotherapy following ypT0N0 resection.

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.

Radiomics features on radiotherapy treatment planning CT can predict patient survival in locally advanced rectal cancer patients

This retrospective study was to investigate whether radiomics feature come from radiotherapy treatment planning CT can predict prognosis in locally advanced rectal cancer patients treated with neoadjuvant chemoradiation followed by surgery. Four-hundred-eleven locally advanced rectal cancer patients which were treated with neoadjuvant chemoradiation enrolled in this study. All patients’ radiotherapy treatment planning CTs were collected. Tumor was delineated on these CTs by physicians. An in-house radiomics software was used to calculate 271 radiomics features. The results of test-retest and contour-recontour studies were used to filter stable radiomics (Spearman correlation coefficient > 0.7). Twenty-one radiomics features were final enrolled. The performance of prediction model with the radiomics or clinical features were calculated. The clinical outcomes include local control, distant control, disease-free survival (DFS) and overall survival (OS). Model performance C-index was evaluated by C-index. Patients are divided into two groups by cluster results. The results of chi-square test revealed that the radiomics feature cluster is independent of clinical features. Patients have significant differences in OS (p = 0.032, log rank test) for these two groups. By supervised modeling, radiomics features can improve the prediction power of OS from 0.672 [0.617 0.728] with clinical features only to 0.730 [0.658 0.801]. In conclusion, the radiomics features from radiotherapy CT can potentially predict OS for locally advanced rectal cancer patients with neoadjuvant chemoradiation treatment.

Knockdown Of TRIM31 Enhances Colorectal Cancer Radiosensitivity By Inducing DNA Damage And Activating Apoptosis

Purpose

Biomarkers that predict radiosensitivity are essential for personalized radiotherapy. We performed microarray analysis for rectal cancer patients between those with good response and poor response to preoperative radiotherapy and found that patients with lower expression of tripartite motif-containing protein 31 (TRIM31) showed a better response. In this study, we confirmed the effects of TRIM31 on radiosensitivity by knockdown of TRIM31 in colorectal cancer cells.

Methods and materials

Human colorectal cancer cell lines HT-29 and SW480, which are TRIM31 stably knocked-down, were used for analysis. We studied the level of DNA damage and the change of relative proteins after irradiation in TRIM31-knockdown cells. Flow cytometry was used to test for apoptosis, cell cycle stage, and reactive oxygen species (ROS) levels after irradiation. Cell survival was measured by cloning assay. Proteins related to DNA damage were evaluated by Western blotting.

Results

The percentage of apoptotic cells and the levels of ROS were elevated, and the survival fraction was reduced in TRIM31-knockdown cells. The expression levels of the DNA damage proteins phosphorylated ataxia-telangiectasia mutation (P-ATM), DNA protein kinases (DNA-PKs), and γ-H2AX were higher in TRIM31-knockdown cells.

Conclusion

Knockdown of TRIM31 increases DNA damage and radiosensitivity in colorectal cancer cells.

Prediction of tumor response of rectal cancer cells via 3D cell culture and in vitro cytotoxicity assay before initiating preoperative chemoradiotherapy

The aim of the present study was to investigate the utility of 3D cell culture and in vitro cytotoxicity assays, performed using cells derived from biopsies obtained prior to the initiation of preoperative chemoradiotherapy (preop-CRT), in predicting tumor response to chemoradiotherapy following preop-CRT in rectal cancer. Biopsies were obtained from 49 patients with locally advanced rectal cancer that underwent preop-CRT between August 2015 and March 2017. Tumor tissue was obtained before initiating preop-CRT. The response to chemoradiation was assessed by in vitro cytotoxicity assay following 3D cell culture and radiation treatment. The associations between the results from the cytotoxicity assay, and tumor regression grade (TRG) and yp node (ypN) positivity were investigated. Among 49 patients, 26 patients were available for analysis. Cytotoxicity ranged from 25.5-72.6% (median, 47.6%). There was no difference in cytotoxicity according to the TRGs 1-5 (P=0.940), or good tumor response (TRGs 1-2 vs. TRGs 3-5; P=0.729). However, there was a significant difference in cytotoxicity between the ypN-negative and -positive groups (53.2±14.1 and 38.7±10.1, respectively; P=0.021). Following dichotomization of patients with 45% cut-off value, the cytotoxicity assay was the only factor that predicted ypN positivity in multivariate analysis (odds ratio, 13; 95% confidence interval, 1.2-133.2; P=0.031). In conclusion, the cytotoxicity assay using the 3D cell culture method can be used to predict tumor response, particularly ypN positivity, in patients with rectal cancer who are scheduled for preop-CRT.

MR-guided radiotherapy in rectal cancer: First clinical experience of an innovative technology

•This study represents one of the first reports of online MRgRT.•Integrated Low-field MR provides better anatomical visualization than CBCT or MVCT.•Better visualization of the target can help to reduce the margins from CTV to PTV.•MRgRT appears a feasible option in rectal cancer treatment offering potential benefits.•MRgRT represents a promising technology for rectal cancer management.

Evolving Treatment Options and Future Directions for Locally Advanced Rectal Cancer

Locally advanced rectal cancer can be biologically heterogeneous, but imaging advances have improved clinical assessment of primary tumor and involved lymph nodes in relation to pelvic structures and intended surgical planes. Contemporary treatment for rectal cancer is tailored to the individual patient through multidisciplinary collaboration among diagnosticians, surgeons, medical oncologists, and radiation oncologists to minimize local recurrence and distant metastases. Furthermore, patient preferences and quality of life preservation are becoming more relevant in the decision-making, and upcoming treatment strategies specifically are designed to minimize toxicities and long-term morbidity. Accumulating data have continued to support the use of total neoadjuvant therapy, namely the completion of: (1) multiagent cytotoxic chemotherapy; and (2) pelvic radiation with or without a radiosensitizing agent, before surgery. The total neoadjuvant therapy strategy not only eliminates potentially occult metastases early but also opens up the possibility of nonsurgical management for those who decline or are unfit for surgery. Finally, noncytotoxic agents in combination with established chemotherapy agents along with potentially predictive biomarkers are also being actively investigated to further improve the clinical outcomes of rectal cancer.

MRI-Based Radiomics Predicts Tumor Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Background: Conventional methods for predicting treatment response to neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC) are limited.

Methods: This study retrospectively recruited 134 LARC patients who underwent standard nCRT followed by total mesorectal excision surgery in our institution. Based on pre-operative axial T2-weighted images, machine learning radiomics was performed. A receiver operating characteristic (ROC) curve was performed to test the efficiencies of the predictive model.

Results: Among the 134 patients, 32 (23.9%) achieved pathological complete response (pCR), 69 (51.5%) achieved a good response, and 91 (67.9%) achieved down-staging. For prediction of pCR, good-response, and down-staging, the predictive model demonstrated high classification efficiencies, with an AUC value of 0.91 (95% CI: 0.83–0.98), 0.90 (95% CI: 0.83–0.97), and 0.93 (95% CI: 0.87–0.98), respectively.

Conclusion: Our machine learning radiomics model showed promise for predicting response to nCRT in patients with LARC. Our predictive model based on the commonly used T2-weighted images on pelvic Magnetic Resonance Imaging (MRI) scans has the potential to be adapted in clinical practice.

Novelty and Impact Statements: Methods for predicting the response of the locally advanced rectal cancer (LARC, T3-4, or N+) to neoadjuvant chemoradiotherapy (nCRT) is lacking. In the present study, we developed a new machine learning radiomics method based on T2-weighted images. As a non-invasive tool, this method facilitates prediction performance effectively. It achieves a satisfactory overall diagnostic accuracy for predicting of pCR, good response, and down-staging show an AUC of 0.908, 0.902, and 0.930 in LARC patients, respectively.

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.

Locally advanced rectal cancer transcriptomic-based secretome analysis reveals novel biomarkers useful to identify patients according to neoadjuvant chemoradiotherapy response

Most patients with locally advanced rectal cancer (LARC) present incomplete pathological response (pIR) to neoadjuvant chemoradiotherapy (nCRT). Despite the efforts to predict treatment response using tumor-molecular features, as differentially expressed genes, no molecule has proved to be a strong biomarker. The tumor secretome analysis is a promising strategy for biomarkers identification, which can be assessed using transcriptomic data. We performed transcriptomic-based secretome analysis to select potentially secreted proteins using an in silico approach. The tumor expression profile of 28 LARC biopsies collected before nCRT was compared with normal rectal tissues (NT). The expression profile showed no significant differences between complete (pCR) and incomplete responders to nCRT. Genes with increased expression (pCR = 106 and pIR = 357) were used for secretome analysis based on public databases (Vesiclepedia, Human Cancer Secretome, and Plasma Proteome). Seventeen potentially secreted candidates (pCR = 1, pIR = 13 and 3 in both groups) were further investigated in two independent datasets (TCGA and GSE68204) confirming their over-expression in LARC and association with nCRT response (GSE68204). The expression of circulating amphiregulin and cMET proteins was confirmed in serum from 14 LARC patients. Future studies in liquid biopsies could confirm the utility of these proteins for personalized treatment in LARC patients.

Predictors and Risk Factors of Pathologic Complete Response Following Neoadjuvant Chemoradiotherapy for Rectal Cancer: A Population-Based Analysis

Background: Patients with rectal cancer who achieve pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) may have a better prognosis and may be eligible for non-operative management. The aim of this research was to identify variables for predicting pCR in rectal cancer patients after nCRT and to define clinical risk factors for poor outcome after pCR to nCRT and radical resection in rectal cancer patients. Methods: A retrospective review was performed using the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2013. Non-metastatic rectal cancer patients who received radical resection after neoadjuvant chemoradiotherapy were included in this study. Multivariate analysis of the association between clinicopathological characteristics and pCR was performed, and a logistic regression model was used to identify independent predictors for pCR. A nomogram based on the multivariate logistics regression was built with decision curve analyses to evaluate the clinical usefulness. Results: A total of 6,555 patients were included in this study. The proportion of patients with pCR was 20.5% (n = 1,342). The nomogram based on multivariate logistic regression analysis showed that clinical T4 and N2 stages were the most significant independent clinical predictors for not achieving pCR, followed by mucinous adenocarcinoma and positive pre-treatment serum CEA results. The 3-year overall survival rate was 92.4% for those with pCR and 88.2% for those without pCR. Among all the pCR patients, mucinous adenocarcinoma patients had the worst survival, with a 3-year overall survival rate of 67.5%, whereas patients with common adenocarcinoma had an overall survival rate of 93.8% (P < 0.001). Univariate and multivariate analyses showed that histology and clinical N2 stage were independent risk factors. Conclusion: Mucinous adenocarcinoma, positive pre-treatment serum CEA results, and clinical T4 and N2 stages may impart difficulty for patients to achieve pCR. Mucinous adenocarcinoma and clinical N2 stage might be indicative of a prognostically unfavorable biological tumor profile with a greater propensity for local or distant recurrence and decreased survival.

Increased Levels of Genomic Instability and Mutations in Homologous Recombination Genes in Locally Advanced Rectal Carcinomas

Pre-operative 5-fluoracil-based chemoradiotherapy (nCRT) is the standard treatment for patients with locally advanced rectal cancer (LARC). Patients with pathological complete response (pCR–0% of tumor cells in the surgical specimen after nCRT) have better overall survival and lower risk of recurrence in comparison with incomplete responders (pIR). Predictive biomarkers to be used for new therapeutic strategies and capable of stratifying patients to avoid overtreatment are needed. We evaluated the genomic profiles of 33 pre-treatment LARC biopsies using SNP array and targeted-next generation sequencing (tNGS). Based on the large number of identified genomic alterations, we calculated the genomic instability index (GII) and three homologous recombination deficiency (HRD) scores, which have been reported as impaired DNA repair markers. We observed high GII in our LARC cases, which was confirmed in 165 rectal cancer cases from TCGA. Patients with pCR presented higher GII compared with pIR. Moreover, a negative correlation between GII and the fraction of tumor cells remaining after surgery was observed (ρ = –0.382, P = 0.02). High HRD scores were detected in 61% of LARC, of which 70% were incomplete responders. Using tNGS (105 cancer-related genes, 13 involved in HR and 5 in mismatch repair pathways), we identified 23% of cases with mutations in HR genes, mostly in pIR cases (86% of mutated cases). In agreement, the analysis of the TCGA dataset (N = 145) revealed 21% of tumors with mutations in HR genes. The HRD scores were shown to be predictive of better response to PARP-inhibitors and platinum-based chemotherapy in breast and ovarian cancer. Our results suggest that the same strategy could be applied in a set of LARC patients with HRD. In conclusion, we identified high genomic instability in LARC, which was related to alterations in the HR pathway, especially in pIR. These findings suggest that patients with impaired HRD would clinically benefit from PARP-inhibitors and platinum-based therapy.

Circulating Biomarkers for Response Prediction of Rectal Cancer to Neoadjuvant Chemoradiotherapy

Rectal cancer response to neoadjuvant Chemoradiotherapy (pCRT) is highly variable. In fact, it has been estimated that only about 21 % of patients show pathologic Complete Response (pCR) after therapy, while in most of the patients a partial or incomplete tumour regression is observed. Consequently, patients with a priori chemoradioresistant tumour should not receive the treatment, which is associated with substantial adverse effects and does not guarantee any clinical benefit. For Locally Advanced Rectal Cancer Patients (LARC), a standardized neoadjuvant treatment protocol is applied, the identification and the usefulness of prognostic or predictive biomarkers can improve the antitumoural treatment strategy, modifying the sequence, dose, and combination of radiotherapy, chemotherapy and surgical resection. For these reasons, a growing number of studies are actually focussed on the discovery and investigation of new predictive biomarkers of response to pCRT. In this review, we have selected the most recent literature (2012-2017) regarding the employment of blood-based biomarkers potentially predicting pCR in LARC patients and we have critically discussed them to highlight their real clinical benefit and the current limitations of the proposed methodological approaches.

Pathological complete response may underestimate distant metastasis in locally advanced rectal cancer following neoadjuvant chemoradiotherapy and radical surgery: Incidence, metastatic pattern, and risk factors

AIM

To evaluate the pattern of tumor relapse of pathological complete response (pCR) patients with locally advanced rectal cancer (LARC) following neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME), and to identify predictive factors of distant metastasis in pCR patients after nCRT.

METHOD

This was a retrospective analysis of 118 LARC patients who achieved a pCR following nCRT and TME from 2008 to 2015. Clinicopathological and therapeutic parameters were evaluated as possible predictors of distant metastasis-free survival (DMFS), and COX regression analysis was performed.

RESULTS

After a median follow-up of 57 months, the 5-year overall and disease-free survival rates were 94.7% and 88.1%, respectively. Overall, 6 patients (5.1%) died, no local recurrence occurred, 13 patients (11%) developed distant metastases, including lung (n = 5), liver (n = 2), bone (n = 3), lung and brain (n = 1), peritoneal (n = 1), and spleen (n = 1) metastasis. On univariate analysis, tumor distance from the anal verge (HR = 0.706, P = 0.039), acellular mucin pools (HR = 6.687, P = 0.002), and MUC1 expression (HR = 8.280, P < 0.001) were independently associated with DMFS. COX regression demonstrated that MUC1 expression (HR = 3.812, P = 0.041) remained to be an independent predictor of DMFS in pCR patients.

CONCLUSION

Distant metastasis still remained a major concern in pCR patients following nCRT and TME. Tumor distance from the anal verge, acellular mucin pools, and MUC1 expression were associated with distant metastasis in patients with pCR. MUC1 staining remained to be an independent risk factor for DMFS. Such information could facilitate treatment decision in these patients, such as adjuvant chemotherapy and follow-up.

Obesity as an independent predictive factor for pathologic complete response after neoadjuvant chemoradiation in rectal cancer

PURPOSE

The predictive role of obesity on pathologic complete response (pCR) after neoadjuvant chemoradiation (nCRT) in rectal cancer remains controversial. This study aimed to evaluate the association between obesity and pathologic response in patients with rectal cancer following nCRT.

METHODS

A total of 320 patients with primary rectal cancer who underwent curative resection after nCRT between January 2010 and September 2014 were enrolled in this study. Obesity was defined as body mass index of ≥25 kg/m2. Clinicopathologic characteristics were analyzed to identify independent predictive factors for pCR.

RESULTS

Among the included patients, 23.4% (n = 75) were obese, and 14.7% (n = 47) showed pCR. Baseline characteristics were generally similar between obese and nonobese patients, except that women (P = 0.001) and cT2 tumors (P = 0.001) were more common in the obese group. Multivariate logistic regression analysis revealed that obesity (odds ratio [OR] = 2.051; 95% confidence interval [CI], 1.009-4.168), cT2 (OR, 3.614; 95% CI, 1.166-11.202), and pretreatment carcinoembryonic antigen <5 ng/mL (OR, 2.921; 95% CI, 1.365-6.253) were independent predictors for pCR. Obesity was not associated with disease-free survival or local recurrence-free survival.

CONCLUSION

Obesity was an independent predictive factor for pCR following nCRT in rectal cancer, but was not associated with recurrence. Further studies are needed to clarify the association between obesity and prognosis of rectal cancer after nCRT.

Additional Chemotherapy with 5-FU plus Leucovorin between Preoperative Chemoradiotherapy and Surgery Improved Treatment Outcomes in Patients with Advanced Rectal Cancer

Purpose: The aim of the preliminary study was to evaluate the efficacy and safety of 4-week chemotherapy with 5-Fluorouracil and leucovorin (LV5FU2) during the resting periods between preoperative CRT and surgery in patients with LARC. Materials and Methods: Standard preoperative CRT was delivered to the entire pelvis at a total dose of 5040 Gy of radiation with concurrent 5-FU or capecitabine for 6 weeks. Twenty-three patients received additional preoperative chemotherapy with two cycles of 5-FU and LV (LV 200 mg/m2 and 5-FU bolus 400 mg/m2 on day 1, and 5-FU infusion 2400 mg/m2 for 46 hrs, every 2 weeks) after preoperative CRT. Surgery was performed at 2-4 weeks following the completion of preoperative chemotherapy. Results: Between May 2013 and January 2015, 23 patients underwent preoperative CRT, with additional chemotherapy and surgery, and 23 patients completed the scheduled treatment. The median follow-up duration was 42.0 months. The tumor down-staging rate was observed in 65.2%, and pathologic complete remission (pCR) was noted in 5 patients (21.7%). T and N down-staging were observed in 16 (69.6%) and 14 (60.9%) patients, respectively. The four-year disease-free survival (DFS) rate was 73.9% and the four-year overall survival (OS) rate was 90.9% in patients who received additional chemotherapy. The four-year DFS rate was 100% in the tumor down-staging group vs. 25.0% in the non-down staging group treated with additional chemotherapy (P <0.001). There was also a significant difference of the four-year OS rate 100% in the tumor down-staging group compared with 71.4% in the non-down staging group (P = 0.031). Conclusions: This preliminary study showed that additional preoperative chemotherapy with LV5FU2 was well tolerable and had an improvement in the downstaging rate and survival. Randomized controlled trial of this strategy is encouraged for definitive conclusions.

A quest for sphincter-saving surgery in ultralow rectal tumours-a single-centre cohort study

INTRODUCTION

Despite the progress in the treatment of colorectal cancer, there is still no optimal strategy for tumours located adjacent to the anal sphincter. This study aims to evaluate oncological and functional results of surgery for rectal cancer in unfavourable locations in proximity to anal sphincters.

MATERIALS AND METHODS

Patients with rectal cancer, which was either initially infiltrating the anal sphincter or located in the close proximity of the sphincter, were included in the study. Patients were submitted to extralevator abdominoperineal resection (APR), intersphincteric resection, or transanal total mesorectal excision (TaTME). Primary outcomes were perioperative data: operative time, blood loss, complications, length of stay (LOS), and 30-day mortality. Secondary outcomes were pathological quality of the specimens and functional outcome 6 months after defunctioning ileostomy closure.

RESULTS

Among patients with cancer adjacent to the anal sphincter, 13 (25%) underwent APR, 14 (27%) patients were submitted to intersphincteric resection, and 25 (48%) patients were treated with the TaTME approach. Operative time was 240 (210-270 IQR) for APR, 212.5 (170-260 IQR) for intersphincteric resection, and 270 (240-330 IQR) for TaTME (p = 0.018). Perioperative morbidity was 31% for APR, 36% for intersphincteric resections, and 12% for the TaTME group (p = 0.181). Complete mesorectal excision was achieved in 92% of specimens in the TaTME group, 93% in intersphincteric resections, and 78% in the APR group (p = 0.72). Median circumferential resection margin in APR was 6 mm (4-7 IQR), in intersphincteric resections 7.5 mm (2.5-10 IQR), and in the TaTME group 4 mm (2.8-8 IQR). All patients after intersphincteric resections developed major low anterior resection syndrome (LARS). Four patients in the TaTME group developed minor LARS, and 21 had major LARS.

CONCLUSION

Sphincter-saving rectal resections are a feasible alternative to APR with good clinical, pathological, and oncological outcomes. Intersphincteric resections and TaTME seem to be equal in terms of clinicopathological results. The functional outcome is yet to be investigated.

TRIAL REGISTRATION

The study was retrospectively registered in Thai Clinical Trials Registry (23-07-2018, ID TCTR20180724001 ).

Induction chemotherapy, chemoradiotherapy and consolidation chemotherapy in preoperative treatment of rectal cancer - long-term results of phase II OIGIT-01 Trial

Background The purpose of the study was to improve treatment efficacy for locally advanced rectal cancer (LARC) by shifting half of adjuvant chemotherapy preoperatively to one induction and two consolidation cycles. Patients and methods Between October 2011 and April 2013, 66 patients with LARC were treated with one induction chemotherapy cycle followed by chemoradiotherapy (CRT), two consolidation cycles, surgery and three adjuvant capecitabine cycles. Radiation doses were 50.4 Gy for T2-3 and 54 Gy for T4 tumours in 1.8 Gy daily fraction. The doses of concomitant and neo/adjuvant capecitabine were 825 mg/m2/12h and 1250mg/m2/12h, respectively. The primary endpoint was pathologic complete response (pCR). Results Forty-three (65.1%) patients were treated according to protocol. The compliance rates for induction, consolidation, and adjuvant chemotherapy were 98.5%, 93.8% and 87.3%, respectively. CRT was completed by 65/66 patients, with G ≥ 3 non-hematologic toxicity at 13.6%. The rate of pCR (17.5%) was not increased, but N and the total-down staging rates were 77.7% and 79.3%, respectively. In a median follow-up of 55 months, we recorded one local relapse (LR) (1.6%). The 5-year disease-free survival (DFS) and overall survival (OS) rates were 64.0% (95% CI 63.89-64.11) and 69.5% (95% CI 69.39-69.61), respectively. Conclusions In LARC preoperative treatment intensification with capecitabine before and after radiotherapy is well tolerated, with a high compliance rate and acceptable toxicity. Though it does not improve the local effect, it achieves a high LR rate, DFS, and OS.

Clinical and molecular diagnosis of pathologic complete response in rectal cancer: an update

INTRODUCTION

The standard of care for locally advanced rectal cancer includes neoadjuvant chemoradiation with subsequent total mesorectal excision. This approach has shown various degrees of response to neoadjuvant chemoradiation (ranging from complete response to further tumor growth), which have substantial prognostic and therapeutic implications. A total regression of the tumor is a predictor of superior oncologic outcomes compared with partial responders and non-responders. Further, this concept has opened the possibility of nonoperative strategies for complete responders and explains the widespread research interest in finding clinical, radiographic, pathologic, and biochemical parameters that allow for identification of these patients. Areas covered: The present review evaluates the most recent efforts in the literature to identify predictors of patients likely to achieve a complete response following neoadjuvant treatment for the management of rectal cancer. This includes clinical predictors of pathologic complete response such as tumor location, size, and stage, molecular predictors such as tumor biology and microRNA, serum biomarkers such as carcinoembryogenic antigen and nomograms. Expert commentary: There has been significant progress in our ability to predict pathological complete response. However, more high-quality research is still needed to use this concept to confidently dictate clinical management.