Rectal cancer: Neoadjuvant chemoradiotherapy

Executive Summary of the American Radium Society on Appropriate Use Criteria for Nonoperative Management of Rectal Adenocarcinoma: Systematic Review and Guidelines

For patients with rectal cancer, the standard approach of chemotherapy, radiation therapy, and surgery (trimodality therapy) is associated with significant long-term toxicity and/or colostomy for most patients. Patient options focused on quality of life (QOL) have dramatically improved, but there remains limited guidance regarding comparative effectiveness. This systematic review and associated guidelines evaluate how various treatment strategies compare to each other in terms of oncologic outcomes and QOL. Cochrane and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) methodology were used to search for prospective and retrospective trials and meta-analyses of adequate quality within the Ovid Medline database between January 1, 2012, and June 15, 2023. These studies informed the expert panel, which rated the appropriateness of various treatments in 6 clinical scenarios through a well-established consensus methodology (modified Delphi). The search process yielded 197 articles that advised voting. Increasing data have shown that nonoperative management (NOM) and primary surgery result in QOL benefits noted over trimodality therapy without detriment to oncologic outcomes. For patients with rectal cancer for whom total mesorectal excision would result in permanent colostomy or inadequate bowel continence, NOM was strongly recommended as usually appropriate. Restaging with tumor response assessment approximately 8 to 12 weeks after completion of radiation therapy/chemoradiation therapy was deemed a necessary component of NOM. The panel recommended active surveillance in the setting of a near-complete or complete response. In the setting of NOM, 54 to 56 Gy in 27 to 31 fractions concurrent with chemotherapy and followed by consolidation chemotherapy was recommended. The panel strongly recommends primary surgery as usually appropriate for a T3N0 high rectal tumor for which low anterior resection and adequate bowel function is possible, with adjuvant chemotherapy considered if N+. Recent data support NOM and primary surgery as important options that should be offered to eligible patients. Considering the complexity of multidisciplinary management, patients should be discussed in a multidisciplinary setting, and therapy should be tailored to individual patient goals/values.

The association of preoperative radiotherapy and surgery for AJCC stage I-III rectal adenocarcinoma: a population-based study

BACKGROUND

With the increasing application of neoadjuvant therapy in rectal adenocarcinoma, there remain many controversies in clinical practical applications. Preoperative radiotherapy (PR) can limit the surgical plane and potentially affect the quality of surgical treatment. This study aimed to investigate the potential impact of PR on the surgical quality of rectal adenocarcinoma.

METHODS

This retrospective study analyzed the clinicopathological data from 6,585 AJCC stage I-III rectal adenocarcinoma in the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. Kaplan-Meier survival analysis and multivariate Cox proportional were used to assess the impact of PR on survival. Propensity score matching (PSM) was employed to balance the baseline covariates between the PR and non-PR groups and to compare postoperative pathological differences.

RESULTS

After PSM, PR did not improve overall survival (OS) in stages I (p = 0.33), II (p = 0.37), and III (p = 0.14) patients. Multivariate Cox analysis indicated that PR was not an independent prognostic factor for patients. Restricted cubic spline (RCS) analysis demonstrated a nonlinear negative correlation between OS hazard ratios and both circumferential resection margin (CRM) and lymph node evaluation (LNE). Compared to the non-PR group, patients in the PR group had lower tumor deposits (TD) (p < 0.001), positive CRM (p = 0.191), and perineural invasion (PNI) (p = 0.001).

CONCLUSION

PR is not an independent prognostic factor for rectal adenocarcinoma patients. However, PR can reduce the likelihood of TD, CRM, and PNI, thereby potentially influencing the quality of surgery.

IMMUNOREACT 0: Biopsy-based immune biomarkers as predictors of response to neoadjuvant therapy for rectal cancer-A systematic review and meta-analysis

BACKGROUND

The main therapy for rectal cancer patients is neoadjuvant therapy (NT) followed by surgery. Immune biomarkers are emerging as potential predictors of the response to NT. We performed a meta-analysis to estimate their predictive significance.

METHODS

A systematic literature search of PubMed, Ovid MEDLINE and EMBASE databases was performed to identify eligible studies. Studies on patients with rectal cancer undergoing NT in which the predictive significance of at least one of the immunological markers of interest was assessed by immunohistochemistry (IHC) in pretreatment biopsies were included.

RESULTS

Seventeen studies reporting sufficient data met the inclusion criteria for meta-analysis. High levels of total CD3+, CD4+ and CD8+ tumor infiltrating lymphocytes (TILs), as well as stromal and intraepithelial CD8+ compartments, significantly predicted good pathological response to NT. Moreover, high levels of total (tumoral and immune cell expression) PD-L1 resulted associated to a good pathological response. On the contrary, high levels of intraepithelial CD4+ TILs were correlated with poor pathological response. FoxP3+ TILs, tumoral PD-L1 and CTLA-4 were not correlated to the treatment response.

CONCLUSION

This meta-analysis indicated that high-density TILs might be predictive biomarkers of pathological response in patients that underwent NT for rectal cancer.

Restaging of rectal cancer with hybrid positron emission tomography magnetic resonance imaging after preoperative chemoradiotherapy

Introduction

This study determines the sensitivity and specificity of positron emission tomography/magnetic resonance imaging (PET/MRI) parameters in predicting treatment response in patients with localised rectal cancer who have undergone preoperative chemoradiotherapy (CRT).

Method

Patients with stage I-III adenocarcinoma of the rectum planned for preoperative CRT followed by surgery were recruited. Patients had PET/MRI scans at baseline and 6-8 weeks post-CRT. Functional MRI and PET parameters were assessed for their diagnostic accuracy for tumour regression grade (TRG). Nonparametric receiver operating characteristic analysis was employed to determine the area under the ROC curve (AUC), and the sensitivity and specificity of each quantile cut-off.

Results

A total of 31 patients were recruited, of whom 20 completed study protocol. All patients included had mid or lower rectal tumours. There were 16 patients (80%) with node-positive disease at presentation. The median time to surgery was 75.5 days (range 52-106 days). Histopathological assessment revealed 20% good responders (TRG 1/2), and the remaining 80% of patients had a poor response (TRG 3/4). When predicting good responders, the AUC values for percent maximum thickness reduction and percent apparent diffusion coefficient (ADC) change were 0.82 and 0.73, respectively. A maximum thickness reduction cut-off of >47% and a percent ADC change of >20% yielded a sensitivity and specificity of 75%/95% and 75%/73%, respectively.

Conclusion

Parameters such as percent maximum thickness reduction and percent ADC change may be useful for predicting good responders in patients undergoing preoperative CRT for rectal cancer. Larger studies are warranted to establish the utility of PET/MRI in rectal cancer staging.

Standard versus longer interval of radical resection after neoadjuvant chemoradiotherapy in locally advanced rectal cancer: A 20-year single-center experience & propensity-score matching

BACKGROUND AND OBJECTIVES

Despite the standard interval of 6-8 weeks between neoadjuvant chemoradiotherapy (nCRT) and surgery, it is debated whether an interval of >8 weeks increases the pathologic complete response (pCR) rate. We investigated the interval between nCRT and surgery, and its impact on oncological outcomes and postoperative complications in patients with locally advanced rectal cancer.

METHODS

We retrospectively reviewed patients with rectal cancer who underwent total mesorectal excision after long-course nCRT between 2000 and 2020. They were divided into two groups-those who underwent surgery at 6-8 and >8 weeks after nCRT. Surgical outcomes (stoma rate and postoperative complications), pCR, tumor regression grade (TRG), recurrence-free survival (RFS), and overall survival (OS) were compared.

RESULTS

We selected 770/1153 patients with rectal cancer, including 502 and 268 patients surgically treated at 6-8 and >8 weeks after nCRT, respectively. The pCR rates were similar between the two groups (14.7% vs. 15.3%, p = 0.836), while the TRG was significantly better in the >8 weeks group (p = 0.267). Additionally, the postoperative complications, recurrence, 5-year RFS, and OS rates were not significantly different between the two groups.

CONCLUSIONS

Although tumor regression increased in the >8 weeks group, the oncological benefits of surgery >8 weeks after nCRT remain uncertain.

Statins increase pathological response in locally advanced rectal cancer treated with chemoradiation: a multicenter experience

Aims: To investigate the influence of various concomitant medications on outcomes in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiation. Materials & methods: The authors retrospectively identified 246 patients from 2003 to 2018, collecting demographic and clinicopathological data of interest. Odds ratio (OR) was used to assess the association between concomitant drugs and outcomes. Results: The authors found an association between statins and a Dworak regression grade of 3-4 (OR = 8.78; p = 0.01). Furthermore, statins were significantly associated with more frequent chemoradiation-related toxicity (OR = 2.39; p = 0.0098) and chemotherapy dose reduction or discontinuation (OR = 2.26; p = 0.03). Conclusion: Despite higher frequency of radiotherapy and chemotherapy interruption or dose reduction, the concomitant use of statins during neoadjuvant chemoradiation proved to be associated with better tumor regression.

ACO/ARO/AIO-21 - Capecitabine-based chemoradiotherapy in combination with the IL-1 receptor antagonist anakinra for rectal cancer Patients: A phase I trial of the German rectal cancer study group

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Response to chemoradiotherapy in rectal cancer is highly heterogeneous, ranging from complete response to tumor progression.

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Interleukin-1 signaling polarizes cancer-associated fibroblasts (CAF) towards an inflammatory phenotype and predisposes iCAFs to irradiation-induced senescence.

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Targeting interleukin-1 could potentially reconstitute the tumor microenvironment and improve therapy response.

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The ACO/ARO-AIO-21 phase I trial is testing the interleukin-1 receptor antagonist anakinra in combination with fluoropyrimidine-based chemoradiotherapy in rectal cancer.

Purpose

Methods/Design

Discussion

Predicting response to neoadjuvant chemoradiotherapy in rectal cancer: from biomarkers to tumor models

Colorectal cancer (CRC) is a major contributor to cancer-associated morbidity worldwide and over one-third of CRC is located in the rectum. Neoadjuvant chemoradiotherapy (nCRT) followed by surgical resection is commonly applied to treat locally advanced rectal cancer (LARC). In this review, we summarize current and novel concepts of neoadjuvant therapy for LARC such as total neoadjuvant therapy and describe how these developments impact treatment response. Moreover, as response to nCRT is highly divergent in rectal cancers, we discuss the role of potential predictive biomarkers. We review recent advances in biomarker discovery, from a clinical as well as a histopathological and molecular perspective. Furthermore, the role of emerging predictive biomarkers derived from the tumor environment such as immune cell composition and gut microbiome is presented. Finally, we describe how different tumor models such as patient-derived cancer organoids are used to identify novel predictive biomarkers for chemoradiotherapy (CRT) in rectal cancer.

Inflammatory fibroblasts mediate resistance to neoadjuvant therapy in rectal cancer

Standard cancer therapy targets tumor cells without considering possible damage on the tumor microenvironment that could impair therapy response. In rectal cancer patients we find that inflammatory cancer-associated fibroblasts (iCAFs) are associated with poor chemoradiotherapy response. Employing a murine rectal cancer model or patient-derived tumor organoids and primary stroma cells, we show that, upon irradiation, interleukin-1α (IL-1α) not only polarizes cancer-associated fibroblasts toward the inflammatory phenotype but also triggers oxidative DNA damage, thereby predisposing iCAFs to p53-mediated therapy-induced senescence, which in turn results in chemoradiotherapy resistance and disease progression. Consistently, IL-1 inhibition, prevention of iCAFs senescence, or senolytic therapy sensitizes mice to irradiation, while lower IL-1 receptor antagonist serum levels in rectal patients correlate with poor prognosis. Collectively, we unravel a critical role for iCAFs in rectal cancer therapy resistance and identify IL-1 signaling as an attractive target for stroma-repolarization and prevention of cancer-associated fibroblasts senescence.

Rapid Initiation of Neoadjuvant Chemoradiotherapy After Diagnosis is Associated With Improved Pathologic Response in Locally Advanced Rectal Cancer

INTRODUCTION

In rectal cancer, neoadjuvant chemoradiation (NCRT) is preferred because of toxicity profile, improved resectability and sphincter preservation, although with no impact on overall survival. Pathologic complete response (pCR) to NCRT has been linked with longer disease-free survival (DFS). The study purpose was to evaluate an association between clinical factors and treatment schedule with tumor response and treatment outcome, among patients with locally advanced rectal cancer.

PATIENTS AND METHODS

In this single-center retrospective study, conducted over 9 years (2011 to 2020), patients with stage II to III rectal cancer who had received NCRT were enrolled. The standard radiotherapy was 45 Gy to the pelvis, with a simultaneous integrated 50 Gy boost to the primary tumor. Continuous 5-Fluorouracil or oral capecitabine was administered concurrently. Surgery was preplanned within 6 to 8 weeks. Multinomial logistic regressions for evaluation of clinical factors, Kaplan-Meier method for DFS estimation, and receiver operating characteristic analysis for determination of the optimal timeframe were used.

RESULTS

Of 279 cases, pCR was observed in 72 (25.8%). In 207 cases, pTis-4N-negative was obtained in 137 (66.2%), pT0N-positive in 6 (2.9%), and pTis-4N-positive in 64 (30.9%). The pCR group had shorter diagnosis-NCRT time (P<0.01) and on-treatment time (P=0.05). DFS was longer for pCR and partial responders with clinical stage II and III (P<0.0001). Diagnosis-NCRT time was shown different between pCR and non-pCR groups. receiver operating characteristic analysis (P<0.01) showed that a diagnosis-NCRT time of <4.5 weeks predicts pCR with a sensitivity of 88% and specificity of 81% accuracy.

CONCLUSION

The time elapsed between rectal cancer diagnosis and NCRT initiation is significantly associated with pCR. Reducing this time may increase the probability of achieving pCR.

[Influence of molecular markers on oncological surgery of colorectal cancer]

Colorectal cancer (CRC) is still a very common disease and one of the best characterized malignancies on a molecular level. Interdisciplinary and multimodal treatment strategies should be preferred. In addition to surgical resection in localized stages as well as metastasectomy for oligometastatic advanced stages, neoadjuvant chemoradiotherapy for localized rectal cancer and cytostatic treatment, targeted treatment approaches should also be considered. This overview presents established and novel prognostic and predictive molecular markers of (metastasized) CRC and describes these as targeted therapy options. The determination of high microsatellite instability (MSI-H) has a therapeutic influence when planning adjuvant therapy and also now in the treatment of metastatic CRC. Furthermore, circulating tumor DNA represents a promising marker with respect to a recurrence in early as well as in advanced stages of disease. In addition to the RAS and BRAF mutation status and the localization of the primary tumor, an MSI‑H is also important with respect to the treatment strategy and should be determined before initiation of first-line treatment in metastasized CRC. New pharmaceutical approaches enable targeted interventions at the immunological or molecular level. The understanding of CRC as a heterogeneous disease has been increased using recently established analyses at the molecular level; however, it also generated many hypotheses that require further evaluation with respect to their clinical importance. Special attention is paid to patients affected by hereditary syndromes because of the early onset of disease and the considerable consequences individually and for the patient's family.

The Use of Single-Agent Versus Multiple-Agent Concurrent Chemoradiotherapy in the Treatment of Locally Advanced Rectal Cancer

PURPOSE

The use of concurrent chemoradiotherapy is frequently recommended in the treatment of locally advanced rectal cancer; however, the ideal chemotherapy regimen remains unknown, and there is variability in chemotherapy agents used among different institutions. We sought to examine differences in overall survival between patients receiving single versus multiple-agent concurrent chemoradiotherapy.

METHODS

The National Cancer Database was used to identify 31,025 patients with rectal cancer who received concurrent chemoradiotherapy between 01/2006 and 12/2016. We compared patients who received single-agent chemotherapy with those who received multiple-agent concurrent chemoradiotherapy. The primary outcome of interest was overall survival. The groups were compared using univariate analysis and Cox proportional hazard models to adjust for potential confounding factors.

RESULTS

18,544 patients received single-agent and 12,481 patients received multiple-agent chemotherapy. The former were older with more comorbidities as evidenced by their higher Charlson-Deyo Scores. Those receiving multiple-agent chemotherapy were more likely to have clinical stage III disease (52.9% vs 43.3%, p < 0.001) and less likely to have well-differentiated cancer (6.9% vs 7.7%, p < 0.001). The rates of negative resection margin were identical (p = 0.225) between the two groups. On multivariable analysis after adjusting for comorbidities, radiation dose, and resection margins, single-agent chemotherapy was associated with worse overall survival (HR 1.09, 95% CI 1.057-1.124, p < 0.001).

CONCLUSION

Multiple-agent chemoradiotherapy is associated with improved overall survival in locally advanced rectal cancer; however, chemotherapy regimen does not affect resection margins. The modest overall survival benefit with multiple-agent chemotherapy must be balanced with the potential associated toxicity.

Characteristics of Patients Presented With Metastases During or After Completion of Chemoradiation Therapy for Locally Advanced Rectal Cancer: A Case Series

PURPOSE

Locally advanced rectal cancer (LARC) is managed by chemoradiotherapy (CRT), followed by surgery. Herein we reported patients with metastases during or after CRT.

METHODS

Data of patients with LARC who received CRT from 2008 to 2017 were reviewed. Patients with metastases after CRT were included. Those with metastatic tumors at the initial diagnosis were excluded.

RESULTS

Fourteen patients (1.3%) of 1,092 who received CRT presented with metastases. Magnetic resonance circumferential resection margin (mrCRM) and mesorectal lymph nodes (LNs) were positive in 12 patients (85.7%). Meanwhile, magnetic resonance extramural vascular invasion (mrEMVI) was positive in 10 patients (71.4%). Magnetic resonance tumor regression grade (mrTRG) 4 and mrTRG5 was detected in 5 and 1 patient respectively. Ten patients (71.4%) underwent combined surgery and 3 (21.4%) received palliative chemotherapy.

CONCLUSION

Patients with metastases after CRT showed a higher rate of positive mrCRM, mrEMVI, mesorectal LNs, and poor tumor response. Further studies with a large number of patients are necessary for better survival outcomes in LARC.

Factors affecting pathological response and survival following neoadjuvant chemoradiotherapy in rectal cancer patients

Background

Despite all advanced treatment methods for rectal cancer, not all patients can provide an adequate response, and hence, possible prognostic factors must be evaluated. The aim of this study was to evaluate the relationship between systemic inflammatory markers and pathological response, overall survival (OS) and disease-free survival (DFS) in patients treated with neoadjuvant chemoradiotherapy (nCRT).

Methods

We evaluated data of 117 patients for the period 2010 to 2017. Serum measurements of albumin, hemoglobin, C-reactive protein, modified Glasgow prognostic score (mGPS), and white cell counts were obtained. Rodel scoring system was used to determine pathologic tumor regression.

Results

Overall, 77% of the patients were in the good response group according to the radiological images. A total of 48% of patients were categorized as a good pathologic response. Pathologic response to treatment was associated with a mGPS of 0 (P = 0.001), normal platelet lymphocyte ratio (PLR) (P = 0.003), TNM stage (P = 0.03), pathologic T stage (P = 0.001), radiologic response to nCRT (P = 0.04), tumor differentiation (P = 0.001), lymphovascular invasion (LVI) (P = 0.001) and perineural invasion (P = 0.02). LVI (P = 0.04), albumin level (P = 0.05), C-reactive protein (P = 0.01), neutrophil platelet score (NPS) (P = <0.001) and mGPS (P = 0.01) had a statistically significant effect on OS. Operation type (P = 0.03), tumor differentiation (P = 0.01), depth of invasion (P = 0.03), NPS (P < 0.01), mGPS (P = 0.01), PLR (P = 0.004), neutrophil-lymphocyte ratio (P = 0.01) and LVI (P = 0.05) were statistically significant on DFS.

Conclusions

There was an association between systemic inflammatory markers and pathologic response and also, between OS and DFS. This study can be preliminary data for prospective controlled studies.

Assessment of the aggressiveness of rectal cancer using quantitative parameters derived from dual-energy computed tomography

PURPOSE

To evaluate the value of quantitative parameters derived from dual-energy computed tomography (DECT) in assessing the aggressiveness of rectal cancer.

MATERIALS AND METHODS

Seventy-eight patients with rectal cancers confirmed by pathology underwent contrasted DECT scans. The normalized iodine concentration (NIC) and normalized water concentration (NWC) of the tumor against artery and tumor sizes were measured. The quantitative parameters were compared and statistically analyzed between subgroups based on the following prognostic factors: pretreatment carcinoembryonic antigen (CEA) levels, mesorectal fascia (MRF) status, T stage (T1,2 and T3,4), N stage (N0 and N1,2), tumor differentiation grade (poor differentiation, poor-moderate differentiation, moderate differentiation, moderate-well differentiation, well differentiation), and extramural venous invasion.

RESULTS

The differences of NIC values between MRF-free and MRF-invaded groups (P = 0.042), between T2 and T3-4 stage groups (P = 0.044), between N0 and N+ (N1, 2) groups (P = 0.036), between poor differentiation group and other differentiated groups (P < 0.05)were respectively significant. No significant differences of NIC values existed between CEA level or extramural venous invasion subgroups. For NWC values and tumor sizes, there were no significant differences between subgroups based on the prognostic factors above all.

CONCLUSIONS

Higher NIC value is associated with a more aggressive tumor character. NIC value may have the potential to become an imaging biomarker of tumor aggressiveness.

A novel nanoparticle-based theranostic agent targeting LRP-1 enhances the efficacy of neoadjuvant radiotherapy in colorectal cancer

Neoadjuvant radiotherapy has become an important therapeutic option for colorectal cancer (CRC) patients, whereas complete tumor response is observed only in 20-30% patients. Therefore, the development of diagnostic probe for radio-resistance is important to decide an optimal treatment timing and strategy for radiotherapy-resistant CRC patients. In this study, using the patient-derived xenograft (PDX) mouse model established with a radio-resistant CRC tumor tissue, we found low-density lipoprotein receptor-related protein-1 (LRP-1) as a radio-resistant marker protein induced by initial-dose radiation in radio-resistant CRC tumors. Simultaneously, we discovered a LRP-1 targeting peptide in a radio-resistant CRC PDX through in vivo peptide screening. We next engineered the theranostic agent made of human serum albumin nanoparticles (HSA NPs) containing 5-FU for chemo-radiotherapy and decorating LRP-1-targeting peptide for tumor localization, Cy7 fluorophore for diagnostic imaging. The nanoparticle-based theranostic agent accurately targeted the tumor designated by LRP-1 responding radiation and showed dramatically improved therapeutic efficacy in the radio-resistant PDX model. In conclusion, we have identified LRP-1 as a signature protein of radio-resistant CRC and successfully developed LRP-1-targeting HSA-NP containing 5-FU that is a novel theranostic tool for both diagnostic imaging and neoadjuvant therapy of CRC patients. This approach is clinically applicable to improve the effectiveness of neo-adjuvant radiotherapy and increase the ratio of complete tumor response in radio-resistant CRC.

Knowledge-based automatic optimization of adaptive early-regression-guided VMAT for rectal cancer

PURPOSE

To implement a knowledge-based (KB) optimization strategy to our adaptive (ART) early-regression guided boosting technique in neo-adjuvant radio-chemotherapy for rectal cancer.

MATERIAL AND METHODS

The protocol consists of a first phase delivering 27.6 Gy to tumor/lymph-nodes (2.3 Gy/fr-PTV₁), followed by the ART phase concomitantly delivering 18.6 Gy (3.1 Gy/fr) and 13.8 Gy (2.3 Gy/fr) to the residual tumor (PTV_ART) and to PTV₁ respectively. PTV_ART is obtained by expanding the residual GTV, as visible on MRI at fraction 9. Forty plans were used to generate a KB-model for the first phase using the RapidPlan tool. Instead of building a new model, a robust strategy scaling the KB-model to the ART phase was applied. Both internal and external validation were performed for both phases: all automatic plans (RP) were compared in terms of OARs/PTVs parameters against the original plans (RA).

RESULTS

The resulting automatic plans were generally better than or equivalent to clinical plans. Of note, V_30Gy and V_40Gy were significantly improved in RP plans for bladder and bowel; gEUD analysis showed improvement for KB-modality for all OARs, up to 3 Gy for the bowel.

CONCLUSIONS

The KB-model generated for the first phase was robust and it was also efficiently adapted to the ART phase. The performance of automatically generated plans were slightly better than the corresponding manual plans for both phases.

Impact of age on the efficacy of oxaliplatin in the preoperative chemoradiotherapy and adjuvant chemotherapy of rectal cancer: a post hoc analysis of the CAO/ARO/AIO-04 phase III trial

Background

The German rectal cancer trial CAO/ARO/AIO-04 has shown a significant benefit in 3-year disease-free survival (DFS) of adding oxaliplatin to a standard preoperative 5-fluorouracil (5-FU)-based chemoradiotherapy (CRT) and adjuvant chemotherapy in patients with locally advanced rectal cancer. The use of oxaliplatin as adjuvant treatment in elderly patients with colon cancer is controversial. We therefore investigated the impact of age on clinical outcome in the CAO/ARO/AIO-04 phase III trial.

Patients and methods

We carried out a post hoc analysis of the CAO/ARO/AIO-04 phase III trial evaluating primary and secondary end points according to age. Patient and tumor characteristics, NCI CTC adverse events grades 3-4 (version 3.0), dose intensities as well as survival and recurrence data were analyzed in three specified age groups (<60, 60-70, and ≥70 years). The influence of age as a continuous variable on DFS was modeled using a subpopulation treatment effect pattern plot (STEPP) analysis.

Results

A total of 1232 patients were assessable. With the exception of Eastern Cooperative Oncology Group status (P < 0.001), no differences in patient and tumor characteristics were noticed between age groups. Likewise, toxicity pattern, dose intensities of CRT and surgical results were similar in all age groups. After a median follow-up of 50 months, in patients aged <60 years a significant benefit of adding oxaliplatin to 5-FU-based CRT and adjuvant chemotherapy was observed for local (P = 0.013) and systemic recurrences (P = 0.023), DFS (P = 0.011), and even overall survival (OS; P = 0.044). The STEPP analysis revealed improved hazard ratios for DFS in patients aged 40-70 years compared with elderly patients treated with oxaliplatin.

Conclusion

The addition of oxaliplatin significantly improved DFS and OS in younger patients aged <60 years with advanced rectal cancer. Patients aged ≥70 years had no benefit.

Clinical Trials Number

NCT00349076.

Combined targeting of HER-2 and HER-3 represents a promising therapeutic strategy in colorectal cancer

Background

Abrogation of growth factor-dependent signaling represents an effective therapeutic strategy for patients with colorectal cancer (CRC). Here we evaluated the effectiveness of targeting the epidermal growth factor (EGF) receptors HER-2 and HER-3 in the three cell lines LS513, LS1034 and SW837.

Methods

Treatment with HER-2-specific antibodies trastuzumab and pertuzumab resulted in a mild reduction of cellular viability. In contrast, the antibody-drug conjugate T-DM1 mediated a strong and dose-dependent decrease of viability and Akt phosphorylation.

Results

The most striking effects were observed with the dual tyrosine kinase inhibitor lapatinib, and the Pan-ErbB inhibitor afatinib. Selectively, the effect of EGF receptor inhibition was augmented by a combination with 5-fluorouracil and oxaliplatin. Finally, high expression of HER-3 was detected in 121 of 172 locally advanced rectal cancers (70.3%). In conclusion, inhibition of EGF receptors effectively blocks downstream signaling and significantly impairs viability of CRC cells. However, the effectiveness of receptor inhibition highly depends on the inhibitors’ mode of action, as targeting HER-2 alone is not sufficient.

Conclusion

Since HER-2 and HER-3 are expressed in a relevant number of patients, targeting both receptors may represent a promising therapeutic strategy for CRC.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6051-0) contains supplementary material, which is available to authorized users.

Emerging strategies in the initial management of locally advanced rectal cancer

The initial management of locally advanced rectal cancer continues to evolve and formulating the ideal treatment plan remains challenging, with a multitude of emerging treatment strategies and either limited or inconsistent data to support these. The main objective of neoadjuvant treatment is to maximize disease control and minimize toxicity and impact on quality of life. Ultimately, the optimal approach needs to be personalized to the individual. In this Review, we discuss the various strategies currently used and being further investigated in the initial treatment of patients presenting with locally advanced rectal cancer. We describe the evidence behind the current standard of care recommendations and emerging new options, as well as potential biomarkers that may assist with further refining treatment selection.

Intraoperative intraperitoneal chemotherapy increases the incidence of anastomotic leakage after anterior resection of rectal tumors

BACKGROUND

Intraoperative intraperitoneal chemotherapy is an emerging treatment modality for locally advanced rectal neoplasms. However, its impacts on postoperative complications remain unknown. Anastomotic leakage (AL) is one of the most common and serious complications associated with the anterior resection of rectal tumors. Therefore, we designed this study to determine the effects of intraoperative intraperitoneal chemotherapy on AL.

AIM

To investigate whether intraoperative intraperitoneal chemotherapy increases the incidence of AL after the anterior resection of rectal neoplasms.

METHODS

This retrospective cohort study collected information from 477 consecutive patients who underwent an anterior resection of rectal carcinoma using the double stapling technique at our institution from September 2016 to September 2017. Based on the administration of intraoperative intraperitoneal chemotherapy or not, the patients were divided into a chemotherapy group (171 cases with intraperitoneal implantation of chemotherapy agents during the operation) or a control group (306 cases without intraoperative intraperitoneal chemotherapy). Clinicopathologic features, intraoperative treatment, and postoperative complications were recorded and analyzed to determine the effects of intraoperative intraperitoneal chemotherapy on the incidence of AL. The clinical outcomes of the two groups were also compared through survival analysis.

RESULTS

The univariate analysis showed a significantly higher incidence of AL in the patients who received intraoperative intraperitoneal chemotherapy, with 13 (7.6%) cases in the chemotherapy group and 5 (1.6%) cases in the control group (P = 0.001). As for the severity of AL, the AL patients who underwent intraoperative intraperitoneal chemotherapy tended to be more severe cases, and 12 (92.3%) out of 13 AL patients in the chemotherapy group and 2 (40.0%) out of 5 AL patients in the control group required a secondary operation (P = 0.044). A multivariate analysis was subsequently performed to adjust for the confounding factors and also showed that intraoperative intraperitoneal chemotherapy increased the incidence of AL (odds ratio = 5.386; 95%CI: 1.808-16.042; P = 0.002). However, the survival analysis demonstrated that intraoperative intraperitoneal chemotherapy could also improve the disease-free survival rates for patients with locally advanced rectal cancer.

CONCLUSION

Intraoperative intraperitoneal chemotherapy can improve the prognosis of patients with locally advanced rectal carcinoma, but it also increases the risk of AL following the anterior resection of rectal neoplasms.

Accurate outcome prediction after neo-adjuvant radio-chemotherapy for rectal cancer based on a TCP-based early regression index

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A TCP-based early regression index (ERI_TCP) was previously introduced.

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ERI_TCP was associated to improved survival after neo-adjuvant therapy for rectal cancer.

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Distant-metastasis-free survival was predicted by ERI_TCP and 5-FU dose.

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The resulting AUC (0.86) was significantly higher than models not including T ERI_TCP.

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ERI_TCP is a promising tool for therapy personalization.

Background and purpose

An early tumor regression index (ERI_TCP) was previously introduced and found to predict pathological response after neo-adjuvant radio-chemotherapy of rectal cancer. ERI_TCP was tested as a potential biomarker in predicting long-term disease-free survival.

Materials and methods

Data of 65 patients treated with an early regression-guided adaptive boosting technique (ART) were available. Overall, loco-regional relapse-free and distant metastasis-free survival (OS, LRFS, DMFS) were considered. Patients received 41.4 Gy in 18 fractions (2.3 Gy/fr), including ART concomitant boost on the residual GTV during the last 6 fractions (3 Gy/fr, D_mean: 45.6 Gy). Chemotherapy included oxaliplatin and 5-fluorouracil (5-FU). T2-weighted MRI taken before (MRI_pre) and at half therapy (MRI_half) were available and GTVs were contoured (V_pre, V_half). The parameter ERI_TCP = −ln[(1 − (V_half/V_pre))^Vpre] was calculated for all patients. Cox regression models were assessed considering several clinical and histological variables. Cox models not including/including ERI_TCP (CONV_model and REGR_model respectively) were assessed and their discriminative power compared.

Results

At a median follow-up of 47 months, OS, LRFS and DMFS were 94%, 95% and 78%. Due to too few events, multivariable analyses focused on DMFS: the resulting CONV_model included pathological complete remission or clinical complete remission followed by surgery refusal (HR: 0.15, p = 0.07) and 5-FU dose >90% (HR: 0.29, p = 0.03) as best predictors, with AUC = 0.75. REGR_model included ERI_TCP (HR: 1.019, p < 0.0001) and 5-FU dose >90% (HR: 0.18, p = 0.005); AUC was 0.86, significantly higher than CONV_model (p = 0.05). Stratifying patients according to the best cut-off value for ERI_TCP and to 5-FU dose (> vs <90%) resulted in 47-month DMFS equal to 100%/69%/0% for patients with two/one/zero positive factors respectively (p = 0.0002). ERI_TCP was also the only variable significantly associated to OS (p = 0.01) and LRFS (p = 0.03).

Conclusion

ERI_TCP predicts long-term DMFS after radio-chemotherapy for rectal cancer: an independent impact of the 5-FU dose was also found. This result represents a first step toward application of ERI_TCP in treatment personalization: additional confirmation on independent cohorts is warranted.

Randomized Phase II Trial of Chemoradiotherapy Plus Induction or Consolidation Chemotherapy as Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer: CAO/ARO/AIO-12

PURPOSE

Total neoadjuvant therapy is a new paradigm for rectal cancer treatment. Optimal scheduling of preoperative chemoradiotherapy (CRT) and chemotherapy remains to be established.

PATIENTS AND METHODS

We conducted a multicenter, randomized, phase II trial using a pick-the-winner design on the basis of the hypothesis of an increased pathologic complete response (pCR) of 25% after total neoadjuvant therapy compared with standard 15% after preoperative CRT. Patients with stage II or III rectal cancer were assigned to group A for induction chemotherapy using three cycles of fluorouracil, leucovorin, and oxaliplatin before fluorouracil/oxaliplatin CRT (50.4 Gy) or to group B for consolidation chemotherapy after CRT. Secondary end points included toxicity, compliance, and surgical morbidity.

RESULTS

Of the 311 patients enrolled, 306 patients were evaluable (156 in group A and 150 in group B). CRT-related grade 3 or 4 toxicity was lower (37% v 27%) and compliance with CRT higher in group B (91%, 78%, and 76% v 97%, 87%, and 93% received full-dose radiotherapy, concomitant fluorouracil, and concomitant oxaliplatin in groups A and B, respectively); 92% versus 85% completed all induction/consolidation chemotherapy cycles, respectively. The longer interval between completion of CRT and surgery in group B (median 90 v 45 days in group A) did not increase surgical morbidity. A pCR in the intention-to-treat population was achieved in 17% in group A and in 25% in group B. Thus, only group B (P < .001), but not group A (P = .210), fulfilled the predefined statistical hypothesis.

CONCLUSION

Up-front CRT followed by chemotherapy resulted in better compliance with CRT but worse compliance with chemotherapy compared with group A. Long-term follow-up will assess whether improved pCR in group B translates to better oncologic outcome.

Piperlongumine increases sensitivity of colorectal cancer cells to radiation: Involvement of ROS production via dual inhibition of glutathione and thioredoxin systems

Piperlongumine (PL), naturally synthesized in long pepper, is known to selectively kill tumor cells via perturbation of reactive oxygen species (ROS) homeostasis. ROS are the primary effector molecules of radiation, and increase of ROS production by pharmacological modulation is known to enhance radioresponse. We therefore investigated the radiosensitizing effect of PL in colorectal cancer cells (CT26 and DLD-1) and CT26 tumor-bearing mice. Firstly, we found that PL induced excessive production of ROS due to depletion of glutathione and inhibition of thioredoxin reductase. Secondly, PL enhanced both the intrinsic and hypoxic radiosensitivity of tumor cells, linked to ROS-mediated increase of DNA damage, G2/M cell cycle arrest, and inhibition of cellular respiration. Finally, the radiosensitizing effect of PL was verified in vivo. PL improved the tumor response to both single and fractionated radiation, resulting in a significant increase of survival rate of tumor-bearing mice, while it was ineffective on its own. In line with in vitro findings, enhanced radioresponse is associated with inhibition of antioxidant systems. In conclusion, our results suggest that PL could be a potential radiosensitizer in colorectal cancer.

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.

Phase I study of preoperative chemoradiotherapy with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer

The present study designed a novel preoperative chemoradiotherapy (CRT) with sequential oxaliplatin and irinotecan with S-1 for locally advanced rectal cancer (LARC). This phase I study evaluated the maximum tolerated dose and recommended dose (RD) of oxaliplatin following irinotecan with S-1. Patients with clinical stage T3 or 4 or involvement of the regional nodes and no evidence of distant metastases were treated with fixed doses of S-1 (80 mg/m²/day) on days 1-5, 8-12, 15-19, 22-27 and 29-33, and irinotecan (40 mg/m²/day) on days 1 and 8, followed by oxaliplatin on days 22 and 29. The dose of oxaliplatin was initially 40 mg/m² (level 1) with a predefined dose escalation schedule. The radiation dose was 1.8 Gy/fraction to a total dose of 45 Gy. A total of 9 patients were enrolled in the present study and 7 patients completely received CRT with this study protocol. The maximum tolerated dose for oxaliplatin was 50 mg/m² (level 2). Three of four patients experienced dose-limiting toxicity (grade 3 diarrhea) in oxaliplatin phase of level 2 dose. The RD of oxaliplatin was 40 mg/m² (level 1 dose). In addition, 2 patients had pathological CR (28.5%). Novel preoperative CRT with sequential oxaliplatin and irinotecan with S-1 for LARC resulted in acceptable toxicity and promising efficacy. However, the RD of oxaliplatin was lower than in previous CRT studies that combined oxaliplatin with S-1. To administer higher oxaliplatin, we have planned a phase I trial of preoperative CRT with sequential oxaliplatin followed by irinotecan with S-1 for LARC.

Phospho-ERK levels as predictors for chemotherapy of rectal carcinoma

Treatment of rectal cancer has been vastly improved by advances in surgery and radiochemotherapy but remains an important cause of morbidity and mortality worldwide. A particular problem is the lack of predictive markers that can help to individualize treatment. The growth- and apoptosis-regulating signaling molecules ERK 1 and 2 are important to cancer growth and progression. They are activated through phosphorylation, which is initiated by a cascade involving the EGF receptor and RAS as upstream regulators. Moreover, in vitro studies indicate that phospho-ERKs interfere with 5-fluorouracil-based chemotherapy. Recently, we showed that high levels of phospho-ERKs in rectal cancer cells predict poor responses to neoadjuvant (preoperative) radiochemotherapy. We now report that preoperative phospho-ERK levels also can subdivide high-risk rectal cancer patients into a favorable and a poor prognostic group with respect to recurrence-free survival. Importantly, phospho-ERK levels were of predictive significance only in high-risk patients, who received adjuvant (postoperative) chemotherapy, but not in high-risk patients not receiving such therapy. Our results suggest that high cancer cell levels of phospho-ERK predict poor responsiveness to both preoperative and postoperative chemotherapy of rectal cancer.

[Evidence-based surgery of rectal cancer]

Over the past four decades, the treatment algorithms for rectal cancer have fundamentally changed, which resulted in a considerable improvement of oncological outcomes. In this context, the surgical concept of total mesorectal excision and the implementation of multimodal treatment strategies represent key milestones. These improvements were complemented by a standardized histopathological work-up of the surgical specimen and the introduction of high-resolution magnetic resonance imaging (MRI) diagnostics. In addition, novel surgical techniques have been introduced, such as laparoscopic and robotic rectal resection. Other technological innovations include intraoperative pelvic neuromonitoring and fluorescence imaging. This review highlights the current evidence for selected, sometimes controversially discussed principles of surgical treatment strategies in rectal cancer.

Nomograms for predicting pathological response to neoadjuvant treatments in patients with rectal cancer

BACKGROUND

In recent decades, neoadjuvant therapy (NT) has been the standardized treatment for locally advanced rectal cancer (LARC). Approximately 8%-35% of patients with LARC who received NT were reported to have achieved a complete pathological response (pCR). If the pathological response (PR) can be accurately predicted, these patients may not need surgery. In addition, no response after NT implies that the tumor is destructive, resistant to both chemotherapy and radiotherapy, and prone to having a high metastatic potential. Therefore, developing accurate models to predict PR has great clinical significance and can help achieve individualized treatment in LARC patients.

AIM

To establish nomograms for predicting PR to different NT regimens based on pretreatment parameters for patients with LARC.

METHODS

Rectal cancer patients were identified from the database of The Sixth Affiliated Hospital, Sun Yat-sen University from January 2012 to December 2016. Logistic regression and nomograms were developed to predict the probability of pCR and good downstaging to ypT0-2N0M0 (ypTNM 0-I), respectively, based on pretreatment parameters for all LARC patients. Nomograms were also developed for three NT regimens (capecitabine/deGramont-RT, mFOLFOX6, and mFOLFOX6-RT) to predict pCR probability.

RESULTS

Four hundred and three patients were included in this study; 72 (17.9%) had pCR at the final pathology report, and 177 (43.9%) achieved good downstaging to ypT0-2N0M0 (ypTNM 0-I). The nomogram for predicting pCR probability showed that NT regimens, tumor differentiation, mesorectal fascia (MRF) status, and tumor length significantly influenced pCR probability. When predicting the probability of good downstaging, tumor differentiation, MRF status, and clinical T stage were the significant factors. Nomograms were developed based on NT regimens. For the capecitabine/de Gramont-RT group, the multivariate analysis showed that the neutrophil-lymphocyte ratio (NLR) was the only significant factor, thus we could not develop a nomogram for this regimen. For the mFOLFOX6-RT group, the analysis showed that the significant factors were tumor length and MRF status; and for the mFOLFOX6 group, the significant factors were tumor length and tumor differentiation.

CONCLUSION

We established accurate nomograms for predicting the PR to preoperative NT regimens based on pretreatment parameters for LARC patients.

Recent advances of neoadjuvant chemoradiotherapy in rectal cancer: Future treatment perspectives

Neoadjuvant chemoradiotherapy (nCRT) has been widely used as a multidisciplinary approach for stage II/III rectal cancer. However, its safety and efficacy are controversial because previous studies have shown conflicting outcomes. The present review aimed to elucidate the benefits and limitations of nCRT for patients with rectal cancer. Future perspectives of nCRT are also described. No recent randomized trials have been able to show a survival benefit, although many studies have demonstrated good local control with the use of fluoropyrimidine (e.g. 5-fluorouracil [FU] or capecitabine)-based nCRT. Addition of oxaliplatin (OX) to FU-based nCRT might improve overall survival by preventing distant metastasis, as shown in recent meta-analyses. However, control of adverse effects is an important concern with this treatment. New treatment strategies such as nonoperative management (watch and wait policy) and total neoadjuvant therapy (TNT) are promising, but the establishment of reliable diagnostic methods of metastasis is essential. Development of new biomarkers is also necessary to select patients who are more likely to benefit from nCRT.

Expression of guanylyl cyclase C in tissue samples and the circulation of rectal cancer patients

Guanylyl cyclase C (GCC) is a transmembrane surface receptor restricted to intestinal epithelial cells, from the duodenum to the rectum. We compared GCC expression in tumors and normal rectal tissues, and investigated the relation between GCC expression and metastasis and long-term survival of rectal cancer patients. Based on the UICC classification, 42 rectal cancer patients in this study were classified as stage I, 48 patients as stage II, and 90 patients as stage III. Overexpression of GCC was observed in 80 rectal tumors as compared to matched normal tissues, where no strong staining of GCC was observed. An association between GCC mRNA in the circulation and tumor emboli in vessels, CK20 mRNA, distant organ metastasis, and survival status was observed in 100 rectal cancer patients. Univariate Cox regression analysis indicated that tumor emboli in vessels, lymph node metastasis, mesenteric root lymph node metastasis and GCC mRNA correlated with 5-year disease-free survival (DFS); while lymph node metastasis, GCC mRNA, and CK20 mRNA strongly correlated with 5-year overall survival (OS). In a multivariate Cox regression model, GCC mRNA level and mesenteric root lymph node metastasis associated with DFS, while GCC mRNA levels associated with OS. Quantification of GCC expression in circulation is a valuable biomarker for assessing tumor burden and predicting outcome in rectal cancer patients.

Potential of memory T cells in bridging preoperative chemoradiation and immunotherapy in rectal cancer

The management of locally advanced rectal cancer has passed a long way of developments, where total mesorectal excision and preoperative radiotherapy are crucial to secure clinical outcome. These and other aspects of multidisciplinary strategies are in-depth summarized in the literature, while our mini-review pursues a different goal. From an ethical and medical standpoint, we witness a delayed implementation of novel therapies given the cost/time consuming process of organizing randomized trials that would bridge an already excellent local control in cT3-4 node-positive disease with long-term survival. This unfortunate separation of clinical research and medical care provides a strong motivation to repurpose known pharmaceuticals that suit for treatment intensification with a focus on distant control. In the framework of on-going phase II-III IG/IMRT-SIB trials, we came across an intriguing translational observation that the ratio of circulating (protumor) myeloid-derived suppressor cells to (antitumor) central memory CD8+ T cells is drastically increased, a possible mechanism of tumor immuno-escape and spread. This finding prompts that restoring the CD45RO memory T-cell pool could be a part of integrated adjuvant interventions. Therefore, the immunocorrective potentials of modified IL-2 and the anti-diabetic drug metformin are thoroughly discussed in the context of tumor immunobiology, mTOR pathways and revised Warburg effect.

Application value of biplane transrectal ultrasonography plus ultrasonic elastosonography and contrast-enhanced ultrasonography in preoperative T staging after neoadjuvant chemoradiotherapy for rectal cancer

PURPOSE

To determine the accuracy of biplane transrectal ultrasonography (TRUS) plus ultrasonic elastosonography (UE) and contrast-enhanced ultrasonography (CEUS) in preoperative T staging after neoadjuvant chemoradiotherapy for rectal cancer.

MATERIALS AND METHODS

Fifty-three patients with advanced lower rectal cancer were examined before and after neoadjuvant chemoradiotherapy with use of TRUS plus UE and CEUS and were diagnosed as having T stage disease. We compared ultrasonic T stages before and after neoadjuvant chemoradiotherapy and analyzed any changes. Also, with postoperative pathological stages as the gold standard, we compared ultrasonic and pathological T stages and determined their consistency by the kappa statistic.

RESULTS

For patients with rectal cancer, ultrasonic T stages were lower after neoadjuvant chemoradiotherapy than before, with a statistically significant difference (P < 0.05). The posttreatment downstaging rate was 39.6% (21/53). A total of 84.9% received correct staging with use of biplane TRUS plus UE and CEUS in the evaluation of preoperative T staging after neoadjuvant chemoradiotherapy for rectal cancer, which was highly consistent with that of pathological staging (κ = 0.768, P < 0.05). Its sensitivities were 80.0%, 50.0%, 75.0%, 96.3%, and 100% in the diagnoses of stages T0 to T4 rectal cancers, respectively; the specificities were 95.4%, 97.9%, 95.1%, 88.5%, and 100% at stages T0 to T4, respectively.

CONCLUSION

Biplane TRUS plus UE and CEUS can be used to accurately perform preoperative T staging in rectal cancer after neoadjuvant chemoradiotherapy; in addition, this procedure well reflects changes in depth of rectal cancer invasion into the intestinal wall before and after neoadjuvant chemoradiotherapy. It is of great value in clinically evaluating the efficacy of neoadjuvant chemoradiotherapy, in selecting therapeutic regimens, and in avoiding overtreatment.

Influence of complete administration of adjuvant chemotherapy cycles on overall and disease-free survival in locally advanced rectal cancer: post hoc analysis of a randomized, multicenter, non-inferiority, phase 3 trial

Background

A randomized trial demonstrated that capecitabine is at least as effective as fluorouracil in the adjuvant treatment of patients with locally advanced rectal cancer. However, not all patients receive all planned cycles of chemotherapy. Therefore it is of interest how complete or partial administration of chemotherapy influences oncological outcome.

Methods

A post hoc analysis of a trial with 401 randomized patients, nine being excluded because of missing data, was performed. 392 patients (197 - capecitabine, 195 - fluorouracil) could be analyzed regarding the number of administered adjuvant chemotherapy cycles. In the subgroup of 361 patients with an overall survival of at least six months, five-year overall and disease-free survival were analyzed in respect to completion (complete vs. incomplete) of chemotherapy cycles. Survival rates and curves were calculated and compared using the log-rank test. The effect of completion of chemotherapy was adjusted for relevant confounding factors.

Results

Two hundred fifty-one (64.0%) of analyzed patients received all postoperative scheduled cycles. Five-year overall survival was significantly better in these patients compared to the incomplete group (76.0 vs. 60.6%, p < 0.0001). Of 361 patients with an overall survival of at least six months, 251(69.5%) patients received all cycles. Five-year overall survival was also significantly better than in the incomplete group (76.0 vs. 66.4%, p = 0.0073). Five-year disease free survival was numerically better (64.9 vs. 58.7%, p = 0.0646; HR [not all cycles vs. all cycles] = 1.42 95% CI: [0.98, 2.07]). Cox regression models show a non-significant better OS (p = 0.061) and DFS (p = 0.083), if chemotherapy cycles were administered completely.

Conclusion

Complete administration of chemotherapy cycles was associated with improved five-year overall and disease-free survival in patients with locally advanced rectal cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4309-6) contains supplementary material, which is available to authorized users.

RBBP6 increases radioresistance and serves as a therapeutic target for preoperative radiotherapy in colorectal cancer

Radiotherapy (RT) can be used as preoperative treatment to downstage initially unresectable locally rectal carcinoma, but radioresistance and recurrence remain significant problems. Retinoblastoma binding protein 6 (RBBP6) has been implicated in the regulation of cell cycle, apoptosis and chemoresistance both in vitro and in vivo. The present study investigated whether the inhibition of RBBP6 expression would improve radiosensitivity in human colorectal cancer cells. After SW620 and HT29 cells were exposed to radiation, the levels of RBBP6 mRNA and protein increased over time in both cells. Moreover, a significant reduction in clonogenic survival and a decrease in cell viability in parallel with an obvious increase in cell apoptosis were demonstrated in irradiated RBBP6‐knockdown cells. Transfection with RBBP6 shRNA improved the levels of G2‐M phase arrest, which blocked the cells in a more radiosensitive period of the cell cycle. These observations indicated that cell cycle and apoptosis mechanisms may be connected with tumor cell survival following radiotherapy. In vivo, the tumor growth rate of nude mice in the RBBP6‐knockdown group was significantly slower than that in other groups. These results indicated that RBBP6 overexpression could resist colorectal cancer cells against radiation by regulating cell cycle and apoptosis pathways, and inhibition of RBBP6 could enhance radiosensitivity of human colorectal cancer.

Contemporary management of locally advanced rectal cancer: Resolving issues, controversies and shifting paradigms

Advancements in rectal cancer treatment have resulted in improvement only in locoregional control and have failed to address distant relapse, which is the predominant mode of treatment failure in rectal cancer. As the efficacy of conventional chemoradiotherapy (CRT) followed by total mesorectal excision (TME) reaches a plateau, the need for alternative strategies in locally advanced rectal cancer (LARC) has grown in relevance. Several novel strategies have been conceptualized to address this issue, including: 1) neoadjuvant induction and consolidation chemotherapy before CRT; 2) neoadjuvant chemotherapy alone to avoid the sequelae of radiation; and 3) nonoperative management for patients who achieved pathological or clinical complete response after CRT. This article explores the issues, recent advances and paradigm shifts in the management of LARC and emphasizes the need for a personalized treatment plan for each patient based on tumor stage, location, gene expression and quality of life.

Pathologic assessment of gastrointestinal tract and pancreatic carcinoma after neoadjuvant therapy

Neoadjuvant therapy is increasingly used to treat patients with a wide variety of malignancies. Histologic evaluation of treated specimens provides important prognostic information and may guide subsequent chemotherapy. Neoadjuvant therapy is commonly employed in the treatment of locally advanced rectal adenocarcinoma, hepatic colorectal metastases, esophageal/esophagogastric junction carcinoma, and pancreatic ductal adenocarcinoma. Numerous tumor regression schemes have been used in these tumors and standardized approaches to evaluate these specimens are needed. In this review, the various tumor regression scoring systems that have been used in these organs are described and their associations with clinical outcomes are discussed. Recommendations regarding how to handle and report the histologic findings in these resections specimens are provided.

Complete response after chemoradiotherapy for rectal cancer: what is the reasonable approach?

With the increasing use of preoperative treatment rather than upfront surgery, it has become evident that the response of rectal carcinoma to standard chemoradiotherapy (CRT) shows a great variety that includes histopathologiocally confirmed complete tumor regression in 10–30% of cases. Adaptive strategies to avoid radical surgery, either by local excision or non-operative management, have been proposed in these highly responsive tumors. A growing number of prospective clinical trials and experiences from large databases, such as the European Registration of Cancer Care (EURECCA) watch-and-wait database, or the recent Oncological Outcome after Clinical Complete Response in Patients with Rectal Cancer (OnCoRe) project, will provide more information on its safety and efficacy, and help to select appropriate patients. Future studies will have to establish appropriate inclusion criteria and optimize CRT regimens in order to maximize the number of patients achieving complete response. Standardized re-staging procedures have to be investigated to improve the prediction of a sustained complete response, and long-term close follow-up with thorough documentation of failure patterns and salvage therapies will have to prove the oncological safety of this approach.

The Addition of Target Therapy to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer: A Review

Currently, neoadjuvant fluoropyrimidine-based chemoradiotherapy (CRT) is standard practice in the management of locally advanced rectal cancer (LARC). In the last decade there has been a lively interest in the improvement of clinical outcomes by modifying this standard regimen by the addition of further agents. We review combinations of targeted therapies and conventional CRT currently under investigation in LARC patients.

Time to surgery and pathologic complete response after neoadjuvant chemoradiation in rectal cancer: A population study on 2094 patients

•

A large population based analysis to evaluate pathologic response according to time of surgery.

•

LARC patients were treated with modern techniques of radiotherapy and surgery.

•

The rate of pCR increased according to time interval from 12.6% to 31.1%.

•

The pCR increasing was 1.5% (about 0.2%/die) per each week of waiting.

•

Lengthening the interval (>13 weeks) significantly improved the pathological response.

Background

To retrospectively evaluate the difference in terms of pathologic complete response (pCR) according to time elapsed between chemoradiation (CRT) and total mesorectal excision (TME) on a large unselected real-life dataset of locally advanced rectal cancer (LARC) patients.

Methods

A multicentre retrospective cohort study of LARC patients from 21 Italian Radiotherapy Institutions was performed. Patients were stratified into 3 different time intervals from CRT. The 1st group included 300 patients who underwent TME within 6 weeks, the 2nd 1598 patients (TME within 7–12 weeks) and the 3rd 196 patients (TME within 13 or more weeks after CRT), respectively.

Results

Data on 2094 LARC patients treated between 1997 and 2016 were considered suitable for analysis. Overall, 578 patients had stage II while 1516 had stage III histological proven invasive rectal adenocarcinoma. A CRT schedule of one agent (N = 1585) or 2-drugs (N = 509) was administered. Overall, pCR was 22.3% (N = 468 patients). The proportion of patients achieving pCR with respect to time interval was, as follows: 12.6% (1st group), 23% (2nd group) and 31.1% (3rd group) (p < 0.001), respectively. The pCR relative risk comparison of 2nd to 1st group was 1.8, while 3rd to 2nd group was 1.3. Moreover, between the 3rd and 1st group, a pCR relative risk of 2.4 (p < 0.01) was noted. At univariate analysis, clinical stage III (p < 0.001), radiotherapy dose >5040 cGy (p = 0.002) and longer interval (p < 0.001) were significantly correlated to pCR. The positive impact of interval (p < 0.001) was confirmed at multivariate analysis as the only correlated factor.

Conclusion

We confirmed on a population-level that lengthening the interval (>13 weeks) from CRT to surgery improves the pathological response (pCR and pathologic partial response; pPR) in comparison to historic data. Furthermore, radiotherapy dose >5040 cGy and two drugs chemotherapy correlated with pPR rate.