Swedish Rectal Cancer Trial: long lasting benefits from radiotherapy on survival and local recurrence rate

Immune Checkpoint Inhibition as a Strategy in the Neoadjuvant Treatment of Locally Advanced Rectal Cancer

The treatment of locally advanced rectal cancer (LARC) has seen major advances over the past 3 decades, with multimodality treatment now standard of care. Combining surgical resection with radiotherapy and/or chemotherapy can reduce local recurrence from around 20% to approximately 5%. Despite improvements in local control, distant recurrence and subsequent survival rates have not changed. Immune checkpoint inhibitors have improved patient outcomes in several solid tumor types in the neoadjuvant, adjuvant, and advanced disease setting; however, in colorectal cancer, most clinical trials have been performed in the metastatic setting and the benefits confined to microsatellite instability-high tumors. In this article, we review the current preclinical and clinical evidence for using immune checkpoint inhibition in the treatment of LARC and discuss the rationale for specifically exploring the use of this therapy in the neoadjuvant setting. We summarize and discuss relevant clinical trials that are currently in setup and recruiting to test this treatment strategy and reflect on unanswered questions that still need to be addressed within future research efforts.

New treatment strategies for non-metastatic rectal cancer

The most widely practiced (standard) treatment of non-metastatic rectal cancer is based on proctectomy with mesorectal excision (partial or total according to the location of the tumor and commonly called TME). Surgery is preceded by CAP50-type chemoradiotherapy (capecitabineand 50 Grays radiation) and performed 6-8 weeks after the end of chemoradiotherapy. The development of new endoscopic, surgical, radiation-based and chemotherapeutic modalities leads surgeons to envisage customized treatment to find the best compromise between functional and oncologic results according to the locoregional extension of the tumor. Superficial lesions are amenable to transanal excision. T2-3 tumors<4cm are amenable to rectal preservation when neoadjuvant treatment obtains a complete response, allowing local excision or close surveillance. Intensification endocavitary radiotherapy and induction and consolidation chemotherapy regimens to avoid recourse to salvage abdomino-perineal resection (APR) are under investigation. For locally advanced rectal cancers (T3-4 and all N+ irrespective of T), the following scenarios can be envisaged: for initially resectable tumors (T3N0, T1-T3N+, circumferential resection margin>2mm), neoadjuvant chemotherapy alone aims to minimize the risk of local recurrence while avoiding the sequelae of radiotherapy. In case of initially non-resectable tumors (T4, circumferential resection margin<1mm), induction chemotherapy before chemoradiotherapy and consolidation chemotherapy after short course radiotherapy provide better results than standard treatment in terms of complete response and recurrence-free survival, and should be routinely proposed in this indication.

Evolution and Current Status of the Multidisciplinary Management of Locally Advanced Rectal Cancer

The management of locally advanced rectal cancer has grown in both complexity and quality since the first proctectomy. What once was a malignancy with a fairly consistent treatment algorithm for decades, a recent paradigm shift in the care of these patients has led to a more personalized, multidisciplinary approach with variations in timing, sequence, duration, and potential exclusion of multimodality therapies. This review summarizes the most important evidence behind these developing overarching concepts to provide a context for this paradigm shift.

Multi-parametric magnetic resonance imaging assessment of whole tumour heterogeneity for chemoradiotherapy response prediction in rectal cancer

Background and purpose

Prediction of chemoradiotherapy response (CRT) in locally advanced rectal cancer would enable stratification of management. The purpose was to prospectively evaluate multi-parametric magnetic resonance imaging (MRI) assessment of tumour heterogeneity combining diffusion weighted imaging (DWI) and dynamic contrast enhanced (DCE) MRI for the prediction of CRT response in locally advanced rectal cancer.

Materials and methods

Patients with Stage II or III rectal adenocarcinoma undergoing neoadjuvant CRT and surgery underwent MRI (DWI and DCE) before, during (week 3), and after CRT (1 week before surgery). Patients with histopathology tumour regression grade (TRG) 0-1 were classified as responders, and TRG 2-3 were classified as non-responders. A whole tumour voxel-wise technique was used to produce apparent diffusion coefficient (ADC) and K^trans (Tofts model) histograms derived from DWI and DCE-MRI, respectively. Logistic regression was used to predict response status for ADC and K^trans quantiles.

Results

Thirty-three patients were included in this analysis; 16 responders, and 17 non-responders. On heterogeneity analysis, odds of being a responder were significantly higher after CRT (before surgery) for higher ADC 75th (p = 0.049) and ADC 90th (p = 0.034) percentile values. The K^trans quantiles were lower in non-responders than responders before and during CRT, and higher after CRT although no significant association with response status was observed (p ≥ 0.10).

Conclusions

DWI-MRI after CRT (before surgery) incorporating a histogram analysis of whole tumour heterogeneity was predictive of CRT response in patients with locally advanced rectal cancer. DCE-MRI did not add value in response prediction.

Clinical trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR) number ACTRN12616001690448.

Emerging Trends for Radio-Immunotherapy in Rectal Cancer

Rectal cancer is a heterogeneous disease at the genetic and molecular levels, both aspects having major repercussions on the tumor immune contexture. Whilst microsatellite status and tumor mutational load have been associated with response to immunotherapy, presence of tumor-infiltrating lymphocytes is one of the most powerful prognostic and predictive biomarkers. Yet, the majority of rectal cancers are characterized by microsatellite stability, low tumor mutational burden and poor T cell infiltration. Consequently, these tumors do not respond to immunotherapy and treatment largely relies on radiotherapy alone or in combination with chemotherapy followed by radical surgery. Importantly, pre-clinical and clinical studies suggest that radiotherapy can induce a complete reprograming of the tumor microenvironment, potentially sensitizing it for immune checkpoint inhibition. Nonetheless, growing evidence suggest that this synergistic effect strongly depends on radiotherapy dosing, fractionation and timing. Despite ongoing work, information about the radiotherapy regimen required to yield optimal clinical outcome when combined to checkpoint blockade remains largely unavailable. In this review, we describe the molecular and immune heterogeneity of rectal cancer and outline its prognostic value. In addition, we discuss the effect of radiotherapy on the tumor microenvironment, focusing on the mechanisms and benefits of its combination with immune checkpoint inhibitors.

MRI-based nomogram analysis: recognition of anterior peritoneal reflection and its relationship to rectal cancers

Background

This study is aimed to explore the factors influencing the visualization of the anterior peritoneal reflection (APR) and evaluated the feasibility of measuring the distance from the anal verge to APR (AV-APR), the tumor height on MRI and the accuracy of determining the tumor location with regard to APR.

Methods

We retrospectively analyzed 110 patients with rectal cancer. A univariate and multivariate logistic regression was performed to identify the independent factors (age, sex, T stage, the degree of bladder filling, pelvic effusion, intraoperative tumor location, BMI, uterine orientation, the distance from seminal vesicle/uterus to rectum) associated with the visualization of the APR on MRI. The nomogram diagram and receiver operating characteristic curve (ROC curve) were established. Intraclass correlation coefficient (ICC) was used to evaluate the consistency of the distance of AV-APR. The Pearson correlation coefficient was used to characterize the agreement between measurements of the tumor height by colonoscopy and MRI. The Kappa statistics was used to evaluate the value of MRI in the diagnosis of the tumor location with regard to the APR.

Results

Multivariate logistic regression showed that BMI (P = 0.031, odds ratio, OR = 1.197), pelvic effusion (P = 0.020, OR = 7.107) and the distance from seminal vesicle/uterus to the rectum (P = 0.001, OR = 3.622) were correlated with the visualization of APR. The cut-off point of BMI and the distance from seminal vesicle/uterus to the rectum is 25.845 kg/m² and 1.15 cm. The area under curve (AUC) (95% Confidence Interval, 95% CI) of the combined model is 0.840 (0.750–0.930). The favorable calibration of the nomogram showed a non-significant Hosmer–Lemeshow test statistic (P = 0.195). The ICC value (95% CI) of the distance of AV-APR measured by two radiologists was 0.981 (0.969–0.989). The height measured by MRI and colonoscopy were correlated with each other (r = 0.699, P < 0.001). The Kappa value was 0.854.

Conclusions

BMI, pelvic effusion, and the distance from seminal vesicle/uterus to rectum could affect the visualization of APR on MRI. Also, it’s feasible to measure the distance of AV-APR, the tumor height, and to evaluate the tumor location with regard to APR using MRI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-021-00583-7.

Neoadjuvant Short-Course Radiotherapy for Upper Third Rectal Tumors: Systematic Review and Individual Patient Data Metaanalysis of Randomized Controlled Trials

BACKGROUND

There is no consensus on the use of neoadjuvant radiotherapy for tumors of the upper third of the rectum. Due to conflicting findings in high-quality trials and significant long-term side effects associated with neoadjuvant radiotherapy, the benefit of neoadjuvant radiotherapy for upper third rectal tumors is less certain than for lower two third rectal tumors. This metaanalysis compares oncological outcomes with neoadjuvant radiotherapy and surgery versus surgery alone for upper third rectal tumors.

PATIENTS AND METHODS

PubMed, Embase, and the Cochrane library databases were searched. Randomized controlled trials (RCT) comparing neoadjuvant radiotherapy and surgery versus surgery alone for resectable rectal cancer were included. Individual patient data were sought from the principal investigator of each eligible trial for comparative data on patients with upper third rectal tumors. The main outcomes measured were survival outcomes, oncological outcomes, postoperative morbidity, and late toxicity.

RESULTS

Individual patient data from two RCTs examining outcomes in 758 patients were obtained. Published data from one further RCT containing comparable data on upper third rectal tumors were included in analysis of local recurrence. In patients with curative surgery, there was no significant reduction in local recurrence or significant improvement in overall survival or disease-free survival with neoadjuvant radiotherapy (LR RR: 0.38, 95% CI 0.14-1.04, p = 0.06) (OS RR: 1.10, 95% CI 0.98-1.24, p = 0.11) (DFS RR: 1.11, 95% CI 0.97-1.26, p = 0.13).

CONCLUSIONS

The benefit of neoadjuvant radiotherapy for upper third rectal tumors is not certain, and surgery alone for patients with potentially curative disease at preoperative staging may be sufficient.

Clinical significance of CD8+ and FoxP3+ tumor-infiltrating lymphocytes and MFG-E8 expression in lower rectal cancer with preoperative chemoradiotherapy

Preoperative chemoradiotherapy (CRT) for rectal cancer contributes to tumor down-staging and decreases locoregional recurrence. However, each patient shows a significantly different response to CRT. Therefore, the identification of predictive factors to CRT response would be beneficial to avoid unnecessary treatment. Cancer immunity in patients has been suggested to play an important role in the eradication of the tumor by CRT. In the present study, the utility of CD8⁺ and forkhead box P3 (FoxP3)⁺ tumor-infiltrating lymphocytes (TILs) and the expression of a novel immuno-regulatory factor, lactadherin (MFG-E8), in predicting CRT effectiveness in patients with rectal cancer was examined. A total of 61 patients with rectal cancer, who underwent curative resection following CRT were included in the study. The numbers of CD8⁺ and FoxP3⁺ TILs in a biopsy taken before CRT and MFG-E8 expression level in the specimens obtained at the time of the surgery after CRT were examined using immunohistochemical staining, and their association with clinicopathological characteristics, including patient survival, was determined. The tumors with more CD8⁺ TILs in the biopsy samples before CRT showed a significantly more favorable CRT response. The patients with tumors and a higher number of CD8⁺ TILs before CRT also exhibited significantly longer disease-free and overall survival times. Higher MFG-E8 expression level in post-CRT specimens was significantly associated with favorable CRT response; however, no significant association was found with any other clinicopathological characteristics, including survival time. The number of CD8⁺ TILs before CRT was a valuable predictor for CRT response and was associated with favorable prognosis in patients with lower rectal cancer and who were treated with CRT. High MFG-E8 expression level after CRT was also associated with a favorable CRT response.

Which Definition of Upper Rectal Cancer Is Optimal in Selecting Stage II or III Rectal Cancer Patients to Avoid Postoperative Adjuvant Radiation?

BACKGROUND

In most guidelines, upper rectal cancers (URC) are not recommended to take neoadjuvant or adjuvant radiation. However, the definitions of URC vary greatly. Five definitions had been commonly used to define URC: 1) >10 cm from the anal verge by MRI; 2) >12 cm from the anal verge by MRI; 3) >10 cm from the anal verge by colonoscopy; 4) >12 cm from the anal verge by colonoscopy; 5) above the anterior peritoneal reflection (APR). We hypothesized that the fifth definition is optimal to identify patients with rectal cancer to avoid adjuvant radiation.

METHODS

The data of stage II/III rectal cancer patients who underwent radical surgery without preoperative chemoradiotherapy were retrospectively reviewed. The height of the APR was measured, and compared with the tumor height measured by digital rectal examination (DRE), MRI and colonoscopy. The five definitions were compared in terms of prediction of local recurrence, survival, and percentages of patients requiring radiation.

RESULTS

A total of 576 patients were included, with the intraoperative location of 222 and 354 tumors being above and straddle/below the APR, respectively. The median distance of the APR from anal verge (height of APR) as measured by MRI was 8.7 (range: 4.5-14.3) cm. The height of APR positively correlated with body height (r=0.862, P<0.001). The accuracy of the MRI in determining the tumor location with respect to the APR was 92.1%. Rectal cancer above the APR had a significantly lower incidence of local recurrence than those straddle/below the APR (P=0.042). For those above the APR, there was no significant difference in local recurrence between the radiation and no-radiation group. Multivariate analyses showed that tumor location regarding APR was an independent risk factor for LRFS. Tumor height as measured by DRE, MRI and colonoscopy were not related with survival outcomes. Fewer rectal cancer patients required adjuvant radiation using the definition by the APR, compared with other four definitions based on a numerical tumor height measured by MRI and colonoscopy.

CONCLUSIONS

The definition of URC as rectal tumor above the APR, might be the optimal definition to select patients with stage II/III rectal cancer to avoid postoperative adjuvant radiation.

Neoadjuvant Therapy for Locally Advanced Rectal Cancer: Recent Advances and Ongoing Challenges

Locally advanced rectal cancer has a rising global incidence. Over the last 4 decades, advances first in surgery and later in radiotherapy and chemoradiotherapy have improved outcomes, particularly with regard to local recurrence. Unfortunately, distant metastases remain a significant problem. In clinical trials of patients with stage II and III disease, distant relapse occurs in 25% to 30% of patients regardless of the treatment approach. Recent phase 3 trials have therefore focused on intensification of systemic therapy for localized disease, with an aim of reducing the distant relapse rate. Early results of trials of total neoadjuvant therapy with combination systemic therapy provided in the neoadjuvant setting are promising; for the first time, a significant improvement in the rate of distant relapse has been noted. Longer-term follow-up is eagerly awaited. On the other hand, trimodal therapy with chemotherapy, radiotherapy, and surgery is toxic. Several trials are currently assessing the feasibility of a watch-and-wait approach, omitting surgery in those with complete response to neoadjuvant treatment, in an attempt to reduce the burden of treatment on patients. The future for rectal cancer patients is likely to be highly personalized, with more intense approaches for high-risk patients and omission of unnecessary therapy for those whose disease responds well to initial treatment. Biomarkers such as circulating tumor DNA will help to more accurately stratify patients into risk groups. Improvements in survival and quality of life are expected as the results of ongoing research become available throughout the next decade.

Randomized phase II study comparing the efficacy and safety of SOX versus mFOLFOX6 as neoadjuvant chemotherapy without radiotherapy for locally advanced rectal cancer (KSCC1301)

BACKGROUND

Preoperative chemoradiotherapy (CRT), the current standard of care for locally advanced rectal cancer (LARC), is associated with many radiotherapy (RT)-related side effects. We aimed to evaluate whether S-1 and oxaliplatin (SOX) or folinic acid, 5-FU, and oxaliplatin (mFOLFOX6) can be as effective as neoadjuvant chemotherapy (NAC) regimens for LARC without RT.

METHODS

Patients with untreated resectable LARC were randomly assigned to receive SOX or mFOLFOX6. The NAC protocol period was 3 months. The primary endpoint was 3-year disease-free survival (DFS), and the secondary endpoints included pathological effects, surgical completion rate, 3-year survival, and safety.

RESULTS

From September 2013 to October 2015, 56 and 54 patients were enrolled in the SOX and mFOLFOX6 arms, respectively. The 3-year DFS rates were 69.4% (95% confidence interval [CI] 54.9-83.6) and 73.4% (95% CI 58.7-83.6) in the SOX and mFOLFOX6 arms, respectively; no significant differences were found between the arms (log-rank test; P = 0.5315, hazard ratio: 0.808, 95% CI 0.414-1.578). The 3-year survival rates were 92.3 and 91.8% in the SOX and mFOLFOX6 arms, respectively. The surgical completion rate was 98.1% overall, 100% in the SOX arm, and 96.0% in the mFOLFOX6 arm. The incidences of pathological response rates ≥grade 1b were 41.5 and 43.8% in the SOX and mFOLFOX6 arms, respectively. Both treatments were manageable and tolerable.

CONCLUSION

We demonstrated the effectiveness and safety of SOX and mFOLFOX6, both of which may be new neoadjuvant treatment candidates in previously untreated LARC cases.

TRIAL REGISTRATION

Date of enrolment of the first participant to the trial: 3rd Oct 2013; This study was registered in the UMIN clinical trials registry on 14th Aug, 2013. (Prospectively registered, UMIN-CTR number UMIN000011486). https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&recptno=R000013441&language=J.

Three dimensional cultivation increases chemo- and radioresistance of colorectal cancer cell lines

Although 2D cell cultures are commonly used to predict therapy response, it has become clear that 3D cultures may better mimic the in vivo situation and offer the possibility of tailoring translational clinical approaches. Here, we compared the response of 2D and 3D colorectal cancer (CRC) cell lines to irradiation and chemotherapy. Classic 2D cultures and 3D spheroids of CRC cell lines (CaCo2, Colo205, HCT116, SW480) were thoroughly established, then irradiated with doses of 1, 4, or 10 Gy, using a clinical-grade linear accelerator. The response was assessed by immunohistochemistry, flow cytometry, and TUNEL assays. Upon irradiation, CRC 3D spheroids were morphologically altered. After irradiation with 10 Gy, annexin V/PI staining revealed a 1.8- to 4-fold increase in the apoptosis rate in the 2D cell cultures (95% CI 3.24±0.96), and a 1.5- to 2.4-fold increase in the 3D spheroids (95% CI 1.56±0.41). Irradiation with 1 Gy caused 3- and 4-fold increases in TUNEL positive cells in the CaCo2 and HCT116 (p = 0.01) 2D cultures, respectively, compared with a 2-fold increase in the 3D spheroids. Furthermore, the 2D and 3D cultures responded differently to chemotherapy; the 3D cultures were more resistant to 5-FU and cisplatin, but not to doxorubicin and mitomycin C, than the 2D cultures. Taken together, CRC cells cultured as 3D spheroids displayed markedly higher resistance to irradiation therapy and selected chemotherapeutic drugs than 2D cultures. This in vitro difference must be considered in future approaches for determining the ideal in vitro systems that mimic human disease.

Radiation Therapy for Rectal Cancer: Executive Summary of an ASTRO Clinical Practice Guideline

PURPOSE

This guideline reviews the evidence and provides recommendations for the indications and appropriate technique and dose of neoadjuvant radiation therapy (RT) in the treatment of localized rectal cancer.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on the use of RT in preoperative management of operable rectal cancer. These questions included the indications for neoadjuvant RT, identification of appropriate neoadjuvant regimens, indications for consideration of a nonoperative or local excision approach after chemoradiation, and appropriate treatment volumes and techniques. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Neoadjuvant RT is recommended for patients with stage II-III rectal cancer, with either conventional fractionation with concurrent 5-FU or capecitabine or short-course RT. RT should be performed preoperatively rather than postoperatively. Omission of preoperative RT is conditionally recommended in selected patients with lower risk of locoregional recurrence. Addition of chemotherapy before or after chemoradiation or after short-course RT is conditionally recommended. Nonoperative management is conditionally recommended if a clinical complete response is achieved after neoadjuvant treatment in selected patients. Inclusion of the rectum and mesorectal, presacral, internal iliac, and obturator nodes in the clinical treatment volume is recommended. In addition, inclusion of external iliac nodes is conditionally recommended in patients with tumors invading an anterior organ or structure, and inclusion of inguinal and external iliac nodes is conditionally recommended in patients with tumors involving the anal canal.

CONCLUSIONS

Based on currently published data, the American Society for Radiation Oncology task force has proposed evidence-based recommendations regarding the use of RT for rectal cancer. Future studies will look to further personalize treatment recommendations to optimize treatment outcomes and quality of life.

Systemic chemotherapy and short-course radiation in metastatic rectal cancers: A feasible paradigm in unresectable and potentially resectable cancers

Background:

The optimal use and sequencing of short-course radiotherapy (SCRT) in metastatic rectal cancers (mRCs) are not well established.

Materials and Methods:

We retrospectively reviewed the records of mRC patients receiving SCRT followed by palliative chemotherapy between January 1, 2013, and December 31, 2016, in Tata Memorial Hospital. Patients were classified as having “potentially resectable” disease (local and metastatic) or “unresectable” disease at baseline based on prespecified criteria.

Results:

A total of 105 consecutive patients were available for analysis. The median age of patients was 48 years (range: 16–62 years), and 57.1% were male patients. Signet ring histology was seen in 13.3% of patients. The most common site of metastases was liver limited (29.5%), nonloco-regional nodes (12.4%), and lung limited metastases (9.5%). Chemotherapeutic regimens administered were capecitabine-oxaliplatin (70.5%), modified 5 fluorouracil (5 FU)-leucovorin-irinotecan-oxaliplatin (10.5%), and modified 5 FU-leucovorin-irinotecan (8.6%). Targeted therapy accompanying chemotherapy was administered in 27.6% of patients. About 42.1% of patients with potentially resectable disease and 11.1% with the unresectable disease at baseline underwent curative-intent resection of the primary and address of metastatic sites. With a median follow-up 18.2 months, median overall survival (OS) was 15.7 months (95% confidence interval: 10.42–20.99). Patients classified as potentially resectable had a median OS of 32.62 months while patients initially classified as unresectable had a median OS of 13.04 months (P = 0.016). The presence of signet ring morphology predicted for inferior mOS (P = 0.021).

Conclusions:

SCRT followed by systemic therapy in mRC is a feasible, efficacious paradigm for maximizing palliation, and achieving objective responses. The classification of patients based on resectability was predictive of actual resection rates as well as outcomes. Signet ring mRC show inferior outcomes in this cohort of patients.

Implementing continued radiation therapy for cancer management in low resource countries during and after the COVID-19 crisis

Introduction: Oncologists have an arduous task of weighing the urgency of treating cancer patients against risk for COVID-19 exposure, especially in low resource countries, where there is shortage of radiation equipment, personnel as well as resources to deal with the crisis. Strategic planning to control the spread of infection is critical in this susceptible patient population as well as healthcare workers involved in radiation delivery.Areas covered: We reviewed all the available literature and present feasible strategies for sustainable and continued care of cancer patients amidst this pandemic.Expert opinion: Further research is warranted to maintain and improve survival outcomes for cancer patients in spite of necessary restrictions.

Pelvic local recurrence as first relapse predicts prognosis for clinical stage II/III lower rectal cancer: A clinicopathological investigation

The present study investigated the association between the mode of tumor recurrence and prognosis in 123 patients with clinical stage II/III rectal cancer. In the past 10 years, patients received systemic chemotherapy following radical (R0, with no macroscopic residual tumor lesions) resection using total or tumor-specific mesorectal excision. Patients with rectosigmoid cancer and T4 + chemoradiation therapy were excluded from the present study. The 5-year relapse-free survival rate (5Y-RFS), 5-year overall survival rate (5Y-OS), and associations between early post-operative complications, recurrence mode and prognosis, as well as the 5Y-OS of patients with relapsed cancer, were calculated. The overall 5Y-RFS and 5Y-OS were 71.4 and 83.5%, respectively, and the overall recurrence rate was 22.8% (28/123 patients). Among relapses, remote metastases were observed in 17/123 patients (13.8%): The lung in 8 patients (6.5%), the liver in 5 patients (4.1%) and elsewhere in 4 patients (3.3%). A total of 11 patients (8.9%) had pelvic local recurrence as the first relapse, which was located anterior to the sacrum in 7 patients (5.7%), at the anastomosis site in 2 patients (1.6%), and in the inner pelvis in 2 patients (1.6%). Among relapsed patients, the 5Y-OS was 69.3% in those with distant metastases and 27.3% in those with local relapse (P=0.02; no significant differences in patient demographics). The results indicated that advanced rectal cancer and control of pelvic local recurrence are manageable by R0 resection and postoperative chemotherapy. However, for patients whose initial relapse was pelvic local recurrence, the relapsed tumor initiated a new metastatic cascade to organs, such as the lung and liver, and affected prognosis.

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.

Radiosensitivity of Cancer Stem Cells Has Potential Predictive Value for Individual Responses to Radiotherapy in Locally Advanced Rectal Cancer

Simple Summary

Radiotherapy is often used as a neo-adjuvant treatment in locally advanced rectal cancer. While treatment generally induces an improvement in the outcome, some patients show resistance to treatment for reasons that still have to be elucidated. In this work, we report an in vitro and in vivo model based on patient-derived cancer stem cells. This model is able to predict individual responses to radiotherapy. The results indicate that cells found to be radiation-sensitive in vitro generated radiation-sensitive tumor xenografts upon subcutaneous implantation. Analogously, cancer stem cells (CSCs) that did not respond to in vitro radiation treatment generated radiation-resistant tumor xenografts. Moreover, radioresistant CSCs were generally isolated via biopsies of patients with poor responses to neo-adjuvant radiotherapy. This suggests that a cell-based in vitro test may itself be sufficient to predict outcomes in donor patients.

Abstract

Neo-adjuvant radiotherapy is frequently employed in the therapeutic management of locally advanced rectal cancer (LARC). Radiotherapy can both reduce local recurrence and improve the success of surgical procedures by reducing tumor mass size. However, some patients show a poor response to treatment, which results in primary resistance or relapse after apparent curative surgery. In this work, we report in vitro and in vivo models based on patient-derived cancer stem cells (CSCs); these models are able to predict individual responses to radiotherapy in LARC. CSCs isolated from colorectal cancer biopsies were subjected to in vitro irradiation with the same clinical protocol used for LARC patients. Animal models, generated by CSC xenotransplantation, were also obtained and treated with the same radiotherapy protocol. The results indicate that CSCs isolated from rectal cancer needle biopsies possess an intrinsic grade of sensitivity to treatment, which is also maintained in the animal model. Notably, the specific CSCs’ in vitro and in vivo sensitivity values correspond to patients’ responses to radiotherapy. This evidence suggests that an in vitro radiotherapy response predictivity assay could support clinical decisions for the management of LARC patients, thus avoiding radiation toxicity to resistant patients and reducing the treatment costs.

Management of the adenocarcinoma of the upper rectum: a reappraisal

The present review attempts to assess whether upper rectal cancer (URC) should be treated either as colon cancer or as rectal one, namely to be managed with upfront surgery without neo-adjuvant treatment and partial mesorectal excision (PME), or with neo-adjuvant short course radiotherapy (SCRT) or chemoradiotherapy (CRT) as indicated, followed by surgery with total mesorectal excision. Reports from current evidence including studies, reviews and various guidelines are conflicting. Main reasons for inability to reach safe conclusions are (i) the various anatomical definitions of the rectum and its upper part, (ii) the inadequate preoperative local staging,(iii) the heterogeneity of selection criteria for the neo-adjuvant treatment,(iv) the different neo-adjuvant treatment regimens, and(v) the variety in the extent of surgical resection, among the studies. Although not adequately supported, locally advanced URC can be treated with neo-adjuvant CRT provided the lesion is within the radiation field of safety, and a PME if the lower border of the tumour is located above the anterior peritoneal reflection. There is evidence that adjuvant chemotherapy is of benefit in high-risk stage II and stage III lesions.

Effects of neoadjuvant chemotherapy with or without intensity-modulated radiotherapy for patients with rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision and adjuvant chemotherapy is the standard regimen for patients with locally advanced rectal cancer (LARC). However, whether and to which extent neoadjuvant radiotherapy could be removed from nCRT for patients with LARC is still unclear. This was a multicenter, retrospectively recruited, prospectively maintained cohort study. A propensity score matching model was employed to minimize potential confounding factors between subgroup patients treated with neoadjuvant chemotherapy (nCT) or nCRT. Overall survival (OS), disease‐free survival (DFS), local recurrence‐free survival (LRFS), and distant metastasis‐free survival (DMFS) were assessed between subgroup patients by Kaplan‐Meier analysis, log‐rank test, and Cox regression model. In total, 3233 consecutive patients, consist of 571 nCT and 2662 nCRT‐treated cases, were included. After propensity score matching (1:4), 565 nCT‐treated patients were matched to 1852 nCRT‐treated patients. Compared with nCT, nCRT treatment indeed decreased 3‐y local recurrence (10.0% vs 6.6%, P = .026), but had no impact on OS, DFS and DMFS (all P > .05) for LARC. Stratified analysis further confirmed that nCRT treatment was associated with higher 3‐y LRFS and 3‐y DFS than nCT treatment for baseline high‐risk subgroup (cT4, cN+, and cIII stage) patients (all P < .05). Conversely, for the baseline low‐risk subgroup patients (cT3, cN0, and cII stage), nCRT and nCT treatment had similar 3‐y OS, LRFS, DFS, and DMFS (all P > .05). The administration of neoadjuvant radiotherapy for LARC patients might be determined by baseline risk classification, the high‐risk individuals could be delivered while low‐risk patients might be omitted.

The optimal timing for the interval to surgery after short course preoperative radiotherapy (5 ×5 Gy) in rectal cancer - are we too eager for surgery?

BACKGROUND

The improved overall survival (OS) after short course preoperative radiotherapy (SCPRT) using 5 × 5 Gy reported in the early rectal cancer trials could not be replicated in subsequent phase III trials. This original survival advantage is attributed to poor quality of surgery and the large differential in local recurrence rates, with and without SCPRT. Immuno-modulation during and after SCPRT and its clinical implications have been poorly investigated. We propose an alternative explanation for this survival benefit in terms of immunological mechanisms induced by SCPRT and the timing of surgery, which may validate the concept of consolidation chemotherapy.

MATERIAL AND METHODS

We reviewed randomized controlled trials (RCTs) and studies of SCPRT from 1985 to 2019. We aimed to examine the precise timing of surgery in days following SCPRT and identify evidence for immune modulation, neo-antigens and memory cell induction by radiation.

RESULTS

Considerable variability is reported in randomised trials for median overall treatment time (OTT) from start of SCPRT to surgery (8-14 days). Only three early trials showed a benefit in terms of OS from SCPRT, although the level of benefit in preventing local recurrence was consistent across all trials. Different patterns of immune effects are observed within days after SCPRT depending on the OTT, but human leukocyte antigen (HLA)-1 expression was not upregulated.

CONCLUSIONS

SCPRT has a substantial immune-stimulatory potential. The importance of the timing of surgery after SCPRT may have been underestimated. An optimal interval for surgery after 5 × 5 Gy may lead to better outcomes, which is possibly exploited in total neoadjuvant therapy schedules using consolidation chemotherapy. Individual patient meta-analyses from appropriate SCPRT trials examining outcomes for each day and prospective trials are needed to clarify the validity of this hypothesis. The interaction of SCPRT with tumour adaptive immunology, in particular the kinetics and timing, should be examined further.

Prognostic Significance of Neoadjuvant Rectal Scores in Preoperative Short-Course Radiotherapy and Long-Course Concurrent Chemoradiotherapy for Patients with Locally Advanced Rectal Cancer

BACKGROUND

This study aimed to investigate the prognostic factors and the utility of the neoadjuvant rectal (NAR) score for patients who have locally advanced rectal cancer (LARC) treated with preoperative short-course radiotherapy (SRT) or long-course concurrent chemoradiotherapy (CRT).

METHODS

Of 314 consecutive stage 2 or 3 rectal cancer patients enrolled from January 2006 to December 2017, 205 underwent preoperative SRT (2500 cGy/5 fractions), and 109 underwent preoperative CRT (4200-5080 cGy/21-28 fractions) after total mesorectal excision (TME). The study calculated NAR scores using the following equation: [5 pN - 3(cT - pT) + 12]²/9.61.

RESULTS

The multivariate analysis showed that age above 65 years, pT4, pN2, NAR scores higher than 16, and distance from anal verges (< 8 cm) were significant prognostic factors for overall survival (OS), whereas, pN2, NAR scores lower than 16, and distance from anal verges (< 8 cm) were significant prognostic factors for disease-free survival (DFS) and distant metastasis (DM). The patients with an NAR score higher than 16, had a 5-year OS rate of 67.6%, a DFS rate of 56.9%, a locoregional recurrence (LRR) rate of 7.7%, and a DM rate of 35% compared with corresponding rates of 87.6%, 76.7%, 5.4%, and 7.2% for the patients with an NAR score of 16 or lower (p < 0.001 for OS, < 0.001 for DFS, 0.25 for LRR, and < 0.001 for DM).

CONCLUSIONS

For patients who undergo SRT or CRT for LARC, a higher NAR score is associated with worse OS and DFS and higher DM rates at 5 years. The NAR score could be used as a short-term surrogate end point after neoadjuvant therapy for LARC.

Dosimetric Parameters Predicting Late Small Bowel Toxicity in Patients With Rectal Cancer Receiving Neoadjuvant Chemoradiation

PURPOSE

The aim of this study was to identify dosimetric parameters that predict late small bowel (SB) toxicity after neoadjuvant long course chemoradiation (CRT) for rectal cancer.

METHODS AND MATERIALS

Four hundred eighty-six consecutive patients with locally advanced rectal cancers (clinical T3/T4 or N1/N2) who received CRT followed by surgery and had dosimetric data available for analysis were included in this study. The dose-volume relationship between small bowel irradiation and late small bowel toxicity was evaluated and a mathematical model to predict for late SB toxicity was derived.

RESULTS

Among the 486 patients with a median follow-up of 60 months from completion of radiation, 36 (7.4%) patients experienced ≥ grade 2 and 21 (4.3%) developed ≥ grade 3 late SB toxicity. A statistically significant association between the development of grade ≥3 late small bowel toxicity and the volume of small bowel irradiated was found at each dose level from 5 to 40 Gy (P < .001 for all dose volumes) in 5 Gy intervals. The average SB volume for patients who experienced grade ≥2 SB toxicity was 2149.9 cm³ and the average SB volume for patients who experienced grade ≥3 SB toxicity was 2179.9 cm³. The predicted V30 for a 5% risk for grade ≥2 SB toxicity was 101.5 cm³ and for grade ≥3 SB toxicity was 201.5 cm³. The volume of small bowel receiving at least 30 Gy (V30) was most strongly associated with grade ≥3 SB toxicity.

CONCLUSIONS

This study demonstrates the significant dose-volume relationship between volume of small bowel receiving 30 Gy (V30 Gy) and late grade ≥3 SB toxicity. When planning CRT for patients with rectal cancer, restricting V30 to <200 cm³ will be a useful guideline to minimize the 5 year grade ≥3 late SB toxicity to <5%.

A Comprehensive Review of Randomized Clinical Trials Shaping the Landscape of Rectal Cancer Therapy

Colorectal carcinoma is the second leading cause of cancer-related deaths in the United States, with rectal cancer accounting for approximately one third of newly diagnosed cases. Surgery remains the cornerstone of curative therapy, with total mesorectal excision being the standard of care. Although minimally invasive procedures might be appropriate for a subset of patients with early-stage, superficial tumors, the standard of care for medically operable patients with nonmetastatic rectal cancer includes a comprehensive multimodality approach of neoadjuvant chemoradiotherapy, surgery with total mesorectal excision, and systemic chemotherapy. However, the morbidity and mortality related to both local and distant organ relapse have remained challenging. In the present review, we have discussed the trial-level evidence that has shaped the current clinical practice patterns in the treatment of curable, nonmetastatic rectal cancer. In addition, we have discussed the anticipated results of ongoing clinical trials and outlined pragmatic opportunities for future investigation to optimize the current status quo and, hopefully, provide prospective validation of novel approaches in the treatment of rectal cancer.

Factors influencing recurrence of stage I-III rectal cancer in regional Australia

BACKGROUND

As treatments for rectal cancer improve with developments in surgical techniques, radiotherapy and chemotherapy, the nature of recurrences are evolving. We used a comprehensive database of a large Australian population with stage I-III rectal adenocarcinoma to identify timing and prognostic significance of recurrences, and factors associated with risk of developing recurrent disease.

METHODS

All patients with locoregional rectal cancer treated with curative intent in our health district from 2006 to 2017 were included. Multivariate analysis using Cox regression models were used to identify factors associated with recurrence.

RESULTS

A total of 483 patients were included. Recurrence occurred in 117 (24.2%) of 483 patients, being locoregional in 15 (3.1%) patients, distant in 85 patients (17.6%) and both locoregional and distant in 17 (3.5%) patients. Compared to those with locoregional recurrence, those with both locoregional and distant recurrence had worse cancer-specific survival. On univariate analysis, factors associated with recurrence included stage, grade, radiotherapy, chemotherapy, surgery type and distal tumour location. Factors which remained significant on multivariate analysis included higher grade and stage.

CONCLUSION

In the era of multimodality therapy for rectal cancer, recurrences are predominantly distant. Traditional predictors including higher stage, grade and distal tumour location remain independently associated with recurrence, despite current treatment paradigms.

Development of the 'PREDICT' score through a systematic review and meta-analysis of the predictive parameters for locoregional recurrence after total mesorectal excision

BACKGROUND

Despite robust management techniques, locoregional recurrence rates of rectal cancer are still significant. Although offering intensive follow-up has been shown to be beneficial in the early detection, it can be resource consuming. Having a robust knowledge of risk factors of locoregional recurrence will help in identification of patients who actually need intensive follow-up programs. This review aimed to identify the factors that can predict locoregional recurrence after Total mesorectal excision (TME).

METHODS

We systematically reviewed PubMed, Scopus and Cochrane for relevant articles with no date restrictions while language was restricted to English. We only included articles that had either provided Hazards ratio (HR)/odds ratio (OR) or provided enough data that allowed calculation of HR/OR specifically for rectal cancer. Articles were deemed eligible if they included patients undergoing (TME).

RESULTS

Seventeen studies (18,605 patients) published between 2002 and 2019 were included. A total of 699 patients developed locoregional recurrence at a median time of 25.2 months after surgery. There were eight significant predictors evaluated by more than one study; T3-T4 stage, circumferential resection margin, lymphovascular invasion, mucinous histology, N1-N2 stage, positive distal resection margin, Tumor < 5 cm from anal verge, and lack of neoadjuvant radiotherapy. A scoring system was developed based on the weight and pooled OR/HR of each predictor.

CONCLUSION

Using predictive factors identified in our review in context of scoring system may help in the early detection of locoregional recurrence after TME. This may help in tailoring the application of intensive follow-up programs.

Effect of understaging on local recurrence of rectal cancer

Background and Objectives

Magnetic resonance imaging of the pelvis has a limited accuracy to detect positive lymph nodes but does dictate neoadjuvant treatment in rectal cancer. This study aimed to investigate preoperative lymph node understaging and its effects on postoperative local recurrence rate.

Methods

Patients were selected from a retrospective cross‐sectional snapshot study. Patients with emergency surgery, cM1 disease, or unknown cN‐ or (y)pN category were excluded. Clinical and pathologic N‐categories were compared and the impact on local recurrence was determined by multivariable analysis.

Results

Out of 1548 included patients, 233 had preoperatively underestimated lymph node staging based on (y)pN category. Out of the 695 patients staged cN0, 168 (24%) had positive lymph nodes at pathology, and out of the 594 patients staged cN1, 65 (11%) were (y)pN2. Overall 3‐year local recurrence rate was 5%. Clinical N‐category was not associated with local recurrence when corrected for pT‐category, neoadjuvant therapy, and resection margin, neither in patients with (y)pN1 (hazard ratio [HR]: 1.67 (95% confidence interval [CI]: 0.68‐4.12) P = .263) nor (y)pN2‐category (HR: 1.91 95% CI: [0.75‐4.84], P = .175).

Conclusion

Preoperative understaging of nodal status in rectal cancer is not uncommon. No significant effect on local recurrence or overall survival rates were found in the present study.

Postoperative radio-chemotherapy for rectal cancer: A retrospective analysis from a tertiary referral hospital

Aim

To report results of postoperative radio-chemotherapy (RT-CHT) for rectal cancer (RC).

Background

Total mesorectal excision (TME) is an essential treatment method in rectal cancer (RC). Perioperative radiotherapy in locally advanced RC improves loco-regional free survival (LRFS). Preoperative radiotherapy is a preferred option; however, some patients are not referred for it. In case of the risk of loco-regional failure postoperative radio-chemotherapy (RT-CHT) is indicated.

Material and methods

Between 2004 and 2010, 182 patients with pathological stage II-III RC (TME performed - 41%, resection R0 - 88%, circumferential resection margin evaluated - 55.5% and was above 2 mm in 66% of them) received postoperative RT-CHT in our institution. Overall survival (OS) and LRFS were estimated with the Kaplan-Meier method. Univariate and multivariate analysis were performed to compare the impact of prognostic factors on survival.

Results

Five-year OS and LRFS rates were 63% and 85%, respectively. Loco-regional recurrence and isolated distant metastases rates were 11.5% and 19%, respectively. Multivariate analysis showed stage (III vs. II), HR: 2.3 (95% confidence interval [CI]: 1.4-3.8), p = 0.0001; extent of resection (R1-2 vs. R0), HR: 2.14 (95%CI: 1.14-3.99), p = 0.017, and age (>65 vs. ≤65 years), HR: 1.66 (95%CI: 1.06-2.61), p = 0.027 as prognostic factors for OS. Extent of resection (R1-2 vs. R0), HR: 3.65 (95%CI: 1.41-9.43), p = 0.008 had significant impact on LRFS.

Conclusion

Despite a suboptimal quality of surgery and pathological reports, the outcome in our series is close to that reported in the literature. We confirm a strong impact of the extent of resection on patient's outcome, which confirms the pivotal role of surgery in the management of RC.

Short-course versus long-course neoadjuvant chemoradiotherapy in patients with rectal cancer: preliminary results of a randomized controlled trial

Purpose

Colorectal cancer is becoming an increasing concern in the middle-aged population of Iran. This study aimed to compare the preliminary results of short-course and long-course neoadjuvant chemoradiotherapy treatment for rectal cancer patients.

Materials and Methods

In this clinical trial we recruited patients with rectal adenocarcinoma located from 5 cm to 15 cm above the anal verge. Patients in group I (short-course) received three-dimensional conformational radiotherapy with a dose of 25 Gy/5 fractions in 1 week plus concurrent XELOX regimen (capecitabine 625 mg/m² from day 1–5 twice daily and oxaliplatin 50 mg/m² on day 1 once daily). Patients in group II (long-course) received a total dose of 50–50.4 Gy/25–28 fractions for 5 to 5.5 weeks plus capecitabine 825 mg/m² twice daily. Both groups underwent consolidation chemotherapy followed by delayed surgery at least 8 weeks after radiotherapy completion. The pathological response was assessed with tumor regression grade.

Results

In this preliminary report on complications and pathological response, 66 patients were randomized into two study groups. Mean duration of radiotherapy in groups I and II was 5 ± 1 days (range, 5 to 8 days) and 38 ± 6 days (range, 30 to 58 days). The median follow-up was 18 months. Pathological complete response was achieved in 32.3% and 23.1% of patients in the short-course and long-course groups, respectively (p = 0.558). Overall, acute grade 3 or higher treatment-related toxicities occurred in 24.2% and 22.2% of patients in group I and II, respectively (p = 0.551). No acute grade 4 or 5 adverse events were observed in either group except one grade 4 hematologic toxicity that was seen in group II. Within one month of surgery, no significant difference was seen regarding grade ≥3 postoperative complications (p = 0.333).

Conclusion

For patients with rectal cancer located at least 5 cm above the anal verge, short-course radiotherapy with concurrent and consolidation chemotherapy and delayed surgery is not different in terms of acute toxicity, postoperative morbidity, complete resection, and pathological response compared to long-course chemoradiotherapy.

Management of synchronous lateral pelvic nodal metastasis in rectal cancer in the era of neoadjuvant chemoradiation: A systemic review

BACKGROUND

Lateral pelvic lymph node (LLN) metastasis (LLNM) occur in up to 28% of patients with low rectal tumours. While prophylactic lateral pelvic lymph node dissection (LLND) has been abandoned by most western institutions in the era of neoadjuvant chemoradiation therapy (CRT), the role of selective LLND in patients with enlarged LLN on pre-CRT imaging remains unclear. Some studies have shown improved survival and recurrence outcomes when LLNs show “response” to CRT. However, no management algorithm exists to differentiate treatment for “responders” vs “non-responders”.

AIM

To determine if selective LLND in patients with enlarged LLNs results in improved survival and recurrence outcomes.

METHODS

A systemic search of PubMed and Embase databases for studies reporting on patients with synchronous radiologically suspicious LLNM (s-LLNM) in rectal cancer receiving preoperative-CRT was performed.

RESULTS

Fifteen retrospective, single-centre studies were included. 793 patients with s-LLNM were evaluated: 456 underwent TME while 337 underwent TME with LLND post-CRT. In the TME group, local recurrence (LR) rates range from 12.5% to 36%. Five-year disease free survival (DFS) was 42% to 75%. In the TME with LLND group, LR rates were 0% to 6%. Five years DFS was 41.2% to 100%. Radiological response was seen in 58%. Pathologically positive LLN was found in up to 94% of non-responders vs 0% to 20% in responders. Young age, low tumour location and radiological non-response were associated with final positive LLNM and lowered DFS.

CONCLUSION

LLND is associated with local control in patients with s-LLNM. It can be performed in radiological non-responders given a large majority represent true LLNM. Its role in radiological responders should be considered in selected high risk patients.

Radiation Oncology Strategies to Flatten the Curve During the Coronavirus Disease 2019 (COVID-19) Pandemic: Experience From a Large Tertiary Cancer Center

During the coronavirus disease 2019 pandemic, minimizing exposure risk for patients with cancer and health care personnel was of utmost importance. Here, we present steps taken to date to flatten the curve at the radiation oncology division of a tertiary cancer center with the goal of mitigating risk of exposure among patients and staff, and optimizing resource utilization. Response to the coronavirus disease 2019 pandemic in this large tertiary referral center included volume reduction, personal protective equipment recommendations, flexible clinic visit interaction types dictated by need and risk reduction, and numerous social distancing strategies. We hope these outlined considerations can assist the wider radiation oncology community as we collectively face this ongoing challenge.

Rectal neuroendocrine carcinoma: case report of a rare entity and perspective review of promising agents

Neuroendocrine neoplasms (NENs) comprise a heterogeneous group of tumours, which can be classified into neuroendocrine tumours (NETs), neuroendocrine carcinomas (NECs) and mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs). To date, there is no consensus regarding the optimal therapy, which usually depends on the primary location and classification, according to morphological features of differentiation and proliferation rates. Nevertheless, multidisciplinary strategies combining medical treatments and locoregional strategies have yielded better efficacy results. Here, we report the case of a patient diagnosed with a nonfunctional rectal NECs with metastatic widespread to pelvic lymph nodes and bilateral lung metastases. The patient received three cycles of platinum-etoposide, concomitantly with palliative radiotherapy. Although CT scan after three cycles showed a significant partial response, there was an early fatal progression only 3 months after having stopped systemic therapy. As formerly described in the literature, this case highlights the aggressive behaviour of NECs, rare tumours that often present in advanced stages at diagnosis. Lately, new insights into the molecular biology of NECs have unveiled the possibility of using novel drugs, such as targeted agents or immunotherapy, in molecularly selected subgroups of patients. In this review, we discuss the current management of this rare entity and provide an overview of the most relevant molecular findings, whilst illustrating the potential value that prescreening panels can offer, searching for actionable targets (MSI/dMMR, PD-L1, BRAF^v600E) to guide therapy with promising agents that could fill a void in this disease.

PAI1 is a Marker of Bad Prognosis in Rectal Cancer but Predicts a Better Response to Treatment with PIM Inhibitor AZD1208

Colorectal cancer (CRC) is the third most common cancer worldwide. The standard treatment in locally advanced rectal cancer is preoperative radiation alone or in combination with chemotherapy, followed by adjuvant chemotherapy. Rectal cancer is highly lethal, with only 20% of patients showing a complete remission (by RECIST) after standard treatment, although they commonly show local or systemic relapse likely due to its late detection and high chemotherapy resistance, among other reasons. Here, we explored the role of PAI1 (Serpin E1) in rectal cancer through the analyses of public patient databases, our own cohort of locally advanced rectal cancer patients and a panel of CRC cell lines. We showed that PAI1 expression is upregulated in rectal tumors, which is associated with decreased overall survival and increased metastasis and invasion in advanced rectal tumors. Accordingly, PAI1 expression is correlated with the expression of (Epithelial-to-Mesenchymal Transition) EMT-associated genes and genes encoding drug targets, including the tyrosine kinases PDGFRb, PDGFRa and FYN, the serine/threonine kinase PIM1 and BRAF. In addition, we demonstrate that cells expressing PAI1 protein are more sensitive to the PIM inhibitor AZD1208, suggesting that PAI1 could be used to predict response to treatment with PIM inhibitors and to complement radiotherapy in rectal tumors.

Management of Locally Advanced Rectal Cancer During The COVID-19 Pandemic: A Necessary Paradigm Change at Memorial Sloan Kettering Cancer Center

The COVID-19 pandemic will consume significant health care resources. Given the concerns for rapidly increasing infection rates in the United States, impending staffing shortages, and the potential for resource reallocation, we rapidly reevaluated our rectal cancer practice policies during this public health emergency. Before the pandemic, we commonly used total neoadjuvant therapy with a strong preference for long-course chemoradiation. In the setting of the ongoing pandemic, we now mandate short-course radiation therapy (SCRT). Despite multiple randomized trials demonstrating no difference in locoregional recurrence, distant recurrence, or overall survival between SCRT and long-course chemoradiation, the adaptation of SCRT in the United States has been low given concerns for less tumor downstaging and increased toxicity. In the setting of the ongoing and likely prolonged COVID-19 pandemic, we feel that these concerns must be reevaluated, because SCRT presents a well-validated alternative that will allow us to meet the needs of a greater number of potentially curable patients at a time when resources are severely and acutely constrained.

Preoperative Radiotherapy Leads to Significant Differences in the Plasma Protein Profile of Rectal Cancer Patients

INTRODUCTION

Colorectal cancer (CRC) is the third most common cancer worldwide, accounting for 10% of the global cancer burden. Rectal cancer accounts for around 30% of CRC cases, and patients with resectable rectal cancer are often given preoperative radiotherapy (PRT) to reduce the rate of local recurrence. The human plasma proteome is an exceptionally complex proteome and ideal to study due to its ability to reflect the presence of diseases such as cancer and the ease of obtaining blood samples. Previous proteomic studies involving rectal cancer patients have mostly focused on the identification of proteins involved in resistance to radiotherapy.

OBJECTIVE

The aim of this study was to investigate the overall effects of PRT on plasma protein expression in rectal cancer patients, as there is a lack of such studies.

METHODS

Here, we have used mass spectrometry and subsequent statistical analyses to analyze the plasma samples of 30 rectal cancer patients according to PRT status (positive or negative) and tumor stage (II or III).

RESULTS AND CONCLUSIONS

We discovered 42 proteins whose levels differed significantly between stage II and III rectal cancer patients who did or did not receive PRT. This study shows that PRT, although localized to the pelvis, leads to measurable, tumor stage-specific changes in plasma protein expression. Future studies of plasma proteins should, when relevant, take this into account and be aware of the widespread effects that PRT has on the plasma proteome.

Adjuvant Chemotherapy Does Not Improve Recurrence-Free Survival in Patients With Stage 2 or Stage 3 Rectal Cancer After Neoadjuvant Chemoradiotherapy and Total Mesorectal Excision

BACKGROUND

Current guidelines for locally advanced stage 2/3 rectal cancer recommend neoadjuvant chemoradiotherapy followed by total mesorectal excision and adjuvant chemotherapy. The oncologic benefit of adjuvant chemotherapy has not been consistently demonstrated.

OBJECTIVE

The purpose of this study was to evaluate disease recurrence and survival in patients with rectal cancer who received adjuvant chemotherapy after chemoradiotherapy and total mesorectal excision.

DESIGN

This was a retrospective review of patients with stage 2/3 rectal cancer after chemoradiotherapy and surgery, based on receipt of adjuvant chemotherapy.

SETTINGS

The study was conducted at the Kaiser Permanente Southern California system of 14 hospitals and associated clinics.

PATIENTS

A total of 862 patients with stage 2/3 rectal cancer diagnosed and treated between January 1, 2005, and December 31, 2016, were included in this study.

INTERVENTIONS

The study involved neoadjuvant chemoradiotherapy followed by total mesorectal excision with or without adjuvant chemotherapy.

MAIN OUTCOME MEASURES

The primary end point was recurrence-free survival.

RESULTS

A total of 348 stage 2 and 514 stage 3 patients were included; 660 patients (76.6%) underwent adjuvant chemotherapy. Mean patient follow-up after surgery was 63.0 months (range, 3-160). Multivariable analysis showed that yp stage (HR for yp stage 2 = 4.74; yp stage 3 = 8.83) and en bloc resection (HR = 1.76) were the only variables that significantly predicted disease recurrence. Neither pretreatment tumor stage nor receipt of adjuvant chemotherapy was significantly associated with recurrence-free survival. Log-rank testing failed to demonstrate significant recurrence-free survival improvement after receipt of adjuvant chemotherapy in any patient subgroup.

LIMITATIONS

The study was limited by selection bias attributed to the nature of a retrospective study without patient randomization or predefined treatment protocol.

CONCLUSIONS

In stage 2/3 rectal cancer treated with chemoradiotherapy and surgery, the addition of adjuvant chemotherapy was not associated with decreased recurrence-free survival in the entire cohort or in any subgroup, whereas tumor response to chemoradiotherapy is closely associated with disease recurrence. These findings have important consequences for treatment and surveillance decisions for patients with rectal cancer. Presurgical efforts that maximize tumor downstaging, such as total neoadjuvant therapy, may produce better oncologic outcomes than traditional adjuvant chemotherapy. See Video Abstract at http://links.lww.com/DCR/B134. LA QUIMIOTERAPIA ADYUVANTE NO MEJORA LA SOBREVIDA LIBRE DE RECURRENCIA EN PACIENTES CON CÁNCER DE RECTO ESTADÍOS II O III DESPUÉS DE RADIO-QUIMIOTERAPIA NEOADYUVANTE Y ESCISIÓN TOTAL DEL MESORRECTO: Las guías actuales para el tratamiento de cáncer rectal en estadio II-III localmente avanzado, recomiendan la radio-quimioterapia neoadyuvante con escisión total del mesorrecto seguidas de quimioterapia adyuvante. El beneficio oncológico de la quimioterapia adyuvante no ha sido demostrado de manera fehaciente.Evaluar la recurrencia y sobrevida a la enfermedad en pacientes con cáncer rectal que recibieron quimioterapia adyuvante después de radio-quimioterapia y escisión total del mesorrecto.Revisión retrospectiva de pacientes con cáncer rectal en estadios II-III después de radio-quimioterapia y cirugía, basada en la recepción de quimioterapia adyuvante.Sistema Permanente de Kaiser Sur-Californiano de 14 hospitales y clínicas asociadas.862 pacientes con cáncer rectal en estadio II-III diagnosticados y tratados entre el 1 de Enero 2005 y el 31 de Diciembre 2016.Radio-quimioterapia neoadyuvante seguida de escisión total del mesorrecto +/- quimioterapia adyuvante.El objetivo primario fue la sobrevida libre de recurrencia.Fueron incluidos 348 pacientes en estadio II y 514 en estadio III. 660 pacientes (76,6%) se sometieron a quimioterapia adyuvante. El seguimiento medio de cada paciente después de la cirugía fué de 63.0 meses (rango, 3-160). El análisis multivariable mostró que la etapa yp (Cociente de riesgo para estadío yp II = 4.74 y estadío yp III = 8.83) y la resección en bloque (Cociente de riesgo = 1.76) fueron las únicas variables que predijeron significativamente la recurrencia de la enfermedad. Ni el estadío tumoral previo al tratamiento ni la recepción de quimioterapia adyuvante se asociaron significativamente con la sobrevida libre de recurrencia. Las pruebas de rango logarítmico no pudieron demostrar una mejoría significativa de la sobrevida libre de recurrencia después de recibir quimioterapia adyuvante en cualquier subgrupo de pacientes.Sesgo de selección, debido al estudio retrospectivo sin aleatorización de los pacientes o protocolo de tratamiento predefinido.En casos de cáncer de recto estadíos II-III tratados con radio-quimioterapia y cirugía, la adición de quimioterapia adyuvante no se asoció con una disminución de la sobrevida libre de recurrencia en toda la cohorte o en ningún subgrupo, mientras que la respuesta tumoral a la radio-quimioterapia está estrechamente asociada con la recurrencia de la enfermedad. Estos hallazgos tienen consecuencias importantes en la decisión del tratamiento y la vigilancia en pacientes con cáncer de recto. Los esfuerzos pre-quirúrgicos que maximizan la reducción del tamaño del tumor, como la terapia neoadyuvante total, pueden producir mejores resultados oncológicos que la quimioterapia adyuvante tradicional. Consulte Video Resumen en http://links.lww.com/DCR/B134.

Patterns of care and outcomes for adjuvant treatment of pT3N0 rectal cancer using the National Cancer Database

Background

The standard of care in locally advanced rectal cancer is preoperative chemoradiation followed by surgical resection. However, the optimal treatment paradigm is currently controversial for patients with pathological T3N0 (pT3N0) in the era of total mesorectal excision (TME). Given the paucity of data, we conducted an analysis using the National Cancer Database (NCDB) to identify patterns of care and outcomes.

Methods

We utilized the NCDB to identify 7,836 non-metastatic, pT3N0 rectal cancer patients who did not receive neoadjuvant therapy from 2004-2014. Univariate and multivariable analysis for factors affecting treatment selection were completed using logistic regression. Overall survival (OS) analyses were completed using Cox regression modeling, incorporating propensity scores with inverse probability of treatment weighting (IPTW) and conditional landmark analysis.

Results

There was a significant improvement in OS in patients receiving adjuvant chemotherapy (P<0.01) or radiotherapy (RT) with chemotherapy (P<0.01) vs. observation alone. There was no significant difference between RT vs. observation (P=0.54) and chemotherapy vs. chemotherapy with RT cohorts (P=0.15). Multivariable analysis showed age, gender, race, insurance status, income, Charlson-Deyo Comorbidity Condition (CDCC) score, facility location, grade, surgical margin, RT, and chemotherapy to be statistically significant predictors of OS. After correcting for indication and immortal time biases, chemotherapy, with or without RT, improved OS compared with observation [hazard ratio (HR) 0.48, P<0.001]. This benefit was maintained in the margin negative cohort.

Conclusions

Practice patterns vary in the management of pT3N0 rectal cancer patients. This analysis suggests that the use of adjuvant therapy, particularly adjuvant chemotherapy with or without RT, appears to improve OS.

Pathologic Complete Response Despite Nodal Yield Has Best Survival in Locally Advanced Rectal Cancer

BACKGROUND

Controversy exists regarding the ability of neoadjuvant chemoradiation (nCR) to diminish lymph node yield (LNY) and how that relationship is influenced by tumor response in patients undergoing proctectomy for locally advanced rectal cancer.

MATERIALS AND METHODS

The National Cancer Database was used to identify patients with rectal adenocarcinomas from 2004 to 2014. Patients that received nCR were compared with those that underwent surgery alone. LNY was stratified into <12 and ≥12 groups to determine their differences in stage specific overall survival.

RESULTS

Of 56,812 patients 46.5% underwent surgery alone and 53.5% were administered nCR. There were more patients with LNY<12 in the nCR group compared to surgery alone, across all stages (44.1% versus 36.5%, P < 0.001). nCR improved OS regardless of LNY (P < 0.001). Although patients with LNY≥12 had improved overall survival, patients who had a pathologic complete response (pCR) achieved the greatest survival. In patients that did not achieve a pCR, LNY≥12 was a marker of improved OS but LNY did not impact OS in patients that attained pCR (P < 0.001).

CONCLUSIONS

Although nCR diminished LNY, LNY≥12 improved OS demonstrating the importance of quality total mesorectal excision. However, LNY did not impact patients that achieved pCR. These patients, who achieved the best OS, demonstrated that tumors' biologic response to nCR had the greatest impact on patient outcomes.

Continued Improvement in Rectal Cancer Survival Outcomes Will Require True Multidisciplinary Treatment Approaches

The management of rectal cancer has undergone a significant paradigm shift, with an increased interest in the utilization of all tools in our current armamentarium of fighting it: chemotherapy, radiotherapy and surgery. Research is also underway in deciding on the best sequence for these treatments. In this review, we provide an update on some of this important work.

Dose-time fractionation schedules of preoperative radiotherapy and timing to surgery for rectal cancer

Chemoradiotherapy (CRT) is extensively used prior to surgery for rectal cancer to provide significantly better local control, but the radiotherapy (RT), as the other component of CRT, has been subject to less interest than the drug component in recent years. With considerable developments in RT, the use of advanced techniques, such as intensity-modulated radiotherapy (IMRT) in rectal cancer, is garnering more attention nowadays. The radiation dose can be better conformed to the target volumes with possibilities for synchronous integrated boost without increased complications in normal tissue. Hopefully, both local recurrence and toxicities can be further reduced. Although those seem to be of interest, many issues remain unresolved. There is no international consensus regarding the radiation schedule for preoperative RT for rectal cancer. Moreover, an enormous disparity exists regarding the RT delivery. With the advent of IMRT, variations will likely increase. Moreover, time to surgery is also quite variable, as it depends upon the indication for RT/CRT in the clinical practices. In this review, we discuss the options and problems related to both the dose-time fractionation schedule and time to surgery; furthermore, it addresses the research questions that need answering in the future.

Pathologic Response and Postoperative Complications After Short-course Radiation Therapy and Chemotherapy for Patients With Rectal Adenocarcinoma

BACKGROUND

The role of neoadjuvant short-course radiation therapy (SCRT) in treating rectal adenocarcinoma is a topic of ongoing debate. Growing interest in total neoadjuvant therapy has spurred discussion on the optimal sequence of preoperative SCRT and chemotherapy.

PATIENTS AND METHODS

All patients receiving SCRT (5 Gy × 5 fractions) were identified. Details about preoperative treatments, radiation toxicities, and postoperative complications were collected. Patients were divided into 2 groups: those who underwent surgery within 14 days of completing SCRT and those with a longer delay. Outcomes compared included extent of pathologic response, margin-negative resection rate, acute radiation toxicities, and postoperative complications.

RESULTS

Fifty-seven patients with locally advanced or metastatic rectal cancer received SCRT between 2008 and 2018. Thirty-nine of 57 patients underwent definitive pelvic surgery with total mesorectal excision. There were no significant differences in tumor downstaging, radial margin status, or percent tumor viability between patients with immediate surgery versus delayed surgery. The delay group had higher rates of nodal downstaging (64.7% vs. 18.2%; P = .003). There were no differences in total or grade 3+ gastrointestinal radiation toxicity, postoperative complications, reoperation, readmission, and mortality between the 2 groups.

CONCLUSIONS

Though not yet common in the United States, SCRT has compared favorably with long course chemoradiation in multiple trials. Moreover, it is associated with greater efficiency and less disruption to chemotherapy. Our data show similar response and toxicity outcomes between the immediate and delay groups, suggesting SCRT is well-tolerated regardless of treatment sequence. Recently completed prospective trials may reveal the optimal preoperative treatment sequence.