Neoadjuvant chemoradiotherapy with or without panitumumab in patients with wild-type KRAS, locally advanced rectal cancer (LARC): a randomized, multicenter, phase II trial SAKK 41/07

Neoadjuvant Treatment With Regorafenib and Capecitabine Combined With Radiotherapy in Locally Advanced Rectal Cancer: A Multicenter Phase Ib Trial (RECAP)-SAKK 41/16

BACKGROUND

The multi tyrosine kinase inhibitor regorafenib is active in metastatic colorectal cancer. Improvement in clinical outcome by adding regorafenib to long-course chemoradiotherapy (LcCRT) was investigated in molecularly undefined LARC.

METHODS

Patients with T3-4 and/or N+ but M0 rectal cancer were included. Neoadjuvant LcRCT consisted in capecitabine (C) 825mg/m2 d1-d38 and 28 fractions of 1.8Gy (50.4Gy). Regorafenib was added d1-14 and d22-35 in 3 dose escalation (DE) cohorts (40mg/80mg/120mg). The recommended dose (RD) was used for the expansion (EXP) cohort. Primary endpoints were dose-limiting toxicity (DLT) for DE and pathological response (near-complete regression [npCR] or complete regression [pCR]) for EXP.

RESULTS

Overall, 25 patients were included. Two DLTs occurred at the regorafenib dose level of 120 mg, thereby establishing the RD at 80mg daily. Among the 19 patients who were treated at the RD, 8 (42.1%; 1-sided 80% confidence interval [CI] (lower bound): 30.7%; 95% CI, 20.3%-66.5%) reached the primary endpoint (5 [26.3%] had npCR and 3 [15.8%] pCR). One additional patient received no surgery due to clinical complete response. All patients had R0 resections and clear circumferential margins. Postoperative complications occurred in 6 patients (35.3%). The most common grade ≥ 3 treatment-related adverse event in the EXP cohort was diarrhea (2 patients).

CONCLUSION

Adding regorafenib 80 mg to LcCRT in LARC resulted in both primary endpoints being met and yielded an expected pathological response rate. Toxicity was manageable, and postoperative complications were as expected.

Localized Rectal Cancer: Indian Consensus and Guidelines

The rising incidence of colorectal cancer (CRC) in India, particularly the prevalence of rectal cancer over colon cancer (0.7:1), has been a growing concern in recent decades; especially notable is the trend of increasing cases among young CRC patients. Given the diverse treatment approaches for rectal cancer globally and the varying economic capacities of patients in low to middle-income countries (LMICs) like India, it is essential to establish consensus guidelines that are specifically tailored to meet the needs of these patients. To achieve this, a panel comprising 30 eminent rectal cancer experts convened to conduct a comprehensive and impartial evaluation of existing practices and recent advancements in the field. Through meticulous scrutiny of published literature and a consensus-building process that involved voting on pertinent questions, the panel formulated management strategies. These recommendations are the result of a rigorous, evidence-based process and encapsulate the collective wisdom and judgment of leading authorities in the field.

Quality of Surgical Outcome Reporting in Randomised Clinical Trials of Multimodal Rectal Cancer Treatment: A Systematic Review

INTRODUCTION

Randomised controlled trials (RCTs) continue to provide the best evidence for treatment options, but the quality of reporting in RCTs and the completeness rate of reporting of surgical outcomes and complication data vary widely. The aim of this study was to measure the quality of reporting of the surgical outcome and complication data in RCTs of rectal cancer treatment and whether this quality has changed over time.

METHODS

Eligible articles with the keywords ("rectal cancer" OR "rectal carcinoma") AND ("radiation" OR "radiotherapy") that were RCTs and published in the English, German, Polish, or Italian language were identified by reviewing all abstracts published from 1982 through 2022. Two authors independently screened and analysed all studies. The quality of the surgical outcome and complication data was assessed based on fourteen criteria, and the quality of RCTs was evaluated based on a modified Jadad scale. The primary outcome was the quality of reporting in RCTs and the completeness rate of reporting of surgical results and complication data.

RESULTS

A total of 340 articles reporting multimodal therapy outcomes for 143,576 rectal cancer patients were analysed. A total of 7 articles (2%) met all 14 reporting criteria, 13 met 13 criteria, 27 met from 11 to 12 criteria, 36 met from 9 to 10 criteria, 76 met from 7 to 8 criteria, and most articles met fewer than 7 criteria (mean 5.5 criteria). Commonly underreported criteria included complication severity (15% of articles), macroscopic integrity of mesorectal excision (17% of articles), length of stay (18% of articles), number of lymph nodes (21% of articles), distance between the tumour and circumferential resection margin (CRM) (26% of articles), surgical radicality according to the site of the primary tumour (R0 vs. R1 + R2) (29% of articles), and CRM status (38% of articles).

CONCLUSION

Inconsistent surgical outcome and complication data reporting in multimodal rectal cancer treatment RCTs is standard. Standardised reporting of clinical and oncological outcomes should be established to facilitate comparing studies and results of related research topics.

Case report: The application of neoadjuvant chemoradiotherapy in anal adenocarcinoma combined with perianal Paget disease involving vulvar skin

Anal adenocarcinoma combined with perianal Paget's disease (PPD) involving the vulva is rare, and there is no established standard treatment. We present the case of a 69-year-old woman with symptoms of intermittent hematochezia and perianal discomfort for 7 months. Upon examination, we discovered a plaque-like hard mass on the right posterior wall of the anal canal, which extended to encompass the anus and dentate line. The lesion skin also extended forward from the gluteal groove, involving the bilateral labial area. Colonoscopy revealed an extensive protruding lesion on the dentate line, which was confirmed as anal adenocarcinoma (mrT4N0M0). The presence of Paget's cells in perianal and vulvar skins led to the diagnosis of PPD. The strategy of neoadjuvant chemoradiotherapy (nCRT) followed by radical surgery was then made after multi-disciplinary discuss. The scope and extent of perianal and vulvar disease were significantly diminished after nCRT. The patient underwent laparoscopic abdominoperineal resection and vulvar lesion resection, confirming the diagnosis of anal adenocarcinoma (ypT2N0). No evidence of tumor cells was found in perianal and vulvar skin, indicating a complete response. The patient is regularly monitored without recurrence or metastasis.

Total neoadjuvant therapy in rectal cancer: the evidence and expectations

Current management of locally advanced rectal cancer achieves high cure rates, distant metastatic spread being the main cause of patients' death. Total neoadjuvant therapy (TNT) employs (chemo)radiotherapy and combined chemotherapy prior to surgery to improve the treatment outcomes. TNT has been shown to reduce significantly distant metastases, increase disease-free survival by 5 - 10% in 3 years, and finally also overall survival (≈ 5% in 7 years). It proved to double the rate of pathologic complete responses, making it an attractive strategy for non-operative management to avoid permanent colostomy in patients with distal tumors. In addition, it endorses adherence to the therapy due to better tolerance and, potentially, shortens its overall duration. A number of questions related to TNT remain currently unresolved including the indications, preferred radiotherapy and chemotherapy regimens, their sequence, timing of surgery, and role of adjuvant therapy. A stratified approach may be the optimal way to go.

Radiotherapy in the preoperative neoadjuvant treatment of locally advanced rectal cancer

Radiotherapy and chemotherapy are effective treatments for patients with locally advanced rectal cancer (LARC) and can significantly improve the likelihood of R0 resection. Radiotherapy can be used as a local treatment to reduce the size of the tumor, improve the success rate of surgery and reduce the residual cancer cells after surgery. Early chemotherapy can also downgrade the tumor and eliminate micrometastases throughout the body, reducing the risk of recurrence and metastasis. The advent of neoadjuvant concurrent radiotherapy (nCRT) and total neoadjuvant treatment (TNT) has brought substantial clinical benefits to patients with LARC. Even so, given increasing demand for organ preservation and quality of life and the disease becoming increasingly younger in its incidence profile, there is a need to further explore new neoadjuvant treatment options to further improve tumor remission rates and provide other opportunities for patients to choose watch-and-wait (W&W) strategies that avoid surgery. Targeted drugs and immunologic agents (ICIs) have shown good efficacy in patients with advanced rectal cancer but have not been commonly used in neoadjuvant therapy for patients with LARC. In this paper, we review several aspects of neoadjuvant therapy, including radiation therapy and chemotherapy drugs, immune drugs and targeted drugs used in combination with neoadjuvant therapy, with the aim of providing direction and thoughtful perspectives for LARC clinical treatment and research trials.

A systematic review and network meta-analysis of randomised controlled trials comparing neoadjuvant treatment strategies for stage II and III rectal cancer

AIM

Multiple neoadjuvant therapy strategies have been used and compared for rectal cancer and there has been no true consensus as to the optimal neoadjuvant therapy regimen. The aim is to identify and compare the neoadjuvant therapies available for stage II and III rectal cancer.

DESIGN

A systematic literature review was performed, from inception to August 2022, of the following databases: MEDLINE, EMBASE, Science Citation Index Expanded, Cochrane Library. Only randomized controlled trials comparing neoadjuvant therapies for stage II and III rectal cancer were considered. Stata was used to draw network plots, and a Bayesian network meta-analysis was conducted through models utilizing the Markov Chain Monte Carlo method in WinBUGS.

RESULTS

A total of 58 articles were included based on 41 randomised controlled trials, reporting on 12,404 participants that underwent 15 neoadjuvant treatment regimens. No significant difference was identified between treatments for major or total postoperative complications, anastomotic leak rates, or sphincter-saving surgery. Straight to surgery (STS) ranked as best treatment for preoperative toxicity but ranked worst treatment for positive resection margins and complete response. STS had significantly increased positive resection margins compared to long-course chemoradiotherapy with short-wait (LCCRT-SW) or long-wait (LCCRT-LW) to surgery, or short-course radiotherapy with short-wait (SCRT-SW) or immediate surgery (SCRT-IS). LCCRT-SW or LCCRT-LW resulted in significantly increased complete response rates compared to STS. LCCRT-LW significantly improved 2-year overall survival compared to STS, SCRT-IS, SCRT-SW. Total neoadjuvant therapy regimes with short-course radiotherapy followed by consolidation chemotherapy (SCRT-CT-SW), induction chemotherapy followed by long-course chemoradiotherapy (CT-LCCRT-S), long-course chemoradiotherapy followed by consolidation chemotherapy (LCCRT-CT-S), significantly improved positive resection margins, complete response, and disease-free survival compared to STS. Chemotherapy with monoclonal antibodies followed by long-course chemoradiotherapy (CT+MAB-LCCRT+MAB-S) significantly improved complete response and positive resection margins compared to STS, and 2-year disease-free survival compared to STS, SCRT-IS, SCRT-SW, SCRT-CT-SW, LCCRT-SW, LCCRT-LW. CT+MAB-LCCRT+MAB-S ranked as best treatment for disease-free survival and overall survival.

CONCLUSIONS

Conventional neoadjuvant therapies with short-course radiation or long-course chemoradiotherapy have oncological benefits compared to no neoadjuvant therapy without increasing perioperative complication rates. Prolonged wait to surgery may improve oncological outcomes. Total neoadjuvant therapies provide additional benefits in terms of complete response, positive resection margins, and disease-free survival. Monoclonal antibody therapy may further improve oncological outcomes but currently is only applicable to a small subgroup of patients and requires further validation.

Tailored Strategy for Locally Advanced Rectal Carcinoma (GRECCAR 4): Long-term Results From a Multicenter, Randomized, Open-Label, Phase II Trial

BACKGROUND

Systematic preoperative radiochemotherapy and total mesorectal excision are the standard of care for locally advanced rectal carcinoma. Some patients can be over- or undertreated.

OBJECTIVE

This study aimed to investigate the long-term oncological, functional, and late morbidity outcomes after tailored radiochemotherapy and induction high-dose chemotherapy.

DESIGN

This is a prospective, phase II, multicenter, open-label study at 16 tertiary centers in France.

SETTINGS

Patients were operated on by surgeons from the French GRECCAR group.

PATIENTS

Two hundred six patients were randomly assigned to treatment: good responders after chemotherapy (≥75% tumor volume reduction) to immediate surgery (arm A) or standard radiochemotherapy (capecitabine 50) plus surgery (arm B) and poor responders to capecitabine 50 (arm C) or intensive radiochemotherapy (capecitabine 60; 60 Gy irradiation; arm D) before surgery.

INTERVENTIONS

Treatment was tailored according to MRI response to induction chemotherapy.

RESULTS

After induction treatment, 194 patients were classified as good (n = 30, 15%) or poor (n = 164, 85%) responders; they were included in arms A and B (16 and 14 patients) or C and D (113 and 51 patients). The primary objective was obtained: R0 resection rates (90% CI) in the 4 arms were 100% (74-100), 100% (85-100), 83% (72-91), and 88% (77-95). At 5 years, overall survival rates were 90% (47.3-98.5), 93.3% (61.3-99.0), 84.3% (71.0-91.8), and 86.1% (71.6-93.5); disease-free survival rates were 80% (40.9-94.6), 89.5% (64.1-97.3), 72.9% (58.5-82.9), and 72.8% (57.7-83.2); local recurrence rates were 0%, 0%, 2.1% (0.3-13.9), and 9.3% (3.6-23.0); and metastasis rates were 20% (5.4-59.1), 10.5% (2.7-35.9), 18% (31.8-94.6), and 18.8% (10.2-33.0). Late morbidity and quality-of-life evaluations showed no significant difference between arms.

LIMITATIONS

Limitations were due to the small number of patients randomly assigned in the good responder arms, especially arm A without radiotherapy.

CONCLUSION

Tailoring preoperative radiochemotherapy based on induction treatment response appears to be promising. Future prospective trials should confirm this strategy. See Video Abstract at http://links.lww.com/DCR/B761 .

REGISTRATION

URL: https://www.clinicaltrials.gov ; Identifier: NCT01333709.

ESTRATEGIA HECHA A MEDIDA PARA EL TRATAMIENTO DEL CARCINOMA DE RECTO LOCALMENTE AVANZADO GRECCAR RESULTADOS A LARGO PLAZO DE UN ESTUDIO ALEATRIO MULTICNTRICO Y ABIERTO DE FASE II

ANTECEDENTES:La radio-quimioterapia pré-operatoria sistemáticas y la excisión total del mesorrecto son el estándar en el tratamiento del carcinoma de recto localmente avanzado. En éste sentido, algunos pacientes podrían recibir un sobre o un infra-tratamiento.OBJETIVO:Evaluar los resultados oncológicos, funcionales y de morbilidad a largo plazo después de radio-quimioterapia personalizada y quimioterapia de inducción a dosis elevadas.DISEÑO:Estudio aleatório multicéntrico y abierto de Fase II° realizado en 16 centros terciarios en Francia.AJUSTE:Aquellos pacientes operados por cirujanos del grupo GRECCAR francés.PACIENTES:206 pacientes fueron asignados aleatoriamente al tratamiento: los buenos respondedores después de quimioterapia (reducción del volumen tumoral ≥75%) a la cirugía inmediata (brazo A) o a la radio-quimioterapia estándar (Cap 50) asociada a la cirugía (brazo B); los malos respondedores a Cap 50 (brazo C) o a la radio-quimioterapia intensiva (Cap 60 (irradiación de 60 Gy) (brazo D) previas a la cirugía.INTERVENCIONES:Tratamiento adaptado según la respuesta de la RM a la TC de inducción.RESULTADOS:Después del tratamiento de inducción, 194 pacientes fueron clasificados como buenos (n = 30, 15%) o malos (n = 164, 85%) respondedores, y se incluyeron en los brazos A y B (16 y 14 pacientes) o C y D (113 y 51 pacientes). Se alcanzó el objetivo principal: las tasas de resección R0 [intervalo de confianza del 90%] en los cuatro brazos respectivamente, fueron del 100% [74-100], 100% [85-100], 83% [72-91] y 88% [77-95]. A los 5 años, las tasas fueron: de sobrevida global 90% [47,3-98,5], 93,3% [61,3-99,0], 84,3% [71,0-91,8], 86,1% [71,6-93,5]; de sobrevida libre a la enfermedad 80% [40,9-94,6], 89,5% [64,1-97,3], 72,9% [58,5-82,9], 72,8% [57,7-83,2]; de recidiva local 0, 0, 2,1% [0,3-13,9], 9,3% [3,6-23,0]; de metástasis 20% [5,4-59,1], 10,5% [2,7-35,9], 18% [31,8-94,6], 18,8% [10,2-33,0]. La evaluación tardía de la morbilidad y la calidad de vida no mostraron diferencias significativas entre los brazos.LIMITACIONES:Debido al pequeño número de pacientes asignados al azar en los brazos de buenos respondedores, especialmente en el brazo A de aquellos sin radioterapia.CONCLUSIÓN:Parecería muy prometedor el adaptar la radio-quimioterapia pré-operatoria basada en la respuesta al tratamiento de inducción. Estudios prospectivos en el futuro podrán confirmar la presente estrategia. Consulte Video Resumen en http://links.lww.com/DCR/B761 . (Traducción-Dr. Xavier Delgadillo )IDENTIFICADOR DE CLINICALTRIALS.GOV:NCT01333709. Groupe de REcherche Chirurgicale sur le CAncer du Rectum.

Biologics in rectal cancer

INTRODUCTION

Despite the use of multimodality therapy, locally advanced rectal cancer (LARC) still presents high rates of disease recurrence. Fluoropyrimidine-based chemotherapy concurrently with radiation therapy (RT) remains the cornerstone of neoadjuvant therapy of LARC, and novel therapies are urgently needed in order to improve the clinical outcomes.

AREAS COVERED

We aim to summarize data from completed and ongoing clinical trials addressing the role of biological therapies, including monoclonal antibodies, immune checkpoint inhibitors (ICIs), antibody-drug conjugates, bispecific antibodies, and gene therapies in the systemic therapy of rectal cancer.

EXPERT OPINION

Deeper understanding of the molecular biology of colorectal cancer (CRC) has allowed meaningful advances in the systemic therapy of metastatic disease in the past few years. The larger applicability of biological therapy in CRC, including genome-guided targeted therapy, antiangiogenics, and immunotherapy, gives us optimism for the personalized management of rectal cancer. Microsatellite instability (MSI) tumors have demonstrated high sensitivity to ICIs, and preliminary findings in the neoadjuvant setting of rectal cancer are promising. To date, antiangiogenic and anti-EGFR therapies in LARC have not demonstrated the same benefit seen in metastatic disease. The outstanding results accomplished by biomarker-guided therapy in metastatic CRC will guide future developments of biological therapy in LARC.

Phase I Study of Lenvatinib and Capecitabine with External Radiation Therapy in Locally Advanced Rectal Adenocarcinoma

Background

Neoadjuvant chemoradiation with fluoropyrimidine followed by surgery and adjuvant chemotherapy has been the standard treatment of locally advanced stages II and III rectal cancer for many years. There is a high risk for disease recurrence; therefore, optimizing chemoradiation strategies remains an unmet need. Based on a few studies, there is evidence of the synergistic effect of VEGF/PDGFR blockade with radiation.

Methods

In this phase I, dose-escalation and dose-expansion study, we studied 3 different dose levels of lenvatinib in combination with capecitabine-based chemoradiation for locally advanced rectal cancer.

Results

A total of 20 patients were enrolled, and 19 were eligible for assessment of efficacy. The combination was well tolerated, with an MTD of 24 mg lenvatinib. The downstaging rate for the cohort and the pCR was 84.2% and 37.8%, respectively. Blood-based protein biomarkers TSP-2, VEGF-R3, and VEGF correlated with NAR score and were also differentially expressed between response categories. The NAR, or neoadjuvant rectal score, encompasses cT clinical tumor stage, pT pathological tumor stage, and pN pathological nodal stage and provides a continuous variable for evaluating clinical trial outcomes.

Conclusion

The combination of lenvatinib with capecitabine and radiation in locally advanced rectal cancer was found to be safe and tolerable, and potential blood-based biomarkers were identified.

Clinical Trial Registration

NCT02935309

A Patient-Derived Organoid-Based Radiosensitivity Model for the Prediction of Radiation Responses in Patients with Rectal Cancer

Simple Summary

Predicting the tumor regression grade of locally advanced rectal cancer after neoadjuvant chemoradiation is important for customized treatment strategies; however, there are no reliable prediction tools. A novel preclinical model based on patient-derived tumor organoids has shown promising features of the recapitulation of real tumors and their treatment response. We conducted a small co-clinical trial to determine the correlation between the irradiation response of individual patient-derived rectal cancer organoids and the results of actual radiotherapy. Among the quantitative experimental data, the survival fraction was best matched and correlated with the patients’ real treatment outcome. In the machine learning-based prediction model for radiotherapy results using the survival fraction data, the prediction accuracy was excellent at more than 89%. Enhanced machine learning with the accumulation of further new experimental data would help in creating a more reliable prediction model, and this new preclinical model can lead to more advanced precision medicine.

Abstract

Patient-derived tumor organoids closely resemble original patient tumors. We conducted this co-clinical trial with treatment-naive rectal cancer patients and matched patient-derived tumor organoids to determine whether a correlation exists between experimental results obtained after irradiation in patients and organoids. Between November 2017 and March 2020, we prospectively enrolled 33 patients who were diagnosed with mid-to-lower rectal adenocarcinoma based on endoscopic biopsy findings. We constructed a prediction model through a machine learning algorithm using clinical and experimental radioresponse data. Our data confirmed that patient-derived tumor organoids closely recapitulated original tumors, both pathophysiologically and genetically. Radiation responses in patients were positively correlated with those in patient-derived tumor organoids. Our machine learning-based prediction model showed excellent performance. In the prediction model for good responders trained using the random forest algorithm, the area under the curve, accuracy, and kappa value were 0.918, 81.5%, and 0.51, respectively. In the prediction model for poor responders, the area under the curve, accuracy, and kappa value were 0.971, 92.1%, and 0.75, respectively. Our patient-derived tumor organoid-based radiosensitivity model could lead to more advanced precision medicine for treating patients with rectal cancer.

Effect of mistletoe extract on tumor response in neoadjuvant chemoradiotherapy for rectal cancer: a cohort study

Background

Mistletoe extract, used as a complementary chemotherapeutic agent for cancer patients, has anticancer effects against various malignancies. The aim of the present study was to evaluate the effect of mistletoe extract (Abnoba Viscum Q®) on tumor responses to neoadjuvant chemoradiotherapy (NCRT) for locally advanced rectal cancer.

Methods

This study included patients with rectal cancer who underwent NCRT between January 2018 and July 2020. In the mistletoe group (MG), the patients were administered Abnoba Viscum Q® subcutaneously during chemoradiotherapy—maintained just before surgery. Patient demographics, clinical outcomes, histopathological outcomes, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) assay results were compared between the MG and non-mistletoe group (NMG). Two rectal cancer cell lines (SNU-503 and SNU-503R80Gy) were treated with Abnoba Viscum Q® to assess its mechanistic effects in vivo.

Results

Overall, the study included 52 patients (MG: n = 15; NMG: n = 37). Baseline demographics between the two groups were similar, except carbohydrate antigen 19-9 levels and tumor location from the anal verge. There was no difference in the clinical stage between the two groups. A better tumor response in the MG, relative to the NMG, was observed with respect to tumor regression grade (TRG), T stage, and overall tumor–node–metastasis stage. Tumor response was significantly better in the MG than in the NMG in terms of pathologic complete response rate (53.3% vs. 21.6%, P = 0.044), good TRG response (66.7% vs. 32.4%, P = 0.024), T downstaging (86.7% vs. 43.2%, P = 0.004), and overall downstaging (86.7% vs. 56.8%, P = 0.040). The toxicities during NCRT were minimal in both groups. More apoptotic cells were noted in MG samples than in the NMG samples on TUNEL staining. Cleaved caspase-3 level following treatment with Abnoba Viscum Q® was higher in SNU-503R80Gy cells than in SNU-503 cells.

Conclusion

Patients treated with chemoradiation combined with mistletoe extract showed better outcomes than patients not treated with mistletoe extract in terms of tumor responses. This diversity in treatment may improve the efficacy of NCRT, leading to better oncologic outcomes. Prospective and randomized studies with long-term follow-up are warranted to confirm and extend these results.

Complete pathological response in rectal cancer utilising novel treatment strategies for neo-adjuvant therapy: A systematic review

BACKGROUND

Locally advanced rectal cancer is routinely treated with neo-adjuvant long course chemoradiotherapy or short course radiotherapy, followed by total mesorectal excision. Not all patients respond to this treatment and there has been an emergence of novel treatment strategies designed to improve outcomes for these patients. This systematic review aims to assess the current novel neo-adjuvant treatment strategies being utilised in the treatment of patients with rectal cancer and how these impact pathological complete response (pCR) rates.

METHODS

A systematic review of the literature was performed to evaluate pathological response in patients with rectal cancer receiving novel neo-adjuvant therapy. EMBASE and Medline electronic databases were searched for relevant articles. Articles published between January 2008 and February 2019 were retrieved. Included studies underwent critical appraisal and complete pathological response rates were recorded.

RESULTS

Of the initial 1074 articles identified, 217 articles fulfilled the inclusion criteria, of these 60 articles (4359 patients) were included. Neo-adjuvant therapy delivered included novel long course chemoradiation therapy, neoadjuvant chemotherapy alone, addition of a biological agent, total neo-adjuvant therapy, novel short course radiation therapy and studies utilising biomarkers to select patients for therapy. Complete pathological response rates ranged from 0 to 60%.

CONCLUSION

A validated novel neo-adjuvant therapy that significantly increases pCR rates in patients with rectal cancer has not been identified.

Still proliferating CD44+/Ki67+ tumor cells after neoadjuvant radiochemotherapy identify rectal cancer patients with poor survival

INTRODUCTION

Distant recurrence, especially liver metastases, occurs in one-third of rectal cancer patients initially treated with curative therapy and is still an unsolved problem. The identification of patients at risk is crucial for enabling individualized treatment.

MATERIAL AND METHODS

All patients undergoing curative resection for histologically confirmed rectal cancer after neoadjuvant radiochemotherapy between January 2001 and December 2015 were included. Sections were stained for Ki67, CD44, apoptosis and CD133. Patients were categorized based on whether they were found to have (CD44⁺/Ki67⁺) or not have (CD44⁺/Ki67⁺) still proliferating tumor cells.

RESULTS

218 patients who underwent R0 resection for stage I-III rectal cancer were selected. In 37 (17%) of these patients, CD44⁺/Ki67⁺ tumor cells were found. In multivariable Cox regression analysis, patients with CD44⁺/Ki67⁺ cells had significantly impaired overall (hazard ratio (HR): 3.84, 95% CI: 1.77-8.31, p = 0.001) and relative survival (HR 3.44, 95% CI: 1.46-8.09). The previous results were confirmed after propensity-score matching. In mediation-analysis, the presence of CD44⁺/Ki67⁺ cells was associated with a substantial direct effect on overall (HR 1.92, 95% CI: 1.09-9.28) and relative survival (HR 1.63, 95% CI: 1.31-6.38).

CONCLUSIONS

The presence of still proliferating CD44⁺/Ki67⁺ tumor cells after neoadjuvant radiochemotherapy was associated with impaired oncological long-term outcomes. Characterization of these cells should be performed.

Adding Adjuvants to Fluoropyrimidine-based Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: An Option Worthy of Serious Consideration

The application of fluoropyrimidine-based neoadjuvant chemoradiotherapy (Fu-nCRT) of locally advanced rectal cancer (LARC) has become a common therapeutic regimen. In order to improve the efficacy and enable more patients to benefit from this treatment, an accumulation of studies have been carried out on the auxiliary use of other drugs with Fu-nCRT. However, due to specific challenges and the potential opportunities that coexist in this field, a more reasonable approach to the mode of treatment remains to be explored. In this review, we have summarized the results of the studies on the combination of Fu-nCRT with cytotoxic drugs, anti-tumor angiogenesis, and anti-EGFR agents, as well as the status of the application of immune checkpoint inhibitors in the neoadjuvant therapy of LARC patients.

A prospective, single-arm, multicenter trial of neoadjuvant chemotherapy with mFOLFOX6 plus panitumumab without radiotherapy for locally advanced rectal cancer

PURPOSE

The present study evaluated the safety and efficacy of neoadjuvant chemotherapy with modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus panitumumab in clinical stage III rectal cancer with KRAS wild-type.

METHODS

We conducted a prospective multicenter phase II trial. KRAS wild-type clinical stage III rectal cancer patients were enrolled. Patients received 6 cycles of mFOLFOX6 with 6 mg/kg panitumumab as neoadjuvant chemotherapy. The primary outcome was the response rate (RR) defined by RECIST. Lateral lymph node dissection (LLDN) was performed when patients had a locally advanced tumor < 9 cm from the anal margin.

RESULTS

A total of 50 patients were enrolled. Twelve (24.0%) experienced grade 3-4 adverse events during neoadjuvant chemotherapy. The RR was 88.0% (complete response 2.0%, partial response 86.0%), which met the primary outcome. All patients underwent laparoscopic surgery and achieved R0 resection. Seven patients underwent resection of other adjacent organs, and 43 underwent LLND. Twelve patients (24.0%) experienced grade 3-4 postoperative complications, and 4 (8.0%) had pathological complete response (pCR). Thirteen patients (26.0%) had lymph node metastasis. Forty-five patients (90.0%) received postoperative adjuvant chemotherapy. The 3-year relapse-free survival (RFS) and overall survival (OS) rates were 79.0% and 93.7%, respectively.

CONCLUSIONS

Neoadjuvant chemotherapy of mFOLFOX6 plus panitumumab without radiotherapy resulted in a low pCR rate but a high PR rate, low local recurrence rate, and good long-term outcome, suggesting that this treatment strategy may be a viable option for patients unable or unwilling to receive radiotherapy. The trial was registered with the UMIN Clinical Trials Registry, number 000006039.

Recent advances in (chemo-)radiation therapy for rectal cancer: a comprehensive review

The role of radiation therapy in the treatment of (colo)-rectal cancer has changed dramatically over the past decades. Introduced with the aim of reducing the high rates of local recurrences after conventional surgery, major developments in imaging, surgical technique, systemic therapy and radiation delivery have now created a much more complex environment leading to a more personalized approach. Functional aspects including reduction of acute or late treatment-related side effects, sphincter or even organ-preservation and the unsolved problem of still high distant failure rates have become more important while local recurrence rates can be kept low in the vast majority of patients. This review summarizes the actual role of radiation therapy in different subgroups of patients with rectal cancer, including the current standard approach in different subgroups as well as recent developments focusing on neoadjuvant treatment intensification and/or non-operative treatment approaches aiming at organ-preservation.

The Addition of EGFR Inhibitors in Neoadjuvant Therapy for KRAS-Wild Type Locally Advanced Rectal Cancer Patients: A Systematic Review and Meta-Analysis

Background

Patients with locally advanced rectal cancer (LARC) are at higher risk of local and distant recurrence and are thus more vulnerable to metastatic diseases. Neoadjuvant chemoradiotherapy (nCRT) and subsequent curative resection with total mesorectal excision (TME) followed by adjuvant chemotherapy have been recommended by the National Comprehensive Cancer Network (NCCN) guidelines as standard of care for LARC patients. However, the efficacy of the addition of epidermal growth factor receptor (EGFR) inhibitors in kirsten rat sarcoma viral oncogene (KRAS)-wild type LARC patients remains uncertain.

Materials

PubMed, Embase, and Web of Science were searched to retrieve records on the application of EGFR inhibitors in a neoadjuvant setting for LARC patients. pCR was used as surrogate endpoint to perform data synthesis in a single-arm setting.

Results

Ten cohorts covering 540 subjects were eligible in this systematic review. The pooled pCR rate for EGFR inhibitors was 15% (95% confidence interval (95% CI), 11-20%; I² = 55.2%); the pooled estimates of Grade 3/4 diarrhea, Grade 3/4 hand-foot syndrome, Grade 3/4 acneiform rash were 17% (95% CI, 4-34%; I² = 93.3%), 2% (95% CI, 0-5%; I² = 13.7%), and 15% (95% CI, 9-22%; I² = 65.4%), respectively.

Conclusion

The addition of EGFR inhibitors in the nCRT for KRAS-wild type LARC patients provides comparable efficacy and acceptable safety. However, the results should be interpreted cautiously due to the small amount of relevant data and need further confirmation by more future studies.

Targeting hallmarks of cancer to enhance radiosensitivity in gastrointestinal cancers

Radiotherapy is used in the treatment of approximately 50% of all malignancies including gastrointestinal cancers. Radiation can be given prior to surgery (neoadjuvant radiotherapy) to shrink the tumour or after surgery to kill any remaining cancer cells. Radiotherapy aims to maximize damage to cancer cells, while minimizing damage to healthy cells. However, only 10-30% of patients with rectal cancer or oesophageal cancer have a pathological complete response to neoadjuvant chemoradiation therapy, with the rest suffering the negative consequences of toxicities and delays to surgery with no clinical benefit. Furthermore, in pancreatic cancer, neoadjuvant chemoradiation therapy results in a pathological complete response in only 4% of patients and a partial pathological response in only 31%. Resistance to radiation therapy is polymodal and associated with a number of biological alterations both within the tumour itself and in the surrounding microenvironment including the following: altered cell cycle; repopulation by cancer stem cells; hypoxia; altered management of oxidative stress; evasion of apoptosis; altered DNA damage response and enhanced DNA repair; inflammation; and altered mitochondrial function and cellular energetics. Radiosensitizers are needed to improve treatment response to radiation, which will directly influence patient outcomes in gastrointestinal cancers. This article reviews the literature to identify strategies - including DNA-targeting agents, antimetabolic agents, antiangiogenics and novel immunotherapies - being used to enhance radiosensitivity in gastrointestinal cancers according to the hallmarks of cancer. Evidence from radiosensitizers from in vitro and in vivo models is documented and the action of radiosensitizers through clinical trial data is assessed.

Emerging trends in the treatment of rectal cancer

The conventional treatment for cT3-T4 or node-positive clinically resectable rectal cancer is long course preoperative chemoradiation followed by surgery and postoperative adjuvant chemotherapy. Disadvantages of this approach include possible overtreatment of patients, 6 weeks of daily radiation treatment, and undetected metastatic disease. There are a number of emerging trends which are changing this approach to treatment. Selected topics included in this manuscript include the selective use of pelvic radiation, the role of radiation for a positive radial margin, the interval between radiation and surgery, non-operative management, new chemoradiation regimens, short vs. long course radiation, and the role of postoperative adjuvant chemotherapy.

Efficacy and safety of consolidation chemotherapy during the resting period in patients with local advanced rectal cancer

It remains controversial as to whether a long interval between neoadjuvant chemoradiotherapy (NCRT) and surgery may provide clinical benefits for patients with local advanced rectal cancer (LARC). The addition of consolidation chemotherapy during the resting period was recently considered as a treatment option. The present study aimed to verify the efficacy and safety of consolidation chemotherapy during the resting period in patients with LARC. A total of 156 patients with local advanced stage T3-4N0-2 rectal cancer were enrolled between January 2010 and July 2016. Patients were divided into two groups, those who received consolidation chemotherapy prior to surgery (n=76) and the control group who did not (n=80). Multivariate logistic regression and the Kaplan-Meier method were used to explore the predictors of pathological complete response (pCR) and survival. The demographic and tumor characteristics were comparable between the two groups. The consolidation group yielded significantly higher pCR and near pCR rates compared with the control group (P=0.015). Patients in the consolidation group who also underwent standard adjuvant chemotherapy displayed improved 3-year disease-free survival (DFS) compared with the control group (P=0.036). Notably, the addition of consolidation chemotherapy between NCRT and surgery did not significantly increase the incidence of surgical complications and grade 3 or 4 toxicities when compared with the control group. Consolidation chemotherapy was associated with increased pCR/near pCR rates and improved 3-year DFS, and displayed a manageable safety profile. The present study provided primary evidence for the efficacy and safety of consolidation chemotherapy in LARC. Further prospective studies are warranted in the future to verify these results.

Non-operative management of rectal cancer: understanding tumor biology

The management of locally-advanced rectal cancer involves a combination of chemotherapy, chemoradiation, and surgical resection to provide excellent local tumor control and overall survival. However, aspects of this multimodality approach are associated with significant morbidity and long-term sequelae. In addition, there is growing evidence that patients with a clinical complete response to chemotherapy and chemoradiation treatments may be safely offered initial non-operative management in a rigorous surveillance program. Weighed against the morbidity and significant sequelae of rectal resection, recognizing how to best optimize non-operative strategies without compromising oncologic outcomes is critical to our understanding and treatment of this disease.

Combination of novel systemic agents and radiotherapy for solid tumors - part I: An AIRO (Italian association of radiotherapy and clinical oncology) overview focused on treatment efficacy

Over the past century, technologic advances have promoted the evolution of radiation therapy into a precise treatment modality allowing for the maximal administration of dose to tumors while sparing normal tissues. In parallel with this technological maturation, the rapid expansion in understanding the basic biology and heterogeneity of cancer has led to the development of several compounds that target specific pathways. Many of them are in advanced steps of clinical development for combination treatments with radiotherapy, and can be incorporated into radiation oncology practice for a personalized approach to maximize the therapeutic gain. This review describes the rationale for combining novel agents with radiation, and provides an overview of the current landscape focused on treatment efficacy.

Combination of novel systemic agents and radiotherapy for solid tumors - Part II: An AIRO (Italian association of radiotherapy and clinical oncology) overview focused on treatment toxicity

Clinical development and use of novel systemic agents in combination with radiotherapy (RT) is at nowadays most advanced in the field of treatment of solid tumors. Although for many of these substances preclinical studies provide sufficient evidences on their principal capability to enhance radiation effects, the majority of them have not been investigated in even phase I clinical trials for safety in the context of RT. In clinical practice, unexpected acute and late side effects may emerge especially in combination with RT. As a matter of fact, despite combined modality treatment holds potential for enhancing the therapeutic ratio, some concerns are raised from the lack of high-quality clinical data to guide the care of patients who are treated with novel compounds in conjunction with RT. The aim of this review is to provide, from a radio-oncological point of view, an overview of the most advanced combined treatment concepts for solid tumors focusing on treatment toxicity.

Systematic review of treatment intensification using novel agents for chemoradiotherapy in rectal cancer

BACKGROUND

With the well established shift to neoadjuvant treatment for locally advanced rectal cancer, there is increasing focus on the use of radiosensitizers to improve the efficacy and tolerability of radiotherapy. There currently exist few randomized data exploring novel radiosensitizers to improve response and it is unclear what the clinical endpoints of such trials should be.

METHODS

A qualitative systematic review was performed according to the PRISMA guidelines using preset search criteria across the PubMed, Cochrane and Scopus databases from 1990 to 2017. Additional results were generated from the reference lists of included papers.

RESULTS

A total of 123 papers were identified, of which 37 were included; a further 60 articles were obtained from additional referencing to give a total of 97 articles. Neoadjuvant radiosensitization for locally advanced rectal cancer using fluoropyrimidine-based chemotherapy remains the standard of treatment. The oral derivative capecitabine has practical advantages over 5-fluorouracil, with equal efficacy, but the addition of a second chemotherapeutic agent has yet to show a consistent significant efficacy benefit in randomized clinical assessment. Preclinical and early-phase trials are progressing with promising novel agents, such as small molecular inhibitors and nanoparticles.

CONCLUSION

Despite extensive research and promising preclinical studies, a definite further agent in addition to fluoropyrimidines that consistently improves response rate has yet to be found.

Skin toxicity with anti-EGFR monoclonal antibody in cancer patients: a meta-analysis of 65 randomized controlled trials

We performed a meta-analysis to fully investigate the skin toxicities of anti-EGFR monoclonal antibody (EGFR-MoAbs) in cancer patients. The relevant studies of the randomized controlled trials (RCTs) in cancer patients treated with EGFR-MoAbs were retrieved and the systematic evaluation was conducted. EMBASE, MEDLINE, and PubMed were searched for articles published till November 2017. The relevant RCTs in cancer patients treated with EGFR-MoAbs were retrieved and the systematic evaluation was conducted. 65 RCTs and 25994 patients were included. The current meta-analysis suggests that the use of EGFR-MoAbs significantly increases the risk of developing all-grade and high-grade skin toxicity, such as rash, hand-foot syndrome, dry skin and oral mucositis. Rash was the most common skin toxicity. Patients receiving nimotuzumab were associated with the least risk of skin toxicity. The risk of high-grade skin toxicity tended to be higher in the study in which the EGFR-MoAbs treatment duration was longer. The available data suggested that the use of EGFR-MoAbs significantly increases the risk of developing skin toxicity. Physicians should be aware of skin toxicity and should monitor cancer patients when receiving EGFR-MoAbs.

A review of preoperative chemoradiotherapy for lower rectal cancer

In Western countries, rectal cancer has been treated by chemoradiotherapy (CRT) for several decades now, and good local control has been reported. However, Japanese guidelines did not strongly recommend CRT, because CRT is only useful for achieving local control and imbues no survival benefit. For this reason, CRT was rarely used to treat rectal cancer in Japan. However, in the 2000s, several studies involving CRT began to be reported from Western countries, such as “correlation between pathological complete response and survival,” “induction chemotherapy followed by CRT,” and “watch-and-wait policies.” These studies were directly correlated with survival of and benefits to the patients. Given these findings, Japanese institutions have recently begun to introduce CRT for rectal cancer. Therefore, in the present study, we reviewed several topics regarding CRT for rectal cancer.

Phase II Study of Preoperative Treatment with External Radiotherapy Plus Panitumumab in Low-Risk, Locally Advanced Rectal Cancer (RaP Study/STAR-03)

BACKGROUND

Treatment with fluoropyrimidines and concomitant long-course external radiotherapy (RTE) is the standard of care in locally advanced rectal cancer (LARC) preoperative chemoradiation. A randomized phase II study (RaP/STAR-03) was conducted that aimed to evaluate the activity and safety of the monoclonal antibody anti-epidermal growth factor receptor panitumumab as a single agent in combination with radiotherapy in low-risk LARC preoperative treatment.

MATERIALS AND METHODS

Patients had adenocarcinoma of the mid-low rectum, cT3N- or cT2-T3N+, KRAS wild-type status, and negative circumferential radial margin. Panitumumab was administered concomitant to RTE. Rectal surgery was performed 6-8 weeks after the end of preoperative treatment. The adjuvant chemotherapy regimen was FOLFOX. The primary endpoint was the pathologic complete response (pCR) rate. The sample size was calculated using Simon's two-stage design. A pCR of 16% was considered to qualify the experimental treatment for further testing.

RESULTS

Ninety-eight patients were enrolled in 13 Italian centers from October 2012 to October 2015. Three panitumumab infusions were administered in 92 (93.4%) patients. The RTE compliance was median dose 50.4 Gy; ≥28 fractions in 82 (83.7%) patients. Surgical treatment was performed in 92 (93.9%) patients, and no severe intraoperative complications were observed. A pCR was observed in 10 (10.9%) patients (95% confidence interval, 4.72%-17.07%). Pathological downstaging occurred in 45 (45.9%) patients. Grade 3 toxicities were observed in 22 (22.3%) patients, and the common adverse events were skin rash in 16 (16.3%) patients. No grade 4 toxicities were reported.

CONCLUSION

The pCR rate (our primary endpoint), at only 10.9%, did not reach the specified level considered suitable for further testing. However, the analysis showed a good toxicity profile and compliance to concomitant administration of panitumumab and RTE in preoperative treatment of LARC. The pCR evaluation in all wild-type RAS is ongoing.

IMPLICATIONS FOR PRACTICE

The aim of the RaP/STAR-03 study was to evaluate the activity and safety of monoclonal antibody anti-epidermal growth factor receptor (EGFR) panitumumab as a single agent without chemotherapy in low-risk, locally advanced rectal cancer (LARC) preoperative treatment. Nevertheless, the use of panitumumab in combination with radiotherapy in preoperative treatment in patients with KRAS wild type and low-risk LARC did not reach the pathologic complete response primary endpoint. This study showed a good toxicity profile and compliance to combination treatment. Further analysis of NRAS and BRAF on tissue and circulating levels of the EGFR ligands and vascular factors (soluble vascular endothelial growth factor, E-selectin) may provide insight on the potential molecular pathways involved in the anti-EGFR response.

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

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

Neoadjuvant radiotherapy combined with capecitabine and sorafenib in patients with advanced KRAS-mutated rectal cancer: A phase I/II trial (SAKK 41/08)

BACKGROUND

KRAS mutation occurs in ∼40% of locally advanced rectal cancers (LARCs). The multitarget tyrosine kinase inhibitor sorafenib has radiosensitising effects and might improve outcomes for standard preoperative chemoradiotherapy in patients with KRAS-mutated LARC.

METHODS

Adult patients with KRAS-mutated T3/4 and/or N1/2M0 LARC were included in this phase I/II study. The phase I dose-escalation study of capecitabine plus sorafenib and radiotherapy was followed by a phase II study assessing efficacy and safety. Primary end-points were to: establish the maximum tolerated dose of the regimen in phase I; determine the pathologic complete response (pCR) rate in phase II defined as Dworak regression grade 3 and 4.

RESULTS

Fifty-four patients were treated at 18 centres in Switzerland and Hungary; 40 patients were included in the single-arm phase II study. Recommended doses from phase I comprised radiotherapy (45 Gy in 25 fractions over 5 weeks) with capecitabine 825 mg/m² twice daily × 33 plus sorafenib 400 mg/d. Median daily dose intensity in phase II was radiotherapy 100%, capecitabine 98.6%, and sorafenib 100%. The pCR rate (Dworak 3/4) was 60% (95% CI, 43.3-75.1%) by central independent pathologic review. Sphincter preservation was achieved in 89.5%, R0 resection in 94.7%, and downstaging in 81.6%. The most common grade 3 toxicities during phase II included diarrhoea (15.0%), skin toxicity outside radiotherapy field (12.5%), pain (7.5%), skin toxicity in radiotherapy field, proctitis, fatigue and cardiac ischaemia (each 5%).

CONCLUSIONS

Combining sorafenib and standard chemoradiotherapy with capecitabine is highly active in patients with KRAS-mutated LARC with acceptable toxicity and deserves further investigation. www.clinicaltrials.gov: NCT00869570.

Risk of fatigue in cancer patients receiving anti-EGFR monoclonal antibodies: results from a systematic review and meta-analysis of randomized controlled trial

BACKGROUND

To evaluate the association between fatigue and anti-epidermal growth factor receptor monoclonal antibodies (anti-EGFR MAbs), we conducted the first meta-analysis to access the incidence and risk of fatigue associated with anti-EGFR MAbs.

METHODS

Electronic databases were searched for randomized controlled trials (RCTs) published up to February 2017. Eligible studies were selected according to PRISMA statement. Incidence rates, risk ratio (RRs), and 95% confidence intervals (CIs) were calculated using fixed-effects or random-effects models. Outcomes of quality were summarized in accordance with the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology.

RESULTS

Thirty-five RCTs (including 15,622 patients) were included; median follow-up ranged from 8.1 to 71.4 months, and the fatigue events were recorded and graded according to the Common Toxicity Criteria for Adverse Events version 2.0 or 3.0 in most of the included trials. For patients receiving anti-EGFR MAbs, the overall incidence of all-grade and high-grade fatigue was 54.1% and 10.5%, respectively. Compared with control, anti-EGFR MAbs significantly increased the risk of all-grade fatigue (RR 1.10, 95% CI, 1.05-1.14, moderate-quality evidence) and high-grade fatigue (RR 1.31, 95% CI, 1.19-1.45, moderate-quality evidence). No significant differences among subgroup analyses (anti-EGFR MAbs, tumor type, and median follow-up) on high-grade fatigue were observed. No evidence of publication bias was observed.

CONCLUSION

The present study suggested that anti-EGFR MAbs may increase the risk of fatigue in cancer patients.

Neoadjuvant Treatment Strategies: Advanced Radiation Alternatives

Long-course chemoradiation therapy (CRT) has been the standard approach for locally advanced rectal tumors. Neoadjuvant CRT is associated to improved local disease control, with less toxicity when compared with adjuvant CRT, as well as the chance for pathologic complete response. The CRT regimens have improved over the past years. This article will examine selected controversies, including novel chemoradiation regimens, duration of radiation (short vs. long course), and radiation techniques such as intensity-modulated radiation therapy (IMRT).

Phase 2 Neoadjuvant Treatment Intensification Trials in Rectal Cancer: A Systematic Review

PURPOSE

Multiple phase 2 trials of neoadjuvant treatment intensification in locally advanced rectal cancer have reported promising efficacy signals, but these have not translated into improved cancer outcomes in phase 3 trials. Improvements in phase 2 trial design are needed to reduce these false-positive signals. This systematic review evaluated the design of phase 2 trials of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification in locally advanced rectal cancer.

METHODS AND MATERIALS

The PubMed, EMBASE, MEDLINE, and Cochrane Library databases were searched for published phase 2 trials of neoadjuvant treatment intensification from 2004 to 2016. Trial clinical design and outcomes were assessed, with statistical design and compliance rated using a previously published system. Multivariable meta-regression analysis of pathologic complete response (pCR) was conducted.

RESULTS

We identified 92 eligible trials. Patients with American Joint Committee on Cancer stage II and III equivalent disease were eligible in 87 trials (94.6%). In 43 trials (46.7%), local staging on magnetic resonance imaging was mandated. Only 12 trials (13.0%) were randomized, with 8 having a standard-treatment control arm. Just 51 trials (55.4%) described their statistical design, with 21 trials (22.8%) failing to report their sample size derivation. Most trials (n=84, 91.3%) defined a primary endpoint, but 15 different primary endpoints were used. All trials reported pCR rates. Only 38 trials (41.3%) adequately reported trial statistical design and compliance. Meta-analysis revealed a pooled pCR rate of 17.5% (95% confidence interval, 15.7%-19.4%) across treatment arms of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification and substantial heterogeneity among the reported effect sizes (I² = 55.3%, P<.001). Multivariable meta-regression analysis suggested increased pCR rates with higher radiation therapy doses (adjusted P=.025).

CONCLUSIONS

Improvement in the design of future phase 2 rectal cancer trials is urgently required. A significant increase in randomized trials is essential to overcome selection bias and determine novel schedules suitable for phase 3 testing. This systematic review provides key recommendations to guide future treatment intensification trial design in rectal cancer.

Present and future of metastatic colorectal cancer treatment: A review of new candidate targets

In the last two decades, great efforts have been made in the treatment of metastatic colorectal cancer (mCRC) due to the approval of new target agents for cytotoxic drugs. Unfortunately, a large percentage of patients present with metastasis at the time of diagnosis or relapse after a few months. The complex molecular heterogeneity of this disease is not completely understood; to date, there is a lack of predictive biomarkers that can be used to select subsets of patients who may respond to target drugs. Only the RAS-mutation status is used to predict resistance to anti-epidermal growth factor receptor agents in patients with mCRC. In this review, we describe approved targeted therapies for the management of metastatic mCRC and discuss new candidate targets on the horizon.

Tailored Treatment Strategy for Locally Advanced Rectal Carcinoma Based on the Tumor Response to Induction Chemotherapy: Preliminary Results of the French Phase II Multicenter GRECCAR4 Trial

BACKGROUND

Preoperative radiochemotherapy and total mesorectal excision are the standard-of-care for locally advanced rectal carcinoma, but some patients could be over- or undertreated.

OBJECTIVE

This study aimed to assess the feasibility of radiochemotherapy tailored based on the tumor response to induction chemotherapy (FOLFIRINOX) to obtain a minimum R0 resection rate of 90% in the 4 arms of the study.

DESIGN

This study is a multicenter randomized trial (NCT01333709).

SETTING

This study was conducted at 16 French cancer specialty centers.

PATIENTS

Two hundred six patients with locally advanced rectal carcinoma were enrolled between 2011 and 2014.

INTERVENTIONS

Good responders (≥75% tumor volume reduction) were randomly assigned to immediate surgery (arm A) or standard radiochemotherapy (Cap 50: 50 Gy irradiation and 1600 mg/m oral capecitabine daily) plus surgery (arm B). Poor responders were randomly assigned to Cap 50 (arm C) or intensive radiochemotherapy (Cap 60, 60 Gy irradiation, arm D) before surgery.

OUTCOME MEASURES

The primary end point was a R0 resection rate (circumferential resection margin >1 mm).

STATISTICAL CONSIDERATIONS

The experimental strategies were to be considered effective if at least 28 successes (R0 resection) among 31 patients in each arm of stratum I and 34 successes among 40 patients in each arm of stratum II were reported (Simon 2-stage design).

RESULTS

After induction treatment (good compliance), 194 patients were classified as good (n = 30, 15%) or poor (n = 164, 85%) responders who were included in arms A and B (16 and 14 patients) and arms C and D (113 and 51 patients). The trial was prematurely stopped because of low accrual in arms A and B and recruitment completion in arms C and D. Data from 133 randomly assigned patients were analyzed: 11, 19, 52, and 51 patients in arms A, B, C, and D. Good responders had smaller tumors than poor responders (23 cm vs 45 cm; p < 0.001). The surgical procedure was similar among groups. The R0 resection rates [90% CI] were 100% [70-100], 100% [85-100], 83% [72-91], and 88% [77-95]. Among the first 40 patients, 34 successes were reported in arms C and D (85% R0 resection rate). The circumferential resection margin ≤1 rates were 0%, 0%, 12%, and 5% in arms A, B, C, and D. The rate of transformation from positive to negative circumferential resection margin was 93%.

LIMITATIONS

There was low accrual in arms A and B.

CONCLUSION

Tailoring preoperative radiochemotherapy based on the induction treatment response appears safe for poor responders and promising for good responders. Long-term clinical results are needed to confirm its efficacy. See Video Abstract at http://links.lww.com/DCR/A359.

Panitumumab in Combination With Preoperative Radiation Therapy in Patients With Locally Advanced RAS Wild-type Rectal Cancer: Results of the Multicenter Explorative Single-Arm Phase 2 Study NEORIT

PURPOSE

Studies investigating combinations of anti-epidermal growth factor receptor monoclonal antibodies such as panitumumab or cetuximab with standard chemoradiation therapy protocols in rectal cancer have yielded disappointing results. Because of the supposed negative interaction of epidermal growth factor receptor inhibition and chemoradiation therapy, we conducted a phase 2 study using single-agent panitumumab in combination with radiation therapy in patients with RAS wild-type locally advanced rectal cancer.

METHODS AND MATERIALS

Patients with RAS wild-type locally advanced (clinical stage II or III) rectal cancer localized 0 to 12 cm from the anus were eligible for study participation. The primary objective of the study was to determine pathologic complete response (pCR). Secondary objectives comprised assessing the safety, surgical morbidity, clinical response, tumor downstaging, and tumor regression grading according to Dworak.

RESULTS

A total of 54 patients with a median age of 58 years were treated. In 3.7% of patients, pCR was achieved. Downstaging of the primary tumor or lymph nodes was seen in 65% of patients. No grade ≥2 hematologic toxicity was seen. The most common grade ≥3 nonhematologic toxicities were skin toxicity (24%) and diarrhea (10%).

CONCLUSIONS

Panitumumab in combination with radiation therapy as neoadjuvant treatment for locally advanced rectal cancer showed a favorable toxicity profile but failed to meet the predefined pCR rate to justify further clinical trials.

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.

Targeted Therapy of Colorectal Cancer

Over the past decades, considerable progress has been made in the management of colorectal cancer (CRC), leading to a significant improvement in overall survival. Although part of this success has been rightly attributed to aggressive surgical management and advances in other adjunct treatments, our understanding of the pathogenesis of CRC and emergence of newer molecular targets for colon cancer has created a powerful impact. In this review article, we will discuss various targeted therapies in the management of metastatic CRC (mCRC). In particular, vascular endothelial growth factor (VEGF)- and epidermal growth factor receptor (EGFR)-targeting monoclonal antibodies have become integral components of the first-line treatment strategies for mCRC. Newer agents on the horizon soon to be incorporated in clinical practice will be briefly reviewed as well. Currently, the only predictive biomarker for treatment selection in patients with mCRC is tumor RAS mutational status.

An update on the multimodality of localized rectal cancer

New strategies have reduced the local recurrence (LR) rate and extended the duration of overall survival (OS) in patients with localized rectal cancer (RC) in recent decades. The mainstay of curative treatment remains radical surgery; however, downsizing the tumor by neo-adjuvant chemo-radiotherapy and adjuvant cytotoxic therapy for systemic disease has shown significant additional benefit. The standardization of total mesorectal excision (TME), radiation treatment (RT) dose and fractionation, and optimal timing and sequencing of treatment modalities with the use of prolonged administration of fluoropyrimidine concurrent with RT have significantly decreased the rates of LR in locally advanced rectal cancer (LARC) patients. This review focuses on the optimization of multi-modality therapies in patients with localized RC.

Acute Toxicity and Tumor Response in Locally Advanced Rectal Cancer After Preoperative Chemoradiation Therapy With Shortening of the Overall Treatment Time Using Intensity-Modulated Radiation Therapy With Simultaneous Integrated Boost: A Phase 2 Trial

BACKGROUND AND PURPOSE

This phase 2 study investigated the efficacy and safety of preoperative intensity modulated radiation therapy with a simultaneous integrated boost (IMRT-SIB) without dose escalation, concomitant with standard capecitabine chemotherapy in locally advanced rectal cancer.

METHODS AND MATERIALS

Between January 2014 and March 2015, 51 patients with operable stage II-III rectal adenocarcinoma received preoperative IMRT with pelvic dose of 41.8 Gy and simultaneously delivered 46.2 Gy to T2/3 and 48.4 Gy to T4 tumor in 22 fractions, concomitant with capecitabine, 825 mg/m²/12 hours, including weekends. The primary endpoint was pathologic complete response (pCR).

RESULTS

Fifty patients completed preoperative treatment according to the protocol, and 47 underwent surgical resection. The sphincter preservation rate for the low rectal tumors was 62%, and the resection margins were free in all but 1 patient. Decrease in tumor and nodal stage was observed in 32 (68%) and 39 (83%) patients, respectively, with pCR achieved in 12 (25.5%) patients. There were only 2 G ≥ 3 acute toxicities, with infectious enterocolitis in 1 patient and dermatitis over the sacral area caused by the bolus effect of the treatment table in the second patient.

CONCLUSIONS

Preoperative IMRT-SIB without dose escalation is well tolerated, with a low acute toxicity profile, and can achieve a high rate of pCR and downstaging.

Targeted agents in GI radiotherapy: Clinical efficacy and side effects

Approximately 50% of all patients with cancer receive radiotherapy (RT) at some point during their treatment. Despite the advent of modern imaging and advances in planning and delivering highly-conformal and precise RT, further dose escalation to improve clinical outcome is often limited by the potential side-effects to adjacent tissues. Addition of chemotherapy to radiotherapy (CRT) has led to significant clinical improvements in many gastrointestinal malignancies but at the expense of increased toxicity as most chemotherapy drugs lack specificity. Targeted agents modulate specific biological pathways and can potentially enhance RT efficacy. However, so far, the majority of clinical studies incorporating targeted agents into RT and CRT have produced disappointing results in gastrointestinal malignancies. Also, we lack validated biomarkers and methods for monitoring and predicting the efficacy of these agents when combined with RT/CRT. In the present article, we will review the most important targeted therapies, and examine the efficacy and toxicity of these agents when combined with RT/CRT in gastrointestinal malignancies. The shortcomings as well as future challenges and perspectives for the successful use of these compounds with RT/CRT in future trials will also be outlined.

Drug Combinations in Preoperative Chemoradiation for Rectal Cancer

Preoperative radiotherapy has an accepted role in reducing the risk of local recurrence in locally advanced resectable rectal cancer, particularly when the circumferential resection margin is breached or threatened, according to magnetic resonance imaging. Fluoropyrimidine-based chemoradiation can obtain a significant down-sizing response and a curative resection can then be achieved. Approximately, 20% of the patients can also obtain a pathological complete response, which is associated with less local recurrences and increased survival. Patients who achieve a sustained complete clinical response may also avoid radical surgery. In unresectable or borderline resectable tumors, around 20% of the patients still fail to achieve a sufficient down-staging response with the current chemoradiation schedules. Hence, investigators have aspired to increase pathological complete response rates, aiming to improve curative resection rates, enhance survival, and potentially avoid mutilating surgery. However, adding additional cytotoxic or biological agents have not produced dramatic improvements in outcome and often led to excess surgical morbidity and higher levels of acute toxicity, which effects on compliance and in the global efficacy of chemoradiation.

The best timing for administering systemic chemotherapy in patients with locally advanced rectal cancer

Over the past several decades, outcomes for patients with rectal cancer have improved considerably. However, several questions have emerged as survival times have lengthened and quality of life has improved for these patients. Currently patients with locally advanced rectal cancer (LARC) are often recommended multimodality therapy with fluoropyrimidine-based chemotherapy (CT) and radiation followed by total mesorectal excision (TME), with consideration given to FOLFOX before chemoradiotherapy (CRT). Recently, Garcia-Aguilar and colleagues reported in Lancet Oncology that the addition of mFOLFOX6 administered between CRT and surgery affected the number of patients achieving pathologic complete response (pathCR), which is of great interest from the standpoint of pursuit of optimal timing of systemic CT delivery. This was a multicenter phase II study consisting of 4 sequential treatment groups of patients with LARC, and they reported that patients given higher number CT cycles between CRT and surgery achieved higher rates of pathCR than those given standard treatment. There was no association between response improvement and tumor progression, increased technical difficulty, or surgical complications. Ongoing phase III clinical trial further assessing this strategy might result in a paradigm shift.

Novel therapeutic agents in the treatment of metastatic colorectal cancer

Over the past couple of decades considerable progress has been made in the management of metastatic colorectal cancers (mCRC) leading to a significant improvement in five-year survival. Although part of this success has been rightly attributed to aggressive surgical management and advances in other adjunct treatments, our understanding of the pathogenesis of cancer and emergence of newer molecular targets for colon cancer has created a powerful impact. In this review article we will discuss various targeted therapies in the management of mCRC. Newer agents on the horizon soon to be incorporated in clinical practice will be briefly reviewed as well.

Optimal therapy for resectable rectal cancer

A lot can be gained by improving our understanding of the optimal sequence of existing therapies in rectal cancer, with the more difficult task of balancing the morbidity of recurrence with the morbidity of prescribed therapies that are particularly toxic owing to tumour location. This review aims to highlight a recent shift in treatment strategies in the opposite direction, with a focus on earlier, more intense systemic treatments with reduced local therapies. Understanding the rationale for and evidence to support this shift will help identify gaps, shape future trials, and ultimately answer the question of whether this is indeed the right path to follow with regards to maintaining local control rates and long-term outcomes for patients, and improving distal disease control and local treatment-related morbidities without compromising quality of life.

Radio-Immunotherapy-Induced Immunogenic Cancer Cells as Basis for Induction of Systemic Anti-Tumor Immune Responses - Pre-Clinical Evidence and Ongoing Clinical Applications

Radiotherapy (RT) primarily aims to locally destroy the tumor via the induction of DNA damage in the tumor cells. However, the so-called abscopal, namely systemic and immune–mediated, effects of RT move over more and more in the focus of scientists and clinicians since combinations of local irradiation with immune therapy have been demonstrated to induce anti-tumor immunity. We here summarize changes of the phenotype and microenvironment of tumor cells after exposure to irradiation, chemotherapeutic agents, and immune modulating agents rendering the tumor more immunogenic. The impact of therapy-modified tumor cells and damage-associated molecular patterns on local and systemic control of the primary tumor, recurrent tumors, and metastases will be outlined. Finally, clinical studies affirming the bench-side findings of interactions and synergies of radiation therapy and immunotherapy will be discussed. Focus is set on combination of radio(chemo)therapy (RCT) with immune checkpoint inhibitors, growth factor inhibitors, and chimeric antigen receptor T-cell therapy. Well-deliberated combination of RCT with selected immune therapies and growth factor inhibitors bear the great potential to further improve anti-cancer therapies.

Recent advances in multidisciplinary approach for rectal cancer

Surgery is a major treatment option for rectal cancer, and total mesorectal excision has been demonstrated to be advantageous in terms of oncological outcome and thus has been the standard surgical approach. Radiotherapy before or after radical surgery is the optimal treatment to control local recurrence of advanced rectal cancer. To date, in many countries, the combination of neoadjuvant concurrent chemotherapy and radiotherapy is considered the standard therapy. A more recent interest in neoadjuvant therapy has been the use of oxaliplatin or targeted agents for neoadjuvant chemoradiotherapy. However, despite many trials of oxaliplatin and targeted agents, 5-FU-based concurrent chemoradiotherapy has remained the only standard treatment option. Postoperative adjuvant chemotherapy with neoadjuvant chemoradiotherapy or induction chemotherapy with neoadjuvant chemoradiotherapy may further improve patient survival, as some clinical studies recently indicated. In Japan, neoadjuvant therapy is not the standard treatment method, because surgery with lateral lymph node dissection is usually performed and this type of surgery may reduce recurrence rate as does radiation therapy. The phase III study to evaluate the oncological effect of the Japanese standard operation (mesorectal excision, ME) with lateral lymph node dissection in comparison with ME alone for clinical stage II and III lower rectal cancer is currently ongoing.