Cetuximab and chemoradiation for rectal cancer--is the water getting muddy?

Rectal squamous cell carcinoma treated with neoadjuvant fluorouracil, oxaliplatin, cetuximab, and radiation: A case report of pathological complete response

RATIONALE

Treatment strategies for rectal squamous cell carcinoma (rSCC) are yet to be established, given its rarity. Although squamous cell carcinoma has been reported to be highly sensitive to cetuximab and radiation, there is no report of combination therapy of cetuximab and radiation for rSCC. In this study, we firstly reported a case of rSCC in which a complete response was achieved with the original chemoradiotherapy comprising oxaliplatin, S-1, cetuximab, and simultaneous radiation.

PATIENT CONCERNS

A 46-year-old women presented to our hospital with lower abdominal pain and fatigue.

DIAGNOSES

Based on tumor marker analyses, histological examination of biopsy specimens, and comprehensive imaging, the patient was diagnosed with rSCC.

INTERVENTIONS

Neoadjuvant chemoradiotherapy (50.4 Gy) was administered in 28 fractions, along with concurrent chemotherapy comprising SOX (S-1: 80 mg/m2, days 1-5 and 8-12, oxaliplatin: 85 mg/m2, day 1) and cetuximab (400 mg/m2, day 1, 250 mg/m2, after day 8).

OUTCOMES

Five weeks after chemoradiation, the patient underwent laparoscopic partial intersphincteric resection, achieving a complete pathological response.

LESSONS

This case firstly highlights the usefulness of SOX plus cetuximab combined with radiation in the treatment of locally advanced rSCC. However, a large-scale study is required to establish safe and effective treatment regimens.

Novel radiation and targeted therapy combinations for improving rectal cancer outcomes

Neoadjuvant radiotherapy (RT) is commonly used as standard treatment for rectal cancer. However, response rates are variable and survival outcomes remain poor, highlighting the need to develop new therapeutic strategies. Research is focused on identifying novel methods for sensitising rectal tumours to RT to enhance responses and improve patient outcomes. This can be achieved through harnessing tumour promoting effects of radiation or preventing development of radio-resistance in cancer cells. Many of the approaches being investigated involve targeting the recently published new dimensions of cancer hallmarks. This review article will discuss key radiation and targeted therapy combination strategies being investigated in the rectal cancer setting, with a focus on exploitation of mechanisms which target the hallmarks of cancer.

Inhibition of DNA-PK may improve response to neoadjuvant chemoradiotherapy in rectal cancer

Treatment of locally advanced rectal cancer includes chemoradiation and surgery, but patient response to treatment is variable. Patients who have a complete response have improved outcomes; therefore, there is a critical need to identify mechanisms of resistance to circumvent them. DNA-PK is involved in the repair of DNA double-strand breaks caused by radiation, which we found to be increased in rectal cancer after treatment. We hypothesized that inhibiting this complex with a DNA-PK inhibitor, Peposertib (M3814), would improve treatment response. We assessed pDNA-PK in a rectal cancer cell line and mouse model utilizing western blotting, viability assays, γH2AX staining, and treatment response. The three treatment groups were: standard of care (SOC) (5-fluorouracil (5FU) with radiation), M3814 with radiation, and M3814 with SOC. SOC treatment of rectal cancer cells increased pDNA-PK protein and increased γH2AX foci, but this was abrogated by the addition of M3814. Mice with CT26 tumors treated with M3814 with SOC did not differ in average tumor size but individual tumor response varied. The clinical complete response rate improved significantly with the addition of M3814 but pathological complete response did not. We investigated alterations in DNA repair and found that Kap1 and pATM are increased after M3814 addition suggesting this may mediate resistance. When the DNA-PK inhibitor, M3814, is combined with SOC treatment, response improved in some rectal cancer models but an increase in other repair mechanisms likely diminishes the effect. A clinical trial is ongoing to further explore the role of DNA-PK inhibition in rectal cancer treatment.

Locally Advanced Rectal Cancer: What We Learned in the Last Two Decades and the Future Perspectives

The advancement in surgical techniques, optimization of systemic chemoradiotherapy, and development of refined diagnostic and imaging modalities have brought a phenomenal shift in the treatment of the locally advanced rectal cancer. Although each therapeutic option has shown substantial progress in their field, it is finding their ideal amalgamation which has baffled the clinician and researchers alike. In the effort to identifying the perfect salutary treatment plan, we have even shifted our attention from the trimodal approach to non-operative "watchful waiting" to more recent individualized care. In this article, we acknowledge the scientific progress in the management of locally advanced rectal cancer and compare the opportunities as well as the obstacles while implementing them clinically. We also explore the current challenges and controversies surrounding the multidisciplinary approach and highlight the new trends and recent advances with an ultimate goal to improve the patients' quality of life.

Efficacy and safety of anti-epidermal growth factor receptor agents for the treatment of oesophageal cancer: a systematic review and meta-analysis

OBJECTIVES

Despite remarkable advances in the treatment of oesophageal cancer (OC), the role of antiepidermal growth factor receptor (anti-EGFR) agents in treating OC remains controversial. Herein, a systematic review and meta-analysis were conducted to elucidate the efficacy and safety of anti-EGFR agents in patients with OC.

DESIGN

Meta-analysis of randomised controlled trials (RCTs) identified by searching the PubMed, Embase, Web of Science, ClinicalTrials.gov, Cochrane Library, Chinese Biology Medicine, China National Knowledge Infrastructure and Wanfang Data Knowledge Service Platform databases from inception to December 2019. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

SETTING

RCTs from any country and healthcare setting.

PARTICIPANTS

Patients with OC.

INTERVENTIONS

Combination therapy with anti-EGFR agents and conventional treatments versus conventional treatments alone in patients with OC.

PRIMARY AND SECONDARY OUTCOME MEASURES

Overall survival (OS) and progression-free survival (PFS) were primary outcome measures, and objective response rate (ORR), disease control rate (DCR) and treatment toxicities were secondary outcome measures.

RESULTS

In total, 25 RCTs comprising 3406 patients with OC were included. Overall, anti-EGFR treatment significantly improved the OS (HR: 0.81, 95% CI 0.74 to 0.89, p<0.00001), ORR (relative risk (RR): 1.33, 95% CI 1.16 to 1.52, p<0.0001) and DCR (RR: 1.22, 95% CI 1.11 to 1.34, p<0.0001) but not PFS (HR: 0.91, 95% CI 0.76 to 1.08, p=0.26). Anti-EGFR treatment was significantly associated with higher incidences of myelosuppression, diarrhoea, acne-like rash and hypomagnesaemia.

CONCLUSIONS

Overall, anti-EGFR agents have positive effects on OS, the ORR and DCR in OC. However, considering the high incidence of adverse effects, such as myelosuppression, diarrhoea, acne-like rashes and hypomagnesaemia, careful monitoring of patients with OC is recommended during anti-EGFR treatment.

TRIAL REGISTRATION NUMBER

CRD42020169230.

Cetuximab for esophageal cancer: an updated meta-analysis of randomized controlled trials

BACKGROUND

Increasing evidence indicates that cetuximab (CET) combined with chemoradiotherapy may be effective for patients with esophageal cancer. However, the recent results are still contradictory and no consensus has yet been reached on this issue. To evaluate the clinical effects and safety of CET, we conducted an updated meta-analysis by retrieving published data up to June 2018.

METHODS

A comprehensive literature search was performed in several electronic databases, including PubMed, Embase, the Cochrane Library, CNKI database and Chinese Biomedicine Database using subject terms and free terms. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to determine the efficiency and safety of CET.

RESULTS

This meta-analysis included 10 randomized controlled trials (RCTs). Five RCTs reported localized esophageal cancer and other five RCTs reported metastatic esophageal cancer. For these patients with localized esophageal cancer, CET could not significantly improve the response rate, overall survival and progression-free survival (PFS, 1-5 years). But CET treatment might increase the incidences of diarrhea (OR = 2.07; CI = 1.01-4.25) and rash (OR = 16.91; CI = 3.20-89.42). For other patients with metastatic esophageal cancer, the addition of CET significantly increased the response rate (OR = 3.34; CI = 1.90-5.88), disease control rate (OR = 2.92; CI = 1.49-5.71) and 2-year overall survival (OR = 2.78; CI = 1.20-6.46) compared with the control group. However, CET could not improve the 1-year overall survival and might make patients with metastatic esophageal cancer more susceptible to rash (OR = 5.50; CI = 2.14-14.14). No significant differences in other adverse effects were found between the two groups.

CONCLUSIONS

Our findings suggested that adding CET to multimodal therapy significantly improved response rate and disease control rate for patients with metastatic esophageal cancer rather than patients with localized esophageal cancer. CET might be a safe therapeutic choice, but CET failed to significantly improve the overall survival and PFS for patients with localized or metastatic esophageal cancer.

Outcome and prognostic factors in 593 non-metastatic rectal cancer patients: a mono-institutional survey

This retrospective study was undertaken to provide more modern data of real-life management of non-metastatic rectal cancer, to compare therapeutic strategies, and to identify prognostic factors of overall survival (OS) in a large cohort of patients. Data on efficacy and on acute/late toxicity were retrospectively collected. Patients were diagnosed a non-metastatic rectal cancer between 2004 and 2015, and were treated at least with radiotherapy. OS was correlated with patient, tumor and treatment characteristics with univariate and multivariate analyses. Data of 593 consecutive non-metastatic rectal cancer patients were analyzed. Median follow-up was 41 months. Median OS was 9 years. Radiotherapy was delivered in pre-operative (n = 477, 80.5%), post-operative (n = 75, 12.6%) or exclusive (n = 41, 6.9%) setting. In the whole set of patients, age, nutritional condition, tumor stage, tumor differentiation, and surgery independently influenced OS. For patients experiencing surgery, OS was influenced by age, tumor differentiation and nodal status. Surgical resection is the cornerstone treatment for locally-advanced rectal cancer. Poor tumor differentiation and node involvement were identified as major predictive factor of poor OS. The research in treatment intensification and in identification of radioresistance biomarkers should therefore probably be focused on this particular subset of patients.

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.

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.

Therapeutic approaches in the management of locally advanced rectal cancer

Combined-modality therapy, using radiotherapy and chemotherapy with surgery, has been the traditional therapeutic algorithm for locally advanced rectal cancer. Standard of care in the United States has evolved to include neoadjuvant concurrent chemotherapy and radiotherapy followed by surgical excision and adjuvant chemotherapy. This approach has led to a significant improvement in local recurrences (LR), to the point where distant sites are the more common site of failure. Further improvements in local control have failed to improve overall survival. This article reviews historical trials that shifted the treatment paradigm to the current standard of care, as well as recent research trials, which have sought to incorporate new treatment methodologies, and treatment agents to improve outcomes. Finally this article describes ongoing studies and their potential impact on the future of therapeutic management of locally-advanced rectal cancer.

Genotypic characteristics of resistant tumors to pre-operative ionizing radiation in rectal cancer

Due to a wide range of clinical response in patients undergoing neo-adjuvant chemoradiation for rectal cancer it is essential to understand molecular factors that lead to the broad response observed in patients receiving the same form of treatment. Despite extensive research in this field, the exact mechanisms still remain elusive. Data raging from DNA-repair to specific molecules leading to cell survival as well as resistance to apoptosis have been investigated. Individually, or in combination, there is no single pathway that has become clinically applicable to date. In the following review, we describe the current status of various pathways that might lead to resistance to the therapeutic applications of ionizing radiation in rectal cancer.

Cetuximab induces eme1-mediated DNA repair: a novel mechanism for cetuximab resistance

Overexpression of the epidermal growth factor receptor (EGFR) is observed in a large number of neoplasms. The monoclonal antibody cetuximab/Erbitux is frequently applied to treat EGFR-expressing tumors. However, the application of cetuximab alone or in combination with radio- and/or chemotherapy often yields only little benefit for patients. In the present study, we describe a mechanism that explains resistance of both tumor cell lines and cultured primary human glioma cells to cetuximab. Treatment of these cells with cetuximab promoted DNA synthesis in the absence of increased proliferation, suggesting that DNA repair pathways were activated. Indeed, we observed that cetuximab promoted the activation of the DNA damage response pathway and prevented the degradation of essential meiotic endonuclease 1 homolog 1 (Eme1), a heterodimeric endonuclease involved in DNA repair. The increased levels of Eme1 were necessary for enhanced DNA repair, and the knockdown of Eme1 was sufficient to prevent efficient DNA repair in response to ultraviolet-C light or megavoltage irradiation. These treatments reduced the survival of tumor cells, an effect that was reversed by cetuximab application. Again, this protection was dependent on Eme1. Taken together, these results suggest that cetuximab initiates pathways that result in the stabilization of Eme1, thereby resulting in enhanced DNA repair. Accordingly, cetuximab enhances DNA repair, reducing the effectiveness of DNA-damaging therapies. This aspect should be considered when using cetuximab as an antitumor agent and suggests that Eme1 is a negative predictive marker.

Gefitinib enhances the effects of combined radiotherapy and 5-fluorouracil in a colorectal cancer cell line

PURPOSE

In a phase I/II trial, patients with locally advanced rectal cancer received preoperative radiotherapy (RT) and concurrent with 5-fluorouracil (5-FU) and gefitinib. Results were promising. To elucidate the molecular and biological effects, we replicated the schedule in the LoVo human colorectal adenocarcinoma cell line.

METHODS

RT (2 Gy daily for 3 days), 5-FU (0.3, 0.6, 1.25, 2.5, 5, 10 μM) and gefitinib (0.2, 0.4, 0.8 μM) were administered alone, in double combinations and all together. We assessed viable cells, cell cycle, cyclin, p53 and p21 expression, signalling pathways by means of phosphorylated epidermal growth factor receptor (p-EGFR), p-AKT and p-ERK 1-2 and clonogenic capacity.

RESULTS

RT and 5-FU were cytotoxic. Gefitinib was cytostatic. RT reduced clonogenic capacity more than 5-FU. 5-FU induced more cell death than RT, but surviving cells were proliferative (cyclins and p-EGFR increased). 5-FU + RT had a synergistic effect. Gefitinib, enhancing G1 accumulation, reduced proliferation of cells surviving 5-FU and 5-FU + RT. It slightly increased the cytotoxicity of RT and 5-FU.

CONCLUSIONS

As gefitinib limited the proliferation rate of cells surviving 5-FU and 5-FU + RT in the LoVo cell line, it may be a useful addition to chemotherapy and RT in rectal cancer patients.

Current controversies in neoadjuvant chemoradiation of rectal cancer

Total mesorectal excision with preoperative radiation and chemotherapy provide the lowest local recurrence rates for rectal cancer. Timing of surgery after preoperative chemoradiation is being increased to optimize tumor downstaging. In cases of complete clinical response from chemoradiation, permissive observation without resection is being investigated. Significant anorectal dysfunction results from low anterior resection and radiation. Good prognostic tumor characteristics are being investigated with the aim of selecting cases for whom preoperative radiation may be avoided. Preoperative and postoperative radiation provides improved local cancer control for superficial cancers removed by local excision.

Challenges in the neoadjuvant treatment of rectal cancer: balancing the risk of recurrence and quality of life

The management of patients with rectal cancer has improved substantially-assisted by refinements in surgical technique, the increasing accuracy of preoperative imaging, more precise delivery of radiotherapy¸and more informative feedback from the histopathologist. Multidisciplinary teams have been the key to this success. Future challenges facing multidisciplinary teams include individually tailoring therapy - in particular in deciding who does and does not need radiotherapy, utilising new radiotherapy techniques such as intensity-modulated radiotherapy and image-guided radiotherapy and new systemic therapies, and electing patients for whom chemoradiotherapy might be potentially curative without surgical resection after complete clinical response. Hence, there is an increasing focus on developing predictive and prognostic molecular biomarkers. This paper explores the background to common variations in practice, and the current and future challenges in the neoadjuvant treatment of rectal cancer.

The status of targeted agents in the setting of neoadjuvant radiation therapy in locally advanced rectal cancers

Radiotherapy has a longstanding and well-defined role in the treatment of resectable rectal cancer to reduce the historically high risk of local recurrence. In more advanced borderline or unresectable cases, where the circumferential resection margin (CRM) is breached or threatened according to magnetic resonance imaging (MRI), despite optimized local multimodality treatment and the gains achieved by modern high quality total mesorectal excision (TME), at least half the patients fail to achieve sufficient downstaging with current schedules. Many do not achieve an R0 resection. In less locally advanced cases, even if local control is achieved, this confers only a small impact on distant metastases and a significant proportion of patients (30-40%) still subsequently develop metastatic disease. In fact, distant metastases have now become the predominant cause of failure in rectal cancer. Therefore, increasing the intensity and efficacy of chemotherapy and chemoradiotherapy by integrating additional cytotoxics and biologically targetted agents seems an appealing strategy to explore-with the aim of enhancing curative resection rates and improving distant control and survival. However, to date, we lack validated biomarkers for these biological agents apart from wild-type KRAS. For cetuximab, the appearance of an acneiform rash is associated with response, but low levels of magnesium appear more controversial. There are no molecular biomarkers for bevacizumab. Although some less invasive clinical markers have been proposed for bevacizumab, such as circulating endothelial cells (CECS), circulating levels of VEGF and the development of overt hypertension, these biomarkers have not been validated and are observed to emerge only after a trial of the agent. We also lack a simple method of ongoing monitoring of 'on target' effects of these biological agents, which could determine and pre-empt the development of resistance, prior to radiological and clinical assessessments or even molecular imaging. These shortcomings probably explain our current relative lack of success in the arena of combining these agents with chemoradiation.

Selecting patients with locally advanced rectal cancer for neoadjuvant treatment strategies

Rectal cancer remains a significant problem worldwide. Outcomes vary significantly according to the stage of disease and prognostic factors, including the distance of the tumor from the circumferential resection margin. Accurate staging, including high-resolution magnetic resonance imaging, allows stratification of patients into low-, moderate-, and high-risk disease; this information can be used to inform multidisciplinary team decisions regarding the role of neoadjuvant therapy. Both neoadjuvant short-course radiotherapy and long-course chemoradiation reduce the risk of local recurrence compared with surgery alone, but they have little impact on survival. Although there remains a need to reduce overtreatment of those patients at moderate risk, evaluation of intensified regimens for those with high-risk disease is still required to reduce distant failure rates and improve survival in these patients with an otherwise poor prognosis.

Epidermal growth factor receptor expression as prognostic marker in patients with anal carcinoma treated with concurrent chemoradiation therapy

PURPOSE

To investigate the prognostic value of epidermal growth factor receptor (EGFR) expression in pretreatment tumor biopsy specimens of patients with anal cancer treated with concurrent 5-fluorouracil and mitomycin C-based chemoradiation therapy (CRT).

METHODS AND MATERIALS

Immunohistochemical staining for EGFR was performed in pretreatment biopsy specimens of 103 patients with anal carcinoma. EGFR expression was correlated with clinical and histopathologic characteristics and with clinical endpoints, including local failure-free survival (LFFS), colostomy-free survival (CFS), distant metastases-free survival (DMFS), cancer-specific survival (CSS), and overall survival (OS).

RESULTS

EGFR staining intensity was absent in 3%, weak in 23%, intermediate in 36% and intense in 38% of the patients. In univariate analysis, the level of EGFR staining was significantly correlated with CSS (absent/weak vs intermediate/intense expression: 5-year CSS, 70% vs 86%, P=.03). As a trend, this was also observed for DMFS (70% vs 86%, P=.06) and LFFS (70% vs 87%, P=.16). In multivariate analysis, N stage, tumor differentiation, and patients' sex were independent prognostic factors for CSS, whereas EGFR expression only reached borderline significance (hazard ratio 2.75; P=.08).

CONCLUSION

Our results suggest that elevated levels of pretreatment EGFR expression could be correlated with favorable clinical outcome in anal cancer patients treated with CRT. Further studies are warranted to elucidate how EGFR is involved in the response to CRT.

Chemoradiotherapy with or without cetuximab in patients with oesophageal cancer (SCOPE1): a multicentre, phase 2/3 randomised trial

BACKGROUND

Definitive chemoradiotherapy (CRT) is an alternative to surgery for the curative treatment of oesophageal carcinoma. The SCOPE1 trial aimed to investigate the addition of cetuximab to cisplatin and fluoropyrimidine-based definitive CRT in patients with localised oesophageal squamous-cell cancer and adenocarcinomas to assess activity, safety, and feasibility of use.

METHODS

In this multicentre, randomised, open-label, phase 2/3 trial, we recruited patients aged 18 years and older from UK radiotherapy centres who had non-metastatic, histologically confirmed carcinoma of the oesophagus (adenocarcinoma, squamous-cell, or undifferentiated; WHO status 0-1; stage I-III disease) and been selected to receive definitive CRT. Patients were randomly assigned (1:1) via a central computerised system using stratified minimisation (with an 80:20 random element) to receive CRT alone or CRT with cetuximab (400 mg/m(2) on day 1 followed by 250 mg/m(2) weekly), stratified by recruiting hospital, primary reason for not having surgery, tumour histology, and tumour stage. CRT consisted of cisplatin 60 mg/m(2) (day 1) and capecitabine 625 mg/m(2) twice daily (days 1-21) for four cycles; cycles three and four were given concurrently with 50 Gy in 25 fractions of radiotherapy. The primary endpoint was the proportion of patients who were treatment failure free at week 24 for the phase 2 trial and overall survival for the phase 3 trial, both measured from randomisation. We analysed data by intention to treat. This trial is an International Standard Randomised Controlled Trial, number 47718479.

FINDINGS

258 patients (129 assigned to each treatment group) from 36 UK centres were recruited between Feb 7, 2008, and Feb 22, 2012. Recruitment was stopped without continuation to phase 3 because the trial met criteria for futility, but we continued to follow-up recruited patients until all had reached at least 24-week follow-up (median follow-up of patients who survived was 16.8 months [IQR 11.2-24.5]). Fewer patients were treatment failure free at 24 weeks in the CRT plus cetuximab group (79 of 119 patients [66·4%, 90% CI 58·6-73·6]) than in the CRT only group (93 of 121 patients [76.9%, 69.7-83.0]). The CRT plus cetuximab group also had shorter median overall survival (22.1 months [95% CI 15.1-24.5] vs 25.4 months [20.5-37.9]; adjusted HR 1.53 [95% CI 1.03-2.27]; p=0.035). Patients who received CRT plus cetuximab had more non-haematological grade 3 or 4 toxicities (102 [79%] of 129 patients vs 81 [63%] of 129 patients; p=0.004). The most common grade 3 or 4 toxicities were low white blood cell count (14 [11%] in the CRT plus cetuximab group vs 21 [16%] in the CRT only group), low absolute neutrophil count (15 [12%] vs 24 [19%]), fatigue (26 [20%] vs 25 [19%]), and dysphagia (35 [27%] vs 37 [29%]).

INTERPRETATION

The addition of cetuximab to standard chemotherapy and radiotherapy cannot be recommended for patients with oesophageal cancer suitable for definitive CRT.

FUNDING

Cancer Research UK.

Long-term results of 2 adjuvant trials reveal differences in chemosensitivity and the pattern of metastases between colon cancer and rectal cancer

Two identical randomized controlled trials designed to optimize adjuvant treatment of colon cancer (CC) (n =855) and rectal cancer (RC) (n = 796) were performed. Long-term evaluation confirmed that the addition of folinic acid (FA) to 5-fluorouracil (5-FU) improved 7-year overall survival (OS) in CC but not in RC and revealed different patterns of recurrence in patients with CC and those with RC.

BACKGROUND

Our aim was to compare long-term results of adjuvant treatment of colon cancer (CC) and rectal cancer (RC). Adjuvant chemotherapy of CC improved overall survival (OS), whereas that of RC remained at the level achieved by 5-fluorouracil (5-FU).

METHODS

We separately conducted 2 identically designed adjuvant trials in CC and RC. Patients were assigned to adjuvant chemotherapy with 5-FU alone, 5-FU + folinic acid (FA), or 5-FU + interferon-alfa. The first study enrolled patients with stage IIb/III CC, and the second study enrolled patients with stage II/III RC. All patients with RC received postoperative irradiation.

RESULTS

Median follow-up for all patients with CC (n = 855) and RC (n = 796) was 4.9 years. The pattern and frequency of recurrence differed significantly, especially lung metastases, which occurred more frequently in RC (12.7%) than in CC (7.3%; P < .001). Seven-year OS rates for 5-FU, 5-FU + FA, and 5-FU + IFN-alfa were 54.1% (95% confidence interval [CI], 46.5-61.0), 66.8% (95% CI, 59.4-73.1), and 56.7% (95% CI, 49.3-63.4) in CC and 50.6% (95% CI, 43.0-57.7), 56.3% (95% CI, 49.4-62.7), and 54.8% (95% CI, 46.7-62.2) in RC, respectively. A subgroup analysis pointed to a reduced local recurrence (LR) rate and an increased OS by the addition of FA in stage II RC (n = 271) but not in stage III RC (n = 525).

CONCLUSION

FA increased 7-year OS by 12.7 percentage points in CC but was not effective in RC. Based on these results and the pattern of metastases, our results suggest that the chemosensitivity of CC and RC may be different. Strategies different from those used in CC may be successful to decrease the frequency of distant metastases in RC in the future.

Effect of neoadjuvant cetuximab, capecitabine, and radiotherapy for locally advanced rectal cancer: results of a phase II study

PURPOSE

The aim of this study was to investigate the efficacy and safety of neoadjuvant cetuximab, capecitabine, and radiotherapy for patients with locally advanced rectal cancer.

METHODS

Sixty-three eligible patients were selectively enrolled in this study. Neoadjuvant treatment consisted of cetuximab and capecitabine for 6 weeks and radiotherapy for 5 weeks. Surgical resection was performed 6-8 weeks after the completion of neoadjuvant treatment. KRAS mutation statuses were analyzed retrospectively after the cetuximab treatment. All the patients underwent a standardized postoperative follow-up for at least 3 years.

RESULTS

A pathological complete response (pCR) was achieved in eight patients (12.7 %). Overall down-staging was found in 49 patients (77.8 %). The 3-year disease-free survival (DFS) rate and overall survival (OS) rate was 76.2 % and 81.0 %, respectively. The most common adverse events during neoadjuvant treatment were acneiform skin rash (82.5 %), radiodermatitis (46.0 %), and diarrhea (36.5 %). KRAS mutations were detected in 19 of 63 (31.2 %) tumors. The down-staging rate in patients with KRAS wild-type (WT) was significantly higher than patients with KRAS mutation (P = 0.020). There was no significant difference in the pCR rate, 3-year DFS rate or 3-year OS rate between KRAS WT patients and KRAS-mutated patients.

CONCLUSION

Neoadjuvant treatment with cetuximab and capecitabine-based chemoradiotherapy is safe and well tolerated. The pCR rate, 3-year DFS rate and OS rate are not superior to the rate of neoadjuvant chemoradiotherapy using two or more cytotoxic agents. The KRAS WT is highly associated with tumor down-staging to cetuximab plus capecitabine-based CRT in patients with LARC.

Toward the non-surgical management of locally advanced rectal cancer

Neoadjuvant short-course radiotherapy and long-course chemoradiation (CRT) reduce local recurrence rates when compared to surgery alone and remain widely accepted as standard of care for patients with locally advanced rectal cancer. However, surgery is not without complications and a non-surgical approach in carefully selected patients warrants evaluation. A pathological complete response to CRT is associated with a significant improvement in survival and it has been suggested that a longer time interval between the completion of CRT and surgery increases tumor downstaging. Intensification of neoadjuvant treatment regimens to increase tumor downstaging has been evaluated in a number of clinical trials and more recently the introduction of neoadjuvant chemotherapy prior to CRT has demonstrated high rates of radiological tumor regression. Careful selection of patients using high-resolution MRI may allow a non-surgical approach in a subgroup of patients achieving a complete response to neoadjuvant therapies after an adequate time period. Clearly this needs prospective evaluation within a clinical trial setting, incorporating modern imaging techniques, and tissue biomarkers to allow accurate prediction and assessment of response.

Current status of intensified neo-adjuvant systemic therapy in locally advanced rectal cancer

The addition of 5-fluorouracil (5-FU) or its prodrug capecitabine to radiotherapy (RT) is a standard approach in the neo-adjuvant treatment of patients with rectal tumors extending beyond the muscularis propria (stage II) and/or with clinical evidence of regional lymph node metastases (stage III). According to European randomized trials, the combined treatment modality resulted in favorable local control rates as compared with radiotherapy (RT) alone, but no improvement was found regarding the occurrence of distant metastases or overall survival. In an effort to further enhance the response rates and to decrease the high incidence of distant metastases in locally advanced rectal cancer patients, the addition of other chemotherapeutical drugs and biologic agents as radiation sensitizers to neo-adjuvant 5-FU based chemoradiotherapy (CRT) has been recently investigated. The role of those agents is however questionable as first results from phase III data do not show improvement on pathologic complete remission and circumferential resection margin negative resection rates as compared to 5-FU based CRT, nevertheless an increased toxicity.

Multidisciplinary treatment of patients with rectal cancer: Development during the past decades and plans for the future

In rectal cancer treatment, both the local primary and the regional and systemic tumour cell deposits must be taken care of in order to improve survival. The three main treatments, surgery, radiotherapy, and chemotherapy, each with their own advantages and limitations, must then be combined to improve results. Several large randomized trials have shown that combinations of the modalities have markedly reduced the loco-regional recurrences, but have not yet had any major influence on overall survival. The best integration of the weakest modality, to date the drugs (conventional cytotoxics and biologicals), is not known. A new generation of trials exploring the best sequence of treatments is required. Furthermore, treatment of rectal cancer is administered to populations of individuals, based upon clinical factors and imaging, and can presently not be further individualized. There is an urgent need to develop response predictors.

Multicenter randomized phase II clinical trial comparing neoadjuvant oxaliplatin, capecitabine, and preoperative radiotherapy with or without cetuximab followed by total mesorectal excision in patients with high-risk rectal cancer (EXPERT-C)

PURPOSE

To evaluate the addition of cetuximab to neoadjuvant chemotherapy before chemoradiotherapy in high-risk rectal cancer.

PATIENTS AND METHODS

Patients with operable magnetic resonance imaging-defined high-risk rectal cancer received four cycles of capecitabine/oxaliplatin (CAPOX) followed by capecitabine chemoradiotherapy, surgery, and adjuvant CAPOX (four cycles) or the same regimen plus weekly cetuximab (CAPOX+C). The primary end point was complete response (CR; pathologic CR or, in patients not undergoing surgery, radiologic CR) in patients with KRAS/BRAF wild-type tumors. Secondary end points were radiologic response (RR), progression-free survival (PFS), overall survival (OS), and safety in the wild-type and overall populations and a molecular biomarker analysis.

RESULTS

One hundred sixty-five eligible patients were randomly assigned. Ninety (60%) of 149 assessable tumors were KRAS or BRAF wild type (CAPOX, n = 44; CAPOX+C, n = 46), and in these patients, the addition of cetuximab did not improve the primary end point of CR (9% v 11%, respectively; P = 1.0; odds ratio, 1.22) or PFS (hazard ratio [HR], 0.65; P = .363). Cetuximab significantly improved RR (CAPOX v CAPOX+C: after chemotherapy, 51% v 71%, respectively; P = .038; after chemoradiation, 75% v 93%, respectively; P = .028) and OS (HR, 0.27; P = .034). Skin toxicity and diarrhea were more frequent in the CAPOX+C arm.

CONCLUSION

Cetuximab led to a significant increase in RR and OS in patients with KRAS/BRAF wild-type rectal cancer, but the primary end point of improved CR was not met.

Oxaliplatin as a radiosensitiser for upper and lower gastrointestinal tract malignancies: what have we learned from a decade of translational research?

Some of the greatest advances in the treatment of solid malignancies have resulted from the combination of chemotherapy and radiotherapy treatments. This article comprehensively reviews the current clinical evidence for oxaliplatin-based chemo-radiotherapy that may improve local control and survival. In order to understand how clinical studies should be designed, the pre-clinical evidence for the use of oxaliplatin chemotherapy as a radiosensitising agent is appraised. Particular focus is placed on oxaliplatin's biological mechanisms of action, including cell cycle effects, the formation of DNA adducts and interstrand cross-links and the role of DNA repair proteins. At a clinical level, there is currently no evidence to suggest that oxaliplatin provides an additional benefit to concurrent chemo-radiation regimes that utilise fluoropyrimidines; we evaluate the reasons for this observation, the limitations of clinical trial design and the opportunities that currently exist to design clinical trials which are underpinned by an understanding of the basic biology.

Timing of surgery following preoperative therapy in rectal cancer: the need for a prospective randomized trial?

BACKGROUND

In rectal cancer, the standard of care after the completion of radiotherapy is surgery at 6 to 8 weeks. However, there is variation regarding the timing of surgery.

OBJECTIVE

This investigation aimed to audit the timing of surgery following radiotherapy and to compare perioperative morbidity and tumor downstaging in patients operated on, before and after the 6- to 8-week window.

DESIGN

A retrospective review of rectal cancers treated preoperatively in our cancer network over a 27-month period. The effect of "time till surgery" of 6 to 8 weeks, <6 weeks, and >8 weeks on T downstaging and nodal downstaging was calculated by univariate and multivariate logistic regression analyses.

SETTING

This study was conducted in an oncology tertiary referral center in the Southwest London Cancer Network.

PATIENTS

Patients receiving preoperative radiotherapy for primary locally advanced rectal cancer undergoing subsequent surgical resection were eligible.

MAIN OUTCOME MEASURES

The primary outcome measurement was time to surgery following the completion of (chemo) radiotherapy. Thirty-day perioperative morbidity and mortality and tumor and nodal downstaging were examined according to the timing of surgery.

LIMITATIONS

This study was limited by its nonrandomized retrospective design and the lack of standardization of preoperative chemotherapy.

RESULTS

Thirty-two (34%) patients underwent surgery at 6 to 8 weeks, 45 (47%) at >8 weeks, and 18 (19%) at <6 weeks after radiotherapy. Delay was attributed to scheduling in 87% of cases and to comorbidities in the remainder. T downstaging occurred in 6 (33.3%) patients in the <6 weeks group, in 12 (37.5%) in the 6 to 8 weeks group, and in 28 (62.2%) in >8 weeks group with no significant differences in perioperative morbidity. On multivariate analysis, T downstaging was significantly greater for the >8 weeks group (OR, 3.79; 95% CI: 1.11-12.99; P = .03). More patients were staged ypT0-T2, 19 of 45 (42%) in the >8 weeks group vs other groups, 14 of 50 (28%, P < .05).

CONCLUSIONS

Following radiotherapy, surgery frequently occurs at >8 weeks and is associated with increased downstaging. The consequences on survival and perioperative morbidity warrant further investigation.

Update on treatment advances in combined-modality therapy for anal and rectal carcinomas

Concurrent radiation therapy and chemotherapy is the primary treatment for patients with squamous cell tumors of the anal canal, and is also employed in the neoadjuvant setting for patients with stage II and III adenocarcinoma of the rectum. There is constant clinical study involving modifications of chemoradiotherapy regimens in an effort to maximize tumor responses while reducing normal tissue toxicity. This review will discuss established regimens as well as newer and novel treatment approaches to treatment of anal and rectal cancer.

Signet ring cell histology and non-circumferential tumors predict pathological complete response following neoadjuvant chemoradiation in rectal cancers

PURPOSE

Neoadjuvant chemoradiation followed by surgery is now the standard of care for patients with locally advanced rectal cancers. The aim of this study was to determine the rate of pathological complete response (pCR) following neoadjuvant treatment in patients with rectal cancers and identify the factors predicting the same.

METHODS

We conducted a retrospective analysis of patients with rectal cancers treated with neoadjuvant therapy followed by surgery at our institution from 1993 to 2008. Patients who achieved pCR were identified. Various patient, tumor, and treatment-related factors were studied for their influence on pCR by univariate and multivariate analyses. The influence of pCR on survival was also studied but was restricted to patients with a minimum follow-up of 5 years.

RESULTS

Between 1993 and 2008, 248 patients with rectal cancers received neoadjuvant therapy followed by surgery. Two hundred and twenty-seven patients received chemoradiation and 21 patients received only radiation. Pathological complete response was seen in 32 patients (12.9%). On multivariate analysis, the factors found to be independently predictive of pathological response were circumferential extent of the primary tumor (p = 0.016) and signet ring cell histology (p = 0.001). Among 116 patients with a minimum follow-up of 5 years, there was a trend towards increased overall survival (75% versus 54%) and reduced local recurrence (6.2% versus 12.3%) in the 16 patients who achieved a pCR compared to those who did not, even though the difference was not statistically significant.

CONCLUSIONS

The factors that predict a pCR after neoadjuvant treatment for rectal cancers are absence of circumferential involvement and signet ring cell histology. Pathological complete response may confer an insignificant survival advantage.

Adjuvant radiotherapy for rectal cancer: recent results, new questions

Many randomised studies have now well established the role of radiotherapy (RT) in rectal cancer: it decreases the rate of local relapse and improves survival for stage II and III. The benefit of RT remains even in case of total mesorectum excision. Preoperative strategy has a better tolerance and is more efficient than post-operative RT. Two schedules have been widely used: an hypofractionated (5 × 5 Gy) and a normofractionated (45-50 Gy by fractions of 1.8-2 Gy) schedule. Both have advantages and drawbacks. Patients with locally advanced tumours or low-lying cancer must benefit from a protracted schedule, which increases down staging and the number of sphincter-preserving surgery. Combined chemoradiotherapy with 5FU or capecitabine enhances local control without a clear benefit in overall survival or disease-free survival. Adjunction of oxaliplatin does not improve the pathological response rate significantly. Results with cetuximab are still disappointing. Bevacizumab seems to increase widely the radiation response, but more data are needed to confirm these preliminary results. With this modern approach, the rate of local relapse is lower than 10%; the main issue is now the occurrence of distant relapses in 25-30% of the patients. Neo-adjuvant chemotherapy (CT) seems the better way to address this issue, because post-operative CT could be done properly in only 50% of the patients. Large prospective trials using neo-adjuvant CT with or without targeted therapies must be designed taking distant relapses and overall survival as main end-points.

Rectal cancer radiotherapy: towards European consensus

BACKGROUND AND PURPOSE

During the first decade of the 21st century several important European randomized studies in rectal cancer have been published. In order to help shape clinical practice based on best scientific evidence, the International Conference on 'Multidisciplinary Rectal Cancer Treatment: Looking for an European Consensus' (EURECA-CC2) was organized. This article summarizes the consensus about imaging and radiotherapy of rectal cancer and gives an update until May 2010.

METHODS

Consensus was achieved using the Delphi method. Eight chapters were identified: epidemiology, diagnostics, pathology, surgery, radiotherapy and chemotherapy, treatment toxicity and quality of life, follow-up, and research questions. Each chapter was subdivided by topic, and a series of statements were developed. Each committee member commented and voted, sentence by sentence three times. Sentences which did not reach agreement after voting round # 2 were openly debated during the Conference in Perugia (Italy) December 2008. The Executive Committee scored percentage consensus based on three categories: "large consensus", "moderate consensus", "minimum consensus".

RESULTS

The total number of the voted sentences was 207. Of the 207, 86% achieved large consensus, 13% achieved moderate consensus, and only three (1%) resulted in minimum consensus. No statement was disagreed by more than 50% of members. All chapters were voted on by at least 75% of the members, and the majority was voted on by >85%. Considerable progress has been made in staging and treatment, including radiation treatment of rectal cancer.

CONCLUSIONS

This Consensus Conference represents an expertise opinion process that may help shape future programs, investigational protocols, and guidelines for staging and treatment of rectal cancer throughout Europe. In spite of substantial progress, many research challenges remain.

Adjuvant chemoradiotherapy of advanced resectable rectal cancer: results of a randomised trial comparing modulation of 5-fluorouracil with folinic acid or with interferon-α

Background:

Standard adjuvant chemoradiotherapy of rectal cancer still consists of 5-fluorouracil (5-FU) only. Its cytotoxicity is enhanced by folinic acid (FA) and interferon-α (INFα). In this trial, the effects of FA and IFNα on adjuvant 5-FU chemoradiotherapy in locally advanced rectal cancer were investigated.

Methods:

Patients with R₀-resected rectal cancer (UICC stage II and III) were stratified and randomised to a 12-month adjuvant chemoradiotherapy with 5-FU, 5-FU+FA, or 5-FU+IFNα. All patients received levamisol and local irradiation with 50.4 Gy.

Results:

Median follow-up was 4.9 years (n=796). Toxicities (WHO III+IV) were observed in 32, 28, and 58% of patients receiving 5-FU, 5-FU+FA, and 5-FU+IFNα, respectively. No differences between the groups were observed for local or distant recurrence. Five-year overall survival (OS) rates were 60.3% (95% confidence interval (CI): 54.3–65.8), 60.4% (54.4–65.8), and 59.9% (53.0–66.1) for 5-FU, 5-FU+FA, and 5-FU+IFNα, respectively. A subgroup analysis in stage II (pT3/4pN0) disease (n=271) revealed that the addition of FA tended to reduce the 5-year local recurrence (LR) rate by 55% and increase recurrence-free survival and OS rates by 12 and 13%, respectively, relative to 5-FU alone.

Conclusions:

Interferon-α cannot be recommended for adjuvant chemoradiotherapy of rectal cancer. In UICC stage II disease, the addition of FA tended to lower LR and increased survival. The addition of FA to 5-FU may be an effective option for adjuvant chemoradiotherapy of UICC stage II rectal cancer.