A multi-centre randomized controlled trial investigating Consolidation Chemotherapy with and without oxaliplatin in distal rectal cancer and Watch & Wait

BACKGROUND

Neoadjuvant chemoradiation(nCRT) has been considered the preferred initial treatment strategy for distal rectal cancer. Advantages of this approach include improved local control after radical surgery but also the opportunity for organ preserving strategies (Watch and Wait-WW). Consolidation chemotherapy(cCT) regimens using fluoropyrimidine-based with or without oxalipatin following nCRT have demonstrated to increase complete response and organ preservation rates among these patients. However, the benefit of adding oxaliplatin to cCT compared to fluoropirimidine alone regimens in terms of primary tumor response remains unclear. Since oxalipatin-treatment may be associated with considerable toxicity, it becomes imperative to understand the benefit of its incorporation into standard cCT regimens in terms of primary tumor response. The aim of the present trial is to compare the outcomes of 2 different cCT regimens following nCRT (fluoropyrimidine-alone versus fluoropyrimidine + oxaliplatin) for patients with distal rectal cancer.

METHODS

In this multi-centre study, patients with magnetic resonance-defined distal rectal tumors will be randomized on a 1:1 ratio to receive long-course chemoradiation (54 Gy) followed by cCT with fluoropyrimidine alone versus fluoropyrimidine + oxaliplatin. Magnetic resonance(MR) will be analyzed centrally prior to patient inclusion and randomization. mrT2-3N0-1 tumor located no more than 1 cm above the anorectal ring determined by sagittal views on MR will be eligible for the study. Tumor response will be assessed after 12 weeks from radiotherapy(RT) completion. Patients with clinical complete response (clinical, endoscopic and radiological) may be enrolled in an organ-preservation program(WW). The primary endpoint of this trial is decision to organ-preservation surveillance (WW) at 18 weeks from RT completion. Secondary endpoints are 3-year surgery-free survival, TME-free survival, distant metastases-free survival, local regrowth-free survival and colostomy-free survival.

DISCUSSION

Long-course nCRT with cCT is associated with improved complete response rates and may be a very attractive alternative to increase the chances for organ-preservation strategies. Fluoropyrimidine-based cCT with or without oxaliplatin has never been investigated in the setting of a randomized trial to compare clinical response rates and the possibility of organ-preservation. The outcomes of this study may significantly impact clinical practice of patients with distal rectal cancer interested in organ-preservation.

TRIAL REGISTRATION

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CLINICALTRIALS

gov NCT05000697; registered on August 11^th, 2021.

Maintenance therapy following an anti-EGFR-based induction regimen in metastatic colorectal cancer (mCRC): A network meta-analysis of clinical trials

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Background: A fluoropyrimidine with or without bevacizumab is often used in clinical practice as maintenance therapy after a first-line chemotherapy + bevacizumab induction in mCRC. However, the role of maintenance following an anti-EGFR-based induction and the optimal regimen are not well established. Methods: We searched PubMed and conferences’ proceedings for clinical trials assessing maintenance therapy after first-line treatment for RAS WT mCRC. Two independent reviewers excluded single-arm studies and retrospective reports from trials that were not designed to assess maintenance therapy. We used the method of Guyot et. al. to obtain the individual patient data, followed by a Cox procedure to derive the survival hazard ratios (HR) from studies that did not report that value. Safety analysis included grade 3-4 asthenia, neuropathy, neutropenia, rash, and diarrhea. We performed a random-effects bayesian network metanalysis using the package “GeMTC R Package” to compare all treatment strategies included (anti-EGFR, anti-EGFR + chemotherapy [CT], CT alone, and observation). The risk of bias was assessed according to the Cochrane Handbook for Systematic Reviews of Interventions. Results: The systematic review retrieved 145 studies from which 142 were excluded. Two additional studies were found in the Conferences’ Proceedings review. Consequently, 5 studies were included in this NMA. In terms of Progression-Free Survival (PFS), there was a benefit of anti-EGFR and anti-EGFR+CT versus CT alone (HR 0.63 [95%CrI 0.31-1.30] and 0.72 [95%CrI 0.41-1.30], respectively). The rank probability of anti-EGFR being the best option considering PFS was 61%. In terms of Overall Survival (OS), the benefit of anti-EGFR and anti-EGFR+CT versus CT alone was statistically weak (HR 0.92 [95%CrI 0.54-1.50] and 0.84 [95%CrI 0.57-1.20], respectively). The rank probability of anti-EGFR+CT be the best option in terms of OS was 51%. Comparing anti-EGFR versus anti-EGFR+CT resulted in no statistically significant difference. Anti-EGFR-containing regimens increased the rate of rash and diarrhea compared to CT alone (RR 11.23 and 1.23, respectively). The risk of bias was average low, except for the unclear risk of selection bias linked to unpublished studies. Conclusions: Anti-EGFR±CT maintenance therapy improves PFS and OS compared to CT alone or observation in RAS WT mCRC, with manageable safety profile.