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Background Neuroendocrine differentiation has been extensively associated with worse prognosis and to mechanisms of therapy resistance in several epithelial cancers. A high prevalence of neuroendocrine differentiation was recently described in V600EBRAF-mutated (BRAFmt) metastatic colorectal cancers (mCRCs) but no data are available about its prognostic impact in this setting. Methods We assessed synaptophysin immunohistochemical expression in a multi-institutional series of 159 BRAFmt mCRCs with matched clinical and pathological information. Tumours were dichotomized as synaptophysin high and low. Overall survival (OS) and progression-free survival (PFS) were evaluated by Kaplan–Meier and log-rank tests. Results Thirty-five tumours (22.0%) showed any level of positivity for synaptophysin, and 18 (11.3%) were characterized by positivity in at least 20% of tumour cells. Four cases resulted 100% synaptophysin positive. The histotype of synaptophysin-positive tumours (i.e. ≥20%) was not otherwise specified in 11 cases (61.1%) and mucinous adenocarcinoma in 4 cases (22.2%). Four cases were DNA mismatch repair deficient (22.2%) and 7 (38.9%) were characterized by a high number of tumour-infiltrating lymphocytes. At multivariate analysis, high synaptophysin expression was a negative independent prognostic factor for both PFS (HR = 2.00, 95% confidence interval [CI] 1.21–3.33, p = 0.006) and OS (HR = 2.27, 95% CI 1.35–3.85, p = 0.001). Conclusions Among BRAFmt mCRCs, synaptophysin-positive tumours are characterized by worse PFS and OS. Further studies should investigate the molecular mechanisms involved in the acquisition of the neuroendocrine phenotype to identify novel-targeted treatment strategies.

Background Alternating induction and maintenance phases is a common strategy in metastatic colorectal cancer (mCRC). Metronomic chemotherapy (metroCT) may represent a well-tolerated chemotherapy backbone for maximising bevacizumab effect during maintenance. The MOMA trial was designed to compare metroCT plus bevacizumab versus bevacizumab alone as maintenance following 4 months of induction with FOLFOXIRI plus bevacizumab. Patients and methods In this phase II study, patients with unresectable mCRC were randomised to receive up to 8 cycles of FOLFOXIRI plus bevacizumab, followed by bevacizumab (arm A) or the same regimen followed by bevacizumab plus metroCT (capecitabine 500 mg/three times per day and cyclophosphamide 50 mg/die, arm B) until disease progression. The primary end-point was progression-free survival (PFS). According to the Rubinstein and Korn's design, to detect a hazard ratio[HR] of 0.75 favouring arm B, with 1 sided-alpha and beta errors of 15% and 80%, 173 events and 222 patients were required. Results Between May 2012 and March 2015, 232 patients, mostly with RAS (65%) or BRAF (9%) mutant tumours, were randomised in 16 Italian centres. At a median follow-up of 47.8 months, 210 and 164 progression and death events were registered. The primary end-point was not met. Median PFS was 10.3 and 9.4 months in arm B and A, respectively (HR: 0.94 [70% confidence interval {CI}: 0.82–1.09], p = 0.680). No significant differences were reported in terms of overall survival (OS) (median OS arm B/A: 22.5/28 months; HR: 1.16 [95%CI: 0.99–1.37], p = 0.336). Response rate with FOLFOXIRI plus bevacizumab was 63% (arm B/A: 58%/68%). In the liver-limited subgroup, the secondary resection rate was 49% (arm B/A: 45%/55%). Conclusions The addition of metroCT to maintenance with bevacizumab does not significantly improve PFS of mCRC patients. The activity of FOLFOXIRI plus bevacizumab is confirmed in a population with high prevalence of RAS/BRAF mutations treated with a 4-months induction. Trial registration www.clinicaltrials.gov NCT02271464.

Background Despite the well-known negative prognostic value of the V600EBRAF mutation in patients with metastatic colorectal cancer (mCRC), its outcome is quite heterogeneous, and the basis for this prognostic heterogeneity should be better defined. Methods Two large retrospective series of V600EBRAF-mutated mCRC from 22 institutions served as an exploratory and validation set to develop a prognostic score. The model was internally and externally validated. Results A total of 395 V600EBRAF-mutated mCRCs were included in the exploratory set. Performance status, CA19.9, lactate dehydrogenase, neutrophil/lymphocyte ratio, grading and liver, lung and nodal involvement emerged as independent prognostic factors for overall survival (OS). Two different scoring systems were built: a ‘complete’ score (0–16) including all significant covariates and a ‘simplified’ score (0–9), based only on clinicopathological covariates, and excluding laboratory values. Adopting the complete score, proportions of patients with a low (0–4), intermediate (5–8) and high (9–16) score were 44.7%, 42.6% and 12.6%, respectively. The median OS was 29.6, 15.5 (hazard ratio [HR] for intermediate vs low risk: 2.16, 95% confidence interval [CI]: 1.44–3.22, p Conclusions These scoring systems are based on easy-to-collect data and defined specific subgroups with relevant differences in their life expectancy. These tools could be useful in clinical practice, would allow better stratification of patients in clinical trials and may be adopted for proper adjustments in exploratory translational analyses.

Background BRAF V600E mutation plays a negative prognostic role in metastatic colorectal cancer (mCRC), leading to a median Progression Free Survival (PFS) of 4–6 months with first-line conventional treatments. Our group recently reported in a retrospective exploratory analysis of a phase II trial that FOLFOXIRI (5-FU/LV+Oxaliplatin+Irinotecan) plus bevacizumab might allow to achieve remarkable results in terms of PFS and Overall Survival (OS) also in this poor-prognosis subgroup. The aim of this work was to prospectively validate our retrospective finding. Patients and methods This phase II trial was designed to detect an increase in 6 month-Progression Free Rate (6 m-PFR) from 45% to 80% in a population of BRAF mutant mCRC patients treated with first-line FOLFOXIRI plus bevacizumab. Secondary end-points were PFS, OS, response rate (RR) and the analysis of outcome parameters in the pooled population consisting of both retrospectively and prospectively included patients. This trial is registered with ClinicalTrials.gov, number NCT01437618 . Results Two-hundred-fourteen potentially eligible mCRC patients were screened for BRAF mutational status. Fifteen BRAF mutant patients (7%) were included in the validation cohort. At a median follow up of 25.7 months, 6 m-PFR was 73%. Median PFS and OS were 9.2 and 24.1 months, respectively. In the pooled population, at a median follow up of 40.4 months, 6 m-PFR was 84%. Median PFS and OS were 11.8 and 24.1 months, respectively. Overall RR and disease control rate were 72% and 88%, respectively. Conclusion Lacking randomised trials in this specific molecular subgroup, FOLFOXIRI plus bevacizumab might be a reasonable option for the first-line treatment of BRAF mutant mCRC patients.