VEGF信号通路及结直肠癌抗VEGF/VEGFR靶向治疗

化疗联合靶向药物是晚期结直肠癌的主要治疗手段。VEGF信号通路在结直肠癌发生发展中地位特殊,且针对VEGF信号通路的靶向药物临床应用广泛、疗效好。本文就VEGF信号通路及结直肠癌抗VEGF/VEGFR靶向药物作一综述。     

结直肠癌分子靶向治疗研究近况

结直肠癌分子靶向治疗已经逐步从临床研究走向临床常规应用,并不断被推向更前线的治疗中,而疗效相关标志研究也有所突破。文章对相关重要研究进行了综述,希望对临床合理化用药有所帮助。     

结直肠癌分子靶向治疗的现状及展望

0 引言结直肠癌是最常见的恶性肿瘤之一,其发病率位居肿瘤发病率的第三位.2008年全世界大约有1 000 000新诊断病例,大约有500 000例死于该疾病.结直肠癌的发病率随工业化和城市化的程度增高而增高,中国的结直肠癌发病率也呈现逐年上升的趋势.25％新诊断的结直肠癌病人伴有远处转移,40％～50％的初诊无转移病人在诊断治疗后也会出现远处转移.晚期转移性结直肠癌病人,如果不进行治疗,中位生存期仅为5～6月.     

贝伐单抗联合化疗一线治疗转移性结直肠癌的Meta分析

目的 评价贝伐单抗（bevacizumab,BEV)联合化疗一线治疗转移性结直肠癌（metastaticcolorectal cancer, mCRC）的有效性和安全性。方法 通过The Cochrane Library、PubMed、EMBASE和中国生物医学文献数据库（CBM）、中国期刊全文数据库（CNKI）、维普数据库（VIP）、万方数据库等检索有关BEV联合化疗一线治疗mCRC的随机对照试验（randomized control trial, RCT）;主要研究指标是无进展生存时间（progression free survival, PFS）和总生存时间（overall survival,OS）,次要研究指标包括有效率（objective response rate, ORR）和不良反应;采用相对危险度（relative risk, RR）和风险比（hazard ratios, HR）为效应量,各效应量以95%置信区间（95%CI）表示,Stata 11.0统计软件进行Meta分析。结果 共纳入9项RCT,共3 930例mCRC患者,Meta分析结果显示,与单纯化疗相比,贝伐单抗(bevacizumb, BEV)联合化疗可以降低疾病进展风险（HR=0.62,P<0.0001, 95%CI: 0.64~0.74）和疾病死亡风险（HR=0.84, P<0.001,95%CI: 0.73~0.95）,提高mCRC的ORR（RR=0.80, P<0.001,95%CI: 0.60~0.93）。亚组分析显示BEV联合双药方案可降低疾病进展风险（HR=0.68, P<0.001, 95%CI: 0.46~0.89）,但并没有降低疾病死亡风险（HR=0.85, P=0.068,95%CI:0.68~1.03）;BEV联合氟尿嘧啶类单药降低疾病进展风险（HR=0.56,P<0.001, 95%CI: 0.47~0.64）和疾病死亡风险（HR=0.83,P<0.001,95%CI:0.68~0.97）。在不良反应方面,B E V 联合化疗没有增加治疗相关死亡率（RR=0.97, P=0.91,95%CI:0.62~1.54）;增加BEV相关不良反应发生率。结论 BEV联合化疗一线治疗能提高mCRC患者PFS、OS和RR。BEV联合不同化疗方案所带来生存获益大小不同。虽然BEV相关不良反应增加,但是可控的。     

分子靶向药物给药模式对转移性结直肠癌患者生存的影响

目的 探讨两种不同类型靶向药物在不同给药模式下对转移性结直肠癌（mCRC）患者生存的影响。方法 回顾性分析135例接受过分子靶向治疗mCRC患者的临床病理特征、靶向治疗情况及随访资料,比较不同种类靶向药物及不同线数化疗联合靶向治疗对生存期（OS）的影响。结果 全组中接受抗EGFR单抗者、接受贝伐珠单抗者及接受抗EGFR单抗+贝伐珠单抗者的中位OS依次为20.7、24.4和41.6个月,接受两种靶向药物者比仅接受一种靶向药物者的中位OS有明显延长（P＜0.05）;一线化疗未联合靶向治疗者的中位OS为30.8个月,与一线化疗联合靶向治疗者的21.5个月相比,差异无统计学意义（P＞0.05）;三线及以上联合靶向治疗者的中位OS为37.0个月,高于三线前均联合靶向治疗者的137个月,差异有统计学意义（P＜0.05）;接受过三种化疗药物（伊立替康、奥沙利铂、氟尿嘧啶）及贝伐珠单抗和抗EGFR单抗两种靶向药物的患者中,三线及以上使用靶向者的中位OS为50.6个月,与三线前使用靶向者的41.6个月比较,差异无统计学意义（P＞0.05）。结论 接受过两类靶向药物治疗的mCRC患者比仅接受一类靶向药物者可能获得更好生存获益。患者使用靶向药物的时机并非越早越好,肿瘤生物学行为较好的患者更适合先化疗后靶向的治疗模式。     

VEGF抑制剂联合酪氨酸激酶抑制剂一线治疗EGFR突变晚期非小细胞肺癌的疗效和安全性

目的:探讨血管内皮生长因子(vascular endothelial growth factor,VEGF)抑制剂联合酪氨酸激酶抑制剂(tyrosine kinase inhibitors,TKI)一线治疗表皮生长因子受体(epidermal growth factor receptor,EGFR)突变晚期非小细胞肺癌...     

结直肠癌ＥＧＦＲ靶向治疗进展

近年来,一系列抗ＥＧＦＲ药物广泛用于结直肠癌的临床治疗,并取得了显著疗效。本文就晚期结直肠癌采用抗ＥＧＦＲ治疗的临床研究及疗效预测分子方面的新进展进行综述介绍。     

结直肠癌肝转移术前化疗与手术切除疗效的Meta分析

目的：探讨结直肠癌肝转移术前化疗能否提高患者的生存率。方法：计算机文献检索ISI Web ofKnowledge、Pubmed及中国期刊网,检索国内外自1990年1月至2010年12月间公开发表的有关结直肠癌肝转移治疗的文章。Meta分析比较术前化疗组与未接受术前化疗组术后生存率的差异。结果：术前化疗组与未接受术前化疗组相比较,1年生存率（OR=0.44,CI：0.17-1.13,P=0.07）、3年生存率（OR=1.02,CI：0.64-1.62,P=0.93）、5年生存率（OR=0.69,CI：0.42-1.14,P=0.16）均无统计学意义。结论：对于结直肠癌肝转移患者,术前化疗不能提高术后生存率。     

FOLFOXIRI方案一线治疗晚期结直肠癌的研究进展

结直肠癌是最常见的恶性肿瘤之一,晚期结直肠癌的主要治疗手段是全身药物治疗。近年来,两药联合化疗方案FOLFOX或FOLFIRI联合靶向药物抗VEGF单抗或抗EGFR单抗已成为晚期结直肠癌的标准一线治疗方案。氟尿嘧啶、奥沙利铂和伊立替康是结直肠癌的3种主要化疗药物。这3种药物的联合方案FOLFOXIRI在晚期结直肠癌的治疗中越来越重要。FOLFOXIRI较两药联合方案可以显著改善晚期结直肠癌患者的预后,但同时也明显增加了不良反应。如何在保证疗效的前提下降低不良反应是临床上亟需解决的问题。本文将对FOLFOXIRI方案一线治疗晚期结直肠癌的研究进展进行综述。      

替吉奥联合奥沙利铂一线治疗转移性结直肠癌有效性与安全性的Meta分析#br#

目的 评价替吉奥联合奥沙利铂（SOX）一线治疗转移性结直肠癌（mCRC）的有效性和安全性。方法 通过The Cochrane Library、PubMed、EMBASE和MEDLINE、中国知网（CNKI）、万方数据库等检索SOX方案一线治疗mCRC的多中心随机对照试验（RCT）,用Rev Man 53版软件进行Meta分析。结果 共纳入5项临床多中心RCT,合计1382例mCRC患者。Meta分析结果显示,与奥沙利铂联合其他氟尿嘧啶类化疗药物比较,SOX方案在无进展生存期（HR=0.90,95％CI：0.80～1.02,P=0.10）、总生存期（HR=1.14,95％CI：0.98～1.31,P=0.08）、客观缓解率（RR=1.12,95％CI：0.87～1.43,P=0.38）、疾病控制率（RR=104,95％CI：0.98～110,P=0.24）的差异均无统计学意义。3～4 级不良反应：SOX方案组的白细胞减少发生率低于奥沙利铂联合其他氟尿嘧啶类药物（P＜0.05）,而口腔黏膜反应、厌食、腹泻的发生率高于奥沙利铂联合其他氟尿嘧啶类药物（P＜0.05）,两种方案在中性粒细胞减少、血小板减少、贫血、恶心、呕吐、乏力不良反应的发生率方面差异均无统计学意义（P＞0.05）。结论 OX一线治疗晚期结直肠癌的疗效与奥沙利铂联合其他氟尿嘧啶类药物的疗效相似,不良反应不同,替吉奥有可能成为除卡培他滨外口服氟尿嘧啶类一线治疗晚期结直肠癌的另一种选择。     

Meta-analysis comparing the efficacy of anti-EGFR monoclonal antibody therapy between KRAS G13D and other KRAS mutant metastatic colorectal cancer tumours

BackgroundMetastatic colorectal cancer (mCRC) tumours harbouring a RAS mutation are associated with a lack of treatment benefit from anti-EGFR monoclonal antibodies (mAbs). However, observational evidence has led to speculation that mCRC patients with KRAS G13D mutant (MT) tumours may derive a benefit from treatment with anti-EGFR mAbs.MethodsWe conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate whether the efficacy of anti-EGFR mAbs for mCRC differs between tumours harbouring a KRAS G13D mutation (KRAS G13D) and KRAS mutations other than G13D (other KRAS MT).ResultsEight RCTs (n = 5967) met the inclusion criteria for assessment of both overall survival (OS) and progression-free survival (PFS). For other KRAS MT the hazard ratio for OS benefit with addition of anti-EGFR mAb therapy was 1.06 (95% confidence interval [CI]; 0.96, 1.17), compared to 1.08 (95% CI; 0.73, 1.60) for KRAS G13D [test for interaction p = 0.99]. In contrast, the hazard ratio for KRAS wild-type (WT) tumours was 0.85 (95% CI; 0.76, 0.95). Regarding PFS benefit with anti-EGFR mAbs, the hazard ratio was 1.07 (95% CI; 0.92, 1.26) for other KRAS MT, 0.96 (95% CI; 0.73, 1.27) for KRAS G13D, and 0.68 (95% CI; 0.54, 0.85) for KRAS WT. Again, the test for interaction (p = 0.46) demonstrated no significant difference in PFS benefit for anti-EGFR mAb therapy between KRAS G13D and other KRAS MT.ConclusionThis meta-analysis demonstrates no significant difference between KRAS G13D and other KRAS MT tumours in terms of treatment benefit from anti-EGFR mAbs for mCRC.     

贝伐珠单抗联合一线化疗晚期转移性结直肠癌的临床观察

目的：观察贝伐珠单抗联合一线化疗对晚期结直肠癌（metastatic colorectal cancer, mCRC）的疗效和毒副作用。方法30例经组织或细胞病理学证实的 mCRC 患者接受贝伐珠单抗与一线化疗药物联合治疗。贝伐珠单抗剂量为5 mg／kg 每2周重复,或7．5 mg／kg 每3周重复。一线化疗方案：18例联合 L-OHP 为主方案（FOLFOX 方案或者 CapeOx 方案）,12例联合 CPT-11为主方案（FOLFIRI方案）。评估疗效和不良反应并随访生存信息。结果30例中无 CR 患者,PR 15例（50．0％）,SD 10例（33．3％）,PD 5例（16．7％）;客观有效率50．0％,疾病控制率83．3％;中位无进展生存时间为10．809个月（95％CI：4．079～15．921）。贝伐珠单抗相关不良反应主要为高血压3例、鼻衄1例、蛋白尿1例。另有2例出现血液性毒性,考虑和化疗相关,接受 CPT-11方案者中4例出现迟发型腹泻。但上述副反应程度较轻,经对症处理后均可缓解,未影响治疗。结论贝伐珠单抗联合一线化疗对 mCRC 的疗效确切,不良反应发生率低、程度较轻,患者耐受性可,是mCRC一线治疗的理想选择。     

Reinduction of an Anti-EGFR-based First-line Regimen in Patients with RAS Wild-type Metastatic Colorectal Cancer Enrolled in the Valentino Study

BackgroundIn patients with RAS/BRAF wild-type metastatic colorectal cancer (mCRC), growing evidence supports anti-epidermal growth factor receptor (EGFR) retreatment, whereas little is known on the outcomes of anti-EGFR-based reinduction therapy during the upfront strategy.MethodsWe included patients enrolled in the Valentino study who had disease progression and received at least one dose of post-progression therapy. The Kaplan–Meier method and Cox proportional hazards regression were used for the survival analysis. When comparing the outcomes of anti-EGFR-based reinduction versus any second line, a propensity score–based matching was used.ResultsLiver-limited/single site of disease (P < .001 and P = .002), left-sidedness (P = .029), surgery of metastases (P = .003), early tumor shrinkage, and deeper responses (P = .018 and P = .036) were associated with the use of anti-EGFR-based reinduction versus any other second line. All patients treated with reinduction had an anti-EGFR-free interval of at least 3 months. In the propensity score–matched population, progression-free survival (PFS) was similar in the 2 treatment groups, the overall survival (OS) was significantly longer for patients treated with reinduction (P = .029), and the response rate was higher in patients treated with reinduction (P = .033). An oxaliplatin-free interval ≥12 months, left-sidedness, and molecular hyperselection beyond RAS/BRAF were associated with significantly better outcomes after anti-EGFR-based reinduction.ConclusionsReinduction strategies with anti-EGFR-based regimens are commonly used in clinical practice. Our data highlight the importance of clinical–molecular selection for re-treatments and the need for prospective strategy trials in selected populations.     

西妥昔单抗联合化疗在晚期结直肠癌一线治疗中的疗效观察

背景与目的:体内、外研究均表明,西妥昔单抗可以抑制表达表皮生长因子的人类肿瘤细胞的增殖并诱导其凋亡以及抑制肿瘤血管形成和转移,并己确立其在一线治疗晚期结直肠癌中的地位.本研究观察其在一线治疗晚期结直肠癌的疗效.方法:2007年2月-2007年12月厦门、泉州、漳州三地共五家医院对9例晚期结直肠癌患者应用西妥昔单抗联合化疗进行一线治疗.结果:一线治疗的9例患者中,完全缓解(CR)1例,部分缓解(PR)3例,稳定(SD)3例,进展(PD)2例,一线治疗的有效率(CR PR)44.4%.疾病控制率(CR PR SD)66.6%.结论:晚期结直肠癌一线治疗使用西妥昔单抗联合化疗有较好的疗效,不良反应可耐受.     

Systematic review of pharmacogenetic testing for predicting clinical benefit to anti-EGFR therapy in metastatic colorectal cancer

Pharmacogenetic testing can help identify patients with metastatic colorectal cancer more likely to respond to anti-EGFR therapy. We systematically reviewed the benefits and harms of EGFR-related pharmacogenetic testing of molecular targets downstream to KRAS in the treatment of metastatic colorectal cancer. We searched five electronic databases from January 2000 through November 2010, and conducted separate grey literature and conference abstracts searches. Two reviewers independently assessed all articles for relevance and quality. We identified 27 studies, primarily fair- to marginal-quality, small retrospective, and single-arm cohort studies with significant overlap in patient populations. We identified seven studies that studied BRAF in independent patient populations, one that studied NRAS, four that studied PIK3CA, eight that studied PTEN expression, and five that studied AKT expression. The best evidence for BRAF, NRAS, and PIK3CA comes from the largest retrospective study (n=649) of chemorefractory patients from seven European countries. In this study, BRAF mutation was present in 6.5% of KRAS wild-type tumors. Only 8.3% of persons with BRAF mutations, compared to 38% of persons without BRAF mutations (p=0.0012), responded to chemotherapy with cetuximab. Clinical sensitivity and the false positive fraction (1- specificity) were estimated at 9.8% (95% CI 6.3, 14.5) and 1.6% (95% CI 0.2, 5.6), respectively. BRAF mutation was also associated with worse median progression-free survival (absolute difference 18 weeks, p<0.0001), and overall survival (absolute difference 28 weeks, p<0.0001). In the only study comparing outcomes in persons who did (n=227) and did not (n=332) receive cetuximab with combination chemotherapy, those with BRAF mutation had worse survival outcomes regardless of whether or not they received cetuximab. Although NRAS and PIK3CA exon 20 mutations were also associated with worse outcomes compared to persons without these mutations, evidence is based on a small number of identified mutations. Evidence for protein expression of PTEN and AKT is more sparse and limited by variable methods for assessing protein expression. Low-quality evidence addressing clinical validity of pharmacogenetic testing in metastatic colorectal cancer patients suggests that BRAF mutations are associated with poorer treatment response and survival outcomes, although this association may be independent of treatment with EGFR inhibitors.     

西妥昔单抗联合化疗一线治疗KRAS/RAS野生型转移性结直肠癌的疗效及预后因素分析

目的探索影响西妥昔单抗联合化疗一线治疗KRAS/RAS野生型转移性结直肠癌的疗效和预后因素。方法回顾性分析155例接受西妥昔单抗联合化疗作为一线治疗方案的KRAS/RAS野生型转移性结直肠癌患者的病历资料,采用χ2检验或Fisher检验评估客观缓解率(ORR);采用Cox比例风险模型探讨KRAS/RAS野生型转移性结直肠癌患者预后的影响因素。结果西妥昔单抗联合化疗的中位治疗时间为18(6～26)周,一线治疗的ORR为60.1%,疾病控制率为92.2%。整体人群的中位随访时间为25.3(3.8～89.7)个月。一线治疗中位无进展生存期(PFS)为8.9个月(95%CI:7.9～9.9),中位总生存期(OS)为28.7个月(95%CI:23.6～33.8)。单因素分析结果显示:有腹膜转移、BRAF突变型、原发肿瘤未切除、转移灶未切除的KRAS/RAS野生型转移性结直肠癌患者的中位PFS短于无腹膜转移、BRAF野生型、原发肿瘤已切除、转移灶已切除的患者(P﹤0.05);原发肿瘤部位在右半结肠、有腹膜转移、BRAF突变型、原发肿瘤未切除、转移灶未切除的KRAS/RAS野生型转移性结直肠癌患者的中位OS短于原发肿瘤部位在左半结直肠、无腹膜转移、BRAF野生型、原发肿瘤已切除、转移灶已切除的患者(P﹤0.05)。多因素分析结果显示:BRAF突变型、原发肿瘤未切除是KRAS/RAS野生型转移性结直肠癌患者PFS的独立危险因素;有腹膜转移、BRAF突变型、转移灶未切除是KRAS/RAS野生型转移性结直肠癌患者OS的独立危险因素(P﹤0.05)。结论 BRAF突变和腹膜转移可能是西妥昔单抗联合化疗一线治疗KRAS/RAS野生型转移性结直肠癌预后的独立危险因素。原发肿瘤部位与OS相关,转移灶切除患者的PFS和OS均延长。     

A retrospective observational study on the safety and efficacy of first-line treatment with bevacizumab combined with FOLFIRI in metastatic colorectal cancer

Background:

Combination of bevacizumab and FOLFIRI has currently become one of the standard therapeutic regimens. However, published information is still limited. The objective of the present retrospective observational study is to analyse the response and toxicity of first-line treatment with FOLFIRI+bevacizumab in patients with metastatic colorectal cancer (mCRC).

Methods:

Data were collected from patients from nine Spanish sites diagnosed with mCRC, ECOG⩽2, whose first treatment for advanced disease was at least three cycles of FOLFIRI+bevacizumab.

Results:

A total of 95 patients were enrolled into the study: 64.2% males, median age of 59 years (53.2–67.1 years), ECOG=0–1 in 96.9% of patients. The main site of primary tumour was the colon (69.7%), and most metastases occurred in the liver (71.6%). Clinical benefit was detected in 67.4% (57.0–76.6; 95% confidence interval (CI)), with 8.4% of CR and 42.1% of PR. Median TTP was 10.6 months (10.0–11.3; 95% CI), PFS was 10.6 months (9.8–11.3; 95% CI), and OS was 20.7 months (17.1–24.2; 95% CI). Main grade I–II toxicities included haematological toxicity (35.8%), diarrhea (27.3%), mucositis (25.3%), asthenia (19.0%), haemorrhages (11.6%), and emesis (10.6%). Toxicities reaching grades III–IV were haematological toxicity (9.5%), diarrhea (8.5%), mucositis (5.3%), hepatic toxicity (2.1%), asthenia (2.1%), proteinuria (1.1%), emesis (1.1%), pain (1.1%), and colics (1.1%).

Conclusion:

Results of this study support the beneficial effect of adding bevacizumab to FOLFIRI regimen in terms of efficacy and show a favourable tolerability profile.     

Mucinous Histology Is Associated with Resistance to Anti-EGFR Therapy in Patients with Left-Sided RAS/BRAF Wild-Type Metastatic Colorectal Cancer

BackgroundLimited studies have suggested that mucinous histology is associated an attenuated response to anti-epidermal growth factor receptor (EGFR) therapy.MethodsWe conducted a single-institution, retrospective study to review the anti-EGFR response and the molecular profile of patients with left-sided microsatellite stable RAS/BRAF wild-type mucinous metastatic colorectal cancer.ResultsIn comparison to nonmucinous population (n = 98), mucinous histology (n = 20) was associated with a younger age (48 vs 54, P = .02), wild-type APC (80% vs 15.3%, P < .0001), and wild-type TP53 (40% vs 8.2%, P = .001). Guanine nucleotide binding protein, alpha stimulating (GNAS) mutations were exclusively found in mucinous tumors (20% vs 0, P < .0001). Genomic alterations associated with resistance to anti-EGFR therapy, such as ERBB2 amplification, PIK3CA mutation, MAP2K1 mutation, and KRAS amplification, were identified in patients with left-sided RAS/BRAF wild-type mucinous metastatic colorectal cancer. Mucinous histology was not associated with a worse outcome than non-mucinous histology (34.3 vs 42.2 months, P = .85). However, patients with left-sided RAS/BARF wild-type mucinous colorectal cancer treated with first-line anti-EGFR therapy had significantly worse progression-free survival (4 vs 6.5 months, hazard ratio [HR] = 5.3, 95% confidence interval [CI] 1.3-21.7, P = .01) than patients treated with the first-line vascular endothelial growth factor A antibody, bevacizumab. Anti-EGFR therapy was associated with limited responses and a short PFS across all lines of therapy in 12 patients with left-sided RAS/BRAF wild-type mucinous colorectal cancer.ConclusionsMucinous histology is associated with diminished benefits from anti-EGFR therapy in patients with left-sided RAS/BRAF wild-type colorectal cancer. These patients should be considered for bevacizumab-based therapy in the first- and second-line settings.     

A multicenter phase II study of the combination of oxaliplatin, irinotecan and capecitabine in the first-line treatment of metastatic colorectal cancer

The triple drug combination consisting of irinotecan, oxaliplatin and 5-fluorouracil (FOLFOXIRI) has demonstrated higher activity and efficacy compared to the doublet FOLFIRI. 5-Fluorouracil could be substituted in FOLFOXIRI regimen by capecitabine, an oral fluoropyrimidine with similar efficacy. Recently, a dose-finding trial has demonstrated the feasibility of the combination of irinotecan, oxaliplatin and capecitabine (XELOXIRI) and established their recommended doses. The aim of this study was to evaluate the activity of XELOXIRI. A total of 36 patients with unresectable metastatic colorectal cancer received irinotecan 165 mg m⁻² and oxaliplatin 85 mg m⁻² on day 1 plus capecitabine 2000 mg m⁻² per day orally in two doses from day 1 to day 7, every 2 weeks. Grade 3–4 toxicities were infrequent, expect for neutropenia and diarrhoea, which were each observed in 30% of patients. Two complete and twenty-two partial responses were obtained, corresponding to an overall response rate of 67% (95% CI 51.4–82%). After a median follow-up of 17.7 months, the median progression-free and overall survival were 10.1 and 17.9 months, respectively.The substitution of 5-fluorouracil with capecitabine, in combination with irinotecan and oxaliplatin, is feasible and does not impair the activity of the regimen. However, the XELOXIRI combination is associated with a high incidence of diarrhoea and, therefore, should be considered as a not preferable alternative to FOLFOXIRI.     

Meta-analysis of BRAF mutation as a predictive biomarker of benefit from anti-EGFR monoclonal antibody therapy for RAS wild-type metastatic colorectal cancer

Background:

Metastatic colorectal cancer (mCRC) that harbours a BRAF V600E mutation (BRAF MT) is associated with poorer outcomes. However, whether this mutation is predictive of treatment benefit from anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) is uncertain.

Methods:

We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) published up to July 2014 that evaluated the effect of BRAF MT on the treatment benefit from anti-EGFR mAbs for mCRC.

Results:

Seven RCTs met the inclusion criteria for assessment of overall survival (OS), whereas eight RCTs met the inclusion criteria for assessment of progression-free survival (PFS). For RAS WT/BRAF MT tumours, the hazard ratio for OS benefit with anti-EGFR mAbs was 0.97 (95% CI; 0.67–1.41), whereas the hazard ratio was 0.81 (95% CI; 0.70–0.95) for RAS WT/BRAF WT tumours. However, the test of interaction (P=0.43) was not statistically significant, highlighting that the observed differences in the effect of anti-EGFR mAbs on OS according to the BRAF mutation status may be due to chance alone. Regarding PFS benefit with anti-EGFR mAbs, the hazard ratio was 0.86 (95% CI; 0.61–1.21) for RAS WT/BRAF MT tumours as compared with 0.62 (95% CI; 0.50–0.77) for RAS WT/BRAF WT tumours (test of interaction, P=0.07).

Interpretation:

This meta-analysis demonstrates that there is insufficient evidence to definitively state that RAS WT/BRAF MT individuals attain a different treatment benefit from anti-EGFR mAbs for mCRC compared with RAS WT/BRAF WT individuals. As such, there are insufficient data to justify the exclusion of anti-EGFR mAb therapy for patients with RAS WT/BRAF MT mCRC.