Histological changes secondary to use of anti-angiogenic therapy after interruption of vasa vasorum flow in the descending aorta: results in a porcine model / Alterações histológicas secundárias à interrupção dos vasa vasorum na aorta descendente com o uso de terapia antiangiogênica: resultados em modelo suíno

Background Anti-angiogenic regulators may have therapeutic implications for onset and progression of atherosclerosis. Objectives To demonstrate histological changes secondary to the use of bevacizumab in the aorta of pigs after interruption of flow in the vasa vasorum. Methods Twelve pigs were divided into two groups. The intercostal arteries of the descending aorta were dissected and ligated and wrapped with a polyvinyl chloride membrane. The treatment group received an intravenous dose of bevacizumab. After 15 days, the animals were euthanized and the aorta removed. Histological slides were prepared for control and treatment groups and for non-manipulated areas and analyzed for degree of angiogenesis, injury, inflammation, and intimal thickening. Data were expressed as mean (SD) of scores and groups were compared using the Mann-Whitney test. The Poisson distribution was used to calculate 95% confidence intervals for mean scores, in order to determine effect statistics. Results Bevacizumab had adverse effects on all treated pigs. The analysis using a Scale of Magnitudes for Effect Statistics showed a trend toward a decrease in angiogenesis [0.58 (1.79/-0.63)] and injury [0.55 (1.76/-0.66)] and an increase in inflammation [0.67 (1.89/-0.55)] with threshold moderate effects. There was no difference in intimal thickening [0 (1.19/-1.19)]. Conclusions The medication exhibited a trend toward reduced angiogenesis and injury, but no reduction in the inflammatory process or intimal thickening of the aortic wall. These findings are in disagreement with studies that correlate neovascularization with increased migration of inflammatory cells. Bevacizumab exhibited toxicity in the porcine model

Agentes antiangiogênicos podem ter implicações terapêuticas na progressão e manifestação da aterosclerose. Objetivos Demonstrar a alteração histológica secundária ao uso de bevacizumabe na aorta descendente de suínos submetida à interrupção dos vasa vasorum. Métodos Em doze suínos, divididos em dois grupos, foi realizada dissecção da aorta torácica, além de ligadura das artérias intercostais e proteção com polivinil. O grupo tratamento recebeu dose endovenosa de bevacizumabe. Após 15 dias, os animais foram sacrificados para retirada da artéria e preparo das lâminas histológicas dos grupos tratamento, controle e áreas não manipuladas para análise quanto aos graus de angiogênese, injúria, inflamação e espessamento intimal. A análise estatística foi conduzida através da média e do desvio padrão dos escores. As comparações entre os grupos foram realizadas pelo teste de Mann-Whitney. A distribuição de Poisson calculou os intervalos de confiança de 95% para as médias, a fim de determinar o efeito estatístico. Resultados O bevacizumabe causou efeitos adversos em todos os suínos tratados. As variáveis analisadas através da Escala de Magnitude para Efeito Estatístico demonstraram tendência de redução da angiogênese [0,58 (1,79/-0,63)] e da injúria [0,55 (1,76/-0,66)] e aumento da inflamação [0,67 (1,89/-0,55)] no limite do moderado. Não ocorreu diferença no espessamento intimal [0 (1,19/-1,19)]. Conclusões A medicação utilizada mostrou tendência de redução da angiogênese e da injúria, mas não reduziu o processo inflamatório ou o espessamento intimal da parede arterial. Esses achados contrariam estudos que correlacionam a neovascularização com o aumento da migração de células inflamatórias. O bevacizumabe mostrou toxicidade no modelo suíno

Bevacizumab intravítreo como tratamiento de maculopatías miópicas neovasculares / Intravitreal bevacizumab for neovascular myopic maculopathy

INTRODUCCIÓN: La miopía patológica es una causa importante de pérdida de visión irreversible y es la cuarta a novena causa más frecuente de ceguera en el mundo. Es también conocida como miopía alta, degenerativa o maligna; condición en la que los individuos tienen una longitud axial superior a 25,5 - 26,5mm, y/o un error de refracción de por lo menos -5.0 dioptrías, acompañado por cambios patológicos. La neovascularización coroidea (NVC) asociada a miopía patológica puede resultar en la pérdida significativa de la visión y/o la ceguera. La NVC suele ser subfoveal y es una importante complicación, desarrollándose en aproximadamente 5-10% de ojos con miopía patológica. De manera similar que en otras enfermedades maculares asociadas a NVC, se ha encontrado un aumento del nivel del factor de crecimiento de endotelial (VEGF) en NVC miópicas, y por lo tanto, la terapia anti-VEGF sería útil. Desde la introducción en oftalmología de agentes anti factor de crecimiento de endotelial (anti-VEGF), el tratamiento anti-angiogénico con antiVEGF intravítreo se ha convertido en el tratamiento de primera línea para la NVC miópica. El bevacizumab es un anticuerpo monoclonal humano, anti factor de crecimiento endotelial (anti-VEGF), que inhibe la proliferación de nuevas células endoteliales produciendo un bloqueo de la fosforilación de las uniones estrechas (tight junctions) de las mismas. Este mecanismo produciría una mejoría anatómica-funcional en los pacientes e impediría una de las complicaciones más importantes de esta patología como lo es la neovascularización. OBJETIVO: Evaluar la eficacia de bevacizumab intravítreo (Avastin ®™) como tratamiento de la neovascularización coroidea (NVC) en miopías patológicas. PACIENTES Y MÉTODOS: Se evaluaron retrospectivamente 22 pacientes con diagnóstico de maculopatía miópica neovascular tratados mediante inyección intravítrea de bevacizumab, con un seguimiento mínimo de 12 meses. La agudeza visual se evaluó mediante tabla de Snellen y se convirtió en unidades LogMAR. El espesor macular se evaluó mediante tomografía de coherencia óptica (OCT). Las variables cuantitativas se analizaron mediante medidas de tendencia central, dispersión y forma. Los cambios en la agudeza visual se calcularon utilizando la prueba de Wilcoxon para variables apareadas y con la prueba de Mann Whitney para comparar variables independientes. Las diferencias entre variables continuas con distribución normal y de muestras independientes fueron calculadas mediante la prueba T de Student. RESULTADO: Se estudiaron 22 pacientes con diagnóstico de maculopatía miópica neovascular, cuya edad promedio fue de 59,68 (de 11,75; rango 34,00 ­ 85,00), de los cuales 7 (31,8%) fueron hombres y 15 (68,2%) fueron mujeres. El tiempo de seguimiento fue de 12 meses. El tiempo promedio transcurrido entre el comienzo de los síntomas y el inicio del tratamiento fue 38,68 (de 34,63) días. El 68,2% (15) de los pacientes consultaron por disminución brusca de la agudeza visual del ojo afectado y 31,8% (7) consultaron por metamorfopsias. Todos los pacientes presentaron miopía patológica (> 5.0 dioptrías). La cantidad total de inyecciones durante el seguimiento tuvo una media de 4,27 (DE 1.86; Rango 2,00 ­ 9,00), con un máximo de 9 inyecciones y un mínimo de 2 inyecciones. Durante los primeros 6 meses se realizaron la mayor parte de las inyecciones con una media de 3,36 (DE 1,22; Rango 1,00 ­ 6,00). La mediana de la AV al momento del tratamiento fue de 1,00 (P25-75=0,40-1,00). Al analizar la totalidad de los pacientes se encontró que existe una diferencia significativa al comparar las agudezas visuales previas al tratamiento y a los 12 meses de tratamiento (p=<0.0001). La mejoría franca de la AV se observó entre el primer mes (mediana= 1.00 RIQ= 0,6) y los 3 meses de tratamiento (mediana= 0,60 RIQ= 0,6) (p= 0,0002), mientras que no hubo diferencias significativas en la variación de la AV más allá de los 3 meses de seguimiento (p= 0,09). Al estudiar los espesores maculares antes del tratamiento, encontramos una mediana de 290 (RIQ=105); mientras que a los 12 meses de seguimiento fue de 269,50 (RIQ= 91). Teniendo en cuenta el total de los pacientes estudiados, no hubo diferencias significativas en el análisis del espesor macular medido por OCT antes y después del tratamiento (p=0,8812). CONCLUSIONES: El bevacizumab fue eficaz en el tratamiento de la maculopatía miópica, si bien no se encontraron diferencias significativas en la variación del espesor macular. En nuestra serie no hubo complicaciones oculares ni sistémicas vinculadas al tratamiento. (AU)

BACKGROUND: Pathological myopia is observed in about 2% of the general population. Submacular choroidal neovascularization is a leading cause of severe visual loss and blindness in eyes with pathological myopia, affecting 4-11% of those eyes. PURPOSE: Our aim is to evaluate the efficacy and safety of intravitreal bevacizumab in the treatment of neovascular myopic maculopathy (NMM). PATIENTS AND METHODS: 22 nonpreviously treated eyes of 22 consecutive patients with NMM. were reated with monthly intravitreal injections of bevacizumab and followed up for 12 months. Changes in BCVA and central macular thickness were evaluated at 12 months of follow-up. Snellen best-corrected visual acuity (BCVA) was converted into LogMAR units. Mean central macular thickness was obtained by means of spectral domain optical coherence tomography (SP-OCT). Quantitative variables were analyzed with central tendency, dispersion and shape. Changes in BCVA were calculated with Wilcoxon test in paired variables. Mann Whitney test was used to compare independent variables. Differences between continuous variables with normal distribution and independent samples were calculated with the Student T test. Main outcome measures: Changes in BCVA and central macular thickness at12 months of follow-up. RESULTS: Mean age was 54.45 (SD 12.30; r= 28.00 ­ 79.00); 7 patients (31.8%) were male and 15 (68.2%) female. Mean spherical equivalent refractive error was -10.89±4.13 (r= 7.00 to -21,00) Mean time elapsed between initial symptoms and the beginning of treatment was 38.68 (SD34.63) days. Patients received a mean of 4.27 (SD 1.86; r=2.00 to 9.00) injections. Most injections were performed during the first 6 months of treatment (mean 3.36 months; SD 1.22; r=1.00 to 6.00). Median BCVA at baseline was 1.00 (P25-75=0.40-1.00) and at 12 months 0.45 (P25-75=0.30- 0.70) (p<0.0001). Significant visual improvement was observed between the first (median=1.00, IQR= 0.6) and the third month of treatment (median=0.60, IQR=0.6) (p=0.0002), with no further significant improvement (p=0.09). No ocular or systemic side effects attributable to treatment were observed. When comparing patients 55 years old or younger with those older, and between both genders, all individuals improved, although not significantly (Mann Whitney for age P=0.1765; gender P=3454). No significant improvement in macular thickness was observed (pretreatment median thickness 290 microns, IQR=105; month 12 post-treatment median thickness 269.5 microns, IQR=91) (P=0.8812). CONCLUSIONS: Bevacizumab was effective and safe in our series of myopic patients with neovascular maculopathy, and visual gain remained stable during follow-up. (AU)

Bevacizumab intravítreo en el tratamiento de las oclusiones venosas de la retina / Bevacizumab in the treatment of macular edema complicating retinal vein occlusions

INTRODUCCIÓN: Dentro de las vasculopatías retinianas, las oclusiones venosas de la retina (OVR) representan la segunda causa más frecuente de pérdida de visión luego de la retinopatía diabética. Se han descripto dos tipos diferentes de OVR: la oclusión de vena central de la retina (OVCR), y la oclusión de rama venosa retinal (ORVR). De acuerdo al compromiso oclusivo del lecho capilar de la retina, se las clasifica en isquémicas (o no perfundidas), y no isquémicas (perfundidas), presentando una patogénesis, diagnóstico, pronóstico y tratamiento diferente. Se ha demostrado que los niveles de factor de crecimiento vascular endotelial (VEGF) aumentan significativamente en las oclusiones venosas retinianas, lo que tiene como consecuencia una disfunción de la barrera hematorretinal y el aumento de la permeabilidad vascular, con el consecuente edema macular. La inyección intravítrea de bevacizumab, un anticuerpo monoclonal recombinante que actúa en forma directa contra cualquier forma activa de VEGF, ha demostrado ser efectiva para reducir el espesor macular y mejorar la agudeza visual en el tratamiento de OVR. OBJETIVO: Evaluar los cambios en la agudeza visual y en los espesores maculares de pacientes con oclusiones venosas retinianas tratados con inyecciones intravítreas de bevacizumab. Pacientes y métodos: Se evaluaron retrospectivamente 39 pacientes con diagnóstico de oclusión venosa retiniana (OVR) complicada de edema macular y tratados mediante inyección intravítrea de 1,25 mg/0,05 ml bevacizumab (Avastin®, Roche Diagnostic GmbH, Manheim, Alemania), con un seguimiento mínimo de 18 meses. La agudeza visual se evaluó mediante tabla de Snellen y se convirtió en unidades LogMAR. El espesor macular se evaluó mediante tomografía de coherencia óptica (OCT). Según la presentación clínica se las clasificó en: 1. Oclusión de rama (ORVR), incluyendo las oclusiones hemisféricas y 2. Oclusión de vena central (OVCR), incluyendo oclusión venosa hemicentral. A su vez, mediante angiografía fluoresceínica se las clasificó en oclusiones predominántemente isquémicas, y predominántemente no isquémicas. Las variables cuantitativas se analizaron mediante medidas de tendencia central, dispersión y forma. Los cambios en la agudeza visual se calcularon utilizando la prueba de Wilcoxon. Las diferencias entre variables continuas fueron calculadas mediante la prueba T de Student para variables paramétricas, y Mann Whitney para variables no paramétricas. RESULTADOS: La edad promedio fue de 66,8 años (DE: 13,65; rango= 31-92 años). El 55% de los casos estudiados fueron OVCR y el 37,5% ORVR. La media del total de inyecciones durante los 18 meses de seguimiento fue de 4,11±1,61 (rango= 1 a 6). La terapia con láser de rescate se realizó en 10 (25%) pacientes. Todos los pacientes que debieron ser tratados con láser tuvieron una AV inferior a 1 décima al final del seguimiento. La agudeza visual promedio al inicio del tratamiento fue de 1,092 con una desviación estándar (DE) de 0,36, con un rango de 0,10 y 1,60. Tras el inicio del tratamiento, todos los grupos de pacientes logran un incremento significativo en la AV (P= <0,0001). A los 18 meses de tratamiento la agudeza visual promedio fue de 0,739 con una DE de 0,45 con un rango de entre 0,00 y 1,50. La agudeza visual media de los pacientes con OVCR antes del tratamiento fue de 1,09 (DE: 0,35; rango= máxima 0,50 y mínima 1,60), y a los 18 meses de tratamiento de 0,87 (DE: 0,73; rango= 0,20 a 1,50). En cambio, los pacientes con ORVR antes del tratamiento presentaron una media de 1,10 (DE: 0,31; rango= máxima de 0,40 y mínima de 1,6), y luego del tratamiento una media de 0,53 (DE: 0,38; rango= máxima 0,1 y mínima 1,2). El 54,5% de los casos fue de predominio isquémico o mixtos, y el 43,5% fue a predominio edematosos al inicio del tratamiento. La agudeza visual media de los pacientes con tipo edematoso fue de 0,93 (DE: 0,34; rango= máxima 0,10 y mínima 1,40), mientras que los pacientes con patología isquémica presentaron una media de 1,25 (DE: 0,32; rango= máxima de 0,40 y mínima de 1,6). Ambos grupos respondieron en forma significativa al tratamiento (p< 0.05). Sin embargo, los pacientes con predominio edematoso lograron una mejoría mayor que aquellos con predominio isquémico. (P=0.0054) La agudeza visual media de los pacientes con predominio edematoso a los 18 meses del tratamiento fue de 0,50 (DE: 0,44; rango= máxima 0,0 y mínima 1,40), mientras que los pacientes con predominio isquémico presentaron una media de 0,97 (DE: 0,35; rango= máxima 0,20 y mínima 1,4). La media de los espesores maculares previo al inicio del tratamiento fue de 654.19 ± 272.05 micras (rango= 215 a 1497 micras), mientras que la media luego del tratamiento fue de 449 ± 247,62 micras (rango= 140 a 1005 micras) (p=0,0009). No hubo efectos colaterales ni complicaciones locales ni sistémicas atribuibles a la inyección de bevacizumab durante el seguimiento. CONCLUSIÓN: El bevacizumab fue eficaz en el tratamiento del edema macular secundario a OVR. La respuesta terapéutica fue mayor en las ORVR. En nuestra serie no hubo complicaciones oculares ni sistémicas vinculadas al tratamiento. (AU)

INTRODUCTION: Within the retinal vascular disease,retinal venous occlusion (RVO) represents the second most common cause of vision loss after diabetic retinopathy. In turn, it is estimated that the RVO affects approximately 1.6% of people worldwide. It has been described two different types of RVO: the central retinal vein occlusion (CRVO), which includes the hemicentral retinal vein occlusion (HCRVO), and the branch retinal vein occlusion (BRVO), which includes Major BRVO (occlusion of a retinal vein that drains one of the quadrants or more), Minor BRVO (occlusion of a retinal vein that drains less than a quadrant) and Hemispheric retinal vein occlusions (half or more of the retina). According to the occlusive pattern of the retinal capillary bed, this disease is classified as ischemic (or non perfused); when the areas of noncapillary perfusion, seen under fluorescein angiography, have an extension of more than 10 disc diameters; and non-ischemic (o perfused), presenting a pathogenesis, diagnosis, prognosis and different treatment. Non-ischemic form is generally more benign, with a less dramatic visual impairment, a greater chance of spontaneous recovery, a better treatment response, and generally has no risk of neovascularization. Instead; ischemic form is much more severe, causing a more dramatic visual acuity decline, with little chance of clinical improvement, an increased risk of blindness and an increased risk of neovascularization. Although the physiopathogenesis of OVR is not accurately known, it is suggested that the thickening and stiffness of arteries and arterioles caused by arteriosclerosis leads to compression of the retinal veins at the sites where adventitia is shared with arteries (in its intraneural route to the optic nerve and the arteriovenous crossings), leading eventually to a turbulent blood flow, damage to endothelial cells, thrombus formation and eventual vein occlusion. This theory is supported by studies showing pathological structural changes in veins and arteries of patients with VO. Moreover, other factors related to venous deregulation, such as inadequate vasoconstriction and increased vascular permeability, could also play an important role in the retinal venous occlusive phenomena. In some patients, especially young people and adults under 50 years old, inflammatory disorders and hypercoagulable states may contribute to the hysiopathogenesis of the RVO. It has been shown that the presence of vascular endothelial growth factor (VEGF) increased significantly the chances to develop retinal vein occlusions. The result is a blood­retinal barrier dysfunction and an increased vascular permeability, with consequent macular edema. It has also been reported that VEGF plays an important role in the pathogenesis of macular edema in both ORV and CRVO.10 While there is insufficient level 1 evidence to support OVR treatment, multiple therapeutic possibilities have been described, such as anticoagulation, intravitreal fibrinolysis, hemodilution, laser photocoagulation, laser-induced anastomosis, radial optical neurotomy, adventiciotomía, intravitreal injection of triamcinolone acetonide, intravitreal injection of dexamethasone, and injection intravitreal antiangiogenic monoclonal antibodies, such as ranibizumab, bevacizumab, and aflibercept, alone or associated with photocoagulation, have shown efficacy and variables complications rates. Intravitreal injection of bevacizumab, a recombinant monoclonal antibody that acts directly against any active form of VEGF, has been shown to be effective in reducing macular thickness and improving visual acuity in the treatment of OVR. However, the need for multiple injections has been reported since the effects of intravitreal bevacizumab (as well as the other antiangiogenics) are short-lived. On one hand, Bevacizumab has the disadvantage that it is administered off-label; in addition each dose must be extracted from a vial for oncological use, which represents a risk of contamination if strictly rules of asepsis are not taken. On the other hand, the cost of each dose is lower than that of other products (ranibizumab, aflibercept) already approved for intraocular use. This allows that more patients have access to a prolonged treatment in underdeveloped or developing countries, such as Argentina. PURPOSE: To evaluate changes in visual acuity and macular thickness after intravitreal bevacizumab for the treatment of macular edema in patients with retinal vein occlusions (RVO). PATIENS AND METHODS: 39 consecutive patients with macular edema complicating RVO and treated with intravitreal injections of bevacizumab 1.25 mg/0.05 ml alone or associated with scattered peripheral laser photocoagulation, with a minimun follow-up of 18 months, were evaluated. Snellen visual acuity in LogMar units and macular thinckness measured by optical coherence tomography (OCT) were the end points. According to clinical and fluorescein angiographic presentation RVO were classified in branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO), and in non ischemic and ischemic. Wilcoxon test for paired variables, Mann Whitney for independant variables, and Student test for continuous variables, were used for statistical analysis. RESULTS: With a mean age of 66.8 years (SD: 13.65; range= 31-92 years), 62.5% of cases were CRVO and 37.5% BRVO. Mean number of injections was 4.11±161 (range= 1-6). Laser was performed in 25% of patients that did not respond to bevacizumab. At 18 months of follow-up, improvement of visual acuity and macular thickness was statistically significant (p=0.0001 and p=0.0009 respectively). BRVO showed better response to treatment than CRVO. Best visual results were obtained at first month (median= 1.00 P25= 0.5 P75= 1.30) and at 9 month (median= 0.8 P25= 0.5 P75= 1.20) after first injection, but no further improvement was observed beyond 9 months of treatment (p=0.84). No significant visual and macular thickness differences were obtained between patients treated with bevacizumab alone (p=0.116) and bevacizumab and laser (p=0.846). No ocular or systemic attributable-to-treatment side effects were observed. CONCLUSIONS: Bevacizumab was effective in improving visual acuity and reducing macular thinckness in patients with macular edema complicating RVO, especially in BRVO. No ocular or systemic complications were observed during follow-up. (AU)

Prognostic and predictive value of primary tumour side in patients with RAS wild-type metastatic colorectal cancer treated with chemotherapy and EGFR directed antibodies in six randomized trials.

BACKGROUND: There is increasing evidence that metastatic colorectal cancer (mCRC) is a genetically heterogeneous disease and that tumours arising from different sides of the colon (left versus right) have different clinical outcomes. Furthermore, previous analyses comparing the activity of different classes of targeted agents in patients with KRAS wild-type (wt) or RAS wt mCRC suggest that primary tumour location (side), might be both prognostic and predictive for clinical outcome. METHODS: This retrospective analysis investigated the prognostic and predictive influence of the localization of the primary tumour in patients with unresectable RAS wt mCRC included in six randomized trials (CRYSTAL, FIRE-3, CALGB 80405, PRIME, PEAK and 20050181), comparing chemotherapy plus EGFR antibody therapy (experimental arm) with chemotherapy or chemotherapy and bevacizumab (control arms). Hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS) for patients with left-sided versus right-sided tumours, and odds ratios (ORs) for objective response rate (ORR) were estimated by pooling individual study HRs/ORs. The predictive value was evaluated by pooling study interaction between treatment effect and tumour side. RESULTS: Primary tumour location and RAS mutation status were available for 2159 of the 5760 patients (37.5%) randomized across the 6 trials, 515 right-sided and 1644 left-sided. A significantly worse prognosis was observed for patients with right-sided tumours compared with those with left-sided tumours in both the pooled control and experimental arms for OS [HRs = 2.03 (95% CI: 1.69-2.42) and 1.38 (1.17-1.63), respectively], PFS [HRs = 1.59 (1.34-1.88) and 1.25 (1.06-1.47)], and ORR [ORs = 0.38 (0.28-0.50) and 0.56 (0.43-0.73)]. In terms of a predictive effect, a significant benefit for chemotherapy plus EGFR antibody therapy was observed in patients with left-sided tumours [HRs = 0.75 (0.67-0.84) and 0.78 (0.70-0.87) for OS and PFS, respectively] compared with no significant benefit for those with right-sided tumours [HRs = 1.12 (0.87-1.45) and 1.12 (0.87-1.44) for OS and PFS, respectively; P value for interaction <0.001 and 0.002, respectively]. For ORR, there was a trend (P value for interaction = 0.07) towards a greater benefit for chemotherapy plus EGFR antibody therapy in the patients with left-sided tumours [OR = 2.12 (1.77-2.55)] compared with those with right-sided tumours [OR = 1.47 (0.94-2.29)]. Exclusion of the unique phase II trial or the unique second-line trial had no impact on the results. The predictive effect on PFS may depend of the type of EGFR antibody therapy and on the presence or absence of bevacizumab in the control arm. CONCLUSION: This pooled analysis showed a worse prognosis for OS, PFS and ORR for patients with right-sided tumours compared with those with left-sided tumours in patients with RAS wt mCRC and a predictive effect of tumour side, with a greater effect of chemotherapy plus EGFR antibody therapy compared with chemotherapy or chemotherapy and bevacizumab, the effect being greatest in patients with left-sided tumours. These predictive results should be interpreted with caution due to the retrospective nature of the analysis, which was carried out on subpopulations of patients included in these trials, and because none of these studies contemplated a full treatment sequence strategy.