The overall aim of this thesis was to explore aspects of the subjective views and experiences of doctors as prescribers, focusing on responsibility for and factors of importance in achieving appropriate prescribing. To provide insights into the prescriber’s perspective the study designs were qualitative. In the first studies secondary care doctors’ perceptions of appropriate prescribing and influences in prescribing were investigated in interviews. The doctors perceived that appropriate prescribing needed continuous revision. From the perspective of the prescribers the definition of prescribing could be rephrased as: “the outcome of the recurring processes of decision making that maximises net individual health gains within society’s available resources”. Among the influences in prescribing were guidelines, colleagues and therapeutic traditions. In the subsequent studies the experiences of exchanging information regarding a patient’s drugs in an electronic patient medical record (e-PMR) shared between primary and secondary care and views of responsibility was explored, using focus groups with both primary and secondary care doctors. Considering the gap between health care levels, doctors’ views of responsibility in prescribing and exchange of information are of concern. The doctors expressed how they assume information to be in the e-PMR and active information transfer has decreased. On the other hand, they experienced an information overload in the e-PMR system. There is a need for improved and structured communication between health-care givers. Taking responsibility to review all the patient’s medications was perceived as important, but described as still not done. Lack of responsibility taken was often due to acts of omission, i.e. that doctors did not make needed changes to the list of medications due to different barriers. The barriers rested both with individual doctors and the system, but to ensure solutions that are realisable in practise, perspectives of the doctors need to be taken into consideration when overcoming those barriers.

The central role of Src in the development of several malignancies including breast cancer and the accumulating evidence of its interaction with receptor tyrosine kinases (RTK), integrins and steroid receptors have identified it as an attractive therapeutic target. In the current study we have evaluated the effect of a Src/Abl kinase inhibitor SKI-606, on breast cancer growth, migration, invasion and metastasis. Treatment of human breast cancer cells MDA-MB-231 with SKI-606 caused a marked inhibition of cell proliferation, invasion and migration by inhibiting MAPK and Akt phosphorylation. For in vivo studies MDA-MB-231 cells transfected with the plasmid encoding green fluorescent protein (GFP) [MDA-MB-231-GFP] were inoculated into mammary fat pad of female BALB/c nu/nu mice. Once tumor volume reached 30-50 mm3, animals were randomized and treated with vehicle alone or 150 mg/kg of SKI-606 by daily oral gavage. Experimental animals receiving SKI-606 developed tumors of significantly smaller volume (45-54%) as compared to control animals receiving vehicle alone. Analysis of lungs, liver and spleen of these animals showed a significant decrease in GFP positive tumor metastasis in animals receiving SKI-606 at a dose that was well tolerated. Western blot analysis and immunohistochemical analysis of primary tumors showed that these effects were due to the ability of SKI-606 to block tumor cell proliferation, angiogenesis, growth factors expression and inhibition of Src mediated signalling pathways in vivo. Together the results from these studies provide compelling evidence for the use of Src inhibitors as therapeutic agents for blocking breast cancer growth and metastasis.

Diss. (sammanfattning) Linköping : Univ. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

Introdução: O Tratamento Preventivo com Isoniazida (TPI) é indicado para os pacientes com HIV/aids e infecção latente por Micobacterium tuberculosis (ILMTb) para os quais não haja contraindicação à Isoniazida. Entretanto, barreiras de acesso podem impedir que os pacientes realizem este tratamento. Objetivos: O presente estudo avaliou a taxa de acesso à prescrição médica do TPI em sujeitos com HIV/aids e ILMTb em seguimento em um serviço especializado de HIV/aids no período de fevereiro de 2005 a dezembro de 2009. Para os sujeitos que não tiveram acesso à prescrição do TPI, buscou-se, em prontuário, justificativas para esta conduta. Também foi identificado o perfil epidemiológico, clínico e demográfico dos sujeitos com HIV/aids e ILMTb e foi descrita a característica do médico que solicitou o teste tuberculínico (TT) e do que prescreveu o TPI. Métodos: No período de 02 de fevereiro de 2005 a 31 de dezembro de 2009 que estavam em seguimento no SEAP HIV/Aids foram incluídos sujeitos com HIV/Aids e ILMTB, diagnosticada através do Teste Tuberculínico (TT). Informações referentes às variáveis analisadas foram coletadas nos prontuários médicos e através de consulta ao Sistema de Informação e Gestão Hospitalar (SIGH) - Módulo Farmácia. Resultados: Foram incluídos 238 sujeitos dentre os 310 que tiveram TT > 5 mm no período do estudo. Destes, 70,6% (168) eram do sexo masculino; a média de idade foi de 42,6 anos; 88,2% (210) dos sujeitos tiveram acesso à prescrição do TPI. O acesso à prescrição do TPI foi associado à idade, ao tamanho da resposta ao TT, ao nadir de Linfócitos TCD4+ dos sujeitos em TARV e à presença de cicatriz de BCG. Sujeitos mais jovens, com resposta ao TT igual ou maior do que 10 mm e com cicatriz de BCG tiveram maior acesso à prescrição do TPI. Uma das questões a ser explorada em futuros estudos se refere aos fatores que influenciam, ou não, a decisão do profissional de introduzir este tratamento na situação em que o mesmo está recomendado tecnicamente. Conclusão: Os sujeitos mais jovens, com melhor situação imunológica de base, maior valor de resposta ao TT e com presença da cicatriz de BCG, tiveram maior acesso ao TPI. Neste estudo foi evidenciada a necessidade de que as instituições de saúde invistam em educação continuada de seus profissionais para elevarem a cobertura de ações programáticas, como é o tratamento da ILMTB, previsto nos programas nacionais de tuberculose e de HIV/aids. Além disso, é necessário que as equipes interdisciplinares atuem de forma integrada e harmônica, para garantir o acesso às ações de saúde. É possível identificar, porém muitas barreiras que restam para a serem rompidas de modo que os cidadãos que vivem com HIV/aids tenham acesso a este e aos demais tratamentos de que tenham necessidade / Background: Isoniazid Preventive Treatment (IPT) is recommended for patients with HIV/AIDS and Latent Infection by Mycobacterium tuberculosis (ILMTb) and no contraindication to isoniazid. However, access barriers may prevent patients to undergo to this treatment. Objectives: This study evaluated the rate of access to the prescription of IPT in subjects with HIV/aids and ILMTb followed up in a specialized HIV/aids from February 2005 to December 2009. For subjects who did not have access to the prescription of IPT, we sought, on records, justification for this conduct. Also, the epidemiological, clinical and demographic profile of individuals with HIV/AIDS and ILMTb and the characteristic of the doctor who requested the tuberculin skin test (TST) and prescribed IPT were identified. Methods: from 02 February 2005 to 31 December 2009 subjects followed up at SEAP HIV/aids with HIV/aids and ILMTB, diagnosed by Tuberculin Test (TST) were included. Information was collected from the medical records and from the Hospital Information and Management System (SIGH) - Pharmacy Module. Results: 238 subjects were included, among the 310 who had TST > 5 mm during the study period. Of these, 70.6 % (168) were male and the average age was 42.6 years, 88.2 % (210) had access to the prescription of IPT. Access to IPT prescription was associated with age , size of response to TST, nadir of lymphocytes CD4 + in subjects on ART and presence of BCG scar: younger subjects with response to TST equal to or greater than 10 mm and BCG scar had higher access rate to IPT prescription. An issue to be explored in the future refers to variables that influence the professional\'s decision to prescribe this treatment when it is technically recommended. Conclusion: younger subjects with better immune status at baseline, greater response to TST and presence of BCG scar, had more access to IPT. This study highlighted the need of educational programs for health professionals, in order to improve the coverage of activities devoted to reduce morbidity and mortality in HIV/aids patients, as is the treatment of ILMTB, recommended in national tuberculosis and HIV/AIDS programs. Furthermore, it is crucial, for interdisciplinary health teams, to operate in an integrated and harmonious way, to ensure, for HIV/aids patients, a healthy and longer life

Transplante de medula óssea (TMO) é um procedimento terapêutico que tem como o objetivo a substituição da medula óssea doente por outra saudável. É utilizado em pacientes oncológicos e pode representar a cura da malignidade hematológica ou o resgate da medula óssea para a continuidade do tratamento antineoplásico. No TMO são empregadas drogas com alta toxicidade que agem ao nível sistêmico e que podem causar severos danos ao organismo. Esses danos resultam em complicações diversas que irão influenciar o prognóstico e sobrevida do paciente. As complicações pulmonares são associadas a altas taxas de mortalidade, sobretudo quando a ventilação mecânica (VM) é necessária. Ainda não há consenso na literatura quanto às causas, os fatores de risco e o tratamento adequado. Este estudo teve como objetivo identificar os fatores preditivos para insuficiência respiratória (IRP) em paciente oncológicos após o TMO autólogo e investigar o impacto da ventilação não-invasiva (VNI) na evolução clínica destes pacientes. Foi realizado o levantamento retrospectivo de 161 pacientes submetidos ao TMO autólogo no Hospital A.C. Camargo entre 1995 e 2005. Houve forte associação de IRP e óbito (p< 0,001) e também observamos associação com mucosite (p=0,016) e etilismo (p=0,036), essa associação permaneceu significante na análise multivariada [mucosite (p=0,004) e etilismo (p=0,02)]. De acordo com a análise de sobrevida encontramos associação com o maior número de regimes de quimioterapia no passado (p= 0.005), mucosite (p= 0.029), etilismo (p= 0.044) e redução da capacidade de difusão de monóxido de carbono (p=0.048). Em nosso estudo a taxa de mortalidade permanece alta para aqueles pacientes que desenvolvem IRP e necessitam de VM. A VNI não demonstrou efeito protetor na sobrevida dos pacientes que evoluíram com IRP. A mucosite mostrou-se um fator de piora no prognóstico destes pacientes devendo ser agressivamente evitada e tratada. O impacto do etilismo na incidência de insuficiência respiratória (IRP) e mortalidade destes pacientes merece destaque especial com necessidade de mais pesquisas. O stress oxidativo parece ter um importante efeito causal para as complicações pulmonares após o TMO podendo ser potencializado pelo etilismo. O maior número de esquemas de quimioterapia no passado aumentou a mortalidade, isso poderia representar pacientes com neoplasias mais resistentes ao tratamento ou pacientes que foram expostos ao efeito cumulativo das drogas. A capacidade de difusão de monóxido de carbono é um teste bastante útil para prever risco de óbito / Bone marrow transplantation (BMT) is a therapeutic procedure to replace unable marrow for another healthy one. Its used in cancer patients to cure or refresh marrow to keep the cancer treatment. Respiratory failure (RF) after BMT is associated with high mortality specially when mechanical ventilation (MV) is needed, it may be due to treatment-related toxicity, infection, or immunologic insufficiency. Many studies have trying to identify causes, predicting factors and response for the usual treatment, but until now there is no agreement in literature. The aim of this study is to identify which factors evaluated in routine anamnesis and exams pretransplant can affect the prognosis of those patients. We retrospectively collected variables in 161 consecutive cancer patients who had undergone autologous BMT. The variables obtained from the in-hospital period were submitted to univariated and multivariated stepwise logistic regression analyses. Survival analysis also was computed in 100 days follow up. There were highest association for respiratory failure (RF) with death (p<0.001) and we also found a significant association with alcohol abuse (p =0.036) and mucositis (p=0.016), and those variables remained statically significant in multivariated analysis [mucositis (p=0.004) and alcohol abuse (p=0.02)]. According to survival analysis we found significance for the major number of chemotherapy regimens received in the past (p= 0.005), mucositis (p= 0.029), alcohol abuse (p= 0.044) and decreased monoxide carbon diffusion (p=0.048). In our study the mortality rate remains high for those patients who develop RF and need MV. It seems not to have impact what kind of ventilatory support is used (invasive or non-invasive ventilation). Mucositis needs special attention because treating it we can be preventing RF and decrease mortality rates. The effect of alcohol abuse in mortality rate and RF deserve a special attention because its socially accepted and his deleterious action its not explained. The oxidative stress seems to have an important main effect over post-transplant complications and it can be increased by alcohol abuse history. The major number of chemotherapy regimens received in the past increase mortality, it could represent patients who had baseline disease more difficult to treat, more resistant, or patients who were exposed to a cumulative side effect of drugs. Monoxide carbon diffusion is a useful test to identify the risk for death

Introdução: O carcinoma de células escamosas (CEC) do canal anal é uma neoplasia pouco frequente, correspondendo a 1-5% dos tumores intestinais. Entretanto, o risco de CEC do canal anal vem crescendo. O tratamento padrão do CEC de canal anal nos estádios II-III consiste em 5-fluorouracil infusional associado a mitomicina-C e radioterapia, desde 1974. Estudos clínicos com o objetivo de identificar novos esquemas terapêuticos mais convenientes para câncer do canal anal devem continuar. Métodos: Pacientes com CEC de canal anal T2-4N0M0 ou T (qualquer) N1-3M0, com bom performance clínico, função renal e hematológica normais foram tratados com capecitabina 825 mg/m2 12/12 horas durante a radioterapia associada a dose única de mitomicina-C 15 mg/m2 no Dia 1. O objetivo primário do estudo foi determinar a taxa de controle local em 6 meses da associação de capecitabina, mitomicina-C e radioterapia em pacientes com câncer do canal anal. Os objetivos secundários foram determinar a taxa de toxicidade aguda graus 3-4, conforme os critérios da CTCaev4.0, taxa de resposta completa 6 semanas após término da quimio-radioterapia, sobrevida global e livre de progressão e taxa de colostomia em 1 ano. O tamanho da amostra foi calculado usando a ferramenta \"estágio único de Fleming\". Considerando 85% de eventos esperados (taxa de controle local em 6 meses), 1 desvio padrão e 5% de erro alfa, o tamanho ideal da amostra foi de 51 pacientes. Resultados: De novembro/2010 a fevereiro/2014, 51 pacientes foram incluídos, sendo avaliados 43 pacientes. Dezessete pacientes (39,5%) tinham estádio II, 11 (25,6%) estádio IIIA e 15 (34,9%) estádio IIIB. O seguimento mediano foi de 23,1 meses. Entre os pacientes que foram avaliados em 6 meses, 3 (7%) apresentaram resposta clínica parcial, 37 (86%) tiveram resposta clínica completa e 3 (7%) apresentaram progressão de doença. O controle loco-regional em 6 meses foi de 86%. Em relação às toxicidades graus 3-4, observaram-se diarreia grau 3, em 4,6% dos pacientes, radiodermite grau 3, em 23,2%, vômitos grau 3, em 2,3%, plaquetopenia graus 3-4, em 6,9%, leucopenia grau 3, em 6,9%, e linfopenia grau 3, em 11,6%. Um paciente HIV positivo (2,3%) apresentou choque séptico grau 4, pneumonia grau 4, meningoencefalite herpética grau 4 e síndrome de ativação macrofágica grau 4. A taxa de colostomia foi de 18,6%. Conclusão: Capecitabina e mitomicina-C são um tratamento bem tolerado em pacientes com carcinoma de canal anal, com controle loco-regional em 6 meses em 86% dos pacientes. Palavras-chave: carcinoma de células escamosas, câncer anal, capecitabina, radioterapia, mitomicina-c / Background: Squamous cell carcinoma (SCC) of the anal canal is an uncommon malignancy accounting for 1-5% of intestinal tumors; however, its incidence has been increasing. Treatment for stage II and III anal canal SCC is infusional 5-fluorouracil associated with mitomycin and radiotherapy, since 1974. More convenient treatments for patients are needed. Methods: Patients with SCC of anal cancer T2-4N0M0 or T (any) N1-3M0, with good performance status, normal blood, and renal function were treated with capecitabine 825 mg/m2 bid during radiotherapy associated with a single dose of mitomycin 15 mg/m2 on day 1. Primary objective was local control rate at 6 months determined by clinical examination and radiological assessment. Sample size was calculated using Fleming single stage design. Results: From november/2010 to february/2014 51 patients were initially included, however 43 patients were assessed. Seventeen patients (39.5%) were stage II, 11 patients (25.6%) stage IIIA, and 15 patients (34.9%) stage IIIB. Four patients (9.3%) were HIV-positive, while 39 (90.7%) were HIV-negative. Median follow-up was 23.1 months. Among patients who finished the treatment and were reevaluated at 6 months 3 patients (7%) presented partial response, 37 patients (86%) had complete response, and 3 patients developed progression of the disease (7%). Regarding grade 3-4 toxicities, 10 patients (23.2%) had grade 3 radiodermitis, 3 patients (6.9%) had grade 3-4 thrombocytopenia, 5 (11.6%) had grade 3 lymphopenia, 1 patient (2.3%) had grade 3 vomiting, 2 patients (4.6%) had grade 3 diarrhea and 3 patients (6.9%) had grade 3 leukopenia. One HIV+ patient had septic shock, pneumonia, herpetic encephalitis and macrophage activation syndrome. Colostomy rate was 18.6%. Conclusions: Capecitabine and mitomycin with radiotherapy seem to be a safe treatment for SCC of the anal cancer, with a complete response rate in 6 months of 86%

INTRODUÇÃO: O presente trabalho teve como objetivo elaborar análise custoefetividade do esquema de quimiorradioterapia com cisplatina (estratégia 2) comparado ao tratamento radioterápico (estratégia 1) para pacientes portadores de CECCP localmente avançado não elegíveis para tratamento cirúrgico. MÉTODOS: levantamos dados prospectivos de 33 pacientes na estratégia 2 e dados retrospectivos de 29 pacientes tratados no HC-FMUSP e Hospital A.C. Camargo, (estratégia 1). Consideramos a tabela de reembolso do Sistema Único de Saúde (perspectiva SUS) e custos do HC-FMUSP com honorários profissionais, medicamentos, demais insumos e depreciação de equipamentos (perspectiva Institucional). A medida de efetividade foi 1 ano de vida ganho, livre de progressão da doença (SLPD). Calculamos a Razão Incremental Custo Efetividade (RICE). RESULTADOS: 31% dos pacientes da estratégia 1 e 58% na estratégia 2) tiveram 1 ano de SLPD. Na perspectiva SUS o custo total por paciente na estratégia 1 foi de R$ 2.798,52 e R$ 4.938,11 na estratégia 2. Na perspectiva institucional os custos foram R$ 26.798,52 e R$ 5.040,79, respectivamente. A RICE na perspectiva SUS foi de R$ 7.924,00 reais por ano de vida ganho e R$ 8.912,71 na perspectiva institucional. CONCLUSÃO: nas duas perspectivas a estratégia 2 se mostrou custo-efetiva, sendo o custo incremental considerado aceitável, segundo diretrizes do Banco Mundial. / INTRODUCTION: The present study aims to conduct a cost-effectiveness analysis comparing chemoradiotherapy with cisplatine and radiotherapy alone, to treat inoperative advanced head and neck cancer. METHODS: we collected data from 29 patients in a prospective study on chemoradiotherapy with cisplatin, conducted at Hospital das Clínicas HC-FMUSP,(strategy 2). For strategy 1, we collected retrospective data of 33 patients treated with radiotherapy at HC-FMUSP and Hospital A.C. Camargo. We considered only direct costs (personnel, drugs, material and equipment depreciation). We considered, the National Health Service (SUS) reimbursement parameters as the National Security System perspective, and HC-FMUSP costs as the institutional perspectives. We measured effectiveness as one year of diseasefree life gained. We collected costs and effectiveness data and calculated the cost-effectiveness incremental ratio ICER, which expresses additional costs per life year gained, in strategy 2, compared to strategy 1 RESULTS: 31.0% of the patients treated in strategy 1 lived more than 12 months, without disease progression, compared to 58.0% of the patients in strategy 2. According to SUS perspective, the total cost per patient in strategy 1) is R$ 2.798,52 and R$ 4.938,11 in strategy 2. Considering the institutional perspective, total costs are R$ 2.634,36, and R$ 5.040,79 respectively. In SUS perspective, the ICER ratio of strategy 2 compared to 1 is R$ 7.924,00 per lifes year gained. In the institutional perspective, ICER is R$ 8.912,71. We conducted a one way sensitivity analysis to verify our calculations. CONCLUSION: Chemoradioterapy with cisplatin proved more cost-effective than radiotherapy. Using the World Bank guidelines, wich considers the countries GDP per capita an acceptable cost per additional year of life (R$ 12.491,00 in 2006), the incremental cost of both is acceptable.

INTRODUÇÃO: O câncer colorretal metastático (CCRm) é uma doença clinicamente e molecularmente heterogênea. Os pacientes apresentam diferentes prognósticos e respostas variáveis às terapias direcionadas contra o tumor. Alterações na função do sistema de reparo do DNA (deficiency mismatch repair - dMMR) estão associadas com o fenótipo de instabilidade de microssatélites e bom prognóstico em tumores de estádio inicial. No entanto, dMMR é raro no CCRm e pouco se sabe sobre sua influência na taxa de resposta (TR) ao tratamento. Nosso objetivo primário foi comparar a TR, de acordo com o status dMMR, nos pacientes com CCRm. Os desfechos secundários foram TR, conforme RAS e BRAF mutados, e a sobrevida global (SG), de acordo com dMMR. MÉTODOS: Estudo retrospectivo com grupo controle que comparou a TR por RECIST 1.1 em pacientes com CCRm, tratados com quimioterapia (QT) sistêmica, de acordo com o status dMMR. Os dados clínicos foram coletados, retrospectivamente, dos prontuários médicos. Todas as imagens foram digitais e recuperadas para avaliação de resposta por um único radiologista, cego quanto ao status dMMR. dMMR foi definido como a perda de expressão imuno-histoquímica em pelo menos um dos genes MMR (MLH1, MSH2, MSH6 e PMS2). Mutações em RAS e BRAF foram investigadas por meio de sequenciamento gênico. Os casos foram os pacientes com dMMR, e os controles, com MMR proficiente (pMMR), selecionados de forma consecutiva, em proporção de 1:2. Com base em características clínicas e moleculares, os indivíduos dMMR foram classificados como provável Lynch ou dMMR esporádico. Estatística descritiva foi usada para resumir os resultados. A associação entre dMMR e os resultados específicos de cada grupo foram analisados pelo teste do qui-quadrado, e para a avaliação de SG mediana, curvas de Kaplan-Meier e teste log-rank foram utilizados. Valores bicaudados de p < 0.05 foram considerados significativos. RESULTADOS: Entre janeiro de 2009 e janeiro de 2013, de 1270 pacientes, 762 foram elegíveis e rastreados para dMMR: N = 27 (3,5%) tiveram dMMR e N = 735 (96,5%) tiveram pMMR. Dada a raridade, foram incluídos 14 indivíduos com dMMR fora do período de inclusão, totalizando 41 casos (pacientes dMMR) e 84 controles (pacientes pMMR). Em análise por intenção de tratamento, considerando os pacientes que receberam pelo menos uma dose de QT baseada em oxaliplatina (N dMMR = 34), aqueles com dMMR apresentaram TR numericamente menor, comparados aos pMMR (11.7% vs 28.6%, OR: 0.33, IC 95%: 0.08-1.40, p = 0.088). Em análise por protocolo, incluindo apenas os pacientes que preencheram os critérios de inclusão (N dMMR = 33), aqueles com dMMR mantiveram TR menor à QT baseada em oxaliplatina em primeira linha, em comparação aos doentes pMMR, embora estatisticamente não significante (12.1% vs 28.6 %, OR: 0.34, IC 95%: 0.09-1.18, p = 0.102). Ainda neste contexto, os pacientes com possível Lynch apresentaram maior TR do que os indivíduos com provável dMMR esporádico (16% vs 0). Mutações em RAS ou BRAF não influenciaram na TR ou sobrevida. O status \"provável dMMR esporádico\" foi fator de pior prognóstico, quando todos os pacientes da amostra (N dMMR = 41) foram considerados. CONCLUSÃO: Este estudo sugere que dMMR é preditivo de resistência à quimioterapia baseada em oxaliplatina, como mostrado por outros estudos. Aparentemente, essa resistência é mais acentuada nos pacientes dMMR esporádicos, sugerindo heterogeneidade biológica nos doentes com CCRm e dMMR / BACKGROUND: Metastatic colorectal cancer (mCRC) is a clinically and molecularly heterogeneous disease, where patients present different prognosis and variable responses to cancer-directed therapies. Alterations in the function of DNA deficiency mismatch repair (dMMR) genes are associated with microsatellite instability and good prognosis in early stage tumors. However dMMR dysfunction is rare in mCRC and little is known about its influence on treatment response rate (RR). Our primary endpoint was to compare the RR of mCRC patients according to dMMR status and to explore differences between patients with likely sporadic versus likely Lynch-related tumors. Secondary endpoints were RR according to RAS and BRAF mutation status, and survival times as per dMMR status. METHODS: Retrospective study with control group that compared the RR by RECIST 1.1 in patients with mCRC treated with systemic chemotherapy according to dMMR status. Clinical data were collected retrospectively from medical charts. All images were digital and were retrieved for response evaluation by a single radiologist blinded to dMMR results. dMMR status was defined as loss of immunohistochemistry expression in at least one of the MMR genes (MLH1, MSH2, MSH6 e PMS2). RAS and BRAF mutations were investigated through next generation sequencing. Cases were defined as dMMR and controls, as proficient MMR (pMMR) patients, in a 1:2 fashion. Based on clinical and molecular features, dMMR patients were classified as likely Lynch or sporadic. Descriptive statistics was used to summarize the results. The association between dMMR and outcomes of each group were analyzed by chi-square test; estimates of median overall survival were done by the Kaplan-Meier method and comparisons, by the log-rank test. Two-tailed p values < 0.05 were considered significant. RESULTS: From January 2009 to January 2013, out of 1270 patients, 762 were eligible and screened for dMMR: N = 27 (3.5%) had dMMR and N = 735 (96.5%) had pMMR. Given the rarity, 14 dMMR cases outside the inclusion period were included, with a total of 41 cases (dMMR patients) and 84 controls (pMMR patients). By intention-to-treat analysis, considering all patients who received at least one dose of oxaliplatin-based chemotherapy (N dMMR = 34), those with dMMR had numerically lower RR, compared with pMMR (RR = 11.7% vs 28.6%, OR: 0.33, 95% CI: 0.08-1.40, p = 0.088). As per protocol analysis, considering only the patients who met inclusion criteria (N dMMR = 33), those with dMMR status persisted with numerically, but non-significant, lower RR to first-line oxaliplatin-based chemotherapy compared with pMMR (12.1% vs 28.6%, OR: 0.34, 95% CI: 0.09-1.18, p = 0.102); also, patients with likely Lynch-related mCRC presented higher RR than subjects with probable sporadic dMMR (16% vs 0). Either survival or RR was influenced by RAS or BRAF mutations. Probable sporadic dMMR status was a poor prognostic factor when all patients in the sample (N dMMR = 41) were analyzed. CONCLUSION: This study suggests that the dMMR phenotype is predictive of resistance to oxaliplatin-based chemotherapy, as shown by other studies. Apparently, such resistance is more pronounced in the sporadic dMMR patients, suggesting biological heterogeinity within the dMMR mCRC patients