e22207 Background: It is well known cancer patients may present both hemorrhagic and thrombotic abnormalities and these phenomena are difficult to diagnose and treat. Thrombotic phenomena are developed clinicly in 15% in cancer patients and it’s higher in adenocarcinomas and myeloprolipherative disorders. These complications can be the consequence of coagulations factor direct activation or chronic DIC, because of the acquired capacity of neoplastic cells for starting coagulation cascade. Methods: In this study an untreated cancer patients group were compared with another healthy controls group, older than 14 years. Patients before treatment and controls were laboratory tested. A t – test for independent samples was employed. Results: Number: patients group: 66, control group: 73. Median age: patients: 50 (17-78). Controls: 52 (18 -93). Sex: Patients: men: 35%, women: 65%. Controls: men: 52%, women: 48%. Malignancies: breast cancer 9.7%; gastric carcinoma 8.1%; cervical carcinoma 6.5%; NH lymphomas 6.5%, unknown origen metastatic carcinoma 4.8%; oral carcinoma 4.8%. Clinical stages: I: 6.3%; II: 6.3%; III: 22.9%; IV: 62.5% (metastatic) 47.9%. Thrombotic antecedents in patients group: 19.7%. There were significant differences in: Platelets count: patients: 281121, controls: 307745 (p<0.001). Protein C: 0.87 and 3.81 UI/mL, respectively (p < 0.001). Antithrombin III: 97 and 101% (p<0.001). Plasminogen: 92.9 and 101.1% (p < 0.001). Lupus anticoagulant (RVV time): 27 and 25.6” (p<0.001). There were no significant differences in PT: 18.3 and 16.9” and PTT: 31 and 34”. The same significant differences were got when the patients of every clinical stage were compared with control patients. There were no differences when the patients of every clinical stage were compared among themselves, nor between sex. Conclusions: This study shows cancer patients may have many coagulation abnormalities: anticoagulant system defects and fibrinolytic system hipoactivity, demonstrated by the significant differences found in antithrombin III, protein C and plasminogen levels between patients and controls groups. It is suggested to practice these tests to cancer patients, even without clinical coagulation disorders, to stablish prophylactic measures.

e18761 Background: Cancer has been described as a risk factor for worse prognosis in people with Covid-19. However, there are few studies informing on the characteristics of cancer patients that have asymptomatic SARS-cov2 infection. The ACHOCC-19 study included asymptomatic patients. Methods: Analytical cohort study of patients with cancer and SARS-cov2 infection in Colombia. From April 1 to October 31, 2020, we collected data on demographic and clinical variables related to cancer and COVID-19 infection. We describe the characteristics and outcomes of patients who had no symptoms of COVID19. Association between outcomes and prognostic variables was analyzed using logistic regression models. Results: We included 742 patients, of which 205 (27.6%) were asymptomatic. Of these 62.2% were older than 61 years, 66% were women, 1.42% were smokers. The most frequent malignancy was breast cancer (25%), followed by colon-rectum (14.6%), sarcoma/soft tissues (5.66%) and lung cancer (5.19%). Patients were more likely to be asymptomatic if they had fewer comorbidities (0-1 comorbidities: 84% asymptomatic, 2 comorbidities: 10.85%, more than 2 comorbidities: 5.15%). 90.5% lived in urban areas and 53.37% had low income. 35.4% of patients had metastatic disease, 8.7% had progressive cancer, 40% had stable disease or partial response. No patient had an ECOG PS of 4 or more, and only 1.91% had ECOG 3. In logistic regression analysis statistically significant associations for having symptomatic disease included: man, presence of 1, 2 or > 2 comorbidities, ECOG 1,2 or 3 and cancer in progression. On the other hand, the statistically significant ORs for having asymptomatic disease were age between 18 and 30 years old, cancer in remission and receiving non-cytotoxic treatment. Table sumarizes ORs and their respective 95% CIs of the variables adjusted in the logistic regression model. Conclusions: In our stumdy, cancer patients had a higher probability of asymptomatic COVID-19 infection if they were women, between the ages of 18 and 30 years, had cancer in remission , ECOG 0 and no comorbidities. This is the first cohort of patients with cancer and asymptomatic covid 19 with a significant sample size in Latin America.[Table: see text]

e18721 Background: In our experience during the first year of development of ACHOC-C19 study, we observed 26% mortality in patients with cancer and COVID 19 infection. The impact of vaccination was not evaluated prior to the implementation of this strategy worldwide in this kind of population. It was proposed to evaluate the effectiveness of immunization during the second phase of our investigation. Methods: Cohort study derived from the National Registry of Patients with Cancer and COVID-19 (ACHOCC-19). Data were collected from June 2021 since vaccine was available. Patients were: older than 18 years, diagnosed with cancer (solid tumors), treated and/or under follow-up, and with COVID-19 infection. The comparative analysis of the vaccinated and non-vaccinated cohort is presented. Outcomes included: all-cause mortality within 30 days of infection diagnosis, hospitalization, and mechanical ventilation. Effect estimation was performed through relative risk (RR) and multivariate analysis for each event, using generalized linear models of the binomial family. Results: 896 patients were included, 470 were older than 60 years (52.4%) and 59% women (n = 530). 172 patients were recruited in the vaccinated cohort and 724 in the non-vaccinated cohort (ratio: 1 to 4.2). The cumulative incidence of hospitalization among the unvaccinated was 42.4% (n = 307), and among the vaccinated, 29% (n = 50); invasive mechanical ventilation requirement was 8.4% (n = 61) in unvaccinated, and 4.6% (n = 8) in vaccinated. The cumulative incidence of mortality from all causes in the unvaccinated was 17% (n = 123) and in the vaccinated 4.65% (n = 8). Table summarizes the multivariate analysis. The adjusted RR for mortality for the unvaccinated is 3.4 (95% CI: 1.7-6.8), for hospitalization 1.36 (95% CI: 1.08-1.72), and for mechanical ventilation 2.1 (95% CI: 1.02-4.2). Conclusions: The incidence of complications and death in patients with cancer and COVID-19 infection is significantly higher in those who have not received a vaccination schedule compared to those who have been vaccinated. Immunization should be promoted and intensified in this population group.[Table: see text]