Browsing by Author "Palma, Silvia"

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    Benefit of adjuvant 5-fluorouracil based chemotherapy for colon cancer: a retrospective cohort study
    (SOC MEDICA SANTIAGO, 2016) Mondaca, Sebastian; Villalon, Constanza; Luis Leal, Jose; Zuniga, Alvaro; Bellolio, Felipe; Padilla, Oslando; Palma, Silvia; Garrido, Marcelo; Nervi, Bruno
    Background: Multiple clinical trials have demonstrated the benefits of adjuvant 5-fluorouracil-based chemotherapy for patients with resectable colon cancer (CC), especially in stage III. Aim: To describe the clinical characteristics of a cohort of CC patients treated at a single university hospital in Chile since 2002, and to investigate if chemotherapy had an effect on survival rates. Material and Methods: Review of a tumor registry of the hospital. Medical records of patients with CC treated between 2002 and 2012 were reviewed. Death certificates from the National Identification Service were used to determine mortality. Overall survival was described using the Kaplan-Meier method. A multivariate Cox proportional hazard regression model was also used. Results: A total of 370 patients were treated during the study period (202 in stage II and 168 in stage III). Adjuvant chemotherapy was administered to 22 and 70% of patients in stage II and III respectively. The median follow-up period was 4.6 years. The 5-year survival rate for stage II patients was 79% and there was no benefit observed with adjuvant chemotherapy. For stage III patients, the 5-year survival rate was 81% for patients who received adjuvant chemotherapy, compared to 56% for those who did not receive chemotherapy (hazard ratio (HR): 0.29; 95% confidence interval (CI): 0.15-0.56). The benefit of chemotherapy was found to persist after adjustment for other prognostic variables (HR: 0.47; 95% CI: 0.23-0.94). Conclusions: Patients with colon cancer in stage III who received adjuvant chemotherapy had a better overall survival.
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    Influence of SARS-CoV-2 mRNA Vaccine Booster among Cancer Patients on Active Treatment Previously Immunized with Inactivated versus mRNA Vaccines: A Prospective Cohort Study
    (2023) Mondaca Contreras, Sebastián Patricio; Walbaum, Benjamín; Corre, Nicole Le; Ferrés Garrido, Marcela Viviana; Valdés, Alejandro; Martínez-Valdebenito, Constanza; Ruiz-Tagle, Cinthya; Macanas Pirard, Patricia; Ross, Patricio; Cisternas, Betzabé; Pérez, Patricia; Cabrera, Olivia; Cerda, Valentina; Ormazábal, Ivana; Barrera Vásquez, Aldo Vincen; Prado, María E.; Venegas, María I.; Palma, Silvia; Broekhuizen, Richard; Kalergis, Alexis; Bueno, Susan M.; Espinoza, Manuel A.; Balcells Marty, María Elvira; Nervi Nattero, Bruno
    Cancer patients on chemotherapy have a lower immune response to SARS-CoV-2 vaccines. Therefore, through a prospective cohort study of patients with solid tumors receiving chemotherapy, we aimed to determine the immunogenicity of an mRNA vaccine booster (BNT162b2) among patients previously immunized with an inactivated (CoronaVac) or homologous (BNT162b2) SARS-CoV-2 vaccine. The primary outcome was the proportion of patients with anti-SARS-CoV-2 neutralizing antibody (NAb) seropositivity at 8–12 weeks post-booster. The secondary end points included IgG antibody (TAb) seropositivity and specific T-cell responses. A total of 109 patients were included. Eighty-four (77%) had heterologous vaccine schedules (two doses of CoronaVac followed by the BNT162b2 booster) and twenty-five had (23%) homologous vaccine schedules (three doses of BNT162b2). IgG antibody positivity for the homologous and heterologous regimen were 100% and 96% (p = 0.338), whereas NAb positivity reached 100% and 92% (p = 0.13), respectively. Absolute NAb positivity and Tab levels were associated with the homologous schedule (with a beta coefficient of 0.26 with p = 0.027 and a geometric mean ratio 1.41 with p = 0.044, respectively). Both the homologous and heterologous vaccine regimens elicited a strong humoral and cellular response after the BNT162b2 booster. The homologous regimen was associated with higher NAb positivity and Tab levels after adjusting for relevant covariates.