1601P SARS-CoV-2 serological response in cancer patients in the Principality of Andorra (COVONCO study)

Royo-Cebrecos, C.; Ambatlle, I.; Robert, Ï.; Buldon, J. M.; Vilanova, D.; Pons, J. Serrano; Baillés, E.; Mahia, E.; Pujadas olano, J.; Cobo, F.; Rodriguez, S. Albiol

Background: Little is known about the duration of SARS-CoV-2 antibodies and the factors that influence their durability in oncologic patients. This study aims to study serological response over time by means of a follow-up period of 6, 9 and 12 months. This study also compares patient characteristics by duration of antibody seroprevalence (≥6 months and <6 months) according to treatment groups within the oncological population. Methods: Observational, unicentric, prospective cohort study. All adult patients with cancer diagnosis within 5 years (2016-April 2020) who accepted participation were included since May 2020. During subsequent months, a comprehensive follow-up of these patients has been performed. Demographic and clinical data was taken from medical records (HCIS, software SAAS) and inputted into a web form (https://forms.epidemixs.org/form/study/covoncoand). Results: 182 oncologic patients with complete data who underwent population serological screening in May 2020 were selected. At baseline, 152 (83.51%) patients had solid tumors and 30 (16.48%) presented with metastatic diseases. Breast cancer was the main primary cancer site with 49 (26.92%) patients. 102 (56.04%) patients received active anti-cancer treatment, of which 48 (47.06%) received chemotherapy, 25 (24.51%) hormonal therapy, 64 (62.74%) biologics and 8 (7.84%) radiotherapy. Of these, 14 patients were seropositive (7.69%). At the 6-month analysis, 156 patients underwent a serological test (1 patient died and 25 did not perform the test) and 10 patients (6.41%) were seropositive. Among the 14 seropositive patients at baseline, only 3 (30.0%) remained positive at 6 months. Conclusions: Seroprevalence at baseline and at 6 months was lower than observed in the general population in Andorra. Only 3 (30%) patients remained positive at 6 months. No significant differences were observed between overall seroprevalence and anti-cancer treatments. Drawing definitive conclusions is limited by a small sample size. Legal entity responsible for the study: Servei Andorrà d'Atenció Sanità ria. Funding: Servei Andorrà d'Atenció Sanità ria (SAAS). Disclosure: All authors have declared no conflicts of interest.