1628P Impact of COVID-19 pandemia on the diagnosis of breast cancer in one region of north of Portugal: One year experience

Abstract

Background: The onset of COVID-19 pandemic forced lockdown and halted breast cancer screening programs. We aimed to investigate the impact of COVID-19 on the new diagnosis and staging of breast cancer. Methods: In this cohort study, we included all patient with new diagnosis of breast cancer who were admitted to our Hospital (Hospital Pedro Hispano, Matosinhos, Portugal), between March 2019 and March 2021. We collected data on baseline clinical conditions such as age, stage at diagnosis and treatment. We created two different groups were created: 1st group- before COVID-19 pandemia (March 1, 2019 to March 16, 2020);2nd group - COVID-19 pandemia (March 17, 2020 to March 31, 2021). A comparative assessment between groups was carried out. Results: Were included 483 patients;n=289 in the 1st group and n= 194 in the 2nd group. The median age was 60 years old in the 1st group and 59 years old in the 2nd group. In the 1st group, 13% patients were diagnosis with ductal in situ carcinoma (DCIS), 51% in stage I, 24% in stage II, 9.5% in stage III and 3% in stage IV. In 2nd group, 9% had DCIS, 30% were in stage I, 40% in stage II, 11% in stage III and 10% in stage IV. Stage at diagnosis was significantly higher in the 2nd group (p< 0.001) This situation was mainly due to tumour size (T). In the 1st group, most patients (n=91;38%) had tumour size between 10 e 20mm (T1c in TNM classification). One the other hand, 40% (n=78) of patients included in the 2nd group had tumour size between 20 e 50mm (T2), with significant differences between them (p=0.004). No difference was found between groups in nodular involvement (p=0.189), with the majority of patients (∼50% in both groups) presenting without nodular involvement (N0 in TMN classification). 10% of patients in 2nd group and 3% in 1st group had metastatic disease at diagnosis, with differences between them (p=0.006). 49% (n=119) of patients in 1st group and 52% (n=100) in the 2nd group were treated with chemotherapy, without differences between those groups. Conclusions: Our results show that during one year after COVID-19 pandemia the incidence of breast cancer decreased, and patients were diagnosis in more advanced stages. This situation could have been related to patient referral to non COVID-19 Hospitals or correspond to a true sub-diagnosis. Legal entity responsible for the study: M. Vilaca. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.