Background: COVID-19 has forced governments to make drastic changes to the health care system. While these may have reduced COVID-19 morbidity/mortality, there have been unintended consequences on society and non-COVID-19 health issues. Although initial data start to inform us how to care for cancer patients during COVID-19, there is as yet no long-term follow-up. To start making informed decisions about cancer care, it is crucial to understand the scale of COVID-19 infection in cancer patients. Therefore, we introduced swab testing for patients visiting Guy’s Cancer Centre.

Methods: Our Centre in South-East London treats approximately 8,800 patients annually (including 4,500 new diagnoses) and is one of the largest Comprehensive Cancer Centres in the UK at the epicenter of the UK COVID-19 epidemic. The first COVID-19-positive cancer patient was reported on 29 February, 2020. Until 30 April, 2020, a COVID-19 swab was ordered for cancer patients with symptoms necessitating hospitalization or if they were scheduled to undergo a cancer-related treatment. From 1 May, 2020, COVID-19 testing was introduced as standard of care, with about 25% of patients being swabbed daily depending upon staff and testing kit availability. We analyzed data from 7-15 May, 2020 for COVID-19 test results in all cancer patients at our Centre.

Results: 2,647 patients attended for outpatient, chemotherapy, or radiotherapy appointments from across South East London (and England). Of these, 654 were swabbed for COVID-19 (25%). Over 57% of patients filled out a symptom assessment, and 97% were asymptomatic. Of the patients tested, nine were positive for COVID-19 (1.38%) of whom seven were asymptomatic. Based on data from the Office for National Statistics, between 28 April-10 May, 2020, 0.27% of the community population had COVID-19 (95%CI: 0.17-0.41). However, for those working in patient-facing health care or resident-facing social care roles, this was estimated at 1.33% (95CI%: 0.39-3.28). Nevertheless, London has been the region hardest hit by COVID-19, so the rate of 1.38% among asymptomatic cancer patients, the majority of whom will have been shielding, is likely to be more representative of the local situation. However, this “snapshot” of prevalence is not enough for an evolving situation.

Conclusion: Cancer service providers will need to understand their local cancer population prevalence and keep this under regular review. The absolute priority is that cancer patients have the confidence to attend hospitals and be reassured that they will be treated in a COVID-19-managed environment.

Citation Format: Charlotte Moss, Beth Russell, Mary Lei, Sharmista Ghosh, Sophie Papa, Richard Sullivan, Mieke Van Hemelrijck, Anne Rigg, Guy's Cancer Real World Evidence Programme. One piece of the jigsaw for the cancer recovery strategy: Prevalence of COVID-19 in patients with cancer [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr PO-028.