The implementation of lockdowns and other mobility restrictions following the onset of the coronavirus disease 2019 (COVID-19) pandemic has affected cancer care delivery, as shown by multiple studies. However, research suggests that restoration of cancer care is possible, but only if viral spread is contained.
A new preprint on the medRxiv* server describes how a successful application of mitigation techniques to prevent COVID-19 transmission to cancer patients admitted to or attending a healthcare facility might look.
Cancer care dilemma
Cancer patients have a higher risk for adverse outcomes following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pathogen of COVID-19.
In order to prevent such infection in this subset of patients, many care procedures targeting cancer patients have been either modified or postponed during the current pandemic. The consequences are likely to be an excess of almost 10,000 deaths over the expected number over the next ten years from breast and colorectal cancer alone.
The decision faced by both cancer patients and their healthcare providers is whether to continue attending their treatment centers for direct care to treat or prevent cancer or relapses, or to postpone treatment to reduce the risk of COVID-19. The key, says the current study, is the adoption of intensive transmission containment strategies at both the community and health center level.
The current study compares COVID-19 incidences following two distinct paths of patient care: one switching to virtual visits, chemotherapy at home, and longer intervals between successive infusions; and the other with in-person care, accompanied by text messages enquiring about contact with COVID-19 positives, temperature screening, contactless procedures for checking into the center, limitations on visitors, and setting up physical barriers within COVID-19 clinics.
The researchers conducted a prospective study on the rates of seropositivity for SARS-CoV-2 antibodies, and seroconversion, within a group of 124 patients on cancer treatment. All participants had solid tumors and were admitted between May 21 and August 10, 2020. All patients were tested for seropositivity on the same day – both to obtain a mix of solid cancers and to allow proper follow-up over time.
Patients were tested for seroconversion up to five times, at least three weeks ensuing between successive samples. Other variables included self-reported health, exposure to the virus, and social interactions. All antibody tests were done using an enzyme-linked immunosorbent assay (ELISA) that was both highly sensitive and specific.
High compliance, low seropositivity
Most of the patients had metastatic cancer, and had received a median of two lines of chemotherapy already. During the study period, they had a median of 13 in-person visits to the healthcare center, and seven therapy cycles. Almost 95% of the patients said they followed social distancing as recommended by the US Centers for Disease Prevention and Control (CDC), and almost 70% said they had few social interactions, with three or fewer trips out of their home every week.
Of the 78 patients who completed a second survey, almost 60% continued to report few social interactions, while almost one in five said they had now reduced their interactions to three or less per week. The patients denied any history of exposure in 85% of cases in both surveys.
At least 90 had a repeat blood sample taken at least four weeks from the first. Seropositivity was detected in only two 1.6%) participants in the first round, both being white women with metastatic cancer, on chemotherapy. With repeated blood draws, no seroconversion was observed. The seroconversion rate with two rounds of testing is thus nil over ~15 person-years, with a median of 13 visits per patient.
What are the implications?
These results suggest that cancer patients receiving in-person care at a facility with aggressive mitigation efforts have an extremely low likelihood of COVID-19 infection.”
The researchers point out that it is impossible to assign a causal role to mitigation techniques with respect to a low seroconversion rate, firstly because patients with mild COVID-19 may have low antibody titers, as well as patients on immunosuppressive therapy. Secondly, seroprevalence depends on many individual, geographic, and temporal factors.
Nonetheless, the low seropositivity and seroconversion may reflect both the high compliance rate with COVID-19 prevention strategies, and the successful containment of transmission in healthcare facilities, both operating simultaneously to prevent the infection in this vulnerable patient segment. It is noteworthy that viral spread was contained even as immunomodulatory treatments continued and patients found it necessary to visit healthcare centers repeatedly. As the pandemic drags on, it will become increasingly necessary to strengthen adherence to social distancing and other preventive practices.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.