Impact of treatment delay due to the pandemic of COVID-19 on the efficacy of immunotherapy in head and neck cancer patients

Immunotherapy has been a new standard for recurrent/metastatic head and neck cancers (R/M HNC). One of the prominent characteristics of cancer immunotherapy is the induction of immune memory followed by endured treatment response. However, whether and how a treatment delay would impact on the efficacy of immunotherapy has not been well determined. During the outbreak of COVID-19, a number of cancer patients in Wuhan, the epicenter of the pandemic in China, had experienced long-lasting city lockdown and delay of immunotherapies. Here, we retrospectively analyzed 24 HNC patients treated with immune checkpoint inhibitors in our cancer institute prior to the outbreak of COVID-19 who were re-evaluated after the restoration of regular medical care. Of these 24 patients, 10 patients had achieved complete response (CR) or partial response (PR), 12 patients had achieved stable disease (SD), and 2 patients had received just one cycle treatment without efficacy evaluation before treatment delay. The median delay was 3.75 months (range 1.73-8.17 months). Re-evaluation after treatment delay revealed that ten patients (10/10) who achieved CR or PR, two patients (2/2) who received just one cycle treatment without efficacy evaluation and seven patients (7/12) who achieved SD before outbreak of COVID-19 maintained tumor response after treatment delay. Among the rest five patients who had achieved SD, four patients were re-evaluated as progressive disease (PD) due to treatment delay and one patient died after treatment interruption without re-evaluation. Our results from a small cohort of R/M HNC patients showed that treatment delay of three to four months might have mild, if any, impact on the efficacy of immunotherapy for patients with controlled disease.