Table 2. Summary data of the studies about seroprevalence in oncological cohorts.

Sample size	Demographic and clinical variables: percentage (%) receiving active oncological therapy, treatment modalities	Date (month/year); place	Seroprevalence (%)	Surrogate for immunogenicity for COVID-19	Seroprevalence significantly different among different treatment modalities (CT and IT)	Authors
1,500	Only lung cancer patients in the outpatient setting. Active cancer treatment (>75%), CT (35.6%), IT (35.7%)	04/2020–6/2020 and 09/2020–11/2020; Madrid, Spain	8.5%	Anti-N IgG	No	Provencio et al. (6)
229	Solid cancers, active cancer treatment (59.8%), CT (25.8%), 18.8% hormone therapy, IT (4.3%) and TT (10.9%)	06/2020; Madrid, Spain	31.4% (IgG/IgM combined), 27.9% (only IgG)	Anti-S IgG/IgM	No	Gabezón-Gutiérrez et al. (16)
146 subjects (62 HCW and 84 patients with cancer)	All cancers including solid and hem malignancies. Active cancer treatment (96.4%), CT (31%), IT (27.4%), TT + CT (13.1%), TT + IT (3.6%)	03/2020 and 06/2020; Vienna, Austria	3.6% (patients), 3.2% (HCWs)	Anti-N IgM/IgG	NA	Fuereder et al. (18)
110	All cancers including solid and hem malignancies. Active cancer treatment (65%), CT (56%), IT (9%), TT (23%)	08/2020 and 02/2021; Germany	9%	Anti-N IgM/IgG	No	Overheu et al. (20)
1,674 subjects (663 staff members, 1,011 patients)	All cancers. Active cancer treatment (88.2%), TT (16.1%), CT (36%), IT (9%), CT + TT (9.9%), CT + IT (3.16%)	5/2020 and 06/2020; France	1.7% (patients), 1.8% (staff)	Anti-N IgM/IgG	NA	Ladoire et al. (19)
500 cancer patients, 1,190 HCW	Solid tumors (97.8%). Active cancer treatment (71%),CT (40.8%), IT (8.8%), TT (18.4%)	08/2020–10/2020; Japan	1% (patients), 0.67% (HCW)	Anti-N and anti-S IgM/IgG	Yes	Yazaki et al. (21)

Anti-N, anti-nucleocapsid antibody; anti-S, anti-spike antibody; CT, chemotherapy; IT, immunotherapy; TT, targeted therapy; HCW, health care workers; NA, not available.