During the COVID-19 pandemic, cancer patients became reluctant to come to the hospital, receive cancer treatment, and were willing to interrupt or postpone treatment due to concerns about infection. The purpose of this study was to discuss effective treatment strategy decision making support for cancer patients by nurses recognized during the COVID-19 pandemic. The study population comprised nurse of decision-making support at cancer care during COVID-19 from May to July 2021 at 49 the cancer care center hospitals were established in each prefecture, who had engaged 50% of their nursing care provided to patients with cancer.Data were collected on treatment strategy decision-making support using an online cross-sectional survey. Factors that influenced patients’ decision-making were identified using multivariable logistic regression analysis. A total of 182 (25.0%) were nurses engaged in decision making were enrolled in this study. Factors that influenced patients’ decision to receive treatment to their satisfaction were their resignation or compromise in accepting the decision due to the pandemic (odds ratio [OR] 0.44 (95% CI [0.22, 0.87]), videoconference follow-up (OR 0.17, 95% Cl [0.04, 0.66]), and infection prevention information provision (OR 3.82, 95% Cl [1.54,9.46]). Factors influencing patients’ decision to give up and accept the doctor’s recommendation even though they were not convinced included fear of disease progression (OR 2.51, 95% Cl [1.21, 5.22]), anger at not receiving the treatment they desired (OR 2.48, 95% Cl [1.17, 5.27]), and compromise with the pandemic situation (OR 3.15, 95% Cl [1.53, 6.50]). The factor that influenced patients’ continued treatment even though they were not convinced included the nurse listened to the patients’ thoughts (OR 0.07, 95% Cl [0.01, 0.51]). Treatment decision support of patients with cancer during COVID-19 included lifestyle guidance to prevent the spread of infection and listening to their concerns to help them find meaning in their choices.