Purpose: Motivation to treat cancer and prevent its negative impact has been largely explored in a non-pandemic context. However, little is known about the motivation to comply with the treatment, especially during a pandemic. To fill this gap, we have explored the individual and contextual factors impacting patients' motivation during the COVID-19 period using the integrated model. Methods: We have conducted two qualitative studies before (study 1) and during the COVID-19 (study 2) period in a cancer centre. We respectively interviewed 30 and 22 patients with various chronic cancers in study 1 and also with COVID-19 in study 2. Data analysis was based on content analysis and grounded theory approach identifying the factors affecting patient motivations during both periods, and then comparing them. Results: Our results show the mechanisms that allow patients to maintain their motivation despite the threats related to COVID-19. They underline the importance of respecting the rules and laws for patients' motivation. Conclusion: Compliance with legislation fuels the psychological need of protection in patients, which is a key determinant of motivation in the context of the pandemic. Considering patients' self-regulatory activities to assess motivational factors, going beyond clinical aspects, to include organisational and quality-of-life-related aspects throughout their care pathway is crucial.