"If only I had", patients' experiences during early oncology trials.

Purpose: Until today, it is not clear why patients decide to continue with early clinical trial (ECT) participation. Therefore, the aim of this study is to explore to which extent the self-determination theory of Ryan and Deci, according to the ECT enrollment phase, corresponds to the motivations of participants during ECT's.

Methods: This study has a qualitative design. Data were collected using semistructured interviews and were deductively analyzed in Nvivo12 using the thematic analysis approach of Braun and Clarke.

Results: As a result of the deductive analysis performed, six themes and twenty subthemes emerged which matched the three personal needs: competence, relatedness, and autonomy (n = 11). "Competence" included the following themes: mixed future expectations, treatment expectations, and control of the outcome. "Relatedness" included the theme altruistic motivation. "Autonomy" included the themes; to live and act in harmony as well as mental and physical burden.

Conclusion: Participants felt they tried everything and that they were treated to the limit. This not only gives the motivation to continue participating but also a sense of altruism. Despite different burdens, side-effects, and the feeling of being a test subject, the participants will not easily choose to stop participation in order to prevent saying afterwards: "If only I had".