Expectations and fears about chemotherapy and radiotherapy in patients with oncological illness may not only affect their subjective well-being (Shaverdian et al., 2018) but also treatment satisfaction and complaints of side effects (Guidolin et al., 2018, Dong et al., 2014, Colagiuri et al., 2013).

The aim was to compare beliefs about treatment in patients referred to radiation therapy and chemotherapy, and to reveal their relationship to health anxiety and subjective well-being.

53 patients referred to radiation therapy and 63 patients referred to chemotherapy completed the Treatment Perception in Oncological Illnesses Scale (Kovyazina et al., 2021), Illness and Treatment Self-Regulation Questionnaire (Kovyazina et al., 2019), Satisfaction with Life Scale (Diener et al., 1985) and Scale of Positive and Negative Experiences (Diener et al., 2009).

Compared to radiation therapy, with chemotherapy, patients tend to be more doubtful about the effectiveness of treatment and more anxious about the need for it (p<.05). Moderated mediation analysis demonstrated that lack of understanding, doubts about the effectiveness and anxiety about radiation and chemotherapy are associated with subjective ill-being indirectly - through a higher level of health anxiety (β=-.79--.35, SE=.17-.26, 95% CI [-1.42 - -.75 – -.37 - -0,08]). Feelings of helplessness regarding treatment mediated the relationship between doubts and confidence about treatment effectiveness and well-being in both groups.

Results demonstrated that some fears and expectations about chemo- and radiotherapy could provoke health anxiety and helplessness regarding treatment that is related to poorer well-being.

No significant relationships.