Introduction: emotional and physical alterations frequently appear in cancer patients. In this sense, interventions based on acceptance and commitment therapy (ACT) show their efficacy to improve these symptoms through increased psychological flexibility, however, there is little evidence of the efficacy of ACT using combined modality (face-to-face + app), despite the fact that this application modality may have beneficial effects in this group of patients, who may see their participation in the interventions limited as a consequence of the disease. Method / design: Cancer patients will be randomly assigned to one of the following groups: (1) face-to-face ACT + app group, (2) face-to-face ACT group, and (3) group receiving usual treatment. The planned interventions last between 8 and 10 weeks and include experiential exercises, metaphors, discussions, and homework assignments to promote awareness and flexibility about thoughts and emotions associated with cancer. In the group that uses the app, exercises (mindfulness, breathing), reminder systems, recording, reinforcement and monitoring will also be provided. It is estimated that a total of 112 participants (38 per group) will be necessary, and four evaluations will be carried out: T0 (pre-treatment), T1 (post-treatment, T2 (follow-up at three months) and T3 (follow-up at six months). months). Hypothesis : The primary results that are expected to be obtained are a significant increase in the psychological flexibility of patients receiving treatment, with greater flexibility in the group receiving the combined intervention, evaluated with the AAQ-II. Furthermore, as secondary outcomes, it is expected to obtain significant improvements in anxiety and depression (HADS), quality of life (EORTC QLQ C-30), Fatigue (BFI), Insomnia (ISI) and post-traumatic growth (PTGI-SF). Hypothesis: the efficacy of the ACT-based intervention in cancer patients may be increased if the benefits of using a modality that combines face-to-face and not face-to-face are added to it.