Background: The aim of the CARE for CAYA-program (CFC-P) was to implement a multimodal lifestyle program in addition to medical follow-up care for child, adolescents and young adult cancer survivors (CAYAs). Methods: The CFC-P was a multicenter program with an initial randomized clinical trial (RCT) comparing need-based modular interventions to usual care for CAYAs aged between 15 and 39. A comprehensive assessment (questionnaires and medical examination) was conducted to determine individual needs regarding nutrition, physical activity and psycho-oncology. If “high need” was identified, CAYAs could take part in up to three modules over 12 months. In the intervention group (IG), each module included five consultations plus newsletters. The control group (CG) included one baseline counseling in each module. The primary outcome was defined as the rate of CAYAs with “high need(s)” after 12 months of intervention. Secondary outcomes included feasibility, cost-effectiveness, modular-specific endpoints, quality of life (QoL) and fatigue. Results: 791 CAYAs were included at 14 German CAYA survivorship clinics from December 2017 to March 2021. Most common tumor types were lymphoma 26.8% (n = 211), sarcoma 13.2% (n = 104) and leukemia 10.0% (n = 79). 58.0% (n = 457) were female, median age was 23.9 years, time since end of tumor specific therapy was < 5 years in 54.4%, > 5 years in 21.2%, > 10 years in 11.5% and > 15 years in 12.9% of patients (median: 57.0 months). 86.2% (n = 679) reported an initial “high need” in at least one module. After 52 weeks, 83.9% (n = 396 of 472 evaluable participants) continued to report or developed a “high need”: 59.3% (n = 235) in IG and non-randomized cohort, 28.8% (n = 114) in CG and 12.7% (n = 47) with no initial “high need”. 357 participants were evaluable in the RCT (63% (n = 226) female, median age 25.0 years). 26.2% (n = 94) reported a “high need” in one, 35.7% (n = 128) in two and 37.6% (n = 135) in three modules. 271 patients could be analyzed at 52 weeks, 87.0% of IG (n = 120 of 138) and 86.5% of CG (n = 115 of 133) continued to have at least one “high need”. The primary outcome did not differ significantly between groups (p = .905). However, both showed an increase of QoL and a reduction of fatigue. Conclusions: In the CFC-P, the feasibility of a large trial to regularly assess lifestyle habits and the psychosocial situation and determine the efficacy of a need based multimodal interventions in CAYAs was demonstrated. Although a high need for support was revealed in this population, no significant changes with the applied interventions were noted after 12 months. The obtained data will guide the development and implementation of multimodal interventions in long term follow up of CAYAs. Clinical trial information: DRKS00012504.