Many cancer patients wish for complementary and integrative medicine (CIM) consultations led by their oncology physician. Within the KOKON-KTO study, oncology physicians in the intervention group were trained in a blended learning to provide CIM consultations to their cancer patients in addition to distributing a leaflet about CIM websites. Control oncology physicians only distributed the leaflet. The training showed positive effects on the patient-level. As of now, no consistent evidence exists on the long-term effects of such one-time-only CIM consultation during cancer treatment. In the KOKON-KTO follow-up study, cancer patients previously participating in the KOKON-KTO study (intervention group:IG and control group: CG) received, at least 24 months later, a follow-up questionnaire by post, evaluating long-term effects of the KOKON-KTO consultation using the measures provided in the original study (patient-physician communication (EORTC-QLQ-COMU2), satisfaction with cancer treatment (PS-CaTE), CIM disclosure with healthcare provider (HCP), and need for CIM consultation during cancer therapy). In total, 102 cancer patients participated in the follow-up study (IG n = 62; CG n = 40). The overall reponse rate was around 36% (IG: 48.4%; CG: 23.7%). In the follow-up study, differences between groups had increased and were still shown (EORTC-QLQ-COMU26, 0-100 point scale, ≥10-point-group difference) in some subscales: patient's active behavior (in means; IG:73.6 (95% CI, 63.8-83.5); CG:61.1 (95% CI, 52.4-69.8)); clinician-patient relationship (IG:80.9 (95% CI, 71.8-90.0); CG:68.7 (95% CI, 59.3-78.0)). For some outcomes, differences decreased over time (e.g., EORTC-QLQ-COMU26 subscales "takes into account patient's preference" and "corrects misunderstandings"). More patients in the CG used CIM without oncology physicians' knowledge (IG: 13.7%, CG: 24.0%). This study presents first findings that one-time-only CIM consultations may enhance patient-physican relationship and CIM disclosure long-term. To further support cancer patients' in their wish for CIM consultations, training programs should provide oncology physicians with CIM competencies for different cancer stages including cancer survivors.