Dyspnoea and functional decline are common among cancer patients with associated respiratory conditions. This study aimed to evaluate the effectiveness of an Effort Re-education Programme (ERP) in improving functionality and quality of life in hospitalised oncology patients compared to Conventional Clinical Practice (CCP). A stratified, randomised, prospective clinical trial was conducted involving 65 patients with cancer and associated respiratory conditions. Participants were assigned to either a control group (CCP) or an experimental group (ERP + CCP). Functionality (Barthel Index), health-related quality of life (EORTC QLQ-C30), overall performance (Karnofsky Scale), and instrumental activities of daily living (Lawton and Brody Scale) were assessed at baseline and one month post-discharge. The ERP group showed significantly greater improvements in all outcome measures: Barthel Index (mean change: +18.33 vs. +6.19), EORTC QLQ-C30 (+16.4 vs. +6.6), Karnofsky (+18.75 vs. +5.6), and Lawton-Brody (+2.78 vs. +0.78), all with < 0.001 and moderate-to-large effect sizes (Cohen's d = 0.72-1.19). No readmissions were reported in the ERP group, versus 37.5% in the control group. The ERP significantly improves basic and instrumental functionality, autonomy, and health-related quality of life in oncology patients with respiratory conditions. These findings support the integration of Functional Re-education Programmes into routine clinical practice as a complement to standard care.