Background <p>There is a need for interdisciplinary primary care-led aftercare programs for the common (transdiagnostic) problems cancer survivors experience to increase their quality of life. The aim of this before-and-after (pre-post) pilot study was to examine the feasibility and preliminary effectiveness of a transdiagnostic, family doctor-led interdisciplinary program to increase quality of life in a heterogeneous group of cancer survivors.</p> Methods <p>Cancer survivors (<i>n</i> = 19) followed a 12-month interdisciplinary aftercare program in the primary care setting, consisting of: family doctor consultation, exercise, mind-body therapy, sleep hygiene, nutrition recommendations, and optional psychological therapy. Eligible cancer survivors who declined participation, were recruited as controls (<i>n</i> = 16). Feasibility and acceptance were assessed through attendance and attrition rates, and an evaluation form. The primary outcome was the change in quality of life from baseline (T0) to post-intervention (T2; 12 months from baseline), as measured with the EORTC QOL-C30, covering global health status, various functional domains, and symptoms. Secondary outcomes included assessments of changes in fatigue (Multidimensional Fatigue Inventory), psychological symptoms (Depression, Anxiety and Stress scale), happiness (Happiness Index), and work ability (Work Ability Index). Intention-to-treat multilevel analyses were conducted.</p> Results <p>Dropout (<i>n</i> = 3) during the program was related to personal and health issues, and attendance rates and satisfaction scores were satisfactory. At baseline, the intervention group scored significantly worse on several quality-of-life indices, and on secondary outcomes, compared to controls. The intervention group showed significantly larger increases at T2 in physical and social functioning, and decreases in fatigue and anxiety, compared to the control group.</p> Conclusions <p>The results suggest that this primary care-led aftercare program is feasible and acceptable. Due to the small sample size and non-randomized design, improvements in quality of life and related outcomes should be interpreted with caution. A randomized controlled trial is warranted.</p> Trial registration <p>This study was retrospectively registered at clinicaltrials.gov (NCT06809452).</p>