Simple SummaryPersistent impairments in quality of life, particularly in cancer-associated fatigue, are a major limitation for breast cancer survivors. As physical activity and mindfulness interventions have been shown to be effective, the question arose whether a supervised Argentine tango program may also reduce fatigue symptoms. Evaluation of the self-reported quality of life parameters revealed that quality of life, including fatigue, improved after six weekly one-hour tango sessions. The TANGO trial shows that an Argentine tango program may be an efficacious intervention to improve fatigue and quality of life in breast cancer survivors.AbstractBackground: Persistent impairments of quality of life—in particular, cancer-associated fatigue—are a major limitation for breast cancer survivors. As physical activity and mindfulness interventions have been shown to be effective in reducing fatigue symptoms, we investigated the efficacy of a six-week Argentine tango program. Methods: A randomized controlled trial was conducted with 60 breast cancer survivors diagnosed with stage I-III tumors 12–48 months prior to study enrollment and who had increased symptoms of fatigue. The participants were randomly assigned with a 1:1 allocation to either the tango or the waiting group. The treatment consisted of six weeks of supervised weekly one-hour tango group-sessions. Self-reported fatigue and further quality of life parameters were assessed at baseline and six weeks post-baseline. Longitudinal changes, correlations, Cohen’s D (d) effect sizes, and association factors were also calculated. Results: Superiority of the tango intervention over the waiting list control was found in terms of improvement in fatigue (d= −0.64; 95%CI, −1.2 to −0.08;p= 0.03), especially cognitive fatigue. In addition, a superiority of the tango intervention over the waiting list was found in the improvement of diarrhea (d= −0.69; 95%CI, −1.25 to −0.13;p= 0.02). A pooled pre-post analysis of the 50 participants completing the six-week tango program revealed a close to 10% improvement of fatigue (p= 0.0003), insomnia (p= 0.008) and further quality of life outcomes. Adjusted multivariate linear regression analyses revealed the greatest improvements for participants who were more active in sports. In particular, survivors who received endocrine therapies, were obese, or had no prior dance experience seemed to especially benefit from the tango program. Conclusions: This randomized controlled trial demonstrated that a six-week Argentine tango program improves fatigue in breast cancer survivors. Further trials are warranted to determine whether such improvements lead to better long-term clinical outcomes. Trial registration: trial registration number DRKS00021601. Retrospectively registered on 21 August 2020.