KEY TAKEAWAYS
- The phase 3 DATA trial was conducted in postmenopausal HR+ breast cancer patients to determine the effect of BMI on DFS in individuals who underwent (extended) endocrine therapy.
- The study found that in HR+ breast cancer pts younger than 60 years old, being overweight or obese had an adverse effect on DFS.
- Extended anastrozole did not show any significant difference in its effect on adjusted DFS between different BMI classes.
In the phase 3 DATA trial, the impact of body mass index (BMI) on disease-free survival (DFS) in postmenopausal hormone receptor-positive (HR+) breast cancer patients (pts) who underwent (extended) endocrine therapy was analyzed to determine its prognostic and predictive effects.
The study randomized pts with HR+ breast cancer who had completed two to three years of adjuvant tamoxifen and had a BMI of ≥18.5 kg/m2. They were categorized based on their weight as average weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), or obese (≥30 kg/m2). The study evaluated six versus three years of anastrozole use in disease-free postmenopausal women. The primary endpoint was DFS. Multivariable Cox regression analyses were conducted. BMI’s prognostic impact was assessed from the randomization date. In contrast, its predictive effect on the efficacy of extended anastrozole was evaluated three years after randomization, i.e., treatment divergence (adapted DFS).
The study included 1,781 pts with 678 average weight, 712 overweight, and 391 obese. Results demonstrated that overweight and obese pts had worse disease-free survival rates after 13.1 years than normal-weight pts (hazard ratio (HR)=1.16; 95% confidence interval (CI) 0.97-1.38, p=0.10; and HR=1.26; 95% CI 1.03-1.54, p=0.03, respectively). Being overweight or obese negatively affects DFS for women under 60 (HR=1.29; 95% CI 1.00-1.67, p=0.05), as was obesity (HR=1.83; 95% CI 1.36-2.46, p<0.001), but not for those aged 60 and above (HR=1.04; 95% CI 0.82-1.33, p=0.72; and HR=0.94; 95% CI 0.72-1.23, p=0.63, respectively) (p-interaction = 0.009). Anastrozole had similar effects on DFS for pts of different weights. (HR=1.00; 95% CI 0.74-1.35, p=1.00), overweight (HR=0.74; 95% CI 0.56-0.98, p=0.04), and obese pts (HR=0.97; 95% CI 0.69-1.36, p=0.85) (p-interaction=0.24).
The study reported that being overweight or obese can harm the DFS of HR+ breast cancer pts under 60, but not those 60 or older. Prolonged use of anastrozole didn’t affect outcomes based on BMI.
Clinical Trial: https://classic.clinicaltrials.gov/ct2/show/NCT00301457
Lammers, S., Geurts, S., van Hellemond, I.E.G., Swinkels, A.C.P., Smorenburg, C.H., van der Sangen, M., Kroep, J.R., de Graaf, H., Honkoop, A.H., Erdkamp, F.L.G., de Roos, W.K., Linn, S.C., Imholz, A.L.T., Smidt, M.M., Vriens, I.J.H., Tjan-Heijnen, V.C.G. Annals of Oncology (2023) 8 (1suppl_4): 101219-101219. 10.1016/esmoop/esmoop101219.
