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Randomized Multicenter Phase II Study of Docosahexaenoic Acid (DHA) in Patients with a History of Breast Cancer, Premalignant Lesions, or Benign Breast Disease

Trial Summary

This phase II double blinded trial is designed to determine whether treatment with DHA reduces levels of tumor necrosis factor-alpha (TNF) in normal breast tissue in overweight and obese female patients with a history of breast cancer or DCIS, LCIS, Pagets Disease or benign proliferative breast disease as its primary endpoint. Additionally, the study investigates the effect of DHA on various tissue biomarkers and evaluates red blood cell (RBC) fatty acid levels as a surrogate of compliance as secondary endpoints.

Randomized trial with two arms:

  • Arm I: DHA (2 x 500mg capsules twice daily)
  • Arm II: Matched Placebo (2 capsules twice daily)

Target Randomizable Enrollment: 64

Target Evaluable Enrollment: 50

Statistical Analysis:

This randomized phase II trial was designed to enroll a total of 64 subjects to ensure a targeted 50 evaluable subjects after accounting for an expected 10% dropout rate and around 10% nonevaluable rate. Subjects were randomized at 1:1 ratio to each study arm using urn randomization stratified by study site. The primary objective was to determine whether treatment with DHA compared with placebo reduced normal breast tissue levels of TNF in overweight and obese patients meeting the study inclusion criteria. Assuming an expected 0.4 correlation between pre- and posttreatment biomarker levels, the planned sample size has 80% power to detect effect size as small as 0.74 in the adjusted TNF levels between the two arms at a two-sided 0.05 significance level using ANCOVA (37). This sample size also had 80% power at 0.05 significance level for an effect size as small as 0.58 for the post- minus pretreatment percent change in the biomarker level in the treatment arm using a paired two-sided t test.