There are many gaps and interesting hypotheses related to breast cancer patients' body composition, dietary intake, energy metabolism, potential biomarkers, feasible and beneficial dietary strategies you could study.
A few years ago we published a review that describes some of these ideas better. In case you are interested in reading it, you can access using the following link: https://academic.oup.com/advances/article/8/4/613/4558106#.YBCB2vTX_mY.link