The compelling findings of phentermine use are of paramount significance and could provide justification for clinical trials aimed at validating their efficacy as potential BrCa- and ECa-preventive strategies in older women with risk factors such as obesity, genetic alterations (e.g., BRCA1/2, Lynch syndrome), family history of cancer, and hormone replacement therapy use. This evidence concerns the gene BRCA1 and obesity due to melanocortin 4 receptor deficiency.