New research suggests that targeted therapies can be used to manage malignant phyllodes tumors (MPTs), a rare tumor of the breast with aggressive biologic behavior and high recurrence rates.

Duke Cancer Institute breast oncology program members Rani Bansal, MD, and Laura Rosenberger, MD, MS, worked together on this research published in JCO Precision Oncology. Bansal is a medical oncologist, and Rosenberger is a surgical oncologist.

MPTs are a type of growth that involves fibrous tissue and surface epithelium. Surgery is the primary treatment option for these tumors; however, Bansal and Rosenberger’s research assessed the molecular structure to reveal new possible treatment opportunities.

Study participants underwent genomic sequencing, whole-transcriptome sequencing, and immunochemistry to identify pathogenic fusions to determine potential targeted treatment options. Bansal said this revealed that participants showed prolonged benefit from targeted therapy, with some being able to stay on one targeted therapy for longer than one year.

While there are currently many drugs with approval from the Food and Drug Administration (FDA) across various tumor types, such as trastuzumab deruxtecan (T-DXd) for HER2-positive or HER2-low tumors, Bansal believes more options will be available soon.

“As the treatment landscape for oncology continues to expand, we will see more targeted therapies available for patients, and we can personalize their systemic treatment to their specific cancer,” she said.

While surgical resection remains the mainstay for treating MPTs, this research shows further investigation into how to incorporate targeted therapies into treatment plans is warranted. Bansal and Rosenberger are currently looking into clinical trials to continue this examination.

“These results will certainly guide clinical trial design and options for those with specific mutations,” Rosenberger said.

This research marks an important first step in understanding next-generation sequencing in MPTs and, hopefully, developing more targeted and effective treatment options for patients.

“As we continue to collect data on phyllodes tumors I think continuing to investigate this rare tumor group with more samples and correlating with clinical outcomes could lead to potential therapeutic advances,” Bansal said. “This is just the beginning, and our data shows clinical utility for sending next-generation sequencing for these tumors.”