Based on the work you do at the Cleveland Clinic Taussig Cancer Institute, what is your standard approach to managing early stage cancer patients?
Dr. Roesch: The approach to managing patients with early stage breast cancer very much depends on the subtype of breast cancer. Clinical stage at presentation and patient factors are considered here. For example, patients with small hormone receptor-positive tumors will often have surgery first, while patients with triple-negative or HER2-positive tumors will often receive preoperative or neoadjuvant chemotherapy.
In situations where there is a need or a desire for downstaging or shrinking of the primary tumor or lymph nodes in the axilla, we will also discuss neoadjuvant systemic therapy. For hormone receptor-positive tumors, endocrine or anti-estrogen therapy will be incorporated into their treatment regimen at some point in the future.
The role of chemotherapy for hormone receptor-positive breast cancer depends on a variety of factors, including pathologic staging, which we obtain at the time of surgery. Exceptions may include very small tumors or patients who have medical comorbidities that affect their candidacy for chemotherapy where the risk may outweigh the benefit.
Are there specific steps you take in managing and treating early stage triple-negative breast cancer?
Dr. Roesch: Most patients with early stage triple-negative breast cancer receive neoadjuvant or preoperative chemotherapy. As I mentioned above, this has the benefits of downstaging the primary tumor itself and the lymph nodes in the axilla as well as providing prognostic information. This approach can also help guide adjuvant therapy recommendations. Additionally, we often discuss the role of genetic counseling for these patients.
Are there targeted therapies you rely upon?
Dr. Roesch: This has been an evolving field with dramatic advances in the past couple of years. One is immunotherapy. There was a phase III study called the KEYONTE-522 trial, which demonstrated improvements in pathologic response rate and event-free survival with a regimen of neoadjuvant pembrolizumab plus chemotherapy followed by the pembrolizumab given in the adjuvant setting, compared to chemotherapy approach alone (1).
For patients who meet criteria for this study, which is essentially stage II/III triple-negative breast cancer, we have adopted this regimen in the neoadjuvant setting. Additionally, we consider adjuvant capecitabine for patients who have received neoadjuvant chemotherapy with an anthracycline, taxane or both and who have residual disease at the time of surgery. This is based on the CREATE-X trial, which showed a survival benefit for patients with triple-negative breast cancer in this situation (2).
Lastly, the PARP inhibitor, olaparib, was recently approved by the FDA in the adjuvant setting for BRCA mutation carriers diagnosed with HER-2-negative high-risk early breast cancer who have received neoadjuvant or adjuvant chemotherapy. This treatment also demonstrated survival benefit and is an exciting new option for these patients (3).
A critical question in my mind that has arisen out of these new developments is sequencing of these therapies. For example, if I have a patient who received the KEYNOTE-522 regimen with the immunotherapy agent, pembrolizumab, and has residual disease after surgery, how do we administer the capecitabine with the pembrolizumab? And what about radiation? What if a patient is a BRCA mutation carrier? These are all very relevant questions, which we are encountering every day, and the approach we take is often individualized.
This sounds very exciting. Can you talk about the research on managing early triple-negative breast cancer and what the future might hold?
Dr. Roesch: This is a very exciting time for both us as oncologists and our patients as there is a very rapid pace of new therapies being explored in the context of clinical trials. First, I'd like to mention the adjuvant vaccine trial we have at Cleveland Clinic for patients diagnosed with early stage triple-negative breast cancer at high risk of recurrence. This trial is investigating an alpha lactalbumin vaccine, which has been selected as a vaccine target because it is a breast-specific differentiation protein expressed at high levels in many human breast cancers, particularly in triple-negative breast cancer. The current trial's main objective is to determine the maximum tolerated dose of the vaccine, and other endpoints include looking at biomarkers of immune responses (4).
The I-SPY2 trial is another very exciting study we have open at Cleveland Clinic. This is a multicenter phase II trial using response adaptive randomization within molecular subtypes, which is defined by the receptor status and MammaPrint risk, which is a genomic assay, to evaluate novel agents as neoadjuvant therapy for women with high-risk breast cancer. Patients undergo serial MRIs and biopsies with information on the likelihood of them achieving a pathologic complete response (pCR) provided back in real time, which will then allow for therapy escalation or de-escalation. The goal here is individualized precision therapy based on the specific intrinsic subtype of the tumor itself and response with the ultimate goal being to achieve a pCR (5).
Again, this is a very exciting time for us as medical providers and our patients because new therapies are being developed and studied in clinical trials every day.