Personalized treatment in oncology is a popular concept these days, but the goal remains elusive when it comes to tailoring adjuvant chemotherapy to achieve maximal therapeutic benefit, according to William F. Symmans, MD, a professor of pathology at the MD Anderson Cancer Center in Houston, Texas.
“We’ve made marginal progress toward personalization of adjuvant chemotherapy,” Symmans said during a presentation at the Miami Breast Cancer Conference.
Such therapies hold the promise that clinicians can identify which treatments are futile, toxic, and expensive for a particular patient, thereby giving doctors the tools to assess the relative difference and absolute benefit between the treatment options.
Symmans said the best advance in targeted oncology in the breast cancer arena was the addition of trastuzumab (Herceptin) to chemotherapy for HER2-positive disease. However, he said, the chemotherapy component should be tailored to patients based on whether they would benefit from a regimen that includes an anthracycline.
“To date, there has been no clear indication from biomarker studies to guide this decision,” he said.
In addition, Symmans noted that there are no predictive tests to help guide decisions on whether the benefits of concurrent administration of trastuzumab and an anthracycline outweigh the risks of cardiotoxicity. As a result, Symmans noted, patient selection for this therapy remains “based on risk assessment from clinicopathologic factors.”
Other clinical situations where biomarker tests would be useful include whether topoisomerase 2 is a selective biomarker for anthracycline sensitivity, which could guide treatment decisions in HER2-negative breast cancers, and whether the basal-like subset of triple-negative breast cancer patients would benefit from platinum-containing chemotherapy.
“Unfortunately, this field struggles with determining the best clinical trial approaches to develop accurate and specific predictors to select among adjuvant chemotherapy regimens,” Symmans said.
Symmans believes that prospective randomized neoadjuvant trials of standardized chemotherapy regimens “hold the greatest promise for such approaches to discriminate between different regimens.”