Breast Cancer "Practice Changers" From San Antonio and ASCO

Rapid advances in the prevention, diagnosis and treatment of breast cancer keep clinicians on their toes. And this last year offered no reprieve, according to Debu Tripathy, MD, who highlighted several recent shifts and refinements to practice in his talk at the Miami Breast Cancer Conference.

Debu Tripathy, MD

Dr. Tripathy focused on developments presented at the recent San Antonio Breast Cancer Symposium (SABCS) and the American Society of Clinical Oncology (ASCO) annual meeting that surgeons and clinical oncologists can apply today-from new strategies for handling sentinel node and genetic data to identifying when radiation therapy might be skipped.

"There are some totally new findings, some findings that go against what we previously thought, and some extensions of what we already know," Dr. Tripathy, co-leader of the Women's Cancer Program at the University of Southern California and Norris Comprehensive Cancer Center in Los Angeles, told CancerNetwork prior to the conference.

Preliminary results from one recent trial (ASCO abstract CRA 504), for example, suggested that the presence of immunohistochemistry (IHC) positive sentinel lymph nodes does not impact recurrence or survival. IHC positive status in bone marrow, however, reduced survival at 5 years compared to patients with IHC negative bone marrow (90% versus 95%, P = .01).

"We really do not need to perform IHC on sentinel lymph nodes," Dr. Tripathy told the Miami crowd. "Of course, even at my institution it's been hard to give up."

Current data may also quiet other common practices. CYP2D6 genotype testing showed no prognostic power (SABCS abstract S1-8), and the removal of sentinel lymph nodes alone proved just as effective as axillary node dissection for certain groups of patients (ASCO abstracts CRA 506 and LBA 505).

Further, new evidence hinted that radiation added to tamoxifen does not affect the development of distant metastases for patients aged 70 and older with hormone receptor positive cancer (ASCO abstract 507). More ipsilateral recurrences did occur in older women treated with tamoxifen alone, however (9% versus 2%, P = .0001).

As for what might be added to a clinician's arsenal, one new study (ASCO abstract CRA1005) found that the chemotherapy drug eribulin alone extended median survival by about two and a half months compared to a treatment of the physician's choice for women with heavily-treated metastatic breast cancer (P = .04).

Helping patients optimize their energy balance through diet and exercise is also key, according to Dr. Tripathy. New data bolsters the idea that obesity affects breast cancer progression (ASCO abstract 512)-likely due to the interaction of estrogen and insulin-as patients with a body mass index of 25 or greater had triple the risk of death compared to their lighter weight peers (P = .004). Risks were particularly high for overweight or obese women treated with aromatase inhibitors.

The list of recent developments goes on, including the benefits of PARP inhibitors in triple negative breast cancer (ASCO abstract 3002), molecular and clinicopathological data in decision-making (ASCO abstract 509) and dual HER2 blockades (SABCS abstracts S3-2 and S3-3).

While these last findings may not yet be "ready for prime time," said Dr. Tripathy, they could "change the research or clinical landscape soon."