SABCS 2010: Providing answers to long-held questions

The SABCS 2010 meeting may finally offer answers to questions that the breast cancer community has pondered for some time: 

•Do the subtle differences in the mechanism of action of third-generation aromatase inhibitors make a difference in clinical responses for women with estrogen-rich cancer? 

•Should bisphosphonates be adopted as part of standard adjuvant treatment?

•To what degree will the growing obesity epidemic play out in breast cancer in the future?

Oncology NEWS International spoke with SABCS codirector C. Kent Osborne, MD, about what to watch for at this year’s meeting. He highlighted the following key studies:

Thursday

General Session 1
ACOSCOG Z1031: A randomized neoadjuvant comparison between letrozole (Femara), anastrozole (Arimidex), and exemestane (Aromasin) for postmenopausal women with ER-rich stage II/III breast cancer: Biomarker outcomes and the predictive value of the baseline PAM50-based intrinsic subtype (abstract S1-2).

“We know about some subtle differences in the lab among letrozole, anastrozole, and exemestane, but many people are skeptical of whether those translate into any meaningful differences in clinical response,” explained Dr. Osborne, who also serves as director of the Dan L. Duncan Cancer Center, Baylor College of Medicine in Houston. “So this study may start to shed some light on whether there are any differences.”

Friday

General Session 2
First results of the NeoALTTO trial (BIG 01-06/EGF 106903): A phase III, randomized, open-label neoadjuvant study of lapatinib (Tykerb), trastuzumab (Herceptin), and a combination of the two plus paclitaxel (Taxol) in women with HER2-positive primary breast cancer (abstract S3-3).

“This will be a very hot paper,” Dr. Osborne said. The results will reveal whether the hypothesis of the study-that the combination of lapatinib and trastuzumab plus chemotherapy over either agent alone plus chemotherapy offers superior efficacy-is true.

General Session 4
Adjuvant treatment with zoledronic acid in stage II/II breast cancer. The AZURE Trial [(BIG 01/04); abstract S4-5).

The results of the AZURE trial could determine whether bisphosphonates are adopted in the adjuvant treatment of breast cancer, Dr. Osborne said. “Last year, a trial on premenopausal women was presented showing a fairly striking improvement in disease-free survival in patients with metastatic breast cancer treated with one of the bisphosphonates,” he said. “If this study shows the same thing, I’m sure these drugs will be adopted in the adjuvant treatment of breast cancer patients.”

Along with these individual studies, Dr. Osborne discussed some more general sessions that will be of particular interest at the SABCS 2010 meeting.

Thursday’s Clinical Science Forum will address the continuing controversy over breast cancer screening. During General Session 4 on Friday, data will be presented on obesity and cancer risk.

“We’ve known for decades that obese women are at higher risk of breast cancer and more recent data show obese women have worse prognoses if they do get breast cancer and that they don’t respond as well to certain kinds of therapy,” Dr. Osborne said.

Future challenges breast cancer specialists face include the mechanisms of resistance to certain treatments, such as the HER2-targeted therapies. “We know that in the adjuvant setting, hormonal therapy reduces the risk of recurrence by half, but that means about 40% of patients will recur and die,” he said. “How do the cells become resistant to these therapies, and how can we overcome resistance therapeutically?”

Another big challenge is advancing treatment for triple-negative breast cancer. “Right now we don’t have any targets for this disease other than the poly (ADP-ribose) polymerase (PARP) inhibitors, which really are not targeted therapies, “ Dr. Osborne said. “We are getting closer to being able to select patients among the triple-negative group who will respond to the PARP inhibitors, but we are not there yet.”

SABCS 2010 is sponsored by the AACR, the Cancer Therapy & Research Center (CTRC) at the University of Texas Health Science Center San Antonio, and the Baylor College of Medicine.