San Antonio Breast Cancer Symposium (SABCS)

At this year’s San Antonio Breast Cancer Symposium, new data results from four different clinical trials of bisphosphonate usage in patients with breast cancer will be presented and discussed.

The San Antonio Breast Cancer Symposium brings together basic science researchers and clinicians for the latest breast cancer research-related progress. The symposium has evolved from a 1-day local conference to a 5-day international meeting focusing on clinical, preventive, diagnostic, translational, and basic research.

Cancer Network interviews Kent Osborne, who is the moderator of the year in review session. He has been involved with the meeting since its beginning. The international San Antonio Breast Cancer Symposium is unique as it facilitates the interaction of both basic and science researchers and clinicians to combine the efforts of laboratory research and clinical research for better treatment and patient care.

Ten-year follow-up results from the BCIRG 001 trial make a case for TAC therapy over FAC. In another study, researchers suggested a link between aromatase inhibitor therapy and breast density.

Jose Baselga, MD, PhD, and Michael Untch, MD, shared results from the NeoALLTO and GeparQuinto trials, respectively. NeoALLTO is a phase III, randomized, open-label, neoadjuvant study of lapatinib (Tykerb), trastuzumab (Herceptin), and their combination plus paclitaxel in women with HER2-positive primary breast cancer. GeparQuinto (GBG 44) is evaluating lapatinib vs trastuzumab in combination with neoadjuvant anthracycline- and taxane-based chemotherapy.

Results from an observational study strongly indicated that circulating tumor cells (CTCs) are an independent prognostic marker in metastatic breast cancer at first-line chemotherapy, and an early predictive marker of clinical benefit after one cycle of chemotherapy. But questions remain about the value of CTCs for guiding treatment decision-making.

The SUCCESS adjuvant therapy trial enrolled 2,026 women with primary breast cancer and no clinical evidence of metastatic disease. Disease-free survival at three years was 88.1% in women with one or more circulating tumor cells (CTCs) in their peripheral blood before undergoing chemotherapy compared with 93.7% in women with no CTCs.

Researchers from the ATAC and BIG 1-98 trials reported that CYP2D6 testing is not ready for prime time for gauging response to tamoxifen. While of the leading researchers in the field of CYP2D6 genotyping posed some key questions that need to be answered before CYP2D6 can be officially ruled out, or embraced, in clinical practice, these study results strongly suggest that CYPD2D6 testing should not be part of the standard of care, said Claudine Isaacs, MD.

As the FDA considers whether to rescind approval for bevacizumab (Avastin) in the adjuvant setting, “disappointing” results from the GeparQuinto study indicate the agent may be best reserved for patients with triple-negative disease.

Results from the GINECO group study demonstrate Afinitor’s ability to buy more time for patients while Xgeva makes everyday life less painful.

Exemestane provides a new option for upfront, five-year endocrine therapy in postmenopausal women, based on results of the first definitive early breast cancer trial to compare nonsteroidal and steroidal therapy.

Although there was no benefit for Zoledronic acid overall, the researchers reported significantly improved disease-free survival and overall survival in women who were more than five years postmenopause. Adjuvant bisphosphonate efficacy may be dependent on low estrogen concentration within the bone microenvironment, according to Robert Coleman, MD.

An analysis of multiple ECOG trials found that obese women with hormone receptor-positive breast cancer experience worse outcomes. But an exploratory analysis of the international TEAM trial indicated that obesity does not exert a negative influence on the efficacy of adjuvant endocrine therapy.

C. Kent Osborne, MD, codirector of SABCS 2010, spoke with Oncology NEWS International about what to watch for at this year’s meeting. Dr. Osborne highlights key studies in adjuvant therapy and aromatase inhibitor therapy and discusses some of the future challenges that the breast cancer community faces.

For women with triple-negative breast cancer, BRCA mutations can be a boon: These patients have a significantly lower risk of relapse than their counterparts who do not carry BRCA mutations, according to a study out of Houston’s M.D. Anderson Cancer Center. SABCS 2010 will feature an education session on the clinical utility of genetic testing for inherited predisposition to breast cancer.

For women with hereditary breast cancer, deciding on the best treatment option can be challenging. Three specialists, including medical oncologist Susan M. Domchek, MD, discuss the different approaches to managing breast cancer patients with a family history of BRCA mutations. Dr. Domchek will give a talk at SABCS 2010 on the management of women with a significant predisposition to breast cancer.

ASCO recently released updated guidelines on the use of adjuvant endocrine therapy in hormone-receptor-positive breast cancer. While the guidelines focus on all postmenopausal women, those who are age 75 and older require special consideration. Unfortunately, meaningful data to help healthcare providers make treatment decisions for these patients are scarce, according to Peter Ravdin, MD, PhD, an executive committee member and scientific program planning member of SABCS 2010.

The targeted combination of lapatinib (Tykerb) plus trastuzumab (Herceptin) led to a median overall survival of 14 months in women with refractory metastatic breast cancer, according to an updated analysis of the phase III EGF104900 trial. A bonus: The majority of toxicities were low-grade.

Despite a better dose loading schedule and compelling preclinical data, the combination of fulvestrant and anastrozole did not demonstrate any advantage in first relapse of hormone receptor-positive breast cancer, according to first results from the FACT trial.

Researchers in Taiwan and China found that alternating mammography and ultrasound led to a higher cancer detection rate in women aged 40-49. Meanwhile in the UK, a group from West Midlands Research Collaborative have made a case for starting screening at age 40 in certain ethnic groups. Finally, German investigators assessed the value of semi-annual ultrasound exams in high-risk women.

The RIBBON-2 trial met its primary endpoint to prolong progression-free survival, making the bevacizumab-chemotherapy combination a new treatment option, said principal investigator Adam Brufsky, MD. The trial continued the evaluation of bevacizumab plus chemotherapy to treat metastatic breast cancer after previous treatment failures.

Along with many other health issues, obese breast cancer patients face a particularly grim prognosis, with an amplified risk of recurrence and an increased risk of dying of the disease, according to results from a long-term, large-scale study in a Danish population. The researchers also noted that a larger body habitus negatively impacted treatment results.

Denosumab prevented more events, was better tolerated, and was more convenient for breast cancer patients with skeletal metastasis, according to results from a randomized double-blind trial that matched the RANK ligand inhibitor against zoledronic acid.

Exemestane alone and exemestane following tamoxifen, are equally appropriate treatment options, according to results from TEAM, the first trial prospectively powered to test the superiority of five years of aromatase inhibitors compared with a specific sequential strategy in postmenopausal women with endocrine-sensitive breast cancer.

Results from the CONFIRM trial found that a higher dose of fulvestrant was significantly more effective than a lower dose but did not lead to more toxicity, reported Angelo DiLeo, MD, who added “we anticipate that the 500-mg regimen will become the established dose for fulvestrant.”

SAN ANTONIO-Options for breast cancer prevention range from “noninvasive” lifestyle changes (diet, nutrition, exercise) to more radical surgical approaches. During an SABCS 2009 educational session, Judy Garber, MD, from Boston’s Dana-Farber Cancer Institute, outlined some of the advances in chemoprevention of ER-negative/HER2-positive breast cancers.

SAN ANTONIO-Investigators from Breast International Group 1-98 study and the Intergroup Exemestane Study updated their respective trial results at SABCS 2009. From the BIG 1-98 data, letrozole continued to show survival advantage, while exemestane offered protective benefits, based on IES study results.

Eidtmann H et al: The effect of zoledronic acid on aromatase inhibitor associated bone loss in postmenopausal women with early breast cancer receiving adjuvant letrozole: 36 months follow-up of ZO-FAST (abstract 44).

Patients with operable triple-negative breast cancer are at increased risk for recurrence if their tumor has higher levels of a protein-encoding gene implicated in migration, proliferation, and other cellular processes, reported Joseph A. Sparano, MD, from the Eastern Cooperative Oncology Group.

Lapatinib (Tykerb) plus letrozole (Femara) may delay disease progression in metastatic breast cancer patients, according to an international phase III trial. Patients who benefited from the protocol were those who overexpressed the HER2/neu protein and the epidermal growth factor receptor and were also hormone receptor-positive.