As usual, news was plentiful at the San Antonio Breast Cancer
Symposium, which was held December 8-12, 2010. While The ASCO
Post will devote more space to key presentations in this and
future issues, many other studies are worth a mention:
1. The phase III international AZURE trial, conducted in 3,360
women, failed to show a benefit for zolendronate (zoledronic acid)
in improving disease-free survival when added to standard adjuvant
chemotherapy and/or hormonal therapy (abstract S4-5). The study contradicts
earlier findings from the ABCSG-12 study in premenopausal women,
where the addition of zolendronate improved disease-free survival
by 32% (P = .0009).
2. The addition of capecitabine (Xeloda) to standard adjuvant
chemotherapy did not significantly improve disease-free survival,
though there was a suggestion of benefit in patients with
triple-negative disease, according to the FinXX trial and US
Oncology 01-062 (abstracts S4-1 and S4-2).
3. Studies from the ATAC and BIG 1-98 trials of adjuvant
endocrine therapy showed that CYP2D6 phenotypes that are associated
with reduced enzyme activity in women receiving tamoxifen were not
associated with worse disease-free survival (abstracts S1-7 and S1-8).
4. The presence of circulating tumor cells in both metastatic
and early breast cancer patients was associated with worse breast
cancer outcomes (abstracts S6-5 and S6-6).
5. The notion that obese women have worse breast cancer outcomes
was modified somewhat by studies showing only some obese patients,
in particular those with hormone receptor-positive, HER2-negative
disease, had an increased risk for recurrence and death. In short,
breast cancer subtype may matter, according to a multivariate
analysis of several ECOG studies (abstract S2-1).
6. Aromatase inhibitors appear to increase the risk of cardiac
events, according to a Canadian study that found a 26% increased
risk except among women treated with tamoxifen first, then switched
to an aromatase inhibitor (abstract S2-7).
7. Despite the uproar over the U.S. Preventive Services Task
Force recommendations in 2009, many women still do not get screened
by mammography. In a study of more than 1.5 million women,
annual mammography rates averaged only 50% in women aged 40 and
older, despite the fact that most patients had continuous insurance
coverage, a study from Medco Health Solutions showed (abstract S4-7).
8. Radiation therapy can be sandwiched between chemotherapy
cycles without a loss of disease control. In fact, a 2% benefit in
locoregional control was shown by a study from the United Kingdom
in which radiotherapy was delivered between cycles 2 and 3 of CMF
(cyclophosphamide, methotrexate, fluorouracil) or between cycles 5
and 6 of anthracycline/CMF chemotherapy. This approach shortens
treatment time while maintaining the intensity of chemotherapy and
only modestly increasing the risk of skin toxicity (abstract S4-4).
9. In two studies that examined data from the Women's Health
Initiative, hormone replacement therapy with estrogen alone (in
women without a uterus) was shown to be protective against breast
cancer, whereas combined estrogen/progestin therapy increased risk
(abstracts P6-09-09 and S6-1).
10. In the first results of CALGB 40101, which is comparing
chemotherapy with AC (doxorubicin, cyclophosphamide) to paclitaxel
alone, a regimen of four cycles of chemotherapy (AC or paclitaxel)
was not inferior to six cycles and was better tolerated (abstract S6-3). The comparison between the
types of chemotherapy is not mature. ■
