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Lani
11-17-2006, 11:05 AM
November 17, 2006 — For postmenopausal women with hormone-sensitive early-stage breast cancer, there is a survival benefit in switching to the aromatase inhibitor anastrozole (Arimidex, AstraZeneca) after an initial period on tamoxifen (Novaldex, AstraZeneca), a new meta-analysis shows.

Combining data from 3 studies revealed a significant improvement in survival with anastrozole, even though none of the studies individually showed this effect, researchers report in a paper published November 17 in Lancet Oncology.

“A lot of people have been waiting to see whether aromatase inhibitors will show a survival advantage, and I think this data will reassure them that 5 years of tamoxifen is no longer the standard of care,” lead author Walter Jonat, MD, from the University of Kiel, in Germany, comments in a statement.

“The best treatment for women with hormone-sensitive early-stage breast cancer should include an aromatase inhibitor,” he says.

Findings Challenge Existing Gold Standard

For the past few decades, the existing gold standard has been 5 years of adjuvant tamoxifen therapy after primary treatment for postmenopausal women with hormone-sensitive early-stage breast cancer. In recent years, however, aromatase inhibitors have been added on or used instead, and such use has been included in guidelines issued by expert bodies such as the American Society for Clinical Oncology (ASCO) and the National Comprehensive Cancer Network (NCCN), the authors note.

“Our findings further challenge the existing standard clinical approach of 5 years’ adjuvant tamoxifen therapy,” they add.

Using Individual Patient Data From 3 Trials

Dr. Jonat and colleagues combined results from 3 trials: the Austrian Breast and Colorectal Cancer Study Group (ABCSG 8), Arimidex-Novaldex (ARNO 95), and the Italian Tamoxifen Anastrozole (ITA) studies. The meta-analysis was sponsored by AstraZeneca.

A total of 4006 women were involved. All the participants had been taking tamoxifen (20 to 30 mg/day) for 2 to 3 years and were then randomized to continuing to take it or to switching to anastrozole (1 mg/day).

Lani
11-17-2006, 11:18 AM
The meta-analysis revealed that patients who switched to anastrozole had fewer disease recurrences (92, vs 159 on tamoxifen) and deaths (66, vs 90 on tamoxifen). This resulted in significant improvements in:
Disease-free survival (hazard ratio [HR], 0.59; P < .0001).
Event-free survival (HR, 0.55; P < .0001).
Distant recurrence-free survival (HR, 0.61; P = .002).
Overall survival (HR 0.71, P = .04).

The researchers note that the patient population of the ITA study (n=448) differed from those in the other 2 studies: the majority were node-positive, and more patients had undergone a mastectomy and received chemotherapy than in the other trials. However, these differences should not affect outcome, as the meta-analysis used individual patient data, they comment. “Indeed, the benefit of anastrozole over tamoxifen was evident irrespective of nodal status [or] tumor size or whether the patient had received chemotherapy.”

“We showed that the benefits of switching to anastrozole in terms of disease- and recurrence-free survival that have been seen in the individual trials translate into a significant benefit in overall survival,” Dr. Jonat commented. The technique of meta-analysis “increases the power and precision of the analysis, helps to avoid bias or random error, and can therefore address questions that cannot be answered from the individual trials.” Despite this powerful technique, however, there are many questions that remain, he added. Future research will need to address the optimum duration of treatment, whether tamoxifen or aromatase inhibitors should be given first, and whether any combinations of other drugs may improve further on these results.

“Clearly, real data from well-designed clinical trials are needed to inform treatment strategies,” the authors note. “However, the survival benefit that emerged from our analysis — and not present in any trial that assessed aromatase inhibitors as initial adjuvant treatment — suggests that a tamoxifen induction period could be beneficial, despite the fact that relapse rates might be highest in the first 2 years.”

Lancet Oncol.

The drug co. sponsored , European studies, mostly didn't test her2 status and many patients with ER+ tumors were treated with hormonal therapy wout chemo (often CMF instead of AC +/-T)

they think there still could be a
beneficial effect of starting with tamoxifen


her2+ patients -? easier time getting AIs despite price diff. (govt decisions)