More women are surviving advanced breast cancer, French researchers say, and better treatments are probably the reason.

Writing in the Journal of Clinical Oncology, (Vol. 22, No. 16: 3302-3308), doctors from 3 French hospitals reported on 724 women whose first diagnosis was breast cancer that had spread to other parts of the body (stage 4). It is rare for women to be diagnosed with such late stage disease. The women in the study accounted for less than 5% of the breast cancer patients treated at those centers.

The researchers divided the women into 2 groups, those diagnosed between 1987 and 1993 (343 women) and those diagnosed between 1994 and 2000 (381 women).

Women in the later group fared much better: 44% of them survived 3 years after diagnosis, and 28% survived 5 years. Among women in the earlier group, just 27% survived 3 years and 11% survived 5 years.

The researchers think better drugs made the difference. The 1990s saw an explosion in new treatments for breast cancer, including the chemotherapy drugs paclitaxel, docetaxel, and others, the monoclonal antibody trastuzumab, and aromatase inhibitors like anastrozole, letrozole, and exemestane. Paclitaxel was approved for metastatic breast cancer in France in 1993, which is why the researchers used that date as the dividing line for their study groups.

Not surprisingly, more women in the later group were given these new medications. Just 10% of the women treated between 1987 and 1993 received one of these drugs, compared to 58% of the patients diagnosed later. Among the women in the later group who survived at least 3 years, 76% were treated with one of the new drugs.

The researchers did not try to determine which treatments were responsible for the improved survival in the later group of women. However, the improvements were seen only among women who had hormonally sensitive cancers, suggesting that hormonal therapies -- like the aromatase inhibitors -- may have played a role.

Of course, better diagnosis may also have had an impact. Although the technologies used to diagnose breast cancer were the same through both study periods, the researchers say it is possible that women in the later group were diagnosed when their cancer was slightly less widespread. Overall, though, the two groups of women were very similar in terms of age, where their cancer had spread, and the percentage with hormonally sensitive cancers.

The researchers say their findings aren't necessarily applicable to women who start out with an earlier stage cancer that then goes on to spread to other parts of the body, because women in this situation weren't studied. Nevertheless, their findings are good news for women facing a devastating diagnosis of advanced cancer.