New Canadian study demonstrates clear survival benefit of treatment in trials and at large centres


Hamburg, Germany: A new Canadian study has found that breast cancer patients who were treated according to accepted standards of care or who took part in clinical trials were from 30% to 60% less likely to die from any cause during a seven-year follow up period.

Lead researcher Dr Nicole Hébert-Croteau told the 4th European Breast Cancer Conference today (Friday 19 March) that the findings confirmed the assumption that breast cancer patients benefited from taking part in clinical trials. Treatment in centres that dealt with large numbers of cases was also associated with better survival.

Dr Hébert-Croteau and her team studied 1,727 women with early node-negative breast cancer in five regions of Quebec over a median follow up period of nearly seven years. The regions covered over 60% of the population of the province. Of the 57 hospitals taking part, 16 were involved in collaborative clinical trials during part or whole of the 1988-1994 study period. Larger centres treated more than 100 women a year with breast cancer, the medium sized centres treated between 50 and 100 and small centres treated fewer than 50.

The overall survival among all the women in the study at seven years was 82%. But, when measured against women in the study who had not been treated according to accepted guidelines and who had not taken part in research, patients whose treatment followed the guidelines had 0.7 times the risk (or 30% less likelihood) of dying from any cause during the follow up period while women who had taken part in research had 0.4 times the risk (or 60% less likelihood) of dying in the follow up period.

Dr Hébert-Croteau, a consultant physician and epidemiologist at the Quebec National Institute of Public Health, said: "There is some overlap in the confidence intervals of these figures so, from a statistical point of view, the 60% could not be interpreted as being different from the 30%. And of course, the better outcome for women treated in centres with larger caseloads is partly explained by the fact that these centres usually also participate in research and vice versa.

"But what is clear is that, since we adjusted for key prognostic factors among the women, the explanation for the better survival was not due to any baseline characteristics of the patients or to them being selectively chosen to participate in clinical trials."

She said that the specific strength of the analysis examining participation in clinical trials was that it was population-based and assessed all the breast cancer trials available to women with node-negative breast cancer in Quebec during the study period and had not confined itself to one specific trial protocol or a few.

"The lessons from our findings are that women derive substantial benefit from participating in clinical trials and that their gain in survival is at least as great as compliance with current standards of care. It is also clear that the better outcome for patients treated in larger centres is partly explained by these centres' participation in research. Treatment centres should be encouraged to become affiliated to the networks of collaborating institutions so that more patients can share in these benefits."

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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