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Impact of a scientific presentation on community treatment patterns for primary breast cancer.
by Giordano SH, Duan Z, Kuo YF, Hortobagyi GN, Freeman J, Goodwin JSJournal of the National Cancer Institute.
Article Abstract:
BACKGROUND: The publication of results from randomized clinical trials can have a dramatic effect on treatment patterns, but the impact of oral presentations at national scientific meetings is unknown. We investigated the temporal association between the oral presentation of the results from the Cancer and Leukemia Group B (CALGB) Study 9344 at the May 1998 meeting of the American Society of Clinical Oncology, which showed that paclitaxel improves survival of women with lymph node-positive breast cancer, and use of taxane chemotherapy for breast cancer. METHODS: We studied chemotherapy use in 3341 women identified through the Surveillance, Epidemiology, and End Results-Medicare database who were diagnosed with stage I-III breast cancer in 1994-1999 at age 65 years or older and received adjuvant chemotherapy, as identified through claims data, within 1 year of diagnosis. We assessed the temporal association between the CALBG presentation and taxane use with piecewise regression analysis. Multivariable logistic regression analysis was used to determine which patient characteristics were associated with taxane use. RESULTS: The use of taxanes increased substantially after the CALGB presentation, with absolute rates of taxane use of 5.2% before May 1998 and 23.6% in May 1998 and later. Initially, this increase was confined to patients with lymph node-positive disease (40% of whom were receiving taxanes by the end of 1999), but over time it extended to patients with lymph node-negative disease (15% of whom were receiving taxanes by the end of 1999). In multivariable analysis, patients who were treated in May 1998 or later were statistically significantly more likely to have received a taxane than patients treated before this date (estimated relative risk = 6.84, 95% confidence interval = 5.71 to 8.07). Younger patient age, larger number of lymph nodes involved, higher tumor grade, and larger tumor size were also independently associated with adjuvant taxane use. CONCLUSIONS: The oral presentation of a single study at a national conference was temporally associated with an increase in the use of taxanes for primary breast cancer, even before study publication or Food and Drug Administration approval.
The Impact of Pre-Publication Presentation of Results
By: Epidemiologic Inquiry - Sat 10/07/2006 AMWhen is it a good idea, and when is it a bad idea to announce scientific results before formal publication? Does the medical community and the public quickly adopt pre-publication findings even though the results are not yet peer-reviewed? Such were the questions address by the recent article in JNCI by Giordano et al. and its accompanying editorial by Woloshin and Schwartz.
Giordano et al. investigated whether a new taxane treatment for lymph-node positive breast cancer significantly increased after its efficacy results were reported at the May 1998 meeting of the American Society of Clinical Oncology. Even though the taxane was not yet FDA approved and the formal publication was not to appear until 5 years later, the authors found that use of the newly reported treatment significantly increased >400% overall after the conference report. Furthermore, even though the treatment was shown only efficacious in lymph-node positive breast cancers (use increased 800%), results also showed that its use in patients with lymph-node negative breast cancers also increased 300%, which is in fact quite clinically disturbing as the drug was not even shown efficacious for such a disease.
The accompanying editorial by Woloshin and Schwartz summarized the risk and benefits of early adoption of pre-publication results, as well as noted examples in which early adoption has been clinically detrimental. Notably, the drug gefitinib (Iressa) had once been granted early FDA approval for increasing survival of patients with non-small-cell lung cancer who failed chemotherapy, even though the trial was unpublished, was a single uncontrolled trial, and subsequent issues were raised regarding adverse pneumonia deaths. Though over 200,000 people used the drug by 2004, a subsequent placebo-controlled trial shows no increased survival benefit. Such is an example in which adoption of pre-publication results did not benefit the public, and may have in fact caused more harm.
Woloshin and Schwartz summarize the following set of guideline regarding when to potentially adopt any pre-publication results: 1) large difference in all-cause mortality 2) no adverse effects 3) results are from a large randomized trial with long duration 4) confirms prior trial results, or presents first randomized trial evidence 5) no alternative treatments exist
[The original version of this review premiered in Epidemiologic Inquiry: http://www.epidemiologic.org/2006/10/impact-o...