Published on September 26, 2011 at 4:31 AM
The results provide no evidence that the duration or depth of sevoflurane anesthesia affects the risk of new-onset cancer. Dr. Lindholm and coauthors emphasize that their findings do not apply to patients undergoing cancer surgery, or those with previous cancer. They also note that their study cannot explain the possible increase in cancer risk among patients undergoing surgery, compared to the general population.
In an editorial, Dr. Kate Leslie of University of Melbourne, Australia, and Dr. Timothy G. Short of Auckland City Hospital, discuss the importance of "negative" studies refuting previous results. There's a recognized phenomenon of "publication bias" and other forms of "dissemination bias," in which follow-up studies don't get the same attention as initial, high-profile findings—and sometimes aren't published at all.
Drs. Leslie and Short hope the new report will influence further research to build on the results. They suggest that it might be better to perform further observational studies before any large randomized trial on the effects of general anesthesia on cancer risk. They conclude, "[I]f there is a small effect that has been missed by this study, a very large and expensive trial would be required to detect it."
Like other major medical journals, Anesthesia & Analgesia has made a concerted effort to reduce discrimination against negative studies. "The new results are good news—there was no increase in the rate of new cancer in previously cancer-free patients undergoing general anesthesia," comments Dr. Steven L. Shafer of Columbia University, Editor-in-Chief of Anesthesia & Analgesia. "Although this was a 'negative' study, it had adequate statistical power to identify small changes in cancer risk associated with anesthesia."
Source: Anesthesia & Analgesia