Thursday, September 11, 2008

In the Dark?

Most cancer patients who enter phase 1 clinical trials are motivated by the prospect of controlling their cancer. Increasingly, however, such studies, in the words of one ethicist, "take without giving in return" by involving biopsy procedures in which tissue is collected before and during the study in order to gauge whether a new drug is having intended biological effects. Such procedures are potentially burdensome, and offer no direct benefits for patients.

So is it ethical for clinical investigators to "stick it to" their research subjects? Depends in part on the level of risk. In the August 20, 2008 issue of Journal of Clinical Oncology, Aaron P. Brown and coworkers at NIH performed a literature review examining the complication rate for research biopsies in the context of studies involving radiotherapy ("Performing Nondiagnostic Research Biopsies in Irradiated Tissue: A Review of Scientific, Clinical, and Ethical Considerations"). One might expect to find higher than usual complication rates in this context, because irradiation can interfere with wound healing.

Here is what they found. Of 29 eligible studies, only 3 (!!) actively evaluated adverse events related to biopsy (another 16 reported adverse events– but not specifically related to biopsy) These 3 studies reported a total of 17 adverse events.

Here is what the authors concluded: "Limited data suggest that biopsies can be performed in irradiated tissues without clinically significant excess risk."

The authors sagely argue that "all clinical trials that perform biopsies in combination with other therapies should actively study and report complications." But with their specific study question- the complication rate of tissue biopsies- so underexposed, the their conclusions are dodgy. (photo credit: Moominsean 2006)

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