Personalized Cancer Care Off to Slow Start (Questions Tamoxifen CYP2D6 testing)

[Rich66]

http://www.gooznews.com/node/3250

With the cost of new cancer drugs soaring to $10,000 a month or more, genomic analyses of cancer tumors hold out the hope that oncologists will be able to identify in advance which patients will benefit from use of pricey new drugs. A new draft report from the Agency for Healthcare Research and Quality suggests that day is still a ways off.
In the finding most likely to cause controversy, the AHRQ report found there was "no consistent associations" between breast cancer patients with the relevant CYP2D6 polymorphism and the outcome of tamoxifen therapy, whether as primary treatment or in as post-operative adjuvant therapy. Estimates vary, but anywhere from 10 to 40 percent of women have the gene variant of CYP2D6 that is believed to slow the metabolism of tamoxifen and make it less effective. A number of companies sell a $300 test that can show if women have the allegedly telltale CYP2D6 polymorphism.
As is often the case, the 13 studies identified by the systematic review didn't contain enough data to draw definitive conclusions. "Most studies were relatively small and thus underpowered to detect what would be a plausible effect size for the modification of response to tamoxifen by a single polymorphism," the report noted.