A University study published last week found that a common treatment for cancer pain actually promotes tumor growth in laboratory mice.

Researchers, led by Dr. Kalpna Gupta, implanted human breast cancer tumor tissue into the mice. They then injected the animals with morphine dosages proportionate to those human cancer patients regularly receive. The drug stimulated blood vessel growth, or angiogenesis, which provides nutrients to existing tumors.

The findings could change the way doctors treat pain in cancer patients, but Gupta, a University professor, said there’s not enough evidence yet to suggest doctors should stop prescribing the drug.

“This research was only in animals,” Gupta said. “There is no data for humans.”

It could still be several years before human testing is completed, Gupta said. If researchers produce similar findings in human patients, it would not only have implications for cancer pain relief. Gupta said blood vessel growth is also important to wound healing and some cardiovascular diseases, for example. Morphine or a similar opiate could be made to help spur vessel growth in these instances.

The study was published in last Thursday’s issue of Cancer Research.

Dan Haugen welcomes comments at [email protected]