(AP) — New research raises fresh questions about which cancer patients benefit from Avastin (uh-VAS’-tihn), a drug that lost its approval for treating breast cancer nearly two years ago.

Two studies found that Avastin did not prolong life when used as a first treatment for people with brain tumors like the one U.S. Sen. Edward Kennedy died of several years ago. Side effects also were more common with Avastin.

The drug is approved for treating brain tumors that have recurred and doctors say it should still be used in those patients.

Other research shows it extends survival for women with advanced cervical cancer. Avastin also is used to treat certain colon, lung and kidney tumors.

The studies were discussed Sunday at a cancer conference in Chicago.