THURSDAY, June 9 (HealthDay News) -- Some patients with advanced cancer receive drugs that won't help them but could cause them harm, a U.S. study suggests.

University of Chicago researchers analyzed medical and pharmaceutical claims from 1,041 patients with metastatic colon cancer who were treated between January 2007 and June 2010. Of those patients, about one in eight received chemotherapy treatments that weren't supported by evidence from clinical trials or by clinical practice guidelines.

The researchers focused on three specific treatments. One had insufficient data to support its use, one had been shown to be ineffective, and one was not supported by data or a compelling rationale, according to the study.

The treatment with insufficient data involved the use of Avastin (bevacizumab) after a patient's cancer had progressed despite treatment with a combination of the drug and chemotherapy. The treatment shown to be ineffective was Xeloda (capecitabine) after cancer progression while being treated with the same class of drug. The treatment with no compelling rationale was Erbitux (panitumumab/cetuximab) after cancer progression while being treated with similar drugs.

The researchers said the patients who received these treatments were exposed to significant risk without proven benefits at an estimated cost of more than $2 million just for the drugs.

"Patients with advanced cancers that do no respond to standard therapies should either be looking for clinical trials, where there is a chance for benefit, or should have been thinking about shifting toward palliative care," study author Dr. Jonas De Souza, a hematology/oncology fellow, said in a university news release.

"Patients should not face the risks, discomforts and costs of aggressive and often quite toxic chemotherapy with treatment regimens that did not provide a benefit in previous studies," he added.

The study was presented this week at the American Society for Clinical Oncology's annual meeting in Chicago. Experts note that research presented at meetings should be considered preliminary because it has not been subjected to the rigorous scrutiny given to research published in medical journals.

More information

The U.S. National Cancer Institute has more about metastatic cancer.