ABBA NETWORK

Little breast tumors that seemed cured after surgery are more likely to come back if they are the type known as HER2 positive, U.S. researchers reported on Friday.

They said women who have these types of tumors may need extra treatment with drugs such as Genentech Inc.’s Herceptin — which is not standard practice now.

“Most physicians do not treat these small tumors with Herceptin,” Dr. Ana M. Gonzalez-Angula of the M.D. Anderson Cancer Center in Houston, who led the study, told reporters in a telephone briefing.

After five years, 23 percent of patients with tiny tumors one cm (half an inch) or smaller whose cancer was HER2 positive had tumors come back after surgery, Gonzalez-Angula told the San Antonio Breast Cancer Conference.

Her team looked at more than 1,300 women between 1990 and 2003. Ten percent had HER2 tumors and they had a much higher likelihood the cancer would come back than those with the more common estrogen receptor positive tumors or those with so-called triple negative tumors.

These three types of tumor each have a different mutation that drives the cancer. Estrogen receptor positive breast tumors are the easiest to treat, with a range of drugs that affect the hormone.

The women, with an average age of 57, had 2.68 times the risk their cancer would come back after surgery if they had HER2-positive tumors than the other patients, Gonzalez-Angula told the meeting.

HER2-positive tumors had been more difficult to treat but Herceptin, known generically as trastuzumab, is a genetically engineered antibody — an immune system molecule — that homes in on that particular mutation.

Avastin, Genentech’s best-selling drug, increases the risk of people developing blood clots, according to a study published in the Journal of the American Medical Association.

For the study, researchers looked at data from roughly 8,000 cancer patients who participated in 15 clinical trials of the life-extending cancer medicine Avastin. The findings showed that high and low doses of the drug augmented risk of blood cloth equally.

An estimated 12 percent of patients taking Avastin developed blood clots in the veins. This figure is approximately 30 percent higher than in other cancer sufferers who are not taking the drug.

According to Kristina Becker, a spokeswoman for Genentech Inc., the label of Avastin already contains a warning about the risk of blood clots.

“I still think it’s a useful treatment,” lead researcher Shenhong Wu, a cancer specialist at Stony Brook University in Stony Brook, N.Y., said during a telephone interview. “But for some patients with a high risk of clotting, you may have to evaluate the risks against the potential benefits.”

Avastin received the U.S. Food and Drug Administration approval as a first-line treatment in combination with chemotherapy for patients without the squamous form of non-small cell lung cancer. The drug was also approved for use in breast and colon cancers.

Researchers who carried out the study said Avastin should get a “black box” warning from the Food and Drug Administration, since blood cloths put the lives of patients at risk.