Ultrasound’s New Focus

Can it Eradicate Tumors?

Science News, April 29, 2006 by Ben Harder

Sounding Out Malignancies

Continued from Wednesday’s article.

Unlike fibroids, malignant tumors need to be rooted out entirely if they’re to be beaten. In surgery, doctors remove a specific amount of surrounding healthy tissue to avoid leaving behind any cancer cells. Similarly, in HIFU, doctors may need to kill a veneer of healthy tissue around each tumor, concluded Moshe Papa and Douglas Zippel of Sheba Medical Center in Tel Hashomer, Israel, in the January 2005 Breast Cancer.

Aim and Fire — Inserted into the rectum, an ultrasound device images the prostate (top) and then focuses tumor-killing waves at points inside the gland (bottom).

Those researchers used HIFU to treat 10 women who had breast cancer and were planning to have partial mastectomies. After the procedure, the investigators removed a portion of each treated breast to see whether HIFU had eliminated the tumors. Two volunteers showed no sign of remaining cancer, but eight patients retained at least some cancerous cells at the tumor site. Feng Wu and his colleagues in Chongqing, China, have taken a more aggressive approach. Between 1998 and 2001, they administered HIFU–in combination with either surgery or chemotherapy–to 45 women with breast cancer. They intentionally destroyed a 1.5-to-2-centimeter-thick layer of normal tissue around each tumor.

Five years later, 89 percent of the women had had no recurrence of disease, Wu reported last December at the Radiological Society of North America meeting in Chicago. Wu holds stock in the company that makes the device that his team tested. The study didn’t include a comparison group of similar patients receiving a conventional treatment.

In other studies, it’s not uncommon to find that after surgery and radiation therapy, more than 90 percent of volunteers who have breast cancer go at least 5 years without recurrence.

InSightec-sponsored researchers have begun a trial of HIFU in treating breast tumors and surrounding breast tissue in 200 women in Germany and Japan.

The cosmetic side effects of HIFU are minimal. Since HIFU doesn’t break the skin, it rarely disfigures the breast, Wu says. David Gianfelice of Toronto General Hospital, one of the first North American researchers to use HIFU in breast cancer treatment, notes that third-degree skin burns have resulted in some cases. But recent refinements to the InSightec hardware have minimized that problem, he says.

By delivering “a nice, tight package of heat” to the tumor, MR-guided HIFU might eventually supplant surgery as the treatment in some cases of breast cancer, Gianfeliee says. That same goal applies in prostate cancer, which researchers abroad have been treating with HIFU since the mid-1990s. For example, more than 400 men with early-to-mid-stage prostate cancer have received HIFU as an initial therapy using the device manufactured by EDAP of Vaulx-en-Velin, France.

Andreas Blana and his colleagues at the University of Regensburg in Germany reported results from 146 of these patients, who were tracked for an average of nearly 2 years. Blana’s team reported in the Febmary 2004 Urology that 87 percent of the patients remained free of their cancer. In studies of traditional prostate cancer therapies, up to 95 percent of men with earlystage cancer remain caneerfree at least 5 years after treatment.

At Hachioji Hospital in Tokyo, Toyoaki Uchida and his colleagues have treated more than 200 men since 1999. Overall, 81 percent of the men remained free of disease 1 year after the procedure, and 77 percent had no disease after 5 years, Uchida reported at a meeting of the International Society for Therapeutic Ultrasound in Boston last October.

But more evidence is needed to prove that HIFU rids men of cancer as effectively as established therapies do, says urologist Peter Scardino of Memorial Sloan-Kettering Cancer Center in New York City. Other researchers are now testing HIFU in patients with terminal liver or brain cancer or patients in whom tumors from other organs have spread to bone. These trials are intended to relieve pain.

Please come back on Sunday for the conclusion of the article.