cancer radiation therapy reduced to five days

Sitting in an exam room after her mammogram, Virginia Purdy was unable to hear or speak. She could only recall the words: “You have a suspicious mass that we need to biopsy right away.”

The resulting biopsy revealed that Purdy, 59, had a malignant tumor in her left breast. Seeking out the best possible treatments, she discovered a minimally invasive method of delivering radiation therapy called MammoSite® offered at The Methodist Hospital.

Developed for patients with earlystage breast cancer who have had lumpectomies (the removal of a cancerous lump and a portion of the

BY MELANIE M C FARLANE surrounding tissue), MammoSite delivers high-dose radiation directly to the site where the tumor was removed. It targets the spot where cancer would most likely recur and spares surrounding healthy tissue. Purdy was referred to Methodist radiation oncologist Dr. Hsin Lu after her lumpectomy. Lu, whose practice is comprised almost entirely of breast cancer patients, said traditional whole breast radiation is considered the current standard of care, with high energy X-rays delivered to the skin, breast and other tissue.

Breast cancer radiation therapy reduced to five days

Dr. Michael Coselli

“It was previously believed that irradiating the whole breast would decrease the chances of the cancer recurring. In fact, research shows that MammoSite, which minimizes exposure to the rest of the breast and surrounding organs by targeting radiation only to the area where tumors are most likely to recur, has a low risk of recurrence. More importantly, it has fewer side effects for patients,” she said.

MammoSite uses a balloon catheter to deliver the radiation source or “seed.” The catheter is placed inside the cavity created after the tumor is removed. Next, the seed is inserted into the balloon and left there for five to 10 minutes twice daily, with six hours between doses. After five days the balloon is deflated, the catheter is removed and a small amount of antibiotic and gauze are placed over the site.

Lu said the benefits of MammoSite are numerous. The radiation source is placed inside the lumpectomy cavity, delivering radiation to only the area where cancer is most likely to recur. Therefore, the amount of radiation to healthy tissue is limited, reducing the potential for side effects and overwhelmingly increasing patient satisfaction.

“With only two treatments per day for five days, MammoSite radiation therapy is a convenient option for patients who work. It’s also suitable for those traveling from another city to receive treatment,” she said.

When Purdy finished the MammoSite treatment early this year, she marveled at how easy it was. “I work downtown, and every morning and every afternoon, I simply rode the light rail into the Medical Center, received my treatment and went back to work.”

She learned about MammoSite at Fayez Sarofim & Co. where she works. The company’s owner, Fayez Sarofim, is a strong philanthropic supporter of the medical community and makes health information available to his employees. “I’m fortunate my employer was so supportive of my need for treatment. Many women do not have careers that can accommodate six weeks of therapy,” Purdy said.

Lu says that in spite of this less invasive and decreased treatment time, 40 percent of women still opt for a mastectomy. “The combination of lumpectomy and MammoSite appears to be an effective and more

convenient option, but this treatment has only seven or eight years of followup results, whereas a mastectomy has 20 to 30 years of results.”

The recurrence rates paint a more detailed picture for patients considering both treatments: lumpectomy alone results in a 20 to 30 percent recurrence of breast cancer. Lumpectomy combined with whole breast radiation has a five to 10 percent recurrence. When lumpectomy is combined with partial breast radiation, there is only a zero to five percent chance of recurrence.

Early detection is key

Breast cancer is the leading cancer in women, and it is estimated that one in eight women in the United States will develop breast cancer in her lifetime. With these statistics, early detection is critical for women wishing to undergo breast conservation therapy.

Dr. Michael Coselli, a surgeon at The Methodist Hospital, performed Purdy’s lumpectomy to effectively treat the cancer while avoiding complete removal of the breast (mastectomy).

“Lumpectomies are the standard treatment for early detected localized cancer with survival rates equal to mastectomies,” Coselli said. “This surgical approach is optimal for patients with malignant tumors — usually less than four centimeters that can be removed with clear margins (no cancer cells in the tissue surrounding the tumor).”

The earlier a tumor is detected, the smaller the lumpectomy and chances are better for a successful treatment if the tumor is malignant. “The key message here is that early detection saves lives and also provides more options for less invasive therapies like MammoSite,” said Dr. Luz Venta, director of imaging at the Methodist Breast Care Center.

Venta performs diagnostic imaging, primarily mammograms and ultrasounds. “Annual mammograms for women 40 and older are essential for improving the rate of early detection,” she said. “Yes, there are risk factors that make some women more susceptible to breast cancer, but more than 90 percent of women diagnosed never have one of those risk factors.”

It is expected that in five to 10 years MammoSite will replace traditional whole breast radiation as the standard of care for early detected breast cancer. “With patient word of mouth, more and more patients are discovering the benefits of MammoSite,” Venta said.

Purdy is a strong advocate for MammoSite. “I have recommended it to many others. The time between my diagnosis and completed treatment was less than two months. Not only am I now a cancer survivor, but I survived with hardly any interruption in my life.”

How MammoSite Radiation Therapy System works

Images courtesy of Cytyc Corporation and its affiliates The MammoSite balloon is placed into the center of the surgical cavity. The balloon is then inflated to optimally position the breast tissue to receive the radiation dose.

During the radiation treatment, the catheter is attached to a machine that houses the radiation source. A thin wire with a tiny radioactive seed on the end moves up the catheter under precise computer control into the center of the balloon. The seed irradiates the tumor site and the area immediately surrounding the cavity where tumors are most likely to recur. After the patient receives the prescribed dose of radiation over a five-to-10-minute period, the seed is removed from the balloon. After five days of treatment, the balloon is deflated and easily removed from the breast.