New research, new perspective on effectiveness

Endometrial cancer is the most common malignancy of gynecological cancers among women in the United States. That’s a fact that physicians may know, but many women do not. The mass media is fast to cover ovarian and cervical cancer, but somehow endometrial cancer remains a mystery to many women across the country.

There is always good reason to talk to your patients about endometrial cancer, but now there is one more. Recent research via a multicenter Dutch study shows that vaginal brachytherapy is as effective as external-beam radiation at preventing the recurrence of higher-risk endometrial cancer. What’s more, the treatment is faster for women and known for less toxicity. The latest findings—know as the PORTEC II trial—were presented in June at the Annual Meeting of the American Society of Clinical Oncology in Chicago.

The study involved 427 women with high-intermediate risk endometrial cancer. These women were randomly assigned to receive either external beam pelvic radiotherapy or vaginal brachytherapy. The findings: After 3 years, the vaginal relapse rate was 1.9% with external radiotherapy versus 0.9% with brachytherapy.

Crux of the Matter

“I think that for most of us radiation oncologists, this is not really big news; we already suspected this was the case,” said Beth Erickson, MD, professor of radiation oncology at the Medical College of Wisconsin. “However, it is really important because this latest research offers proof that in many cases you can basically omit external beam radiation to the whole pelvis.” The news is vital for OB/GYNs, gynecological oncologists, and surgeons—as any and all of these specialists may be involved in a patient’s postsurgical follow-up treatment.

A vaginal HDR brachytherapy applicator set, including CT cylinders, from Varian Medical Systems.

Vaginal brachytherapy is a localized type of radiation treatment. Known as high dose rate (HDR) therapy, it relies on iridium 192. After the patient recovers from surgery, a radioactive applicator or cylinder is inserted into the vagina. The goal, says Erickson, is to avoid “vaginal recurrences,” especially near the vaginal cuff. “If some malignant cells are embedded in the surgical scar, for example, vaginal brachytherapy can eradicate those cells and prevent a recurrence of endometrial cancer in the vagina,” Erickson said.

While recurrence rates of endometrial cancer are relatively low (0 to 20% risk), it is critical to take preventive measures in high-risk women, Erickson said. Why? If found too late, “only 60% to 70% of patients with recurring endometrial cancer can be cured,” according to Erickson, who treats patients at Froedtert Hospital, Milwaukee.

Experts say vaginal brachytherapy is designed for select candidates. “I believe most US institutions would agree that women with stage 1B, grades 2 and 3, and those with stage 1C, grades 1 through 3, may be good candidates for the treatment,” Erickson said.

Quality of Life Issues

“With vaginal brachytherapy, we can treat the highest area at risk,” Erickson said. Moreover, Erickson said that while external beam radiation is well tolerated by most patients, vaginal brachytherapy is much shorter and easier.

External beam radiation typically requires daily treatments over the course of 51/2 weeks. Vaginal brachytherapy is often done on an outpatient basis and typically calls for “three to six treatments of 3 to 5 minutes in length over 3 to 5 weeks,” Erickson said.

“It also offers a good risk to benefit ratio,” Erickson said. “There is modest radiation dosage, and quality of life for patients going through this therapy is excellent.” Erickson notes that vaginal brachytherapy is associated with few side effects. “Later effects—years later—may include narrowing of the vagina. And rarely, mild irritation of the bladder or rectum,” Erickson said.

Vaginal brachytherapy has been available in the United States for several decades. It was introduced previously in Japan and England. Not surprisingly, Memorial Sloan Kettering was among the early adopters of the technology in the United States.

According to Erickson, Nucletron and Varian are the leaders in the field. Both companies make the vaginal applicators as well as software for planning treatments. “They both do a great job,” said Erickson, whose institution uses Nucletron’s technology. “These manufacturers have been doing it a long time and really understand the technology.” Erickson noted that there are new emerging companies working on vaginal brachytherapy technology as well. “Innovation is ongoing and that’s good,” Erickson said.

Is PET Next?

So what is next in the way of imaging solutions for endometrial cancer? Erickson is a big proponent of PET scanning—sometimes before, and sometimes after, surgery, depending on the case. “We’ve been using PET for a while now in very high-risk women, for several reasons,” Erickson said.

Lymph nodes, even after many are removed surgically, can make for cancerous culprits. As Erickson explained, PET scans can prove to be lifesavers. “The sugar compound used in PET is taken up by metabolic cells,” Erickson said. “Tissue with cancer will take up the compound, and we can see the metabolically active areas highlighted in a different color.”

But like all good things, there are downsides to PET. For starters, Erickson said it can lead to false positives. Moreover, while PET is reimbursable for cancer of the cervix, it is not yet Medicare approved for endometrial cancer.

But back to the subject at hand. The new Dutch research indicates that vaginal brachytherapy is a smart, preventive measure for women with higher-risk endometrial cancer. That’s an ounce of prevention we cannot afford to ignore.

Marianne Matthews is editor of Axis Imaging News. For more information, contact .