Large trial Down Under proves PET/CT in ovaries

October 1, 2007

The largest multicenter prospective trial of PET/CT ever conducted in Australia has found that the combined imaging modalities can identify women with a history of ovarian cancer who are susceptible to recurrence of the disease. The hybrid imaging modality can detect more sites of disease than CT or ultrasound and changes patient management in many cases.

The largest multicenter prospective trial of PET/CT ever conducted in Australia has found that the combined imaging modalities can identify women with a history of ovarian cancer who are susceptible to recurrence of the disease. The hybrid imaging modality can detect more sites of disease than CT or ultrasound and changes patient management in many cases.

PET was introduced in Australia in the early 1990s, with limited financial support from the Commonwealth government. When government officials reviewed results from the first PET/CT trial for suspected recurring ovarian cancer in 2000, they concluded that there were not enough patients to prove the efficacy of hybrid imaging but agreed to support further data collection.

The additional data, from patients recruited between December 2003 and February 2006, helped researchers to arrive at the conclusion that PET/CT should be the imaging technique of choice for suspected recurrence, said Dr. Michael J. Fulham, chief of PET and nuclear medicine at the Royal Prince Alfred Hospital in Sydney.

Using PET/CT, Fulham and colleagues found at least 168 additional sites of mostly nodal or peritoneal lesions not identified by either CT or ultrasound in almost two-thirds of 90 patients with suspected recurrence. The patients with additional disease sites were more likely to have a recurrence of their ovarian cancer within a year, according to Fulham, who presented the study at the 2007 SNM meeting.

The next stage for the investigative team will be to identify patients with residual disease after initial diagnosis and treatment. Earlier diagnosis should yield better outcomes, Fulham said.

The absence of a single accurate test has made early detection of ovarian cancer recurrence challenging, according to Dr. Sunit Sebastian, a research associate at Emory University in Atlanta. Postsurgical scarring can inhibit the efficacy of anatomic imaging and CA-125 levels can be normal despite recurrence.

While PET/CT can assess the tumor biology, normal physiologic activity in the bowel, ovaries, and ureters can result in false positives and negatives. Therefore, PET/CT should be used in combination with biochemical surveillance to detect early recurrence of ovarian cancer and improve survival, Sebastian said.