Sounding Out Cancer : Ultrasound a Promising New Use of Old Technology to Detect Ovarian Tumors

One month after Joann Bates’ mother died of ovarian cancer, the retired school secretary from East San Diego enrolled in an ultrasound screening program designed to detect the deadly cancer.

Screened three times, she felt confident she was healthy. But on the fourth examination, her doctor detected an early-stage tumor.

Bates, 60, was lucky; her tumor was detected promptly. Her mother’s tumor had been diagnosed at an advanced stage and it had killed the 80-year-old woman within four months.

By the time ovarian cancer is detected in most women, it is usually too late. More than two-thirds of ovarian cancer patients have widespread cancer at the time of their diagnosis. Despite advances in battling other cancers, the five-year survival rate for ovarian cancer has not significantly changed in two decades--only 38% survive.

To the frustration of doctors and patients, there has been no reliable screening test that can detect early-stage ovarian cancer.

Experts agree that doctors conducting a physical examination are unlikely to find a tumor until it’s advanced. And the existing blood test, called a CA-125, which detects elevated levels of a cancer cell byproduct, misses about half of all early-stage malignancies, doctors say.

As experts search for screening-test alternatives, one promising option has emerged: transvaginal ultrasound, or an internal vaginal probe. Federal health officials say this technology is so promising that a nationwide study will be launched next year.

At UC San Diego and other facilities where ultrasound testing is occurring, proponents say the technology could revolutionize diagnostic medicine, doing for ovarian cancer what the mammogram did for breast cancer and the Pap smear did for cervical cancer.

“Ultimately, ultrasound is going to mean early diagnosis of ovarian cancer and therefore improved treatment,” said Dr. Barbara Gosink, a UCSD professor of radiology and a driving force in the screening program here. “Women will live longer and we will pick up ovarian cancers earlier.”

Other experts agree that it is an auspicious prospect for a diagnostic tool, particularly as one of several that would be used to test for the deadly cancer.

“Clearly, it’s the most exciting breakthrough in ovarian cancer diagnosis we’ve had. It’s much more sensitive than blood tests and pelvic exams,” said Dr. Arthur Fleischer, chief of diagnostic sonography at Vanderbilt University.

In the United States, there are more than 20,700 new cases of ovarian cancer and 12,500 deaths every year. Across California, there will be an estimated 2,540 new cases of ovarian cancer in 1992 and it will kill 1,330, according to estimates by the American Cancer Society.

While doctors don’t recommend ultrasound for every woman, ultrasound proponents do suggest that women who are post-menopausal, have breast cancer, or have a family history of ovarian cancer, should get screened once a year. The screen is suggested for women who don’t have symptoms.

“If my mother had ovarian cancer, I would be getting screened,” Gosink said.

Beginning next year, the National Cancer Institute will test ultrasound screening during a 16-year trial involving 75,000 women at about 12 medical centers across the United States, said Dr. Barry Kramer, associate director of the NCI’s Early Detection and Community Oncology Program.

“We know (the blood test) by itself cannot do the job, so we need another technology,” said Kramer, who is part of the Division of Cancer Protection and Control. “We just don’t know enough about transvaginal ultrasound. But preliminary studies show it can pick up very early lesions.”

For the NCI trial, researchers will compare three screening techniques--pelvic examination, blood test, and ultrasound--on women between the ages of 60 and 74, because ovarian cancer tends to occur more often in that elderly age group, Kramer said. This trial will be part of a larger study of several cancers, including prostate, colon-rectum, lung, and ovary.

“We guesstimate that the combination of pelvic exam plus transvaginal ultrasound and CA-125 (blood tests) would yield a 35% decrease in mortality from ovarian cancer. To put things in perspective, a mammogram decreases breast cancer mortality by up to 30%.”

While this extensive study will answer a number of questions about the relatively new screening test, some doctors--including Gosink--say they are sufficiently encouraged by their own results, so they are not going to wait a decade to get the official verdict.

“Basically, it’s going to take 10 years before we know if it’s cost effective,” Gosink said. “I think the trial should be done. But in the intervening years, I think it’s reasonable to offer a screening program.”

In San Diego, two facilities now offer the ultrasound method: UC San Diego Medical Center and Scripps Clinic. In fact, Kramer estimates that fewer than 10 facilities nationwide offer transvaginal ultrasound as a screen for ovarian cancer. The sites that offer it include Los Angeles’ Cedars-Sinai Medical Center and Long Beach Memorial Medical Center.

At these facilities, doctors use an internal vaginal probe that provides a visual picture of the ovaries and uterus that is better than the traditional external abdominal probe. At UCSD, this visual image is combined with an imaging picture that also shows blood flow around the ovaries, which increases when cancer is present.

Ultrasound technology has traditionally been used to provide a window to the body’s inner workings. For instance, doctors employ it to determine the position of a pregnant woman’s unborn baby. It also has been used for years to look at tumors in other organs.

“It’s not cutting-edge technology. It’s cutting edge application of the technology,” Gosink said.

Part of the problem in detecting ovarian cancer has been that doctors are unable to examine or see the region well. Among young women, an ovary is about the size of a walnut. In menopausal women, who are considered at-risk for ovarian cancer, the ovary has shrunk to the size of an almond--making it very difficult to examine, Gosink said.

“With ultrasound, we can see ovaries at a size that’s smaller than can be felt on pelvic exams,” Gosink said.

The other problem with diagnosing ovarian cancer is that it does not produce symptoms until late in its development.

“This cancer spreads early and doesn’t cause much in the way of symptoms. The combination is deadly,” Gosink said.

In European studies, doctors using ultrasound were able to detect ovarian cancer that had not been picked up in pelvic exams.

But experts here urge caution, saying that the imaging technology is so delicate that physicians will be finding non-malignant cysts and growths. These common growths could create a number of false positives--as well as false negatives--in the screening test. And the potential for false readings could lead to unnecessary surgeries, experts say.

“If the test is indiscriminately used by people who are not skilled in performing it, there will be a lot of false positives and false negatives,” said Dr. Michael Crade, medical director of diagnostic ultrasound at Long Beach Memorial Medical Center. “In the proper hands, it does work reliably but the person doing it should be skilled in imaging. There are a number of imaging pitfalls. You have to be careful and not rush off to surgery.”

Because the color imaging ultrasound machines cost $250,000, doctors also are weighing whether the technology will be cost effective for widespread use. At UCSD, the ultrasound screening test costs $160.

Ultrasound is “very costly. Is it cost effective? Those are questions that have yet to be answered,” said Dr. Larry Platt, chairman of obstetrics and gynecology at Cedars-Sinai Medical Center and a UCLA professor of obstetrics and gynecology. “We are not yet ready to endorse that every women should be screened with ultrasound for ovarian cancer. We’re not yet sure it’s going to provide the information we are looking for.”

Platt and others also are pressing forward, trying out several possible screening tests. “We’re taking the approach that no one modality can pick it up,” he said.

One look at the survival rates explains the urgency that he and others feel.

If diagnosed and treated early, 85% of women stricken with ovarian cancer survive. But only 24% of all cases are detected at an early, localized stage, according to the American Cancer Society.

In the face of these odds, the ultrasound test offers one layer of reassurance.

“Women think, ‘It’s never going to happen to me.’ Well, I pray that it never happens to me,” said Shirley Freedman, a 56-year-old San Diego resident whose ultrasound test showed she didn’t have ovarian cancer.

“We just get so busy with life, we don’t take the time to take care of ourselves. We all have this innate fear of cancer,” she said. “But this (test) gives me a wonderful sense of security, because we don’t know what’s taking place in the body.”

When Joann Bates was wheeled into surgery in September, the doctors were unsure whether the growth found by the ultrasound test was actually a malignant cancer. Her CA-125 blood test showed no sign of malignancy. Her Pap smear and pelvic exam also were negative.

If the growth was benign, the surgery would last about one hour, Bates’ doctor told her. But Bates’ surgery lasted four hours as doctors sought to remove what turned out to be a four-centimeter malignant tumor.

Bates remembered her own mother when she came out of surgery. She remembered the feeding tube and the chemotherapy tube that doctors had inserted in the elderly woman. Yet when Bates awoke after her surgery, she had no such tubes.

She suddenly realized that the doctors had found and removed the tumor in time to save her life.

“I was just so grateful, so terribly grateful,” said Bates. “I felt I had been given another lease on life.”