June 6, 2011 -- Ovarian cancer screening does not reduce disease-related deaths among average-risk women, but it does result in an increase in invasive medical procedures and associated harms. That’s according to findings from a large, long-awaited, government-funded trial.
Nearly 80,000 women were enrolled in the ovarian screening arm of the National Cancer Institute’s screening study, presented Saturday at the American Society of Clinical Oncology (ASCO) 2011 Annual Meeting.
Women screened annually and followed for up to 13 years died in similar numbers from ovarian cancer and other causes as women who were not screened.
Ovarian Cancer Screening
Ovarian cancer is among the most deadly malignancies and the fifth leading cause of cancer deaths among women in the United States.
Because symptoms, if they occur, are often attributed to other conditions, most women with ovarian cancer are diagnosed late in the progression of the disease.
If caught early, before the cancer spreads beyond the ovaries, the five-year survival rate for ovarian cancer is more than 90%, compared to only about 30% among patients with advanced disease.
“The hope had been that the screening protocol we used would lead to earlier detection and better survival, but that is not what we found,” says Christine D. Berg, MD, chief of the early detection research group of NCI’s division of cancer prevention.
Screening Included CA-125, Ultrasound
The women in the study had an average risk for cervical cancer and were between the ages of 55 and 74 at enrollment. Half the women received ovarian cancer screening and half did not.
The screening protocol included serum cancer antigen 125 (CA-125) blood testing for six years and transvaginal ultrasound for four years.
CA-125 is routinely used to follow tumor progression in women with ovarian cancer, but its value for screening has long been questioned because levels can rise with many other conditions, including endometriosis, pelvic inflammatory disease, and even menstruation and pregnancy.
Over the follow-up, which ended in late February 2010, ovarian cancer was diagnosed in 212 women in the screening group and 176 women who were not screened.
But there was no significant difference in deaths, with 118 and 100 deaths occurring, respectively, in the screened and non-screened women.
The number of deaths from all causes was also strikingly similar, with 2,924 deaths occurring among the screened women and 2,914 deaths occurring among the women who were not screened.
Screening: More Harm Than Good?
More than 3,000 women had additional evaluations based on the screening findings and about half of these women had exploratory surgery.
Surgery confirmed ovarian cancer in 388 women, but 1,080 women without cancer ended up having surgical procedures and 163, or about 15%, experienced serious complications as a result.
These complications included infection, bowel injury, and cardiovascular events, Berg tells WebMD.
In addition to being presented at the ASCO meeting, the study will appear in the June 8 issue of the Journal of the American Medical Association.
Gynecologic oncologist and pelvic surgeon Elizabeth A. Poynor, MD, of New York City’s Lenox Hill Hospital, calls the ovarian cancer screening trial results disappointing but not unexpected.
‘All Hope Not Lost’
Poynor says more frequent screening with CA125 and ultrasound may benefit women at high risk for developing ovarian cancer because of family history.
And major advances in ultrasound imaging in recent years may prove beneficial for screening all women.
“All hope is not lost for these tools or for ovarian cancer screening in general,” Poynor tells WebMD. “We may not know the best way to use them at the moment, but that doesn’t mean they should be thrown out.”
What Women Can Do
Ovarian cancer is often called the ‘silent killer,’ but there is a growing recognition that many women do experience symptoms when the disease is still highly curable, Poynor says.
The problem is that many of the symptoms are also common among women without ovarian cancer, including:
- Back pain
- Pelvic pain
- Abdominal bloating
- Urinary urgency
Studies suggest that these symptoms can be more severe or frequent early in the course of ovarian cancer and researchers are exploring ways to screen based on this recognition.
“Women need to know the early warning signs and symptoms of this disease, and they need to listen to their bodies,” Poynor says. “Symptoms that are persistent or different should be discussed with a health care practitioner.”
And it is important that women know their family history of ovarian and breast cancer to help their practitioner assess their risk.
Poynor says women with a family history of breast or ovarian cancer may want to consider testing to determine if they are genetically predisposed to develop the diseases.
She adds that high-risk and average-risk women who qualify for ovarian cancer screening trials should consider joining one.
“We need information, and these trials are the way we will get it,” she says.