Ultrasonography Useful for Predicting Ovarian-Cancer Risk
By Will Boggs MD
NEW YORK (Reuters Health) - The ultrasonographic appearance of ovarian masses is strongly associated with a woman's risk of ovarian cancer, researchers report.
"Ovarian cancer is a frightening and devastating disease, and we want to be able to find ovarian cancer as early as possible to improve our chances of having a good outcome for a patient," Dr. Rebecca Smith-Bindman of the University of California, San Francisco, told Reuters Health by email.
Transvaginal pelvic ultrasonography frequently identifies ovarian masses, most of which are benign and reflect normal physiological processes. The prevalence of ovarian masses and their appearance and cancer outcomes in an unselected population of women remain unclear.
Dr. Smith-Bindman and colleagues sought to identify ultrasonographic features predicting with a high level of certainty that an ovarian mass is benign and thus does not require surveillance in a case-control study of 210 women with ovarian cancer and 71,883 women without ovarian cancer who underwent more than 118,000 pelvic ultrasonography exams in total.
Most women had normal ovaries. The most common abnormal finding was a simple cyst, which occurred in 23.8% of women younger than 50 years and 13.4% of women 50 years or older.
Only one of the 15,306 women with simple cysts was subsequently diagnosed as having cancer within three years, and this occurred in a woman who was at least 50 years old.
The most common finding in women diagnosed as having ovarian cancer was a complex cystic mass, found in 63.3% of those younger than 50 years and 55.9% of those who were older.
The identification of a complex cystic mass increased the likelihood of cancer approximately eight-fold in both the younger and older age groups, and the presence of a complex cyst with ascites in women 50 years or older increased the likelihood of cancer more than 74-fold (both significant increases).
Similarly, the presence of a solid mass increased the likelihood of cancer eight-fold in women younger than 50 years and 10-fold in those 50 years or older, the researchers report in JAMA Internal Medicine, online November 12.
Among women diagnosed as having complex cysts, the three-year risk of ovarian cancer was estimated at 9.4 to 11.0 cases per 1,000 women younger than 50 years and 65.2 to 429.8 cases per 1,000 women 50 years or older.
In contrast, the three-year risk of ovarian cancer in both age groups was less than one per 1,000 women in whom a simple cyst is identified.
Where only the size of the cystic mass could be determined (that is, not its appearance), there was no statistical increase in cancer risk until cysts were 7 cm or larger.
"It is very important that the ultrasound is done well, and that when ovarian masses are characterized a full assessment is made so that simple cysts can be differentiated from complex cysts - cysts that are solid, or have vascular flow, or mural nodules or thick septations," Dr. Smith-Bindman said. "Complex cysts may end up being benign as well, but may reflect malignant cancer and should not be ignored. This is particularly true if complex cysts are seen together with ascites."
"However, if an ultrasound is done well, and a simple cyst is identified, no further imaging is needed and no referral to a gynecologist is needed," she said.
"Simple cysts are extremely common findings and, I believe, should be considered normal findings and ignored," she said. "While simple cysts are sometimes associated with pain, the pain usually resolves. If the pain does not resolve, but persists, then the simple cysts may need to be treated. However, the cysts do not need to be watched or followed (which they often are) to make sure they do not turn into cancer - as we demonstrated that this is not a risk."
Dr. Deborah Levine from Beth Israel Deaconess Medical Center, in Boston, who wrote an invited commentary in the journal, told Reuters Health by email, "Over the past 2 decades the medical community has come to realize that: 1) simple cysts are common in postmenopausal women and 2) the most aggressive type of ovarian cancer does not arise from a simple cyst. However, it is hard to change practice based on a single study, even a large one such as this."
"I am currently heading up the group that is going to revise the Society of Radiologists in Ultrasound (SRU) consensus conference statement on adnexal cysts," she said. "Our main goal in this revision process is to reassure patients and clinicians that simple cysts are benign, and to raise the size limit where no follow-up is recommended. However, we are not yet at the point where we can completely ignore simple cysts."
"Ultrasound is an excellent modality for assessing adnexal cysts," Dr. Levine said. "We can use these data to reassure patients that if a simple cyst is found on an ultrasound examination, it is a benign finding."
Dr. Elizabeth J. Suh-Burgmann from The Permanente Medical Group, in Walnut Creek, California, who recently validated a tool for ultrasonography-based assessment of ovarian-cancer risk, told Reuters Health by email, "The standardization system I developed was motivated by my growing frustration, during 20 years of practice as a gynecologic oncologist, with seeing ambiguity in ultrasound reports lead to both delay in diagnosis of ovarian cancer as well as unnecessary surgery, in some cases with complications, for benign or transient abnormalities."
"The reality is that women are the only ones harmed by lack of standardization," said Dr. Suh-Burgmann, who was not involved in the new study. "Moreover, in my experience, when a woman is scared (that) she has ovarian cancer, even when she has a complication from the unnecessary surgery she had for a benign cyst, she is still happily relieved to not have cancer and thanks her surgeon."
"According to HCUP (Healthcare Cost and Utilization Project) there are over 100,000 oophorectomies (without hysterectomy) done annually in the US that reveal benign tumors or cysts (this is an underestimate, as it does not include oophorectomies done with hysterectomy, for which there are over 200,000)," she said. "In some cases these surgeries are driven due to anxiety over possible ovarian cancer."
JAMA Intern Med 2018.
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