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Unilocular Ovarian Cysts in Postmenopausal Women: Surgery vs Expectant Management
By David M. Gershenson, MD
When I was a resident in obstetrics and gynecology in the mid-1970s, and well beyond, the dogma was that any ovarian cyst or mass in a postmenopausal woman was abnormal and required surgical resection. Postmenopausal women weren’t supposed to have ovarian cysts, and the possibility of cancer was looming largely, Of course, at that time, ultrasound was only beginning to be used in clinical practice, and then, almost exclusively in the practice of obstetrics.
Even with the advent of gynecologic sonography, however, it took almost 25 years to accumulate enough experience with postmenopausal cystic ovarian masses to begin to formulate management and treatment guidelines. This odyssey was also facilitated by the increasingly liberal use of computerized tomography and the discovery of the tumor marker, serum CA 125, in the early 1980s. In 2003, we have incontrovertible evidence that the vast majority of postmenopausal women with unilocular ovarian cysts up to 10 cm in diameter do not require surgery. How did we arrive at that judgment?
With increasing use of pelvic sonography for evaluation of women with gynecologic complaints or adnexal masses, reports began to emerge in the early 1980s describing ovarian cysts in postmenopausal women. These reports documented the apparent low rate of malignancy associated with unilocular ovarian cysts.1-8 Of postmenopausal women with unilocular ovarian cysts < 5 cm, only 3 of 209 (1%) were found to have a malignancy. Of unilocular ovarian masses in the 5-10 cm range, 1 of 21 (5%) postmenopausal women had a malignancy, which turned out to be only a tumor of low malignant potential.
In 1998, Bailey et al reported their experience with the University of Kentucky Ovarian Cancer Project.9 The Kentucky group had screened 7705 asymptomatic postmenopausal women with transvaginal ultrasound and identified 256 women (3.3%) with unilocular cystic ovarian masses. This included 231 women with ovarian cysts < 5 cm and 25 women with ovarian cysts in the 5-10 cm range. Spontaneous resolution of these unilocular ovarian cysts occurred in 54.3% of women 50-60 years of age and in 23.9% of women older than 60 years of age. All of the 45 women with persistent unilocular ovarian cysts subsequently underwent either laparoscopy or laparotomy with resection of the ovarian masses. None had a cancer. The histology of the ovarian masses in these women included a serous cystadenoma in 32, paratubal cyst in 4, paraovarian cyst in 3, endometriotic cyst in 2, mucinous cystadenoma in 2, hydrosalpinx in 1, and peritoneal cyst in 1.
More recently, in the September issue of Obstetrics and Gynecology, 2 reports further strengthen the data regarding unilocular ovarian cysts in postmenopausal women. In an update of the Kentucky group, Modesitt et al10 reported on 15,106 asymptomatic women at least 50 years old who underwent transvaginal sonography from 1987 to 2002. With almost twice the numbers in the 1998 report, multiple screens per individual over time, and probable improved technology, they found a higher rate of unilocular ovarian cysts (in 3259 women, or 18%) and a higher rate of spontaneous cyst resolution (in 2261 women, or 69.4%). Furthermore, they noted that a septum developed in 537 (16.5%), a solid area developed in 189 (5.8%), and 220 (6.8%) persisted as a unilocular lesion. No woman in this study with an isolated unilocular cyst has developed ovarian cancer. However, 27 women were diagnosed with ovarian cancer, and 10 had been previously diagnosed with simple ovarian cysts. It is important to note that all 10 of these women developed another morphologic abnormality, experienced resolution of the cyst prior to developing cancer, or developed cancer in the contralateral ovary.
Nardo and colleagues,11 in a report from the Unietd Kingdom, conducted an observational study of 226 postmenopausal women with unilocular ovarian cysts < 5 cm who were followed up for a 5-year period. They noted no change in ovarian cyst diameter and serum CA 125 levels in 172 (76.1%) of the women. Fifty-four women had an increase in cyst diameter, of which 6 (11.1%) also had an increase in serum CA 125 levels. All 54 women with suspicious ovarian pathology and 84 without suspicious pathology underwent surgery. Two of the 54 women were diagnosed with stage IB, grade 1 serous carcinoma; both women had elevated serum CA 125 levels.
In summary, in postmenopausal women with unilocular ovarian cysts that do not change in their ultrasonic appearance and in whom serum CA 125 levels remain normal, expectant management appears to be most appropriate. The malignancy rate in this group of patients is exceedingly low, but never zero. It may be slightly higher in women whose cyst is 5-10 cm in diameter compared with those whose cyst is < 5 cm. According to the Kentucky study, a very high proportion of these cysts will resolve spontaneously.10 Indications for surgical intervention may include symptomatology, a rise in serum CA 125 levels, or a change in the sonographic characteristics to include a septum or solid area.
If an asymptomatic unilocular ovarian cyst is found in a postmenopausal woman with a normal serum CA 125, how often should she be screened? There is no clear answer. In the British study, patients had a repeat screen in 6 months and then annually thereafter. If one discovers a new unilocular ovarian cyst in a postmenopausal woman (in combination with a normal serum CA 125), my bias would be to repeat the ultrasound and serum CA 125 in 6-12 weeks, and then every 3-6 months ´ 2, and then every 6-12 months thereafter. This may be overkill, but only future studies will elucidate the optimal interval.
Dr. Gershenson is Professor and Chairman Department of Gynecology M.D. Anderson Cancer Center Houston
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