Incidental ovarian cysts: When to reassure, when to reassess, when to refer

MANAGING AN INCIDENTAL OVARIAN CYST OR CYSTIC MASS

Combining information from the history, physical examination, imaging, and blood work to assign a level of risk of malignancy is not straightforward. The clinician must weigh several imperfect tests, each with its own sensitivity and specificity, against the background of the individual patient’s likelihood of malignancy. Whereas a 4-cm simple cyst in a premenopausal woman can be assigned to a low-risk category and a complex mass with flow to a solid component in a postmenopausal woman can be assigned to a high-risk category, many lesions are more difficult to assess.

Several systems have been proposed for analyzing data and standardizing risk assessment. There are a number of scoring systems based on ultrasonographic morphology and several mathematical regression models that include menopausal status and tumor markers. But each has drawbacks, and none is definitively superior to expert opinion.^16,17,37,38

A 2012 systematic review and meta-analysis³⁹ calculated sensitivity and specificity for several imaging tests, scoring systems, and blood tumor markers. Some results are presented in Table 1.

The management of an ovarian cyst depends on symptoms, likelihood of torsion or rupture, and the level of concern for malignancy. At the lower-risk end of the spectrum, reassurance or observation over time may be appropriate. A general gynecologist can evaluate indeterminate or symptomatic ovarian cysts. Patients with masses frankly suspicious for malignancy are best referred to a gynecologic oncologist.

Expectant management for low-risk lesions

Low-risk lesions such as simple cysts, endometriomas, and dermoids have a less than 1% chance of malignancy. Most patients who have them require only reassurance or follow-up with serial ultrasonography. Oral contraceptives may prevent new cysts from forming. Aspiration is not recommended.

In 2010, the Society of Radiologists in Ultrasound issued a consensus statement regarding re-imaging of simple ovarian cysts.³³

In premenopausal women, they recommend no further testing for cysts 5 cm or smaller, yearly follow-up for cysts larger than 5 cm and up to and including 7 cm, and MRI or surgical evaluation for cysts larger than 7 cm, as it is difficult to completely image a large cyst with ultrasonography.

In postmenopausal women, if the cyst is 1 cm in diameter or smaller, no further studies need to be done. For simple cysts larger than 1 cm and up to and including 7 cm, yearly re-imaging is recommended. And for cysts larger than 7 cm, MRI or surgery is indicated. The American College of Radiology recommends repeat ultrasonography and CA125 testing for cysts 3 cm and larger but doesn’t specify an interval.³²

A cyst that is otherwise simple but has a single thin septation (< 3 mm) or a small calcification in the wall is almost always benign. Such a cyst should be followed as if it were a simple cyst, as indicated by patient age and cyst size.

There are no official guidelines as to when to stop serial imaging,^22,32 but a recent paper suggested one or two ultrasonographic examinations to confirm size and morphologic stability.¹⁹ Once a lesion has resolved, there is no need for further imaging (Figures 1–3).

Birth control pills for suppression of new cysts. Oral contraceptives do not hasten the resolution of ovarian cysts, according to a 2011 Cochrane review.40 Some practitioners will, nevertheless, prescribe them in an attempt to prevent new cysts from confusing the picture.

Aspiration is not recommended for either diagnosis or treatment. It can only be considered in patients at high risk who are not surgical candidates. Results of cytologic study of specimens obtained by fine-needle aspiration cannot reliably determine the presence or absence of malignancy.⁴¹ There is also a theoretical risk of spreading cancer from an early-stage lesion. A retrospective study has suggested that spillage of cyst contents during surgery in early ovarian cancer is associated with a worse prognosis.⁴²

From a therapeutic point of view, studies have shown the same resolution rate at 6 months for aspirated cysts vs those followed expectantly.⁴³ Another study found a recurrence rate of 25% within 1 year of aspiration.⁴⁴

Referral for medium-risk or indeterminant-risk ovarian masses

Patients who have medium- or indeterminaterisk ovarian masses (Table 3) should be referred to a gynecologist. Further testing will help stratify the risk of malignancy. This can include tumor marker blood tests, MRI, or CT, the addition of Doppler or 3D ultrasonography, serial ultrasonography, or surgical exploration.

If repeat ultrasonography is chosen, the interval will likely be 6 to 12 weeks. Surgery may consist of removing only the cyst itself, or the whole ovary with or without the tube, or sometimes both ovaries. Purely diagnostic laparoscopy is rarely performed, as direct visualization of a lesion is rarely helpful. Frozen section should be employed, and the operating gynecologist should have oncologic backup, since the surgery is performed to rule out malignancy.

In the case of a benign-appearing cyst larger than 6 cm, thought must be given as to whether it is likely to rupture or twist. Rupture of a large cyst can lead to pain and in some cases to hemorrhage. Contents of a ruptured dermoid cyst can cause chemical peritonitis. Torsion of an ovary can result in loss of the ovary through compromised perfusion. A general gynecologist can decide with the patient whether preemptive surgery is indicated.

Operative evaluation for high-risk masses

Patients with high-risk ovarian masses (Table 4) are best referred to a gynecologic oncologist for operative evaluation. If features are seen that indicate malignancy, such as thick septations, solid areas with blood flow, ascites, or other pelvic masses, surgery is indicated. The surgical approach may be through laparoscopy or laparotomy.⁴⁵ It should be noted that even in the face of worrisome features on ultrasonography, many masses turn out to be benign.

In 2011, the American Congress of Obstetricians and Gynecologists and the Society of Gynecologic Oncology issued new guidelines recommending oncologic referral of patients with high-risk masses. Elevated CA125, ascites, a nodular or fixed pelvic mass, or evidence of metastasis in postmenopausal women requires oncologic evaluation.²⁶ For premenopausal women, a very elevated CA125, ascites, or metastasis requires referral (Table 4).²⁶

Direct referral to a gynecologic oncologist is underutilized. A recent study found that fewer than half of primary care physicians said that they would refer a classic suspicious case directly to a subspecialist.⁴⁶ It is estimated that only 33% of ovarian cancers are first operated on by a gynecologic oncologist.⁴⁷

A 2011 Cochrane review confirmed a survival benefit for women with cancer who are operated on by gynecologic oncologists primarily, rather than by a general gynecologist and then referred.⁴⁸ A gynecologic oncologist is most likely to perform proper staging and debulking at the time of initial diagnosis.⁴⁹

Special situations require consultation

Ovarian cysts in pregnancy are most often benign,⁵⁰ but malignancy is always a possibility. Functional cysts and dermoids are the most common. These may remain asymptomatic or may rupture or twist or cause difficulty with delivering the baby. Surgical intervention, if needed, should be performed in the second trimester if possible. A multidisciplinary approach and referral to a perinatologist and gynecologic oncologist are advised.

Symptomatic ovarian cysts that may need surgical intervention are the purview of the general gynecologist. If the risk of a surgical emergency is judged to be low, a symptomatic patient may be supported with pain medication and may be managed on an outpatient basis. Immediate surgical consultation is appropriate if the patient appears toxic or in shock. Depending on the clinical picture, there may be a ruptured tubo-ovarian abscess, ruptured ectopic pregnancy, ruptured hemorrhagic cyst, or ovarian torsion, any of which may need immediate surgical intervention.

If a symptomatic mass is highly suspicious for cancer, a gynecologic oncologist should be consulted directly.

WHEN TO REASSURE, REASSESS, REFER

Ovarian masses often pose diagnostic and management dilemmas. Reassurance can be offered to women with small simple cysts. Interval follow-up with ultrasonography is appropriate for cysts that are most likely to be benign. If malignancy is suspected based on ultrasonography, other imaging, blood testing, or expert opinion, referral to a surgical gynecologist or gynecologic oncologist is recommended. If malignancy is strongly suspected, direct referral to a gynecologic oncologist offers the best chance of survival if cancer is actually present.

Reassure

• When simple cysts are less than 1 cm in postmenopausal women
• When simple cysts are less than 5 cm in premenopausal patients.

Reassess

• With yearly ultrasonography in cases of very low risk
• With repeat ultrasonography in 6 to 12 weeks when the diagnosis is not clear but the cyst is likely benign.

Refer

• To a gynecologist for symptomatic cysts, cysts larger than 6 cm, and cysts that require ancillary testing
• To a gynecologic oncologist for findings worrisome for cancer, such as thick septations, solid areas with flow, ascites, evidence of metastasis, or high cancer antigen 125 levels.