What Tests Evaluate an Ovarian Mass for Cancer?

If your healthcare provider finds an ovarian mass after viewing an ultrasound, or feels one on an exam, what are the chances that what's been discovered is ovarian cancer?

To determine whether an ovarian mass is malignant, your healthcare provider may use a few different tests, including subjective assessment, your ultrasound results, and levels of the tumor marker CA-125.

Diagram of mass which is ovarian cancer
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How Can You Know if Your Ovarian Mass is Ovarian Cancer?

If you have a mass in the area where your ovaries are located, you may be feeling frightened in addition to very confused. What could it be? You may be feeling even more frightened as you realize your healthcare provider doesn't really know if your ovarian mass could be cancerous or not. Shouldn't she know? Is there something she isn't telling you?

To clear up one of your fears anyway, it is very common for physicians to be perplexed by a pelvic mass in the region of the ovaries (called an "adnexal mass" if you hear that term).

At the same time that practitioners may not have any idea if an adnexal mass in your pelvis could be cancer, the chance of being "wrong”—acting before getting a better idea—is equally concerning. There can be problems either way: The risk of inadequate surgery if you do indeed have a cancer, and the risk of unnecessary surgery and the potential for complications with that surgery if you don't have a cancer.


Understanding Ovarian Cancer Symptoms, Stages, and Treatment

Are You at Risk for Ovarian Cancer?

We do have an idea of who is most at risk for ovarian cancer, but this is mentioned mostly so that you don't dismiss your possible risk of ovarian cancer if you don't have any risk factors. There is a reason that ovarian cancer has been coined the silent killer. It often causes few symptoms until the cancer is quite advanced, and anyone, regardless of risk factors, may be at risk of developing the disease.

If you are postmenopausal, you are at a higher risk. Most ovarian cancers occur in older women, although it can occur in young women or even children. At the same time, adnexal masses in young women are common and frequently come and go. Cysts are common prior to menopause, whereas an ovarian mass which appears in a post-menopausal woman is less likely to go away on its own. Keep in mind, however, that even if you are past menopause, you could well have a mass which is not cancer.

Symptoms of ovarian cancer may include bloating and weight gain, pain during intercourse, or a change in bowel habits. Risk factors include obesity, having a family history of breast, ovarian, or colon cancer, and the prior use of some fertility drugs or hormone replacement therapies.

Importance of Knowing Whether an Ovarian Mass is Cancer

It is important to know whether or not an ovarian mass is cancer for your own peace of mind. But with ovarian cancer, in particular, knowing whether or not cancer may be present is more important than with many other cancers.

If surgery will be performed for an ovarian cancer, a surgeon needs to be ready for a long procedure. A careful surgery can have a direct effect on survival. At the same time, studies have found that complicated surgeries (cytoreduction surgery for ovarian cancer) have a better prognosis if performed by specialists in ovarian cancer (by gynecologic oncologists) in a center which performs a significant volume of these surgeries, rather than by general gynecologists who do fewer of these surgeries.

It is still far too common for a surgeon to realize that an ovarian cancer, which will require an intricate and lengthy surgery, is present only after surgery has started. 

Tests to Determine the Risk of Malignancy

Since it is so important to attempt to distinguish ovarian cancers from other ovarian masses prior to surgery, a 2016 study sought to evaluate the tools we currently have, and look at their ability to separate out the cancers from masses which are not cancer.

It's helpful to be aware of a few terms when looking at these study results. Sensitivity is a measure that is used to show how successful a test is in finding a cancer; how often it can correctly identify those people having a disease. For example, a test with a sensitivity of 90% would be able to find 90 out of 100 cancers.

It's important not to over-diagnose conditions as well, as an over-diagnosis can lead to unnecessary surgery and treatments. Specificity is a test that helps to explain how commonly over-diagnosis may occur with a test. Specificity asks the question, "How often, when a person does not have the disease, will the test be negative?"

Current Tests that may be used to evaluate an ovarian mass include:

  • Subjective assessment
  • Simple rules - International Ovarian Tumor Analysis (IOTA) simple ultrasound-based rules
  • LR2 - IOTA logistic regression model 2
  • Risk of Malignancy Index (RMI)

The following table shows the results comparing these four measures including their sensitivity and specificity scores.

Tests to Evaluate the Chance that a Mass is Ovarian Cancer

Test Sensitivity Specificity
Subjective assessment 93 percent 89 percent
Simple Rules* 93 percent 80 percent
LR2* 93 percent 84 percent
Risk of Malignancy Index 75 percent 92 percent

*International Ovarian Tumor Analysis (IOTA) simple ultrasound-based rules (simple rules) and IOTA logistic regression model 2 (LR2)

The conclusion of the most recent studies is that a combination of subjective assessment plus simple rules may give the best estimate of whether or not an ovarian mass is cancer.

Risk of Malignancy Index for Ovarian Cancer

Many healthcare providers use the Risk of Malignancy Index (RMI) either alone or combined with "subjective assessment" and ultrasound findings to help sort out ovarian masses. There are several versions of the RMI, and all of them predict the risk of malignancy (risk that the mass is cancerous). This version has been tested several times by different researchers over the years.

There are three main factors used when determining the RMI. These include:

  • Age
  • Level of CA-125, a tumor marker 
  • Ultrasound score - Ultrasounds look for many findings including the general appearance of an ovarian mass, whether it is cystic or solid, and the presence of septations (areas of the mass that are divided by membranes). One point is assigned for each of the following: a multilocular cyst (sort of like a cluster of large grapes), solid areas, evidence of spread (metastases), abnormal free fluid (ascites), or masses on both ovaries.

Risk of Malignancy Index Formula

The basic formula for the risk of malignancy index (RMI) is:

RMI = U x M x serum CA-125 level

  • U represents the ultrasound score, from 0 to 5.
  • M is a menopause score where 1 is assigned to those who are premenopausal, and 3 is assigned to those who are post-menopausal.
  • The last factor is the numeric value of your CA-125 level; a value of 35 or lower is considered normal.
  • You simply multiply the U, M and CA-125 values to get RMI.

Understanding Your Risk of Malignancy (RMI) Score

An RMI score greater than 200, calculated in this fashion, is considered suspicious. If it exceeds 250, the chance that what you have is cancer is very high. However, the keyword is “chance.” Remember that this index helps sort things out, but does not prove one way or the other whether or not you have cancer for sure.

For example, if you are under 50 and have endometriosis, or have other reasons for CA-125 to be elevated, the RMI may be falsely high. Therefore, you may not have cancer. On the other hand, some cancers do not produce CA-125, so the RMI may be falsely low.

Next Steps in Evaluating Possible Ovarian Cancer

Your healthcare provider may use one or more of the tests above to try and determine the chance that your ovarian mass is a cancer. Determining this ahead of time can help you know whether or not a gynecologic oncologist should be available for your surgery. The more likely your mass is to be cancer, the more important this will be.

Ovarian Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

Limitations of Ovarian Mass Evaluation Techniques

It's important to note that there are limitations to even the best tests used to predict whether or not an ovarian cancer may be present. You and your healthcare provider will need to combine the results of any of these tests with other information, such as your symptoms and any risk factors you have for ovarian cancer. In other words, it is important to look at you as a person, rather than any specific numbers when deciding upon the next steps in evaluation in treatment.

Coping if You Have a Suspicious Ovarian Mass

It's important that you have a thorough discussion with your healthcare provider if you have an ovarian mass. Based on improved outcomes among those who have ovarian cancer surgery in which a gynecologic oncologist is present, as well as better results in centers which perform more of these procedures, a second opinion with a gynecologic oncologist may be wise no matter the results of any tests or risk factors.

Take time to learn about your condition. Ask for and accept support from those around you. The risk of dying from ovarian cancer is still far too high, and being your own advocate in your care is one thing you can do yourself which has the potential to improve your outcome.

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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