Ultrasound is one of the primary imaging tests to evaluate the ovaries. Ovarian cysts and masses are often diagnosed on ultrasound.
We can not tell with certainty whether an ovarian lesion is cancerous based on imaging alone. There are however features of the ovarian lesion that make it more suspicious for cancer.
There are times when ultrasound follow up is needed since we are not sure. Imaging with MRI and referral to a gynecologic oncology specialist is needed when the lesion is considered higher risk.
Can you see ovarian cancer on US?
Yes you can. We can sometimes see ovarian lesions that are benign appearing. In these cases we can make a specific diagnosis of a benign lesion like a hemorrhagic cyst.
We also identify lesions which are high risk for cancer. These patients will be referred to specialists called gyn-oncologist.
Many lesions fall into a low or intermediate risk for cancer. These lesions can further be evaluated with MRI and referral to a gyn-oncologist specialist.
What does ovarian cancer look like on US?
We can not tell for sure if a lesion is cancerous on ultrasound. Ovarian cancer has many appearances on ultrasound but certain features make the lesion higher risk.
Generally, a lesion that has more solid tissue or thicker septations is more suspicious for cancer. Finding ascites (fluid in the pelvis) and nodules outside the ovaries is suspicious.
Can you tell if a cyst is cancerous on us?
We can’t tell for sure but we can provide the level of risk based on the appearance of the cyst.
The American college of radiology has devised a risk stratification and management system for ovarian lesions called O-RADS.
Lesions are graded from 1 (normal ovary) to 5 (high risk >50% risk of cancer). Category 2 is almost certainly benign lesions (<1% risk), category 3 (low risk <10%) and Category 4 (intermediate 10-50% risk for cancer).
The criteria for grading are published online for each category including management. The more complex, larger, solid lesions become more suspicious.
Management of ovarian lesions based on their risk
Lesions graded as O-RADS 2 are generally left alone, followed up with another ultrasound test or MRI depending on the published criteria.
Lesions graded as O-RADS 3-5 are generally managed by further imaging with MRI and referral to a specialist.
Can ovarian cancer be missed on US?
Unfortunately yes. No imaging test or risk stratification system is perfect.
There is a risk of a cancer diagnosis being delayed.
There is a risk of an ovarian lesion being graded lower risk than it is.
It is possible that an ovarian lesion may not be seen when it is small.
What do you see when ovarian cancer is advanced?
We can see ascites or fluid, spread to the organs, and nodules in the abdominal cavity. There is often a mass in the pelvis representing the ovarian cancer.
Summary: ovarian cancer on ultrasound
Ovarian cancer can be seen on ultrasound tests. We can not be sure whether an ovarian lesion is cancer based on the ultrasound alone.
We can assign a risk to the ovarian lesion based on its appearance and published criteria like the O-RADS system described above. Often larger, more complex and solid lesions are more concerning.
Benign lesions can be left alone while those having any risk of malignancy are treated more aggressively. This can include follow up imaging for very low risk lesions or more aggressive imaging with MRI and referral to a specialist for management for lesions which have higher risk.