O-RADS Explained: Is My Cyst Low or High Risk?

An O-RADS score is not a cancer diagnosis. It is a category a radiologist assigns to an ovarian finding, based on how it appears on the scan, so that a standard next step can follow. It sorts the finding by how likely it is to be cancer, and it tells your doctor what to do about it.

What the O-RADS score on your ovarian cyst report actually is

O-RADS stands for the Ovarian-Adnexal Reporting and Data System. It is a reporting standard issued by the American College of Radiology, first published in 2019 and revised as the 2022 version, which was set out in the journal Radiology in September 2023. Adnexal means the ovary and the structures beside it, so the system covers findings on or next to the ovary rather than the ovary alone.

Its purpose is standardisation. Before it existed, two radiologists looking at the same ovary could describe it in different words, and the doctor reading the report had to work out how concerned to be from the phrasing. O-RADS gives them a shared vocabulary for what they see and a numbered category for what that appearance means, so that the same finding produces the same category in different hands.

The category is assigned by the radiologist who reports the scan, working from the images. Your gynaecologist does not assign it, and neither do you.

The part that matters most to you is the second half of the system, which is the part that patient articles usually skip. Each category carries a recommended next step. That is what the number is for. It is a management instruction written in shorthand, and it exists so that a standard, sensible action follows a given appearance rather than an improvised one.

My ultrasound report does not have an O-RADS score. Is that a problem?

No, and this is normal in India. O-RADS reporting is not universal in Indian radiology practice. Many competent centres, including large hospital radiology departments, report ovarian findings in careful descriptive prose without assigning a category at all. A report without an O-RADS number is a normal Indian report.

It is worth being precise about what this does and does not mean, because the conclusion women usually reach is wrong. The absence of a score does not mean your scan was inadequate, that a step was skipped, or that something was found and left unwritten. The radiologist looks at the same features either way: the wall, the contents, the compartments, any solid tissue, and the blood flow. Those observations are in your report. The category is a label applied on top of them, not an extra examination.

Your gynaecologist can assess risk from the description. That is what doctors did before the system existed and what many still do well.

If you would like the category anyway, ask your treating doctor whether it would change anything in your case. That is a reasonable question to ask. It is not a reason to book a second scan somewhere else.

What each O-RADS category means, and what usually happens next

One thing to hold in mind before you read this table: the categories are ordered, but they are not a linear scale, and the gaps between them are uneven. The risk figures below are the bands published in the 2022 version of the system, and they belong in this table, not in your head as a single number.

‍

O-RADS Category	What It Means in Plain Words	Approximate Risk That It Is Cancer	What Usually Happens Next
O-RADS 0	The scan could not be properly assessed, usually because the technical factors such as bowel gas or limited view made it difficult to interpret. It is a statement about the scan, not about the finding.	Not assigned. No risk is attached to this category.	A repeat scan, or a different type of scan, to get an adequate look.
O-RADS 1	A normal ovary. What was seen is a structure the ovary makes as part of its ordinary monthly cycle, such as a follicle or corpus luteum.	Not applicable. This describes a normal ovary rather than a lesion.	Nothing. There is no finding to follow up.
O-RADS 2	Almost certainly benign. The finding has one of the classic, well-recognised benign appearances and measures below roughly 10 cm. This category includes typical haemorrhagic cysts, endometriomas and dermoid cysts.	Under 1%	Usually no treatment. Some findings in this group are watched with a repeat scan, depending on the type and your circumstances.
O-RADS 3	Low risk. Either one of those same classic benign appearances is larger, or a finding with a single feature that is not quite typical, such as a vascular solid nodule.	1% to under 10%	Usually a further look rather than an operation. The 2022 update made follow-up with ultrasound the recommended route for findings in this category that are not already known.
O-RADS 4	Intermediate risk. The finding has features that are not explained by a benign pattern, such as several compartments containing solid tissue, or a projection growing into the cyst.	10% to under 50%	Assessment by a gynaecologist. Further imaging, usually MRI, is often used to characterise it better, and referral to a specialist service follows where indicated.
O-RADS 5	High risk. The appearance shows features associated with malignancy, such as substantial solid tissue with blood flow through it, or fluid in the abdomen, alongside the finding.	50% or higher	Referral to a gynaecological oncology service, which is the team that assesses findings in this category and plans what follows.

‍

The right-hand column describes the usual direction of travel, not a timetable. Intervals differ by centre and by individual circumstance, and your own report may carry a specific recommendation from the radiologist that sits alongside the category.

Source: Ovarian-Adnexal Reporting and Data System US v2022, American College of Radiology, published in Radiology, September 2023. Conservative management framing for the lower categories per RCOG Green-top Guideline No. 62, Management of Suspected Ovarian Masses in Premenopausal Women, November 2011.

What pushes an ovarian cyst into a higher or lower O-RADS category

The category is built from what the radiologist sees, not from a single measurement. Below is the direction each commonly reported feature tends to push it in, and where its full explanation is found.

‍

Feature Described on Your Report	Which Direction It Pushes the Category	Where the Full Answer Is
Simple and Unilocular	Usually pushes the assessment lower risk. One compartment, clear fluid, and a thin, smooth wall are reassuring features.	Simple vs Complex Ovarian Cysts
Complex	May push the assessment higher, but mainly means the scan needs closer characterisation. Many complex cysts are benign.	Complex Ovarian Cysts
Septated or Multilocular	May push the assessment higher as the number and nature of compartments increase, although many multilocular cysts are still benign.	Septated and Multilocular Ovarian Cysts
Solid Component or Mural Nodule	Can push the assessment higher and generally warrants more careful evaluation, particularly when the solid area has blood flow.	Complex Ovarian Cysts
Haemorrhagic	Usually does not independently increase concern when the appearance is typical of a haemorrhagic cyst, which is commonly benign.	Haemorrhagic Ovarian Cysts
Endometrioma	Usually does not independently indicate malignancy when the imaging appearance is typical of an endometrioma.	Chocolate Cyst and Endometrioma
Dermoid or Teratoma	Usually does not independently indicate malignancy when the imaging appearance is typical of a benign dermoid.	Dermoid Cysts of the Ovary
Blood Flow or Colour Doppler	The significance depends on where the blood flow is seen. Flow within a solid component is more concerning than minimal or absent flow.	Complex Ovarian Cysts
Free Fluid	Does not automatically indicate a high-risk cyst. Its significance depends on the amount, appearance, location and other suspicious findings.	Complex Ovarian Cysts

‍

Is O-RADS 3 the middle? Understanding what the numbers do and do not mean

No. Three out of five reads like halfway, and that intuition comes from exam marks rather than from anything in this system. O-RADS 3 is a low-risk category, and most findings assigned to it are benign.

The categories are ordered, but they are not evenly spaced. The step from 1 to 2 is small because both describe findings that behave exactly as expected. The step from 3 to 4 is large. It is the point at which the risk changes enough that the recommended action shifts accordingly, and the 2022 version of the system treats category 4 as the practical threshold at which a finding is considered potentially malignant. Going up by one number does not mean the risk has gone up by one step.

What the ordering does tell you is direction. A higher category always carries a higher risk than a lower one. The proportions between them are set out in the table above, and that is where they should stay, because a figure read alone loses the category it belongs to.

One further thing about the number is worth knowing. It describes a moment. A category is assigned to a scan taken on a particular day. Many findings settle, shrink or resolve, and a repeat scan can place the same ovary in a different category. That is the system working as intended, not the first report having been wrong.

Can two radiologists give the same ovarian cyst a different O-RADS score?

Yes, within limits, and it is better to know this than to discover it.

Agreement between readers using O-RADS is generally good. Validation work has found the system usable by radiologists with varying levels of experience, and the committee behind the 2022 update cited good agreement among readers as one reason for extending it. But agreement is not perfect. A study published in Radiology: Imaging Cancer in 2022, specifically examining large, complex adnexal cysts, found only fair agreement among readers on the ultrasound category for that group. Borderline findings are where disagreement lives.

It is also worth knowing that the risk bands themselves were not settled by opinion. They rest on a large body of prospective data, much of it built on the work of the International Ovarian Tumor Analysis group, whose descriptors underpin the O-RADS vocabulary, given here in the group's own spelling.

The practical consequence is the useful part. A category is not read on its own. Your doctor reads it alongside the description that produced it, any previous scan, and what is actually happening to you. If two scans have produced different categories, the resolution lies in the descriptions and the trend between them, not in deciding which number was correct.

What your O-RADS score does not tell you

The system answers one question. It is worth being explicit about the questions it does not answer, because a reassuring category is often read as a general all-clear.

It does not tell you whether the cyst is causing your symptoms. A category describes appearance. A cyst can look entirely benign and have nothing to do with the pain that led to the scan, or look entirely benign and be its cause.
It does not tell you whether the cyst needs surgery. The category recommends a next step, and for most findings that step is watching or a repeat scan. Whether anything is removed is your treating doctor's decision, made on the whole picture.
It does not tell you what the cyst is. The type sits in the descriptive part of the report. The category sorts that finding only by how likely it is to be cancer.
It does not tell you whether the cyst will affect your fertility. This is the largest gap of the four, and the one that matters most here.

That last point deserves its own paragraph. The almost certainly benign category explicitly includes endometriomas. So a woman can be told, correctly, that her cyst is almost certainly not cancer, while holding the cyst type with the greatest bearing on ovarian reserve and on planning a fertility cycle. Both statements are true at once.

O-RADS was built to answer a cancer question, and it answers that well. It says nothing about your eggs, your reserve, or whether a cyst should be dealt with before fertility treatment. Those are separate conversations, and they belong with a fertility specialist.

Can I work out my own O-RADS category from my report?

No, and neither can an AI assistant reading the same words.

Scoring is based on the images, not the report text. It depends on things assessed at the machine while the scan is happening: how many compartments a cyst has and where the divisions sit, whether a projection into the cyst is genuinely solid tissue or a clot, and the colour Doppler score, which is a graded assessment of blood flow made by the person holding the probe. A written report summarises those observations. It does not contain them in the form the category is built from.

This matters more now than it once did, because pasting a report into a chatbot has become the first thing many people do. The limitation is exactly the same. An assistant works from a summary, and a confident answer built on incomplete input is still incomplete. It will produce a category. Neither you nor it can tell whether that category is the one a radiologist would have assigned based on the images.

The person who can tell you is the doctor holding the scan.

How an O-RADS score fits with your CA-125 result and your scan measurements

Four different items on your paperwork are routinely confused with one another. They answer different questions and they are read together, not weighed against each other.

‍

What It Is	What It Tells Your Doctor	What It Does Not Tell You
The O-RADS Category	How likely the finding is to be cancerous and what management or follow-up usually follows.	What type of cyst it is, whether it causes symptoms, or what it means for fertility.
The CA-125 Blood Result	A blood marker that is interpreted alongside the imaging findings rather than used on its own.	It cannot determine the diagnosis by itself. CA-125 can change for many reasons unrelated to cancer.
The Size in Centimetres	How large the finding is and whether it has changed compared with a previous scan.	Size alone does not determine how risky a cyst is. It contributes to the overall assessment but does not determine it by itself.
The Descriptive Wording	What the radiologist observed, including the cyst wall, internal contents, compartments and blood flow.	It is not a diagnosis on its own. The descriptive features are used to determine the appropriate risk category.

‍

You may also see other systems named, such as the risk of malignancy index or the IOTA rules. They answer the same question by a different route, and which a centre uses is local practice.

Where each of these is answered in full: CA-125 normal range, ovarian cyst size chart, reading your ovarian cyst ultrasound report, how ovarian cysts are diagnosed.

Does the same O-RADS score mean the same thing before and after menopause?

The category is assigned the same way, from the same features, regardless of which side of menopause you are on. What can differ is what follows it.

The reason is background risk, not anything in the scoring itself. The ordinary monthly activity of the ovary produces findings that come and go, and after menopause that activity has stopped, so a finding that would be expected in one context is not expected in the other. A structure counted as entirely normal in a menstruating ovary would not be described that way afterwards.

The practical difference sits in follow-up and in how readily a specialist opinion is sought. It is set by your doctor, not by the number.

Full answer: ovarian cysts after menopause.

When an ovarian cyst needs urgent attention, whatever the O-RADS score says

A low category is not a reason to wait out severe symptoms. This is the one place on this page where the number should be set aside entirely.

Seek urgent medical care the same day if you have:

Sudden, severe pain on one side of the lower abdomen
Fever alongside abdominal pain
Persistent vomiting with the pain
Fainting, or feeling faint on standing
Rapid swelling of the abdomen

‍

Two things can happen to a cyst that have nothing to do with how likely it is to be cancer. It can twist the ovary or rupture it. Both are mechanical events. A cyst in the most reassuring category can do either, and the O-RADS number offers no protection against them because it was never meant to measure that. Go to an emergency department rather than waiting for a scheduled review.

More on these two events: ovarian torsion and ruptured ovarian cyst.

What to ask your doctor about your O-RADS score

Five questions, phrased so you can ask them with the report in your hand.

What is the category on this report, and if there is none, what would you assign?
Which feature in the description put it in that category?
Does anything need to be repeated, and if so, roughly when?
Does this change anything if I am trying to conceive, or planning to?
If I have an older scan, does comparing the two change your answer?

‍

If you are holding a report and a number you have already searched, bring both to a review appointment, along with any earlier scan. A Cloudnine Fertility specialist can read the category alongside the description that produced it, and tell you what it does and does not change for you. The score answers a cancer question. The fertility question is separate, and worth asking properly.

‍