Indeterminate for Cancer on Radiology Reports: What It Means
If you see the phrase “indeterminate for cancer” on your CT scan, MRI, ultrasound, or PET scan report, it can feel alarming. The word cancer stands out. The word indeterminate feels uncertain. Together, they can create anxiety.
In many cases, “indeterminate for cancer” does not mean you have cancer. It means the imaging findings are not clearly benign and not clearly malignant. The radiologist cannot say for certain based on pictures alone. This article explains what that means, why it happens, and what usually comes next.
What Does “Indeterminate for Cancer” Mean?
When a radiologist calls a finding indeterminate for cancer, it means the imaging appearance does not have classic features of a clearly harmless condition, but it also does not have definite signs of cancer.
Imaging tests look at structure, shape, density, signal, and enhancement patterns. Some findings look very typical for benign conditions. Others have classic malignant features. But many fall in between.
Indeterminate means uncertain, not suspicious enough to diagnose cancer, and not clearly safe enough to ignore.
Why Do Radiology Reports Use Uncertain Language?
Radiology reports reflect what can and cannot be determined from imaging.
Scans are powerful, but they are not biopsies. A CT or MRI shows anatomy and patterns. It does not show individual cancer cells.
A lesion may be:
-
Small
-
Newly discovered
-
Mildly irregular
-
Slightly enhancing
-
Stable but not long enough
-
Atypical for common benign patterns
In these cases, the safest and most accurate description is indeterminate.
Radiologists are trained to avoid overcalling cancer and also to avoid falsely reassuring when something needs follow up.
Common Situations Where “Indeterminate” Appears
The phrase indeterminate for malignancy or indeterminate for cancer is common in imaging of:
Lung Nodules on CT Scan
Small lung nodules are very common. Many are scars, infections, or benign growths. If a nodule is small or newly seen, it may be labeled indeterminate until follow-up imaging shows stability.
Liver Lesions on MRI or CT
The liver often has benign findings like cysts, hemangiomas, or focal nodular hyperplasia. If enhancement patterns are not classic, the lesion may be described as indeterminate.
Kidney Masses on Imaging
Some kidney lesions have features of simple cysts. Others have some complex features that makes them indeterminate.
Lymph Nodes
Mildly enlarged lymph nodes can be reactive or malignant. Size alone does not always answer the question.
Bone Lesions
Many bone findings are benign variants. If imaging features are not clearly diagnostic, they may be described as indeterminate.
Does Indeterminate Mean High Risk for Cancer?
Not necessarily.
Many indeterminate findings turn out to be benign. The word does not mean probable cancer. It means not definitively characterized.
Risk depends on:
-
Your age
-
Personal cancer history
-
Smoking history
-
Family history
-
Size and growth of the lesion
-
Imaging characteristics
-
Location in the body
For example, a small stable lung nodule in a nonsmoker has a very different risk than a growing mass in a high-risk patient.
The report reflects imaging uncertainty, not a confirmed diagnosis.
Why Not Just Say It Is Probably Benign?
Radiology must balance accuracy with safety.
If a lesion does not meet strict imaging criteria for a benign diagnosis, labeling it benign can be misleading. Instead, radiologists use structured follow-up recommendations based on established guidelines.
For example:
-
Fleischner Society guidelines for lung nodules
-
LI-RADS for liver lesions
-
Bosniak classification for kidney cysts
-
BI-RADS for breast imaging
If a lesion does not meet criteria for a clearly benign category, it may remain indeterminate pending follow up.
What Happens After an Indeterminate Finding?
In most cases, the next step is one of the following:
Short-Term Follow-Up Imaging
Repeat CT or MRI in 3 to 12 months to look for growth or change. Stability over time strongly suggests benign behavior.
Advanced Imaging
MRI instead of CT, or PET scan, to better characterize tissue.
Comparison With Prior Studies
Older imaging may show that the lesion has been stable for years, which lowers concern.
Biopsy
If imaging and risk factors suggest concern, tissue sampling may be recommended.
Often, time is the most powerful diagnostic tool. Cancer typically grows. Benign findings usually remain stable.
How Radiologists Decide If Something Is Suspicious
Radiologists evaluate:
-
Size
-
Shape
-
Margins
-
Enhancement pattern
-
Calcifications
-
Fat content
-
Growth over time
-
Location
-
Surrounding tissue reaction
No single feature alone determines cancer. It is a pattern recognition process combined with clinical context.
When the pattern is incomplete or borderline, indeterminate is the most accurate description.
Is an Indeterminate Finding an Emergency?
Most are not.
Many indeterminate findings are incidental findings discovered during imaging for another reason. They are often small and asymptomatic.
If something requires urgent action, the report will usually state that clearly, often using words like suspicious, concerning, or recommend urgent evaluation.
Indeterminate usually implies we do not know for sure but there is no immediate danger.
How Patients Should Respond
If your report says indeterminate for cancer:
-
Do not panic.
-
Review the recommendation section.
-
Discuss the results with your doctor.
-
Ask about risk factors specific to you.
-
Follow recommended imaging intervals or further testing.
Skipping follow up can increase uncertainty. Completing follow up often resolves it.
Why Clear Communication Matters
Imaging findings exist on a spectrum. Not everything is black or white.
Radiologists use precise language to communicate uncertainty honestly. The term indeterminate protects patients from false reassurance and from premature cancer labeling.
In practice, many indeterminate findings are clarified over time and do not result in a cancer diagnosis.
Conclusion
“Indeterminate for cancer” on a scan means the imaging findings are not clearly benign and not clearly malignant. It reflects uncertainty based on imaging features, not a confirmed diagnosis of cancer.
Many indeterminate findings turn out to be benign, especially when they remain stable on follow-up imaging. The key is appropriate monitoring and communication with your doctor.
Understanding this term can reduce unnecessary anxiety and help you focus on the next step rather than the worst-case scenario.
References
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5135691/
https://www.jacr.org/article/S1546-1440(23)00613-0/fulltext
https://pubmed.ncbi.nlm.nih.gov/18625347/