Can a DEXA Scan Show Cancer or Just Bone Loss?

Does a DEXA Scan Detect Cancer?

No, a DEXA scan does not detect cancer.

Its purpose is to measure bone density and help diagnose conditions like osteopenia or osteoporosis, rather than identifying tumors or abnormal growths. DEXA scans don’t show enough structural detail to spot cancerous changes.

In rare cases, a DEXA might reveal an unusual drop in bone density in a specific area, but this finding is nonspecific and would require follow-up testing. On its own, the scan cannot distinguish between causes like aging, medication, or cancer.

Why a Bone Density Test Can’t Show Cancer

People sometimes assume that since bones are being scanned, a bone density test might also pick up signs of bone cancer or bone metastases. But that’s not how it works.

Here’s why:

• DEXA measures bone mineral density, not the shape, structure, or cellular health of the bone.
• It cannot visualize tumors, lesions, or abnormal growths.
• It doesn’t assess the activity or behavior of cells within the bone.

It also doesn’t produce images of the bone itself, so nothing cancer-related would visibly appear on the scan.

Which Scans Can Detect Bone Cancer?

While a DEXA scan can’t detect cancer, other imaging tests can. Here’s how bone cancer may appear on different types of scans:

• Bone scan: Cancer shows up as “hot spots,” where radioactive tracers gather due to increased bone activity.
• MRI: Can show clear images of tumors and how far they’ve spread into soft tissue.
• CT scan: Reveals abnormal growths, bone destruction, or structural irregularities.
• PET scan: Highlights areas of high metabolic activity, often indicating the presence of cancer.
• X-ray: May show tumors or bone destruction in more advanced cases.

Why You Might Get a DEXA Scan During Cancer Treatment

While DEXA doesn’t detect cancer, it’s still often used during or after cancer therapy. That’s because some treatments, especially for breast, prostate, and blood cancers, can cause bones to weaken over time.

You might get a DEXA scan if:

• You’re receiving hormone therapy or chemotherapy
• You’re on long-term steroids
• Your doctor wants to monitor for treatment-related osteoporosis

In this case, the DEXA scan helps protect your bones, not diagnose cancer. 

Bone Scan vs Bone Density Scan (DEXA)

Many people don’t realize there’s a difference between a bone scan and a bone density scan (DEXA). They sound nearly identical but serve entirely different purposes:

• Bone scan (nuclear medicine): Used to detect bone cancer, metastases, infections, and other abnormal bone activity.
• Bone density scan (DEXA): Measures how strong your bones are; it doesn’t look for cancer or abnormal growths.

The confusion is common, especially when people receive imaging results and aren't sure what kind of scan they had.