Are Prostate Cancer Bone Lesions Considered "Cold"?
No, prostate cancer bone metastases typically appear as "hot" lesions on bone scintigraphy, not "cold" lesions, because prostate cancer characteristically produces osteoblastic or mixed osteoblastic-osteolytic bone metastases that generate increased radiotracer uptake. 1
Why Prostate Cancer Lesions Are Usually "Hot"
Prostate cancer bone metastases are predominantly osteoblastic or mixed in nature, triggering reactive new bone formation that produces focal increases in tracer uptake on technetium-99m bone scans 1, 2
Bone scintigraphy detects the osteoblastic response to tumor, not the tumor itself directly—the radiotracer (99mTc-MDP) is taken up by active osteoblasts at sites of increased bone formation 1, 2
Radionuclide bone scans are highly sensitive to osteoblastic and mixed osteolytic-osteoblastic lesions such as those from prostate and breast cancer, making them appear as areas of increased radiotracer uptake ("hot spots") 1, 2
When "Cold" Lesions Occur (Rare in Prostate Cancer)
"Cold" lesions (photon-deficient areas) on bone scans are predominantly seen with purely osteolytic metastases from cancers like kidney, thyroid, and multiple myeloma—not typically prostate cancer 1, 3, 4
Bone scans are relatively insensitive for purely osteolytic lesions, with sensitivity as low as 62% in predominantly lytic disease, because these lesions lack the osteoblastic response needed for radiotracer uptake 1, 2
Historical case series show "cold" lesions occurred in only 1.8% of abnormal bone scans across various malignancies, and when present, they were more common in tubular and denser bones 4, 5
Clinical Implications for Prostate Cancer Imaging
The characteristic "hot" appearance of prostate cancer bone metastases makes conventional bone scintigraphy a reasonable screening tool for higher-risk patients (PSA >20 ng/mL or Gleason score ≥8) 1
However, bone scans have significant limitations: they image the body's response to tumor rather than the tumor itself, leading to the "flare phenomenon" where healing lesions can mimic progression 1, 2
More advanced imaging modalities are superior: 18F-sodium fluoride PET detects lesions before conventional bone scans become positive, and FDG-PET directly assesses metabolic activity of metastatic tissue 1, 2
Key Pitfall to Avoid
Do not assume a negative bone scan excludes bone metastases in prostate cancer—while prostate lesions are typically "hot," bone scans can miss early marrow-based metastases before they provoke sufficient osteoblastic response, and MRI has superior sensitivity (82-100%) for detecting these early lesions 1, 2