What does prostate cancer metastasis look like on imaging studies such as Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI) scans?

From the Guidelines

Prostate cancer metastasis on imaging studies typically appears as areas of abnormal tissue density or signal intensity in bones, lymph nodes, or organs, with bone metastases being the most common site of distant spread. On CT scans, bone metastases often show as sclerotic (dense, white) lesions, particularly in the pelvis, spine, and ribs, though they can occasionally appear lytic (dark) 1. Lymph node metastases appear as enlarged nodes (typically >1 cm) in the pelvic and retroperitoneal regions. On MRI, bone metastases show low signal on T1-weighted images and variable signal on T2-weighted images, with enhancement after contrast administration 1. MRI is more sensitive than CT for detecting bone marrow involvement. Diffusion-weighted imaging (DWI) sequences on MRI can help identify metastases as areas of restricted diffusion. Visceral metastases to organs like the liver or lungs appear as focal lesions with different density/intensity compared to surrounding normal tissue. The radiographic pattern of metastasis helps guide treatment decisions and assess disease progression, with bone metastases being the most common site of distant spread in prostate cancer. The appearance can vary based on treatment history, with patients who have received hormonal therapy sometimes showing mixed or atypical patterns 1. Recent studies have shown that novel PET tracers, such as fluciclovine and choline, have greater sensitivity for detecting prostate cancer recurrence and metastases at low PSA values (<2.0 ng/mL) 1. Whole-body MRI has also been shown to be superior to choline PET/CT and bone scan for metastasis detection on a per-patient basis, with a pooled sensitivity of 97% (95% CI, 91% to 99%) 1.

Some key points to consider when evaluating prostate cancer metastasis on imaging studies include:

• Bone metastases are the most common site of distant spread in prostate cancer
• MRI is more sensitive than CT for detecting bone marrow involvement
• DWI sequences on MRI can help identify metastases as areas of restricted diffusion
• Visceral metastases to organs like the liver or lungs appear as focal lesions with different density/intensity compared to surrounding normal tissue
• Novel PET tracers and whole-body MRI have greater sensitivity for detecting prostate cancer recurrence and metastases at low PSA values. It is essential to consider the treatment history and clinical context when interpreting imaging studies for prostate cancer metastasis, as the appearance of metastases can vary based on prior therapies 1.

From the Research

Prostate Cancer Metastasis Imaging

Prostate cancer metastasis can be detected using imaging studies such as Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI) scans. The appearance of metastasis on these imaging studies can vary.

• Bone metastases from prostate cancer are commonly located in the spine, pelvis, shoulder, and distal femur 2.
• On MRI, bone metastases from prostate cancer can appear as osteoblastic, mixed, or inter-trabecular type lesions 2.
• Whole-body MRI (WB-MRI) is a sensitive and specific tool for detecting bone metastases from prostate cancer, with the advantage of not involving radiation exposure 2.
• The main metastasis sites identified in one study were located at femur (43.2%), lumbar sacral spine (39.7%), cervical spine (38.2%), and ribs (33.7%) 3.
• The types of bone metastases identified in another study were sclerotic (27.6%), lytic (5%), and mixed (21.1%) 3.

Detection and Diagnosis

The detection and diagnosis of prostate cancer metastasis can be challenging.

• The main cause for suspicion of bone metastasis is routine follow-up (53%), followed by pathological fracture (31%) 3.
• The specialist who most frequently suspects bone metastasis and refers patients for diagnostic assessment is an urologist (84.9%) 3.
• Accurate and regular follow-up is necessary for the early detection of bone metastasis, as suspicion of bone metastasis is motivated by pain symptoms only in a small percentage of patients with prostate cancer 3.

Molecular Mechanisms

The molecular mechanisms of prostate cancer bone metastasis involve the interaction between tumor cells and the bone microenvironment.

• The tumor microenvironment and bone microenvironment play a crucial role in tumor growth and bone metastasis 4.
• Different cell types, including osteoblasts, osteoclasts, adipocytes, endothelial cells, hematopoietic stem cells, and immune cells, engage with tumor cells to affect tumor behavior 4.
• The "seed and soil" hypothesis, hemodynamics, and bone-specific signaling interactions are some of the biological processes that contribute to the osteotropism of prostate cancer 5.