From the Guidelines
A whole-body FDG-PET/CT scan is the most effective radiology test for detecting full body cancer, with a high sensitivity of 93% and specificity of 97% for detection of bone metastases, as demonstrated in a meta-analysis 1. This test combines positron emission tomography (PET) with computed tomography (CT) to provide both functional and anatomical information. During the procedure, you'll receive an injection of a radioactive glucose solution (typically F-18 FDG) that cancer cells absorb more readily than normal cells. After waiting about an hour for the tracer to circulate, you'll lie on a table that moves through a donut-shaped scanner for 20-30 minutes. The test can detect metabolically active cancer cells even before structural changes are visible on other imaging tests.
Some key points to consider when using FDG-PET/CT for full body cancer detection include:
- The ability to quantify tumor metabolic activity, which can serve as a prognostic indicator 1
- The detection of nonskeletal metastases, more frequently in the lung, but also lymph nodes and other organs 1
- The comparison with other imaging modalities, such as whole-body MRI, which may be less sensitive for some cancer types 1
It's worth noting that whole-body MRI is another option, particularly useful for patients who cannot receive radiation exposure, though it's less sensitive for some cancer types, as shown in a meta-analysis by Li et al. 1. These scans are typically ordered by oncologists or other specialists when there's suspicion of cancer or to monitor known cancer for spread. You'll need to fast for 4-6 hours before a PET/CT scan, and diabetic patients require special preparation to manage blood glucose levels. Insurance coverage typically requires specific clinical indications, and the tests are generally performed at specialized imaging centers or hospitals.
In terms of the technical aspects of the imaging protocols, the coverage of a whole-body FDG-PET/CT varies and usually extends either from skull base to thighs or skull vertex to feet, as noted in the study by Quartuccio et al 1. The inclusion of the entire lower extremities does not add additional benefit in identifying metastases, as shown in a study of FDG-PET/CT in patients with sarcoma and melanoma 1.
Overall, FDG-PET/CT is considered superior to Tc-99m bone scan and CT imaging in the detection of osseous metastases, making it the preferred choice for full body cancer detection 1.
From the FDA Drug Label
Fludeoxyglucose F 18 Injection, USP is indicated in positron emission tomography (PET) imaging for assessment of abnormal glucose metabolism to assist in the evaluation of malignancy in patients with known or suspected abnormalities found by other testing modalities, or in patients with an existing diagnoses of cancer The efficacy of Fludeoxyglucose F 18 Injection in positron emission tomography cancer imaging was demonstrated in 16 independent literature reports.
The radiology test to look for full body cancer is Positron Emission Tomography (PET) imaging with Fludeoxyglucose F 18 Injection, as it assists in the evaluation of malignancy in patients with known or suspected abnormalities found by other testing modalities, or in patients with an existing diagnosis of cancer 2 2.
- Key points:
- PET imaging with Fludeoxyglucose F 18 Injection is used to assess abnormal glucose metabolism.
- It is used to evaluate malignancy in patients with known or suspected abnormalities.
- The test has been demonstrated to be effective in 16 independent literature reports 2.
From the Research
Radiology Tests for Full Body Cancer
- The following radiology tests can be used to look for full body cancer:
- These tests have been shown to be effective in detecting primary and metastatic malignancies, including carcinomas of breast, lung, ovary, prostate, colon, urinary bladder, and gallbladder origin, as well as malignant melanoma, carcinoid, osteosarcoma, lymphoma, and spinal cord astrocytoma 3
Characteristics of Radiology Tests
- Whole-body FDG-PET has a sensitivity of 87% and a positive predictive value of 94% for detecting malignant lesions 3
- PET/CT and PET/MRI have been shown to be effective in detecting additional malignant findings and changing TNM staging in some cases 4
- PET/MRI has been shown to have a lower radiation dose compared to PET/CT, with a potential dose reduction of 79.6% 4
Limitations and Risks
- The presence of FDG uptake in benign inflammatory conditions may limit the specificity of whole-body FDG-PET 3
- Whole-body PET/CT scanning is accompanied by substantial radiation dose and cancer risk, with estimated lifetime attributable risk (LAR) of cancer incidence ranging from 0.163% to 0.514% for 20-year-old U.S. men and women 5
- The use of whole-body PET/CT or PET/MRI for cancer screening is not currently warranted due to the lack of reliable data and the potential for false positives and false negatives 6