BERKELEY, CA (UroToday.com) - Prostate cancer is the most common solid cancer with an incidence of 214 cases per 1 000 men and is the second cause of cancer death in men. Prompt staging and diagnosis are important for treatment planning and prognosis; around 85% of patients who die of prostate cancer have bone compromise. Current EAU guidelines advise a bone scan as the chosen diagnostic test used to identify bone metastasis in newly diagnosed patients with PSA > 20 ng/mL, T3 – T4 disease and any Gleason 4.
We recently published an article on the usefulness of bone scan as a primary staging tool in newly diagnosed patients with prostate cancer. We found that although bone scan is a valuable tool for confirmation and monitoring of bone metastasis, on the 1 201 patients we retrospectively reviewed, only two patients may have had compromise outside of the area scanned in an abdomenal and pelvic MRI. From our cohort, 89% of patients that did not meet criteria for bone scan and still had a bone scan had no metastasis; furthermore, 64% of patients who did meet the criteria had a negative bone scan on presentation.
Our study was limited as it was done in a retrospective manner, and further, not all patients had all three imaging modalities (bone scan, MRI and CT scan). We are also unable to reassess the 2 patients with possible compromise outside the area scanned in the MRI.
In the past 20 years, magnetic resonance imaging (MRI) has developed rapidly, and we are currently performing more and more axial imaging of the prostate for staging and treatment planning. We believe that this test is sufficient and has shown a higher sensitivity and specificity than bone scan in the diagnosis of metastases because it also allows simultaneous and detailed evaluation of prostatic, periprostatic, and pelvic anatomy. Bone scan will, therefore, be unnecessary if the MRI or CT scan of the pelvis is negative for bone compromise. It is, of course, too soon to discard bone scan as a diagnostic tool, and more studies in this area will be needed in the future, including a prospective regional audit.
Unfortunately we currently don’t have an ideal imaging test that is not only affordable, minimally invasive, and that provides high specificity and sensitivity in the prediction of tumour staging, volume, and localization. Future research in this area includes imaging at high-field strength (≥ 3 tesla); novel spectroscopic markers of malignancy, such as polyamines and spermine; and MRI-guided biopsy and treatment. We expect further advances in imaging techniques avoiding unnecessary tests in newly diagnosed patients.
Written by:
Lina M. Carmona as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Clinical Research Fellow
King's College Hospital
Urology Department
London, England SE5 9RS
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