The CT flare response of metastatic @entity79 in XXXX .

@entity1 @entity263 @entity75 @entity79 @entity32621 @entity446 @entity1486
BACKGROUND: New or worsening @entity79 in @entity1 responding to treatment, known as the flare phenomenon is well described on @entity32621 bone scintigraphy, but to our knowledge has not previously been described on CT. The appearance of new or worsening @entity79 on CT in @entity1 with @entity263 may therefore be erroneously classified as disease progression. PURPOSE: To assess the incidence of @entity446 flare response at 3-month CT assessment in @entity1 with castrate-resistant @entity263 and to identify associated features that enable differentiation from progressive metastatic @entity79 at 3 months. MATERIAL AND METHODS: CT scans of 67 @entity1 with castrate-resistant @entity263 undergoing treatment were reviewed by a radiologist blinded to clinical outcome. Changes in number, size, and density of metastatic @entity79 were documented and Response Evaluation Criteria in Solid Tumours (RECIST) in soft tissue lesions, alkaline phosphatase, @entity1486 , and @entity32621 bone scans were used for correlation. RESULTS: Of the 39 @entity1 who had 3- and 6-month follow-up, eight @entity1 (21%) demonstrated an increase in number, size, or density of @entity75 on the 3-month CT scan despite improvement in PSA and soft tissue lesions. Three out of eight @entity1 (8%) maintained partial response/remained stable at follow-up and were defined as showing a flare response: in this group bone metastases evident on CT showed a qualitative and quantitative increase in density and no lesions faded at 3 months. In contrast, in all @entity1 who progressed at 3 months by PSA/RECIST criteria (n = 8) @entity79 showed a mixed pattern with some lesions increasing and others decreasing in density. CONCLUSION: The incidence of flare response of metastatic @entity79 evident at 3-month post-treatment CT in @entity1 with @entity263 undergoing systemic treatment is 8%. In @entity1 with falling PSA and stable/responding soft tissue disease at 3 months an increase in @entity79 in the absence of fading bone metastases can be interpreted as flare and is likely to represent a response.
