Magnetic resonance imaging of the axial skeleton enables objective measurement of tumor response on prostate cancer bone metastases.
ABSTRACT There is currently no technique to image quantitatively bone metastases. Here, we assessed the value of MRI of the axial skeleton (AS-MRI) as a single step technique to quantify bone metastases and measure tumor response.
AS-MRI was performed in 38 patients before receiving chemotherapy for metastatic HRPCa, in addition to PSA, computed tomography of the thorax, abdomen, and pelvis [CT-TAP]; and Tc-99m bone scintigraphy. A second AS-MRI was performed in 20 patients who completed 6 months of chemotherapy. Evaluation of tumor response was performed using RECIST.
Only 11 patients (29%) had RECIST measurable metastases in soft-tissues or lymph nodes on baseline CT-TAP. AS-MRI identified a diffuse infiltration of the bone marrow in 8 patients and focal measurable metastatic lesions in 25 patients (65%), therefore, doubling the proportion of patients with measurable lesions. Transposing RECIST on AS-MRI in 20 patients who completed 6 months of treatment, allows the accurate estimation of complete response (n = 2), partial response (n = 2), stable disease (n = 5), or tumor progression (n = 11), as it is done using CT-TAP in soft tissue solid metastases.
MRI of axial skeleton enables precise measurement and follow-up of bone metastases as it is for other soft-tissue metastasis.
Article: RECIST revised: implications for the radiologist. A review article on the modified RECIST guideline.[show abstract] [hide abstract]
ABSTRACT: The purpose of this review article is to familiarize radiologists with the recently revised Response Evaluation Criteria in Solid Tumours (RECIST), used in many anticancer drug trials to assess response and progression rate. The most important modifications are: a reduction in the maximum number of target lesions from ten to five, with a maximum of two per organ, with a longest diameter of at least 10 mm; in lymph nodes (LNs) the short axis rather than the long axis should be measured, with normal LN measuring <10 mm, non-target LN >or=10 mm but <15 mm and target LN >or=15 mm; osteolytic lesions with a soft tissue component and cystic tumours may serve as target lesions; an additional requirement for progressive disease (PD) of target lesions is not only a >or=20% increase in the sum of the longest diameter (SLD) from the nadir but also a >or=5 mm absolute increase in the SLD (the other response categories of target lesion are unchanged); PD of non-target lesions can only be applied if the increase in non-target lesions is representative of change in overall tumour burden; detailed imaging guidelines. Alternative response criteria in patients with hepatocellular carcinoma and gastrointestinal stromal tumours are discussed.European Radiology 06/2010; 20(6):1456-67. · 3.22 Impact Factor