Dose-response relationship in cyclophosphamide-treated B-cell lymphoma xenografts monitored with [(18)F]FDG PET

PURPOSE: Although [(18)F]FDG PET can measure therapy response sooner and more accurately than morphological imaging techniques, there is still some debate as to whether [(18)F]FDG uptake really reflects changes in the viable cell fraction. In this study changes in [(18)F]FDG uptake were investigated in a lymphoma model at several time-points after treatment and with different doses of chemotherapy. Data were analysed in terms of several parameters. METHODS: SCID mice were subcutaneously inoculated with 5x10(6) Daudi cells in the right thigh. One group was not treated (control group). The other groups received cyclophosphamide 75 mg/kg (low-dose group), 125 mg/kg (medium-dose group) and 175 mg/kg (high-dose group) on day 0. Sequential [(18)F]FDG small-animal PET (microPET) scans were performed on days 0, 2, 6, 9, 13 and 16 after treatment. The mean and maximum standardized uptake value (SUV(mean) and SUV(max)), metabolic tumour volume (Vol(metab)) and total lesion glycolysis (TLG) were calculated. RESULTS: A significant decrease in [(18)F]FDG uptake was observed on day 2 in the medium-dose and high-dose groups and on day 6 in the low-dose group, all preceding morphological changes. SUV(mean) and SUV(max) formed a plateau from day 6 to day 9, corresponding to the known influx of inflammatory cells. No obvious plateau was observed with TLG which was found to be the most sensitive parameter clearly differentiating the low-dose group from the medium- and high-dose groups early after therapy. CONCLUSION: [(18)F]FDG uptake was able to reflect the dose-response relationship for cyclophosphamide. TLG was the best parameter for dose-related response assessment in this tumour model.status: publishe

Molecular imaging of therapy response with (18)F-FLT and (18)F-FDG following cyclophosphamide and mTOR inhibition

PURPOSE: Evaluation and comparison of 3'-[(18)F]-fluoro-3'-deoxy-L-thymidine (FLT) and 2-[(18)F]-fluoro-2-deoxyglucose (FDG)-PET to monitor early response following both cyclophosphamide and temsirolimus treatment in a mouse model of Burkitt lymphoma. METHODS: Daudi xenograft mice were treated with either cyclophosphamide or temsirolimus and imaged with FLT-PET and FDG-PET on appropriate days post therapy inititiation. Immunohistochemical (IHC) studies (H&E, TUNEL, CD20, PCNA and ki-67) and DNA flow cytometry studies were performed. RESULTS: FDG tumor uptake decreased immediately after cyclophosphamide treatment while FLT-PET showed only a late and less pronounced decrease. A fast induction of apoptosis was observed together with an early accumulation of cells in the S-phase of the cell cycle, suggesting DNA repair. Temsirolimus treatment reduced both FDG and FLT tumor uptake immediately after therapy and resulted in a fast induction of apoptosis and G(0)-G(1) phase accumulation. CONCLUSION: FLT response was less distinct than FDG response and may be controlled by DNA repair early after cyclophosphamide. Nevertheless, FLT-PET was able to reflect decreased proliferation following temsirolimus

Dose-response relationship in cyclophosphamide-treated B-cell lymphoma xenografts monitored with [F-18]FDG PET

Although [(18)F]FDG PET can measure therapy response sooner and more accurately than morphological imaging techniques, there is still some debate as to whether [(18)F]FDG uptake really reflects changes in the viable cell fraction. In this study changes in [(18)F]FDG uptake were investigated in a lymphoma model at several time-points after treatment and with different doses of chemotherapy. Data were analysed in terms of several parameters.SCID mice were subcutaneously inoculated with 5x10(6) Daudi cells in the right thigh. One group was not treated (control group). The other groups received cyclophosphamide 75 mg/kg (low-dose group), 125 mg/kg (medium-dose group) and 175 mg/kg (high-dose group) on day 0. Sequential [(18)F]FDG small-animal PET (microPET) scans were performed on days 0, 2, 6, 9, 13 and 16 after treatment. The mean and maximum standardized uptake value (SUV(mean) and SUV(max)), metabolic tumour volume (Vol(metab)) and total lesion glycolysis (TLG) were calculated.A significant decrease in [(18)F]FDG uptake was observed on day 2 in the medium-dose and high-dose groups and on day 6 in the low-dose group, all preceding morphological changes. SUV(mean) and SUV(max) formed a plateau from day 6 to day 9, corresponding to the known influx of inflammatory cells. No obvious plateau was observed with TLG which was found to be the most sensitive parameter clearly differentiating the low-dose group from the medium- and high-dose groups early after therapy.[(18)F]FDG uptake was able to reflect the dose-response relationship for cyclophosphamide. TLG was the best parameter for dose-related response assessment in this tumour model

Single-center analysis of biopsy-confirmed posttransplant lymphoproliferative disorder: incidence, clinicopathological characteristics and prognostic factors

Hematopoietic stem cell and solid organ transplant recipients diagnosed with biopsy-confirmed posttransplant lymphoproliferative disorder (PTLD) at our institution from 1989 to 2010 were identified. Patient-, transplant- and disease-related characteristics, prognostic factors and outcome were collected and analyzed. One hundred and forty biopsy-proven cases of PTLD were included. Overall incidence in the transplant population was 2.12%, with heart transplant recipients carrying the highest risk. Most PTLDs were monomorphic (82%), with diffuse large B-cell lymphoma being the most frequent subtype. The majority of cases (70.7%) occurred > 1 year posttransplant, and 66% were Epstein-Barr virus positive. Following initial therapy the overall response rate was 68.5%. Three-year relapse-free and overall survivals were 59% and 49%, respectively. At last follow-up, 44% of the patients were alive. Multivariable analysis identified several classical lymphoma-specific poor prognostic factors for the different outcome measures. The value of the International Prognostic Index was confirmed in our analysis.status: publishe

The accuracy of positron emission tomography in the detection of posttransplant lymphoproliferative disorder

We investigated sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-fluorodeoxyglucose-positron emission tomography in 170 cases with suspected or biopsy-proven posttransplant lymphoproliferative disorder. All solid organ and hematopoietic stem cell transplant recipients who underwent an 18F-fluorodeoxyglucose-positron emission tomography scan between 2003 and 2010 in our center for the indication posttransplant lymphoproliferative disorder, were retrospectively reviewed and results were compared with tissue biopsy whenever possible. One hundred and seventy positron emission tomography scans in 150 patients were eligible for evaluation. In 45 cases, the patient had a biopsy-confirmed posttransplant lymphoproliferative disorder before positron emission tomography scanning and positron emission tomography was performed for staging purposes. In the remaining 125 cases, positron emission tomography was performed to differentiate between posttransplant lymphoproliferative disorder and other diseases. 18F-fluorodeoxyglucose-uptake was quantitatively expressed by calculation of maximum and mean standardized uptake value in the most intense lesion or, in the absence of attenuation corrected positron emission tomography scans, by comparing uptake in target lesion to liver and mediastinal uptake. We found an overall sensitivity of 89%, specificity of 89%, positive predictive value of 91% and negative predictive value of 87% for posttransplant lymphoproliferative disorder detection by 18F-fluorodeoxyglucose-positron emission tomography. In a subanalysis of the 125 scans performed for differentiating posttransplant lymphoproliferative disorder from other diseases, sensitivity, specificity, positive predictive value and negative predictive value were 90%, 89%, 85% and 93%, respectively. 18F-fluorodeoxyglucose-uptake in posttransplant lymphoproliferative disorder was generally high with a median mean and maximum standardized uptake value of 9.0 (range 2.0-18.6) and 17.4 (range 2.6-26.4). Posttransplant lymphoproliferative disorder often had an atypical presentation on positron emission tomography with high incidence of extranodal involvement. In conclusion, from these data, we can conclude that 18F-fluorodeoxyglucose-positron emission tomography is highly sensitive for detecting posttransplant lymphoproliferative disorder and has an excellent ability to differentiate posttransplant lymphoproliferative disorder from non-malignant diseases.status: publishe

Gynaecologic cancer complicating pregnancy: An overview

Cancer complicating pregnancy endangers two lives. Any approach should look at both maternal and foetal safety. Maternal prognosis will not improve by terminating the pregnancy. Imaging for staging purposes is possible, and sonar and magnetic resonance imaging are the preferred examinations. Abdominopelvic computed tomography exposes the foetus to the highest doses radiation and should be avoided. Provided a thorough maternal monitoring to ensure a stable uteroplacental blood flow and foetal oxygenation, surgical techniques that are used in non-pregnant patients are also safe for pregnant patients. Radiotherapy of the upper part of the body is possible during pregnancy, but during the third trimester the close distance may put the foetus at risk. Chemotherapy during the second or third trimester can be administered without increasing the incidence of congenital malformations. A systematic analysis, especially on the long-term outcome of the offspring after cancer treatment during pregnancy is still lacking. Here, we present a summary of issues related to the diagnosis and treatment of gynaecological malignancies during pregnancy. Firstly, we describe general diagnostic and cancer-treatment-related problems. In the second part, organ pathology including breast, cervical, ovarian, endometrial and vulvar cancer is discussed. (C) 2009 Elsevier Ltd. All rights reserved