Objectives: To evaluate the effectiveness of isotretinoin for improving 131 I uptake in recurrent/metastasized thyroid cancer with no/insufficient 131 I uptake. Design: Retrospective analysis of 25 patients treated between June 1999 and May 2001. Methods: 15 female and 10 male patients were given isotretinoin at 1 mg/kg for 3 months, followed by 131 I treatment. All patients received a 131 I scan 72 h after administration, thyroglobulin measurement, chest X-ray and ultrasound of the neck, and some patients underwent a 18 F-fluorodeoxyglucose (FDG) positron emission tomography ðn ¼ 14Þ and computed tomography scan of the chest ðn ¼ 11Þ: Results: In two out of 14 patients with raised thyroglobulin but no 131 I uptake, a slightly improved 131 I uptake was seen. In a further 11 patients an improvement of 131 I uptake of known lesions was desired or further non-131 I-accumulating lesions were known. A dosimetrically relevant improvement of uptake was seen in three of these patients.18 F-FDG uptake and thyroglobulin did not correlate with the success/failure of the isotretinoin treatment. Side effects including a strong 'sunburn', cheilitis, mucositis, conjunctivitis and raised transaminases occurred in two-thirds of patients. They were of an overall tolerable level and were reversible after isotretinoin had been stopped. Conclusion: From our clinical experience over a period of 2 years we conclude that the therapeutic effect of isotretinoin in thyroid cancer is certainly less than previously reported. An indiscriminate use of isotretinoin in all patients with otherwise untreatable thyroid cancer cannot be recommended.
Introduction: The role of positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) is currently under evaluation in urologic oncology. The aim of the present study was to investigate the use of [18F]FDG positron emission tomography ([18F]FDG-PET) in the detection and treatment control of malignant germ cell tumors compared to computed tomography (CT). Materials and Methods: Thirty-two PET studies and CT scans were carried out in 23 patients with histologically proven germ cell tumors (10 seminomas, 12 non-seminomatous germ cell tumors (NSGCT), 1 unclassified serologic recurrent disease) Lugano stage I–III. The scans were done either after initial diagnosis (n = 21) and/or within 3–45 days after chemotherapy was completed (n = 11). PET and CT were validated either by histology (n = 7) or clinical follow-up of 6–11 months after the last PET study has been performed (n = 16). Sensitivity, specificity, accuracy, positive and negative predictive values were determined for PET and CT. Differences between PET and CT for parameters of diagnostic value were evaluated by χ2 test. Results: Although not statistically significant, the sensitivity, accuracy and negative predictive value were higher for PET than for CT with respect to the detection of metastatic infradiaphragmatic and supradiaphragmatic lesions after initial diagnosis. The specificity and positive predictive value of PET and CT were comparable. After chemotherapy, PET was found to be significantly superior in specificity and accuracy compared to CT with respect to infradiaphragmatic lesions (p < 0.05). False-positive PET findings in supradiaphragmatic lesions after chemotherapy occurred in the case of inflammatory processes and resulted in a loss of specificity and accuracy compared to CT (p < 0.05). Conclusions: These preliminary results demonstrate [18F]FDG-PET to be a useful diagnostic tool for the initial staging and treatment control in patients with germ cell tumors. Possible advantages compared to CT, however, are as yet not clearly defined. The possibility of false-positive PET findings due to reactive supradiaphragmatic inflammatory processes early after chemotherapy have to be considered.
Radium (224Ra) is commercially available again for the treatment of ankylosing spondylitis. Twenty patients suffering from ankylosing spondylitis were treated with weekly intravenous (i.v.) injections of 1 MBq 224Ra for 10 weeks. Therapeutic effect was measured by C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and full blood count, as well as a completion of the Bath ankylosing spondylitis functional index (BASFI) questionnaire. Follow-up was done after three and six months. At the end of the treatment course pain and movement restrictions had improved subjectively in 12 out of 20 patients. These patients were also able to discontinue or reduce their analgesic or anti-inflammatory medications. Subjective improvement was well correlated with a reduction of CRP by 45% and BASFI by 73%. At the six-month follow-up, ten patients reported a lasting improvement, whereas two had suffered a relapse. A late therapeutic response after three months was seen in a single patient only. Patients who did not respond to radium had lower initial levels of acute-phase reactants and peripheral joint involvement. Only mild side-effects, e.g. temporary worsening of pain, were observed. Leukocytes and platelets reversibly decreased by 25%, respectively. It is concluded that 224Ra is an effective and safe treatment for ankylosing spondylitis.
Coincidence imaging with a dual-head gamma camera may offer a cost-effective alternative to dedicated PET. The aim of this study was to compare the diagnostic accuracy of coincidence imaging and PET in patients with differentiated thyroid cancer. Thirty-one patients were studied after thyroidectomy and radioiodine ablation. They were injected with a single dose of 300 MBq 18F-FDG. Scanning was performed on a dedicated PET system after 1 hr, and on a coincidence gamma camera after 4 hrs. Based on a lesion-by-lesion comparison, coincidence imaging and PET concurred in 69% of 118 lesions. Based on lesion size, concurrence was 96% in lesions larger than 1.5 cm, and 62% in those between 1 and 1.5 cm. Lesions smaller than 1 cm could not be identified with coincidence imaging. Identical staging was obtained with coincidence imaging and PET in 26/31 patients (84%). In four patients FDG accumulating lesions were shown by both the coincidence camera and the dedicated scanner, but not detectable with any other imaging means and were confirmed histologically on surgery. Although a coincidence camera is technically inferior to a dedicated PET scanner, it may provide clinically useful results in situations were a lesion of sufficient size and FDG uptake is to be expected, e.g. when evaluating a known lesion for malignancy.
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