Role of FLT PET in malignant pleural mesothelioma - prediction of response to chemotherapy

间皮瘤是一种肺部衬里的癌症。化疗通常用于治疗患者，以减轻他们的症状，提高他们的质量和生命长度。然而，并不是所有的患者都能从化疗中受益，而且大多数患者都会经历一些副作用。目前CT扫描被用来评估对化疗的反应，然而间皮瘤的生长方式使得测量反应变得困难。CT扫描在早期发现反应方面也不是很敏感--通常需要3到4个疗程(3-4个月)才能看到疗效。一种测试可以预测哪些患者在仅1个周期(3-4周)的化疗后受益，这将是一个巨大的优势，可能会使一些患者省去不必要的和潜在的毒性治疗。氟胸苷(Flt)是一种放射性示踪剂，注射到静脉后，被分裂的细胞摄取。肿瘤细胞通常比周围的正常细胞分裂得更活跃，因此当进行正电子发射断层扫描(PET)时，它将显示肿瘤是一个“热点”。Flt在肿瘤中的摄取量取决于DNA合成(细胞分裂活跃)的程度。化疗后，如果肿瘤有反应，预计肿瘤中的Flt量将会减少。这可以通过在第一个化疗周期后重复进行Flt PET扫描来评估。这项研究旨在评估间皮瘤患者化疗后1个周期内Flt摄取的变化对CT扫描所测量的疗效和患者预后(如生活质量和生存)的预测能力。人们希望，如果成功，这种类型的扫描可以通过早期选择那些可能从化疗中受益的人来改善患者的护理，并避免对那些无法从治疗中受益的患者产生不必要的毒性。

Mesothelioma is a cancer of the lining of the lung. Chemotherapy is often used to treat patients in order to reduce their symptoms and to improve quality and length of life. Not all patients however benefit from chemotherapy, and most patients will experience some side-effects. Currently CT scans are used to assess response to chemotherapy, however the way that mesothelioma grows makes measuring response difficult. CT scans also are not very sensitive in detecting response early - often 3 or 4 cycles of treatment (3-4 months) are required before benefit is seen. A test that could predict which patients were benefiting after only 1 cycle (3-4 weeks) of chemotherapy would be a great advantage, and may spare some patients unnecessary and potentially toxic treatment. Fluorothymidine (FLT) is a radioactive tracer that, after injection into a vein, is taken up by dividing cells. Tumour cells usually divide more actively than surrounding normal cells, and therefore when a positron emission tomography (PET) scan is performed it will demonstrate the tumour as a 'hot spot'. The amount of FLT uptake into the tumour depends on how much DNA synthesis (active cell division) is occurring. After chemotherapy, if the tumour responds it would be expected that the amount of FLT in the tumour will reduce. This can be assessed by repeating the FLT PET scan after the first cycle of chemotherapy. This study aims to assess the ability of the change in FLT uptake in mesothelioma after 1 cycle of chemotherapy to predict response, as measured on CT scans, and patient outcomes such as quality of life and survival. It is hoped that if successful this type of scan may improve patient care by selecting those who are likely to benefit from chemotherapy early and avoid unnecessary toxicity to patients who will not benefit from the treatment.