Eriksson B, Bergström M, Lilja A, Ahlström H, Långström B, Oberg K
Department of Internal Medicine, Uppsala University, University Hospital, Sweden.
Acta Oncol. 1993;32(2):189-96. doi: 10.3109/02841869309083911.
Positron emission tomography (PET) makes it possible to study effects of medical treatment in vivo. Carcinoid tumors with liver metastases, especially those of midgut origin, produce serotonin via the precursors tryptophan and 5-hydroxytryptophan (5-HTP) and this overproduction contributes to the clinical symptoms of the carcinoid syndrome. Seven patients with histopathologically verified neuroendocrine tumors and liver metastases, five of whom with ileal carcinoids, one a lung carcinoid and one an endocrine pancreatic tumor, were included in the study. All patients had elevation of urinary 5-HIAA with the exception of one patient with a solitary liver metastasis of midgut origin. After an intravenous injection of 11C-5-HTP, PET was performed and the uptake of radioactivity in tumor tissue, normal liver and plasma were compared. All patients with elevated urinary 5-HIAA and also the patient with a solitary liver metastasis and normal urinary 5-HIAA had high accumulation and signs of a high rate of binding of 5-HTP in the liver metastases. The uptake was relatively homogeneous in midgut carcinoid liver metastases but in large necrotic metastases the radioactivity was localized to the periphery. In three patients PET examination was repeated after 3 months of interferon treatment and in agreement with circulating tumor markers and ultrasonography the uptake of 5-HTP was unchanged. Another patient who received the somatostatin analog somatuline progressed on treatment and accordingly the uptake of 5-HTP also increased. The experience with PET in neuroendocrine gastrointestinal tumors is very limited. Our results so far indicate that 5-HTP can be used to visualize serotonin-producing neuroendocrine tumors and furthermore it might prove to be of value to monitor the effects of treatment, possibly also as an early predictive test of the outcome of treatment.
正电子发射断层扫描（PET）使在体内研究医学治疗效果成为可能。伴有肝转移的类癌肿瘤，尤其是那些起源于中肠的肿瘤，通过色氨酸和5-羟色氨酸（5-HTP）前体产生血清素，这种过量产生导致类癌综合征的临床症状。本研究纳入了7例经组织病理学证实的神经内分泌肿瘤并伴有肝转移的患者，其中5例为回肠类癌，1例为肺类癌，1例为内分泌胰腺肿瘤。除1例有中肠起源的孤立性肝转移患者外，所有患者尿5-羟吲哚乙酸（5-HIAA）均升高。静脉注射11C-5-HTP后，进行PET检查，并比较肿瘤组织、正常肝脏和血浆中放射性的摄取情况。所有尿5-HIAA升高的患者以及1例有孤立性肝转移且尿5-HIAA正常的患者，其肝转移灶中5-HTP均有高积聚及高结合率迹象。中肠类癌肝转移灶的摄取相对均匀，但在大的坏死性转移灶中，放射性定位于周边。3例患者在接受干扰素治疗3个月后重复进行PET检查，与循环肿瘤标志物和超声检查结果一致，5-HTP的摄取未发生变化。另1例接受生长抑素类似物索马杜林治疗的患者病情进展，相应地5-HTP的摄取也增加。PET在神经内分泌胃肠道肿瘤方面的经验非常有限。我们目前的结果表明，5-HTP可用于可视化产生血清素的神经内分泌肿瘤，此外，它可能被证明对监测治疗效果有价值，甚至可能作为治疗结果的早期预测性检测手段。
