131I全身显像及血清甲状腺球蛋白测定在分化型甲状腺癌治疗随访中的作用

目的 评价131I全身显像联合血清甲状腺球蛋白(Tg)测定在分化型甲状腺癌(DTC)131I治疗随访中的临床应用价值。 方法 153例经手术病理确诊为DTC的患者,均在术后接受了1次以上的131I治疗,每次剂量为1.85~9.25 GBq,131I治疗前测定血清Tg,治疗5 d后进行131I全身显像。 结果 153例行131I治疗的DTC患者共行血清Tg和131I全身显像检查各为262次,其中55.6%(85/153)的患者的血清Tg水平与131I全身显像均异常,13.7%(21/153)的患者两者均为正常,30.7%(47/153)的患者两者结果不一致,不一致的47例患者经其他影像学检查证实19例131I全身显像异常的患者中有13例异常,28例血清Tg异常的患者中有25例异常。血清Tg诊断DTC转移的灵敏度和特异度分别为89%(110/123)和90%(27/30),而131I全身显像的灵敏度和特异度分别为79.6%(98/123)和80%(24/30)。 结论 DTC手术及131I治疗后,常规进行血清Tg测定和131I全身显像检查,对术后判定复发转移灶及制定最佳131I诊疗计划、评价131I疗效具有重要的临床应用价值。     

手术联合~(131)I治疗分化型甲状腺癌疗效探讨

目的探讨手术联合131I对分化型甲状腺癌的治疗效果。方法将160例分化型甲状腺癌(DTC)患者根据术后是否接受131I治疗分为观察组与对照组各80例。观察组给予手术+放射性131I治疗,对照组给予手术+优甲乐治疗,观察两组治疗情况。结果观察组首次"清甲"成功率为71.3%,甲状腺全切者首次"清甲"成功率显著高于次全切者(P<0.01)。术后131I治疗对颈部淋巴结转移患者总有效率为95.3%,肺转移患者为82.6%,骨转移患者为64.3%。服用131I后1周内不良反应发生率为38.8%(31/80),其中甲状腺全切者不良反应发生率显著低于次全切者(P<0.05)。随访至今,观察组复发转移发生率与患者存活率均显著优于对照组(P<0.05)。结论手术+131I治疗DTC可在术后有效清除残留甲状腺组织及残留的微小癌,同时可对颈部淋巴结转移及肺转移灶进行治疗,可降低复发及转移率,远期效果较好。     

131I全身扫描及18F-FDGPET/CT对分化型甲状腺癌术后转移诊治价值的比较

目的 探讨131I全身扫描(131I-WBS)及18F-FDG PET/CT在分化型甲状腺癌(DTC)术后转移诊治中的临床价值。资料与方法 27例DTC术后需行131I初治或复治的患者,检测其131I治疗前1 d的血清甲状腺球蛋白(Tg),在131I治疗后3~5 d进行131I-WBS。根据Tg与131I-WBS阴性或阳性的情况,将患者分成4种类型:Ⅰ型:Tg(+),131I-WBS(-);Ⅱ型:Tg(+),131I-WBS(+);Ⅲ型:Tg(-),131I-WBS(+);Ⅳ型:Tg(-),131I-WBS(-)。在131I-WBS后1周内行18F-FDG PET/CT。以术后组织病理学或至少6个月的临床和影像学随访结果为诊断病灶性质标准。分析131I-WBS及18F-FDG PET/CT对DTC术后患者转移的检出情况。结果 检查后发现有22例52处病灶发生了转移。131I-WBS检出其中的8例(36.4%)24处(46.2%)转移灶,与18F-FDG PET/CT检出的15例(68.2%)35处(67.3%)转移灶比较,差异均有统计学意义(χ2=4.46、4.74,P<0.05)。Ⅰ型13例(100.0%)、Ⅱ型5例(100.0%)、Ⅲ型3例(100.0%)、Ⅳ型1例(16.7%)发生了转移。Ⅰ型18F-FDG PET/CT的转移检出率(100.0%)与Ⅱ型(20.0%)、Ⅲ型(0%)比较,差异均有统计学意义(P<0.05),与Ⅳ型(100.0%)比较差异无统计学意义(P>0.05)。其中对13例Ⅰ型和1例Ⅳ型转移患者调整了治疗方案。结论 131I-WBS和18F-FDG PET/CT在DTC术后患者转移灶探测及决定下一步的治疗方案方面具有良好的互补性,特别是18F-FDG PET/CT在Tg(+)、131I-WBS(-)患者转移灶检出上更具有优势,有重要的临床指导意义。     

分化型甲状腺癌术后131I清甲效果的影响因素

利用131I清除甲状腺癌术后残留甲状腺组织(清甲)是分化型甲状腺癌(DTC)术后治疗中的重要步骤.清甲效果受诸多因素影响,包括口服131I的剂量、DTC的手术方式、术后甲状腺组织残留量、血清促甲状腺激素(TSH)与甲状腺球蛋白(Tg)水平、有无淋巴结及远处转移、手术距13I治疗时间的长短等.使用较大剂量131I进行清甲、采取甲状腺全切或近全切除术方式、131I治疗前较高水平的TSH,以及术后及时开始131I治疗等有助于提高清甲成功率.131I治疗前患者血清Tg水平偏高或存在转移灶,应适当加大131I治疗剂量.患者性别、年龄、病理类型等对清甲成功与否无明显影响.     

131 I治疗分化型甲状腺癌脑转移

目的：探讨131I治疗分化型甲状腺癌（DTC）脑转移的临床价值。方法：随访8例经131I治疗的DTC脑转移患者，通过临床症状，影像学检查及生存率分析，观察DTC脑转移131I治疗效果。结果：（1）131I一生存期2－35年，2001年底随访时均存活；（2）I期患者131I治疗5次（20．65GBq)，后CT示右小脑占位灶缩小，6次（23．61GBq)后CT示占位灶消失。（3）甲状腺双侧切除者，术后剩余甲状腺平均131I清除次数为2次，平均总清除剂量8．87GBq;单侧切除者，平均清除次数5．7次，平均总清除剂量29．98GBq，后者的清除次数和剂量均明显高于前者（P＜0．01）。（4）合并有肺和（或）骨转移灶仍见131I提取。结论：合并有肺和（或）骨转移的DTC脑转移者治疗难度增加，但术后131I治疗仍有效。     

甲状腺癌术后患者纵隔浓聚131I的临床分析

目的 探讨分化型甲状腺癌(DTC)手术及131I治疗后患者全身扫描(RxWBS)示纵隔浓聚131I的影像学特征.方法 收集1998-2004年收治的331例DTC术后患者共1183次131I治疗后5～7 d的RxWBS图像,所有患者至少接受2次131I治疗,结合甲状腺球蛋白(Tg)测定、其他影像学检查及临床随访结果分析纵隔浓聚131I的影像学特征及原因.结果 331例患者中最终诊断为纵隔浓聚131I者共34例,其RxWBS主要表现为纵隔点状、团块状、哑铃状或弥漫性放射性浓聚灶.其中甲状腺癌转移者21例,残留甲状腺组织8例,其余5例胸腺摄取131I患者年龄均＜45岁.结论 DTC术后患者纵隔浓聚131I可归因于甲状腺癌转移灶、甲状腺组织及胸腺摄取等.胸腺摄取131I是45岁以下甲状腺癌术后患者RxWBS假阳性的重要原因之一,血清Tg测定及131I SPECT/CT、CT增强扫描、MRI等有助于明确诊断.     

大剂量131I治疗312例分化型甲状腺癌转移灶的临床分析

目的：评价甲状腺癌（简称甲癌）转移灶患者多次大剂量^131I治疗疗效及其副作用。方法：①治疗方法：肺、骨转移乾每次口服^131I7.4GBq，淋巴结转移者每次口服^131I5.55GBq，2次治疗间隔4个月。②疗效判断：分治愈：为^131I显像阴性，血甲状腺球蛋白（Tg）降至正常水平；有效：血Tg转阴，^1321I显像仅见病灶缩小或减少或病灶吸^131I率下降；无效：血Tg高水平，^131I显像有新病灶出现或患者死亡。③副作用观察为对甲状旁腺功能及染色体畸变的影响。结果：①疗效：312例甲癌转移灶患者治愈35.9％（112例），有效60.2％（188例），无效3.8％（12例）。②副作用：8.6％的患者有甲状旁腺素（PTH）一过性下降，但无1例甲状旁腺减退症发生。治疗后外周淋巴细胞染色体出现多种畸变，部分患者的辐射耐受增强。结论：采用^131I多次大剂量治疗甲癌转移灶疗效佳，副作用小，不会发生甲状旁腺功能减退症等并发症。^131I治疗的适应证应扩大至手术病理检查发现淋巴结转移者。     

分化型甲状腺癌术后131I治疗的进展

甲状腺癌的发病率近年有增高趋势.南于甲状腺癌多以甲状腺结节首诊,在国内首次手术以肿瘤切除或甲状腺部分切除居多,占90.5%.原发灶再次手术肿瘤残留率达41.3%,颈淋巴结转移率72.8%.鉴于再次手术常伴喉返神经损伤和甲状旁腺功能减低等并发症,多数患者不愿再次手术.131I对术后剩余甲状腺组织可去除隐藏在残留甲状腺组织中的微小癌灶而降低甲状腺癌的复发率,也可破坏或抑制具有吸131I功能的转移灶.有利于长期随访评判及监测肿瘤的复发和转移情况.大量文献报道,低剂量(1.11GBq)131I对于分化型甲状腺癌单叶切除患者的首次去除率接近60%,重复治疗后的去除率超过90%.低利量131I治疗分化型甲状腺癌术后残余组织可以缩短住院时间,减少额外辐射作用,降低可能的不良反应,并减少患者的经济负担,以达到尽可能大的临床去除治疗效果.     

分化型甲状腺癌术后131I治疗的进展

甲状腺癌的发病率近年有增高趋势.南于甲状腺癌多以甲状腺结节首诊,在国内首次手术以肿瘤切除或甲状腺部分切除居多,占90.5%.原发灶再次手术肿瘤残留率达41.3%,颈淋巴结转移率72.8%.鉴于再次手术常伴喉返神经损伤和甲状旁腺功能减低等并发症,多数患者不愿再次手术.131I对术后剩余甲状腺组织可去除隐藏在残留甲状腺组织中的微小癌灶而降低甲状腺癌的复发率,也可破坏或抑制具有吸131I功能的转移灶.有利于长期随访评判及监测肿瘤的复发和转移情况.大量文献报道,低剂量(1.11GBq)131I对于分化型甲状腺癌单叶切除患者的首次去除率接近60%,重复治疗后的去除率超过90%.低利量131I治疗分化型甲状腺癌术后残余组织可以缩短住院时间,减少额外辐射作用,降低可能的不良反应,并减少患者的经济负担,以达到尽可能大的临床去除治疗效果.     

131Ⅰ显像及Tg值监测131Ⅰ治疗分化型甲状腺癌肺转移灶疗效的探讨

目的 探讨131I显像和Tg在监测131I治疗DTC肺转移患者疗效中的价值.方法 回顾性分析2007年6月至2011年8月收治的DTC肺转移患者50例,分别以131I显像、Tg、131I显像+Tg 3种方法监测及评价131I治疗DTC肺转移灶效果.比较131I显像肺转移灶呈弥漫性摄取和局灶性摄取患者治疗有效率的差异,计算有无肺外远处转移患者的治疗有效率.按治疗前及治疗中Tg水平将患者分为3组:＜ 100 μg/L、100 ～ 1000 μg/L和＞1000 μg/L组,比较3组治疗有效率差异.131I治疗前后Tg比较及不同组Tg间的比较采用秩和检验.独立二分类资料比较采用x2检验及Fisher确切概率法.结果 50例治疗前131I显像阴性2例,131I显像阳性48例.48例阳性患者中,治疗后11例显像阴性,24例病灶好转,有效率73％(35/48).肺转移灶呈131I弥漫性摄取与局灶性摄取者的有效率分别为69％(11/16)、75％(24/32),两者差异无统计学意义(x2=0.211,P ＞0.05).DTC肺外远处转移患者的疗效明显低于无肺外远处转移患者(x2 =3.868,P＜0.05),分别为3/10和70％(28/40).治疗后患者中位Tg水平由108.7 μg/L下降为78.3μg/L(Z=-0.698,P＞0.05).Tg升高患者17例,降低33例,按Tg判断治疗有效率66％(33/50).Tg＜ 100 μg/L组的疗效明显优于＞1000 μg/L组[80％ (20/25)与3/10,P=0.015],而100～1000 μg/L组与另外2组疗效间比较差异无统计学意义[67％(10/15),x2 =0.320,P＞0.05;P =0.111].综合131I显像及Tg结果判断,50例患者中6例临床治愈,25例好转,有效率62％ (31/50).结论 131I显像结合Tg是评价DTC肺转移131I治疗疗效的重要标准,Tg异常升高和肺外远处转移是DTC肺转移患者预后不良的因素.     

Data on repeated (131)I-WB scans and the incidence of positive Tg and negative (131)I-WBS in DTC patients from a 24 months study

We present data on repeated iodine-131 whole body scans ((131)I-WBS) in differentiated thyroid cancer patients (DTC) after surgery and (131)I remnant ablation and on increased thyroglobulin (Tg) with negative (131)I-WBS, in a retrospective study at our hospital. A total of 106 patients (91 female and 15 male) treated with (131)I for DTC met the inclusion criteria. The mean age of the patients was 45 years, age range 16-81 years. A total of 101 patients had complete 24 months follow-up following (131)I remnant ablation treatment. The mean (131)I dose administered after the first 6 months of follow- up was 3GBq while mean total dose was 4.9GBq, range 1.1-7.4GBq. Our results showed that at the end of the first 6 months post treatment, 58/101 patients had a negative (131)I-WBS. By the end of the 4th (131)I treatment at 24th months, the remaining 43 patients became negative for (131)I-WBS. We found increased Tg and negative (131)I-WBS in 2 of the 101 patients at the 24th months examination the so called Tg elevated negative (131)I-WBS (TENIS syndrome). The possible explanation of this syndrome is discussed. In conclusion, our study in DTC operated patients does not support the use of repeated diagnostic (131)I-WBS after an undetectable Tg because we found no Tg rebound in patients with negative (131)I-WBS, after 24 months of follow-up with serial measurements of Tg on and of suppression with L thyroxine.     

Sensitivity of 123I whole-body scan and thyroglobulin in the detection of metastases or recurrent differentiated thyroid cancer

Primary treatment of differentiated thyroid carcinoma consists of total thyroidectomy followed by ablation of thyroid tissue remnants and possible metastases by means of radioactive iodine. After complete destruction of remnants, metastases or recurrence can be detected by measurement of the serum thyroglobulin level as well as by radionuclide methods. Here we report on the sensitivity of diagnostic 123I scintigraphy and serum thyroglobulin measurement for tumour detection in patients with proven recurrence or metastases. Fifty-five patients who received their first high activity (1,850-5,550 MBq) of 123I therapy after total thyroidectomy and 131I ablation were included in the study. The thyroglobulin level was measured both during TSH-suppressive L-thyroxine therapy (Tg-on) and 4-6 weeks after L-thyroxine withdrawal (Tg-off, TSH>20 mU/l). Prior to treatment, whole-body scanning (WBS) was performed 24 h after the administration of 111-370 MBq 123I. The therapeutic activity of 1,850-5,550 MBq 131I was administered within 24 h after diagnostic scanning. The mean interval between 131I therapy and post-therapeutic WBS was 8.6 days (range 3-15 days). The sensitivity of WBS, Tg-on and Tg-off was 75%, 82% and 98%, respectively. The overall sensitivity of the combination of Tg-on with WBS and of Tg-off with WBS was 95% and 100%, respectively. In 12 out of 51 cases either Tg-off or Tg-on or both Tg-on and Tg-off levels were elevated while 123I-WBS was negative. More lesions were visible on the post-therapeutic 131I scan than on the corresponding diagnostic 123I scan (n=13). Tg values increased significantly (P<0.0001) after thyroid hormone withdrawal. Early treatment of distant metastases or tumour remnants of differentiated thyroid carcinoma is favoured and 131I treatment should also be considered in patients with a negative WBS but positive serum Tg level. The finding of a positive Tg-off level, which is clearly above the corresponding Tg-on value, is sufficient to make this decision. Additional diagnostic 123I WBS will not improve sensitivity.     

分化型甲状腺癌术后首次131I清甲效果影响因素的分析

目的 探讨分化型甲状腺癌（DTC）患者术后首次行131I清甲治疗疗效的影响因素。 方法 回顾性分析2013年4月至2022年3月于河北医科大学第四医院行DTC全切或近全切术后首次行131I 治疗的159例患者的临床资料,其中男性51例、女性108例,年龄24~78（46.5±11.9）岁。将患者按首次行131I治疗的剂量（2.96 GBq、3.70 GBq和5.55~7.40 GBq）分为3组进行研究。按清甲成功的判断标准,即131I 治疗后（4±1）个月131I诊断性全身显像示甲状腺床无放射性浓聚,分析患者的性别、年龄、手术方式、131I治疗前血清甲状腺球蛋白（Tg）水平及促甲状腺激素（TSH）水平、131I治疗距离手术的时间、131I治疗剂量对清甲效果的影响。计数资料的组间比较采用χ2检验。 结果 159例DTC患者首次行131I清甲的成功率为70.4%（112/159）。2.96 GBq组的首次131I清甲成功率为58.3%（21/36）,3.70 GBq组为69.2%（63/91）,5.55~7.40 GBq组为87.5%（28/32）,3组间的差异有统计学意义(χ2=7.071,P<0.05) 。手术方式为全切的DTC患者的清甲成功率为74.2%（95/128）,高于近全切患者的54.8%（17/31）,且差异有统计学意义（χ2=4.502,P<0.05）。治疗前TSH水平≥30 mU/L患者清甲成功率为73.9%（99/134）,高于治疗前TSH水平<30 mU/L患者的52.0%（13/25）,且差异有统计学意义（χ2=4.844,P<0.05）。患者在性别、年龄、131I治疗前血清Tg水平以及131I治疗距离手术的时间之间的差异均无统计学意义（χ2=0.311~3.073,均P>0.05）。 结论 131I治疗剂量、手术方式、131I治疗前TSH水平是影响DTC全切或近全切患者清甲成功率的因素。     

The early detection of metastatic differentiated thyroid cancer using 131I total body scan and treatment with 131I

With the purpose of achieving early detection and performing 131I therapy for metastatic lesions of differentiated thyroid cancer, we studied the clinical findings in 132 patients who underwent 131I total body scanning (131I TBS) between 1981 and 1990. Metastatic lesions were detected only by 131I TBS in 24 (18%) of the 132 patients. Of the 49 patients treated with 131I for metastases, 27 (55%) underwent total thyroidectomy and then had their metastatic lesions treated by 131I less than one year later. In the remaining 22 patients (45%), the metastatic lesions were treated with 131I from 1 to 31 years (mean: 8.4 years) after the initial thyroidectomy. We determined the optimal timing of 131I TBS following radical thyroidectomy to be 3-4 weeks by sequential measurement of the serum thyroid hormones, TSH, and Tg, and determination of the 123I uptake in residual or metastatic cancer of the neck after thyroidectomy. 131I TBS with simultaneous serum Tg determination were performed in 52 patients with metastases. Scans were positive in 43 of the 52 (83%) and the serum Tg level was greater than 10 ng/ml in 46 of the 52 (88%). Serum Tg was elevated in 9 patients with negative scans, while low Tg levels were found in 6 patients with positive scans. 131I therapy was effective in 49 of the 65 treated patients (75%), including 5 cures. Two patients worsened and 6 died. These 8 patients were all older than 56 years of age. Post-therapeutic 131I TBS demonstrated unsuspected metastatic lesions in 7 patients and had a higher detection rate for metastatic lesions than diagnostic 131I TBS. We conclude that 131I TBS with simultaneous Tg determination should be performed to detect metastatic lesions in all patients following positively total thyroidectomy for differentiated thyroid cancer, and that 131I treatment should be given when positive 131I uptake is detected in metastatic or residual cancer.     

非高危分化型甲状腺癌低剂量和高剂量131I清甲疗效的分析

目的 研究应用低剂量（1.11 GBq）和高剂量（3.70 GBq）放射性131I清除非高危分化型甲状腺癌（DTC）术后残留甲状腺组织的疗效。 方法 回顾性分析行131I清甲治疗的63例非高危DTC患者的临床资料,采用Binary Logistic回归分析年龄、首次手术距清甲的时间间隔、甲状腺24 h摄碘率、血清TSH水平和清甲剂量对清甲疗效的影响;27例患者给予低剂量、36例患者给予高剂量的131I清甲治疗,采用Pearsonχ2检验分析低剂量和高剂量131I清甲疗效的差异,P < 0.05表示差异有统计学意义。 结果 63例非高危DTC患者中,清甲成功者46例（73.02%,46/63）、未成功者17例（26.98%,17/63）;Binary Logistic回归分析显示,131I清甲剂量是清甲成功与否的主要影响因素（Wald=6.42,P=0.011）;27例给予低剂量131I清甲患者中有15例清甲成功,36例给予高剂量131I清甲者中31例清甲成功,Pearsonχ2检验结果表明,高剂量131I清甲成功率（86.11%,31/36）明显高于低剂量（55.56%,15/27）（χ2=7.311,P=0.007）。 结论 在临床实践中,当残余甲状腺组织较少时,对于非高危DTC患者可考虑采用高剂量131I清甲治疗,提高一次清甲成功率。     

Impact of 131I diagnostic activities on the biokinetics of thyroid remnants.

Recent publications described many discrepant findings about thyroid "stunning" after the administration of (131)I diagnostic activities to patients with differentiated thyroid carcinoma. Stunning may play a major role in reducing the therapeutic efficacy of high (131)I activities given for ablation therapy. METHODS: Participation in a multicenter study to investigate differences in iodine biokinetics in the hypothyroid state and after the application of recombinant human thyroid-stimulating hormone enabled us to study quantitative changes in thyroid iodine biokinetics after the administration of 74 MBq of (131)I twice within 6 wk and an ablation activity of 3-4 GBq 7-12 d after the second diagnostic administration of (131)I in 6 patients. RESULTS: The uptake and half-life of the first 74 MBq of (131)I were significantly reduced to a mean of 44% and a mean of 51%, respectively, after the second diagnostic administration and further reduced to a mean of 40% and a mean of 30%, respectively, during ablation therapy. The residence times were reduced to 25% in the second dosimetric assessment and to 10% during therapy compared with the value in the first assessment. For one patient, an estimated absorbed dose as high as 38 Gy was found in the first diagnostic study. The mean dose for all patients after the first assessment was 15 Gy; after each further assessment, the dose was reduced according to the decrease in residence time. CONCLUSION: This study shows a severe impact of 74 MBq of (131)I on the biokinetics of thyroid remnants during subsequent radioiodine therapy.     

Is empiric 131I therapy justified for patients with positive thyroglobulin and negative 131I whole-body scanning results?

The long-term monitoring of patients with differentiated thyroid carcinoma (DTC) is essential throughout the patient's life after total or nearly total thyroidectomy followed by 131I remnant ablation and thyroid hormone suppression of thyroid-stimulating hormone (TSH). Sensitive surveillance for DTC recurrences and metastases includes radioiodine diagnostic whole-body scanning (DWBS) and measurement of serum thyroglobulin (Tg) levels after endogenous or exogenous TSH stimulation. Serum Tg levels during thyroid hormone withdrawal usually are correlated well with the results of DWBS. In general, Tg levels undetectable by DWBS suggest complete remission, whereas detectable or elevated Tg concentrations are suggestive of the presence of 131I uptake in local or distant metastases. However, DTC patients with a positive Tg test and negative 131I DWBS results (Tg+ DWBS-) have been observed in follow-up studies. The management of these cases begets controversy. METHODS: We electronically searched Medline (1966-2004.3), Embase (1984-2003), the Cochrane Library (2004, 2nd edition), CNKI (1994-2004), and CBM-DISC (1978-2004). We also manually searched the Chinese Journal of Isotopes, Radiologia pratica, and the Chinese Journal of Endocrinology and Metabolism. RESULTS: Ten serial observations and 3 nonrandomized controlled trials were found. The available data showed that of 314 patients who were treated empirically with 131I, 194 (62%) of 314 displayed pathologic uptake in the thyroid bed, lung, bone, mediastinum, and lymph nodes. In studies with Tg-on and Tg-off data, 171 (63%) of 271 patients achieved a decrease in Tg. CONCLUSION: On the basis of data from recent studies, 131I therapy should be individualized according to clinical characteristics. More significantly, a decrease in Tg levels was achieved in 63% of DTC patients with Tg+ DWBS-, suggesting that 131I therapy does have a therapeutic effect when the Tg level is considered an index of tumor burden. The 62% positive posttherapy whole-body scanning results also indicated that a therapeutic dose of 131I could reveal approximately one half of previously undiagnosed lesions in some patients. Therefore, 131I therapy may be justified in patients with Tg levels of > 10 microg/L and DWBS- and who are at high risk of any recurrence.     

Possible explanations for patients with discordant findings of serum thyroglobulin and 131I whole-body scanning.

The long-term monitoring of patients with differentiated thyroid carcinoma (DTC) is essential throughout the patient's life after total or near-total thyroidectomy followed by (131)I remnant ablation and thyroid hormone suppression of thyroid-stimulating hormone (TSH). Sensitive surveillance for DTC recurrence and metastases includes radioiodine diagnostic whole-body scanning (DWBS) and measurement of serum thyroglobulin (Tg) after endogenous or exogenous TSH stimulation. Serum Tg levels during thyroid hormone withdrawal (Tg-off) are usually well correlated with the results of DWBS. In general, undetectable Tg levels with negative DWBS (DWBS(-)) suggest complete remission, whereas detectable or elevated Tg concentrations are suggestive of the presence of (131)I uptake in local or distant metastases. However, DTC patients with discordant results of Tg measurement and (131)I WBS have been observed in the follow-up study. Negative (131)I DWBS and a positive Tg test (DWBS(-) Tg(+)) are found in most of these cases. Positive (131)I DWBS and a negative Tg test (DWBS(+) Tg(-)), though of uncommon occurrence, has also been demonstrated in a small but significant number of cases. With this scenario, one should first attempt to uncover a cause for possibly false-negative or false-positive (131)I WBS or serum Tg. Explanations for the discordance are speculative but should be scrutinized when confronted with discrepant data in a given patient.     

Radioiodine-131 in differentiated thyroid cancer: a retrospective analysis of an uptake-related ablation strategy

In our hospital, a 24-h radioiodine-131 (¹³¹I) uptake-related ablation strategy is used in patients with differentiated thyroid cancer to destroy thyroid remnants after primary surgery. In this strategy, low doses of ¹³¹I are used, but data in the literature on its efficacy are conflicting. Therefore, we performed the present study to evaluate the clinical outcome of this ablation strategy. In this study, patients (n=235) were selected who underwent thyroidectomy for differentiated thyroid cancer, followed by an ablative dose of ¹³¹I. Approximately 6 months after ablation, treatment efficacy was evaluated using radioiodine scintigraphy and thyroglobulin (Tg) measurements. Successful ablation was defined as the absence of radioiodine uptake in the neck region (criterion 1). Tg values were determined 3–12 months after ablation (criterion 2). Based on criterion 1, unsuccessful ablation was found in 43.0% of cases. Pre-treatment uptake values were statistically significantly lower (P=0.003) in successfully ablated patients (mean 5.4%) than in unsuccessfully ablated patients (mean 8.2%). Based on criterion 2, unsuccessful ablation was found in 52.4% of patients. The uptake-related ablation strategy, using low doses of ¹³¹I, shows a relatively high treatment failure rate. Based on these results it is suggested that a lower ablation failure rate could be achieved by applying higher ¹³¹I doses in the ablation of thyroid remnants in differentiated thyroid carcinoma patients. In the case of lymph node metastases a further dose adjustment may be advisable.