Pitfalls in lymph node staging with positron emission tomography in non-small cell lung cancer patients

BACKGROUND: The evidence of clinical value of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) in lymph node (LN) staging in non-small cell lung cancer (NSCLC) has been shown in numerous papers. However, few studies have assessed its limitations. The aim of the present study is to clarify clinico-pathologic factors responsible for false PET results. METHODS: From July 2000 through December 2001, 71 NSCLC patients underwent both FDG PET and surgical intervention at the National Cancer Center Hospital East, Chiba. Clinical records, computed tomographic (CT) scan findings, PET findings, and histologic findings were retrospectively reviewed. RESULTS: Sensitivity, specificity, accuracy in nodal staging for CT were 29, 83, and 65% and for PET were 39, 79, and 66%, respectively. There were 10 (14%) false-positive PET scans and 14 (20%) false-negative PET scans. The causative factors for false-positive PET scan were: (1) inflammatory conditions in seven patients; (2) PET mis-localization of an interlobar LN as a mediastinal LN in one patient; (3) inability to distinguish the endobronchial polypoid growth of a primary tumor from a lobar LN in one patient; (4) unknown in one patient. All false-positive LNs due to inflammatory conditions showed reactive lymphoid hyperplasia histologically. The causative factors for false-negative PET scan were: (1) limitation of spatial resolution of the PET scanner in 12 patients (maximum tumor focus dimensions in false-negative LNs ranging from 1 to 7.5 mm, with an average of 3.4 mm); (2) PET mis-localization of a mediastinal LN as a hilar LN in one patient; (3) weak FDG uptake by microscopic tumor foci due to necrosis with massive bleeding in a metastatic LN in one patient. CONCLUSIONS: Inflammatory conditions were most responsible for false-positive PET scans, and spatial resolution limitation of FDG PET was the causative factor of false-negative PET scans. Recognizing these factors in advance would be clinically helpful in accurate nodal staging with FDG PET.     

The role of 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) in the diagnosis of recurrence and lymph node metastasis of cervical cancer

The usefulness of positron emission tomography with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG-PET) in diagnosing recurrence and lymph node metastasis of uterine cervical cancer was evaluated as a preliminary study. The FDG uptake of 13 cervical cancer patients, including 4 patients with recurrence, was evaluated. The FDG uptake of the cervices of 5 patients who underwent PET studies for non-cervical tumors were used as control. In 2 patients who had undergone radical hysterectomy, we compared the diagnosis of lymph node metastasis based on FDG-PET and magnetic resonance imaging. The FDG uptake in the 9 primary cervical cancers was greater than that in normal cervices (p=0.025). Examination of the 4 recurrent tumors revealed a higher FDG uptake than that in normal cervices (p=0.0022). Metastatic lesions in lymph nodes showed an accumulation of FDG on the PET scan. In conclusion, FDG-PET may be an effective diagnostic tool for detecting recurrence and lymph node metastasis of uterine cervical cancers.     

The role of positron emission tomography in staging of non-small cell lung cancer

Correct staging of non-small cell lung cancer (NSCLC) is vital to undertake appropriate management and improve prognosis. Initial staging is usually performed with computerized tomography (CT), which has well recognized limitations, and increasingly functional imaging using integrated positron emission tomography and CT (PET/CT) is being used to provide more accurate staging, to guide biopsies, to assess response to therapy, and to identify recurrent disease. Staging and response to therapy will be discussed in this review.     

Whole-body 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for accurate staging of Hodgkin's disease

Background: Staging of Hodgkin's disease (HD) is accomplished by a variety of invasive and non-invasive modalities. This prospective study was undertaken to investigate the value of whole-body positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in defining regions involved by lymphoma compared with conventional staging methods in patients with HD.Patients and methods: Fourty-four newly diagnosed patients with HD underwent FDG-PET as part of their initial staging work-up. PET findings were correlated with findings of conventional staging including computed tomography, ultrasound, bone scanning, bone marrow biopsy, liver biopsy and laparotomy. When results of FDG-PET differed to those obtained by conventional methods reevaluation was performed by biopsy, if possible, or magnetic resonance imaging.Results: The results of FDG-PET were compared with three hundred twenty-one conventional staging procedures performed in 44 patients. FDG-PET was positive in 38 of 44 (86%) patients at sites of documented disease. PET detected additional lesions in five cases previously not identified by conventional staging methods. In another case a nodal lesion suspect on CT was negative at FDG-PET and was settled as true negative by biopsy. As a consequence of PET findings five patients had to be upstaged and one patient had to be downstaged, resulting in changes in treatment strategy in all six cases (14%). FDG-PET failed to visualize sites of HD in four patients. In two of our patients a false positive PET result was obtained.Conclusions: Our data indicate that FDG-PET provides an imaging technique that appears to visualize involved lesions in most patients with HD and is useful in the managment of these patients.     

Lymph node staging by means of positron emission tomography is less accurate in non-small cell lung cancer patients with enlarged lymph nodes: analysis of 1,145 lymph nodes

BACKGROUND: Despite documented superiority of integrated positron emission tomography-computerized tomography (PET-CT) over computerized tomography (CT) in lymph node staging in non-small cell lung cancer, little is known about the sensitivity, specificity and accuracy of integrated PET-CT among enlarged lymph nodes. We sought to assess if PET-CT is uniformly accurate among enlarged and non-enlarged lymph nodes. METHODS: A retrospective review of 206 consecutive patients with histologically proven non-small cell lung cancer who underwent resection and/or mediastinoscopy in our centre over 30 months period was carried out. All these patients had pre-operative staging with integrated PET-CT as an adjunct to chest CT prior to resection and/or mediastinoscopy. Diabetic patients (BM>or=8.0 mmol/l) and those who received neo-adjuvant chemotherapy were excluded. The pathological results of all these cases were reviewed and correlated with those on CT and integrated PET-CT. RESULTS: The sensitivity, specificity, accuracy, positive and negative predictive values were higher in integrated PET-CT than CT alone in all lymph nodes, whether N1 or N2. When lymph nodes were stratified by size, the sensitivity of PET-CT was significantly higher among enlarged (>1cm) than non-enlarged (1cm) should be with caution as the specificity of PET-CT is lower and its ability to detect truly negative nodes become reduced. NSCLC patients with enlarged nodes by CT criteria who are PET-CT negative may require cervical mediastinoscopy to rule out metastatic spread to these nodes. Prospective studies are warranted.     

The value of [18F]fluoro-2-deoxy-D-glucose positron emission tomography in the selection of patients with stage IIIA-N2 non-small cell lung cancer for combined modality treatment

Combined modality treatment (CMT) for patients with stage IIIA-N2 non-small cell lung cancer (NSCLC) is at present studied extensively. To select patients with truly stage IIIA-N2 disease, however, proves to be difficult with current diagnostic tests. Distant metastases may become clinically overt during induction chemotherapy (IC) or shortly after, revealing the inaccuracies of current staging algorithms. A prospective study with [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) in IIIA-N2 NSCLC patients was performed to assess its value in the selection of this patient group. Fifty-seven patients received a whole body FDG PET scan as part of an ongoing response monitoring trial. Results were compared with conventional staging. In 32/57 (56%) PET suggested upstaging, which was confirmed in 17/57 (30%) with a median follow-up of 16 (range 2-49) months. These results show that using the conventional staging algorithm a substantial group of patients was understaged. FDG PET improves the selection of patients suitable for CMT.     

非小细胞肺癌纵隔淋巴结分期诊断研究进展

目的 肺癌是全球死亡率最高的恶性肿瘤之一,其中80％是非小细胞肺癌(non-small cell lung cancer,NSCLC).本研究回顾总结国内外NSCLC纵隔淋巴结分期诊断的研究进展,为临床采取合适的检查方法及治疗方案提供一定指导.方法 应用PubMed、中国知网、万方数据库、维普中文期刊服务平台等检索系统,以“NSCLC、术前、纵隔淋巴结分期、电子发射计算机体层显像-X线计算机体层(integrated positron emission tomography-computed tomography,PET-CT)、计算机断层成像(computed tomography,CT)、磁共振成像(magnetic resonance imaging,MRI)、纵隔镜、针吸活检术”为关键词,检索2000-07-27-2016-03-05相关文献,纳入标准:(1) NSCLC纵隔淋巴结的有创性外科检查方法;(2) NSCLC纵膈淋巴结的无创性影像学检查方法.结果 根据纳入标准纳入分析40篇相关文献.总结出无创性影像学分期、有创性外科分期各检查的优缺点、灵敏度、特异度、准确度、假阳性率、假阴性率及临床应用情况.NSCLC纵隔淋巴结检查方法中,CT对纵隔淋巴结分期的灵敏度(61.1％)及特异性(71.1％)均较低;脱氧葡萄糖(fluorodeox-yglucose,FDG)PET-CT灵敏度和特异度分别是64％和83.3％,但其价格昂贵;磁共振扩散加权成像诊断NSCLC纵隔淋巴结转移的效能优于FDG PET-CT;纵隔镜灵敏度和特异度分别是78％和100％,存在一定的并发症(2％)和死亡率(0.08％);支气管内镜超声引导针吸活检操作方便,其灵敏度和特异度分别是92％和100％,不能取检主动脉旁及下纵隔淋巴结.结论 CT已作为评估NSCLC纵隔淋巴结分期的常规检查;FDG PET-CT是最准确的无创性检查方法;纵隔镜是目前诊断纵隔淋巴结分期的金标准,未来的趋势是各技术整合、优势互补以达到更准确的NSCLC纵隔分期.     

18F-deoxyglucose positron emission tomography (FDG-PET) for the planning of radiotherapy in lung cancer: high impact in patients with atelectasis.

PURPOSE: 18F-deoxyglucose positron emission tomography (FDG-PET) is increasingly applied in the staging of lung cancer (LC). This study analyzes the potential contribution of PET in radiotherapy planning for LC with special respect to tumor-associated atelectasis. METHODS AND MATERIALS: Thirty-four patients with histologically confirmed LC, who had been examined by PET during pretreatment staging, were included. All were irradiated after CT-based therapy planning with anterior/posterior (AP) portals encompassing the primary tumor and the mediastinum (CT portals, CP). The result of the PET examination was unknown in treatment planning. In retrospect, a PET portal (PP) was delineated and compared with the CP. RESULTS: In 12/34 cases, the shape and/or size of the portals were changed, primarily (n = 10) the size of the fields was reduced. The median area of CP was 182 cm2 versus 167 cm2 of PP. Seventeen of 34 patients had dys- or atelectasis caused by a central primary tumor. In these cases, differences between CP and PP were significantly more frequent than in the other patients (8/17 vs. 3/17, p = 0.03). CONCLUSION: In this retrospective analysis, the information provided by FDG-PET would have contributed to a substantial reduction of the size of radiotherapy portals. This applies particularly for patients with tumor-associated dys- or atelectasis.     

Radiotherapy treatment planning for patients with non-small cell lung cancer using positron emission tomography (PET).

PURPOSE: Many patients with non-small cell lung cancer (NSCLC) receive external beam radiation therapy as part of their treatment. Three-dimensional conformal radiation therapy (3DCRT) commonly uses computed tomography (CT) to accurately delineate the target lesion and normal tissues. Clinical studies, however, indicate that positron emission tomography (PET) has higher sensitivity than CT in detecting and staging of mediastinal metastases. Imaging with fluoro-2-deoxyglucose (FDG) PET in conjunction with CT, therefore, can improve the accuracy of lesion definition. In this pilot study, we investigated the potential benefits of incorporating PET data into the conventional treatment planning of NSCLC. Case-by-case, we prospectively analyzed planning target volume (PTV) and lung toxicity changes for a cohort of patients. MATERIALS AND METHODS: We have included 11 patients in this study. They were immobilized in the treatment position and CT simulation was performed. Following CT simulation, PET scanning was performed in the treatment position using the same body cast that was produced for CT simulation and treatment. The PTV, along with the gross target volume (GTV) and normal organs, was first delineated using the CT data set. The CT and PET transmission images were then registered in the treatment planning system using either manual or automated methods, leading to consequent registration of the CT and emission images. The PTV was then modified using the registered PET emission images. The modified PTV is seen simultaneously on both CT and PET images, allowing the physician to define the PTV utilizing the information from both data sets. Dose-volume histograms (DVHs) for lesion and normal organs were generated using both CT-based and PET+CT-based treatment plans. RESULTS: For all patients, there was a change in PTV outline based on CT images versus CT/PET fused images. In seven out of 11 cases, we found an increase in PTV volume (average increase of 19%) to incorporate distant nodal disease. Among these patients, the highest normal-tissue complication probability (NTCP) for lung was 22% with combined PET/CT plan and 21% with CT-only plan. In other four patients PTV was decreased an average of 18%. The reduction of PTV in two of these patients was due to excluding atelectasis and trimming the target volume to avoid delivering higher radiation doses to nearby spinal cord or heart. CONCLUSIONS: The incorporation of PET data improves definition of the primary lesion by including positive lymph nodes into the PTV. Thus, the PET data reduces the likelihood of geographic misses and hopefully improves the chance of achieving local control.     

Whole body 18F-2-deoxyglucose positron emission tomography to restage non-small cell lung cancer

The helpfulness of 18F-2-deoxyglucose positron emission tomography (FDG-PET) in restaging non-small cell lung cancer (NSCLC) has not been extensively evaluated. A total of 156 patients referred for restaging of NSCLC were retrospectively evaluated. According to the classification of American Joint Committee on Cancer, stages I and II were defined as conventionally resectable, stage IIIA as locally advanced but resectable, stage IIIB as locally advanced but unresectable, and stage IV as absolutely unresectable. Compared to initial staging by chest computed tomographic findings, FDG-PET down-staged 45/156 (29%) and up-staged 52/156 (33%) NSCLCs. In addition, 37/156 (23%) patients were reclassified from resectable to unresectable and 22/156 (14%) patients were reclassified from unresectable to resectable. Our results prove the helpfulness of whole body FDG-PET for restaging NSCLC.     

~(18)F-FDG PET对非小细胞肺癌预后预测价值的研究进展

目的:探讨18F-FDG PET对非小细胞肺癌预后的研究进展,指导临床中PET的应用。方法:应用计算机在PUBMED数据库检索2002~2007年有关18F-FDG PET对非小细胞肺癌预后的文章,并限定文献语种为英文,检索词fluorodeoxyglucose(FDG)、positron emmition tomography(PET)和non-small cell lung cancer和prognosis。同时,计算机检索中国期刊全文数据库2002~2007年的相关文章,检索词为PET和肺肿瘤,限定文章语言种类为中文。对选择的资料进行初审,选取和PDG-PET以及与其非小细胞肺癌预后相关的文献,然后查找全文。排除标准:1)重复研究;2)个案报道。共收集到相关文献59篇,排除重复或类似的同一研究,最终纳入30篇符合标准的文献。结果:大部分研究证明,肺癌原发灶的18F-氟脱氧葡萄糖(18F-FDG)标准摄取值(standardized uptake value,SUV)与患者的预后相关,治疗前后SUV值高的患者预后相对SUV值低的患者对放化疗敏感性差;进一步的研究显示,其复发的概率相对高,预后较差。但是放疗...     

Mediastinal lymph node staging by means of positron emission tomography is less sensitive in elderly patients with non-small-cell lung cancer

PURPOSE: We sought to identify the impact of age on the sensitivity and specificity of integrated positron emission tomography/computed tomography (PET-CT; CT) on mediastinal lymph node staging of patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: We conducted a retrospective review of 206 consecutive patients with histologically proven NSCLC who underwent resection and/or mediastinoscopy in our center between September 2004 and January 2007. All of these patients had preoperative staging with integrated PET-CT as an adjunct to chest CT before resection and/or mediastinoscopy. Diabetic patients and patients who received neoadjuvant chemotherapy were excluded. The pathologic results of all of these cases were reviewed and correlated with those on CT and integrated PET-CT. RESULTS: The sensitivity and positive predictive values (PPV) of PET-CT in mediastinal nodal staging were significantly lower in elderly patients (age>or=65 years; sensitivity, 42%; PPV, 66%) than in younger patients (age<65 years; sensitivity, 52%; PPV, 74%). Specificity and negative predictive values were similar in both groups. CONCLUSION: PET-CT staging of the mediastinum is less sensitive in elderly patients with NSCLC who have a lower PPV. Positive mediastinal uptake on PET-CT should be verified by mediastinoscopy, irrespective of age. Elderly patients with positive mediastinal uptake should not be refuted a curative intent surgical resection on the basis of positive mediastinal uptake alone.     

Delayed (18)F-fluoro-2-deoxy-D-glucose positron emission tomography scan for differentiation between malignant and benign lesions in the pancreas

BACKGROUND: Positron emission tomography (PET) using (18)F-fluoro-2-deoxy-D-glucose (FDG) has been used for the evaluation of various tumors, but accumulation in inflammatory lesions makes it a controversial modality. The aim of this study was to investigate the usefulness of delayed scanning in differentiation between malignant and benign lesions in the pancreas. METHODS: Forty-seven patients with suspected pancreatic carcinoma were studied by FDG-PET. All patients received approximately 370 megabequerels of FDG after a transmission scan, and an emission scan was performed 1 hour and 2 hours later for all patients. A subset of 19 patients was also scanned at 3 hours postinjection. The standardized uptake value (SUV) was determined, and the retention index was calculated by dividing the increase in the SUV between 1 hour and 2 hours postinjection by the SUV at 1 hour postinjection. RESULTS: Of 27 malignant lesions, the SUVs of 22 lesions increased at 2 hours postinjection, whereas the FDG uptake in 17 of 20 benign lesions decreased. The SUVs at 3 hours postinjection were higher than those at 2 hours postinjection in 9 of 14 malignant lesions and in 2 of 5 benign lesions. Malignant lesions showed a higher retention index than benign lesions (mean +/- standard deviation: 12. 36 +/- 13.37 and -7.05 +/- 17.28, respectively; P < 0.0001). Applying an SUV of 2.5 at 1 hour postinjection with the cut-off value for the differentiation between malignant and benign lesions caused one false negative result and seven false positive results, with a diagnostic accuracy of 83.0% (39 of 47 patients). However, combining the retention index with the SUV obtained at 2 hours postinjection provided a higher diagnostic accuracy (91.5%; 43 or 47 patients) than the SUV alone. The false negative rate remained constant when the retention index was taken into account. Images at 3 hours postinjection usually were unhelpful in differentiating further between malignant lesions and benign lesions. CONCLUSIONS: The current data suggest that delayed FDG-PET scanning at 2 hours postinjection may contribute to differentiation between malignant and benign lesions in the pancreas.     

手术前PET-CT对非小细胞肺癌纵隔淋巴结转移的诊断价值

目的探讨术前PET-CT显像对非小细胞肺癌(NSCLC)纵隔淋巴结转移的诊断价值。方法选取2011年10月至2012年8月间进行手术根治或纵隔淋巴结活检的25例NSCLC患者。所有患者术前均行PET-CT检查,并根据手术或纵隔镜结果进行诊断及分期,计算PET-CT对诊断纵隔淋巴结的准确性、灵敏度、特异度、阳性预测值和阴性预测值。结果 25例患者中,纵隔淋巴结阳性率为28.0%。PET-CT对诊断纵隔淋巴结转移的准确性、灵敏度、特异度、阳性和阴性预测值分别为76.0%、57.1%、83.3%、57.1%和83.3%。3例假阴性患者的纵隔最大淋巴结短径分别为1.0、0.9和0.7cm。3例假阳性患者均为炎性增生。结论 PET-CT对NSCLC手术患者纵隔淋巴结转移的诊断灵敏度较低,特异度和阴性预测值较高。因此,PET-CT显示为阳性的纵隔淋巴结,有必要行纵隔镜检查;而阴性者则可不需行纵隔镜检查。     

18F-FDG PET对非小细胞肺癌预后预测价值的研究进展

目的:探讨18F-FDG PET对非小细胞肺癌预后的研究进展,指导临床中PET的应用.方法:应用计算机在PUBMED数据库检索2002～2007年有关18F-FDG PET对非小细胞肺癌预后的文章,并限定文献语种为英文,检索词fluorodeoxyglucose (FDG)、positron emmition tomography (PET)和non-small cell lung cancer和prognosis.同时,计算机检索中国期刊全文数据库2002～2007年的相关文章,检索词为PET和肺肿瘤,限定文章语言种类为中文.对选择的资料进行初审,选取和PDGPET以及与其非小细胞肺癌预后相关的文献,然后查找全文.排除标准:1)重复研究;2)个案报道.共收集到相关文献59篇,排除重复或类似的同一研究,最终纳入30篇符合标准的文献.结果:大部分研究证明,肺癌原发灶的18F-氟脱氧葡萄糖(18F-FDG)标准摄取值(standardized uptake value, SUV)与患者的预后相关,治疗前后SUV值高的患者预后相对SUV值低的患者对放化疗敏感性差;进一步的研究显示,其复发的概率相对高,预后较差.但是放疗前后SUV变化能否作为独立的预后因素尚存在争议.结论:PET在非小细胞肺癌的预后判断方面有重要意义.不仅可以广泛用于放化疗疗效评价,也可用于预测肺癌治疗后复发以及对患者生存期的预测.     

The role of 18F-fluoro-deoxy-glucose positron emission tomography (FDG-PET) in the management of patients with colorectal cancer.

AIM: In patients with colorectal cancer an accurate diagnostic work-up is mandatory in order to perform the most specific treatment. At this moment 18F-fluoro-deoxy-glucose positron emission tomography (FDG-PET) is considered an accurate imaging technique in staging/restaging several malignancies. The aim of this paper is to review the scientific literature available about the role of FDG-PET in the management of patients with colorectal cancer. METHODS: An overview on Medline of scientific literature concerning FDG-PET and colorectal cancer was performed. The most relevant studies are reported. Advantages, limitations and new chances in using FDG-PET in these subsets of patients are summarized. RESULTS: FDG-PET is a useful tool in the evaluation of colorectal cancer. In comparison to conventional imaging technique, FDG-PET has an additional diagnostic value because it allows to metabolically characterize undetermined lesions suspected for recurrence of disease, to perform a complete pre-surgical staging and to identify occult metastatic disease. In clinical practice its use leads to a change in therapeutic choices in a high percentage of cases. CONCLUSIONS: FDG-PET should be considered an essential diagnostic tool in the management of patients with colorectal cancer, especially in recurrent disease evaluation.     

18F-fluoro-2-deoxy-D-glucose positron emission tomographic imaging: recent developments in head and neck cancer

PURPOSE OF REVIEW: Positron emission tomography using 18F-fluoro-2-deoxy-D-glucose (18FDG-PET) is well established in clinical routine as a metabolism-based whole-body imaging tool for cancer diagnosis and follow-up. Several reports have appeared indicating the potential and limitations of this technique in head and neck cancer (HNC). This review limits its scope to the recent advances using 18FDG-PET in the clinical management of HNC. RECENT FINDINGS: The combination of 18FDG-PET and sentinel node biopsy has been explored for the surgical treatment planning of oral and oropharyngeal cancer. Recent reports indicate that multimodality imaging combining PET with high-end CT scanning increases the diagnostic accuracy. 18FDG-PET has a potential for use in radiation treatment planning and for the prediction of response and early evaluation of treatment efficacy. SUMMARY: Increasingly 18FDG-PET is used as a clinical imaging modality in the different stages of the management of HNC. In particular, its clinical value in initial staging of neck lymph nodes and in the evaluation of recurrent or residual disease is well established. In these settings 18FDG-PET has been shown to be more accurate than conventional imaging. Recent studies indicate that 18FDG-PET could be of additional value in staging the N0 neck, in radiation treatment planning, and in prediction of treatment efficacy.     

FDG PET对非小细胞肺癌合并肺不张三维适形放疗时靶区确定的临床意义

目的 探讨^18F-脱氧葡萄糖（FDG）PET对合并肺不张的非小细胞肺癌（NSCLC）行三维适形放疗时病变靶区确定的临床意义。方法 对14例经病理组织学证实为NSCLC且其影像学检查伴有不同程度肺不张者，先后行胸部增强明扫描及胸部或全身FDGP盯肿瘤显像。根据扫描及显像结果勾画原发病灶范围，分别称为CT-GTV和PET-GTV，并由CMS治疗计划系统给出GTV体积的具体数值加以比较。结果 全部患者的CT-GTV与PET-GTV均有不同程度差别，其中1例患者PET-GTV较CT-GTV增加16．9％（22cm^3），CT-GTV为130cm3，PET-G11V为152cm^3；13例患者PET-GTV较CT-GTV平均减少20．4％（27．2cm^3），CT-GTV平均为133cm^3（90-180cm^3），PET-GTV平均为106cm^3（60—153cm^3）（P=0．000）。GTV的减少主要原因是PET显像除外了因肿瘤原因造成的肺不张，从而引起靶区范围的缩小，进而避免对周围正常组织（主要是正常或不张的肺组织、脊髓及心血管）的不必要照射，最大限度地保护了正常组织。结论 FDG PET在确定肺不张与局部病变相互关系方面具有一定临床价值，并由此提高了靶区定位的精确性。     

Value of positron emission tomography for lung cancer staging.

OBJECTIVE: The therapeutic strategy in non-small-cell lung cancer (NSCLC) requires exact staging of tumour invasion (T) as well as differentiation between ipsi- and contralateral lymph node invasion (N1/2 vs N3). [18F]FDG-positron emission tomography (FDG-PET) has been shown to detect invaded N with high accuracy while correct determination of T appears to be unclear. The purpose of this prospective study was to evaluate benefit and necessity of 18FDG-PET as an additive to conventional staging modalities. METHODS: Forty patients with suspected non-small-cell lung cancer (NSCLC) were staged by means of computed tomography (CT), bronchoscopy, mediastinoscopy and bone scintigraphy. Additionally, attenuation corrected FDG-PET of the thorax was performed pre-operatively for analysis of T and N topography. After surgical resection with radical lymphadenectomy T and N staging results of CT and PET were compared with the pathological diagnoses. Specificity, sensitivity, positive predictive value and accuracy of CT and PET were calculated. RESULTS: Twenty three squamous cell carcinomas, 14 adenocarcinomas, and three non-malignant tumours were found. Accuracy of CT-T was 0.75 and of PET-T 0.78; accuracy of CT-N was 0.78 and of PET-N 0.80. By combination of CT-T and PET-T accuracy was 0.88. Combination of CT-N and PET-N yielded an accuracy of 0.90. In two out of three cases, PET correctly determined T0. In two cases non-malignant inflammatory lymph nodes were falsely staged as malignant by PET. CONCLUSIONS: Adequate pre-operative T- and N-staging is possible with both CT and FDG-PET. Accuracy can be improved by combination of CT and FDG-PET. FDG-PET is superior to CT in order to differentiate between malignant and benign tumours. However, acute inflammation can mimic malignant lymph node invasion. FDG-PET is justified as a supporting staging measure in cases presenting unclear differentiation between N2 and N3 after conventional staging and is helpful in cases with unclear cell type of the primary tumour.     

18F-fluoro-2-deoxy-glucose uptake predicts clinical outcome in patients with gefitinib-treated non-small cell lung cancer.

PURPOSE: To evaluate response and survival according to (18)F-fluoro-2-deoxy-glucose uptake at presentation in patients with gefitinib-treated non-small cell lung cancer. EXPERIMENTAL DESIGN: We retrospectively analyzed 84 positron emission tomography/computed tomography findings. Patient characteristics, response rates, and survivals were evaluated according to the maximum standardized uptake value (SUV) of primary tumor. The cutoff value of SUVs was obtained from receiver operating characteristic analysis. RESULTS: The response rate (RR) was higher for never-smokers (41%) than ever-smokers (9%; P=0.001). Patients with adenocarcinoma showed higher RR than those with other tumor histopathology (35% versus 9%; P=0.009). The SUV was significantly lower in patients who were never-smokers (P=0.005), patients with adenocarcinoma (P<0.001), and female patients (P=0.017). Patients with a low SUV showed higher RR compared with those with a high SUV (53% versus 18%; P=0.003). Prolonged progression-free survival was observed in patients with low SUVs compared with those with high SUVs (median, 33.1 weeks versus 8.6 weeks; P=0.003). While controlling for performance status, smoking history, and pathology, the high SUV conferred unfavorable outcome (hazard ratio, 2.3; P=0.012). In terms of overall survival, a low SUV was associated with favorable outcome in univariate analysis (P=0.011). Patients with a low SUV showed prolonged survival in multivariate analysis (P=0.043). CONCLUSIONS: These results suggest that low SUVs at presentation can predict favorable response and survival in gefitinib-treated non-small cell lung cancer patients.