Selective mediastinal node irradiation based on FDG-PET scan data in patients with non-small-cell lung cancer: a prospective clinical study

PURPOSE: To evaluate the patterns of recurrence when selective mediastinal node irradiation based on FDG-PET scan data is used in patients with non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: A prospective Phase I/II study was undertaken on 44 patients with NSCLC without detectable distant metastases on CT and FDG-PET scan, delivering either 61.2 Gy in 34 fractions over 23 days or 64.8 Gy in 36 fractions over 24 days (1.8 Gy b.i.d. with 8-h interval). Only the primary tumor and the positive mediastinal areas on the pretreatment FDG-PET scan were irradiated. Isolated nodal failure was defined as recurrence in the regional nodes outside of the clinical target volume, in the absence of in-field failure. RESULTS: The CT and FDG-PET stage distribution was as follows: Stage I: 8 patients (18%) and 13 patients (29%); Stage II: 6 patients (14%) and 10 patients (23%); Stage IIIA: 15 patients (34%) and 7 patients (16%); Stage IIIB: 15 patients (34%) and 14 patients (32%), respectively. After a median follow-up time of 16 months (95% confidence interval [CI], 11-21 months) postradiotherapy, 11 patients (25%) developed a local recurrence. Only 1 patient (crude rate, 2.3%; upper bound of 95% CI, 10.3%), with a Stage II tumor on both CT and PET, developed an isolated nodal failure. The median actuarial overall survival was 21 months (95% CI, 14-28 months), and the median actuarial progression-free survival was 18 months (95% CI, 12-24 months). CONCLUSIONS: Selective mediastinal node irradiation based on FDG-PET scan data in patients with NSCLC results in low isolated nodal failure rates. In the Phase I component of this trial, radiation dose escalation up to 64.8 Gy in 36 fractions over 24 days is feasible.     

A case of gastric gastrointestinal stromal tumor operated after low-dose chemotherapy with imatinib mesylate

A 76-year-old man was admitted to our hospital because of tarry motions. Endoscopic findings showed an ulcer on a large submucosal tumor in the stomach. Abodminal CT scan showed a protruding lesion of approximately 13 cm at the lumen of the gastric body. FDG-PET imaging revealed FDG uptake in the gastric body and abdominal cavity. We diagnosed it as GIST with peritoneal dissemination clinically, and treatment with 300 mg of imatinib mesylate was started in December 2006. The main tumor was reduced(reduction rate of 27%)and FDG-PET imaging revealed a decrease in FDG uptake in the main tumor and all disseminated tumors after 5 months of treatment. However, the drug was discontinued for arthritis(grade 3). Partial gastrectomy with sampling peritoneal nodules was performed in June 2007. The present case suggests that low-dose chemotherapy with imatinib mesylate may be useful as a preoperative therapy for a minimal surgery.     

Contralateral Cervicomediastinal Lymph Node Metastases from Clinically Occult Adenocarcinoma of the Lung

A 69-year-old woman with a right cervical lymphadenopathy presented with an adenocarcinoma on excisional biopsy. Computed tomography (CT) scans and a positron emission tomography scan demonstrated that the tumor was localized in the right paratracheal and cervical region. A clinical diagnosis of lung cancer arising from an unknown primary site was made based on the radiologic and immunohistochemical findings. Serial CT scans showed a growing nodule in the left apex from pinpoint size to 1 cm in diameter after several months, which was defined as the primary site at autopsy. The finding of a clinically occult lung cancer directly spreading to the contralateral mediastinal and cervical nodes by skipping ipsilateral hilar and mediastinal nodes is rare.     

Positron Emission Tomography with 18-Fluorodeoxyglucose in the Staging and Follow-up of Lymphoma in the Chest

The purpose of this retrospective study was to evaluate the accuracy of positron emission tomography (PET) using 18-F-fluorodeoxyglucose (FDG) in predicting lymphomatous involvement in the hilar and mediastinal regions in the staging and follow-up of patients with malignant lymphoma. One hundred forty-seven thoracic PET studies in 89 consecutive lymphoma patients were reviewed. Static FDG-PET imaging was performed following application of 270 MBq FDG (mean). Results of FDG-PET were compared with the findings of computed tomography (CT) in all patients and clinical follow-up examination. Eighty-nine of 147 (60%) PET studies showed no FDG uptake in the hilar or mediastinal regions, while 58 (40%) studies did detect FDG uptake in these regions. In 52 of 58 abnormal studies (90%), lymphomatous involvement of the hilar and/or mediastinal regions seen by CT was present. In the remaining six abnormal PET studies (10%), FDG uptake was considered as false-positive because of missing lesions on corresponding CT scans. In four patients false-positive FDG uptake was observed before treatment, in two patients after completion of therapy. In these two patients FDG uptake after therapy was caused by thymus hyperplasia. The remaining four cases before treatment remained unresolved. Sensitivity of FDG-PET was 96%, specificity 94%, positive predictive value 90%, and negative predictive value 98%, respectively. The present study suggests that FDG-PET has potential value in predicting lymphomatous involvement in the hilar and mediastinal regions. FDG-PET may obviate invasive diagnostic procedures in patients with lymphoma.     

A case of long-term survival after resection for postoperative solitary adrenal metastasis from esophageal adenocarcinoma

A 71-year-old man presented with chief complains of hoarseness and dysphagia. He was diagnosed to have an advanced esophageal adenocarcinoma in the middle thoracic esophagus for which chemoradiation therapy was started. Partial response was observed and he was referred to our hospital thereafter. After detailed examination, he underwent a subtotal esophagectomy followed by two-field lymphadenectomy in May 2001. Histopathological examination revealed a complete response. Ten months later, hematological examination showed a high serum CEA level and CT scan disclosed mediastinal lymph node recurrences. He received a course of systemic chemotherapy so called FP therapy and five months later, a course of combination chemotherapy with 700 mg/m2 5-FU on days 1-5 and 70 mg/m2 nedaplatin on day 1 was administered. Because the high serum CEA level sustained afterward, FDG-PET was undertaken in March 2003. The right adrenal gland showed an intense abnormal FDG uptake and CT scan detected a low density mass in the area. Since no metastases could be identified in other sites, right adrenalectomy was performed. Pathological finding was poorly-differentiated tubular adenocarcinoma. Five years and eleven months after adrenalectomy, he died of pneumonia with no signs of recurrence. Surgical resection may contribute to improving the prognosis of solitary adrenal metastasis of esophageal cancer without the other noncurative factors.     

18FDG-PET/CT对评价TACE联合RFA治疗原发性肝癌的效果的价值

背景与目的:原发性肝癌经动脉导管栓塞化疗(transcatheterarterialchemo-embolization,TACE)联合射频消融(radiofrequencyablation,RFA)治疗后,CT扫描对判断是否有肿瘤残留存在一定的困难,而18FDG-PET/CT(18-fluorodeoxyglucose-positronemissiontomograply/CT)在判断肿瘤残留上具有优势。本研究对13例原发性肝癌经TACE联合RFA治疗周后,采用CT和18FDG-PET/CT检查是否存在肿瘤残留,分析CT和18FDG-PET/CT在判断肿瘤残留上的差异,并根据18FDG-PET/CT的结果指导肿瘤治疗。方法:本组13例原发性肝癌患者共有18个病变,肿瘤最长直径为0.8～16.0cm。12例为初治病例;1例为肝癌手术后复发,肝内共发现有3个病变。经过TACE联合RFA治疗后2～3周,对比CT和18FDG-PET/CT检查的结果;如发现有肿瘤残留,在2～3周内对其进一步行RFA治疗。结果:13例患者经一次TACE联合一次RFA治疗2～3周,经病变区域活检及数字减影血管造影等检查发现11例有部分肿瘤残留,肿瘤残留最长直径为1.0～2.1cm;CT增强扫描检查检出5例,18FDG-PET/CT检出有10例残留,CT与18FDG-PET/CT检出率分别为45.4%及90.9%。根据检查结果,在2～3周内经过第二次RFA治疗后,18FDG-PET/CT检查发现10例患者肿瘤无残留,另1例6周后复查18FDG-PET/CT发现肝内病变未控,患者带瘤生存。结论:原发性肝癌经TACE联合RFA治疗以及手术后,18FDG-PET/CT对判断肿瘤残留以及根据检查结果指导RFA治疗较CT检查具有更大的优势。     

Usefulness of (18)F-FDG positron emission tomography/computed tomography for the diagnosis of pyothorax-associated lymphoma: A report of three cases

Pyothorax-associated lymphoma (PAL) is a unique and rare non-Hodgkin's lymphoma developing in the pleural cavity following a long-standing history of chronic pyothorax (CP). The development of F-18 2'-deoxy-2fluoro-D-glucose (FDG) positron emission tomography combined with computed tomography (PET/CT) has contributed to the evaluation of lymphoma staging. However, only a few studies describing FDG-PET/CT findings in PAL have been published. This study reported three cases of PAL; all 3 patients had previously undergone artificial collapse therapy for pulmonary tuberculosis. Both the first case (an 84-year-old male) and second case (an 83-year-old male) complained of abdominal pain. An ultrasound scan revealed a mass shadow in the left chest wall without abnormal findings in the abdomen, and the CT and magnetic resonance imaging scans suggested malignant lymphoma of the left chest. FDG-PET/CT imaging showed extremely intense FDG uptake only in the left pleura and chest wall. Diagnosis was CP in the two patients, showing a high maximum standardized uptake value (SUVmax: early, 14.8 and delayed, 19.4 in the first case; early, 20.8 and delayed, 27.3 in the second case, respectively). Histopathological analysis of the specimens obtained by biopsy of the PET/CT-positive pleural mass showed non-Hodgkin's, diffuse large B cell lymphoma in the two cases. The third case was a 79-year-old male with relapse after right pleuropneumonectomy for PAL (diffuse large B cell lymphoma) 4 years earlier. PET/CT showed intense FDG uptake (SUVmax: early, 19.9 and delayed, 35.7) in the right pleura and chest wall. Diagnosis was CP, suggesting the recurrence of PAL. Furthermore, abnormal intense FDG uptake was noted in the hilar, mediastinal and supraclavicular lymph nodes, as well as in the spleen. In conclusion, FDG-PET/CT imaging is useful in the evaluation of the area of invasion in PAL.     

False-Positive Mediastinal Lymphadenopathy on 18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography after Rectal Cancer Resection: A Case Report of Thoracoscopic Surgery in the Prone Position

(18)F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (integrated FDG PET/CT) has been used to diagnose recurrence and differentiate postoperative changes from lymph node metastasis in colorectal cancer, although its accuracy is questionable. We report a prone thoracoscopic surgery for a rectal cancer patient in which false-positive mediastinal lymph nodes were found on FDG-PET/CT. A 60-year-old man underwent a laparoscopic high anterior resection and D3 lymph node dissection for rectal cancer. The histopathological diagnosis was moderately differentiated adenocarcinoma of the rectum, stage IIIB (pT3N1M0), necessitating oral fluoropyrimidine agent S-1. After the primary surgery, a solitary mediastinal lymph node measuring 30 mm in diameter was detected, and abnormal accumulation was confirmed by FDG-PET/CT (SUV(max), 11.7). Thoracoscopic resection was performed in the prone position, but histopathological results showed no metastasis. He was subsequently diagnosed with reactive lymphadenitis. The patient was discharged on postoperative day 4 in good condition and is alive without recurrence 12 months after surgery. PET/CT is useful for the detection of colorectal cancer recurrence; however, it does have a high false-positive rate for mediastinal lymph nodes. There is a limit to its diagnostic accuracy, and one must determine the indication for surgical treatment carefully. Surgery in the prone position is a useful and minimally invasive approach to the mediastinum and allows aggressive resection to be performed.     

FDG-PET evaluation of vaginal carcinoma

PURPOSE: To compare the results of CT and positron emission tomography (PET) and F-18 fluorodeoxyglucose (FDG) in the detection of the primary tumor and lymph node metastases in carcinoma of the vagina. METHODS AND MATERIALS: This was a prospective registry study of 23 consecutive patients with carcinoma of the vagina, in which we respectively compared the results of CT and whole-body FDG-PET. The tumor was clinical Stage II in 16 patients, Stage III in 6, and Stage IVa in 1 patient. The primary tumor ranged in size from 2 to 10 cm (mean 4.9), and 4 patients had palpable groin lymph nodes. All patients were treated with external beam radiotherapy and brachytherapy, 14 received concurrent chemotherapy, and 2 underwent primary tumor excision before the imaging evaluation. The median follow-up was 21 months in those patients alive without disease. Survival was estimated by the Kaplan-Meier method. RESULTS: Of the 21 patients with an intact primary tumor, CT visualized it in 9 (43%). CT also demonstrated abnormally enlarged groin lymph nodes in 3 patients and both groin and pelvic lymph nodes in 1 patient (4 of 23, 17%). FDG-PET identified abnormal uptake in all 21 intact primary tumors (100%). Abnormal uptake was found in the groin lymph nodes in 4 patients, pelvic lymph nodes in 2, and both groin and pelvic lymph nodes in 2 patients (8 of 23, 35%). The 3-year progression-free and overall survival estimate was 73% and 68%, respectively. CONCLUSION: The results of this study have demonstrated that FDG-PET detects the primary tumor and abnormal lymph nodes more often than does CT.     

A case of endobronchial squamous cell lung cancer successfully treated with weekly chemotherapy of carboplatin and paclitaxel

A 69-year-old man had undergone low anterior resection and a right lobe resection of the liver for rectum cancer and metastatic liver tumor at the age of 66 years. He presented at our hospital because of an abnormal shadow on a CT chest scan, which indicated a tumor shadow 2.5 cm in size in the lingular lobe and enlarged hilar and mediastinal lymph nodes. A bronchoscopic tumor biopsy revealed pulmonary metastasis from the rectum cancer. Bronchoscopic examination also identified an endobronchial squamous cell lung cancer, which almost completely obstructed the orifice of B1 and B2. We concluded that the patient had squamous cell lung cancer with metastases in the mediastinal lymph nodes. He was initially treated with weekly chemotherapy with carboplatin (AUC 1.25) and paclitaxel (70 mg/m2). The endobronchial tumor was markedly reduced in size after 2 weeks of the chemotherapy. Furthermore, after 6 weeks of the chemotherapy, the tumor had disappeared completely, and 11 days later, lower division segmentectomy and hilar and mediastinal lymph node dissection were performed. Pathological examination revealed no metastases in the lymph nodes. The patient has continued to receive chemotherapy as an outpatient and has been well without recurrence of any metastases for over 16 months.     

Tumor response and survival predicted by post-therapy FDG-PET/CT in anal cancer

PURPOSE: To evaluate the response to therapy for anal carcinoma using post-therapy imaging with positron emission tomography (PET)/computed tomography and F-18 fluorodeoxyglucose (FDG) and to compare the metabolic response with patient outcome. PATIENTS AND METHODS: This was a prospective cohort study of 53 consecutive patients with anal cancer. All patients underwent pre- and post-treatment whole-body FDG-PET/computed tomography. Patients had been treated with external beam radiotherapy and concurrent chemotherapy. Whole-body FDG-PET was performed 0.9-5.4 months (mean, 2.1) after therapy completion. RESULTS: The post-therapy PET scan did not show any abnormal FDG uptake (complete metabolic response) in 44 patients. Persistent abnormal FDG uptake (partial metabolic response) was found in the anal tumor in 9 patients. The 2-year cause-specific survival rate was 94% for patients with a complete vs. 39% for patients with a partial metabolic response in the anal tumor (p = 0.0008). The 2-year progression-free survival rate was 95% for patients with a complete vs. 22% for patients with a partial metabolic response in the anal tumor (p < 0.0001). A Cox proportional hazards model of survival outcome indicated that a complete metabolic response was the most significant predictor of progression-free survival in our patient population (p = 0.0003). CONCLUSIONS: A partial metabolic response in the anal tumor as determined by post-therapy FDG-PET is predictive of significantly decreased progression-free and cause-specific survival after chemoradiotherapy for anal cancer.     

A clinicopathological study of resected non-small cell lung cancers 2 cm or less in diameter: a prognostic assessment

The detection and diagnosis of small-sized (2 cm or less) non-small cell lung cancer (NSCLC) has increased with the development of computed tomography (CT). Over 80% of 5-year survival rate has been reported in surgically treated peripheral lung cancer. There are systematic mediastinal and hilar lymph node involvement pleural invasion and intrapulmonary metastasis even with tumor diameter less than 2 cm. The appropriate surgical procedure for such kinds of lung cancer is lobectomy with mediastinal lymph node dissection. To evaluate the prognostic factors and establish the optimal surgical strategy, we analyzed the clinicopathologic features and survival benefit in different tumor size of peripheral small-sized NSCLC. Among the resected lung cancer cases between January 1999 and July 2001, 185 patients were retrospectively analyzed in surgical methods, lymph node involvement, CT scan findings and survival rates. Survival was analyzed by Kaplan–Meier method and log-rank test. Lymph node involvement was recognized in 26(14.05%) patients. There was no statistically significant difference in the incidence of lymph node involvement between tumors 1.6–2.0 cm (17.82%) in diameter than in those 1.0–1.5 cm (11.94%). There was no lymph node metastasis in tumors less than 1.0 cm in diameter. The 5-year survival rates with or without lymph node involvement were 89.98 and 46.15%, respectively, showing significant difference (P = 0.000). The overall 5-year survival rate was 83.78%. The 5-year survival rate in tumors 1.6–2.0 cm, 1.0–1.5 cm and less than 1.0 cm in diameter was 80.20, 85.07 and 100%, respectively, and showing significant difference(P = 0.035). The 5-year survival rate of 19 patients showing ground-glass opacity (GGO) on CT scan was 94.74% without any metastasis and recurrence after operation. There are systematic mediastinal and hilar lymph node involvement even with tumor diameter less than 2 cm. The results of the present study suggested that systematic lymph node dissection is necessary even for cases with tumor diameter less than 2 cm. However, if the tumor is within 1.0 cm in diameter with obvious GGO showing on chest CT scan, these are good candidates for partial resection without mediastinal lymph node dissection.     

FDG-PET/CT in the evaluation of anal carcinoma

PURPOSE: Surgical staging and treatment of anal carcinoma has been replaced by noninvasive staging studies and combined modality therapy. In this study, we compare computed tomography (CT) and physical examination to [(18)F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in the staging of carcinoma of the anal canal, with special emphasis on determination of spread to inguinal lymph nodes. METHODS AND MATERIALS: Between July 2003 and July 2005, 41 consecutive patients with biopsy-proved anal carcinoma underwent a complete staging evaluation including physical examination, CT, and 2-FDG-PET/CT. Patients ranged in age from 30 to 89 years. Nine men were HIV-positive. Treatment was with standard Nigro regimen. RESULTS: [(18)F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) detected 91% of nonexcised primary tumors, whereas CT visualized 59%. FDG-PET/CT detected abnormal uptake in pelvic nodes of 5 patients with normal pelvic CT scans. FDG-PET/CT detected abnormal nodes in 20% of groins that were normal by CT, and in 23% without abnormality on physical examination. Furthermore, 17% of groins negative by both CT and physical examination showed abnormal uptake on FDG-PET/CT. HIV-positive patients had an increased frequency of PET-positive lymph nodes. CONCLUSION: [(18)F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography detects the primary tumor more often than CT. FDG-PET/CT detects substantially more abnormal inguinal lymph nodes than are identified by standard clinical staging with CT and physical examination.     

Occult mediastinal lymph node metastasis in NSCLC patients diagnosed as clinical N0-1 by preoperative integrated FDG-PET/CT and CT: Risk factors, pattern, and histopathological study

Background

Integrated F18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is widely used for mediastinal lymph node (MLN) staging in patients with non-small cell lung cancer (NSCLC). However, FDG-PET/CT has certain limitations. Prediction of occult MLN metastasis could allow selection of candidates for preoperative cervical mediastinoscopy or endobronchial ultrasound-guided transbronchial needle aspiration. This study defined risk factors for occult MLN metastasis in patients with NSCLC patients who were diagnosed as clinical N0-1 by preoperative integrated FDG-PET/CT and CT.

Methods

Consecutive patients with NSCLC who underwent staging using integrated FDG-PET/CT as an adjunct to CT prior to lung resection from October 2006 to September 2009 were evaluated retrospectively. The prevalence of MLN metastasis in patients diagnosed as clinical N0-1 was analyzed according to clinicopathological factors such as tumor location, tumor size, histology, and FDG uptake by the primary tumor. Risk factors for occult MLN metastasis were defined by multivariate analysis. Patterns of occult MLN metastasis were also analyzed and the involved MLNs were further examined histopathologically.

Results

The incidence of MLN metastasis was 11% (24 patients of 224). Multivariate analysis identified adenocarcinoma (P = 0.04), tumors located in upper or middle lobe (P = 0.02), tumor size >3 cm (P = 0.01), and SUV_max of primary tumor >4.0 g/ml (P = 0.04) as significant risk factors for MLN metastasis. The pattern of occult MLN metastasis was typical for NSCLC cases. The size of metastatic foci were small, with 68% of foci smaller than 4.0 mm.

Conclusions

The present study demonstrated that adenocarcinoma, tumors located in the upper or middle lobe, tumor size >3 cm, and SUV_max of primary tumor >4.0 g/ml are risk factors for occult MLN metastasis in patients with NSCLC who were diagnosed as clinical N0-1 by preoperative integrated FDG-PET/CT and CT. Patients with tumors located in the right upper or middle lobe are considered candidates for cervical mediastinoscopy because the involved metastatic mediastinal lymph nodes are easily accessible by these modalities.     

PET scan evaluation of thymic mass after autologous peripheral blood stem-cell transplantation in an adult with non-Hodgkin's lymphoma

We report the case of a 31-year-old man with anaplastic large-cell lymphoma successfully treated with chemotherapy who showed mediastinal widening 5 months after autologous stem-cell transplantation. CT scan and PET evaluations were consistent with the diagnosis of benign thymic hyperplasia. Because of the rapid and aggressive course of this type of lymphoma, and the progressive widening of the mass at CT scan, we performed a mediastinal biopsy that confirmed these findings, showing normal thymic tissue. This is the first case of benign thymic hyperplasia defined with FDG-PET and confirmed by histologic evaluation.     

Assessment and significance of mediastinal bulk in Hodgkin's disease: comparison between computed tomography and chest radiography.

PURPOSE: In Hodgkin's disease (HD), mediastinal bulk is currently defined from chest radiograph (CXR) measurements as a ratio of the maximum transverse mass diameter to the internal thoracic diameter at T5/6 level > or = 0.33. We evaluated how computed tomographic (CT) measurements of bulk correspond to those obtained from the CXR and correlated nodal mass long axis diameter with freedom from progression. METHODS: Ninety-five adult patients who had a CXR thoracic ratio of greater than 0.3 and a CT scan within 28 days of the CXR were included in the study, provided that both investigations were performed before the start of treatment. Measurements of the widest mediastinal diameter and internal thoracic diameter were made on both CXR and CT scan. The thoracic ratio (TR) was calculated for each modality and compared using paired t tests. The longest diameter of the largest individual nodal mass (LIM(CT)) was also measured from the CT and correlated with freedom from progression using Cox regression. RESULTS: There was excellent correlation between CT and CXR for measurement of TR, with TR(CT) greater than TR(CXR) (mean difference of 2%). A TR(CT) of 0. 35 was found to be equivalent to a TR(CXR) of 0.33. No single measurement of nodal size correlated with the current definition of bulk. However LIM(CT) greater than 10 cm did correlate with increased risk of progressive HD (P =.03), even after adjustment for other prognostic variables (chemotherapy regimen and Hasenclever Prognostic Index). CONCLUSION: Excellent correlation was observed between assessment of TR by CXR and CT scan. The longest diameter of the LIM(CT) greater than 10 cm was found to be associated with an increased risk of disease progression.     

A case of primary lung cancer lesion demonstrated by F-18 FDG positron emission tomography/computed tomography (PET/CT) one year after the detection of metastatic brain tumor

Cancer of unknown primary origin (CUP) is an aggressive disease with a poor prognosis. Metastatic brain tumors occur in approximately 15% of all cancer patients. F-18 2'-deoxy-2fluoro-D-glucose (FDG) positron emission tomography (PET) combined with computed tomography (PET/CT) contributes to the evaluation of cancer staging, although the benefits of PET/CT for detection of CUP origins has yet to be determined. In this study, we present a 37-year-old man with a brain tumor detected by magnetic resonance imaging. Surgical biopsy indicated a metastatic undifferentiated carcinoma, while clinical examination and a CT scan did not detect any abnormalities, with the exception of brain metastases. PET/CT did not reveal abnormal FDG uptake. PET/CT revealed abnormal intense FDG uptake in a small nodular lesion in the right lung 1 year following the detection of brain metastasis, and no other abnormal FDG uptake was observed elsewhere in the body. Right upper lobectomy and dissection of mediastinal lymph nodes were performed. The pathological diagnosis was poorly differentiated adenocarcinoma, which was similar to the brain metastatic lesion, and there was no lymph node metastasis. This case revealed an extremely rare lung cancer with primary lesions demonstrated by PET/CT 1 year after the detection of brain metastasis. This case reveals that F-18 FDG PET/CT imaging of CUP origin is capable of positively impacting on the identification of small primary tumor foci.     

非小细胞肺癌纵隔淋巴结转移危险因素分析及术前纵隔镜检查的应用策略

目的 探讨纵隔镜技术评估非小细胞肺癌(NSCLC)术前纵隔淋巴结状态(是否存在转移)的临床应用策略.方法 2000年10月至2007年6月,对临床连续收治的经病理确诊的临床分期为Ⅰ～Ⅲ期的NSCLC患者152例,分别采用CT和纵隔镜技术评估纵隔淋巴结状态.根据纵隔淋巴结最终病理结果,计算CT下纵隔肺门淋巴结阴性NSCLC的纵隔镜检查阳性率和实际纵隔淋巴结转移发生率.以患者性别、年龄、肿瘤部位、病理类型、肿瘤T分期、肿瘤类型(中央型或外周型)、CT下纵隔淋巴结大小和血清癌胚抗原(CEA)水平等作为预测因子,进行纵隔淋巴结转移危险因素的单因素和多因素分析.结果 69例CT下纵隔肺门淋巴结阴性NSCLC,纵隔镜检查阳性8例,阳性率为11.6%;实际纵隔淋巴结转移14例,发生率为20.1%.62例临床Ⅰ期(cT1～2NOMO)NSCLC,纵隔镜检查阳性7例,阳性率为11.3%;实际纵隔淋巴结转移12例,发生率为19.4%.对全部152例NSCLC患者纵隔淋巴结转移危险因素的分析结果显示,病理类型和CT下纵隔淋巴结大小是纵隔淋巴结转移的独立危险因素.对69例CT下纵隔肺门淋巴结阴性NSCLC患者纵隔淋巴结转移危险因素的分析结果显示,病理类型是纵隔淋巴结转移的独立危险因素.结论 对于CT下纵隔淋巴结短径≥1 cm的NSCLC患者,术前必须进行纵隔镜检查;对于腺癌患者,即使是CT下纵隔肺门淋巴结短径<1 cm,术前也应该进行纵隔镜检查.     

17例恶性肿瘤18氟脱氧葡萄糖PET显像假阴性的分析

目的 探讨恶性肿瘤^18氟脱氧葡萄糖（^18F—FDG）PET假阴性患者的FDG摄取特点、影响因素,分析PET／CT检查中CT对其的辅助诊断价值。方法 收集行PET／CT检查者中,^18F-FDGPET为阴性的17例恶性肿瘤患者,对其PET图像进行视觉观察和半定量分析,并与CT及病理检查结果进行对比分析。结果 6例肝癌患者病理证实为高分化型肝细胞肝癌,其中1例有两处病灶,一处病灶FDG摄取、平扫CT密度较周围正常肝组织低下,另一处病灶FDG摄取、平扫CT均为阴性;后行增强CT显示在动脉期两处病灶均明显强化。1例胃印戒细胞癌伴右侧附件转移患者,1例腹壁、大网膜转移性腺癌患者,3例肾透明细胞癌患者和1例前列腺癌患者（高分化型）的^18F—FDGPET诊断受消化道正常生理性FDG摄取或泌尿系统FDG滞留的影响。3例转移癌病变直径≤1cm,其中2例的原发病灶FDG摄取明显增高,1例原发病灶^18F—FDGPET及CT诊断为阴性。68．8％原发肿瘤、66．7％转移肿瘤在平扫CT上显示异常密度,并精确定位;而31．2％原发肿瘤、33．3％转移肿瘤病变^18 F—FDGPET及CT诊断均为阴性。结论恶性肿瘤^18F—FDGPET假阴性与病理学类型、分化程度及病灶大小有关;结合CT或重视PET显像方法可减少恶性肿瘤^18F—FDGPET假阴性。     

PET/CT in the evaluation of response to treatment of liver metastases from colorectal cancer with bevacizumab and irinotecan

The present approach at our institution for the treatment of patients with colorectal (CRC) cancer and with liver metastases planned for metastasectomy is the neoadjuvant administration of Bevacizumab with Irinotecan based therapy. Metabolic imaging of tumor viability with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), and simultaneous anatomic localization provided by low-dose non-enhanced computed tomography (CT), can be obtained in a combined modality FDG-PET/CT scan. The purpose of this study was to evaluate the possible contribution of FDG-PET/CT as a surrogate marker to evaluate treatment response of liver metastases in vivo. This is a retrospective evaluation of 18F-FDG PET and CT findings in the first seven consecutive patients. FDG-PET/CT scans were performed before the start of the neoadjuvant and after four cycles of therapy, just prior to surgery. Results were compared to concurrent contrast-enhanced CT, when required, and pathology. Response to treatment was determined according to RECIST size criteria obtained from data from thin (3-5mm) slice CT, and changes in uptake of 18F-FDG uptake on PET. A total of 20 liver lesions were evaluated in seven patients. Overall, 6/7 patients had favorable response to treatment, and only one had progression of disease. One patient was found to be inoperable at surgery. Biopsy was obtained in 1/4 lesions in this patient, while pathology was unable for the remaining three lesions. As such, pathologic validation of findings was available for 17/20 lesions. Complete response (CR) was evident on FDG-PET in 10/17 (58%) lesions, whereas only 4/17(23%) were deemed CR by CT. Similarly, only 1/17 (6%) lesion appeared stable by FDG-PET criteria, whereas three (18%) were termed stable disease (SD) according to size on CT. FDG-PET findings correlated better than CT with pathology, and were more indicative of pathology. Overall PET/CT correctly predicted necrosis at pathology in 70% vs. 35% by CT. Our results suggest that 18F-FDG PET may be instrumental for predicting the pathologic response to Bevacizumab based therapy.