Impact of whole-body 18F-FDG PET on staging and managing patients for radiation therapy.

Whole-body PET with (18)F-FDG has proven to be a very effective imaging modality for staging of malignant tumors. This study was performed to evaluate the impact of (18)F-FDG PET on staging and managing patients for radiation therapy. METHODS: The treatment records of 202 consecutive patients (98 male, 104 female; mean age, 56.9 y; age range, 8-91 y) with different malignant tumors were reviewed. Radiation therapy was intended for all patients. The diagnoses were head and neck tumors (n = 55), gynecologic tumors (n = 28), breast cancer (n = 28), lung cancer (n = 26), malignant lymphomas (n = 24), tumors of the gastrointestinal tract (n = 18), and others (n = 23). Whole-body PET was performed before radiation therapy. The alteration of PET on each patient's staging and management decisions for radiation therapy were determined. RESULTS: For 55 of 202 patients (27%), PET results changed the patients' management in radiation therapy. In 18 cases (9%), PET resulted in a cancellation of radiation therapy because of the detection of previously unknown distant metastases (8 patients), additional lymph node metastases (9 patients), residual tumor (6 patients), or the exclusion of active disease (2 patients). In 6 patients, >1 incremental reason was found for cancellation. In 21 PET examinations (10%), PET results changed the intention of radiation treatment (curative or palliative). The radiation dose was changed in 25 cases (12%). A change of radiation volume was necessary in 12 patients (6%). CONCLUSION: The results of this study show that (18)F-FDG PET has a major impact on the management of patients for radiation therapy, influencing both the stage and the management in 27% of patients.     

The role of 18F-FDG PET in staging and early prediction of response to therapy of recurrent gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are gaining the interest of researchers because of impressive metabolic response to the targeted molecular therapeutic drug imatinib mesylate. Initial reports suggest an impressive role for (18)F-FDG PET in follow-up of therapy for these tumors. However, the role of (18)F-FDG PET versus that of CT has not been established. Therefore, we compared the roles of (18)F-FDG PET and CT in staging and evaluation of early response to imatinib mesylate therapy in recurrent or metastatic GIST. METHODS: The study included 54 patients who underwent (18)F-FDG PET and CT scans within 3 wk before initiation of imatinib mesylate therapy. Forty-nine of these patients underwent repeat scans 2 mo after therapy. The numbers of sites or organs containing lesions on (18)F-FDG PET and CT scans were compared. Corresponding lesions on (18)F-FDG PET and CT scans or those confirmed to be malignant in appearance by other imaging modalities or on follow-up were considered true positives. Lesions seen on (18)F-FDG PET or CT scans but not seen or confirmed to be of benign appearance with other imaging modalities or on follow-up were considered false positives. Measurements of the maximum standard uptake value (SUV) on (18)F-FDG PET scans and tumor size on CT scans were used for quantitative evaluation of early tumor response to therapy. RESULTS: A total of 122 and 114 sites and/or organs were involved on pretherapy (18)F-FDG PET and CT scans, respectively. The sensitivity and positive predictive values (PPVs) for CT were 93% and 100%; whereas these values for (18)F-FDG PET were 86% and 98%. However, the differences between these values for CT and (18)F-FDG PET were not statistically significant (P = 0.27 for sensitivity and 0.25 for PPV). This suggests comparable performance of (18)F-FDG PET and CT in staging GISTs. Repeat scans at 2 mo after therapy showed agreement between (18)F-FDG PET and CT scans in 71.4% of patients (57.1% having a good response to therapy and 14.3% lacking a response). Discrepant results between (18)F-FDG PET and CT were recorded for 28.6% of the patients. (18)F-FDG PET predicted response to therapy earlier than did CT in 22.5% of patients during a longer follow-up interval (4-16 mo), whereas CT predicted lack of response to therapy earlier than (18)F-FDG PET in 4.1%. One patient did not undergo long-term follow-up. These findings suggest that (18)F-FDG PET is superior to CT in predicting early response to therapy in recurrent or metastatic GIST patients. CONCLUSION: The performances of (18)F-FDG PET and CT are comparable in staging GISTs before initiation of imatinib mesylate therapy. However, (18)F-FDG PET is superior to CT in predicting early response to therapy. Thus, (18)F-FDG PET is a better guide for imatinib mesylate therapy.     

Clinical performance of PET/CT in evaluation of cancer: additional value for diagnostic imaging and patient management.

This study assessed the clinical performance of a combined PET/CT system using (18)F-FDG in oncologic patients. METHODS: (18)F-FDG PET/CT was used to evaluate 204 patients with 586 suspicious lesions. All patients had available follow-up data, enabling assessment of the clinical significance of hybrid PET/CT findings. Differences in interpretation between PET, CT, and fused PET/CT data were prospectively documented for detection, localization, and characterization of each evaluated site. The additional value of PET/CT for data interpretation over that of separate PET and CT was classified into several criteria, including change in lesion characterization to either definitely benign or definitely malignant, precise anatomic localization of malignant (18)F-FDG uptake, and retrospective lesion detection on PET and CT. The clinical impact of information provided by PET/CT on patient management was assessed on the basis of follow-up data concerning further diagnostic or therapeutic approach. Analysis of data was performed for the whole study population, for different types of cancer, and for different anatomic sites. RESULTS: PET/CT provided additional information over the separate interpretation of PET and CT in 99 patients (49%) with 178 sites (30%). PET/CT improved characterization of equivocal lesions as definitely benign in 10% of sites and as definitely malignant in 5% of sites. It precisely defined the anatomic location of malignant (18)F-FDG uptake in 6%, and it led to retrospective lesion detection on PET or CT in 8%. The results of PET/CT had an impact on the management of 28 patients (14%). Hybrid PET/CT data obviated the need for further evaluation in 5 patients, guided further diagnostic procedures in 7 patients, and assisted in planning therapy for 16 patients. CONCLUSION: Hybrid PET/CT improves the diagnostic interpretation of (18)F-FDG PET and CT in cancer patients and has an impact on both diagnostic and therapeutic aspects of patient management.     

18F-FDG PET/CT in patients with suspected recurrent or metastatic well-differentiated thyroid cancer.

PET using 18F-FDG has been shown to effectively detect various types of cancer by their increased glucose metabolism. The aim of this study was to evaluate the use of coregistered PET and CT (PET/CT) in patients with suspected thyroid cancer recurrence. METHODS: After total thyroidectomy followed by radioiodine ablation, 61 consecutive patients with elevated thyroglobulin levels or a clinical suspicion of recurrent disease underwent 18F-FDG PET/CT. Of these, 59 patients had negative findings on radioiodine (131I) whole-body scintigraphy (WBS). Fifty-three of the 61 patients had both negative 131I WBS findings and elevated thyroglobulin levels. PET/CT images were acquired 60 min after intravenous injection of 400-610 MBq of 18F-FDG using a combined PET/CT scanner. Any increased 18F-FDG uptake was compared with the coregistered CT image to differentiate physiologic from pathologic tracer uptake. 18F-FDG PET/CT findings were correlated with the findings of histology, postradioiodine WBS, ultrasound, or clinical follow-up serving as a reference. The diagnostic accuracy of 18F-FDG PET/CT was evaluated for the entire patient group and for those patients with serum thyroglobulin levels of less than 5, 5-10, and more than 10 ng/mL. RESULTS: Thirty patients had positive findings on 18F-FDG PET/CT; 26 were true-positive and 4 were false-positive. In 2 patients, increased 18F-FDG uptake identified a second primary malignancy. 18F-FDG PET/CT results were true-negative in 19 patients and false-negative in 12 patients. The overall sensitivity, specificity, and accuracy of 18F-FDG PET/CT were 68.4%, 82.4%, and 73.8%, respectively. The sensitivities of 18F-FDG PET/CT at serum thyroglobulin levels of less than 5, 5-10, and more than 10 ng/mL were 60%, 63%, and 72%, respectively. Clinical management changed for 27 (44%) of 61 patients, including surgery, radiation therapy, or chemotherapy. CONCLUSION: Coregistered 18F-FDG PET/CT can provide precise anatomic localization of recurrent or metastatic thyroid carcinoma, leading to improved diagnostic accuracy, and can guide therapeutic management. In addition, the findings of this study suggest that further assessment of 131I WBS-negative, thyroglobulin-positive patients by 18F-FDG PET/CT may aid in the clinical management of selected cases regardless of the thyroglobulin level.     

Comparison of diagnostic ability between 99mTc-MDP bone scan and 18F-FDG PET/CT for bone metastasis in patients with small cell lung cancer

Objective

The aim of this study was to compare the diagnostic ability of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) with that of ^99mTc-methylene diphosphonate (^99mTc-MDP) bone scan for bone metastasis in staging patients with small cell lung cancer (SCLC).

Methods

Ninety-five patients with SCLC who underwent both ¹⁸F-FDG PET/CT and ^99mTc-MDP bone scan for initial staging work-up were retrospectively enrolled. All ¹⁸F-FDG PET/CT and bone scan images were visually assessed. Bone metastasis was confirmed by histopathological results and all available clinical information.

Results

Of 95 patients with SCLC, metastatic bone lesions were found in 30 patients, and 84 metastatic lesions were evaluated on a lesion-basis analysis. The sensitivity of ¹⁸F-FDG PET/CT was 100?% on a per-patient basis and 87?% on a per-lesion basis, and there was no false-positive lesion on PET/CT images. In contrast, the sensitivity of the bone scan was 37?% on a per-patient basis and 29?% on a per-lesion basis. The bone scan showed 11 false-positive lesions. The bone scan detected two metastatic lesions that were not detected by PET/CT, which were outside the region scanned by PET/CT. On follow-up bone scan, 21 lesions that were not detected by the initial bone scan but were detected by PET/CT were newly detected.

Conclusions

In patients with SCLC, ¹⁸F-FDG PET/CT showed higher detection rate of bone metastasis than ^99mTc-MDP bone scan. Thus, ¹⁸F-FDG PET/CT can replace bone scan in staging patients with SCLC.     

The impact of 18F-FDG PET/CT on assessment of nasopharyngeal carcinoma at diagnosis

The aim of this study was to determine whether the use of whole-body (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography (PET)/CT alters staging and management of nasopharyngeal carcinoma (NPC) when compared with current staging practice. 52 patients with Stage III-IV NPC without distant metastases on chest X-ray/CT, abdominal ultrasound or bone scan were recruited for the study. Whole-body (18)F-FDG PET/CT and MRI of the head and neck were performed. The scans were compared for extent of the primary tumour (PT), cervical nodal metastases (CNM) and distant metastases (DM). Any discordance in results was assessed with respect to staging and impact on management. MRI and (18)F-FDG PET/CT scans were discordant in 28 (54%) patients. There was discordance in the extent of PT at 28 sites; in all sites, MRI showed more extensive tumour involving the nasopharynx (n = 8), skull base (n = 14), brain (n = 4) and orbit (n = 2). There was also variation among the extent of CNM in four nodes of the retropharyngeal region, with the nodes being positive on MRI. (18)F-FDG PET /CT did not identify any additional distant metastases but did identify a second primary tumour in the colon. The additional use of (18)F-FDG PET/CT did not "up-stage" the overall stage or change management in any patient. In conclusion, there is discordance between MRI and (18)F-FDG PET/CT, and the additional use of (18)F-FDG PET/CT for the current assessment of NPC at diagnosis does not appear to be justified in this cohort of patients.     

Influence of <Superscript>18</Superscript>F-FDG PET/CT on therapy management in patients with stage III/IV malignant melanoma

Purpose

To evaluate the influence of ¹⁸F-FDG PET/CT in comparison to CT alone on treatment decisions in patients with advanced melanoma and to analyse the 5-year survival data in comparison to literature data.

Methods

Therapy management in 64 consecutive patients (primary staging n?=?52; surveillance n?=?12) with stage III/IV melanoma who underwent ¹⁸F-FDG PET/CT between 2004 and 2005 in our department was retrospectively analysed. Treatment decisions were made by two dermatooncologists for each patient twice, first based on the CT results and then based on the PET/CT results. Therapy changes based on the PET/CT results were classified as “major” (e.g. change from metastasectomy to systemic therapy) or “minor” (e.g. change from first to second line chemotherapy). The 5-year survival data of different patient cohorts were calculated.

Results

In the 52 patients in the primary staging group, the results of ¹⁸F-FDG PET/CT led to therapy change in 59 % and a major therapy change in 52 %. ¹⁸F-FDG PET/CT led to the avoidance of futile operations in 13 patients with suspicious lesions on CT that were deemed nontumorous on PET/CT. In the 12 patients in the surveillance group, the results of ¹⁸F-FDG PET/CT led to therapy change in 33 % and a major change in 17 %. The 5-year survival rates were 30 % in the entire cohort, 34 % in the primary staging group, and 17 % in the surveillance group. A significant overall survival benefit was observed in patients in whom ¹⁸F-FDG PET/CT excluded metastases or in whom metastases could be completely removed compared with patients who were not eligible for surgery (41 % vs. 10 %).

Conclusion

Primary staging of patients with stage III/IV melanoma should be performed with ¹⁸F-FDG PET/CT, leading to higher diagnostic accuracy and enabling individualized therapeutic management, especially optimal patient selection for metastasectomy. This strategy may extend long-term survival even in patients with advanced disease.

     

Routine (18)F-FDG PET preoperative staging of colorectal cancer: comparison with conventional staging and its impact on treatment decision making.

The preoperative staging of colorectal cancer (CRC) with (18)F-FDG PET is not as yet generally considered to be evidence based. We have found only 1 study that evaluated (18)F-FDG PET in a nonselected population with proven CRC. Several other studies have concentrated on more advanced disease. The aim of this study was to assess the potential clinical benefit of (18)F-FDG PET in the routine staging of CRC. METHODS: Thirty-eight consecutive patients who had had CRC histologically proven by colonoscopy underwent prospective preoperative staging by plain chest radiography, sonography, CT, and (18)F-FDG PET. Sensitivity, specificity, and accuracy were retrospectively assessed by comparison with the histologic results after surgery (36 patients) or clinical follow-up (2 inoperable cases-both patients died within 1 y of the PET examination). The impact of (18)F-FDG PET on therapeutic decision making was evaluated by comparing medical records before and after (18)F-FDG PET. RESULTS: (18)F-FDG PET correctly detected 95% of primary tumors, whereas CT and sonography correctly detected only 49% and 14%, respectively. Lymph nodes were involved in 7 patients. The sensitivity, specificity, and accuracy of (18)F-FDG PET were 29%, 88%, and 75%, respectively. CT and sonography did not reveal any lymph node involvement. Liver metastases were present in 9 patients. (18)F-FDG PET, CT, and sonography had a sensitivity of 78%, 67%, and 25%, respectively; a specificity of 96%, 100%, and 100%, respectively; and an accuracy of 91%, 91%, and 81%, respectively. (18)F-FDG PET revealed further lesions in 11 patients. Levels of carcinoembryonic antigen and carbohydrate antigen 19-9 tumor markers were elevated in, respectively, only 33% and 8% of cases of proven CRC. (18)F-FDG PET changed the treatment modality for 8% and the range of surgery for 13% of patients. In total, (18)F-FDG PET changed the method of treatment for 16% of patients. CONCLUSION: Plain chest radiography and sonography did not bring any clinical benefits. No correlation was found between the level of tumor markers and the stage of disease. CT is necessary for confirmation of PET findings at extraabdominal sites (PET-guided CT) and for their morphologic specification at abdominal and pelvic sites before an operation. (18)F-FDG PET is the best method for the staging of CRC in all localities, despite the high rate of false-negative PET findings in patients with lymph node involvement. PET should be performed as a first examination after verification of CRC. We propose a PET/CT hybrid system as optimal in the staging of CRC.     

^18F-FDG PET/CT对可疑复发性宫颈癌的临床价值

目的 探讨^18F-FDG PET/CT在可疑复发性宫颈癌临床诊疗中的价值.方法 回顾性分析51例宫颈癌根治后随访期间临床可疑复发的患者,记录患者的治疗资料、可疑复发表现、18F-FDG PET/CT显像结果、同期常规影像检查结果、病理及临床随访结果、PET/CT结果对临床诊疗的影响.结果 PET/CT诊断宫颈癌复发43例,最终经病理检查及临床随访证实复发性宫颈癌40例,盆腔脓肿2例,放射性肠炎1例;PET/CT未见恶性征象8例,病理检查及临床随访均未见异常.PET/CT诊断复发性宫颈癌灵敏度为100.00%（40/40）,特异性为72.73%（8/11）,准确性为94.12%（48/51）.PET/CT指导制订临床诊疗及随访计划34例,改变治疗计划7例.与其他影像检查相比,PET/CT可发现更多的病灶.结论^18F-FDG PET/CT能有效诊断复发性宫颈癌,指导临床诊疗.     

18F-FDG PET/CT对可疑复发性宫颈癌的临床价值

目的 探讨18F-FDG PET/CT在可疑复发性宫颈癌临床诊疗中的价值.方法 回顾性分析51例宫颈癌根治后随访期间临床可疑复发的患者,记录患者的治疗资料、可疑复发表现、18F-FDG PET/CT显像结果、同期常规影像检查结果、病理及临床随访结果、PET/CT结果对临床诊疗的影响.结果 PET/CT诊断宫颈癌复发43例,最终经病理检查及临床随访证实复发性宫颈癌40例,盆腔脓肿2例,放射性肠炎1例;PET/CT未见恶性征象8例,病理检查及临床随访均未见异常.PET/CT诊断复发性宫颈癌灵敏度为100.00%(40/40),特异性为72.73%(8/11),准确性为94.12%(48/51).PET/CT指导制订临床诊疗及随访计划34例,改变治疗计划7例.与其他影像检查相比,PET/CT可发现更多的病灶.结论 18F-FDG PET/CT能有效诊断复发性宫颈癌,指导临床诊疗.     

Clinical utility of 18F-FDG PET for patients with salivary gland malignancies.

The clinical utility of 18F-FDG PET in evaluating salivary gland malignancies has not been well defined. We therefore evaluated the utility of 18F-FDG PET in management for patients with salivary gland cancers. METHODS: Thirty-four patients with newly diagnosed salivary gland cancers underwent CT and 18F-FDG PET before surgical resection with radiotherapy. The diagnostic accuracies of CT and 18F-FDG PET for detecting primary tumors and neck metastases were compared with a histopathologic reference. We determined the relationship between the maximum standardized uptake value (SUV) of the tumor and clinicopathologic parameters such as sex, age, local tumor invasion, T and N categories, TNM stage, and histologic grade, as well as their associations with disease-free survival (DFS). RESULTS: 18F-FDG PET was more sensitive than CT for the detection of primary tumors (91.2% vs. 79.4%; P < 0.05), cervical metastases (80.5% vs. 56.1%; P < 0.05), and distant metastases in 2 patients at initial staging. High-grade malignancies had higher mean maximum SUVs than did low- and intermediate-grade malignancies (4.6 vs. 2.8; P = 0.011). T and N categories were independent determinants of DFS (P < 0.05), but the maximum SUV (4.0) was not. During a mean follow-up of 25.1 mo, 18F-FDG PET correctly diagnosed local-regional recurrences in 6 patients and new distant metastases in 9 patients. CONCLUSION: Our findings indicate that, in patients with salivary gland malignancies, 18F-FDG PET is clinically useful in initial staging, histologic grading, and monitoring after treatment but not in predicting patient survival.     

<Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography in uterine carcinosarcoma

Purpose Uterine carcinosarcomas clinically confined to the uterus usually harbor occult metastases. We conducted a pilot study to evaluate the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in uterine carcinosarcoma. Methods Patients with histologically confirmed uterine carcinosarcoma were enrolled. Abdominal and pelvic magnetic resonance imaging (MRI)/whole-body computed tomography (CT) scan, and whole-body ¹⁸F-FDG PET or PET/CT were undertaken for primary staging, evaluating response, and restaging/post-therapy surveillance. The clinical impact of ¹⁸F-FDG PET was determined on a scan basis. Results A total of 19 patients were recruited and 31 ¹⁸F-FDG PET scans (including 8 scans performed on a PET/CT scanner) were performed. Positive impacts of scans were found in 36.8% (7/19) for primary staging, 66.7% (2/3) for monitoring response, and 11.1% (1/9) for restaging/post-therapy surveillance. PET excluded falsely inoperable disease defined by MRI in two patients. Aggressive treatment applying to three patients with PET-defined resectable stage IVB disease seemed futile. Two patients died of disease shortly after salvage therapy restaged by PET. With PET monitoring, one stage IVB patient treated by targeted therapy only was alive with good performance. Using PET did not lead to improvement of overall survival of this series compared with the historical control (n = 35) (P = 0.779). Conclusions The preliminary results suggest that ¹⁸F-FDG PET is beneficial in excluding falsely inoperable disease for curative therapy and in making a decision on palliation for better quality of life instead of aggressive treatment under the guidance of PET. PET seems to have limited value in post-therapy surveillance or restaging after failure.     

Breast cancer staging in a single session: whole-body PET/CT mammography

Our objective was to compare the diagnostic accuracy of an all-in-one protocol of whole-body 18F-FDG PET/CT and integrated 18F-FDG PET/CT mammography with the diagnostic accuracy of a multimodality algorithm for initial breast cancer staging. METHODS: Forty women (mean age, 58.3 y; range, 30.8-78.4 y; SD, 12 y) with suspected breast cancer were included. For the primary tumor, we compared 18F-FDG PET/CT mammography versus MRI mammography; for axillary lymph node status, 18F-FDG PET/CT versus clinical investigation and ultrasound; and for distant metastases, 18F-FDG PET/CT versus a multimodality staging algorithm. Histopathology and clinical follow-up served as the standard of reference. The Fisher exact test evaluated the significance of differences (P < 0.05). Alterations in patient management caused by 18F-FDG PET/CT were documented. RESULTS: No significant differences were found in the detection rate of breast cancer lesions (18F-FDG PET/CT, 95%; MRI, 100%; P = 1). 18F-FDG PET/CT correctly classified lesion focality significantly more often than did MRI (18F-FDG PET/CT, 79%; MRI, 73%; P < 0.001). MRI correctly defined the T stage significantly more often than did 18F-FDG PET/CT (MRI, 77%; 18F-FDG PET/CT, 54%; P = 0.001). 18F-FDG PET/CT detected axillary lymph node metastases in 80% of cases; clinical investigation/ultrasound, in 70%. This difference was not statistically significant (P = 0.067). Distant metastases were detected with 18F-FDG PET/CT in 100% of cases, and the multimodality algorithm identified distant metastases in 70%. This difference was not statistically significant (P = 1). Three patients had extraaxillary lymph node metastases that were detected only by PET/CT (cervical, retroperitoneal, mediastinal/internal mammary group). 18F-FDG PET/CT changed patient management in 12.5% of cases. CONCLUSION: Our data suggest that a whole-body 18F-FDG PET/CT mammography protocol may be used for staging breast cancer in a single session. This initial assessment of the 18F-FDG PET/CT protocol indicates similar accuracy to MRI for the detection of breast cancer lesions. Although MRI seems to be more accurate when assessing the T stage of the tumor, 18F-FDG PET/CT seems able to more accurately define lesion focality. Although 18F-FDG PET/CT mammography was able to detect axillary lymph node metastases with a high sensitivity, this method cannot soon be expected to replace the combination of clinical examination, ultrasound, and sentinel lymph node biopsy for axillary assessment.     

Is 18F-3'-fluoro-3'-deoxy-L-thymidine useful for the staging and restaging of non-small cell lung cancer?

The objective of this study was to compare 18F-3'-fluoro-3'-deoxy-L-thymidine (FLT) PET with clinical TNM staging, including that by 18F-FDG PET, in patients with non-small cell lung cancer (NSCLC). METHODS: Patients with NSCLC underwent whole-body 18F-FDG PET and whole-body 18F-FLT PET, using a median of 360 MBq of 18F-FDG (range, 160-500 MBq) and a median of 210 MBq of 18F-FLT (range, 130-420 MBq). 18F-FDG PET was performed 90 min after 18F-FDG injection, and 18F-FLT PET was performed 60 min after 18F-FLT injection. Two viewers independently categorized the localization and intensity of tracer uptake for all lesions. All 18F-FDG PET and 18F-FLT PET lesions were compared. Staging with 18F-FLT PET was compared with clinical TNM staging based on the findings of history, physical examination, bronchoscopy, CT, and 18F-FDG PET. From 8 patients, standardized uptake values (SUVs) were calculated. Maximal SUV and mean SUV were calculated. RESULTS: Sixteen patients with stage IB-IV NSCLC and 1 patient with strong suspicion of NSCLC were investigated. Sensitivity on a lesion-by-lesion basis was 80% for the 8 patients who received treatment before 18F-FLT PET and 27% for the 9 patients who did not receive pretreatment, using 18F-FDG PET as the reference standard. Compared with clinical TNM staging, staging by 18F-FLT PET was correct for 8 of 17 patients: 5 of 9 patients in the group with previous therapy and 3 of 8 patients in the group without previous therapy. The maximal SUV of 18F-FLT PET, at a median of 2.7 and range of 0.8-4.5, was significantly lower than that of 18F-FDG PET, which had a median of 8.0 and range of 3.7-18.8 (n = 8; P = 0.012). The mean SUV of 18F-FLT PET, at a median of 2.7 and range of 1.4-3.3, was significantly lower than that of 18F-FDG PET, which had a median of 6.2 and range of 2.8-13.9 (n = 6; P = 0.027). CONCLUSION: 18F-FLT PET is not useful for staging and restaging NSCLC.     

Diagnostic accuracy of 18F-FDG PET/CT in characterizing ovarian lesions and staging ovarian cancer: correlation with transvaginal ultrasonography, computed tomography, and histology

AIMS: To (a) assess the accuracy of 18F-FDG PET/CT in distinguishing malignant from benign pelvic lesions, compared to transvaginal ultrasonography (TVUS) and (b) to establish the role of whole-body 18F-FDG PET/CT, compared to contrast enhanced computed tomography (CT), in staging patients with ovarian cancer. PATIENTS: Fifty consecutive patients with a pelvic lesion, already scheduled for surgery on the basis of physical examination, TVUS, and serum Ca125 levels, were enrolled in the study. Patients' age ranged between 23 and 89 years (mean 64). All patients underwent TVUS including a colour Doppler study followed by a thorax and abdominal CT scan, and whole-body 18F-FDG PET/CT within 2 weeks prior to surgery. Histological findings obtained at surgery were taken as the 'gold standard' to compare 18F-FDG PET/CT and TVUS, and 18F-FDG PET/CT vs. CT. When tissue analysis showed ovarian cancer, the accuracy of 18F-FDG PET/CT and CT were compared for the purpose of obtaining a precise staging. RESULTS: At surgery, the ovarian lesions were malignant in 32/50 patients (64%) and benign in the remaining 18/50 patients (36%). The sensitivity, specificity, NPV, PPV and accuracy of 18F-FDG PET/CT were 87%, 100%, 81%, 100% and 92%, respectively, compared with 90%, 61%, 78%, 80% and 80%, respectively, for TVUS. In staging ovarian cancer, 18F-FDG PET/CT results were concordant with final pathological staging in 22/32 (69%) patients while CT results were concordant in 17/32 (53%) patients. CT incorrectly down-staged four out of six stage IV patients by missing distant metastasis in the liver, pleura, mediastinum, and in left supraclavicular lymph nodes, which were correctly detected by 18F-FDG PET/CT. CONCLUSION: PET/CT with 18F-FDG provides additional value to TVUS for the differential diagnosis of benign from malignant pelvic lesions, and to CT for the staging of ovarian cancer patients.     

(18)F-FDG PET provides high-impact and powerful prognostic stratification in staging newly diagnosed non-small cell lung cancer.

Survival of lung cancer patients remains poor despite increasingly aggressive treatment. Conventional staging has well-described limitations. (18)F-FDG PET has been shown to stage lung cancer more accurately than does CT scanning, but the impact on patient treatment and outcome is poorly defined. This study evaluated this impact in routine clinical practice within a tertiary oncology facility. METHODS: For 153 consecutive patients with newly diagnosed non-small cell lung cancer, the treatment plan based on conventional staging methods was compared with the treatment plan based on incorporation of PET findings. Survival was analyzed using the Cox proportional hazards regression model. RESULTS: For broad groupings of stage, 10% of cases were downstaged and 33% upstaged by PET. When assessable, the PET stage was confirmed in 89% of patients. PET had a high impact on 54 patients (35%), including 34 whose therapy was changed from curative to palliative, 6 whose therapy was changed from palliative to curative, and 14 whose treatment modality was changed but not the treatment intent. For 39 patients (25%), a previously selected therapy was altered because of the PET findings. The Cox model indicated that the pre-PET stage was significantly associated with survival (P = 0.013) but that the post-PET stage provided much stronger prognostic stratification (P < 0.0001) and remained significant after adjustment for treatment delivered. CONCLUSION: Staging that incorporated PET provided a more accurate prognostic stratification than did staging based on conventional investigations. Further, the additional information provided by PET significantly and appropriately changed management in the majority of patients.     

The clinical impact of (18)F-FDG PET in patients with suspected or confirmed recurrence of colorectal cancer: a prospective study.

This prospective study aimed to confirm, in a clinical setting, the benefits suggested by earlier retrospective studies of (18)F-FDG PET scanning for the evaluation of patients with suspected recurrence of colorectal cancer. METHODS: The referring oncologist was asked to prospectively assign a treatment plan for 102 consecutive patients being evaluated by (18)F-FDG PET for suspected or confirmed recurrence of colorectal cancer and without evidence of unresectable disease on conventional staging investigations, including CT. This treatment plan was then compared with that based on incremental information supplied by PET. Management changes were validated by follow-up. RESULTS: For 6 patients, the oncologist would not commit to a management plan without access to PET information, and for all these patients, PET correctly guided management. Of the remaining 96 patients, the management plan for 54 (56%) was altered as a direct result of unexpected PET findings. Thus, PET directly influenced management in 60 (59%) of 102 patients. The discrepant PET results could be validated in 57 patients and were correct for both the presence and the extent of malignant disease in 52 (91%) of these patients but were false-positive in 1 patient because of a pelvic abscess and underestimated the extent of metastatic disease in 4 (7%). Relapse was confirmed in 49 (98%) of 50 evaluable patients with positive PET findings. Significantly, planned surgery was abandoned in 26 (60%) of 43 patients because of incremental PET findings. Of the 42 patients for whom management was not changed by PET findings, false-negative PET findings were documented for 5 (4 with metastases < 1 cm), and the PET findings for 1 were presumed to be false-positive because of sarcoidosis. CONCLUSION: This prospective study confirms the high impact, suggested by previous retrospective analyses, of (18)F-FDG PET on management of patients with suspected recurrent colorectal cancer. The major benefit of PET is avoidance of inappropriate local therapies by documentation of widespread disease.     

The impact of PET on the management of lung cancer: the referring physician's perspective.

(18)F-FDG PET is a molecular whole-body imaging modality that is increasingly being used for diagnosing, staging, and restaging cancer. The objective of this study was to determine referring physicians' perspectives on the impact of (18)F-FDG PET on staging and management of lung cancer. METHODS: A questionnaire was sent to the 292 referring physicians of 744 consecutive patients with known or suspected lung cancer who were evaluated with PET. Questionnaires on 274 patients were returned (response rate, 37%). Management changes were categorized as intermodality (e.g., surgery to medical, surgery to radiation, and medical to no treatment) or intramodality (e.g., altered medical, surgical, or radiotherapy approach). RESULTS: The primary reasons for PET referral were staging of lung cancer in 61% of patients, diagnosis in 20%, and monitoring of therapy or the course of disease in 6%. Physicians reported that PET caused them to change their decision on clinical stage in 44% of all patients: The disease was upstaged in 29% and downstaged in 15%. PET resulted in intermodality management changes in 39% of patients, whereas 15% had an intramodality change. CONCLUSION: This survey-based study of referring physicians suggests that PET has a major impact on staging and management of lung cancer.     

Clinical role of (18)F-FDG PET for initial staging of patients with extrahepatic bile duct cancer

In extrahepatic bile duct cancer, preoperative evaluation is important because only surgical excision of all detectable tumours is associated with improvement in 5-year survival. However, morphological imaging techniques, including computed tomography (CT), are still insufficient for accurate staging. The purpose of this study was to assess the additional value, in relation to CT, of 2-[(18)F]fluoro-2-deoxy- D-glucose positron emission tomography ((18)F-FDG PET) for the evaluation of extrahepatic bile duct cancer. Thirty patients with extrahepatic bile duct cancer underwent both (18)F-FDG PET and CT for initial staging. The results of the two modalities for evaluation of primary tumours and regional lymph nodes were compared with the final diagnoses based on pathological or clinical findings. The primary tumours were interpreted as malignant on the basis of CT in 24 (80%) of the patients, while (18)F-FDG PET revealed increased (18)F-FDG uptake in 18 (60%) of them. On the other hand, (18)F-FDG PET showed focal accumulation of (18)F-FDG in the bile duct in three of the six patients with equivocal findings on CT. The sensitivity, specificity and accuracy of CT for regional lymph node metastases were 54%, 59% and 57%, while those of (18)F-FDG PET were 38%, 100% and 73%, respectively. The specificity of (18)F-FDG PET for regional lymph node metastases was significantly higher than that of CT ( P<0.01). Of 14 patients with N1 or N2 disease diagnosed by CT, only seven (50%) had a final diagnosis of regional lymph node metastasis. In these 14 patients, (18)F-FDG PET accurately evaluated the N component of the disease in 12 patients (86%). In conclusion, in the initial staging of patients with extrahepatic bile duct cancer, (18)F-FDG PET offers additional value in relation to CT in evaluating both the primary tumour and regional lymph nodes.     

PET-CT bei Lymphompatienten

PURPOSE: First results of PET/CT in Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) are reported. PATIENTS AND METHODS: From March 2001 to August 2004 822 PET/CT were performed at our clinic in lymphoma patients for primary staging, restaging after therapy, and diagnosis of recurrence. For coregistration non contrast-enhanced low-dose CT were used. RESULTS: Due to the exact anatomic localization of (18)F-FDG accumulating lesions equivocal or false positive PET findings are avoided. In comparison to contrast enhanced CT, PET/CT has a higher sensitivity and specificity in patients with HD and aggressive NHL. Integration of PET/CT in treatment planning of radiation therapy optimizes the field volume. CONCLUSION: Even in the initial phase of clinical evaluation, PET/CT has proven useful in staging and restaging of lymphoma. The exact anatomic localization of the PET findings is essential for a precise report, for treatment planning of radiation therapy, and for planning surgical biopsy.